• 제목/요약/키워드: stress recovery

검색결과 659건 처리시간 0.034초

적응적 p-Version 유한요소법에서 정규 크리깅에 의한 응력복구기법 (Stress Recovery Technique by Ordinary Kriging Interpolation in p-Adaptive Finite Element Method)

  • 우광성;조준형;이동진
    • 대한토목학회논문집
    • /
    • 제26권4A호
    • /
    • pp.677-687
    • /
    • 2006
  • 크리깅 보간법은 지구통계학 분야에 주로 사용되는 보간법의 하나이다. 이 방법은 실험적 베리오그램과 이론적 베리오그램의 작성과 크리깅 보간법의 정식화에 관한 연구를 포함하고 있다. 종래의 응력복구를 위한 최소제곱법과 대조적으로, 가우스적분점에서의 응력데이타로부터 준정해를 얻기 위해 가중 최소제곱법에 기초를 둔다. 즉, 동일한 가중치를 사용하는 종래의 방식들과는 달리 가우스적분점에서의 응력값의 보간을 위하여 베리오그램 모델링을 통한 가중치가 결정된다. 한편, 분할된 요소망에 Zienkiewicz와 Zhu에 의해 제안된 SPR기법에 기초를 둔 사후오차평가를 통해 p-차수를 균등 또는 선택적으로 증가시키는 자동체눈 방식이 도입되었다. 이 방법의 정당성을 보기위해 인장력을 받는 개구부를 갖는 평판문제를 해석하였다. 또한, 기존의 최소제곱법과의 비교를 통한 크리깅보간법의 정당성을 보여 주었다.

중간가공열처리한 AI-Li계 합금의 고온변형거동 (The Hot Deformation Behaviors of Intermediate Thermo-Mechanical Treated Al-Li Based Alloy)

  • 유창영;진영철
    • 열처리공학회지
    • /
    • 제4권3호
    • /
    • pp.1-6
    • /
    • 1991
  • In this study, intermediate thermo-mechanical treated Al-2.0 wt%Li, and Al-2.0 wt%Li-1.2 wt%Cu-1.0 wt%Mg-0.12 wt%Zr alloys were tested in tension at $10^{\circ}C$ and elevated temperature(100, 200 and $300^{\circ}C$). The results are follows : The tensile strength of Al-Li-Cu-Mg-Zr alloy is the highest but the elongation of Al-Li alloy is the highest(106%) among the all alloys in tension at $300^{\circ}C$. The Portervin-LeChartlier effect is showed in AI-Li-Cu-Mg-Zr alloy at 10 and $100^{\circ}C$, because of tangled dislocation by Mg and Cu. In the true stress-strain curves of all alloy, the peaks of stress at $300^{\circ}C$ are showed at the strain less than 0.1. In the binary alloy, the dynamic restoration process at 200 and $300^{\circ}C$ is nearly similar to dynamic recovery type. The hot deformation stress is decreased with increase of dynamic recovery degree, but the elongation is increased. When the strain the strain rate are constant, the temperature dependence of hot deformation stress is increased with increase of deformation temperature. The elongation and degree of dynamic recovery are decreased with increase of hot deformation activation energy, but the deformation stresses slightly increased.

  • PDF

Coping Mechanisms Utilized by Individuals With Drug Addiction in Overcoming Challenges During the Recovery Process: A Qualitative Meta-synthesis

  • Agus Setiawan;Junaiti Sahar;Budi Santoso;Muchtaruddin Mansyur;Syamikar Baridwan Syamsir
    • Journal of Preventive Medicine and Public Health
    • /
    • 제57권3호
    • /
    • pp.197-211
    • /
    • 2024
  • Objectives: Recovery from drug addiction often poses challenges for the recovering person. The coping mechanisms employed by these individuals to resist temptations and manage stress play a key role in the healing process. This study was conducted to explore the coping strategies or techniques that individuals with addiction use to handle stress and temptation while undergoing treatment. Methods: A qualitative meta-synthesis approach was utilized to critically evaluate relevant qualitative research. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines were used for article selection, with these standards applied to 4 academic databases: Scopus, PubMed, ProQuest, and CINAHL. The present review included studies published between 2014 and 2023, selected based on pre-established inclusion criteria. The quality of the studies was assessed using the Critical Appraisal Skills Programme Qualitative Studies Checklist. This review was registered with the International Prospective Register of Systematic Reviews (PROSPERO) under the registration number CRD42024497789. Results: The analysis of 13 qualifying qualitative articles revealed 5 major themes illustrating the coping mechanisms employed in the pursuit of recovery by individuals who use drugs. These themes include seeking social support, as well as psychological coping strategies, spiritual experiences, professional interventions, and the enhancement of awareness. Conclusions: Among individuals with drug addiction, coping mechanisms are crucial for resisting stress and temptations throughout the recovery process. Healthcare professionals, as medical specialists, can establish more thorough and effective plans to support these patients on their path to recovery.

정신적 스트레스가 경항부 근육에 미치는 영향 (The Effects of Psychological Stress on Neck Muscles)

  • 권호영;김정환
    • 한방재활의학과학회지
    • /
    • 제20권1호
    • /
    • pp.119-132
    • /
    • 2010
  • Objectives : The purpose of this study is to compare interrelations between stress and muscles of neck through stress response inventory(SRI), 7 zone diagnostic system and surface electromyography(sEMG). Methods : This study was carried out with the data from SRI, 7 zone diagnostic system and sEMG. First subjects were divided into two group according to the SRI points. subjects in group A had points of SRI in which lower than 30 points. Subjects in group B had points of SRI in which higher than 30 points. And subjects were divided into nonstress group(Group C) and stress grouop(Group D) according to the result of 7 zone diagnostic system. Then we investigated how to differentiate the muscle contraction, fatigue, recovery and asymmetry ratio on sEMG for each groups. Results : In this study, the muscle contraction of both upper trapezius muscle and left sternocleidomastoid muscle and left scalene muscle in stress group were higher than nonstress group significantly. And the muscle recovery of left sternocleidomastoid muscle and left scalene muscle in stress group were higher than nonstress group significantly. Conclusions : This results show that the stress was associated with muscle condition.

배열회수보일러 기수분리기의 응력해석 및 평가 (Stress Analysis and Evaluation of Steam Separator of Heat Recovery Steam Generator (HRSG))

  • 이부윤
    • 한국기계가공학회지
    • /
    • 제17권4호
    • /
    • pp.23-31
    • /
    • 2018
  • Stress of a steam separator, equipment of the high-pressure (HP) evaporator for a HRSG, was analyzed and evaluated according to ASME Boiler & Pressure Vessel Code Section VIII Division 2. First, from the analysis results of the piping system model of the HP evaporator, reaction forces of the riser tubes connected to the steam separator, i.e., nozzle loads, were derived. Next, a finite element model of the steam separator was constructed and analyzed for the design pressure and the nozzle loads. The results show that the maximum stress occurred at the bore of the riser nozzle. The primary membrane stresses at the shell and nozzle were found to be less than the allowable stress. Next, the steam separator was analyzed for the steady-state operating conditions of operating pressure, operating temperature, and nozzle loads. The maximum stress occurred at the bore of the riser nozzle. The primary plus secondary membrane plus bending stress at the shell and nozzle was found to be less than the allowable stress.

Big Data Decision Analysis of Stress on Adolescent Mental Health

  • Park, Jinhyeok;Kang, Un Gu;Lee, Youngho
    • 한국컴퓨터정보학회논문지
    • /
    • 제22권11호
    • /
    • pp.89-96
    • /
    • 2017
  • This study analyzed how mental health affects stress in adolescents. The subjects of the study were data of about 60,000 middle and high school students living in the country, using cross-tabulation data and chi - square test to analyze the relationship between stress and mental health of adolescents. As a result of the research, it was found that the adolescents exposed to the excessive stress showed a poor correlation with the recovery of the fatigue, while the adolescents with relatively low stress showed the good recovery of fatigue. In the case of mental illness, depression or despair, the students who answered that they were stressed showed a lot of experience. In the case of suicide ideation, suicide attempt, and suicide attempt, the number of attempts to commit suicide was high when the level of perceived stress was high similar to the result of previous analysis. This finding confirms that stress is an important factor in the quality of life in adolescent mental health. It can be used as a strategy and business to prevent the problem of youth suicide in modern society in advance by stress management.

Al-Mg 합금의 고온 소성 변형 특성에 미치는 동적 변형 시효의 영향 (The Effect of Dynamic Strain Aging on the High Temperature Plastic Deformation Behaviour of Al-Mg Alloy)

  • 이상용;이정환
    • 소성∙가공
    • /
    • 제5권4호
    • /
    • pp.327-336
    • /
    • 1996
  • The effect of dynamic strain aging on high temperature deformation behaviour of the A-Mg alloy was investigated by strain rate change tests and stress relaxation tests between 20$0^{\circ}C$and 50$0^{\circ}C$. Yield point, short stress transient and periodic discontinuities on the stress-strain curve were considered as an evidence of the effect of dynamic strain aging. With this criterion two distinct strain rate-temperature regimes could be manifested. Dynamic strain aging was considered to be effective in the high temperature-low strain rate regime, whereas dynamic recovery was a dominant deformation mechanism in the low temperature-high strain rate regime. It was found that dynamic strain aging in the high temperature deformation was governed by the mechcanism of diffusion-controlled, viscous dislocation movement.

  • PDF

AA5083 합금의 고온유동응력 및 연신율에 미치는 압연온도와 패스변형량의 영향 (The Effects of Pass Strain and Rolling Temperature on Flow Stress and Flow Strain of AA5083 Alloy)

  • 고병철;박도현;유연철
    • 소성∙가공
    • /
    • 제8권2호
    • /
    • pp.169-177
    • /
    • 1999
  • Different pass strains and rolling temperatures were applied to understand the effects of pass strain and rolling temperature on flow stress and flow strain of AA5083 alloy. The specimens were prepared by conventional casting process followed by hot rolling. Hot torsion tests were conducted at temperature ranges of 350 to 52$0^{\circ}C$ under a strain rate of 1.0/sec. During the process, hot-restoration mechanisms, dynamic recovery(DRV) or dynamic recrystallization (DRX), of the AA5083 alloy were analyzed from the flow curves and deformed microstructures. It was found that while the rolling strain per pass and rolling temperature have little effect on the folw stress, they have significant effect on the failure strain. The DRV was responsible for the hot restoration mechanism of the hot-rolled specimen. heavily elongated grains and small subgrains containing dislocations were obtaned during the hot deformation. This was due to the presence of Al6Mn precipitate in the alloy.

  • PDF

의료기관 진료비 삭감율 및 이의신청 회수율과 관련되는 관리요인 (The Management Factors of Medical Expenditure Reduction and Recovery of Hospital Health Insurance Department)

  • 박현숙
    • 한국병원경영학회지
    • /
    • 제13권4호
    • /
    • pp.46-75
    • /
    • 2008
  • Main objective of this study is to investigate the factors that affect the reduction and recovery rate of hospital health insurance review departments of Korean tertiary hospitals, general hospitals and hospitals. A nationwide mail survey was conducted through structured questionnaire for chiefs and members of health insurance review departments of 178 hospitals, and data from 1,064 respondents were utilized in the final analysis. Major findings are as follows: 1) Monthly average reduction rate of surveyed hospitals was 1.18% for inpatients and 0.56% for outpatients. Also, average recovery rates from protests were 45.7% and 53.6%, respectively. 2) Average ages of health insurance review department employees were 41.5 for chiefs and 34.9 for members, and their average working period was 6.64 years. 69.1% of the respondents felt stress in their jobs, and they suggested 'communication problems with doctors' along with 'heavy workloads' as major reasons for the stress. 3) Reduction rates decreased and recovery rates increased when separate member in charge was assigned to each medical department, when health insurance review departments periodically provided medical parts with related education, and when the members participated in various committees.

  • PDF

Transcript Analysis of Wheat WAS-2 Gene Family under High Temperature Stress during Ripening Period

  • Ko, Chan Seop;Kim, Jin-Baek;Hong, Min Jeong;Kim, Kyeong Hoon;Seo, Yong Weon
    • Plant Breeding and Biotechnology
    • /
    • 제6권4호
    • /
    • pp.363-380
    • /
    • 2018
  • Wheat is frequently exposed to high temperature during anthesis and ripening period, which resulted in yield loss and detrimental end-use-quality. The transcriptome analysis of wheat under high temperature stress during the early stage of the grain filling period was undertaken. Three expression patterns of differentially expressed genes (DEGs) during grain filling period were identified. The DEGs of seed storage protein and starch-branching enzyme showed continuous increases in their expressions during high temperature stress, as well as during the recovery period. The activities of the enzymes responsible for the elimination of antioxidants were significantly affected by exposure to high temperature stress. Only the WAS-2 family genes showed increased transcription levels under high temperature stress in dehulled spikelets. The relative transcription levels for sub-genome specific WAS-2 genes suggested that WAS-2 genes reacted with over-expression under high temperature stress and decreased back to normal expression during recovery. We propose the role of WAS-2 as a protective mechanism during the stage of grain development under high temperature in spikelets.