• Proceedings of the KSME Conference
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.560-565
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• 2001

The objective of the present study is to investigate the characteristics for flow and wall shear stress in the aneurysm which is a local dilatation of the blood vessel. The numerical simulation using the commercial software for the laminar and steady flow were carried out over the diameter ratios(ratio of maximum diameter of aneurysm to the diameter of blood vessel) ranging from 1.5 to 2.5 and Reynolds number ranging from 900 to 1800. It was shown that a recirculating vortex occupied the entire bulge with its core located closer to the distal end of the bulge and the strength of vortex increased with increase of the Reynolds number and diameter ratio. Especially, for the Reynolds number of 1800 and diameter ratio of 2.5, the very weak secondary recirculating flow was produced at the left upper of the aneurysm. The position of a maximum wall shear stress was the distal end of the aneurysm(z=18mm) regardless of the Reynolds number and diameter ratios. But the maximum values of the wall shear stress increased in proportion to the increase of Reynolds number and diameter ratio.

• Korean Journal of Adult Nursing
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• 제24권1호
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• pp.38-51
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• 2012

Purpose: In this study the literature of compassion fatigue in nurses was reviewed in order to analyze the trends of overall research for level of fatigue, symptoms, and factors. Methods: For this study, five databases were searched using the key words 'compassion fatigue', 'secondary traumatization', 'secondary traumatic stress', and 'vicarious traumatization'. Thirty-six papers were analyzed. Results: Most of the compassion fatigue research (86%) was conducted between 2006 and 2011 and the most frequent research approach was quantitative research with the ProQOL which was the most frequently used instrument in the studies. He research was conducted in pediatric, emergency & trauma, oncology, psychiatric, and hospice units with no consistent patterns of t compassion fatigue levels. Factors affecting compassion fatigue were personal factors such as age, education background, work-related factors such as caring for trauma patients, work hours, psychological factors such as work stress, burnout, and support/coping factors such as organizational support, and coping resources. Conclusion: Nurses' compassion fatigue varied from low to high by nursing specialties. Many factors affected the compassion fatigue of nurses. In the future there is a need for study on Korean nurses, and identification of groups at risk for compassion fatigue. Furthermore there is a need to develop management programs on compassion fatigue in nurses, stress reduction and wellbeing.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 한국전산구조공학회 1996년도 봄 학술발표회 논문집
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• pp.27-39
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• 1996

A finite element analysis of a trunnion pipe anchor is presented. The structure is analyzed for the case of internal pressure and moment loadings. The stress results are categorized as average and linearly varying(through the thickness) stresses. The resulting stresses are interpreted per Section 111 of the ASME Boiler and Pressure Vessel Code from which the Primary(B$_1$) and Secondary(C$_1$) stress indices for pressure, the Primary(B$_2$) and Secondary(C$_2$) stress indices for moment are developed. Several analysis were peformed on various structural geometries in order to determine empirical relationships for the stress indices as a function of dimensionless ratios.

• Journal of the Korean Geotechnical Society
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• 제29권11호
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• pp.61-72
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• 2013

The consolidation tests are conducted to investigate the soil particle crushing stress for understanding the secondary compression characteristics of carbonate sandy sabkha soil caused by particle crushing under a high confining stress. The rate of secondary crushing compression ($C_{{\alpha}{\epsilon}}{^*}$) is introduced instead of the rate of secondary compression to define the characteristic of the particle crushing compression settlement ($S_s{^*}$). Void ratio ($e_p{^*}$) and settlement ($H_p{^*}$) in particle crushing are used as a reference point of secondary behavior, and the ratio of primary compression index ($C_c$) to secondary crushing compression ($C_{{\alpha}{\epsilon}}{^*}$), $C_{{\alpha}{\epsilon}}{^*}/C_c$ value was changed from 0.0105 to 0.0187. When comparing with quartz sands, secondary compression settlement of sabkha is very large due to particle crushing which is not usually observed in quartz sand. It is observed that as the depth of sabkha layer becomes deep, the $S_s{^*}$ and $C_{{\alpha}{\epsilon}}{^*}$ increase under the same stress level.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제26권5B호
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• pp.469-479
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• 2006

In order to investigate characteristics of the primary flow and the secondary currents in meandering channels, the laboratory experiments were conducted in S-curved channels with angle of bend, $150^{\circ}$, and sinuosity of 1.52. The experimental conditions was decided varying average depth and velocity. Under these experimental conditions, spatial variations of the secondary currents in multiple bends were observed. The experimental results revealed that the distribution of primary flow in straight section is symmetric without respect to the experimental condition and the maximum velocity line of the primary flow occurs along the shortest path in experimental channel, supporting the result of previous works. The secondary currents in second bend became more developed than those in first bend. Particularly, the outer bank cell developed distinctively and the secondary current intensity was low at the straight section and high at the bends, periodically. Also, the secondary current intensity at the bends was as twice to three times as that at the straight section, and has its maximum value at the second bend. The turbulent flow characteristics of meandering channel was investigated with turbulent intensity of the primary flow and Reynolds shear stress. It was observed that the turbulent intensity is increasing when the velocity deviation of the primary flow is large whereas Reynolds shear stress increases when both the velocity deviation of the primary flow and the secondary current are large.

• Applied Chemistry for Engineering
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• 제28권3호
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• pp.306-312
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• 2017

Changes in the cell growth and lipid accumulation of marine microalga Dunaliella tertiolecta were investigated in response to the combination of different stress factors including the variation of iron supply as a primary stress factor and different options in light irradiation and $CO_2$ supply as a secondary stress factor. High or limited Fe conditions could act as a stress for lipid synthesis. As a secondary stress factor, non-$CO_2$ condition was good for lipid accumulation, but the overall cell growth was sacrificed significantly after a long-time cultivation. Dark condition as a secondary stress factor also favored lipid accumulation and the extent of cell density reduction at the early period in the dark was small compared to other stress conditions. The two-stage cultivation strategy was necessary to maximize lipid production because tendencies of the cell growth and lipid content were not identical under the chosen stress condition. The first stage was for preparing a high cell density under the normal growth-favoring condition and the second stage was the stress condition to induce lipid accumulation in a short time. The short-term (12 h) incubation under the 5X Fe (3.25 mg/L) and dark conditions resulted in the best lipid productivity of 1.44 g/L/d providing 2 g/L inoculum at the second stage.

• Journal of Korean Academy of Nursing
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• 제25권1호
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• pp.141-155
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• 1995

The objective of this study was to develop a scale to measure stress in infertile couples and to test its reliability and validity. Prior to item generation, a basic decision was made to conceptualize stress in infertile couples as including two dimensions and four subdimensions. The dimensions were, intrapersonal stress including cognitive and affective stress, and interpersonal stress including marital and social stress. Initially 95 items were generated from the inter-view data of 31 primary or secondary infertile women and from a literature review. These items were analyzed through the Index of Content Validity(CVI) and 69 items were selected which met 70% or more of the CVI. This preliminary Infertility Stress Scale were analyzed for reliability and construct validity. Item analysis and factor analysis were applied for construct validity. Forty items were selected through item analysis. This procedure was based on the inter-item correlation matrix, a corrected average inter-item correlation coefficient(.30~.70), a corrected item to total correlation coefficient (.03 or more) and information about the alpha estimate if this item was dropped from the scale. The result of the initial factor analysis including varimax rotation produced eight factors. Five items deleted because of factor complexity(indiscriminate factor loadings). The secondary factor analysis including varimax rotation produced seven factors that coincided with the conceptual framework posed for the scale developed. The seven factors were labeled as ‘meaning of children’,‘worthiness’,‘tenacious linking’,‘marital satisfaction’,‘sexual satisfaction’,‘familial adjustment’ and ‘social adjustment’. The alpha coefficient relating to internal consistency was .93 for reliability The results of this study suggest that the measurement derived from the Infertility Stress Scale is useful in assessing the stress of infertile couples.

• Journal of Korean Biological Nursing Science
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• 제24권2호
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• pp.131-139
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• 2022

Purpose: This study aimed to examine the changes in stress, occupational stress, and subjective health problems of novice female nurses within the first 18 months of work. Methods: This was a longitudinal study conducted with a secondary data analysis based on the Shift Work Nurse's Health and Turnover (SWNHT) study. The participants were 178 female novice nurses who participated in all 3 data collection activities (on the first day of orientation before ward placement [T0], 6 months after work [T1], and 18 months after work [T2]). The stress, occupational stress, 8 subjective health problems (upper musculoskeletal pain, leg/foot discomfort, depression, anxiety or emotional disorder, sleep disturbance, headache, gastrointestinal disorder, menstrual disorder, and others), and the greatest health problem during the study period were measured, respectively. Data were analyzed using SPSS 26.0 to obtain descriptive statistics. Results: The subjective health of novice female nurses were found to be poor at T1 compared to T0 on both physical (upper musculoskeletal pain, leg/foot discomfort, and sleep disturbance) and psychological health problems (depression and stress). However, the psychological health problems of the participants were alleviated at T2 whereas; physical health problems persisted until T2. Conclusion: Novice nurses had poor health problems 6 months after work. Sleep disturbance and musculoskeletal pain persisted although other health problems such as depression and stress were alleviated over the period. Strategies to prevent and manage different health problems of novice female nurses at different work duration are urgently needed.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제26권6B호
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• pp.573-581
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• 2006

This paper presents a turbulence modeling of the open-channel flows over smooth-rough bed strips. A Reynolds stress model is used for the turbulence closure. The simulated mean flow and turbulence structures are compared with the previously reported experimental data. Comparisons reveal that the developed Reynolds stress model successfully predicts the mean flow and turbulence structures of open-channel flows over smooth-rough bed strips. The computed flow vectors show cellular secondary currents, of which the upflow occurs over the smooth bed strip and the downflow over the rough bed strip. It is found that the cellular secondary currents affect the mean flow and turbulence structure. A budget analysis of the streamwise vorticity equation is also carried out to investigate the mechanism by which the secondary currents are generated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1402-1405
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• 2005

This paper describes the result of structure analysis of secondary bogie frame. The purpose of the analysis is to evaluate an safety which secondary bogie frame shall be considered fully sufficient rigidity so as to satisfy proper system function under maximum load. Secondary bogie system consist of bogie frame, suspensions, wheel-sets, and brake system. Among these component, the bogie frame is most significant component subjected to the vehicle and passenger loads. The evaluation method is used the JIS E 4207 specification throughout the FEM analysis. The analysis results have been very safety and stable for design load conditions.