• 제목/요약/키워드: Stress reliever

검색결과 3건 처리시간 0.014초

Failure Analysis of Stress Reliever in Heat-Transport Pipe of District Heating System

  • Cho, Jeongmin;Chae, Hobyung;Kim, Heesan;Kim, Jung-Gu;Kim, Woo Cheol;Lee, Soo Yeol
    • Corrosion Science and Technology
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    • 제21권4호
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    • pp.243-249
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    • 2022
  • The objective of the present study was to perform failure analysis of double-layered bellow (expansion joint), a core part of stress reliever, used to relieve axial stresses induced by thermal expansion of heat-transport pipes in a district heating system. The bellow underwent tensile or compressive stresses due to its structure in terms of position. A leaked position sufferred a fatigue with a tensile component for decades. A cracked bellow contained a higher fraction of martensitic phase because of manufacturing and usage histories, which induced more brittleness on the component. Inclusions in the inner layer of the bellow acted as a site of stress concentration, from which cracks initiated and then propagated along the hoop direction from the inner surface of the inner layer under fatigue loading conditions. As the crack reached critical thickness, the crack propagated to the outer surface at a higher rate, resulting in leakage of the stress reliever.

Factors Associated with Tobacco Use in Students Attending Local Government Schools in Mumbai, India

  • Chatterjee, Nilesh;Todankar, Priyamvada;Mandal, Gauri;Gupte, Himanshu;Thawal, Vaibhav;Bhutia, Tshering;Choudhuri, Leni
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권12호
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    • pp.5075-5080
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    • 2016
  • Purpose: Factors associated with ever-use and differences between ever-users and non-users of tobacco among adolescent school students from low income families in Mumbai were assessed. Materials and Methods: A self-administered questionnaire, completed by 1918 students from grades 7, 8 and 9 in 12 schools managed by the city municipal corporation in July 2015, gathered data on socio-demographic characteristics, tobacco use and tobacco-related knowledge, attitudes and beliefs. Results: Although only 1% of respondents thought tobacco was cool, nearly 35% were unaware of associations between tobacco use and health problems. Male students were almost twice as likely (OR=2.5, P <= 0.05) to have ever used tobacco compared to females and Supari (areca nut) users were eight times more likely (OR=8.99, P < 0.001) than Supari non -users. Tobacco-users were more likely to agree with statements: 'People who use tobacco have more friends' (OR=2.8, P = 0.004), 'Smoking relieves stress' (OR=5.6, P = 0.002) and 'It is possible to purchase any tobacco product within 100 yards of school' (OR=10.8, P < 0.001). Conclusion: This study highlights the gains made by tobacco prevention campaigns in that almost all students did not consider tobacco as cool or a stress reliever. However, they still need education about health consequences of tobacco-use. In addition, Supari use has to be addressed in school-based tobacco prevention and cessation initiatives. Furthermore, programs must also address perceptions and norms related to peers and tobacco use and ensure active implementation of existing laws. Such integrated measures will help ensure tobacco-free spaces around schools.

배초향 에센셜오일의 화학적 조성과 생리활성 특성 (Chemical Composition and Biological Activity of Essential Oil of Agastache rugosa (Fisch. & C. A. Mey.) O. Kuntze)

  • 홍민지;김주호;김희연;김민주;김성문
    • 한국약용작물학회지
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    • 제28권2호
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    • pp.95-110
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    • 2020
  • Background: In Korea, Agastache rugosa (Fisch. & C. A. Mey.) O. Kuntze is one of the well-known perennial plants belonging to Lamiaceae. This mint-fragranced plant has long been used for the treatment of abdominal pain, congestion, chills, and diarrhea since the Goryeo Dynasty. Although this plant has various medicinal properties, it is only used as a spice and for landscape purposes. Methods and Results: The objective of this paper was to review the chemical composition and biological properties of the essential oil of A. rugosa. Several studies reported that the essential oil contains more than 60 different chemical components of monoterpene and sesquiterpene hydrocarbons and oxygenated hydrocarbons. The major component is methyl chavicol (estragole), accounting for 64% - 88% of the oil. The chemical composition of this essential oil vaired widely according to the planting time, environmental conditions, planting distance, fertilizer application, and harvesting time. Conclusions: The essential oil of A. rugosa possesses various pharmacological properties such as antioxidant, antibacterial, anticancer, antiviral, nematicidal, antifungal, insecticidal, wrinkle improver, stress reliever, and Alzheimer's disease alleviator. Hence, the essential oil from A. rugosa could be used for the development of high value-added industrial products in the near future.