• Title/Summary/Keyword: fatigue design

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Analysis of Published Research in the Journal of Muscle and Joint Health from 2008 to 2020 (근관절건강학회지 게재 논문 분석: 2008년부터 2020년까지)

  • Park, Mi-Sung;Lee, Kyung-Sook;Shin, Gyeyoung;Woo, Soo-Hee;Lim, Kyung-Choon;Choi, Heejung;Jin, Soo-Ji;Park, Yeon-Hwan
    • Journal of muscle and joint health
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    • v.29 no.1
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    • pp.69-80
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    • 2022
  • Purpose: To identify research trends in the Journal of Muscle and Joint Health. Methods: In total, 315 studies published between 2008 and 2020 in the Journal of Muscle and Joint Health were reviewed using analysis criteria developed by the authors Results: Most participants were adults or older adults, they mostly had arthritis. The types of research design were descriptive research (46.4%), quasi-experimental design (21.9%), randomized controlled trial (1.9%), and qualitative research (4.1%). The occupation of most authors was professor in universities (61.0%). Data were collected mostly in hospitals (41.6%) or communities (24.4%) using a questionnaire (52.4%). Written consent was obtained at 75.6% and 47.9% of studies were approved by the Institutional Review Board (IRB). The instruments measuring physical concepts such as pain, flexibility, sense of balance and fatigue were mostly used. The most common interventions in experimental studies were physical interventions, with the main being exercise. Key words were categorized into four nursing meta-paradigms: human, health, environment and nursing. The most frequently reported key words were included in the health domain. The most frequently used key words were physical intervention, older patient, osteoarthritis, pain and depression. Conclusion: The results suggest that more research studies targeting various age groups related to muscle and joint health are required. Additionally there is a need to increase the number of qualitative studies, randomized experimental studies, and systematic review studies. It is necessary to pay attention to compliance with research ethics publication regulations.

Development of Steel Composite Cable Stayed Bridge Weigh-in-Motion System using Artificial Neural Network (인공신경망을 이용한 강합성 사장교 차량하중분석시스템 개발)

  • Park, Min-Seok;Jo, Byung-Wan;Lee, Jungwhee;Kim, Sungkon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.6A
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    • pp.799-808
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    • 2008
  • The analysis of vehicular loads reflecting the domestic traffic circumstances is necessary for the development of adequate design live load models in the analysis and design of cable-supported bridges or the development of fatigue load models to predict the remaining lifespan of the bridges. This study intends to develop an ANN(artificial neural network)-based Bridge WIM system and Influence line-based Bridge WIM system for obtaining information concerning the loads conditions of vehicles crossing bridge structures by exploiting the signals measured by strain gauges installed at the bottom surface of the bridge superstructure. This study relies on experimental data corresponding to the travelling of hundreds of random vehicles rather than on theoretical data generated through numerical simulations to secure data sets for the training and test of the ANN. In addition, data acquired from 3 types of vehicles weighed statically at measurement station and then crossing the bridge repeatedly are also exploited to examine the accuracy of the trained ANN. The results obtained through the proposed ANN-based analysis method, the influence line analysis method considering the local behavior of the bridge are compared for an example cable-stayed bridge. In view of the results related to the cable-stayed bridge, the cross beam ANN analysis method appears to provide more remarkable load analysis results than the cross beam influence line method.

Comparison of Kinematics and Myoelectrical Activity during Deadlift, with and without Variable Banded Resistance, in Healthy, Trained Athletes

  • Everett B. Lohman;Mansoor Alameri;Fulden Cakir;Chih Chieh Chia;Maxine Shih;Owee Mulay;Kezia Marceline;Simran Jaisinghani;Gurinder Bains;Michael DeLeon;Noha Daher
    • Physical Therapy Rehabilitation Science
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    • v.13 no.1
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    • pp.53-70
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    • 2024
  • Background: The conventional deadlift is a popular exercise for enhancing trunk, core, and lower extremity strength. However, its use in sports medicine is constrained by concerns of lumbar injuries, despite evidence supporting its safety and rehabilitative benefits. To optimize muscle activation using resistive bands in variable resistance therapy, we explored their feasibility in the deadlift. Design: Comparative experimental design Methods: Surface electromyography recorded muscle activity in the trunk and lower extremities during lifting, with normalization to the isometric Floor Lift using Maximal Voluntary Contraction. Kinematics were measured using inclinometer sensors to track hip and trunk sagittal plane angles. To prevent fatigue, each subject only used one of the three pairs of bands employed in the study. Results: Our study involved 45 healthy subjects (mean age: 30.4 ± 6.3 years) with similar baseline characteristics, except for years of lifting and strength-to-years-of-lifting ratio. Various resistance band groups exhibited significantly higher muscle activity than conventional deadlifts during different phases. The minimal resistance band group had notably higher muscle activity in the trunk, core, and lower extremity muscles, particularly in the end phase. The moderate resistance band group showed increased muscle activity in the mid-and end-phases. The maximum resistance band group demonstrated greater muscle activity in specific muscles during the early phase and overall higher activity in all trunk and lower extremity muscles in the mid and end phases of the deadlift (p<0.05). Conclusion: Our findings provide valuable insights into muscle activation with various resistance bands during deadlift exercise in clinical and gym settings. There appears to be a dose-response relationship between increased resistance bandwidth, external load, myoelectric activation, and range.

Wave Analysis and Spectrum Estimation for the Optimal Design of the Wave Energy Converter in the Hupo Coastal Sea (파력발전장치 설계를 위한후포 연안의 파랑 분석 및 스펙트럼 추정)

  • Kweon, Hyuck-Min;Cho, Hongyeon;Jeong, Weon-Mu
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.25 no.3
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    • pp.147-153
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    • 2013
  • There exist various types of the WEC (Wave Energy Converter), and among them, the point absorber is the most popularly investigated type. However, it is difficult to find examples of systematically measured data analysis for the design of the point absorber type of power buoy in the world. The study investigates the wave load acting on the point absorber type resonance power buoy wave energy extraction system proposed by Kweon et al. (2010). This study analyzes the time series spectra with respect to the three-year wave data (2002.05.01~2005.03.29) measured using the pressure type wave gage at the seaside of north breakwater of Hupo harbor located in the east coast of the Korean peninsula. From the analysis results, it could be deduced that monthly wave period and wave height variations were apparent and that monthly wave powers were unevenly distributed annually. The average wave steepness of the usual wave was 0.01, lower than that of the wind wave range of 0.02-0.04. The mode of the average wave period has the value of 5.31 sec, while mode of the wave height of the applicable period has the value of 0.29 m. The occurrence probability of the peak period is a bi-modal type, with a mode value between 4.47 sec and 6.78 sec. The design wave period can be selected from the above four values of 0.01, 5.31, 4.47, 6.78. About 95% of measured wave heights are below 1 m. Through this study, it was found that a resonance power buoy system is necessary in coastal areas with low wave energy and that the optimal design for overcoming the uneven monthly distribution of wave power is a major task in the development of a WEF (Wave Energy Farm). Finding it impossible to express the average spectrum of the usual wave in terms of the standard spectrum equation, this study proposes a new spectrum equation with three parameters, with which basic data for the prediction of the power production using wave power buoy and the fatigue analysis of the system can be given.

Evaluation of the influence of a visual design of an examination guide on patient comprehension and testing accuracy (검사 안내문의 시각적 디자인화가 환자의 검사 이해도 및 정확성에 미치는 영향 평가)

  • Kang, Young-Eun;Jung, Woo-Young;Hong, Bo-Ruem
    • The Korean Journal of Nuclear Medicine Technology
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    • v.23 no.1
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    • pp.29-34
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    • 2019
  • Purpose An examination guide is a useful medium to provide the patient with an overview, pre- and post-test preparation, and precautions of nuclear testing. The design and arrangement of existing written texts and announcements were evaluated to elucidate the comprehension of patients undergoing testing. Materials and Methods Informational material describing bone scanning and $^{201}thallium$ myocardium perfusion single-photon emission computed tomography (SPECT), as a secondary examination, which accounts for the largest portion of gamma imaging at Asan Hospital (Seoul, South Korea), was selected as an improvement target in consultation with a national innovation center. Existing informational material was dispensed to patients scheduled for bone scans from November 2016 to February 2017 and the revised material was issued from March 2017 to May 2017. A survey was conducted of 200 patients who underwent $^{201}thallium$ myocardium perfusion SPECT before and after the revisions (n = 100 each time period) to assess the patients' understanding of the informational material. Results When comparing the use of the conventional vs. revised material, the number of patients who received treatment before bone scanning had decreased from 130 to 60, while the number of those who required additional imaging decreased from 53 to 14. Prior to the revision, 43% of patients underwent testing before preparation and 18% underwent additional testing. The decreased need for additional image acquisition after revision of the informational material resulted in a decrease in acquisition time of about 2 min, from 16.5 to 14.2 min. In the case of $^{201}thallium$ myocardium perfusion SPECT, patient comprehension of all five items surveyed had increased, while the number of patients who had repeatedly asked about various facets of the procedure pre- and post-testing had decreased from 36% to 16% and 31% to 14%, respectively. Conclusion Lower patient comprehension is accompanied by a decrease in image quality due to non-compliance during pre-testing and may lead to repetitive questions from the patient, which may also negatively affect the fatigue and work efficiency of the examiner. Improved readability and visibility of informational material through visualization was correlated with greater patient comprehension as well as improved image quality and acquisition time.

Cyclic Seismic Performance of RBS Weak-Axis Welded Moment Connections (RBS 약축 용접모멘트접합부의 내진성능 평가)

  • Lee, Cheol Ho;Jung, Jong Hyun;Kim, Sung Yong
    • Journal of Korean Society of Steel Construction
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    • v.27 no.6
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    • pp.513-523
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    • 2015
  • In steel moment frames constructed of H-shapes, strong-axis moment connections should be used for maximum structural efficiency if possible. And most of cyclic seismic testing, domestic and international, has been conducted for strong-axis moment connections and cyclic test data for weak-axis connections is quite limited. However, when perpendicular moment frames meet, weak-axis moment connections are also needed at the intersecting locations. Especially, both strong- and weak-axis moment connections have been frequently used in domestic practice. In this study, cyclic seismic performance of RBS (reduced beam section) weak-axis welded moment connections was experimentally investigated. Test specimens, designed according to the procedure proposed by Gilton and Uang (2002), performed well and developed an excellent plastic rotation capacity of 0.03 rad or higher, although a simplified sizing procedure for attaching the beam web to the shear plate in the form of C-shaped fillet weld was used. The test results of this study showed that the sharp corner of C-shaped fillet weld tends to be the origin of crack propagation due to stress concentration there and needs to be trimmed for the better weld shape. Different from strong-axis moment connections, due to the presence of weld access hole, a kind of CJP butt joint is formed between the beam flange and the horizontal continuity plate in weak-axis moment connections. When weld access hole is large, this butt joint can experience cyclic local buckling and subsequent low cycle fatigue fracture as observed in this testing program. Thus the size of web access hole at the butt joint should be minimized if possible. The recommended seismic detailing such as stickout, trimming, and thicker continuity plate for construction tolerance should be followed for design and fabrication of weak-axis welded moment connections.

Analysis Evaluation of Torsional Behavior of Hybrid Truss Bridge according to Connection Systems (격점구조형식에 따른 복합트러스교의 비틀림 거동 해석)

  • Choi, Ji-Hun;Jung, Kwang-Hoe;Kim, Tae-Kyun;Lee, Sang-Won;Kim, Jang-Ho Jay
    • Journal of the Korea Concrete Institute
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    • v.26 no.1
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    • pp.3-12
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    • 2014
  • Hybrid Truss Bridge (HTB) uses steel truss webs instead of concrete webs in prestressed box girder bridges, which is becoming popular due to its structural benefits such as relatively light self-weight and good aesthetics appearance. Since the core technology of this bridge is the connection system between concrete slabs and steel truss members, several connection systems were proposed and experimentally evaluated. Also, the selected joint system was applied to the real bride design and construction. The research was performed on the connection system, since it can affect the global behavior of this bridge such as flexural and fatigue behaviors as well as the local behavior around the connection region. The evaluation study showed that HTB applied to a curved bridge or an eccentrically loaded bridge had a weak torsional capacity compared to an ordinary PSC box girder bridge due to the open cross-sectional characteristic of HTB. Therefore, three types of girders with different joint system between truss web member and concrete slab were tested for their torsional capacity. In this study, the three different types of HTB girders under torsional loading were simulated using FEM analysis to investigate the torsional behavior of HTB girders more in detail. The results are discussed in detail in the paper.

Analysis of BWIM Signal Variation Due to Different Vehicle Travelling Conditions Using Field Measurement and Numerical Analysis (수치해석 및 현장계측을 통한 차량주행조건에 따른 BWIM 신호 변화 분석)

  • Lee, Jung-Whee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.24 no.1
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    • pp.79-85
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    • 2011
  • Bridge Weigh-in-Motion(BWIM) system calculates a travelling vehicle's weight without interruption of traffic flow by analyzing the signals that are acquired from various sensors installed in the bridge. BWIM system or data accumulated from the BWIM system can be utilized to development of updated live load model for highway bridge design, fatigue load model for estimation of remaining life of bridges, etc. Field test with moving trucks including various load cases should be performed to guarantee successful development of precise BWIM system. In this paper, a numerical simulation technique is adopted as an alternative or supplement to the vehicle traveling test that is indispensible but expensive in time and budget. The constructed numerical model is validated by comparison experimentally measured signal with numerically generated signal. Also vehicles with various dynamic characteristics and travelling conditions are considered in numerical simulation to investigate the variation of bridge responses. Considered parameters in the numerical study are vehicle velocity, natural frequency of the vehicle, height of entry bump, and lateral position of the vehicle. By analyzing the results, it is revealed that the lateral position and natural frequency of the vehicle should be considered to increase precision of developing BWIM system. Since generation of vehicle travelling signal by the numerical simulation technique costs much less than field test, a large number of test parameters can effectively be considered to validate the developed BWIM algorithm. Also, when artificial neural network technique is applied, voluminous data set required for training and testing of the neural network can be prepared by numerical generation. Consequently, proposed numerical simulation technique may contribute to improve precision and performance of BWIM systems.

Ground Test & Evaluation of Conformal Load-bearing Antenna Structure for Communication and Navigation (통신 항법용 다중대역 안테나 내장 스킨구조의 지상시험평가)

  • Kim, Min-Sung;Park, Chan-Yik;Cho, Chang-Min;Jun, Seung-Moon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.11
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    • pp.891-899
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    • 2013
  • This paper suggests a test and evaluation procedure of conformal load-bearing antenna structure(CLAS) for high speed military jet application. A log periodic patch type antenna was designed for multi-band communication and navigation antenna. Carbon/Glass fiber reinforced polymer was used as a structure supporting aerodynamic loads and honeycomb layer was used to improve antenna performance. Multi-layers were stacked and cured in a hot temperature oven. Gain, VSWR and polarization pattern of CLAS were measured using anechoic chamber within 0.15~2.0 GHz frequency range. Tension, shear, fatigue and impact load test were performed to evaluate structural strength of CLAS. Antenna performance test after every structural strength test was conducted to check the effect of structural test to antenna performance. After the application of new test and evaluation procedure to validate a new CLAS, a design improvement was found.

Numerical Study on the Strength Safety of High Pressure Gas Cylinder (고압가스 압력용기의 강도안전성에 관한 수치해석적 연구)

  • Kim, Chung-Kyun;Kim, Seung-Chul
    • Journal of the Korean Institute of Gas
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    • v.14 no.2
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    • pp.1-6
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    • 2010
  • The strength safety of high pressure gas cylinder has been analyzed by using a finite element method. In this study, the internal gas pressures of a steel bombe include a service charging pressure of $9kg/cm^2$, high limit charging pressure of $18.6kg/cm^2$, high limit of safety valve operation pressure $24.5kg/cm^2$, and hydraulic testing pressure of $34.5kg/cm^2$. The computed FEM results indicate that the strength safety for a service charging pressure of $9kg/cm^2$ and high limit charging pressure of $18.6kg/cm^2$ is safe because the stress of a gas cylinder is within yield strength of steel. But the stress for a hydraulic testing pressure of $34.5kg/cm^2$ sufficiently exceeds the yield strength and remains under the tensile strength. If the hydraulic testing pressures frequently apply to the gas cylinder, the bombe may be fractured because a fatigue residual stress is accumulated on the lower round end plate due to a plastic deformation. The computed results show that the concentrated force in which is applied on a skirt zone does not affect to the lower round end plate, and the most weak zone of a bombe is a middle part of a lower round end plate between a bombe body and a skirt for a gas pressure. Thus, the FEM results show that the profile of a lower round end plate is an important design parameter of a high pressure gas cylinder.