• Title/Summary/Keyword: fatigue Model

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Behavior of Tension Clamp in Rail Fastening System (레일 체결장치 텐션클램프의 거동)

  • Choi, Shin-Hyung;Park, Beom-Ho;Yun, Kyung-Min;Bae, Hyun-Ung;Lim, Nam-Hyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.12
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    • pp.8812-8819
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    • 2015
  • In a situation in which importance of rail fastening system is growing with increasing the construction of concrete track, an accident of tension clamp(the component of rail fastening system) breaking has been recently occurred. This results from various factors such as field condition, operating agency, running condition, traffic frequency and so on. Thus, the study for the behavior of tension clamp is required. In this paper, an experiment and finite element analysis(FEA) have been performed to analyse the mechanical behavior of tension clamp. The stress and displacement of tension clamp have been analyzed as the clamping force through a laboratory test, and they were compared with FEA results. Furthermore, the stress and displacement of the tension clamp are derived from train load condition applying the verified model, and the fatigue vulnerability of the tension clamp is identified through stress analysis.

Relational Analysis between Family support, Knowledge, Self-efficacy, Syndrome and Physical disability of Fibromyalgia Patients (섬유조직염 환자의 가족지지, 지식, 자기효능감, 증후 및 신체활동장애 간의 관계분석)

  • Han, Sang-Sook;Kang, Hyun-Sook
    • Journal of muscle and joint health
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    • v.5 no.2
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    • pp.191-205
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    • 1998
  • This study was conducted to identify the relations between the factors influencing syndrome and physical disability of fibromyalgia patients. The subjects of this study were 125 outpatients selected at H. Rheumatism clinic from February to July in 1997, The Collected data were analyzed by Frequency, Pearson correlation using SPSS Windows and Path analysis using LISREL 7.16. The results were as follows. 1. General characteristics of subjects About 2/3 of subjects were over 40years of age and most of them were graduated from high school. The Christian were over a half (54.0%) of subjects. 2. Correlation between Family support, knowledge, Self-efficacy, Syndrome and physical disability. As knowledge was positively related to self-efficacy(r=.306), the family support was positively related to self-efficacy(r=.217), and family support was negatively to syndrome. Self-efficacy showed negative relation with syndrome and Physical disability. Syndrome as physical disability represent positive relation. Therefore all hypotheses were supported. 3. Causal relations between research variables. Family support influenced on syndrome, as syndrome on physical activity, as well as knowledge on self-efficacy & physical disability. The model also showed a good fit to the data[$X^2$=1.21 df=1(p=.546), GFI=.996, AGFI=.971, RMSR=.023]. 4. Correlation between symptoms of Fibromyalyia. Having analyzed the relations between tender point, pain, stiffness, functional disturbance, sleep disturbance, depression, fatigue, anxiety, the results were as follows ; All relations show statistically positive correlation, which means close relationship between symptoms, except between pain and depression, pain and anxiety. As a result, symptoms of Fibromyalgia had close relation. Therefore, these were common, rather than individual symptoms. This syndrome influenced on physical disability, and self-efficacy on the both, as knowledge on self-efficacy. In conclusion, to improve syndrome relief and physical disability of fibromyalgia, nursing interventions such as education, self-efficacy increasing stratagy, and family counseling are needed.

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Acute Health Effects of the Hebei Oil Spill on the Residents of Taean, Korea (허베이 스피리트호 유류유출사고 지역주민의 급성건강영향)

  • Lee, Cheol-Heon;Kang, Young-A;Chang, Kyu-Jin;Kim, Chang-Hoon;Hur, Jong-Il;Kim, Jae-Youn;Lee, Jong-Koo
    • Journal of Preventive Medicine and Public Health
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    • v.43 no.2
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    • pp.166-173
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    • 2010
  • Objectives: On December 7, 2007, the Hebei Spirit oil tanker spilled out 12,547 kl of crude oil on the Yellow Sea 10 km away from the cost of Taean Province, Korea. As the coastline has been contaminated, local residents have been exposed to crude oil. Because the residents were showing many symptoms, we investigated the acute health effects of this oil spill on them. Methods: We conducted a cross-sectional study consisting of the heavy and moderately oil soaked area in Taean and the lightly oil soaked area in Seocheon. Ten seashore villages were selected from each area, and 10 male and female adults were selected from each village. We interviewed the subjects using a structured questionnaire on the characteristics of residents, the cleanup activities, the perception of oil hazard, depression and anxiety, and the physical symptoms. The odds ratios and 95% confidence intervals were analyzed using logistic regression analysis. The logistic regression model was adjusted for age, gender, education, smoking, the perception of oil hazard and anxiousness. Results: The more highly contaminated the area, the more likely it was for residents to be engaged in cleanup activities and have a greater chance of exposure to oil. The indexes of anxiety and depression were higher in the heavy and moderately oil soaked areas. The increased risks of headache, nausea, dizziness, fatigue, tingling of limb, hot flushing, sore throat, cough, runny nose, shortness of breath, itchy skin, rash, and sore eyes were significant. Conclusions: The results suggest that exposure to crude oil is associated with various acute physical symptoms. Long-term investigation is required to monitor the residents' health.

Effect of Heat Processed Ginseng on Anti-Fatigue (가공 인상의 항피로효과)

  • Shin, Y.W.;Choi, H.J.;Kim, D.H.;Park, J.H.;Kim, N.J.
    • Korean Journal of Pharmacognosy
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    • v.37 no.4 s.147
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    • pp.246-252
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    • 2006
  • Processing of traditional herbal medicine is one of the pharmaceutical technique in oriental medicine. Most frequently used processing method in oriental medicine are roasting and steaming. In this studies, to elucidate the pharmacological transformation of traditional herbal medicine by means of processing them, Ginseng Radix (root of Panax ginseng, Araliaceae) was used as a sample. Processed ginseng radix (SGR, Sun Ginseng) was prepared by steaming of roots of white ginseng (GR) for 3 hours at $120^{\circ}C$. The biological activities of methanol extract of GR and SGR were investigated. According to DPPH radical scavenging effects, and inhibitory effects of xanthine oxidase and AAPH induced hemolysis, PGR exhibited more effective than those of GR in vitro. And, the antifatigue effect of GR and SGR were investigated using a weight-loading forced swimming test by monitoring swimming times and prolonged intensity exercise model rats by measuring blood biochemical parameters. GR and SGR were significantly prolonged swimming times in 8% body weight ratio loaded mice. Also, they had the inhibitory effects on the decrease of blood glucose levels, the elevation of serum creatinine, lactic acid and free fatty acid, and lactic dehydrogenase activities in forces swimming rats with 1% of the body weight attached to the neck for 3 hours. SGR was more excellent than GR on these effect. Also, these effects were transformed to the n-butanol fraction of methanol extract of SGR. From these results, it can be considered that SGR has antifatigue effect.

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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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.

Stacking Sequence Design of Fiber-Metal Laminate Composites for Maximum Strength (강도를 고려한 섬유-금속 적층 복합재료의 최적설계)

  • 남현욱;박지훈;황운봉;김광수;한경섭
    • Composites Research
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    • v.12 no.4
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    • pp.42-54
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    • 1999
  • FMLC(Fiber-Metal Laminate Composites) is a new structural material combining thin metal laminate with adhesive fiber prepreg, it nearly include all the advantage of metallic materials, for example: good plasticity, impact resistance, processibility, light weight and excellent fatigue properties. This research studied the optimum design of the FMLC subject to various loading conditions using genetic algorithm. The finite element method based on the shear deformation theory was used for the analysis of FMLC. Tasi-Hill failure criterion and Miser yield criterion were taken as fitness functions of the fiber prepreg and the metal laminate, respectively. The design variables were fiber orientation angles. In genetic algorithm, the tournament selection and the uniform crossover method were used. The elitist model was also used to be effective evolution strategy and the creeping random search method was adopted in order to approach a solution with high accuracy. Optimization results were given for various loading conditions and compared with CFRP(Carbon Fiber Reinforced Plastic). The results show that the FMLC is more excellent than the CFRP in point and uniform loading conditions and it is more stable to unexpected loading because the deviation of failure index is smaller than that of CFRP.

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Crystallographic Characterization of the (Bi, La)4Ti3O12 Film by High-Resolution Electron Microscopy (고분해능 전자현미경법을 이용한 (Bi, La)4Ti3O12 박막의 결정학적 특성 평가)

  • Lee, Doek-Won;Yang, Jun-Mo;Park, Tae-Su;Kim, Nam-Kyung;Yeom, Seung-Jin;Park, Ju-Chul;Lee, Soun-Young;Park, Sung-Wook
    • Korean Journal of Materials Research
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    • v.13 no.7
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    • pp.478-483
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    • 2003
  • The crystallographic characteristics of the $(Bi, La)_4$$Ti_3$$O_{12}$ thin film, which is considered as an applicable dielectrics in the ferroelectric RAM device due to a low crystallization temperature and a good fatigue property, were investigated at the atomic scale by high resolution transmission electron microscopy and the high resolution Z-contrast technique. The analysis showed that a (00c) preferred orientation and a crystallization of the film were enhanced with the diffraction intensity increase of the (006) and (008) plane as the annealing temperature increased. It indicated a change of the atomic arrangement in the (00c) plane. Stacking faults on the (00c) plane were also observed. Through the comparison of the high-resolution Z-contrast image and the $Bi_4$$Ti_3$$O_{12}$ atomic model, it was evaluated that the intensity of the Bi atom was different according to the atomic plane, and it was attributed to a substitution of La atom for Bi at the specific atom position.

Predictors of Blood and Body Fluid Exposure and Mediating Effects of Infection Prevention Behavior in Shift-Working Nurses: Application of Analysis Method for Zero-Inflated Count Data (교대근무 간호사의 혈액과 체액 노출 사고 예측 요인과 감염예방행위의 매개효과: 영과잉 가산 자료 분석방법을 적용하여)

  • Ryu, Jae Geum;Choi-Kwon, Smi
    • Journal of Korean Academy of Nursing
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    • v.50 no.5
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    • pp.658-670
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    • 2020
  • Purpose: This study aimed to identify the predictors of blood and body fluid exposure (BBFE) in multifaceted individual (sleep disturbance and fatigue), occupational (occupational stress), and organizational (hospital safety climate) factors, as well as infection prevention behavior. We also aimed to test the mediating effect of infection prevention behavior in relation to multifaceted factors and the frequency of BBFE. Methods: This study was based on a secondary data analysis, using data of 246 nurses from the Shift Work Nurses' Health and Turnover study. Based on the characteristics of zero-inflated and over-dispersed count data of frequencies of BBFE, the data were analyzed to calculate zero-inflated negative binomial regression within a generalized linear model and to test the mediating effect using SPSS 25.0, Stata 14.1, and PROCESS macro. Results: We found that the frequency of BBFE increased in subjects with disturbed sleep (IRR = 1.87, p = .049), and the probability of non-BBFE increased in subjects showing higher infection prevention behavior (IRR = 15.05, p = .006) and a hospital safety climate (IRR = 28.46, p = .018). We also found that infection prevention behavior had mediating effects on the occupational stress-BBFE and hospital safety climate-BBFE relationships. Conclusion: Sleep disturbance is an important risk factor related to frequency of BBFE, whereas preventive factors are infection prevention behavior and hospital safety climate. We suggest individual and systemic efforts to improve sleep, occupational stress, and hospital safety climate to prevent BBFE occurrence.