• Computers and Concrete
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• 제17권5호
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• pp.639-653
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• 2016

The present article discusses the effect of the ratio of bridge surface to total shear surface, number of bridge areas and normal stress on the failure behavior of the planar non-persistent open joints. Totally, 38 models were prepared using plaster and dimensions of $15cm{\times}15cm{\times}15cm$. The bridge area occupied $45cm^2$, $90cm^2$ and $135cm^2$ out of the shear surface. The number of rock bridges increase in fixed area. Two similar samples were prepared on every variation in the rock bridges and tested for direct shear strength under two high and low normal loads. The results indicated that the failure pattern and the failure mechanism is mostly influenced by the ratio of bridge surface to total shear surface and normal stress so that the tensile failure mode change to shear failure mode by increasing in the value of introduced parameters. Furthermore, the shear strength and shear stiffness are closely related to the ratio of bridge surface to total shear surface, number of bridge areas and normal stress.

• 방사성폐기물학회지
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• 제21권4호
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• pp.559-570
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• 2023

The aim of this study is to ensure the structural integrity of a canister to be used in a dry storage system currently being developed in Korea. Based on burnup and cooling periods, the canister is designed with 24 bundles of spent nuclear fuel stored inside it. It is a cylindrical structure with a height of 4,890 mm, an internal diameter of 1,708 mm, and an inner length of 4,590 mm. The canister lid is fixed with multiple seals and welds to maintain its confinement boundary to prevent the leakage of radioactive waste. The canister is evaluated under different loads that may be generated under normal, off-normal, and accident conditions, and combinations of these loads are compared against the allowable stress thresholds to assess its structural integrity in accordance with NUREG-2215. The evaluation result shows that the stress intensities applied on the canister under normal, off-normal, and accident conditions are below the allowable stress thresholds, thus confirming its structural integrity.

• Geomechanics and Engineering
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• 제35권5호
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• pp.475-486
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• 2023

Ballast particles have an irregular shape and are discrete in nature. Due to the discrete nature of ballast, it exhibits complex mechanical behaviour under loading conditions. The discrete element method (DEM) can model the behaviour of discrete particles under a multitude of loading conditions. DEM is used in this paper to simulate a series of three-dimensional direct shear tests in order to investigate the shear behaviour of railway ballast and its interaction at the microscopic level. Particle flow code in three dimension (PFC3D) models the irregular shape of ballast particles as clump particles. To investigate the influence of particle size distribution (PSD), real PSD of Indian railway ballast specification IRS:GE:1:2004, China high-speed rail (HSR) and French rail specifications are generated. PFC3D built-in linear contact model is used to simulate the interaction of ballast particles under various normal stresses, shearing rate and shear box sizes. The results indicate how shear resistance and volumetric changes in ballast assembly are affected by normal stress, shearing rate, PSD and shear box size. In addition to macroscopic behaviour, DEM represents the microscopic behaviour of ballast particles in the form of particle displacement at different stages of the shearing process.

• 대한한의학회지
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• 제24권1호
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• pp.155-168
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• 2003

This study was carried out to investigate the effect of Keuibi-tang (KBT) on the injury of gastric mucous membrane by stress and ethanol in mice. The normal group was non-inflammation elicited mice. The two control groups were mice with gastro-inflammation elicited by stress and ethanol. The two sample groups were mice administered KBT before gastro-inflammation elicitation. In the common morphology and histochemical change, the two control groups were observed with various injuries such as hemorrhagic erosion and ulcer, while the sample group was the same as the normal group. In the immunohistochemical change, the distributions of PNA and COX-1 treated with KBT noticeably increased over the control group (P<0.05). The distributions of $NF-{\kappa}B$ p50, COX-2 and TUNEL in the group treated with KBT were noticeably lower than in the control group (P<0.05). The distribution of KBT was the same as the normal group. According to the above results, it is supposed that KBT is applicable to gastritis and gastric ulcer due to stress and alcoholic drinks.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1481-1486
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• 2007

Frictional laws are criticized with emphasis on their application to bulk metal forming simulation in this paper. Coulomb frictional law and constant shear frictional law are investigated in detail in terms of their effect on metal forming process. A friction sensitive bulk metal forming process, a long-pipe simultaneously shrinking and expanding process, is introduced and the problems of the constant shear frictional law are revealed comparing the predictions obtained by the Coulomb frictional law and the constant shear frictional law with the experiments. It is shown that the constant shear frictional law is improper in the case that the normal stress varies very much from position to position and that the normal stress is low compared with flow stress of the adjacent material. It is also shown that the Coulomb frictional constant is more or less affected by the normal stress.

• 정신신체의학
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• 제11권2호
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• pp.159-169
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• 2003

연구목적: 본 연구의 목적은 소아암 환아 부모와 일반 부모 사이의 스트레스와 삶의 질을 비교하는 데 있다. 방 법: 스트레스 인자지각는 전반적인 스트레스평가 척도(global assessment of recent stress)를, 스트레스 반응(정신병리)은 간이정신진단척도(Symptom checklist-90-revised)를 이용하였다. 대응전략은 대응척도를 이용하였으며, 삶의 질은 스미스클라인비참 삶의 질 척도를 이용하였다. 결 과: 소아암 환아 부모군은 대인관계, 관계의 변화, 질병 및 상해, 경제적 문제, 비일상적인 사건 등과 관련한 스트레스인자 지각점수가 대조군보다 각각 유의하게 더 높았다. 대응전략에서는 소아암 환아 부모군이 대조군보다 자기 통제, 긍정적 재평가 점수가 각각 유의하게 더 높았다. 정신병리에서는 소아암 환아 부모군이 대조군보다 불안, 우울, 신체화, 공격성 점수가 각각 유의하게 더 높았다. 삶의 질 척도 점수는 소아암 환아 부모군이 대조군보다 유의하게 더 낮았다. 급성 백혈병 환아 부모 사이의 비교에서 대응전략에서는 ANLL 환아 부모가 ALL 환아 부모보다 거리감두기, 책임수용 점수가 각각 유의하게 더 높았다. 정신병리에서 ANLL 환아부모가 ALL 환아 부모보다 우울 점수가 유의하게 더 높았다. 결 론: 소아암 환아 부모들이 높은 스트레스 지각과 낮은 삶의 질을 보고하고 있으므로 이에 대한 스트레스 관리프로그램 등 정신사회적 개입이 필요하다.

• Journal of Nutrition and Health
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• 제43권3호
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• pp.285-293
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• 2010

This study investigated the body image, body stress, eating attitude, and dietary quality in middle school girls. Questionnaires were administered to one hundred fifty seven middle school girls in Seoul area. The subjects were categorized into the five groups according to their body mass index (BMI); 1) severely under-weight (BMI < 16.5 $kg/m^2$), 2) under-weight (16.5 $\leq$ BMI < 18.5 $kg/m^2$), 3) normal weight (18.5 $\leq$ BM I < 23.0 $kg/m^2$), 4) overweight (23.0 $\leq$ BMI < 25.0 $kg/m^2$), and 5) obese (BMI $\geq$ 25 $kg/m^2$). 7.0%, 14.6%, 58.9%, 10.2%, and 10.2% of the subjects were classified as severely under-weight, under-weight, normal weight, overweight and obese groups, respectively. Regardless of the BMI, the subjects had disturbed body image, body stress, and poor eating attitude. The actual BMIs of the normal weight, overweight and obese subjects were significantly different from their desired BMI and perceived BMI, representing these subjects dissatisfied their body shape. Almost all subjects tried to lose their body weight even in the severely under-weight and under-weight groups. There were significant correlations of BMI with body image disturbance (p < 0.05), body stress (p < 0.01) and eating attitude (p < 0.05). These results indicated that middle school girls who have higher BMI seemed to have more body image distortion, body stress and risk of eating disorder. However, any significant difference in dietary quality among the five groups was not observed even though their dietary patterns were not balanced. As a conclusion, it is required that middle school girls should correct their distorted body image and body stress. Also, efforts to improve eating attitude, dietary pattern and nutritional status in the middle school girls are needed.

• Nutrition Research and Practice
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• 제7권6호
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• pp.430-438
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• 2013

Increased oxidative stress in obese diabetes may have causal effects on diabetic complications, including dyslipidemia. Lipopolysccharides (LPS) along with an atherogenic diet have been found to increase oxidative stress and insulin resistance. Cranberry has been recognized as having beneficial effects on diseases related to oxidative stress. Therefore, we employed obese diabetic animals treated with an atherogenic diet and LPS, with the aim of examining the effects of cranberry powder (CP) on diabetic related metabolic conditions, including lipid profiles, serum insulin and glucose, and biomarkers of oxidative stress. Forty C57BL/KsJ-db/db mice were divided into the following five groups: normal diet + saline, atherogenic diet + saline, atherogenic diet + LPS, atherogenic diet + 5% CP + LPS, and atherogenic diet + 10% CP + LPS. Consumption of an atherogenic diet resulted in elevation of serum total cholesterol and atherogenic index (AI) and reduction of high density lipoprotein (HDL)-cholesterol. However, with 10% CP, the increase in mean HDL-cholesterol level was close to that of the group with a normal diet, whereas AI was maintained at a higher level than that of the group with a normal diet. LPS induced elevated serum insulin level was lowered by greater than 60% with CP (P < 0.05), and mean serum glucose level was reduced by approximately 19% with 5% CP (P > 0.05). Mean activity of liver cytosolic glutathione peroxidase was significantly increased by LPS injection, however it was reduced back to the value without LPS when the diet was fortified with 10% CP (P < 0.05). In groups with CP, a reduction in mean levels of serum protein carbonyl tended to occur in a dose dependent manner. Particularly with 10% CP, a reduction of approximately 89% was observed (P > 0.05). Overall results suggest that fortification of the atherogenic diet with CP may have potential health benefits for obese diabetes with high oxidative stress, by modulation of physical conditions, including some biomarkers of oxidative stress.

• Structural Engineering and Mechanics
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• 제47권2호
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• pp.185-207
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• 2013

In flexural strength design of normal-strength concrete (NSC) beams, it is commonly accepted that the distribution of concrete stress within the compression zone can be reasonably represented by an equivalent rectangular stress block. The stress block it governed by two parameters, which are normally denoted by ${\alpha}$ and ${\beta}$ to stipulate the width and depth of the stress block. Currently in most of the reinforced concrete (RC) design codes, ${\alpha}$ and ${\beta}$ are usually taken as 0.85 and 0.80 respectively for NSC. Nonetheless, in an experimental study conducted earlier by the authors on NSC columns, it was found that ${\alpha}$ increases significantly with strain gradient, which means that larger concrete stress can be developed in flexure. Consequently, less tension steel will be required for a given design flexural strength, which improves the ductility performance. In this study, the authors' previously proposed strain-gradient-dependent concrete stress block will be adopted to produce a series of design charts showing the maximum design limits of flexural strength and ductility of singly-and doubly-NSC beams. Through the design charts, it can be verified that the consideration of strain gradient effect can improve significantly the flexural strength and ductility design limits of NSC beams.

• 지역사회간호학회지
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• 제21권3호
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• pp.333-340
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• 2010

Purpose: The purpose of this study was to examine the bone mineral density (BMD), body mass index (BMI), stress, and health promotion lifestyle of female college students and to assess relations among them. Methods: A total of 220 female college students were assessed through anthropometric measurements and bone mineral density test using quantitative ultrasound. In addition, the subjects were asked about stress and health promotion lifestyle with a self-rating questionnaire. Collected data were processed with the SPSS/WIN 12.0 program. Results: 1) Of the students, 67.8% had weight control experience. The percentage of the osteoporosis, osteopenia and normal groups were 2.8%, 53.5% and 43.8%, respectively, and the percentage of the underweight, normal and overweight groups according to BMI were 27.9%, 57.2% and 14.9%, respectively. 2) The levels of stress and health promotion lifestyle were 2.9 and 2.3, respectively. 3) There was a positive correlation between BMD and BMI (r=.196, p<.01). There was a negative correlation between stress and health promotion lifestyle (r=-.35, p<.01). 4) Weight control experience made negative effects on BMD and BMI. Conclusion: The findings of this study suggest the necessity of new health promotion programs to increase bone density of female college students. Stress management programs are also needed.