• Title/Summary/Keyword: Repetitive impact

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The Impact on the Musculoskeletal Symptoms of the Warehouse Employees's Work-related Characteristics and Job Stress (물류창고 종사원의 작업 관련 특성과 직무 스트레스가 근골격계 자각증상에 미치는 영향)

  • Lee, Jin-Hee;Jung, Hye-Sun;Lee, Hyun-Ju
    • Korean Journal of Occupational Health Nursing
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    • v.26 no.3
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    • pp.133-141
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    • 2017
  • Purpose: The purpose of this study was to identify the relationship between work-related characteristics and job stressors and the factors influencing musculoskeletal symptoms of the warehouse employees. Methods: The research was a cross-sectional, descriptive study. Data were collected from 319 warehouse employees who agreed to participate in the study by using self-report questionnaires. Data were analyzed using descriptive statistics, $x^2-test$, and logistic regression analysis (SPSS 18.0). Results: The overall prevalence of musculoskeletal symptoms was 37.6%. The logistic regression analysis revealed a posture that renders fatigue or pain, repetitive work, and a higher total score of job stressors as the risk factors for musculoskeletal symptoms in many body parts. Conclusion: Employers should plan to educate employees who work in warehouses about the correct working posture to prevent musculoskeletal diseases, stop repetitive work, and manage job stressors.

Evaluation of Effects on Impact Resonance Test for Determining Modulus of Asphalt Concrete (아스팔트 콘크리트 탄성계수 결정을 위한 충격공진시험 영향요소 평가)

  • Kweon, Gi-Chul;Lee, Jae-Hoan
    • International Journal of Highway Engineering
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    • v.9 no.2 s.32
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    • pp.89-99
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    • 2007
  • The stiffness of the asphalt concrete is represented by the complex modulus $E^*$, which is very important properties in the mechanistic design of flexible pavement system. The moduli of asphalt concrete were generally determined by dynamic modulus test. However, the dynamic modulus testing method is too complex, expensive, and time consuming to be applicable on a production basis. The IR(Impact Resonance) method has been shown to be a truly simple nondestructive testing method which produces very repetitive, consistent results. The major object of this study was to estimate of the effects on IR tests for determining modulus of asphalt concrete including impact position, specimen support condition, impact steel ball size and sampling rate. The variations of IR test results with various testing conditions are within ${\pm}2.7%$.

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A Study on Crash Analysis of Vehicle and Guardrail using a LS-DYNA Program (LS-DYNA 프로그램을 이용한 차량과 가드레일의 충돌해석에 관한 연구)

  • Kwon, O-Hyun;Baek, Se-Ryong;Yoon, Jun-Kyu;Lim, Jong-Han
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.3
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    • pp.179-186
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    • 2016
  • A study is to research crash barriers for vehicles that prevent road breakaway of vehicles and protect car passengers and pedestrians as absorbing impulse. Protection performance tests on vehicle passengers were simulated by using a LS-DYNA program. Through repetitive simulation on various speed and angles, passenger protection performance according to different impact condition was contemplated. Variable setting for the simulation was calculated as the mean weight of domestic car sales. By analyzing NASS (National Automotive Sampling System) of NHTSA (National Highway Traffic Safety Administration) of the U.S., the actual speed and collision angle section of accidents were computed. As a result, we confirmed that THIV (Theoretical Head Impact Velocity) and PHD (Post-impact Head Deceleration) are increased according to the impact speed and angle. Also, when the vehicle hit the guardrail post, we could be confirmed that the passenger protection performance greatly decreased.

Impact of Korean Workers' Experience of Exposure to the Physical Work Factors on Absence

  • Choi, Seo-Yeon;Lee, Seong-Jin
    • Journal of the Korea Society of Computer and Information
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    • v.22 no.6
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    • pp.149-156
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    • 2017
  • In this paper, we propose to enhance a Physical working conditions to decrease absence from work. we demonstrated the correlation of worker's absence with various environmental factors in workplace by surveying 6,962 workers. As result, first, concerning exposure to physical work factors, most of them complained of vibration, and concerning exposure to improper working posture, most of them complained of repetitive arm and hand motions. Second, the absence experience had correlations with age, monthly income, smoking, number of employees, long term working, and shift work, and of the physical factors, hand vibration, noise, high temperature, low temperature and improper working posture had correlations with physical pain posture, movement of people and carrying heavy materials. Third, experience of exposure to hand vibration, noise and low temperature of the physical factors had impact on absence, and of the improper working posture, physical pain posture and carrying heavy stuff had impacts on absence. Through this study, it was found that of the work factors of Korean workers, physical factors and improper working posture had impacts on absence. The results of this study confirmed that physical factors and inappropriate working posture among work factors influenced the absenteeism. Therefore, it is required to improve the work environment regarding physical risk factors and prepare a systematic management plan.

Correlation Analysis between Kinematic Variables and Ground Slope Perception Ability during Golf Putting (골프 퍼팅 시 운동학적 변인과 경사도 인지능력 간 상관성 분석)

  • Lee, Jae-Woo;Im, Young-Tae;Kwon, Moon-Seok;Park, Jun-Sung
    • Journal of the Korean Applied Science and Technology
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    • v.38 no.3
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    • pp.727-734
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    • 2021
  • The purpose of this study was to analyze correlation between kinematic variables and ground slope perception ability during golf putting. 16 collegiate golfers were participated. To collect and analyze the kinematic data of putter head, SAMPutt lab was used(70 Hz). It was performed Pearson's correlation analysis using SPSS. The level of significance was at .05. As a results, right was correlated with backswing in flat. Toe-up was correlated with follow-through and left was correlated with aim, backswing, impact, follow-through, and loft in slice 1°. Toe-down was correlated with aim, backswing, impact in slice 2°. Toe-up was correlated with follow-through in hook 2°. In conclusion, it is important to improve the putting stroke through repetitive ground slope perception training.

Experimental investigation of slamming impact acted on flat bottom bodies and cumulative damage

  • Shin, Hyunkyoung;Seo, Byoungcheon;Cho, Sang-Rai
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.10 no.3
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    • pp.294-306
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    • 2018
  • Most offshore structures including offshore wind turbines, ships, etc. suffer from the impulsive pressure loads due to slamming phenomena in rough waves. The effects of elasticity & plasticity on such slamming loads are investigated through wet free drop test results of several steel unstiffened flat bottom bodies in the rectangular water tank. Also, their cumulative deformations by consecutively repetitive free drops from 1000 mm to 2000 mm in height are measured.

Safety Estimation of the Carbon/Carbon Brake Disk Having Crack by Experimental/Analytical Method (크랙이 존재하는 탄소/탄소 브레이크 디스크의 실험적/해석적 안정성 판별)

  • 오세희;유재석;김천곤;홍창선;박종현
    • Composites Research
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    • v.15 no.2
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    • pp.24-31
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    • 2002
  • In this paper, the safety of the crack existing between the load bearing part and the friction part in key slots was evaluated. The repetitive loading test considered impact damage was performed for the various crack models. Also, the probability of the crack propagation and the stress concentration at the crack tip were studied by using a FE analysis. By these method, safety of the disk was confirmed.

An Alternative Fiber Processing Method

  • Seo, Yung-Bum;Lee, Chun-Han
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.43 no.5
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    • pp.34-42
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    • 2011
  • A fiber processing method, which might be an alternative for conventional refining process, was introduced. The method consists of repetitive, gentle, mechanical impacts on fibers, followed by fiber uncurling process. This method was very effective for OCC and BCTMP for increasing WRVs (water retention value) while keeping fiber lengths from shortening. For OCC and BCTMP, gentle mechanical impacts on fibers using Hobart mixer increased breaking lengths and tear strengths simultaneously at fast drainage level, and straightening fibers using kady mill increased those strength properties further. For SwBKP and HwBKP, only mechanical impacts using the Hobart mixer were effective on increasing tensile and tear strength at fast drainage, but there were no further increase by kady mill treatment. The strength increases of BCTMP by this alternative fiber processing method were exceptionally high. An extensive engineering development should be followed to actualize this fiber processing mechanism in an energy-effect way.

Lesion development and functional recovery after spinal cord injury (척수 손상 후 병변의 발달과 기능의 회복)

  • Jun Kyong-hee;Park Rae-Joon
    • The Journal of Korean Physical Therapy
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    • v.14 no.4
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    • pp.441-453
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    • 2002
  • The purpose of this study was to characterize lesion development, neural plasticity, and motor learing after spinal cord injury. Facilitatory intervention such as weight bearing and locomotor training after SCI may be more effective than compensatory strategies at inducing neuroplasticity and motor recovery. Minimal tissue sparing has a profound impact on segmental systems and recovery of function Spinal animal could functional locomotion when subjected to repetitive stimulation. task-specific learning of isolated lumbar spinal could improve motor performance more then other task learning.

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A Study on the Interior Architectural Characteristic of Dutch Structuralism (네덜란드 구조주의 건축의 실내공간 특성에 관한 연구)

  • 정미현;김문덕
    • Proceedings of the Korean Institute of Interior Design Conference
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    • 2001.05a
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    • pp.64-68
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    • 2001
  • As Dutch structuralism discovered a possibility that can improve the problem of modem architecture through study on non-western area. Dutch structuralism had tremendous impact on Philosophy, psychology, art history and the style of a dress and many other cultural trend. In architecture, Aldo van Eyck embodied that theory and succeeded to Herman Hertzberger and Piet Blom. As result Structuralism related with architecture has dealt with the participation and domain of residents, namely public domain and private domain, the approach property of public space, middle domain which shows the harmony between public domain and private one, and the structuralism discovered that each element of public space and private space has been developed as an architectural type that makes a group by repetitive arrangement and it found out a possibility that can make up problems overlooked in modem architecture through development and change.

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