• Geomechanics and Engineering
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• v.18 no.5
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• pp.459-469
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• 2019

It is important to estimate the shear strength of shallow compacted soils as a construction material. A series of constant water content triaxial compression (CWCC) tests under low confining state in this study were performed on compacted geomaterials. For establishing a relationship of the shear strengths between saturated and unsaturated states on compacted geomaterials, the suction stresses were derived by two methods: the conventional suction-measured method and the Suction stress-SWRC Method (SSM). Considering the suction stress as an equivalent confining stress component in the (${\sigma}_{net}$, ${\tau}$) plane, it was found that the peak deviator stress states agree well with the failure line of the saturated state from the triaxial compression test when the SSM is applied to obtain the suction stress. On the other hand, the cavitation phenomenon on the measurement of suction affected the results of the conventional suction-measured method. These results mean that the SSM is distinctly favorable for obtaining the suction value in the CWCC test because the SSM is not restricted by the cavitation phenomenon. It is expected that the application of the SSM would reduce the time required, and the projected cost with the additional equipment such as a pore water measuring device in the CWCC test.

• The Korean Journal of Emergency Medical Services
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• v.4 no.1
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• pp.73-81
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• 2000

This is a study to evaluate the effects of the stress and figure out the cause of them, I surveyed 400 students (male 257 and female 143) of health sciences colleges from 15th October to 23th October 1999. The major instruments of this study were Korean Style Self-Analysis Stress Opinionnaire. This Questionnaire contains 5 items which measure stress and health opinions or attitudes. The data were analyzed by the path analysis - with SPSS and AMOS package program. The result are as follows : 1. In the comparison of stress by sex, a potential group is highest for both of male and female (male 35.7%, female 64.3%). In high risk group, male is 10.6% and female 13.0%. In potential risk group, male is 4.1% and female 7.6%. 2. It have suggested that students' stress factors much affected with physical health and psychological health in school life(Y(Stress) = $0.813{\times}1$(Health) - $0.381{\times}2$(Mind Health) + $0.118{\times}3$(School Social) + $0.100{\times}4$(Confidence) - $0.061{\times}5$(Happiness Social)+E).

• Journal of Aquaculture
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• v.20 no.1
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• pp.60-64
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• 2007

We examined the effects of the vibration stress on oxygen consumption and ammonia excretion of cultured soft-shelled turtle, Pelodiscus sinensis. For the stressed group vibration of $45{\sim}78\;dB$ (V) from electric vibrator was turned on for 15 min with 2-h intervals during daytime hours ($08:00{\sim}18:00$) for 28 days. Two different sizes of soft-shelled turtle, large (carapace length: $12{\sim}16\;cm$, body weight: $300{\sim}600\;g$, large size turtle: LST) and middle ($16{\sim}20\;cm,\;700{\sim}1,000\;g$, middle size turtle: MST) were used. The oxygen consumption of LST the beginning of the experiment (1 day) was 124.30 mg $O_2/kg/hr$, and after 7, 14, 21 and 28 days of stress decreased by 47.2, 71.6, 79.1 and 86.0%, respectively. In MST, oxygen consumption of beginning day was 66.04 mg $O_2/kg/hr$, and after 28 days of stress decreased by 76.5%. Ammonia nitrogen excretion showed a similar pattern to that of oxygen consumption. Ammonia nitrogen excretion of beginning of the experiment was 0.537 mg N/kg/hr, and after 28 days of stress decreased by 75.4% for LST, and by 74.3% for the middle ones. From in this study it was showed that the physiological activity was reduced by 50% following 8.4 days of vibration stress for LST, and 15.5 days for MST.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1401-1410
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• 1996

This paper present a method to predict fatigue life of a construction equipment performing static stress analysis and dynamic stress analysis using the computer simulation for proto and pilot type model. The parameter of design variable is used for finite elemt modeling of a excavator. Desinger can design reliable product and shorten lead time by using "Simulation System for Front Attachment of Excavator" develped in this study.his study.

• Women's Health Nursing
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• v.20 no.1
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• pp.83-91
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• 2014

Purpose: The purpose of this study was to identify relationships of resilience, Post-Traumatic Stress Disorder(PTSD), and quality of life of breast cancer patients. The findings from this study would provide baseline data needed for nursing intervention. Methods: A sample of 129 breast cancer patients was recruited from three hospitals in J and C cities in Korea. The survey was conducted with participants by utilizing self-reported questionnaires. Results: Quality of life showed statistically significant differences on religion (t=2.11, p=.033) and hobby (t=2.79, p=.006). Resilience and PTSD had a negative correlation (r=-.22, p=.010). Resilience and quality of life of the participants had a positive correlation (r=.58, p<.001), whereas PTSD and quality of life had a negative correlation (r=-.45, p<.001). Significant predictors of quality of life were resilience and PTSD. These variables explained 44.9% of the variance in quality of life. Conclusion: Findings indicate that as resilience of breast cancer patients rose higher and PTSD got lower, their quality of life increased. Based on these results, nursing interventions directed towards improving resilience and relieving PTSD is proposed.

• Weed & Turfgrass Science
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• v.2 no.3
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• pp.254-259
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• 2013

The mechanisms of resistance to oxyfluorfen (OF) and paraquat (PQ) were investigated in rice plants. Examination of the concentration dependence of oxyfluorfen- or paraquat-induced increase in conductivity showed that conductivities in the OF- and PQ-treated leaf squares were increased with 0.1 ${\mu}M$ oxyfluorfen and 0.01 ${\mu}M$ paraquat and further increased with higher concentrations. The levels of conductivity were approximately 10-times higher in the PQ-treated plants than in the OF-treated plants, indicating that the PQ-treated plants suffered more severe photodynamic damage than the OF-treated plants. The photooxidative stress caused by foliar application of either 50 ${\mu}M$ oxyfluorfen or 100 ${\mu}M$ paraquat increased the enzyme activities of ascorbate peroxidase and peroxidase 1 day after the herbicide treatments and then further increased their enzyme activities 2 days after the treatments. The activities of catalase began to increase 2 days after the oxyfluorfen and paraquat treatments. These antioxidant enzymes appear to play an essential part of defense mechanisms against oxyfluorfen and paraquat. Our results demonstrate that paraquat caused more severe oxidative stress, as indicated by a greater change in conductivity, thereby resulting in greater increases in antioxidant responses in plants, compared with those of oxyfluorfen.

• Journal of Ocean Engineering and Technology
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• v.20 no.6 s.73
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• pp.123-129
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• 2006

The mechanical properties of bellows, such as the extensibility and the strength can be changed depending on the shape. For the shipbuilding material, it is desirable that the fatigue life is long due to the elastic property and the reduction of thermal stress in piping system. Nowadays, the domestic production and design of bellows are based on the E.J.M.A. Code. Therefore, the design standard is in need because of much errors and lack of detailed analysis. In this study, it is attempted to find out the optimal shape of U-type bellows using the finite element analysis. The design factors, mountain height, length, thickness, and the number of convolutions are considered and the proper values are chosen for the simulation. The results shaw that as the number of convolutions reduces, the volume decreases while the stress increases. However, as the number of convolutions increases, the volume increases above the standard volume and the stress obviously increases. In addition, the effect of the thickness of bellows on the stress is very large. Both of the mass and stress are decreasing at a certain lower value region. Also, we investigated shape optimization with considering maximum stress distribution tendency.

• Biomolecules & Therapeutics
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• v.24 no.1
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• pp.33-39
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• 2016

Oxidative stress activates several intracellular signaling cascades that may have deleterious effects on neuronal cell survival. Thus, controlling oxidative stress has been suggested as an important strategy for prevention and/or treatment of neurodegenerative diseases. In this study, we found that ginsenoside Rh1 inhibited hydrogen peroxide-induced reactive oxygen species generation and subsequent cell death in rat primary astrocytes. Rh1 increased the expression of phase II antioxidant enzymes, such as heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1, superoxide dismutase-2, and catalase, that are under the control of Nrf2/ARE signaling pathways. Further mechanistic studies showed that Rh1 increased the nuclear translocation and DNA binding of Nrf2 and c-Jun to the antioxidant response element (ARE), and increased the ARE-mediated transcription activities in rat primary astrocytes. Analysis of signaling pathways revealed that MAP kinases are important in HO-1 expression, and act by modulating ARE-mediated transcriptional activity. Therefore, the upregulation of antioxidant enzymes by Rh1 may provide preventive therapeutic potential for various neurodegenerative diseases that are associated with oxidative stress.

• Journal of Preventive Medicine and Public Health
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• v.31 no.4 s.63
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• pp.728-739
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• 1998

To improve wellness and quality of life by recognizing the health efforts of stress, the author estimated the relationships between stress, subjective symptoms and clinical diagnosis through a questionnaire and a battery of specified laboratory tests; electrocardiography, blood pressure, cholesterol, aspartate aminotransferase(AST), alanine aminotransferase(ALT), gamma glutamyl transferase$(\gamma-GTP)$, fasting blood sugar, gastro-endoscopy or UGI, abdominal sonography, etc. The data was gathered from 337 clients who were undergoing multiphasic screening program at a University Hospital from January to March 1998. The mean age of subjects was $46.5{\pm}11.2$ years and the mean of body mass index was $24.0{\pm}3.7kg/m^2$. The mean vol of stress was $18.5{\pm}6.0$ expressed as the score out of 40. By general characteristics and lift style among male, mean level of stress was significantly higher in case of lower socioeconomic status, habitual drug use, longer daily working time(>10 hours), no regular exercise, drinkers, irregular meal, skip-ping breakfast(p<0.05). In case of female, that was significantly higher in case of lower education, lowe. socioeconomic status, longer daily working time(>10 hours), no regular exercise, drinkers, smokers, irregular meal, skipping breakfast(p<0.05). Significant correlations were observed between stress and subjective symptoms in all kinds of organ system (p<0.01). Correlation coefficients of stress among male were relatively high with neuro-psychiatric symptom$(\gamma=0.476)$ and cardio-vascular symptom$(\gamma=0.361)$ in order, and correlation coefficients of stress among female was highest with neuro-psychiatric symptom$(\gamma=0.371)$. The prevalence of the diagnosis through the battery of laboratory tests was high in upper gastrointestinal disorders and hypercholesterolemia in order in both sex group. Among male the mean score of stress was significantly high in ulcerative peptic disorder of upper gastrointestine and hepatopathy in order (p<0.05) . Among female that was significantly high in diabetes mellitus. In summary, it is likely that there are associations between stress, subjective symptoms and clinical diagnosis. To promote wellness and quality of life it would be of value that periodic stress evaluation program and stress management including apropriate control of smoking and drinking, regular exercise and meal.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.153-158
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• 2005

Titanium alloy has widely been used as material for automotive parts because it has high specific strength. It is also light and harmless to human body. But, we have little design data about the creep behaviors of the alloy. Therefore, in this study, creep tests under four constant stress conditions have been conducted with low different temperature conditions. A series of creep tests had been performed to get the basic design data and life prediction of titanium products and we have gotten the fallowing results. First, the stress exponents decrease as the test temperatures increased. Secondly, the creep activation energy gradually decrease as the stresses became bigger. Thirdly, the constant of Larson-Miller parameter on this alloy was estimated as about 7.5. And for the last, the fractographs at the creep rupture showed the ductile fracture due to the intergranullar rupture.