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Three-Dimensional Video Analysis of the Gate Patterns in Normal Children and Hemiplegic Children with Cerebral Palsy (정상아와 편마비 뇌성마비아의 삼차원 보행분석)

  • Lee Jin-Hee;Bae Sung-Soo;Kim Chung-Sun
    • The Journal of Korean Physical Therapy
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    • v.9 no.1
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    • pp.127-145
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    • 1997
  • The purpose of this study wa9 to analyse the gait patterns of two female children with hemiplegic cerebral palsy by using the three-dimensional video motion analysis technique. Case 1 has mild spastic hemiplegia on the right side while Case 3 has moderate spastic hemiplegia on the left side. A group of 10, normal female children of the same age(7-8 years old) were selected as the control group for comparison. Time and distance variables as well as the Center of Mass displacement, and the pelvic and joint motions in three anatomical planes were analysed for this purpose. The following observations were made through the analysis : Case 1 revealed an asymmetrical gait pattern in which the step length of the unaffected side was shorter than that of the affected side, which wan a result of the effort to minimize loading on the affected leg by shortening the swing phase of the unaffected leg. Case 1 scored similar phase ratios, cadence and walking velocity to the normal group. A slight posterior tilt of the pelvis was observed throughout the gait cycle. Less hip and knee flexion than the normal group was observed, and demonstrated hyperextension of the knee in the terminal stance phase. The main problem in case 1 originated from the insufficient dorsiflexion of the affected foot during the swing phase. Therefore, Case 1 has difficulty with foot clearance in the swing phase. Usually, this is compensated for by using exessive hip abduction and medial rotation in conjuction with trunk elevation as well as increased vortical displacement of the center of mass. Case 1 revealed a foot-flat initial contact pattern. Case 2 was characterized by a consistent retraction ef the affected aide of the body througout the gait cycle, As a result, an asymmetrical gait pattern with increased stance phase ratios of the unaffected side was observed. In spite of this the step lengths of both sieds were similar. Case 2 scored lower cadence and walking speed than the normal group with lower gait stability. The main problem in Case 2 originated from an excessive plantaflexion of the affected foot which, in turn, rebutted in high hip and knee flexion. Hyperextension of the knee was observed at mid-stance, and execessive anterior tilt of the pelvis throughout the gait cycle was noticed. A gait pattern with high hip abduction and medial circumduction was maintained for the stability in the stance phase and foot clearance in the swing phase. Case 2 revealed a forefoot-contact initial contact pattern.

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A Study On The Thermal Movement Of The Reactor Coolant System For PWR (가압 경수로의 냉각재 계통 열팽창 거동에 관한 연구)

  • Yoon, Ki-Seok;Park, Taek sang;Kim, Tae-Wan;Jeon, Jang-Hwan
    • Nuclear Engineering and Technology
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    • v.27 no.3
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    • pp.393-402
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    • 1995
  • The structural analysis of the reactor coolant system mainly consist of too fields. The one is the static analysis considering the impact of pressure and temperature built up during normal operation. The other is the dynamic analysis to estimate the impact of postulated events such as the seismic loads or postulated branch line pipe breaks event. Since the most important goal of the RCS structural analysis is to prove the safety of the RCS during normal operation or postulated events, a widely proven theory having enough conservatism is adopted. The load occurring on the RCS during normal operation is considered as the basic design loading condition throughout whole plant life time. The most typical characteristic of the RCS during normal operation is the thermal expansion of the RCS caused by reactor coolant with high temperature and pressure. Therefore, the exact estimation on the thermal movement of the RCS is needed to get more clear understanding on the thermal movement behavior of the RCS. In this study, the general structural analysis concept and modeling method to evaluate the thermal movement of the RCS under the normal plant operation condition are presented. To discuss the validation of the suggested analysis, analysis results are compared with the measured data which ore referred from the standardized 1000 MWe PWR plant under construction.

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A Study on the Structural Behavior and Safety Evaluation based on Field Measurement Value of Launching Truss (런칭 트러스의 안전성 평가 및 실측치에 기초한 구조거동에 관한 연구)

  • Park, Young Hoon;Lee, Seung Yong;Jeon, Jun Chang;Chang, Dong Il
    • Journal of Korean Society of Steel Construction
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    • v.10 no.3 s.36
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    • pp.383-391
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    • 1998
  • Launching truss used for constructing the precast segmental concrete bridge has upper chord, lower chord and diagonal members. And the pin is used for connecting these members. From the field loading test carried out for investigating the actual behavior of launching truss, the great difference is analyzed between measured stress and calculated stress. Based on measured value, the structural analysis are carried out about assumed abnormal behavior of connection part. From the results of analysis, it is analyzed that the abnormal behavior of connection part greatly affect the structural behavior of launching truss. In addition, from the investigation of safety of launching truss, it is evaluated that the launching truss has enough safety with normal behavior of connection part.

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Seismic damage assessment of steel reinforced recycled concrete column-steel beam composite frame joints

  • Dong, Jing;Ma, Hui;Zhang, Nina;Liu, Yunhe;Mao, Zhaowei
    • Earthquakes and Structures
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    • v.14 no.1
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    • pp.73-84
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    • 2018
  • Low cyclic loading tests are conducted on the steel reinforced recycled concrete (SRRC) column-steel (S) beam composite frame joints. This research aims to evaluate the earthquake damage performance of composite frame joints by performing cyclic loading tests on eight specimens. The experimental failure process and failure modes, load-displacement hysteresis curves, characteristic loads and displacements, and ductility of the composite frame joints are presented and analyzed, which shows that the composite frame joints demonstrate good seismic performance. On the basis of this finding, seismic damage performance is examined by using the maximum displacement, energy absorbed in the hysteresis loops and Park-Ang model. However, the result of this analysis is inconsistent with the test failure process. Therefore, this paper proposes a modified Park-Ang seismic damage model that is based on maximum deformation and cumulative energy dissipation, and corrected by combination coefficient ${\alpha}$. Meanwhile, the effects of recycled coarse aggregate (RCA) replacement percentage and axial compression ratio on the seismic damage performance are analyzed comprehensively. Moreover, lateral displacement angle is used as the quantification index of the seismic performance level of joints. Considering the experimental study, the seismic performance level of composite frame joints is divided into five classes of normal use, temporary use, repair after use, life safety and collapse prevention. On this basis, the corresponding relationships among seismic damage degrees, seismic performance level and quantitative index are also established in this paper. The conclusions can provide a reference for the seismic performance design of composite frame joints.

Simulation of the tensile failure behaviour of transversally bedding layers using PFC2D

  • Haeri, Hadi;Sarfarazi, Vahab;Zhu, Zheming;Marji, Mohammad Fatehi
    • Structural Engineering and Mechanics
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    • v.67 no.5
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    • pp.493-504
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    • 2018
  • In this paper, the tensile failure behaviour of transversally bedding layers was numerically simulated by using particle flow code in two dimensions. Firstly, numerical model was calibrated by uniaxial, Brazilian and triaxial experimental results to ensure the conformity of the simulated numerical model's response. Secondly, 21 circular models with diameter of 54 mm were built. Each model contains two transversely bedding layers. The first bedding layer has low mechanical properties, less than mechanical properties of intact material, and second bedding layer has high mechanical properties, more than mechanical properties of intact material. The angle of first bedding layer, with weak mechanical properties, related to loading direction was $0^{\circ}$, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, $75^{\circ}$ and $90^{\circ}$ while the angle of second layer, with high mechanical properties, related to loading direction was $90^{\circ}$, $105^{\circ}$, $120^{\circ}$, $135^{\circ}$, $150^{\circ}$, $160^{\circ}$ and $180^{\circ}$. Is to be note that the angle between bedding layer was $90^{\circ}$ in all bedding configurations. Also, three different pairs of the thickness was chosen in models; i.e., 5 mm/10 mm, 10 mm/10 mm and 20 mm/10 mm. The result shows that In all configurations, shear cracks develop between the weaker bedding layers. Shear cracks angel related to normal load change from $0^{\circ}$ to $90^{\circ}$ with increment of $15^{\circ}$. Numbers of shear cracks are constant by increasing the bedding thickness. It's to be note that in some configuration, tensile cracks develop through the intact area of material model. There is not any failure in direction of bedding plane interface with higher strength.

Verification for the Effect of Growth Hormone Promotion and Kinetic Factor Evaluation on Growth Hormone Activated Shoes (성장호르몬 활성화 신발에 대한 운동역학적(지면반력, 최대압력) 평가 및 성장호르몬 분비 효과 검증)

  • Moon, Young-Jin
    • Korean Journal of Applied Biomechanics
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    • v.18 no.1
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    • pp.235-243
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    • 2008
  • The purpose of this study is to find out the effect of Growth Hormone promotin and kinetic factors on Growth Hormone Activated Shoes. The results of the present study were as follows; First, there was a significient difference between a normal shoes and the Growth Hormone activated shoes in the student's GH secretion with running test, and there was a significant interaction effect between shoes and distance. therefore it can be assumed that there is a significant effect of GH secretion in student at growth period during running with Growth Hormine Activated Shoes. Second, Within 4km walking, Growth Hormone secretion was in creased averagely in student. Third, Growth Hormone Activated Shoes make a large load for light motion as walking. For heavy motion as running, it make a large impulsion but good pressure distribution and small loading rate.

Immediately loaded dental implants with fixed prostheses using a computer-guided surgery in a mental retardation patient: a case report (정신지체장애환자에서 Computer-Guided Surgery를 이용한 임플란트 식립 및 즉시 보철물 장착: 증례보고)

  • Han, Se-Jin
    • Journal of Dental Rehabilitation and Applied Science
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    • v.30 no.3
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    • pp.246-252
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    • 2014
  • $Br{\aa}nemark^{\prime}s$ original protocol required 4 to 6 months for implant osseointegration before placement of the definitive prosthesis. Although this approach gave very predictable results, it had certain drawbacks. The main disadvantages of this approach were prolonged treatment time, two surgical procedures, placement of a removable prosthesis that required modifications during the course of treatment, and a greater number of appointments. Immediate implant loading is a viable treatment method for selected cases. One of the greatest advantages of this method is the virtual surgery, which precedes the actual clinical treatment and eliminates any need for last minute decisions. The actual surgery time is decreased, since all steps are predetermined. These advantages aren't only more useful for normal patients but also for the mental retardation patients whose cooperation is difficult. This article presents a clinical approach made possible due to the guided implant surgery and CAD/CAM technique.

Three-dimensional finite element analysis of the splinted implant prosthesis in a reconstructed mandible

  • Heo, Kyung-Hoi;Lim, Young-Jun;Kim, Myung-Joo;Kwon, Ho-Beom
    • The Journal of Advanced Prosthodontics
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    • v.10 no.2
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    • pp.138-146
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    • 2018
  • PURPOSE. The purpose of this study was to analyze the effects of the splinted implant prosthesis in a reconstructed mandible using three-dimensional finite element analysis. MATERIALS AND METHODS. Three-dimensional finite element models were generated from a patient's computed tomography data. The patient had undergone partial resection of the mandible that covered the area from the left canine to the right condyle. The mandible was reconstructed using a fibula bone graft and dental implants. The left mandibular premolars and molars remained intact. Three types of models were created. The implant-supported prosthesis was splinted and segmented into two or three pieces. Each of these models was further subcategorized into two situations to compare the stress distribution around normal teeth and implants. Oblique loading of 300 N was applied on both sides of the mandible unilaterally. The maximum von Mises stress and displacement of the models were analyzed. RESULTS. The stress distribution of the natural mandible was more uniform than that of the reconstructed fibula. When the loading was applied to the implant prosthesis of reconstructed fibula, stress was concentrated at the cortical bone around the neck of the implants. The three-piece prosthesis model showed less uniform stress distribution compared to the others. Displacement of the components was positively correlated with the distance from areas of muscle attachment. The three-piece prosthesis model showed the greatest displacement. CONCLUSION. The splinted implant prosthesis showed a more favorable stress distribution and less displacement than the separated models in the reconstructed mandible.

The behaviour of strength and fatigue crack propagation of various steels in steel bridges (철강구조물 부재의 강도평가 및 피로균열진전거동)

  • Han, Seung-Ho;Kim, Jung-Kyu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.10
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    • pp.1694-1701
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    • 1997
  • The residual safety assessment of steel structures, an important subject in practice, is given to much attention. Life prediction in the planning course of steel structures under fatigue loading is mainly based on fatigue design criteria resulting from S-N curves. But for any reason cracks have to be assumed due to fabrication failures or fatigue loading in service which can lead total fracture of structures. The life prediction can be carried out by means of fracture mechanics using Paris-Erdogan equation($da/dN=C {\cdot}{\Delta}K^m$). The paper presents results from charpy test to interpret transition behaviour of charpy energy($A_V$) in a wide temperature range and from constant-load-amplitude test to measure fatigue crack growth of various steels widely used in steel bridges since beginning of 20 centuries in Europe. In the normal service temperature range of steel bridges, the steel S355M shows higher maximum charpy energy($A_{Vmax}$) and lower transition temperature($T_{AVmax/2}$) than other steels considered. The C and m of Paris-Erdogan equation on the steels appear to be correlated, and to be affected by the R-ratios due to crack closure, especially at a low fatigue crack growth rate. Scanning electron microscopy analysis was carried out to interpret an influence of the crack closure effects on the correlation of C and m.

A numerical-experimental evaluation of beams composed of a steel frame with welded and conventional stirrups

  • Goncalves, Wagner L.;Gomes, Guilherme F.;Mendez, Yohan D.;Almeida, Fabricio A.;Santos, Valquiria C.;Cunha, Sebastiao S.Jr.
    • Computers and Concrete
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    • v.22 no.1
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    • pp.27-37
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    • 2018
  • Reinforced concrete structures are widely used in civil engineering projects around the world in different designs. Due to the great evolution in computational equipment and numerical methods, structural analysis has become more and more reliable, and in turn more closely approximates reality. Thus among the many numerical methods used to carry out these types of analyses, the finite element method has been highlighted as an optimized tool option, combined with the non-linear and linear analysis techniques of structures. In this paper, the behavior of reinforced concrete beams was analyzed in two different configurations: i) with welding and ii) conventionally lashed stirrups using annealed wire. The structures were subjected to normal and tangential forces up to the limit of their bending resistance capacities to observe the cracking process and growth of the concrete structure. This study was undertaken to evaluate the effectiveness of welded wire fabric as shear reinforcement in concrete prismatic beams under static loading conditions. Experimental analysis was carried out in order compare the maximum load of both configurations, the experimental load-time profile applied in the first configuration was used to reproduce the same loading conditions in the numerical simulations. Thus, comparisons between the numerical and experimental results of the welded frame beam show that the proposed model can estimate the concrete strength and failure behavior accurately.