• Title/Summary/Keyword: knee elements

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On the characteristics and seismic study of Hat Knee Bracing system, in steel structures

  • JafarRamaji, Issa;Mofid, Massood
    • Steel and Composite Structures
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    • v.13 no.1
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    • pp.1-13
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    • 2012
  • In this study, a new structural bracing system named 'Hat Knee Bracing' (HKB) is presented. In this structural system, a special form of diagonal braces, which is connected to the knee elements instead of beam-column joints, is investigated. The diagonal elements provide lateral stiffness during moderate earthquakes. However the knee elements, which is a fuse-like component, is designed to have one plastic joint in the knee elements for dissipation of the energy caused by strong earthquake. First, a suitable shape for brace and knee elements is proposed through elastic studying of the system and several practical parameters are established. Afterward, by developing applicable and highly accurate models in Drain-2DX, the inelastic behavior of the system is carefully considered. In addition, with inelastic study of the new bracing system and comparison with the prevalent Knee Bracing Frame system (KBF model) in nonlinear static and dynamic analysis, the seismic behavior of the new bracing system is reasonably evaluated.

Study of an innovative two-stage control system: Chevron knee bracing & shear panel in series connection

  • Vosooq, Amir Koorosh;Zahrai, Seyed Mehdi
    • Structural Engineering and Mechanics
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    • v.47 no.6
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    • pp.881-898
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    • 2013
  • This paper describes analytical investigation into a new dual function system including a couple of shear links which are connected in series using chevron bracing capable to correlate its performance with magnitude of earthquakes. In this proposed system, called Chevron Knee-Vertical Link Beam braced system (CK-VLB), the inherent hysteretic damping of vertical link beam placed above chevron bracing is exclusively utilized to dissipate the energy of moderate earthquakes through web plastic shear distortion while the rest of the structural elements are in elastic range. Under strong earthquakes, plastic deformation of VLB will be halted via restraining it by Stopper Device (SD) and further imposed displacement subsequently causes yielding of the knee elements located at the bottom of chevron bracing to significantly increase the energy dissipation capacity level. In this paper first by studying the knee yielding mode, a suitable shape and angle for diagonal-knee bracing is proposed. Then finite elements models are developed. Monotonic and cyclic analyses have been conducted to compare dissipation capacities on three individual models of passive systems (CK-VLB, knee braced system and SPS system) by General-purpose finite element program ABAQUS in which a bilinear kinematic hardening model is incorporated to trace the material nonlinearity. Also quasi-static cyclic loading based on the guidelines presented in ATC-24 has been imposed to different models of CK-VLB with changing of vertical link beam section in order to find prime effectiveness on structural frames. Results show that CK-VLB system exhibits stable behavior and is capable of dissipating a significant amount of energy in two separate levels of lateral forces due to different probable earthquakes.

A Simulation Model of the ACL Function Using MADYMO (마디모를 이용한 전방십자인대 기능 시뮬레이션 모델)

  • Park, Jung-Hong;Son, Kwon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.11 s.254
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    • pp.1408-1416
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    • 2006
  • A mathematical knee model was constructed using MADYMO. The purpose of this study is to present a more realistic model of the human knee to reproduce human knee motion. Knee ligaments were modeled as line elements and the surrounding muscles were considered as passive restraint elements. A calf-free-drop test was performed to validate the suggested model. A calf was dropped from the rest at about 65 degree flexed posture in the prone position. The motion data were recorded using four video cameras and then three dimensional data were acquired by Kwon3D motion analysis software. The results showed that general shapes of angular quantities were similar in both the experiment and computer simulation. Functional stability of the anterior cruciate ligament was explicitly revealed through this model.

Kinematics and Kinetics of the Lower Limbs of a Walking Shoe with a Plate Spring and Cushioning Elements in the Heel during Walking

  • Park, Seung-Bum;Stefanyshyn, Darren;Pro, Stergiou;Fausto, Panizzolo;Kim, Yong-Jae;Lee, Kyung-Deuk
    • Korean Journal of Applied Biomechanics
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    • v.20 no.1
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    • pp.13-23
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    • 2010
  • The purposes of this study was to investigate the biomechanical influence of the walking shoe with a plate spring in the heel and interchangeable heel cushioning elements. Eighteen subjects walked in three conditions: 1) the walking shoes Type A-1 with a soft heel insert, 2) the Type A-2 shoe with a stiff heel insert, 3) a general walking shoe(Type B). Ground reaction forces, leg movements, leg muscle activity and ankle, knee and hip joint loading were measured and calculated during overground walking. During walking, the ankle is a few degrees more dorsiflexed during landing and the knee is slightly more flexed during takeoff with the Type A shoes. As a result of the changes in the walking movement, the ground reaction forces are applied more quickly and the peak magnitudes are higher. Muscle activity of the quadricep, hamstring and calf muscles decrease during the first 25% of the stance phase when walking in the Type A shoes. The resultant joint moments at the ankle, knee and hip joints decrease from 30-40% with the largest reductions occurring during landing.

Effects of Peer Mentoring Program on the Health Conservation in Elderly Women with Osteoarthritis (동료멘토링 프로그램이 골관절염 여성노인의 건강보존에 미치는 효과)

  • Nam, Jiran;Sung, Kiwol
    • Research in Community and Public Health Nursing
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    • v.28 no.3
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    • pp.227-239
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    • 2017
  • Purpose: The purpose of this study was to investigate the effects of peer mentoring program on physical activity, knee joint function, self-care agency and social support, which are health conservation elements in elderly women with osteoarthritis. Methods: This study used a quasi-experimental research design. It is a pretest-and-post 1, post 2 test design of a non-equivalent control group. The subjects were elderly women aged over 65 who were diagnosed with osteoarthritis. A total of 60 patients (experimental group 30, control group 30) who registered with the Senior Welfare Center in City G and in Region D participated in this study. The data were collected from June 29th to September 4th, 2015. The collected data were analyzed with $x^2$ test, Fisher's exact test, independent t-test and repeated measurement ANOVA. Results: The experimental group showed a greater increase in physical activity, knee joint function, self-care agency and social support than the control group. Conclusion: The results indicated that the peer mentoring program is effective in increasing physical activity, knee joint function, self-care agency and social support of elderly women with osteoarthritis.

A study the concerns of patient with the knee ligament injury (무릎 인대 손상환자의 퇴원 전.후 관심사)

  • Hyun, Hye-Young;Choi, Kyung-Sook
    • Journal of muscle and joint health
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    • v.3 no.2
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    • pp.216-228
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    • 1996
  • This study has purpose to perform leaving the hospital nursing plan during hospital treatment of patient with the knee ligament Injury on the basis of the concerns between the time of leaving the hospital after 2 weeks in hospital and the concerns through practical life after leaving the hospital systematically. This study is also tried to make exercise plan to prevent atrophy of Quardriceps muscle of the thigh caused by the limitation of activities. The subjects of study are 12 people who were in the hospital in affiliation to a university in Seoul, were operated on the knee ligament, and were discharged from the hospital within 2 weeks. Data collection time was for about 4 months from December, 94 to March, 95. Research method was performed 2 times by unorganized open questions. The collection of first data is through direct interview about the concerns before leaving the hospital, and secondary data is through direct interview about the concerns by practical life and experiences after leaving the hospital. The data was categorized by classifying several common elements among similar contents according to data by the situational analysis of Giorgi. The result of this study is as follows : 1) The concerns before leaving the hospital are like that the concerns of recovery possibility, the limitation of activities, the grim realities of life, the lack of confidence about self-nursing, the eyes of the surroundings, the burden to the others, and so on. 2) The concerns after leaving the hospital are like that the demands of the inconvenience by the limitation of self-nursing, the support about self-nursing by the difficulties of performing treatment order, the support of physical activities limitation by physical tiredness and the limitation of social activities, the support of information by the necessities of education in using crutches before leaving the hospital and continuing informational needs, psychological and mental support of normal physical recovery by the worries of physical recovery and physical change, and social support by thankfulness for his family and relatives. I suggest to make more systematic leaving the hospital nursing plan and exercise education plan for nursing plan after leaving the hospital of the patients with the knee ligament injury on the basis of this content.

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Electro-fatigue Characteristic of Shape Memory Alloy Applied to the Electrosurgical Knee Wand of Variation of Wand Head Angle in Electrosurgical Knee Surgeries (헤드각이 변화하는 Electrosurgical Knee Wand에 적용된 형상기억합금 스프링의 전기적 피로특성)

  • An, Jae-Uk;Kim, Cheol-Woong;Lee, Ho-Sang;Wang, Joon-Ho;Oh, Dong-Joon
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1547-1552
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    • 2008
  • The tip of these catheter with straight needles is not able to reach in the vicinity of the disc bulging, which are the cause of the low back pain and because the far indirect radio-frequency treatment results in the decompression, the nucleoplasty has the limit. Many incurable diseases has not been solved due to the unexistence of the advanced technique for the MIS human body catheter device. To increase the possibility of nucleoplasty, the needle tip should be located at the closest area of the lesion. For this reason, the best way to increase the success rate of the operation is that the needle tip should access 3-dimensionally to the operating field as soon as possible. To achieve this aim, our studies are restricted as follows: 1) the SMA catheter design to control the 3-dimensional direction, 2) the security of the immediate response by the positive control of the SMA element thermal distribution using Peltier thermoelectric elements, 3) the aquisition of the control data by monitoring the relationship between the temperature of SMA element and the displacement, and 4) the design of the controller to guarantee the accurate location.

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Development of Birdcage RF coil for 3T Animal MR Imaging

  • 추명자;최보영;강세권;최치봉;이형구;서태석
    • Progress in Medical Physics
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    • v.13 no.2
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    • pp.85-89
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    • 2002
  • We authors developed a new small-size birdcage RF coil for animal MR images. And we compared signal-to-noise ratio (SNR) of the new small coil with a conventional knee coil. The dimension of the low-pass type birdcage coil with 12 elements at 37 MRI system are 13 cm outer diameter, 12 cm inner diameter and 20 cm length. For each element, the width of copper tape is 0.05 mm, thickness is 8 mm and length is 20 cm. The small birdcage coil with 12 elements exhibited 7 resonance modes. The isolation of the quadrature channel could be achieved more than 20 ㏈. The coil quality factor (Q value) was 98.6. The SNR of the animal coil was 243.2 on the average and was about twice as high as the conventional knee coil. The present study successfully demonstrated that the small birdcage coil could provide high quality animal MR images with the improved SNR. Therefore, it is expected that the small birdcage coil could be used in the clinical diagnosis and research studies for veterinary medicine in the near future.

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The Parametric Fashion Design Using Grasshopper -Focused on Skirt Silhouette

  • Jung Min, Kim;Jung Soo, Lee
    • Journal of Fashion Business
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    • v.26 no.6
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    • pp.32-46
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    • 2022
  • The purpose of this study is to explore a three-dimensional (3D) simulation of skirt shape concepts by manipulating circumferences and lengths via parametric design in the fashion design concept stage. This study also intends to propose a modeling method that can judge and transform the shape through immediate parameter adjustment. We looked at cases that utilized parametric design in other fields of fashion design, reviewed and analyzed the variables used in each study, and constructed parameters suitable to implement skirt fashion design. The traditional design elements required for skirt design, namely waist and hip circumferences, were set as variables in this study. The parametric design was developed to generate ideas of two skirt silhouettes (tight and flared) and three lengths (mini, knee-length, and maxi). To apply the skirt design implemented through variables to the actual 3D human shape, the shape data of women in their 20s and 30s were randomly selected from the 5th human data of Size Korea. Skirt design silhouette modeling was performed by adjusting the variable values according to body type. Parametric design has the potential to help develop design ideas in the field of fashion design, considering the method and characteristics of parameters of the variety of variables and rapid modification. Furthermore, if systematic research on variables and options among fashion design elements is conducted, the possibility of converging them into customization or co-design fashion design processes could be confirmed.

Design Development for Toddler's Playwear (유아(幼兒)의 놀이복 디자인 개발 연구)

  • Lee, Youn-Hee;Park, Hye-Won
    • Journal of the Korean Society of Clothing and Textiles
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    • v.33 no.8
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    • pp.1227-1240
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    • 2009
  • This study examines the actual conditions of toddler playwear preference survey for design and function. The study develops proper indoor and outdoor playwear for toddlers based on the analysis. A survey of 200 parents with toddlers between 2 and 6 years old and 120 teachers was conducted to find the conditions and needs for playwear along with the necessary design elements. Second, 6 designs including 3 designs for indoor playwear and 3 designs for outdoor playwear were made. These designs emphasized on soil contamination part, color, pattern, form, material, detail, and fasteners. Art play and cooking play are considered for indoor playwear and ways to decrease contamination on sleeve hem, elbow, chest, and knee were determined through the use of yellow, green, and blue colors. Applying a character and separate top with sleeves were determined. Light with breathable and waterproof fabric was determined. The correct amount of Velcro fasteners or buttons was determined for front fastening in addition a pocket was considered necessary as a detail part. The common design for both boys and girls along with a proper design for diverse play were determined. For outdoor playwear, water play, sand play, movement play, and ecology experience are considered and ways to decease contamination on hip, sleeve hem, and knee should be applied to the design as determined through the use of yellow, green, blue, and red colors. The demands for pattern, form, material, and details were similar to indoor playwear. Zipper and buttons for front fastening were determined. These final 6 playwear designs are presented using CAD WALK DESIGNWARE.