• Title/Summary/Keyword: fatigue behaviors

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An Inquiry to the Causal Perceptions & Health Seeking Behaviors of Rheumatoid Arthritis Patients

  • Kim, Boon-Han;Kim, Hung-Kyu;Yun Jung;Kang, Hwa-Jeong
    • Journal of Korean Academy of Nursing
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    • v.29 no.5
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    • pp.1001-1010
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    • 1999
  • This study was undertaken to investigate the causal perceptions and health seeking behaviors of Rheumatoid arthritis patients, define and understand the typology, and find the relationship between causal perceptions and health seeking behavioral types. There were six types(Physical Fatigue, Dispensation of Nature, Causality to Environment, Conscience of Guilty, Rationally perceiving, Psychological Stress) of subjective opinion about Causal Perceptions of Rheumatoid Arthritis Patients. And there were four types(Oriental medical Treatment, Information Seeking, Dietary Control. Western Medical Treatment) of subjective opinion about Health Seeking Behaviors. In the relationship between types of the causal perceptions and health seeking behaviors, oriental medical treatment and information seeking type were common health seeking behaviors of all six causal perception types. Only difference for internal causal perception types was related to hospital instructions and external causal perception types were related to dietary control. The result of this study can help health care providers, especially nurses to understand the types of causal perceptions and health seeking behaviors of Rheumatoid arthritis patients to gain treatment compliance from patients according to their causal perceptions of the illness, and use it to develop educational nursing intervention to aid health care.

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The Effect of Loading Waveform on the High Temperature Fatigue Crack Propagation in P92 and STS 316L Steel (P92와 STS 316L강의 고온 피로 균열 성장에 미치는 하중 파형의 영향)

  • 김수영;임병수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.4
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    • pp.136-140
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    • 2002
  • High temperature fatigue crack growth behavior of P92 and STS 316L steel were investigated under four load conditions using CT type specimens. Loading and unloading times for the low wave forms were combinations of 1 sec. and 50 sec., which were two symmetric wave forms and two unsymmetric wave forms. Their behaviors are characterized using ΔK parameter. In STS 316L, Crack growth rate generally increases as frequency decreases. However, sensitivity of the loading rate to crack growth rate was fecund to be far greater than that of the unloading time. It is because as loading time increases, creep occurs at crack tip causing the crack growth rate to increase. However creep does not occur at the crack tip even if the unloading time is increased. In P92 steel, crack growth rate showed same behavior as in STS 316L. But the increase in loading or unloading time made almost no difference in crack growth rate, suggesting that no significant creep occurs in P92 steel even though loading time increases. After conducting high temperature tensile tests and comparing high temperature fatigue crack growth rates under various wave forms, it was proved that P92 steel has not only good high temperature properties but also improved, better high temperature fatigue properties than STS 316L.

Corrosive Characterisics of 12Cr Alloy Steel and Fatigue Characteristics of the Artificially Degraded 12Cr Alloy Steel (고온의 인공해수 중 12Cr강의 부식피로특성에 관한 연구)

  • Jo, Seon-Yeong;Kim, Cheol-Han;Bae, Dong-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.5
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    • pp.772-778
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    • 2001
  • In this study, corrosion fatigue characteristics of 12Cr alloy steel were investigated in 3.5wt.% NaCl solution of 150$^{\circ}C$ and 4.5bar. Behavior of corrosion fatigue cracks was measured by the indirect compliance method and compared with the results in distilled water and in air. 1) 12Cr alloy steel was susceptible to temperature. Its susceptibility was increased as the temperature was increased. 2) The crack growth characteristics of 12Cr alloy steel in distilled water were similar to 3.5wt.% NaCl solution. 3) The temperature of solution affects to the crack growth characteristics of 12Cr alloy steel. In corrosion solutions of 4.5bar, 150$^{\circ}C$, fracture surfaces of corrosion fatigue crack growth at a/W=0.3 was showed the trans-granular fracture suface. As the crack grew up, it was changed to inter-granular type. In condition of high temperature, The crack growth behaviors of 12Cr alloy steel were remarkable.

An Artificial Inclusion Seeding Methodology for Fatigue Design of Aerospace Ti Castings (인공개재물 이식법을 통한 항공기용 티타늄 주물의 피로설계)

  • Paul, L. Ret;Park, Yong-Kuk;Kim, Jin-Gon
    • Journal of Korea Foundry Society
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    • v.26 no.4
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    • pp.184-190
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    • 2006
  • Presence of inclusions in Ti castings imparts detrimental effects on the mechanical performance of castings. However, actual inclusions do not occur very frequently and they are difficult to locate. As a result, acquirement of specimens for mechanical tests and thus in-depth research of the adverse influence of inclusions are challenging. To address this problem, artificial inclusion seeding methodology is developed to emulate actual inclusions in Ti investment castings. Firstly, to validate that this new methodology does not result in inherent mechanical property degradation, Ti specimens with machined, backfilled and HIPed holes are produced and compared to control (unaltered), cast Ti material. Fatigue test results indicate that this 'machine-and-HIP methodology without seeding' does not result in any fundamental mechanical property alteration, which would bias ensuing comparative results. Secondly, based on this result, validation of the artificially seeded inclusions being equivalent to 'as cast' inclusions is performed by comparing their fatigue behaviors. Test specimens created by the novel artificial inclusion seeding methodology are equivalent to Ti casting specimens containing actual cast-in inclusions, and an adverse effect of inclusions in investment castings is confirmed.

Initiation and Growth Behavior of Small Surface Fatigue Crack in SiC Reinforced Aluminum Composite (SiC 강화 알루미늄기 복합재료의 표면미소 피로균열 발생 및 진전 거동)

  • Lee, Sang-Hyoup;Choi, Young-Geun;Kim, Sang-Tae
    • Composites Research
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    • v.22 no.3
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    • pp.74-81
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    • 2009
  • Reversed plane bending fatigue tests were conducted on SiC particle reinforced and SiC whisker reinforced aluminum composite. The initiation and growth behaviors of small surface fatigue cracks were continuously monitored by the replica technique and the causes of fracture and fracture mechanism were investigated by SEM. The relationship between da/dn and $K_{max}$ show that da/dn increases in high stress level while decrease and again increases with increasing of $K_{max}$ in low stress level for two materials.

Development and Evaluation of Customized Clothing for Patients with Severe Dementia (중증 치매환자복 개발 및 사용성 평가)

  • Kwang Ae Park;Chung Eun Yang
    • Fashion & Textile Research Journal
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    • v.25 no.3
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    • pp.346-357
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    • 2023
  • The purpose of this study is to develop clothing customized for dealing with patients with severe dementia. Based on the results of previous studies, The research patient clothing was designed to reduce the physical fatigue experienced by caregivers when dressing and undressing patients by changing the position and shape of the split in the patient's clothing. This study used qualitative and quantitative methods to measure the extent to which these modifications improved the ease of dressing and undressing the research patient. The research patient clothing was developed by moving the rear-center zipper to the side and changing the zipper from being half-open to fully open. Muscle energy consumption and fatigue generation were analyzed using EMG signals at the following sites: brachioradialis, biceps, triceps, anterior deltoid, medial deltoid, posterior deltoid, upper trapezius and erector spinae. Results indicated that the modified research patient clothing required less muscle energy and the occurrence of muscle fatigue decreased overall compared to traditional patient clothing. This was supported by the qualitative subjective evaluation, which revealed that dressing and undressing was easier with the modified clothing. In conclusion, repositioning of the back zipper to the side and the fully open slit shape significantly reduced caregiver fatigue when dressing and undressing patients.

Effects of Energy Conservation Strategies on Cancer Related Fatigue and Health Promotion Lifestyle in Breast Cancer Survivors: a Randomized Control Trial

  • Sadeghi, Elham;Gozali, Nahid;Tabrizi, Fatemeh Moghaddam
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.10
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    • pp.4783-4790
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    • 2016
  • Purpose: Cancer-related fatigue is frequently experienced by patients during and after therapy. The present study was conducted to assess the impact of energy conservation strategies and health promotion in breast cancer survivors. Methods: A randomized controlled trial was carried out to compare the intervention effect (n=69.0) with controls (n=66.0) based on routine oncology ward care. The intervention was five weekly sessions for groups of 6-8 breast cancer survivors. Data on fatigue and health promotion lifestyle were obtained before and after completion the intervention and then 8 weeks later for analysis of variance (ANOVA) with repeated measures. Results: Our findings showed cancer-related fatigue to be reduced in the intervention group from pre- to post-intervention, and this persisted over the 8-weeks follow-up period (F = 69.8, p<0.001). All subscales of the cancer fatigue scale demonstrated statistically significant effects with partial eta-squared values ranging from 0.15 (the smallest effect in cognitive fatigue) to 0.21 (the largest for affective fatigue). Changes in the health promotion life style indicated a significant promotion from pre- to post-intervention, and this again continued after 8-weeks follow-up (F = 41.6, p < 0.001). All six domains of a health promoting life style featured significantly elevated values, the largest effect being seen in the interpersonal relations subscale (F=57.7, partial ${\eta}^2=0.21$, p<0.001) followed by physical activity (F=51.9, partial ${\eta}^2=0.18$, p<0.001). Conclusions: The program was effective in decreasing cancer related fatigue and promoting a healthy lifestyle.

Probabilistic Analysis of Fatigue Behavior of Induction Hardened Steel (고주파 열처리된 SAE1055 강의 피로거동 및 이의 확률론적 평가)

  • Lee, Seon-Ho;Lee, Seung-Pyo;Kang, Ki Weon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.3
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    • pp.429-436
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    • 2013
  • This study considers how the fatigue behavior and probabilistic properties of SAE1055 steel are related to its hardness level. SAE1055 steel was heat-treated using induction hardening. Five types of specimens were prepared (A: base material, B: through hardened material with HV390, C: through hardened material with HV510, D: through hardened material with HV700, and E: surface hardened material with HV700). Fatigue tests were performed under a stress ratio of R = -1 using a 4-point rotary bending fatigue tester. The fatigue behaviors were greatly influenced by the hardness, but the fatigue limit did not increase over a hardness of HV510. In addition, the effect of the hardness level on the failure mechanism was evaluated using a scanning electron microscope. The probabilistic properties of the fatigue life were investigated using a probabilistic S-N approach, and the effect of the hardness level on these properties was evaluated using a residue analysis.

Determinant factors of Exercise behaviors in Patients with Arthritis (관절염 환자의 운동행위 결정요인)

  • Suh, Gil-Hee;Lim, Nan-Young
    • Journal of muscle and joint health
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    • v.7 no.1
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    • pp.102-130
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    • 2000
  • The aims of this study were to understand and to predict the determinant factors affecting the exercise behaviors and physical fitness by testing the Ponder's health promotion model, and to help the patients with rheumatoid arthritis and osteoarthritis perform the continuous exercise program, and to help them maximize the physical effect such as muscle strength. endurance, and fuctional status and mental effects including self efficacy and quality of life, and improve the physical and mental wellbeing, and to provide a basis for the nursing intervention strategies. We analyzed the clinical records of 208 patients with rheumatoid arthritis and degenerative arthritis who visited the outpatient clinics at H university hospital in Seoul between October 5, 1999 and October 24, 1999. Data were composed of self reported questionnaire and good of fitness score which were obtained by pedalling the ergometer of bicycle for 9 minutes. SPSS Win 8.0 and Window LISREL 8.12a were used for statistical analysis. 24 Of 54 hypothetical paths were supported in modified model, which was considered as a proper model with improved fit index. The physical fitness was directly influenced by exercise participation behavior and education level, and indirectly by physical fitness, while fatigue, physical disability, pastexercise behavior, life-style, self-efficacy, which explained 20% of physical fitness. The exercise participation were directly influenced by perceived benefits and self-efficacy, and indirectly influenced by life-style, fatigue and physical disability, and directly and indirectly by past exercise behavior, which explained 53% of exercise participation. Exercise score were directly affected by perceived health status, perceived benefits, self efficacy, and past exercise behavior, and were indirectly affected by fatigue, physical disability, and life-style, which explained 50%. Perceived health status were directly influeced by level of education, depression, sleep disorder, and physical disability, which explained 34% of perceived health status. Perceived benefit was directly influenced by fatigue, sleep disorder, physical disability, and life-style, which explained 45%. Perceived barriers was directly influenced by fatigue, sleep disorder, and lifestyle, which explained 9%. Self- efficacy was directly influenced by fatigue, physical disability, past exercise behavior, and level of education, which explained 61%. In conclusion, important variables for physical fitness were exercise participation and level of education, and variables affecting exercise participation were perceived self-efficacy, benefits, and past exercise behavior. Perceived self-efficacy of exercise was a significant predictor of exercise participation. Life-style, fatigue, and physical disability showed direct effects on perceived benefit, perceived barriers, and self-efficacy, and indirect effects on exercise behavior. Therefore, disease related factor should be minimized for physical performance and well being in nursing intervention for patients with rheumatoid arthritis, and plans to promote and continue exercise should be soaked to reduce disability. In addition, Exercise program should be planned and performed by the exact evaluation of exercise according to the ability of the patients and the contents to improve the importance of exercise and self efficacy in self control program, dedicated educational program should be involved.

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Fatigue Crack Propagation Characteristics of Duplex Stainless Steel Weldments (I) (이상계 스테인리스강 용접부의 피로크랙 전파특성 (I))

  • 권종완;김상태;이택순
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.12 no.4
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    • pp.738-746
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    • 1988
  • Fatigue crack propagation of duplex stainless steel weldments was studied to develop further phenomenological understanding of the influences of welding heat cycle accompanying microstructural changes. Fatigue tests were carried out under constant amplitude of load in air at room temperature. The results showed that the crack propagation rate was different in base metal, heat affected zone and welding line. The crack propagation behavior in each part of duplex stainless steel was strongly dependent on phase ratio(.gamma../.alpha.) and several factors of microstructure also affected this propagation behavior. The fractographic feature in each part of steel were discussed on crack propagation behaviors.