• Title/Summary/Keyword: new joint

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Experimental study on through-beam connection system for concrete filled steel tube column-RC beam

  • Tian, Chunyu;Xiao, Congzhen;Chen, Tao;Fu, Xueyi
    • Steel and Composite Structures
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    • v.16 no.2
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    • pp.187-201
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    • 2014
  • A new through-beam connection system for a concrete filled steel tube column to RC beam is proposed. In this connection, there are openings on the steel tube while the reinforced concrete beams are continuous in the joint zone. The moment and shear force at the beam ends can be transferred to column by continuous rebar and concrete. The weakening of the axial load and shear bearing capacity due to the opening of the steel tube can be compensated by strengthening steel tube at joint zone. Using this connection, construction of the joint can be made more convenient since welding and hole drilling in situ can be avoided. Axial compression and reversed cyclic loading tests on specimens were carried out to evaluate performance of the new beam-column connection. Load-deflection performance, typical failure modes, stress and strain distributions, and the energy dissipation capacity were obtained. The experimental results showed that the new connection have good bearing capacity, superior ductility and energy dissipation capacity by effectively strengthen the steel tube at joint zone. According to the test and analysis results, some suggestions were proposed to design method of this new connection.

Histologic Change of Extracorporeal Irradiated Autogenous Joint Transplantation in Rabbit's Knee (가토에서 체외 방사선 조사후 재이식한 자가관절의 조직학적 변화)

  • Kim, Jae-Do;Cho, Myung-Rae;Yoo, Kyung-Sik;Kim, Young-Chang
    • The Journal of the Korean bone and joint tumor society
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    • v.5 no.1
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    • pp.9-16
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    • 1999
  • A new method of limb sparing by resection, extracorporeal irradiation and reimplantation has several theoretical advantages. This method preserves the mobility of a joint and avoids the problem of loosening or breakage of tumor prosthesis. This study involved using extracorporeal irradiated autogenous joint transplantation for reconstruction after en bloc resection, and observed the periods of functional union and histological changes in irradiated tissue of the knee joint. This study also aimed to clarify whether the degeneration of articular cartilage is induced in rabbits by a single 50Gy dose of irradiation at the knee joint. Twenty New Zealand rabbits about three kilograms were randomized into two groups of 10 rabbits each. In group 1, as control, we resected the knee joint followed by reimplantation without irradiation. Group 2 received extracorporeal irradiation on the resected knee joint followed by reimplantation. Following are the results of these observations. The osteotomy site showed external callus formation in the roentgenographic finding eight weeks after reimplantation. There was marked degenerative changes in the collagen fiber of the irradiated anterior cruciate ligament and meniscus during the fourth week, but new blood-vessel formation was observed in the vicinity. There was degenerative changes in the collagen fiber of articular cartilage treated extracorporeal irradiation at four and eight weeks in the scanning electron micrographic findings. These findings was in contrast to those of subchondral bone which showed decreased cellularity and empty lacuna at four and eight weeks. Autoradiography demonstrated active [$^3H$]uridine incorporation by irradiated chondrocyte at eight weeks after reimplantation. These results indicate that when destruction of the articular cartilage and soft tissue of the knee joint is not severe, extracorporeal irradiation and reimplantation can be used with several advantage in maintaining movement of the joint while avoiding problems of tumor prosthesis and rejection, and therefore extracorporeal irradiated autogenous joint transplantation can be used as a limb-sparing procedure for temporary biological spacer in the childhood bone tumor around the knee.

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Effects of joint aspect ratio on required transverse reinforcement of exterior joints subjected to cyclic loading

  • Chun, Sung Chul
    • Earthquakes and Structures
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    • v.7 no.5
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    • pp.705-718
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    • 2014
  • This paper presents an analytical model for determining the transverse reinforcement required for reinforced concrete exterior beam-column joints subjected to reversed cyclic loading. Although the joint aspect ratio can affect joint shear strength, current design codes do not consider its effects in calculating joint shear strength and the necessary amount of transverse reinforcement. This study re-evaluated previous exterior beam-column joint tests collected from 11 references and showed that the joint shear strength decreases as the joint aspect ratio increases. An analytical model was developed, to quantify the transverse reinforcement required to secure safe load flows in exterior beam-column joints. Comparisons with a database of exterior beam-column joint tests from published literature validated the model. The required sectional ratios of horizontal transverse reinforcement calculated by the proposed model were compared with those specified in ACI 352R-02. More transverse reinforcement is required as the joint aspect ratio increases, or as the ratio of vertical reinforcement decreases; however, ACI 352R-02 specifies a constant transverse reinforcement, regardless of the joint aspect ratio. This reevaluation of test data and the results of the analytical model demonstrate a need for new criteria that take the effects of joint aspect ratio into account in exterior joint design.

미세직경 악관절경을 이용한 악관절 closed lock 환자의 치료

  • Lee, Sang-Hwa;Choie, Mok-Kyun;Chung, Hoon
    • The Journal of the Korean dental association
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    • v.41 no.12 s.415
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    • pp.818-824
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    • 2003
  • Visually guided irrigation and lysis(VGIL) using temporomandibular joint(TMJ) arthroscope is useful for decreasing pain and increasing the functional mobility of TMJ. Also it demonstrated similar effectiveness comparing with arthrocentesis. Arthroscopy permits intracapsular inspection that is imperative not only for identification of morphological characteristics of joint space, but also for adequate irrigation and lysis of specific joint space. Conventional 2.3mm diameter arthroscope with 2.7mm catheter was too wide. So it was traumatic and uncomfortable to manipulate on temporomandibular joint space, especially on TMJ internal derangement patient with reduced space. We report our clinical experience on 6 TMJ closed lock patients who were treated with new 1.2mm fiberscope at Chung Hoon Dental Clinic between March 2003 and August 2003. Also we present clinical advantage & disadvantage of new system with literature review.

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Development of Optimum Design Technique for Bus Window Pillar Member (버스 윈도우 필라 부재의 형상 최적 설계기술 개발)

  • 김명한;김대성;임석현;서명원;배동호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.6
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    • pp.156-164
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    • 1999
  • The body structure of a bus is generally assembled by using various spot welded box sectional members. The shape of window pillar joint is ordinarily built up by T-type member. It has been shown that T-type member has problems like high stress concentrations, low fatigue strength and low structural rigidity. In this study, to solve these problems a new approach to optimize the design of the bus window pillar joint was tried by FEM analysis and experiments. To describe the shape of the gusset connecting the vertical and horizontal members of the T-type window pillar joint B-spline curve was adopted and this curve was optimized . It was found that the new model developed could effectively improve fatigue durability an structural rigidity.

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Robot Calibration with Joint Stiffness Parameters for the Enhanced Positioning Accuracy (위치 정밀도 향상을 위한 관절강성 파라미터 포함 로봇 캘리브레이션)

  • Kang, Hee-Jun;Shin, Sung-Won;Ro, Young-Shick;Suh, Young-Soo;Lim, Hyun-Kyu;Kim, Dong-Hyeok
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.4
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    • pp.406-410
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    • 2008
  • This paper presents a new robot calibration algorithm with joint stiffness parameters for the enhanced positioning accuracy of industrial robot manipulators. This work is towards on-going development of an industrial robot calibration software which is able to identify both the kinematic and non-kinematic robot parameters. In this paper, the conventional kinematic calibration and its important considerations are briefly described first. Then, a new robot calibration algorithm which simultaneously identifies both the kinematic and joint stiffness parameters is presented and explained through a computer simulation with a 2 DOF manipulator. Finally, the developed algorithm is implemented to Hyundai HX165 robot and its resulting improvement of the positioning accuracy is addressed.

Characterization of Predicted Residual Sum of Squares for Detecting Joint Influence in Regression (회귀(回歸)에서 결합영향력(結合影響力)를 위(爲)한 예측잔차(豫測殘差)제곱합(合)의 특성(特性)에 대(對)한 연구(硏究))

  • Oh, Kwang-Sik
    • Journal of the Korean Data and Information Science Society
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    • v.3 no.1
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    • pp.1-16
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    • 1992
  • In regression diagnostics, a number of joint influence measures based on various statistical tools have been discussed. We consider an alternate representation in terms of the predicted residual and g-leverage determined by the remaining points. By this approach, we choose the predicted residual sum of squares for the keypoints as joint influence measure and propose a new expression of it so that we can extend the single case form to the multiple case one. Furthermore we suggest a seach method for joint influence after investigating some properties of the new expression.

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Performance Enhancement of the Joint CDMA/PRMA Protocol Using Pseudo Bayesian Approach (의사 베이지안 접근법을 이용한 Joint CDMA/PRMA의 성능 향상에 관한 연구)

  • Kim, Kyungsoo;Kwangho Kook;Lee, Kangwon;Jiwhan Ahn;Park, Jeongrak
    • Journal of the Korean Operations Research and Management Science Society
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    • v.24 no.1
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    • pp.49-58
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    • 1999
  • A new channel access function is proposed to enhance the performance of the Joint CDMA/PRMA. It is obtained in consideration of the number of terminals in reservation mode and the number of terminals in contention mode whose probability distribution is estimated by applying pseudo Bayesian approach. Simulation results show that the performance of the Joint CDMA/PRMA can be improved by applying new channel access function under voice-only traffic and mixed voice/random-data traffic.

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Novel computational approaches characterizing knee physiotherapy

  • Kim, Wangdo;Veloso, Antonio P.;Araujo, Duarte;Kohles, Sean S.
    • Journal of Computational Design and Engineering
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    • v.1 no.1
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    • pp.55-66
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    • 2014
  • A knee joint's longevity depends on the proper integration of structural components in an axial alignment. If just one of the components is abnormally off-axis, the biomechanical system fails, resulting in arthritis. The complexity of various failures in the knee joint has led orthopedic surgeons to select total knee replacement as a primary treatment. In many cases, this means sacrificing much of an other-wise normal joint. Here, we review novel computational approaches to describe knee physiotherapy by introducing a new dimension of foot loading to the knee axis alignment producing an improved functional status of the patient. New physiotherapeutic applications are then possible by aligning foot loading with the functional axis of the knee joint during the treatment of patients with osteoarthritis.

Structural Performance Evaluation of Bolt Connection for Half-sphere Joint between PHC Pile and Steel Column (강재기둥-PHC 파일 간 반구형 접합부(HAT Joint)의 볼트 연결에 대한 구조성능평가)

  • Oh, Jintak;Kim, Sang-Bong;Kim, Young-Sik;Ju, Young K.
    • Journal of Korean Association for Spatial Structures
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    • v.15 no.4
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    • pp.65-72
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    • 2015
  • To overcome the weakness of spread foundation in large space structure, the research of precast pile for replace spread foundation have been conducted. The new type of joint between PHC pile and steel column is named HAT Joint(Hollow hAlf-sphere cast-sTeel Joint). It connected PHC Pile by bolt that verification of bolt connection should be accomplished. In this paper, pull-out test and flexural performance for HAT Joint to verifying the bolt connection is explained. As a result, the pull-out and flexural capacities of bolt were checked to use in real structure. Furthermore, the equation of pull-out strength was proposed.