• 제목/요약/키워드: stress recovery

검색결과 659건 처리시간 0.02초

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

  • 정재헌;송정일
    • 한국태양에너지학회 논문집
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    • 제28권6호
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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
    • 식품보건융합연구
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    • 제6권2호
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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.

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

  • 김위대
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2000년도 춘계학술발표대회 논문집
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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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상호목표설정 간호중재가 유방절제술 환자의 수술 후 회복에 미치는 효과 (Effect of Nursing Intervention of Mutual Goal Setting on Recovery of Mastectomy Patient)

  • 장은희
    • 기본간호학회지
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    • 제8권2호
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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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운동선수의 제5 중족골 피로골절 (Fifth Metatarsal Stress Fracture)

  • 이경태;박영욱;제갈혁;김준범
    • 대한족부족관절학회지
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    • 제16권2호
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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.

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

  • 서동우;김병철;정규산;나원기;박기태
    • 한국산학기술학회논문지
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    • 제18권12호
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    • pp.150-156
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    • 2017
  • 본 연구는 PSC(Post Tensioned Concrete) 교량 및 사장교(Cable Stayed Bridge) 등에 많이 적용되는 강연선의 국부적 손상에 따른 응력 회복길이를 분석하였다. 강연선은 PC 강선(Prestressing Strand)을 여러 줄을 꼬은 강재이며, 재료의 특성상 준공후 지속적으로 손상이 발생하며 부식 등이 주요 손상원인이다. 이에 따른 손상에 따른 성능저하가 발생하지만, 구조적인 특성상 케이블 내부의 손상 정도 및 응력 변화 패턴을 파악하기 어렵다. 교량에 적용된 케이블의 경우 설치 형상에 따라 채수 등에 따라 부식에 취약한 부분이 발생하며, 이로 인해 국부적인 손상이 발생할 수 있다. 본 연구는 교량 Post-Tensioning 또는 케이블 사장재에 주로 적용되는 강연선(7-Wire Strand)의 국부적 손상에 따른 성능저하 경향 및 응력 회복길이를 FEA 해석을 통하여 분석하였다. 향후 본 연구에서 구축하고자 하는 해석모델을 활용하여 PSC 교량 및 사장교 케이블 등의 안전성 평가 및 잔존수명 예측에 활용될 수 있을 것으로 사료된다.

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

  • 황덕상;조정훈;이창훈;장준복;김용석;이경섭;이윤재
    • 대한한방체열의학회지
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    • 제5권1호
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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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TiNi계 형상기억합금 선재의 냉간압연 및 열처리 특성 (Cold Rolling and Heat Treatment Characteristics of TiNi Based Shape Memory Wire)

  • 김록형;김희수;장우양
    • 열처리공학회지
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    • 제30권6호
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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.

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

  • 곽승현
    • Journal of Advanced Marine Engineering and Technology
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    • 제35권6호
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    • pp.809-813
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    • 2011
  • 배열회수시스템 입구덕트의 3차원 난류유동을 수치시뮬레이션 하였다. 본 연구는 덕트의 루프각을 부분적으로 수정하여 유동의 형상효과를 해석하는 것이 목표이다. 비구조 격자를 가지고 나비에 스톡스 방정식을 유한체적법으로 풀어 유체동력학적인 현상을 규명하였다. 유적선, 속도벡터, 동압, 잔차 등으로 수렴 등을 조사하였다. 난류모형은 k-epsilon, k-omega, reynolds stress 및 RNG k-epsilon 이다. 선회 및 비선회 조건을 2개의 덕트에 적용하였고 계산결과를 활용하여 최적형상설계를 검토하였다.

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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    • 제7권3호
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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.