• Geomechanics and Engineering
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• v.9 no.5
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• pp.645-667
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• 2015

Single treatment and staged treatments in vertical wells are widely applied in sandstone and mudstone thin interbedded (SMTI) reservoir to stimulate the reservoir. The keys and difficulties of stimulating this category of formations are to avoid hydraulic fracture propagating through the interface between shale and sand as well as control the fracture height. In this paper, the cohesive zone method was utilized to build the 3-dimensional fracture dynamic propagation model in shale and sand interbedded formation based on the cohesive damage element. Staged treatments and single treatment were simulated by single fracture propagation model and double fractures propagation model respectively. Study on the changes of fracture vicinity stress field during propagation is to compare and analyze the parameters which influence the interfacial induced stresses between two different fracturing methods. As a result, we can prejudge how difficult it is that the fracture propagates along its height direction. The induced stress increases as the pumping rate increasing and it changes as a parabolic function of the fluid viscosity. The optimized pump rate is $4.8m^3/min$ and fluid viscosity is $0.1Pa{\cdot}s$ to avoid the over extending of hydraulic fracture in height direction. The simulation outcomes were applied in the field to optimize the treatment parameters and the staged treatments was suggested to get a better production than single treatment.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.731-740
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• 2008

This paper deals with the fatigue behavior and strength of a new-type of steel-concrete composite bridge deck. The new-type composite bridge deck consists of corrugated steel plate, welded T-beams, stud-type shear connectors and reinforced concrete filler. A total of eight composite bridge deck specimens were fabricated, the fatigue tests were conducted under four-point bending test with three different stress ranges in constant amplitude. According to the test results, the fatigue crack generated at the welding part of the corrugated steel plate, progressed down to the bottom of the steel plate and encountered the crack, which came out from the opposite side at the same position. After the two cracks were connected at the bottom of the steel plate, the lower flange was cut off and the fatigue crack developed up to the T-beam. And the displacements and strains of fatigue test specimens were increasing with cyclic loading number, these were changed sharply at the fatigue failure. The fatigue results are compared with the design S-N curves specified in the Korea Highway Bridge Design Specifications and data in NCHRP 102 and NCHRP 147 report. The new-type composite bridge deck has a stress category of C, which means that new-type composite bridge deck can be designed by the current fatigue design specifications provided for steel members.

• Journal of the Korean Society of School Health
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• v.11 no.1
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• pp.63-74
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• 1998

The purposes of this study are to show in interpersonal relations what factors male students are stressed from, how they experience stress, how they cope With it in each situation, and what this results in It attempt to gam basic materials to promote male student health and positive coping methods, The subject of this study was 15 male students of C University located in Seoul and Kyeonggui-Do They were composed of 5 sophomores, 5 Juniors and 5 seniors The period for collecting materials was October 1997 to January 1998, and the interview time ranged from 50 minutes to two hours The interview frequency was one to three times as occasion demanded, The materials were analyzed by the methods and theory suggested by Strauss & Corbin (1990) The results were 130 categories grouped into 33 divisions by similarity Finally, they were united into 9 higher categories In interpersonal relations the core category of male student stress is "affliction", and it follows the course of generation-coping-resolution The types showed in the course of material analysis are as follows, (1) When the subject student is on good terms with the other and the stress is repeated- "affliction" is strong and continuous-and his ability sense is strong, he copes with "affliction" With his own will and solves It affirmatively, (2) When the subject student is on good terms with the other and the stress is repeated-so "affliction" is strong and continuous-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively (3) When the subject student is on good terms with the other and the stress is temporary-"affliction" is strong and temporary-and his ability sense is strong, he copes with "affliction" with his own will and solves it affirmatively (4) When the subject student becomes estranged from the other and the stress is temporary-"affliction" is weak and temporary-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively, (5) When the subject student becomes estranged from the other and the stress is repeated-"affliction" is strong-and continuous and his ability sense is strong, he copes with "affliction" with his own will and solves it affirmatively (6) When the subject student becomes estranged from the other and the stress is repeated-"affliction" is strong and continuous-and his ability sense is weak, he copes with "affliction" with an emotional bias and solves it negatively. According to the above results, the conditions of cause and effect for male students to generate "affliction" should be understood in order to help cope with stress caused by interpersonal relations A program for education and counseling should be developed for male students to strengthen their 'ability sense' in choosing coping strategies In addition, the individual estimation for ability sense should be performed when education and counseling them.

• The Korean Journal of Food And Nutrition
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• v.30 no.1
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• pp.83-95
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• 2017

This study examined the socioeconomic factors that affect self-rated health (SRH) in healthy adults, and the relationship of SRH to health-related habits, serum biochemical indices, and nutritional intakes. Subjects consisted of 1,154 healthy adults without any known disease, aged 19 to 65 years (average age of 36.7), whose information was obtained from the 2013 Korean National Health and Nutritional Examination Survey data. Of these subjects, 73 rated themselves as 'very healthy,' 460 indicated that they were 'healthy,' 568 self-identified as 'ordinary', and 53 put themselves in the 'unhealthy' category. The proportion of subjects who chose 'unhealthy' was significantly increased with higher frequencies of disruptions in their daily lives (p<0.05), regret after drinking (p<0.05), smoking (p<0.001), and higher levels of stress (p<0.001). On the other hand, the proportion of subjects reported as 'very healthy' was significantly higher with regular intense (p<0.001) or moderate physical activities (p<0.05), regular walking (p<0.05), a perception of being 'normal' in their body image (p<0.01), a decrease of body weight more than 3 kg in the past year (p<0.05), and without risk factors for metabolic syndrome (p<0.05). Serum triglyceride level was lower, and 25-(OH) vitamin D content was significantly higher, in the 'very healthy' group as compared to the 'unhealthy' group (p<0.05). Dietary fiber and vitamin C intakes were significantly higher in the 'very healthy' group than 'unhealthy' group (p<0.05). The overall results suggest that a healthy lifestyle, including regular exercise, non-smoking, good stress management, and higher intakes of fiber and vitamin C, may be potential factors that affect one's positive perception of health.

• Korean Journal of Social Welfare
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• v.69 no.2
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• pp.219-246
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• 2017

The purpose of this study is to develop a substantive theory that understand the burnout and secondary traumatic stress experience of social workers who worked in the trauma centers. This research was conducted by Grounded Theory. The result is as follow: In the initial coding, 159 units of mean, 47 subcategories, and 12 main categories. The central phenomenon of the initial coding was 'the wounded existence.' In the focused coding, the core category was 'seeking to recover professional identity as a social worker.' In the theoretical coding, the burnout and secondary traumatic stress experience of social workers who worked in the trauma centers were classified as four phases;'Commitment to the mission', 'Conflict', 'Stagnant' and 'Disruption'. Based on the findings, the preparation for the disaster social work practice, the perspective on "social healing" of trauma, and the necessity of the mandatory policy or intervention for social workers self-care were discussed.

• Journal of Industrial Convergence
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• v.21 no.3
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• pp.117-127
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• 2023

The study is a qualitative study to understand the stress experience of pregnant women by exploring the vivid experiences of pregnant women during the COVID-19 pandemic through a phenomenological approach. As for the study subjects, 12 pregnant women who were pregnant during the COVID-19 pandemic were selected as subjects and in-depth interviews were conducted. Interviews with participants were conducted from June to October 2022, and data were analyzed through the Taguette program using the Colaizzi (1978) analysis method. As a result of the analysis, the category of experience was derived as 4 themes and 12 sub-topics. The main themes appeared as confusion due to inaccurate information, collapsed prenatal care, stress due to a controlled life, and body and mind adapting. It was confirmed that social support for the health of pregnant women and the establishment of a stable medical system need to be done overall. Further studies are needed to support this.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.70-75
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• 2002

This paper proposes new single stage power factor correction (PFC) full bridge converter. The proposed converter is combined previous ZVS full bridge DC/DC converter with two inductors, two diodes, two magnetic coupling transformer for PFC. This process of power is isolated from the source and also regulate stable DC output voltage in a category. In this topology, the voltage stress of main switches is reduced by zero voltage switching. Moreover, the proposed converter doesn't need active PFC switch and auxiliarly circuits, like control and gating board, so it could decrease the size and cost and increase the efficiency.

• Journal of Oriental Neuropsychiatry
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• v.17 no.2
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• pp.199-207
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• 2006

Pain disorder is a category of somatoform disorder that be diagnosed when the pain is starting and getting worse associated with psychological factors. At the recent study, it revealed that stress might be more strong factor in occurring and sustaining the somatoform disorder. In this case, a 42 years old female patient had a chronic pain disorder 3 years ago, suddenly complained of an eyeball pain due to retina rupture induced by severe stress. In the view of oriental medicine, pain disorder belongs to GuQiJakTongJung. So, we diagnosed her state as GuQiJakTongJung and treated her such as herbal medicine, acupuncture and phlebotomy therapy. In result, the chronic pain of the patient was improved, and also general condition was getting better.

• Wind and Structures
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• v.19 no.5
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• pp.523-540
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• 2014

This paper presents a comprehensive study of pressure developed on different faces of a 'Y' plan shape tall building using both numerical and experimental means. The experiment has been conducted in boundary layer wind tunnel located at Indian Institute of Technology Roorkee, India for flow condition corresponding to terrain category II of IS:875 (Part 3) - 1987, at a mean wind velocity of 10 m/s. Numerical study has been carried out under similar condition using computational fluid dynamics (CFD) package of ANSYS, namely ANSYS CFX. Two turbulence models, viz., $k-{\varepsilon}$ and Shear Stress Transport (SST) have been used. Good conformity among the numerical and experimental results have been observed with SST model yielding results of higher magnitude. Peculiar pressure distribution on certain faces has been observed due to interference effect. Furthermore, flow pattern around the model has also been studied to explain the phenomenon occurring around the model.

• Structural Engineering and Mechanics
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• v.81 no.3
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• pp.379-394
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• 2022

Shallow footings usually belonged to the category of thick plate structures. For accurate analysis of thick plates, the contribution of out-of-plane components of the stress tensor should be considered in the formulation. Most of the available shallow footing models are based on the classical plate theories, which usually neglect the effects of the out-of-plane stresses. In this study, a mixed-field plate finite element model (FEM) is developed for the analysis of shallow footings rested on soil foundations. In addition to displacement field variables, the out-of-plane components of the stress tensor are also assumed as a priori unknown variables. For modeling the interaction effect of the soil under and outside of the shallow footings, the modified Vlasov theory is used. The tensionless nature of the supporting soil foundation is taken into account by adopting an incremental, iterative procedure. The equality requirement of displacements at the interface between the shallow footing and soil is fulfilled using the penalty approach. For validation of the present mixed FEM, the obtained results are compared with the results of 3D FEM and previous results published in the literature. The comparisons show the present mixed FEM is an efficient and accurate tool for solving the problems of shallow footings rested on subsoil.