• Title/Summary/Keyword: Stress index

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Stress Index Development for Piping with Trunnion Attachment Under Pressure and Moment Loadings

  • Lee, Dae-hee;Kim, Jong-Min;Park, Sung-ho
    • Nuclear Engineering and Technology
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    • v.29 no.4
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    • pp.310-319
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    • 1997
  • A finite element analysis of a trunnion pipe anchor is presented. The structure is analyzed for the case of internal pressure and moment loadings. The stress results are categorized into the average (membrane) stress, the linearly varying (bending) stress and the peak stress through the thickness. The resulting stresses are interpreted per Section III of the ASME Boiler and Pressure Vessel Code from which the Primary(B$_1$), Secondary(C$_1$) and Peak(K$_1$) stress indices for pressure, the Primary (B$_2$), Secondary(C$_2$) and Peak(K$_2$) stress indices for moment are developed. Based on the comparison between stress value by stress indices derived in this paper and stress value represented by the ASME Code Case N-391-1, the empirical equations for stress indices are effectively used in the piping stress analysis. Therefore, the use of empirical equations can simplify the procedure of evaluating the local stress in the piping design stage.

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Comparative Analysis of the 2022 Southern Agricultural Drought Using Evapotranspiration-Based ESI and EDDI (증발산 기반 ESI와 EDDI를 활용한 2022년 남부지역의 농업 가뭄 분석)

  • Park, Gwang-Su;Nam, Won-Ho;Lee, Hee-Jin;Sur, Chanyang;Ha, Tae-Hyun;Jo, Young-Jun
    • Journal of The Korean Society of Agricultural Engineers
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    • v.66 no.3
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    • pp.25-37
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    • 2024
  • Global warming-induced drought inflicts significant socio-economic and environmental damage. In Korea, the persistent drought in the southern region since 2022 has severely affected water supplies, agriculture, forests, and ecosystems due to uneven precipitation distribution. To effectively prepare for and mitigate such impacts, it is imperative to develop proactive measures supported by early monitoring systems. In this study, we analyzed the spatiotemporal changes of multiple evapotranspiration-based drought indices, focusing on the flash drought event in the southern region in 2022. The indices included the Evaporative Demand Drought Index (EDDI), Standardized Precipitation Evapotranspiration Index (SPEI) considering precipitation and temperature, and the Evaporative Stress Index (ESI) based on satellite images. The Standardized Precipitation Index (SPI) and SPEI indices utilized temperature and precipitation data from meteorological observation stations, while the ESI index was based on satellite image data provided by the MODIS sensor on the Terra satellite. Additionally, we utilized the Evaporative Demand Drought Index (EDDI) provided by the North Oceanic and Atmospheric Administration (NOAA) as a supplementary index to ESI, enabling us to perform more effective drought monitoring. We compared the degree and extent of drought in the southern region through four drought indices, and analyzed the causes and effects of drought from various perspectives. Findings indicate that the ESI is more sensitive in detecting the timing and scope of drought, aligning closely with observed drought trends.

Characterization of the brittleness of hard rock at different temperatures using uniaxial compression tests

  • Chen, Guoqing;Li, Tianbin;Wang, Wei;Guo, Fan;Yin, Hongyu
    • Geomechanics and Engineering
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    • v.13 no.1
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    • pp.63-77
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    • 2017
  • The failure mechanism of a deep hard rock tunnel under high geostress and high geothermalactivity is extremely complex. Uniaxial compression tests of granite at different temperatures were conducted. The complete stress-strain curves, mechanical parameters and macroscopic failure types of the rock were analyzed in detail. The brittleness index, which represents the possibility of a severe brittleness hazard, is proposed in this paperby comparing the peak stress and the expansion stress. The results show that the temperature range from 20 to $60^{\circ}C$ is able to aggravate the brittle failure of hard rock based on the brittleness index. The closure of internal micro cracks by thermal stress can improve the strength of hard rock and the storage capacity of elastic strain energy. The failure mode ofthe samples changes from shear failure to tensile failure as the temperature increases. In conclusion, the brittle failure mechanism of hard rock under the action of thermal coupling is revealed, and the analysis result offers significant guidance for deep buried tunnels at high temperatures and under high geostress.

Development of a "Grandmothering Stress Index" for Korean Day-care Grandmothers (손자녀 양육 스트레스 측정도구 개발 - 주간양육 할머니를 중심으로 -)

  • Kim, Moon-Jeong;Chung, Chae-Weon
    • Women's Health Nursing
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    • v.14 no.1
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    • pp.56-65
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    • 2008
  • Purpose: The study was to develop an instrument to measure grandmothering stress for Korean day-care grandmothers and to test the validity and reliability of the instrument Method: The items of the instrument were based on a literature review and secondary data, After content validity tests and a pilot test, 20 items were developed. In order to test the reliability and validity of the scale, data were collected from 126 grandmothers. Result: After a factor analysis, five factors and 15 items were selected. These explained 67.2% of the total variance. The first domain was termed 'Health problems', and explained 18.1 % of the total variance, and the second domain of 'Possibility of role substitution' explained 13.8%. The third and the fourth domains were 'Relations with adult children' and 'Grandchildren's characteristics' explaining 12.5% and 12.1 %, respectively. The last domain explained 10.8% of the total variance with the theme 'Restriction of social life' After accomplishing the reliability analysis, Cronbach's alpha coefficient was determined to be .75. Conclusions : This initial step in the development of a Grandmothering Stress Index is valuable to reflect the subject of Grandmothering stress in senior citizens in Korea. Future study should to refine the constitution of the instrument.

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Effects of Furlough Caused by External Factors on the Pilot's Stress Index (외부요인으로 인한 업무 공백이 조종사의 스트레스 수준에 미치는 영향)

  • Cho, Yul hyun;Kwon, Moonjin;Song, Byung Heum
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.29 no.2
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    • pp.47-54
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    • 2021
  • Recently, the issue of maintaining pilot competency has emerged as one of the major challenges in the aviation industry due to irregular schedules and flight intervals caused by the global COVID-19. Therefore, a survey was conducted on airline pilots to determine how stressed they would be when returning to their flights after experiencing irregular schedules or long-term furloughs. The level of stress that pilots receive due to flight intervals was divided into periods, and correlation with general characteristics was identified to see what emotional burdens exist as the lengths of flight interval increased. As a result, burdened flight intervals and the Pilot Flying(PF) intervals were identified as a statistically significant variables. In the case of the Pilot Flying interval, the level of stress was confirmed to be worse as the flying interval was elongated, and in the case of the burdened flying interval, the tendency of the stress index were lower as the period increased. Through this study, pilots who experienced reduced flight times were found to be accompanied by considerable amount of emotional burden proportionate to the length of the interval period.

Physiological and Genetic Responses of Salt-stressed Tunisian Durum (Triticum turgidum ssp. durum) Cultivars

  • Kim, Sang Heon;Kim, Dae Yeon;Yacoubi, Ines;Seo, Yong Weon
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.63 no.4
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    • pp.314-321
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    • 2018
  • Durum (Triticum turgidum L. ssp. durum) is a major crop species cultivated for human consumption worldwide. In Tunisia, salt stress is one of the main problems that limit crop production. 'Mahmoudi' was selected as the most salt-sensitive out of 11 Tunisian durum cultivars. Using the salt-tolerant cultivar 'Om Rabia', resistant and susceptible cultivars were evaluated to compare genetic responses under salt stress. At the fully expanded third leaf stage, salt stress was applied by submerging the pots in 500 mM NaCl for 5 min every day for saline water irrigation in the greenhouse. The treatment was applied for 1 week and salt stress tolerance was determined by changes of growth parameters to the control condition. The salt tolerance trait index and salt tolerance index were calculated and used as selection criteria. The expression levels of TdHKT1;4, TdHKT1;5, and TdSOS1 were examined using qPCR. For further evaluation of physiological responses, salt stress (150 mM NaCl) was additionally applied for 48 h at the fully expanded third-leaf stage. Increased expression of the genes responsible for salt tolerance and proline content in tolerant durum can be used to broaden genetic diversity and provide genetic resources for the durum breeding program.

Acute Stress Disorder Patients Treated with Yanshimtang-Gamibang: Three Case Reports (급성 스트레스 장애에 대한 양심탕가미방(養心湯加味方) 치험 3례)

  • Lim, Su-Yeon;Moon, Young-Joo;Lee, Ji-Yun;Jeon, Hyun-A;Koh, Young-Tak
    • Journal of Oriental Neuropsychiatry
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    • v.30 no.3
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    • pp.295-304
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    • 2019
  • Objectives: The purpose of this case report was to propose Yangshimtang-Gamibang on three patients diagnosed with acute stress disorder. Methods: Yangshimtang-Gamibang was treated on three patients diagnosed with acute stress disorder after experiencing a traffic accident. The effects of Yangshimtang-Gamibang were evaluated through BAI (Beck Anxiety Inventory), NRS (Numerical rating scale), NDI (Neck Disability Index), ODI (Oswestry Disability Index), respectively, and quality of sleep was assessed with total sleep time and number of times waking up during sleep. Results: After the treatment, there was significant decrease in the value of BAI score, a measurement of anxiety, as well as the value of NRS, NDI, ODI, a measure of pain. Also, the sleep quality of three patients improved. Conclusions: The results indicate that Yangshimtang-Gamibang may have an effect on people with acute stress disorder who recently experienced a traffic accident.

Change of Refractive Index and Residual Stresses of Ta2O5 Thin Film Prepared by Dual Ion Beam Sputtering Deposition as the Substrate Temperature and Assist ion Beam Energy (이중 이온빔으로 제작한 Ta2O5 박막의 기판 온도 및 보조 이온빔 에너지에 따른 굴절률과 판류응력의 변화)

  • Yeon, Seok-Gyu;Kim, Yong-Tak;Kim, Hwek-Yung;Kim, Myoung-Jin;Lee, Hyung-Man;Yoon, Dae-Ho
    • Journal of the Korean Ceramic Society
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    • v.42 no.1
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    • pp.28-32
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    • 2005
  • The optical properties and intrinsic stress of $Ta_{2}O_{5}$ thin films deposited by Dual ion-Beam Sputtering: (DIBS) and Single ion-Beam Sputtering (SIBS) were studied as a function of the substrate temperature and assist ion beam voltage. The refractive index showed the maximum value (n = 2.144) at $150^{circ}C$ in the SIBS process. When the substrate temperature has above $150^{circ}C$ in the SIBS process the refractive index decreased. In the DIBS process, the increase of the substrate temperature affected the increase of the refractive index at a maximum value (n = 2.1117, at $200^{circ}C$). The low temperature process $(<100^{circ}C)$ can greatly reduce residual stress with the assist ion gun, but the high temperature process was unaffected. As the assist ion beam voltage increase from 250 to 350 V the refractive index increased to 2.185. However, the refractive index was decreased at the range of 350-650 V, As the assist ion beam voltage increased, the stress of the deposited film decreased to 0.1834 GPa at 650 V.

The Characteristics of Bioclimatic Types According to Annual Cumulative Temperature-Humidity Index in South Korea (남한의 연 누적 온습도 지수에 따른 생리기후유형의 특성)

  • Kang, Chul-Sung
    • Journal of the Korean Geographical Society
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    • v.43 no.3
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    • pp.312-323
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    • 2008
  • The purpose of this paper is to analyze thermal sensation which is measured by human physioclimatic reactions in South Korea. Relationships between Temperature-Humidity Index(THI) and human thermal sensation scale are derived from a questionnaire, which investigates degree of volunteer's thermal sensation with respect to each biometeorological condition. Analyses of these empirical relationships make it possible to calculate thermal sensational indices and to classify bioclimatic types for individual weather stations based on long-term(1971-2000) averages of monthly temperature and humidity data. A generalized annual physioclimatic maps for each Annual Cumulative Thermal Sensation Index for the 68 stations are constructed to show men tend to feel in various areas. The Monthly thermal sensations are affected by latitude, altitude, orographic effects and systems of airmasses. The Annual Cumulative Thermal sensations are increasing towards northern areas and inland, and that the major factors are largely derived from cold stress in winter. The Annual Physioclimatic Types are grouped 8 climatic types(M, ES, M-ES, M-S, W-ES, C-ES, C-M, C-M-ES) according to climatic stress. Results of this study can be applied for evaluation of thermal environment in our daily activities, and for searching relevant sports training-sites, climatherapy etc.

A Study on Premenstrual Syndrome (PMS), Nutrient Intake, Psychological Index according to the Obesity Degree of College Women (여대생의 비만도에 따른 월경전증후군 증상, 영양섭취 실태 및 심리지수 연구)

  • Kang, Se-Na;Park, Jung-Hwa;Hwang, Hye-Jin
    • Korean Journal of Community Nutrition
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    • v.16 no.1
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    • pp.14-22
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    • 2011
  • This study was designed to compare the incidence and severity of premenstrual syndrome (PMS) between normal (N = 85) and overweight or obese (N = 28) college female students and investigated correlation between PMS, nutrient intake, hematological index and psychological index (depression, anxiety, stress). Each subject was asked a Menstrual Discomfort Questionnaire (MDQ) for PMS by 5 Likert scale. The PMS scores of women in the normal weight subjects ranked in order of severity were water retention (2.71), followed by behavioral change (2.58), negative affect (2.46), pain (2.31), autonomic reaction (2.27), decreased concentration (2.16). The symptoms of 'pain' and 'behavioral change' of overweight or obese subject were significantly higher than those of normal subject (p < 0.05). And total cholesterol concentration of overweight or obese subjects was significantly higher than in normal subject (p < 0.05). There was a significant positive correlation (p < 0.05) between the symptoms of 'negative effect' and BMI. And the triglyceride concentration was positively related with 'water retention (p < 0.01)'. The symptoms of 'decreased concentration' were negatively correlated with calcium (p < 0.01) and vitamin B6 intake (p < 0.05). The depression score were positively related with symptoms of 'behavioral change (p < 0.05)', 'negative affect' (p < 0.01), and the anxiety score was positively correlated with 'behavioral change (p < 0.05)' and 'decreased concentration (p < 0.05)'. The stress score was positively correlated with 'decreased concentration (p < 0.01)', 'behavioral change (p < 0.05)' and 'negative affect (p < 0.05)'. This suggests that PMS represents the clinical manifestation of a calcium, vitamin $B_6$ deficiency and psychological disorder. Therefore we concluded that nutrient supplementation, depression and stress management may help to relieve PMS symptoms.