• Title/Summary/Keyword: WRAP

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Strength model for square concrete columns confined by external CFRP sheets

  • Benzaid, Riad;Mesbah, Habib Abdelhak
    • Structural Engineering and Mechanics
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    • v.46 no.1
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    • pp.111-135
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    • 2013
  • An experimental study has been carried out on square plain concrete (PC) and reinforced concrete (RC) columns strengthened with carbon fiber-reinforced polymer (CFRP) sheets. A total of 78 specimens were loaded to failure in axial compression and investigated in both axial and transverse directions. Slenderness of the columns, number of wrap layers and concrete strength were the test parameters. Compressive stress, axial and hoop strains were recorded to evaluate the stress-strain relationship, ultimate strength and ductility of the specimens. Results clearly demonstrate that composite wrapping can enhance the structural performance of square columns in terms of both maximum strength and ductility. On the basis of the effective lateral confining pressure of composite jacket and the effective FRP strain coefficient, new peak stress equations were proposed to predict the axial strength and corresponding strain of FRP-confined square concrete columns. This model incorporates the effect of the effective circumferential FRP failure strain and the effect of the effective lateral confining pressure. The results show that the predictions of the model agree well with the test data.

Error Analysis Caused by Using the Dftin Numerical Evaluation of Rayleigh's Integral (레일리 인테그랄의 수치해석상 오차에 대한 이론적 고찰)

  • Kim, Sun-I.
    • Journal of Biomedical Engineering Research
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    • v.10 no.3
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    • pp.323-330
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    • 1989
  • Large bias errors which occur during a numerical evaluation of the Rayleigh's integral is not due to the replicated source problem but due to the coincidence of singularities of the Green's function and the sampling points in Fourier domain. We found that there is no replicated source problem in evaluating the Rayleigh's integral numerically by the reason of the periodic assumption of the input sequence in Dn or by the periodic sampling of the Green's function in the Fourier domain. The wrap around error is not due to an overlap of the individual adjacent sources but berallse of the undersampling of the Green's function in the frequency domain. The replicated and overlApped one is inverse Fourier transformed Green's function rather than the source function.

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Stamping Analysis and Die Design of Laser Welded Automotive Body (레이저 용접 차체의 성형해석과 금형설계)

  • Kim, Heon-Young;Shin, Yong-Seung;Kim, Koan-Hoi;Cho, Won-Seok
    • Transactions of Materials Processing
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    • v.7 no.4
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    • pp.382-392
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    • 1998
  • Computer simulations and test trials were carried out to obtain the optimal stamping conditions of the die design of the laser welded automotive body. The stamping process including gravity deflection bead calibration binder wrap, forming and spring back was simulated and compared with the results obtained from test trials. The production variables were determined from a preliminary operation and they were investigated in the simulation and the test trials. The formability was tested under the various conditions, such as the initial position of blank, blank holding force, corner radius and the shape of drawbead. Sound products without fracture, wrinkling and excessive weldline movement were produced by applying results obtained this investigation.

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Compressive Strength Enhancement of Concrete Cylinders Confined with FRP Wrapping (FRP로 횡보강된 콘크리트 공시체의 압축강도 향상에 관한 연구)

  • 김영섭;정영수;박창규;송희원
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.11a
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    • pp.351-354
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    • 2003
  • Triaxial behavior of concrete cylinders wrapped with FRP material has been investigated for the increase of concrete strength by lateral confinement. Using the model by Richart et al., a modified empirical equation was proposed to estimate the strength of concrete cylinders with FRP confinement based on the linear relationship between the concrete strength and lateral confining pressure. From the experimental stress-strain result of the cylinder specimens having similar confining pressure, less ductility was observed for higher strength concrete. But the compressive strength of the specimen was linearly increased by lateral confinement. The confinement effectiveness coefficient for the strength enhancement of the cylinders by FRP wrap was obtained as 2.27 from the regression analysis.

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Autogenous tooth bone graft block for sinus augmentation with simultaneous implant installation: a technical note

  • Lee, Kwang-Ho;Kim, Young-Kyun;Cho, Woo-Jin;Um, In-Woong;Murata, Masaru;Mitsugi, Masaharu
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.41 no.5
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    • pp.284-289
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    • 2015
  • In cases of severe alveolar bone atrophy in the posterior maxillary area, which has only a thin sinus floor, the autogenous tooth bone graft block (ABTB) was used to wrap the implant to enhance its primary stability and osseointegration in the sinus. These cases with four years of clinical follow-up demonstrate the applicability of the ABTB in maxillary sinus membrane elevation to improve the outcomes of implant placement.

Experimental Study on the Reduction of Noise Dispersion for HEV Relay (HEV 계전기의 소음분산 저감에 관한 실험적 연구)

  • Kim, Wonjin
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.2
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    • pp.324-330
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    • 2013
  • The dispersion of acoustic noise during the turn-on and turn-off switching of HEV(hybrid electric vehicle) relay was experimentally analyzed to identify the reason for the dispersion of noise level. An effective method was proposed to reduce the dispersion of noise level. First, a method to wrap the side of moving core with a tape was adopted to reduce the transverse vibration. It enabled the moving core to make a consistent motion and reduce the dispersion of noise level from switching operation of relay. Second, the dispersion of noise level from vibration transmission of parts such as the outer frame and yoke caulking part of relay were tested to find out main sources. From this result, it was identified that the yoke caulking part made inconsistent transient vibration and noise dispersion.

EFFECT OF GINGER RHIZOME EXTRACT ON TENDERNESS AND SHELF LIFE OF PRECOOKED LEAN BEEF

  • Kim, K.J.;Lee, Y.B.
    • Asian-Australasian Journal of Animal Sciences
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    • v.8 no.4
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    • pp.343-346
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    • 1995
  • The inclusion of crude ginger rhizome (zingiber officinale) extract at 0.5 to 1.0% (v/w) in the marination of marginally acceptable lean beef improved meat tenderness by 20-30% in the absence of 2% salt and by 35-45% in the presence of 2% salt. Ginger extract also retarded the development of rancidity and increased shelf-life of precooked lean beef two-fold in saran-wrap (no vacuum) storage at $4^{\circ}C$. Ginger rhizome improves the palatability and acceptability of lean beef from carcasses of marginal quality. It is particularly beneficial for the preparation of pre-cooked ready-to-eat beef products that are not vacuum-packaged.

Consumption and Preference of Korean Perilla Leaves(Penilla frutescens var. japonica Hara) by Daejeon Area Consumers (연령에 따른 대전 지역 소비자들의 깻잎 소비 형태 및 기호도 조사)

  • Chung, Hea-Jung;Cheon, Hee-Sook
    • Journal of the East Asian Society of Dietary Life
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    • v.20 no.2
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    • pp.193-200
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    • 2010
  • The study examined the preference and style of consumption of perilla leaves(Perilla frutescens var. japonica Hara), a popular food item in Korea, by consumers in the Daejeon area. Of the respondents 35.2% purchased perilla leaves in a large super-market limited to two to three bundles. Comsumer preferences were to consume the leaves raw or pickled with salt or soy sauce, or use as a fish soup ingredient. The majority of consumers aged 20~29-years-of age preferred to wrap sashimi with perilla leaves. As a side dish, regardless of age, consumers preferred to pan-fried perilla leaves with mincedmeat and perilla leaves.

On the Stability of the Axially Compliant Fixed Scroll Member in Scroll Compressors

  • Hyun Jin Kim
    • International Journal of Air-Conditioning and Refrigeration
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    • v.10 no.1
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    • pp.40-49
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    • 2002
  • Floating fixed scroll adopted for tip sealing enhancement in a scroll compressor is always under the influence of tipping moment produced by internal gas forces. Unless the tipping moment is property compensated by some restoring moment, the fired scroll would suffer tipping movement, degrading the compressor performance. The condition on which the tipping movement of the fixed scroll can be suppressed has been investigated analytically. For no tipping movement, the floating fixed scroll should be suspended on the main frame at proper level. The upper limit of the stable suspension is the axial location of the o-rings adopted for a back pressure chamber sealing on the rear side of the fixed scroll, and the lower limit is the mid-height of the scroll wrap.

Development of CDMA Hierarchical Cellular Simulator using Object-Oriented-Program (객체지향프로그램을 이용한 CDMA 계층 셀 시뮬레이터 개발)

  • Kim, Ho-Joon
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.29 no.3
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    • pp.111-118
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    • 2006
  • This paper presents design and development of a simulator evaluates the performance of a hierarchical cellular system. The proposed hierarchical cellular simulator, consisting of macro, micro, and pico cells, applies the wrap-around technique to reduce simulation time. The simulator is implemented as object oriented class models by using the C++ language in a PC environment. The resulting application can evaluate the interference, SIR(Signal to Interference Ratio), and capacity of a hierarchical cellular system in various configurations. Moreover, it can be used in other applications such as power control, call admission control, hand over scheme.