• Advances in concrete construction
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• v.9 no.1
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• pp.43-54
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• 2020

This paper presents an innovative stress-function variational approach in formulating the interfacial shear and normal stresses in an externally bonded concrete joint using carbon fiber-reinforced plastic (CFRP) plies. The joint is subjected to surface traction loadings applied at both ends of the concrete substrate layer. By introducing two interfacial shear and normal stress functions on the CFRP-concrete interface, based on Euler-Bernoulli beam idea and static stress equations of equilibrium, the entire stress fields of the joint were determined. The complementary strain energy was minimized in order to solve the governing equation of the joint. This yields an ordinary differential equation from which the interfacial normal and shear stresses were proposed explicitly, satisfying all the multiple traction boundary conditions. Lamination theory for composite materials was also employed to obtain the interfacial stresses. The proposed approach was validated by the analytic models in the literature as well as through a comprehensive computational code generated by the authors. Furthermore, a numerical verification was carried out via the finite element software ABAQUS. In the end, a scaling analysis was conducted to analyze the interfacial stress field dependence of the joint upon effective issues using the devised code.

• Journal of Integrative Natural Science
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• v.4 no.4
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• pp.332-338
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• 2011

This study was conducted to find associations of stress with obesity in female college students in Gwangju. 343 subjects were divided into two groups based on BMI(body mass index). BMI of normal group was $19.3{\pm}1.5$ while that of obese group was $26.4{\pm}3.6$. The measured stress level in obese subjects was higher and they were less capable of controlling obese oriented attitude compared to normal subject. Twenty four hour dietary recall revealed that nutrient intakes of obese subjects were higher in energy, lipid, P and cholesterol. However, they were more deficient in Ca, Fe and vitamin A, compared to those of normal ones. This study suggested severe stress might trigger undesirable dietary behavior leading to increase in food consumption which contribute to obesity. Effective nutrition education program targeting obese female students should be developed and implemented to relieve stress and practice desirable dietary behavior and eating pattern.

• Steel and Composite Structures
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• v.38 no.4
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• pp.415-430
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• 2021

The effective flange width was usually introduced into elementary beam theory to consider the shear lag effect in steel-concrete composite beams. Previous studies have primarily focused on the effective width under positive moments and elastic loading, whereas it is still not clear for negative moment cases in the normal service stages. To account for this problem, this paper proposed simplified formulas for the effective flange width and reinforcement stress of composite beams under negative moments in service stages. First, a 10-degree-of-freedom (DOF) fiber beam element considering the shear lag effect and interfacial slip effect was proposed, and a computational procedure was developed in the OpenSees software. The accuracy and applicability of the proposed model were verified through comparisons with experimental results. Second, a method was proposed for determining the effective width of composite beams under negative moments based on reinforcement stress. Employing the proposed model, the simplified formulas were proposed via numerical fitting for cases under uniform loading and centralized loading at the mid-span. Finally, based on the proposed formulas, a simplified calculation method for the reinforcement stress in service stages was established. Comparisons were made between the proposed formulas and design code. The results showed that the design code method greatly underestimated the contribution of concrete under negative moments, leading to notable overestimations in the reinforcement stress and crack width.

• The Journal of Korean Medicine
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• v.25 no.2
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• pp.194-206
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• 2004

Objectives : JiaoTeng-Yuan(교등원) is said to be a prescription for preservation of health in $\ulcorner$HuaTuo.ZhongZangJing (화타.중장경)$\lrcorner$. It is known to have the effect of Bu-Shen (보신: strengthening kidney) and Yi-Shou (익수: prolonging the span of one's life). This study investigates whether JTY is effective on inhibition of oxidation stress. Methods : Sprague-Dawley rats (12-week-old, weight $300{\pm}20g$) were divided into 3 groups. The normal group (n=8) was injected with PBS (1ml/body, s.c) subcutaneously behind the neck. The control group (n=8) was injected with D-galactose (50mg/kg, 1ml PBS/body, s.c) to induce pathological animals. The JTY group was injected with the same treatment as the control group, and fed containing JTY (10%). All groups were treated 1 time per day for 6 weeks. After the rats were sacrificed anti-oxidant enzyme (SOD, CAT, G-px) activity, GSH quantity of RBC and tissue (heart, liver and kidney), and plasma Vit-C quantity were examined. Also, the MDA levels of liver and kidney, lipofuscin of heart and endurance of erythrocyte membrane were measured. Results : In the JTY group, RBC's SOD activity decline was halted by 21 % of the normal level, compared to the control group, G-px activity (unit/g of Hb) increased significantly, compared to the normal group, and the level of Vit-C in plasma increased by 16%. Heart's SOD activity was kept at the same level as that of the normal group; and CAT activity decline was halted by 26%. Kidney's CAT and G-px activities were kept at the same level as that shown in the normal group, implying the existence of a halting effect. Liver also showed a slight halting effect against the decline of anti-oxidant ability, but the effect was not significant (${\alpha}=0.05$). A comparison between the levels of peroxide in SD rats showed that the level of TBARS in plasma increased significantly in the control group and that it was normal in the JTY group. The livers in the JTY group, compared to those in the control group, showed 36% halting effect of the normal level while their kidney's indicated the level significantly lower than the normal level. Heart's lipofuscin increased significantly in the control group, but was alike in both the JTY and the normal groups. Endurance of erythrocyte membrane (%) decreased significantly in the control group while it was kept at the similar level in both the JTY and the normal groups, indicating the halting effect. Conclusions : This study suggests that JTY is effective to defend oxidation stress caused by D-galactose in the animals. It showed that the anti-oxidant ability was maintained and strengthened. On the other hand, it reduced the level of peroxide in animals. In sum, JTY appeared to have the equilibrium normal physiological function in SD rat.

• Child Health Nursing Research
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• v.5 no.1
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• pp.5-17
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• 1999

This study was designed to determine the schemata and their characteristics of stress experience the subjectivity of stress experience(structure of subjectivity) would be a basic step for the effective clinical education through the stress management for characteristics of these types. Q-methodological method was used for that purpose. The research method statements were collected prior to the study through indepth interviews. For the study, 31 Q-statements were selected. There were 34 nursing students as subjects for the research. The 34 nursing students sorted the 31 statements using the principal of forced normal distribution. The principle of forced normal distribution, which has 9 scales to measure the individual opinions, was called. Q-factor analysis by using PC QUANL program supply the material. According to the outcomes of this study, there were 3 types of special opinion about the stress experience of clinical practice. The first type is called 'Influence of practical atmosphere type'. Members of this type experienced stress by an inadequate orientation and undesirable role model of nursing. The second type is called 'conflict of nursing role type'. Members of this type experienced stress by an inadequate orientation and undesirable role model of nursing. The third type is called 'Lack of confidence type'. Members of this type experienced stress because of a lack of confidence for their own nursing knowledge and skill. As a result, we now need further study to identify individual psychological aspects of stress for clinical practice. The findings will guide the development in effective approaches for clinical education. Finally, the result of the study will provide us the need for developing systematic and integrated practice education program for students and active involvement of clinical instructor.

• Korean Journal of Medicinal Crop Science
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• v.13 no.2
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• pp.103-109
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• 2005

When we carried out an anti-stress study using the extracts of A. senticosus, R. coreanus, F .japonica root, and A. fruticosa fruit grown in Korea, the results showed that blood cell counts returned to normal levels fastest with R. coreanus after stress application. The total WBC count was decreased in mice due to stress, whereas the number of lymphocytes was increased. The serum glucose level was higher in the control group compared with the comparative stress group. The weight of each organ to returning to normal level was significantly faster in those mice treated with the extracts compared with those in control groups. Especially, it even return to that of normal level with R. coreanus extract, suggesting that the administration of the plant extracts in this study would affect hormonal activities in the body to increase immune activities. F. japonica root that showed the highest anti-stress activities maybe effective for lipid and carbohydrate metabolism. These results would provide basic data to examine anti-stress effects of natural plants. Further in-depth studies could contribute in the development of functional plant materials with anti-stress activities.

• Speech Sciences
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• v.7 no.4
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• pp.49-57
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• 2000

This paper proposes an effective decision method focused on evaluating the 'stress position'. Conventional methods usually extract the acoustic parameters and compare them to references in absolute scale, adversely producing unstable results as testing conditions change. To cope with environmental dependency, the proposed method is designed to be model-based and determines the stressed interval by making relative comparison over candidates. The stressed/unstressed models are then induced from normal phone models by adaptive training. The experimental results indicate that the proposed method is promising, and that it is useful for automatic detection of stress positions. The results also show that generating the stressed/unstressed model by adaptive training is effective.

• Journal of the Korean Society of Safety
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• v.25 no.5
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• pp.44-53
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• 2010

Recently, the external prestressed concrete structures are increasingly being built. The mechanical behavior of prestressed concrete beams with unbonded tendon is different from that of normal bonded PSC beams in that the increment of tendon stress was derived by whole member behavior. By this reason, the ultimate stress of external tendon is smaller than that of bonded tendon or internal unbonded tendon. However, in the domestic and abroad code, the equation of ultimate stress of external tendon is not suggested yet, and the equation of ultimate stress of internal unbonded tendon is used instead of that of external tendon. Therefore, in this paper, after effective variables of ultimate stress of external tendon were analyzed, the analytical equation of ultimate stress of external tendon was proposed. And the reasonable coefficients were proposed by statistical work of test results of 25 beam with external tendon. Finally, the practical proposed equation of ultimate stress of external tendon was proposed with analytical and statistical model. The equation of ACI-318 and AASHTO 1994 were not matched with test results and had no correlations, and the proposed equation was well matched with test results. So the proposed equation in this paper will be a effective basis for the evaluation of external tendons in analysis and design.

• Korean Journal of Clinical Pharmacy
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• v.21 no.2
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• pp.131-137
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• 2011

The purpose of this study was to evaluate the clinical efficacy of a standardized special ethanol extract from Gynostemma pentaphyllum as a management for anxiety and stress of normal population. This is a two-arm, parallelgroup, randomized, double blind clinical trial comparing Gynostemma pentaphyllum extract 200 mg bid (GP-EX, n=48) or placebo bid (n=54). The main outcome measures were the decrease in anxiety sensitivity index (ASI), the State version (S-STAI) of the Stait-Trait Anxiety Inventory (STAI) and the Trait version (T-STAT) of the STAI from baseline over a 6 weeks treatment period. In more anxious group (S-STAI50 or ASI19), the anxiety in group with GP-EX was decreased significantly than one in normal population with placebo [S-STAI50: T-STAI = from $57.7{\pm}6.5$ ($mean{\pm}S.D.$) to $46.8{\pm}11.2$ in normal population with GP-EX, p=0.002 vs. from $54.1{\pm}9.9$ to $49.0{\pm}9.6$ in normal population with placebo, p>0.05; ASI19: T-STAI = from $47.2{\pm}12.0$ to $42.4{\pm}11.1$ in normal population with GP-EX, p=0.022 vs. from $48.7{\pm}11.5$ to $46.0{\pm}10.4$ in normal population with placebo, p>0.05]. The most frequently reported adverse reactions considered possibly related to treatment were mild gastrointestinal events. GP-EX is more effective than placebo and is well tolerated as a therapy for anxiety and stress of normal population.

• Journal of Power System Engineering
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• v.16 no.2
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• pp.43-48
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• 2012

Generally accelerated life test is well known as one method to reduce reliability qualification test period. This test is conducted under the higher stress condition than normal condition. So it can save the test time by calculating the acceleration factor from the relationship between the worst stress condition and normal condition. This paper investigates the worst stress condition for the accelerated life test to increase the acceleration factor. Especially, we focused on the method to obtain effective acceleration factors under the worst stress condition. Moreover, we considered how to decide the worst stress condition by looking for the operating limit of this system. The acceleration factor can be estimated from the ratio of the kinematic viscosity in the normal condition and the worst stress condition, the lowest temperature, by using Arrhenius relationship. Through some experiments for a refrigerator's compressor, we were able to confirm how to increase acceleration factors and how to reduce the reliability qualification test period with minimum samples.