• Title/Summary/Keyword: stress recovery

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Stress Behaviors of Superheater Tubes under Load Change Operation in HRSG (배열회수보일러의 부하변동 운전에 따른 과열기 튜브들의 응력거동)

  • Chong, Chae-Hon;Song, Jung-Il
    • Journal of the Korean Solar Energy Society
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    • v.28 no.6
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    • pp.33-39
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    • 2008
  • The purpose of this study is not only to evaluate the stress behavior of tubes in superheater in HRSG during the load change operation but also to find root causes of failure from stress behavior. Firstly, temperature during operation was collected to perform stress analysis from actual HRSG. Part load and full load stress analysis which can be represented as the whole load change operations were performed using commercial finite element software. The possibility that can lead to tubes failure is found by stress analysis and its results is compared with metallurgical mircrostructure of failed tube which was taken from actual HRSG.

Acupuncture in Sport Recovery: A Brief Review

  • CHAPLEAU, Christopher
    • The Korean Journal of Food & Health Convergence
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    • v.6 no.2
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    • pp.23-26
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    • 2020
  • Active and therapeutic sport recovery is becoming a popular and important component in approving performance for pro and recreational athletes alike. It is also helping in the realm of injury prevention. In the search of finding modalities that are widely effective, natural, and safe, acupuncture is a viable and cost-effective treatment for helping athletes achieve this goal. More direct related research is needed, but testimonials from pro athletes and the body of research that currently exists provides powerful evidence on acupunctures ability to help with enhancing recovery. Specializing in acupuncture and exercise science, Chris integrates acupuncture into musculoskeletal rehabilitation therapy or fitness training for pain modulation, speedy recovery, and enhanced performance. Clients can choose to focus on one-on-one corrective exercise therapy, manual and massage therapy, or acupuncture. However, for best results, Chris recommends all three. Other modalities that he uses in therapy are acu-taping, herbal therapy, nutrition supplementation, cupping, guasha, and stretching techniques. The corrective exercise component is one-on-one body balancing management, focusing on strength and conditioning, post physical rehab - exercise therapy, integrative sport specific exercise, weight loss, core strengthening, dynamic lumbar stabilization, active recovery techniques, and myo-fascial release techniques. The acupuncture component focuses on sport injuries, myofascial pain, peripheral neuropathy, arthritis, facial rejuvenation, stress, smoking cessation, addiction detoxification program, weight management, sport recovery and performance.

Modeling the Relaxation Behavior of a Polymeric Composite (열가소성 복합재료의 응력완화 모델링)

  • 김위대
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.04a
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    • pp.76-79
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    • 2000
  • Polymeric composites exhibit highly nonlinear and rate dependent behavior during loading and unloading in off-axis directions. The equilibrium state of stress during loading is lower than the state of stress produced at finite strain rates. The amount of stress relaxation during loading decreases. Interestingly, however, the stress goes up to reach to the equilibrium state of stress for a fixed displacement during unloading. The unloading behavior is quite similar to the loading behavior. The stress relaxation patterns during loading and unloading is also similar, and those depend on the fiber orientation angles and the loading and unloading rates. The AS4/PEEK thermoplastic composite is used to characterize the relaxation behavior for different off-axis angles and loading rates. There exists a transient loading region at the beginning of unloading. The effective stress and effective plastic strain concept is used to establish a master curve of stress recovery pattern for different off-axis angles and unloading rates.

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Effect of Nursing Intervention of Mutual Goal Setting on Recovery of Mastectomy Patient (상호목표설정 간호중재가 유방절제술 환자의 수술 후 회복에 미치는 효과)

  • Jang Eun-Hee
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.8 no.2
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    • pp.172-188
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    • 2001
  • Purpose: The purpose of this research was to test the effectiveness of the nursing intervention, mutual goal setting, for patients who have had a mastectomy. Special reference was given to King's goal attainment theory and a theoretical framework for establishing an effective nursing strategy to enhance patient recovery is suggested. Method: This research employed a quasi-experimental design which consisted of pretest-posttest non-equivalent control and experimental groups. Data were collected from 37 patients who had a mastectomy and were hospitalized in the Department of Surgery of Y Medical Center from January 2001 to May 2001. The experimental group received the nursing intervention, mutual goal setting four times from the day before the operation to the fifth day after the operation while the control group received only routine nursing care. As postoperative recovery indicators, ROM of arm joints, arm circumference, pain, physical symptoms, oxygen saturation stress, anxiety and body image were measured. Result: The test results are as follows : 1) there were statistically significant differences between the experimental and control groups in extension and internal rotation of the shoulder Joint and flexion of the wrist joint. 2) there was no significant difference between the two groups in arm circumference. 3) there were no significant differences between the two groups in pain, physical symptoms, or oxygen saturation. 4) there were no significant differences between the two groups in stress, anxiety, or body Image. On the basis of research results, the following are recommended : 1) The effectiveness of nursing intervention in the acute recovery period as well as long term effects need to be investigated. 2) There is a need to develop an instrument to measure perception which facilitates goal attainment in the interactive setting between patients and nurses.

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Fifth Metatarsal Stress Fracture (운동선수의 제5 중족골 피로골절)

  • Lee, Kyung-Tai;Park, Young-Uk;JeGal, Hyuk;Kim, Jun-Beom
    • Journal of Korean Foot and Ankle Society
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    • v.16 no.2
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    • pp.87-93
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    • 2012
  • Fractures located at the metaphyseal/diaphyseal junction at the base of the fifth metatarsal were first described by Sir Robert Jones in 1902. However, ever since, there has been disagreement and debate regarding the diagnosis, classification, pathomechanics, the incidences, and potential causes of delayed unions and nonunions, and the optimal method of treatment. It appears to be widely agreed that proximal fractures of the metaphyseal/diaphyseal region of the fifth metatarsal are prone to delayed union or even nonunion. Several classifications of proximal fifth metatarsal stress fractures have been devised. Torg et al. classified fractures involving the proximal part of the diaphysis of the fifth metatarsal into three types. The Torg classification is a good grading system that can be used to determine the type of surgery needed as well as for the prediction of prognosis. The ''plantar gap'' might add to the decision-making process for surgery and improve the prediction of patient prognosis. In addition, the new classification using 'plantar gap' might be used for classification of fifth metatarsal stress fracture. Fifth metatarsal stress fractures can be treated conservatively or surgically, and excellent results have been reported for surgery with rapid recovery in athletes. Intramedullary screw fixation has become a popular form of fixation for fifth metatarsal stress fractures. Bone grafting presents the problems of a longer recovery time and additional skin incision for harvesting. The modified tension band wiring is an useful and simple option for surgical treatment of challenging fifth metatarsal stress fractures.

Study on Stress Recovery Length of 7-Wire Strand due to Local Damage (강연선의 국부적 손상에 따른 응력 회복길이 분석 연구)

  • Seo, Dong-Woo;Kim, Byung-Chul;Jung, Kyu-San;Na, Wongi;Park, Ki-Tae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.12
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    • pp.150-156
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    • 2017
  • This study examined the stress recovery length due to the local damage of a 7-wire strand, which is applied widely to PSC (Post Tensioned Concrete) bridges and cable-stayed bridges. The 7-wire strand is a multiple stranded steel of PC prestressing strand. Owing to the nature of the material, it is damaged continuously after completion with corrosion being the main cause of damage. On the other hand, due to its structural characteristics, it is difficult to grasp the degree of damage inside the cable and the pattern of stress variation. In the case of cables applied to bridges, the parts that are susceptible to corrosion are generated depending on the water supply and installation shape, which may cause local damage. This study analyzed the tendency of performance degradation and stress recovery length according to local damage of a 7-wire strand, which is applied mainly to bridge post-tensioning or stay cables. This study developed a computer-based simulation model that was validated with experimental results. The model developed in this study can be used to evaluate the safety level and estimate the remaining life span of P SC bridges or cable-stayed bridges.

Effects of Acupuncture on patients with cold hypersensitivity by Cold Stress Test : pilot study (냉부하검사(CST)를 활용한 수부냉증의 침치료 효과에 대한 예비 연구)

  • Hwang, Deok-Sang;Cho, Jung-Hoon;Lee, Chang-Hoon;Jang, Jun-Bock;Kim, Yong-Seok;Lee, Kyung-Sub;Lee, Yoon-Jae
    • Journal of Oriental Medical Thermology
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    • v.5 no.1
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    • pp.69-77
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    • 2006
  • Purpose : There are many patients with cold hypersensitivity who want oriental medicine treatment. But there has been no study of acupucture treatment effect on patients. So we examined effects of acupuncture treatment at different acupuncture points and compared results of 1st cold stress test and 2nd cold stress test. Method : 8 patients with hand cold hypersensitivity applied for this study. To rule out an bias, we excluded the patients with skin diseases, spinal nerve disease of cervial spine, external wounds. We measured body temperature with D.I.T.I. We performed cold stress test(CST) by 6 thermographic observation using D.I.T.I ; the 1st was taken after 15 minutes-resting, the 2nd was immediately taken after 1 minute soak in $20^{\circ}C$ water, the 3rd was taken at 10 minutes after the soak, and after a week, the 4th was taken after 15 minutes resting, the 5th was immediately taken after 1 minute soak in $20^{\circ}C$ water, the 6th was taken after 10 minutes with acupunture treatment. There were two groups of patients. First group was acupuncture that performed acupuncture therapy on distal points. Second group was acupuncture that performed acupuncture therapy on proximal points. We compared first CST and second CST recovery rate result. Results : The recovery rate at distal points acupuncture therapy was higher than before of that. but not significantly different. The recovery rate at proximal points acupuncture therapy was significantly higher than before of that. The recovery rate of both the back, the palms, all fingers of after proximal acupuncture therapy was significantly higher than before of that. Conclusions : Acupuncture could be effective therapy method on cold hypersensitivity, especially using proximal acupuncture points could be good at cold hypersensitivity patients. This was pilot study of very small samples, results had limitations. For further results more examine would be needed.

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Cold Rolling and Heat Treatment Characteristics of TiNi Based Shape Memory Wire (TiNi계 형상기억합금 선재의 냉간압연 및 열처리 특성)

  • Kim, R.H.;Kim, H.S.;Jang, W.Y.
    • Journal of the Korean Society for Heat Treatment
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    • v.30 no.6
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    • pp.251-257
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    • 2017
  • The effect of annealing temperature on the martensitic transformation behavior, tensile deformation chracteristics and shape recovery etc., has been studied in TiNi based shape memory ribbon fabricated by coldrolling of wire. TiNi based shape memory wire (${\phi}=500{\mu}m$) of which structure is intermetallic compound could be cold-rolled without process annealing up to the reduction rate in thickness of 50%, but a few cracks appear in cold-rolled ribbon in the reduction rate in thickness of 65%. The $B2{\rightarrow}R{\rightarrow}B19^{\prime}$ martensitic transformation or $B2{\rightarrow}B19^{\prime}$ martensitic transformation occurs in annealing conditions dissipating lattice defects introduced by coldrolling. However, in case of higher reduction rate or lower annealing temperature, martensitic transformation in cold-rolled and then annealed ribbons does not occur. The maximum shape recovery rate of cold-rolled ribbons with the reduction rate of 35 and 65% could be achieved at annealing temperatures of 250 and $350^{\circ}C$, respectively. The shape recovery rate seems to be related to the stress level of plateau region on stress-strain curve.

Numerical Simulation of Turbulent Flows in Inlet Duct of Heat Recovery Steam Generator (배열회수 안내덕트 내부의 난류유동 수치시뮬레이션)

  • Kwag, Seung-Hyun
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.6
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    • pp.809-813
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    • 2011
  • Turbulent flows are numerically simulated in the three dimensional inlet duct for heat recovery steam generator. The present study is aimed to analyze the effect of a variation in turbulent flow pattern by the change of roof angle in the transition duct. The finite volume based Navier-Stokes equations with unstructured grids are solved to make clear the flow dynamic phenomena. Reviews are made on with the data of path lines, velocity vectors, dynamic pressure, residuals for numerical convergence and so on. The k-epsilon, k-omega, Reynolds stress and RNG k-epsilon are used for generation of turbulence. Two types of roof angle are applied with and without the swirl in the duct. Turbulent flow patterns could be investigated for the optimum duct design based on the computational results.

Comparative Drought Resistances among Eleven Warm-Season Turfgrasses and Associated Plant Parameters

  • Kim, Ki Sun;Beard, James B.
    • Weed & Turfgrass Science
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    • v.7 no.3
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    • pp.239-245
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    • 2018
  • Comparative drought resistances of 11 perennial warm-season turfgrasses were evaluated in the field after withholding irrigation for 48 days in summer I and 57 days in summer II. There were significant variations among the grasses in their drought resistances. From two years study of field shoot recovery from drought stress, the relative rankings among the 11 warm-season turfgrasses was as follows. 'Arizona Common' and 'Texturf 10' bermudagrasses [Cynodon dactylon (L.) Pers.], 'Tifgreen' hybrid bermudagrass [C. dactylon (L.) Pers. ${\times}$ C. transvaalensis Davy], and 'Georgia Common' centipedegrass [Eremochloa ophiuroides (Munro.) Mack.] possessed good drought resistances, whereas 'Texas Common' St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] and 'Tifway' hybrid bermudagrass [Cyndon dactylon (L.) Pers ${\times}$ C. transvaalensis Davy] possessed poor drought resistances. 'Texas Common' buffalograss [Buchloe dactyloides (Nutt.) Engelm.], 'Pensacola' bahiagrass (Paspalum notatum Flugge.), and 'Adalayd' seashore paspalum (Paspalum vaginatum Swartz), 'Meyer' zoysiagrass (Zoysia japonica Steud.), 'Emerald' zoysiagrass (Z. japonica Steud. ${\times}$ Z. tenuifolia Willd. ex Trin.) were found to rank intermediate. Visual leaf firing showed the highest correlation (r=-0.84) to shoot recovery from drought stress. Visual leaf rolling (r=-0.59) and canopy-air temperature differential (r=-0.64) also showed very significant correlations, whereas leaf water potential (r=0.54) showed relatively lower correlation.