• Title/Summary/Keyword: Fatigue Life

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A Study on Verification of the Profile of Mood States(POMS) for Korean Elders (노인의 기분측정을 위한 도구(Profile of Mood States, POMS)의 타당화에 관한 연구)

  • 신윤희
    • Journal of Korean Academy of Nursing
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    • v.26 no.4
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    • pp.743-758
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    • 1996
  • This paper was done to verify the use of the Profile of Mood States (POMS) which was developed by McNair, Lorr, and Droppleman(1992) with modifications so that it is appropriate for Korean elders. Through the modified tool, it is possible to examine the mood of Korean elders and to contribute to the welfare of elders. The subjects were 370 elderly persons over 60 years old and the data for 319 persons(86%) were analyzed. The research tool was the POMS translated by Yun(1993) and corrected by the researcher. Data were collected between February 12 and April 9 in 1996 and analyzed using the SAS package. The result are as follows 1. Items with low Cronbach coefficient alpha which means low correlation with total items were removed. The items were removed : friendly, tense, considerate, relaxed, sympathetic, resentful, good-natured, rebellious, trusting, carefree. 2. Overlapped or ambiguous items were discussed by colleagues and elders through verification of con-tent-validity and were removed. Five items were removed in tense-anxiety, seven, in depression-dejection, three, in vigor-activity, three, in fatigue-inertia, two, in confusion-bewilder-ment, five, in friendliness, and six, in anger-hostility. Thirty four items remainined : angry, clear-headed, lively, confused, sorry, shaky, list-less, peeved, sad, active, blue, hopeless, spiteful, uneasy, unable to concentrate, fatigued, helpful, nervous, lonely, cheerful, bitter, exhausted, anxious, ready to fight, sluggish, helpless, alert, deceived, efficient, worthless, forgetful, terrified, vigorous, and uncertain about things. 3. Factor analysis was done in order to confirm construct validity and three factors were obtained from the result. The first factor, 'anxiety-depression' included 21 items, the second factor, 'vigor' included eight items, and the third factor, 'anger' included five items. Cronbach coefficient alpha for the 34 items was. 95. Based on the result, the following is suggested : 1. a contribute to elder's welfare can be made by examining Korean elder's mood in life. 2. there is a need to develop tools appropriate to Korean culture which can be used to examine elders' mood. 3. The modified POMS tool needs to be reverified with appropriate age groups and settings.

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Effect of Surface Profiles on Pavement Fatigue Life (포장 프로파일이 포장 피로수명에 미치는 영향 분석)

  • Park, Dae-Wook;An, Deok-Soon;Kwon, Soo-Ahn
    • International Journal of Highway Engineering
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    • v.11 no.2
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    • pp.167-174
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    • 2009
  • The simulation of dynamic load was conducted based on surface profile on asphalt concrete pavement, vehicle speeds, and suspension types using a truck simulation program. The results of the simulated dynamic load based on different surface profile, vehicle speeds, and suspension types are analyzed. As pavement roughness and vehicle speed are increased, the dynamic load was increased. Walking beam suspension produces greater dynamic load than air spring suspension. Pavement damage index is calculated based on covariance of dynamic load and Paris-Erdogan fracture parameter, n which is based on creep compliance tests of asphalt mixtures used in Korea. The higher covariance of dynamic load, confidence level, and fracture parameter are used, the greater pavement damage index is obtained. Specification of pavement roughness can be developed in various vehicle speeds and asphalt mixtures, and pay factor can be determined after constructing asphalt concrete pavement using pavement damage concepts.

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New Weight-reduction Design of the Fifth Wheel Coupler with a Trailer by Using Topology Optimization and Durability Tests (위상최적설계를 통한 트레일러 제5차륜 연결구조물의 경량화 및 내구성)

  • Kim, Cheol;Lee, Seung-Yoon;Lee, Yong-Choon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.2
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    • pp.137-143
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    • 2016
  • The fifth wheel coupler is a heavy automotive coupling structure which connects a tractor and a trailer used for heavy-duty trucks widely. It is subjected to various loads simultaneously such as rolling, pitching and yawing loads as well as coupling frictional and impact loadings. Most of existing couplers have been overdesigned and, therefore, it is necessary to reduce the dead weight to increase the fuel efficiency. The topology optimization was applied in order to find conceptual layout designs which could show major load paths and ribs locations, and then the size structural optimization was performed in order to determine the heights and thicknesses of coupler ribs with the predetermined various loading conditions for the development of a new slim coupler with a minimum weight and high enough strength and stiffness. As the results of the topology optimum design, an efficient new coupling structure for truck trailers was designed. The weight of the new fifth wheel coupler was reduced by 4.9 %, compared with the existing one, even though all strength requirements were satisfied. The fatigue test of the new coupler was performed with cyclic vertical loads (+78.4 to +235.2 kN) and horizontal loads (-91.2 to +91.2 kN) simultaneously at 1 Hz and the life of 2,000,000 cycles were achieved without failure.

Development and validation of an instrument to measure the health status of healthy but unsatisfied people : Mibyeong index(未病 index) (이상증상 기반 미병 분류도구의 신뢰도 및 타당도 연구)

  • Lee, Youngseop;Baek, Younghwa;Park, Kihyun;Jin, Hee-Jeong;Lee, Siwoo
    • Journal of Society of Preventive Korean Medicine
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    • v.20 no.3
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    • pp.45-53
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    • 2016
  • Objectives : The number of people in Mibyeong state that complain of physical and mental discomfort but without a clear medical diagnosis has rapidly increased, but the conventional medical system is insufficient to care for these people. By establishing an evaluation instrument for Mibyeong state, it will be possible to provide a research base for Mibyeong management system and expand the clinical area of integrative medicine. Methods : Mibyeong Index was designed to measure inconvenience and resilience of subject's complains including four physical symptoms (fatigue, pain, low sleep quality, indigestion) and mental distress include anxiety, anger, depression. A 21-item quality of healthy measure was developed and tested. We used results of a nation-wide stratified sampled adult data in Korea. Results and Conclusions : Mibyeong index had adequate internal consistency, Cronbach's alpha was 0.88 in general population(N=1,110). The correlation between establised quality of life questionnaires (including SF-12 and EQ-D5 VAS) and the Mibyeong index were from 0.468 to 0.493. The national promotion of advanced health for an aging society and original Mibyeong care technology based on traditional Korean medicine can be developed by a self-care system that enhancing health before suffering illness. We expect that this instrument could be contribute to health management of people in Mibyeong state.

Study on the Base and Subbase Method of Agricultural Road -On the Resilient Modulus Characteristics of the Subgrade and Cement Treated Base- (농도의 기층 및 보조기층 공법연구 -노상 및 시멘트 안정 처리층의 Mr 특성을 중심으로-)

  • 도덕현
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.31 no.2
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    • pp.66-81
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    • 1989
  • The characteristics of resilient modulus(Mr) which dominates the life of pavement and the design of pavement were investigated on the test specimens which were cement treated and non-treated of the three different soil types. The results are summarized as follows : 1. The resilient modulus was decreased by increasing the cyclic deviator stress ($\sigma$d) , especially the resilient modulus was gradually decreased or sometimes increased when the value of ad was greater than 0.75- 1. 0kg/cm$^2$. 2. The resilient modulus was increased by increasing the homogeneous confined stress ($\sigma$do) and such phenomena were distinct on the coarse soils. 3. The resilient modulus was increased by increasing the ratio of confined stress(Kc), and this phenomena were eminent on the coarse soils too, and the higher permanent strain was showed by increasing the value of Kc. 4. In the drained cyclic triaxial compression test, the value of ad, Kc, and (Oho) was introduced by the following interrelated equations which were similar to the Mr model of Cole. Kcn/Mr=K1(J$_2$/ $\tau$oct)K2 ............. (coarse soli) Mcn/Mr=K3($\sigma$dp/ $\tau$f)k4 ...............(fine soils) 5. The stress path was not much affected by the value of Mr, however, moisture content, dry desity, and contant of fines affected the value of Mr. 6. In the soil-cement specimens, the resilient compression strain($\varepsilon$d) was decreased by the increment of the $\sigma$ho, and Mr was decreased by increasing the $\sigma$d 7. In the flexible pavement. the cement treated layer should be designed not to fail by the fatigue before the designed traffic load, and actually the pavement could cover the traffic load to a certain extent under the post-crack phase, therefore farther studies on this phenomena' are required in the design analysis. 8. The finite element computer program (ANALYS) was used for displacement analysis of pavement containing the cement-treated layer, The result showed that the program used for this analysis was proved to be usable.

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Workers' Health Belief in Health Promotion Programs and Related Factors (사업장 건강증진 프로그램에 대한 근로자의 건강신념 및 관련요인)

  • Kim, Young-Im;Kim, Soon-Lae;Jung, Hye-Sun;Kim, Souk-Young;Park, Hyun-Ju
    • Research in Community and Public Health Nursing
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    • v.20 no.4
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    • pp.465-473
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    • 2009
  • Purpose: The purpose of the study was to investigate the relationships between worker's health belief in health promotion programs and their demographic, health, and health behavior characteristics. Methods: This study used survey data from 262 small- and large-scale workplaces. The study included 1149 male and female workers who completed the questionnaires. Results: The health belief score increased significantly with age and length of service. Male, married, shift-work, and white-collar workers showed a significantly higher health belief score than female, single, non-shift-work, and blue-collar ones. Workers with disease history, hypertension, or obesity had a significantly higher health belief score. Regular exercise was significantly correlated with the health belief score. When all the variables were included in the model, the health belief score was significantly higher in workers who were married, had a longer length of service, worked in the sales department, were diagnosed with hypertension, exercised regularly, and felt fatigue. Conclusion: The results showed that workplace intervention programs meet more the needs of workers who have a higher health belief score. In addition, given that healthier life style was related to a higher health belief score, further research is required to find how to change health behavior in workers.

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Study on Residual Stress Distribution in Thick Plate Welded Material Using Indentation Equipment (압입시험기를 이용한 후판용접재의 잔류응력 분포에 관한 연구)

  • Huh, Sun-Chul;Kim, Gwi-Nam;Lee, Jong-Seok;Park, Cheol-Hong;Park, Joun-Sung;Park, Won-Jo
    • Journal of Ocean Engineering and Technology
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    • v.25 no.6
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    • pp.66-71
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    • 2011
  • Recently, the production of shipbuilding and offshore plant industries, with a trend toward large structures, has led to an increased use of high strength ultra-thick plates. The use of ultra-thick plates increases the welding tasks, and the welding process generates distortion and residual stress in the weldment because of the rapid heating and cooling. Welding distortion and residual stress in the welded structure resulte in many troubles such as deformation and life deterioration. In particular, the welding residual stress has an important effect on welding deformation, fatigue, buckling strength, brittleness, etc. The purpose of this study was to evaluate the residual stress at a multi-pass weldment using an experimental method for EH36 high-tension steel. In this experimental method, AIS3000 was used to measure the residual stress of a welded part, HAZ, and base metal; EPMA and XRD were used to study the material properties.

Enhancement of Sleep Environment Using Sensor (센서를 이용한 수면환경 개선)

  • Shin, Seong-Yoon;Shin, Kwang-Seong;Rhee, Yang-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.11
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    • pp.2485-2490
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    • 2010
  • In this paper, gather the sleep environment data of bedroom to sleeping and analyze the relationship between the obtained conditional data and the sleep. Based on this, system provide the optimal sleep environment of individual person by extracting the simulation model. The experiments of system was using H-MOTE2420 sensor composed of temperature/humidity sensor and ambient light sensors. We use difference image method in motion extraction from video for extraction of tossing and turning. In addition, it was entered such as ratio of fatigue, ratio of drinking, ratio of empty stomach as the information of weight can affect to sleep. Resultingly of experience, we can extract the optimal sleep environment. From now on, we will try to enhance to help to lead more pleasant daily life providing proper indoor environment changes depending on the situation even a partial of organic living environments such as eating and work as well as special sleep circumstances.

Evaluation of Healing Properties of Asphalt Mixtures (아스팔트 혼합물의 손상회복 특성 평가)

  • Kim, Boo-Il
    • International Journal of Highway Engineering
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    • v.7 no.2 s.24
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    • pp.69-76
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    • 2005
  • While the repeated traffic loading accumulates the damage of asphalt pavement, the damage has being healed during rest periods. And then, this healing enhances the fatigue life of asphalt pavement. A method was developed to determine the healing rate of asphalt mixture in terms of recovered dissipated creep strain energy (DCSE) per unit time, and the healing properties of four different asphalt mixtures were evaluated. The test procedure consists of repeated loading test and periodical resilient modulus tests. A normalized healing rate in terms of $DCSE/DCSE_{applied}$ was defined to evaluate the healing properties independently of the amount of damage incurred in the mixture. From the test results, it was concluded that the healing rates of asphalt mixtures were increased exponentially as the temperature was increased and more affected by the structural characteristics of mixture such as asphalt content than the binder characteristics such as the polymer modification.

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A Study on the Structural Integrity Considering the Installation of a Micro-tube Heat Exchanger (미세튜브 열교환기의 장착을 고려한 구조건전성에 관한 연구)

  • Oh, Se Yun;Kim, Tae Jin;Cho, Jong Rae;Jeong, Ho Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.4
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    • pp.447-451
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    • 2015
  • The objective of this study is to predict the structural characteristics of a heat exchanger mounted on an aircraft engine using finite element analysis. The plastic fracture and life of the heat exchanger were estimated by a thermo-mechanical analysis. Tensile tests were conducted under high temperature conditions (700, 800, 900, 1000 K) using five specimens to obtain the mechanical properties of the Inconel 625 tubes. To assess the structural characteristics of the heat exchanger, the full and partial models were applied under the operating conditions given by the thermo-mechanical and inertial load. As a result, the case, tubesheet, flange, and mounting components have a reasonable safety margin to the allowable stress assuming a fatigue strength of Inconel 625 of 10000 cycles under 1000 K.