• Journal of Welding and Joining
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• v.34 no.4
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• pp.28-33
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• 2016

The purpose of this study is to evaluate the redistribution of transverse residual stress in the multi-pass FCA butt weld of YP47 in the hatch coaming top plate of ultra large size containership under the tensile cyclic load. In order to do it, the configuration of modified H type specimen including restraint length was first designed to simulate the restraint condition of the butt weld in hatch coaming top plate. FE analysis procedure for evaluating the transverse residual stress was verified by comparing the calculated mean and surface residual stresses with the measured results in the test specimen. After that, the effect of the cyclic load on the redistribution of transverse residual stress was evaluated by comprehensive FEA. From the results, it was found that although the maximum transverse residual stress decreased with an increase in the applied maximum load, the effect of the cyclic load on the mean residual stress is small enough to be negligible. It is because the maximum stress of the ship corresponding to the probability of 10E-8 is less than 70% of yield stress of the weld.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5A
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• pp.317-325
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• 2012

In this study, to evaluate the shrinkage behavior of ultra high performance fiber reinforced concrete (UHPFRC) under restrained condition, restrained shrinkage test was performed according to ring-test mostly used at home and abroad. Ring-test was performed with the various thicknesses and radii of inner steel ring to give different degree of restraint. Free shrinkage and tensile tests were carried out simultaneously to estimate the degree of restraint, stress relaxation, and shrinkage cracking potential. Test results indicated that the average steel strain and residual tensile stress were reduced as the thicker inner steel ring was used, whereas degree of restraint was increased. The steel strain, residual tensile stress and degree of restraint were hardly affected by the size of radius of inner ring. In the case of all ring specimens, shrinkage crack did not occur because the residual tensile stress was lower than the tensile strength. About 39~65% of the elastic shrinkage stress was relaxed by the sustained interface pressure, and the maximum relaxed stress was increased as the thicker inner ring was applied. Finally, the degree of restraint with age was predicted by performing non-linear regression analysis, and it was in good agreement with the test results.

• Applied Microscopy
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• v.38 no.3
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• pp.213-219
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• 2008

The plasticity of nervous system is generated not only due to changes in neurons but also due to changes in neuroglial cells. Astrocyte is important for maintaining the normal brain function and controlling the neuronal functions. The amygdala receives an array of important sensory information of danger signals. This information is further transduced and integrated to produce the highly adaptive emotion, fear. In this study, morphometric changes in the cell bodies of astrocytes in the amygdala, induced by prenatal stress and restraint stress were examined. For this purpose. rats were classified into 4 groups; control group (CON), only restraint-stressed (starting on P90 for 3 days) group (CONR), prenatally-stressed group (PNS), and prenatally and restraint (on P90 for 3 days) stressed group (PNSR). Astrocytes were verified with anti-GFAP immunohistochemistry, counter stained with methylene blue/azure II and were examined using the Neurolucida. Results showed that astrocytes in the amygdala of PNS rats had significantly larger cell bodies than did CON rats and this was enhanced further by restraint stress. Thus this data showed that hypertrophy of the astrocytic cell bodies of amygdala complex is induced by prenatal and restraint stress.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.5
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• pp.393-403
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• 2013

Baicalein (BA), a plant-derived active flavonoid present in the root of Scutellaria baicalensis, has been widely used for the treatment of stress-related neuropsychiatric disorders including depression. Previous studies have demonstrated that repeated restraint stress disrupts the activity of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in depression. The behavioral and neurochemical basis of the BA effect on depression remain unclear. The present study used the forced swimming test (FST) and changes in brain neurotransmitter levels to confirm the impact of BA on repeated restraint stress-induced behavioral and neurochemical changes in rats. Male rats received 10, 20, or 40 mg/kg BA (i.p.) 30 min prior to daily exposure to repeated restraint stress (2 h/day) for 14 days. Activation of the HPA axis in response to repeated restraint stress was confirmed by measuring serum corticosterone levels and the expression of corticotrophin-releasing factor in the hypothalamus. Daily BA administration significantly decreased the duration of immobility in the FST, increased sucrose consumption, and restored the stress-related decreases in dopamine concentrations in the hippocampus to near normal levels. BA significantly inhibited the stress-induced decrease in neuronal tyrosine hydroxylase immunoreactivity in the ventral tegmental area and the expression of brain-derived neurotrophic factor (BDNF) mRNA in the hippocampus. Taken together, these findings indicate that administration of BA prior to the repeated restraint stress significantly improves helpless behaviors and depressive symptoms, possibly by preventing the decrease in dopamine and BDNF expression. Thus, BA may be a useful agent for the treatment or alleviation of the complex symptoms associated with depression.

• Herbal Formula Science
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• v.30 no.2
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• pp.85-93
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• 2022

Objectives : This study investigated anti-inflammatory effects of Nardotidis seu Sulculii Concha water extract (NSCE) against restraint-induced stress. Methods : In vivo, NSCE was orally administered to male white mice at concentrations of 250 mg/kg and 500 mg/kg for 3 days, and then restraint-induced stress was induced for 6 hours. The level of liver damage was measured by serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH). The stress-related hormones such as cortisol and corticosterone were measured by ELISA assay. Also, western blot analysis was performed to detect expression of mitogen-activated protein kinase (MAPK) and cyclooxygenase-2 (COX-2) proteins. Pathological changes were observed by hematoxylin and eosin (H&E) staining of the liver tissue, and Immunohistochemical (IHC) staining was performed to examine liver inflammation through macrophage infiltration. Results : The AST, ALT, LDH and the stress related hormones such as cortisol and corticosterone were significantly decreased in the NSCE treated group compared with stress group. In histological analysis, H&E staining of liver tissues did not detect the hepatic injury or damage in all groups. As a result of IHC staining, it was confirmed that infiltration of macrophages was increased in the stress-induced group, but decreased in the group treated with NSCE. The COX-2 and MAPK proteins expression was significantly increased by restraint-induced stress, but these proteins were decreased in the NSCE treated group. Conclusions : These results suggest that NSCE has the anti-inflammatory activity in restraint-induced stress model, and it is believed that NSCE can be used for the prevention of liver inflammation.

• Journal of Welding and Joining
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• v.28 no.4
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• pp.33-40
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• 2010

The purpose of this study is to establish a predictive equation of transverse residual stress at the thick FCA butt weldment of large container vessel. The variables used were restraint degree, yield strength of base material, thickness of weldment and welding heat input. Restraint degree at the thick weldment of container ship having the various welding sequence was calculated using FEA. From the result, the H-type specimen was designed to reproduce the level of restraint degree at the actual weldment of containership. Based on the results, the predictive equations of the mean value and the distribution of transverse residual stress at each location of the weldment were established using dimensional analysis and multiple-regression method. The predictive equations were verified by comparing with those measured by XRD in the actual weldment of the ship.

• Journal of Welding and Joining
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• v.33 no.6
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• pp.6-12
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• 2015

Thermal fatigue life of the automobile exhaust manifold is directly affected by the restraint force according to the structure of exhaust system and bead shape of the welded joints. In the present study, the microstructural changes and precipitation behavior during thermal fatigue cycle of the 18wt% Cr ferritic stainless steel weld heat affected zone (HAZ) considering restraint stress were investigated. The simulation of weld HAZ and thermal fatigue test were carried out using a metal thermal cycle simulator under complete constraint force in the static jig. The change of the restraint stress on the weld HAZ was simulated by changing the shape of notch in the specimen considering the stress concentration factor. Thermal fatigue properties of the weld HAZ were deteriorated during cyclic heating and cooling in the temperature range of $200^{\circ}C$ to $900^{\circ}C$ due to the decrease of Nb content in solid solution and coarsening of MX type precipitates, laves phase, $M_6C$ with coarsening of grain and softening of the matrix. As the restraint stress on the specimen increased, the thermal fatigue life was decreased by dynamic precipitation and rapid coarsening of the precipitates.

• Journal of Oriental Neuropsychiatry
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• v.32 no.1
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• pp.25-37
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• 2021

Objectives: Depression is a mood disorder showing low energy, loss of interest, anhedonia, and anxiety. It affects a patients' daily life. This disease is considered a social problem because the patient may commit suicide in extreme cases. JSB is composed of 12 Korean medicinal herbs. It has been prescribed to patients with depression. The objective of this study is to investigate anti-depressive effects of JSB on restraint stress-induced depression in a mouse model. Methods: Depression was induced by restraint stress. Mice were orally administered JSB at 10, 20, or 40 mg/kg for 14 days. Forced swimming test (FST) and open field test (OFT) were performed. Brain-derived neurotrophic factor (BDNF) mRNA level was measured by real time-PCR. Plasma levels of corticosterone and serotonin were measured by ELISA. Blood levels of AST and ALS were measured using a biochemical analyzer. Results: JSB treatment significantly reduced the immobility time in FST. BDNF mRNA level was increased by JSB treatment in the hippocampi of mice. Although the expression of TNF-α was also increased by JSB, such increase was not statistically significant. The increase of corticosterone level in plasma induced by restraint stress was significantly down-regulated by JSB. JSB reduced blood level of AST, but not ALT. Conclusions: JSB has a potential to manage depression, setting a foundation for clinical application of Korean medicine with safety.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.86-93
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• 2007

The restraint force is required for the accurate measurement and analysis to protect weldment from residual stress. Also, this residual stress caused by cracks in weldments is often observed in the weldments of large size nozzles or radial tanks after welding. This paper is preformed to evaluate the welding restraint forces using load cell with STS304 thin plate which is used as the pressure vessel steel in the industry field. As a result, as the welding currents are higher and the welding speeds are more slowly, the magnitude of restraint force in process of the flat plate welding shows to be more large.

• Nuclear Engineering and Technology
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• v.39 no.1
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• pp.75-84
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• 2007

This paper presents a closed-form model for evaluating the restraint effect of pressure induced bending on the opening of a circumferential through-wall crack, which is considered plastic deformation behavior. Three-dimensional finite element analyses with different crack lengths, restraint conditions, pipe geometries, magnitudes of internal pressure, and tensile properties were used to investigate the influence of each parameter on the pressure-induced bending restraint on the crack opening displacement. From these investigations, an analytical model based on elastic-perfectly plastic material was developed in terms of the crack length, symmetric restraint length, mean radius to thickness ratio, axial stress corresponding to the internal pressure, and normalized crack opening displacement evaluated from a linear-elastic crack opening condition. Finite element analyses results demonstrate that the proposed analytical model reliably estimated the restraint effect of pressure-induced bending on the plastic crack opening of a circumferential through-wall crack and properly reflected the dependence on each parameter within the range over which the analytical expression was derived.