• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.2
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• pp.117-126
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• 2002

Concrete containing discontinuous discrete steel fiber in a normal concrete is called steel fiber reinforced concrete(SFRC). Tensile as well as flexural strengths of concrete could be substantially increased by introducing closely spaced fibers which delay the onset of tension cracks and increase the tension strength of cracks. However, many properties of SFRC have not been investigated, especially properties on repeated loadings. Thus, the purposes of this dissertation is to study the flexural fatigue characteristics of SFRC considering cumulative damage. A series of experimental tests such as compressive strength, splitting tensile strength, flexural strength, flexural fatigue, and two steps stress level fatigue were conducted to clarify the basic properties and fatigue-related properties of SFRC. The main experimental variables were steel fiber fraction (0, 0.4, 0.7, 1, 1.5%), aspect ratio (60, 83). The principal results obtained through this study are as follows: The results of flexural fatigue tests showed that the flexural fatigue life of SFRC is approxmately 65% of ultimate strength, while that of plain is less than 58%. Especially, the behavior of flexural fatigue life shows excellent performance at 1.0% of steel-fiber volume fraction. The cumulative damage test of high-low two stress levels is within the value of 0.6 ∼ 1.1, while that of low-high stress steps is within the value of 2.4 ∼ 4.0.

• The Journal of Korean Academic Society of Nursing Education
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• v.26 no.1
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• pp.16-24
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• 2020

Purpose: This study examined the effects of guided imagery on stress, state anxiety, test anxiety and core basic nursing skill performance score of undergraduate nursing student. Methods: An equivalent control group pretest-posttest design was utilized. A total of 45 senior nursing students were randomly assigned to either an intervention group to receive guided imagery, or a control group (experimental group=23 students, control group=22 students). The guided imagery was provided via audio files to the intervention group for eight minutes, once a day for five days. The pretest was given before the intervention to measure variables for both groups, and the posttest was performed immediately afterward and three days after the intervention. Results: Significant differences were found between the two groups in stress ((F=4.94, p=.012), state anxiety (F=5.99, p=.005), and basic core nursing skill performance scores (Z=-2.45, p=.015). Conclusion: Guided imagery for nursing students has been identified as effective for stress, state anxiety, and basic core nursing skill performance scores. Guided imagery can be used as an effective intervention before performance tests. These study results can provide useful data for nursing education.

• Journal of the Korean Home Economics Association
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• v.50 no.3
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• pp.51-58
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• 2012

This study investigated the relationship between infants' temperament and mothers' parenting stress. This investigation is done by focusing on the interaction effects between the infants' temperament and maternal factors. A total of 1,120 infants and their mothers from a national sample were selected as subjects for carrying this investigation. The EAS (Emotionality, Activity and Sociality) Temperament Survey for Children: Parental Ratings was used to measure the infants' emotionality temperament, and PSI-SF(Parenting Stress Index-Short Form), KMSS(Kansas Marital Satisfaction Scale) and a survey on socio-demographic variables were used for the maternal factors. Two-way ANOVA revealed that the parenting stress was significantly different according to the infants'emotionality temperament. Most importantly, there were significant interaction effects between the infants' emotionality temperament and maternal factors(education level, employment status and marital satisfaction). The results were discussed in terms of the goodness of fit of the temperament and parenting models.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.20 no.4
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• pp.400-409
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• 2013

Purpose: This study was conducted to define factors influencing health-related quality of life (HRQOL) in women undergraduates. Independent variables of physical activity, attitude to eating, satisfaction with body shape, stress and self-esteem were used to predict HRQOL. Method: Data were analyzed using the SPSS/WIN 20.0 program for descriptive statistics, Pearson correlation coefficients and stepwise multiple regression. Participants were 245 women undergraduates who were recruited from July to September 2012. Result: The mean for the physical component summary (PCS) of HRQOL was 73.89, and for the mental component summary (MCS) was 68.45. There were significant correlations between attitude to eating, satisfaction with body shape, stress, self-esteem and the two components of HRQOL. The groups with minimal or health enhancing activity were significantly higher in PCS and MCS than the inactivity group. Stepwise multiple regression analysis indicated that 35% of the variance in PCS was significantly accounted for by self-esteem, perceived stress, attitude to eating, and physical activity, and 45% of the variance in MCS was significantly accounted for by perceived stress, self-esteem, attitude to eating, and satisfaction with body shape. Conclusion: The results indicate that these factors influencing HRQOL should be considered when developing programs to improve HRQOL for women undergraduates.

• Child Health Nursing Research
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• v.17 no.2
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• pp.69-73
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• 2011

Purpose: This study was designed to identify mother and infant related factors that influence child-care stress among the mother of newborn infants. Methods: Data were collected through self-administered questionnaires and descriptive statistics, correlation and multiple regression were used to analyze the data. The data survey was conducted with 957 conveniently selected mothers of infants when they visited a public health center in Seoul to have their children immunized. Results: The average item score for the Childcare Stress Inventory was 38.03, for the Edinburgh Postnatal Depression Scale, 9.31 and for the Degree of Bother Inventory, 23.42. The CSI was positively correlated to EPDS (r=.44, p<.001) and DBI (r=.40, p<.001). Also these two variables explained 30.0% of CSI in infants' mothers. Conclusion: These findings are expected to expand the understanding about postpartum mothers' child-care stress and can contribute to the development of comprehensive interventions based on community health nursing.

• Steel and Composite Structures
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• v.7 no.4
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• pp.303-320
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• 2007

The objective of this study is to clarify the structural features of members consisting of connection, as a series of the previous study on the CFT column-to-beam tensile connection with combined cross diaphragm. This connection has the merits that the stress is distributed evenly on the beam flange and the diaphragm and the stress concentration is reduced, by improving the stress transfer route and restraining abrupt deformation of diaphragm. The finite element analysis was performed to find out the stress transfer through sleeve which is an important member of the connection with combined cross diaphragm. The length and thickness of sleeve were used as variables for the analysis. As the analysis results, the length and thickness of sleeve didn't influence on the capacity of the connection and played a role of a medium to transfer the stress from the diaphragm to the filled concrete. It is proposed that the appropriate length of sleeve be the same value as the diameter of sleeve and the appropriate ratio of sleeve diameter to sleeve thickness be 20. Two equations for evaluation of the load-carrying capacity of the connection were also proposed through the modification of the evaluation equation suggested in the previous study.

• Computers and Concrete
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• v.24 no.5
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• pp.445-452
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• 2019

In this paper, dynamic stress, strain and deflection analysis of concrete pipes conveying nanoparticles-water under the seismic load are studied. The pipe is buried in the soil which is modeled by spring and damper elements. The Navier-Stokes equation is used for obtaining the force induced by the fluid and the mixture rule is utilized for considering the effect of nanoparticles. Based on refined two variables shear deformation theory of shells, the pipe is simulated and the equations of motion are derived based on energy method. The Galerkin and Newmark methods are utilized for calculating the dynamic stress, strain and deflection of the concrete pipe. The influences of internal fluid, nanoparticles volume percent, soil medium and damping of it as well as length to diameter ratio of the pipe are shown on the dynamic stress, strain and displacement of the pipe. The results show that with enhancing the nanoparticles volume percent, the dynamic stress, strain and deflection decrease.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.333-336
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• 2006

A new forming method for metal/ other metal two-layer tubes by multi-billet extrusion (MBE) is introduced. The forming possibilities of two-layer tubes CDA 365(inner)/Al 1100(outer) and Al 2014(inner)/Al 1100(outer) by MBE are investigated according to the given frictional condition and die profile. The results show that two-layer tube composed by two types tube as abovementioned can be manufactured by MBE. Some stated variables in the forming process such as effective stress and normalized pressure at welding surface are analyzed by FEM code ($DEFORM^{TM}$-3D)

• Journal of the Health Care and Life Science
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• v.9 no.1
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• pp.51-60
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• 2021

This study was conducted to identify the perceived stress, self-esteem and clinical practice stress of nursing students and how these variables affect clinical practice stress. Participants consisted of 164 nursing students who were in the third and fourth years who had experienced clinical practice at two nursing universtities located in Gyonganam and Jeonnam, and agreed to the survey. Data were collected using questionnaires form April 1 to April 30, 2021. Collected data were analyzed using the SPSS 22.0 Win statistics program with descriptive statistics, an t-test, ANOVA, scheffe's test, and multiple regression. The study found that clinical preactice stress was positively correlated with perceived stress but negatively correlated with self-esteem and the factors affecting clinical practice stress wre perceived stress, self-esteem, major satisfaction and interpersonal relationships and their explanatory power was 27.0%. This suggests that it is necessary to develop and apply a program to reduce perceived stress and improve self-esteem in order to reduce clinical practice stress of nursing students.

• Child Health Nursing Research
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• v.7 no.3
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• pp.359-370
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• 2001

The purpose of this study was to identify the effects of the guided imagery program on stress of adolescents. The study design was nonequivalent control group pretest-posttest study. The Data were collected from the 1st to 30th of September in 2000. Two schools were selected as an experimental group and a control group. Each group included two classes. The experimental group was consisted of 40 male students and 42 female students and the control group was consisted of 41 males and 42 females. The guided imagery was provided with audiotapes to the subjects in the classroom for 8 minutes per each therapy, 5 times a week for 4 weeks. The pretest was given before the therapy to measure variables for both groups and the posttests were performed twice after 2 weeks and 4 weeks from the start of intervention. The Instruments used in this study were perception of stress scale developed by Park(1996), Vividness of Imagery Scale; short form of bett's test scale developed by Sheenhan(1967). The data were analyzed by the SAS program using Chi-square test, t-test, repeated measure ANOVA and Bonferroni correction. The results of this study are as follows: 'The level of stress of adolescents who received the guided imagery will be significantly lower than that of control group' was supported(F=10.14, p=.00). In conclusion, the guided imagery was suggested as an effective nursing intervention did reduce the stress of adolescents which school nurses could utilize for adolescents at school.