• Structural Engineering and Mechanics
• /
• v.20 no.3
• /
• pp.335-346
• /
• 2005

The T-stress of cracks in elastic sheets is solved by using the fractal finite element method (FFEM). The FFEM, which had been developed to determine the stress intensity factors of cracks, is re-applied to evaluate the T-stress which is one of the important fracture parameters. The FFEM combines an exterior finite element model with a localized inner model near the crack tip. The mesh geometry of the latter is self-similar in radial layers around the tip. The higher order Williams series is used to condense the large numbers of nodal displacements at the inner model near the crack tip to a small set of unknown coefficients. Numerical examples revealed that the present approach is simple and accurate for calculating the T-stresses and the stress intensity factors. Some errors of the T-stress solutions shown in the previous literature are identified and the new solutions for the T-stress calculations are presented.

• International Journal of Advanced Culture Technology
• /
• v.8 no.2
• /
• pp.85-95
• /
• 2020

This study was a descriptive cross-sectional study using questionnaire that analyzed the relationship between stress coping types and life goals in the freshmen. The study period lasted from May 1, 2020 to May 20, 2020. A total of 282 people participated in the study, with freshmen enrolled in C and J provinces. The collected data were analyzed frequency, t-test, multiple regression, and Pearson correlation using SPSS 18.0. As a result, the passive(r=.202, p<0.05), aggressive(r=.243, p<0.05), Supportive(r=.255, p<0.01) and active stress coping types(r=.410, p<0.01) were correlated with achieve oriented life goal. And Supportive(r=.383, p<0.01), Active stress coping types(r=.497, p<0.01) were correlated with life oriented goal. According to gender, men (Mean 1.87, SD=0.62) had higher aggressive stress coping types than women (Mean=1.54, SD=0.52) (t=4.202, p=.000). People with achieve oriented life goals were found to have an effect on passive (t=7.176, p<0.01), aggressive (t=1.974, p<0.05) and evasive stress coping types (t=4.207, p<0.01). People with life oriented life goals were found to have ab effect on passive (t=6.331, p<0.01)), active stress coping types (t=2.101, p<0.05). In addition, passive (t=2.946, p<0.01), aggressive (t=4.067, p<0.01) and evasive stress coping types (t=2.624, p<0.01) affected achieve oriented goals, supportive stress coping types (t=5.438, p<0.01) affected the life oriented life goal, and active stress coping type affected on both achieve (t=4.061, p<0.01) and life oriented life goal (t=6.905, p<0.01).

• Computers and Concrete
• /
• v.30 no.1
• /
• pp.9-17
• /
• 2022

This paper discusses the effect of high temperatures (T_s) on the compressive strength and stress-strain curve of recycled fine aggregate concrete (RFAC), based on the experimental results. A total of 90 prisms (100 mm×100 mm×300 mm) were tested. The results show that the compressive strength and elastic modulus of RFAC specimens decreased significantly with increasing T values. As T increased, the strain corresponding to peak stress decreased first when T<200℃ and then increased afterwards. With increasing T values, the stress-strain curves became flat gradually, the peak stress dropped gradually, and ε_p decreased when T<200℃ and increased in the T range of 400-800℃. A stress-strain relations for RFAC exposed to high T_s is proposed, which agree quite well with the test results and may be used to practical applications.

• Journal of Korean Society for Quality Management
• /
• v.24 no.3
• /
• pp.19-30
• /
• 1996

We treat problems of estimating reliability R(t) = P[Y(t) ＞ X(t)] in the time dependent strength-stress model in which a unit of stress X(t) is subjected to environmental strength Y(t) at time t. In this paper we introduce a special model of R(t) with fixed strength and unaccumulated stress case, and propose a Mann-Whitney-Wilcoxon type estimator of R(t).

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.1
• /
• pp.121-126
• /
• 1994

A mutual integral, which has the conservation property, is applied to the problem of a crack in an isotropic elastic material. The stress intensity factors $K_{I}, K_{II}, K_{III}$ and T-stress for the problem in an infinite medium are easily obtained by using the mutual integral without solving the boundary value problem. The auxiliary solutions necessary in the proposed method are taken from the known asymptotic solutions. This method is amenable to numerical evaluation of the stress intensity factors and T-stress if the crack in a finite medium is considered.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.3
• /
• pp.324-332
• /
• 2022

The incidence of stress-related type 2 diabetes (stress-T2D), which is aggravated by physiological stress, is increasing annually. The effects of Lactobacillus, a key component of probiotics, have been widely studied in diabetes; however, studies on the effects of postbiotics are still limited. Here, we aimed to examine the mechanism through which heat-killed Lactiplantibacillus plantarum LRCC5314 (HK-LRCC5314) alleviates stress-T2D in a cold-induced stress-T2D C57BL/6 mouse model. HK-LRCC5314 markedly decreased body weight gain, adipose tissue (neck, subcutaneous, and epididymal) weight, and fasting glucose levels. In the adipose tissue, mRNA expression levels of stress-T2D associated factors (NPY, Y2R, GLUT4, adiponectin, and leptin) and pro-inflammatory factors (TNF-α, IL-6, and CCL-2) were also altered. Furthermore, HK-LRCC5314 increased the abundance of Barnesiella, Alistipes, and butyrate-producing bacteria, including Akkermansia, in feces and decreased the abundance of Ruminococcus, Dorea, and Clostridium. Thus, these findings suggest that HK-LRCC5314 exerts protective effects against stress-T2D via gut microbiome modulation, suggesting its potential as a supplement for managing stress-T2D.

• Journal of the Korean Data and Information Science Society
• /
• v.10 no.1
• /
• pp.111-118
• /
• 1999

We treat the problem of estimating reliability R(t) = P[Y(t) < X(t)] in the time dependent strength-stress model in which a unit of strength X(t) is subjected to environmental stress Y(t) at time t. In this paper two nonparametric approaches to estimate of R(t) are analyzed and compared with parametric method by simulation.

• Preventive Nutrition and Food Science
• /
• v.10 no.2
• /
• pp.151-155
• /
• 2005

This study was intended to investigate the effects of regular swimming exercise and vitamin C supplementation on the antioxidant system following exercise stress. For the swimming exercise experiment, a swimming adaptation exercise of 1 week was given to a group of 6-week-old mice. Following this, a swimming exercise for 8 weeks was conducted. The experimental group was divided into 3: a control group (C), a swimming exercise trained group (T), and a group of swimming + vitamin C supplementation (TC: vitamin supplementation: 1.3 mg/l00 g diet). After the swimming exercise, these group were further divided into those that had received the exercise stress for 2 hours and those that had not experienced exercise stress group. Then, the activities of the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) concentrations were measured. There was a lower weight increase in the T and TC groups than in the C group, and there was no significant difference between T and TC group. When exercise stress was not experienced, the activity of SOD was significantly increased in the TC group than in the T group, but there was no significant difference between C and T groups. The groups that had experienced a 2-hour exercise stress showed the SOD activity levels according to the following order, C < T < TC, with a significant difference between the three groups (p<0.05). There was no difference in MDA concentration amongst the experimental groups in non-exercise stress group. As well, there was no differences in MDA concentration between the C group and T group in the 2 hour exercise stress group. However, the TC group showed a MDA concentration level significantly lower than that of the T group. A significant increase in MDA concentration was observed in C group, when exercise stress was provided with no significant difference in the T and TC groups. As a result, regular exercise and vitamin C supplementation can be considered important in controlling the formation of lipid peroxides in exercise stress.

• Structural Engineering and Mechanics
• /
• v.73 no.2
• /
• pp.167-179
• /
• 2020

This study provides a simplified method for the evaluation of shear lag stress in rectangular box T-joints. The occurrence of shear lag phenomenon in the box T-joint generates stress concentration localized at both web-flange junctions of the beam, which leads to cracking or failure in the weld region of the joint. To prevent such critical circumstance, peak stress at the weld region is required to be checked during a preliminary design stage. In this paper, the shear lag stresses in the T-joints were evaluated using least-work solution in which the longitudinal displacements of the beam flange and web were presumed. The evaluation process considered particularly the effect of column flange flexibility, which was represented by an axial spring model, on the shear lag stress distribution. A simplified method for stress evaluation was provided to avoid solving complex mathematical problems using a stress modification factor β_s from a parametric study. The results showed that the proposed method was valid for predicting the shear lag stress in the box T-joints manually, as well compared with finite element results. The results are further summarized, discussed, and clarified that more flexible column flange caused higher stress concentration.

• Journal of Korean Academy of Nursing
• /
• v.29 no.6
• /
• pp.1392-1402
• /
• 1999

This study was carried out to find out stress-eating relationship in obese high school girls and to investigate the factors related to stress-induced eating. The conceptual framework used in this study was individual difference model. The research method was methodological triangulation. The data of the study were collected from purposively sampled 309 normal high school girls and 314 obese high school girls in S city. 15 volunteers, obese high school girls, enrolled in this qualitative research. Quantitative data was collected from May 6 to June 10, 1997 through questionnaires about stress and stress-related eating changes and from June 23 to August 26, 1997, qualitative data was collected. The results of the study were as follows : 1. Obese high school girls were unaffected by stress(t=-1.84, p=0.0662). 2. Through quantitative analysis, obese people divided into two groups in their response to stress. One group was composed of stress- eater. The other group was composed of non- stress eater. 3. Disinhibition(t=-3.1275, p=0.0019), cognitive restrain (t=-3.1597, p=0.0017), hunger(t=-3.5878, p=0.0004) were significantly different between stress-eaters and non-stress eaters. 4. According to the interview, 5 subjects of obese girls were stress eaters, and 10 subjects were non-stress eaters. Through qualitative research, the related factors of eating were eating attitude & behavior, stimuli situations on eating, and personality. In stress-eater group, they constantly went on a diet, however, they were prompted to eat when an uneasy feeling such as anxiety, depression, annoyance developed. Their personality were entirely optimistic. Whereas non-stress eater group had no interest in diet and didn't appear to have psychological factors to stimulate eating in stressful situations. Their personality was not only optimistic but also keenly characteristic. 5. To compare obese-normal high school girls on the effect of stress in eating. Normal weigh high school girls decreased their eating when stressed(t= -13.62, p=0.0001). In conclusion, this study suggests that there are two different groups in obese high school girls in regards to eating responses on stressful situations. As a result of these finding, clinical and school nurses can detect the stress-eaters who need stress management intervention, and can apply appropriate management program according to the individual needs.