• Tribology and Lubricants
• /
• v.31 no.5
• /
• pp.189-194
• /
• 2015

This paper focuses on the conformal contact problem. A typical example of conformal contact is the contact between a pin and hole. In particular, this paper focuses on the condition for assuming a contact stress field to be a Hertzian pressure profile by using well-known classical solutions associated with Hertzian contact. Persson first developed the conformal contact analysis method around half a century ago, but there have been no significant improvements since then. The present research also adopted this method, but developed new solutions from the viewpoint of application to structural design. The analysis began with a comparison between Persson°Øs conformal contact stress and the Hertzian stress fields. The next step was to check the differences in the normalized stress values of both. This study used the tolerance for the difference in the peak stresses of Persson°Øs solution and the Hertz solution to validate the Hertzian assumption. This gave the range for the difference in radii of the pin and hole when the contact force and mechanical properties of the material are specified. The results showed that, at a tolerance of 5%, the Hertzian assumption is valid if half of the contact angle is less than 35°ý. In addition, the Hertzian assumption holds even for a relatively long contact length, in contrast to the general incomplete contact problem. This paper discusses these results along with other aspects of the application to the design.

• Korean Journal of Health Education and Promotion
• /
• v.22 no.4
• /
• pp.123-136
• /
• 2005

Purpose: This study was to investigate the gender difference of relationship between psycho-social factors ana smoking, drinking in adolescents. Method: The stratified cluster sample consisted of 925 adolescents. Data were collected from May to March 2002. The instruments used in this study were Perceived Stress, DES-D, Social Support and Self-Esteem. Results: The results showed that female had more perceived stress, depressed than male. Male had more social support network, smoke than female. Male who smoked cigarettes were more perceived stress, depressed than those who did not smoke. Female who smoked cigarettes were more social support network, and had less self-esteem than those who did not smoke. Also male who drank alcohol were more perceived stress, depressed than those who did not drank. Female who drank alcohol were perceived stress, depressed, social support network, and had less self-esteem than those who did not drank. Conclusion: It is hoped that much more research on gender difference in adolescents who smoked cigarettes, drank alcohol will be implemented in the future. In addition, it is suggested the application of various interventions to deal with drinking and smoking behavior among female and male adolescents.

• Journal of Korean Association for Spatial Structures
• /
• v.20 no.3
• /
• pp.91-98
• /
• 2020

For form stability of membrane structures, membrane material is required to be in tension. Therefore, in planning and maintenance management, the engineer should consider enough about introduction of stress during construction and re-introduction of stress after completion. Clamping part is an important portion with the function for introducing tension into membrane materials, and the function to transmit stress to boundary structures, such as steel frames. Then, the purpose of this research is to clarify stress condition and stress transfer mechanism including clamping part of membrane structures, and to grasp the changing tendency of membrane structures with the passage of time. In this research, following previous one, we perform well-balanced evaluation by conducting tensile fractured tests of clamping part's specimens, and by measuring individually the amount of displacement of not only overall specimen's length but membrane material and clamping part. Thereby, we consider the influence the difference in the hardness of edge rope and the difference in the direction of thread affect modification and fracture load.

• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.186-191
• /
• 2001

Tensile residual stress happen by difference of coefficients of thermal expansion between fiber and matrix is one of the serious problems in metal matrix composite(MMC). In this study, TiNi alloy fiber was used to solve the problem of the tensile residual stress as the reinforced material. TiNi alloy fiber improves the tensile strength of composite by occurring compressive residual stress in matrix using shape memory effect of it. Pre-strain was added to generate compressive residual stress inside TiNi/A16061 shape memory alloy(SMA) composite. It was also evaluated the effect of compressive residual stress corresponding to pre-strains variation and volume fraction of TiNi alloy. AE technique was used to clarify the microscopic damage behavior at high temperature and the effect of pre-strain difference of TiNi/A16061 SMA composite. In addition, two dimensional AE source location technique was applied to inspect the crack initiation and propagation in composite.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.18 no.1
• /
• pp.131-140
• /
• 2012

Purpose: The purpose of this study was to investigate the degrees of and relationships between self-leadership, stress of clinical practice and self-disclosure in a group of college female students. Methods: Data were collected from 258 participants with self-report questionnaires in August, 2011. Results: There were significant differences in the level of 'self-leadership' depending on 'interpersonal relationships', 'application motivation', 'satisfaction with nursing as a major' and 'satisfaction in clinical practice'. And also there was significant difference in the level of 'self-disclosure' depending on 'interpersonal relationships'. But there was no significant difference in the level of 'stress of clinical practice' depending on general characteristics of participants. There were significant correlations between 'self-leadership' and self-disclosure, 'stress of clinical practice' and 'self-disclosure'. Conclusion: The results of this study suggest that it is needed to develop diverse programs that can reduce the stress of clinical practice by strengthening the capacity of self-leadership and self-disclosure.

• Korean Journal of Adult Nursing
• /
• v.14 no.4
• /
• pp.581-590
• /
• 2002

Purpose: The purpose of this correlational study was to identify relationships among job stress, health beliefs and health behaviors of aircrews and contributing factors to aircrew's health promoting behaviors. Method: Two-hundred twenty-four aircrew members completed questionnaires. The questionnaires were composed of a demographic form, health behavior scale, self-efficacy scale, perceived benefit scale, perceived barrier scale, job demand scale, and latitude scale. Result: The subject's health behavior has shown significant correlations with self-efficacy, benefit, and barrier. Significant negative correlations were found between job stress and self-efficacy. Relationships between job stress and barriers were also statistically significant. In demographic features, statistically significant difference were found between subject's rank and job stress score. Also, there was a significant difference between health behavior and the subject's age. Conclusion: Future efforts should focus on the development of a program to consider aircrew's perceived benefits, perceived barriers and self-efficacy to the compliance of health promoting behaviors.

• Journal of Korean Academy of Nursing
• /
• v.41 no.1
• /
• pp.26-35
• /
• 2011

Purpose: This study was done to compare the effects of abdominal aroma massage and meridian massage on constipation and stress in college women with functional constipation. Methods: The participants were 38 college women, 18 were in the aroma group and 20 in the meridian group. The aroma massage was given using aroma oil which was a mixture of lemon, lavender, rosemary, and cyprus. The meridian massage was given at 9 accupoints which influence intestinal functions. The treatment was given 5 days a week for 4 weeks. A constipation severity score, weekly defecation frequency, and a stress response score were measured before and every week of 4 weeks of the experiment. Results: While there was no significant difference between two groups, there was a significant difference within the groups in the constipation severity (aroma group: 1st week, meridian group: except 4th week), defecation frequency (aroma group: 3rd week, meridian group: 2nd and 3rd week), and stress (aroma group: all weeks, meridian group: except 4th week) after different duration of experiment. Conclusion: Based on these results, both abdominal massages relieved constipation and stress. Resorting to either types of massage will contribute to the reduction of use of stool softeners, suppositories, or enemas.

• Proceedings of the KSME Conference
• /
• 2001.06a
• /
• pp.72-77
• /
• 2001

Tensile residual stress happen by difference of coefficients of thermal expansion between fiber and matrix is one of the serious problems in metal matrix composite(MMC). In this study, TiNi fiber was used to solve the tensile residual stress as the reinforced material. TiNi fiber improves the tensile strength of composite by occurring compressive residual stress in matrix using shape memory effect of it. Pre-strain was added to generate compressive residual stress inside TiNi/A16061 composite. It was also evaluated the effect of compressive residual stress corresponding to pre-strains variation. AE technique was used to clarify the microscopic damage behavior at high temperature and the effect of pre-strain difference of TiNi/A16061 shape memory alloy composite.

• Journal of muscle and joint health
• /
• v.25 no.2
• /
• pp.75-83
• /
• 2018

Purpose: The purpose of this study is to investigate the effects of an 8-week aquatic exercise program on risk factors of metabolic syndrome and stress in women. Methods: This study employed a non-equivalent control group pretest-posttest design. A total of 35 patients were recruited through a community health center. The data were analyzed with the SPSS 22.0 version program, and the outcome variables were risk factors of metabolic syndrome including abdominal circumference, triglyceride, high density lipoprotein cholesterol, blood pressure, fasting blood glucose, and the level of stress. Results: There was no statistically significant differences in abdominal circumference, triglyceride, high density lipoprotein cholesterol, and blood pressure difference (post-pre) between the experimental and control group. However, there was a significant difference in the stress level. Conclusion: This study result support the beneficial effect of stress management in women on risk reduction for metabolic syndrome. Health professionals consider to develop strategy of the aquatic exercise program to reduce factors of metabolic syndrome.

• Transactions of Materials Processing
• /
• v.13 no.6 s.70
• /
• pp.497-502
• /
• 2004

The shape of cold rolled steel sheets is defined as the degree of flatness, and the flatter, the better. Because undesirable strip shapes of cold rolled steel sheets can affect not only visible problem but also automatic working process in customer's lines, the requirement of the customers is more and more stringent. So we usually used the tension leveler to make high quality of strip flatness. For the improvement of the quality of strip flatness, this report developed three- dimensional FEM (Finite Element Method) simulation model, and analysis about the strain and stress distribution of strip in the tension leveling process. The numerical study can be summarized as follows. (1) If we pass the edge wave material (steepness: $1.0\%$) that the stress-difference between the strip center and the edge is 5.2kgf through tension leveler. the stress-difference is decreased 0.45kgf and the steepness is improved to $0.29\%$. (2) If the Intermesh is increased from 6mm to 7mm, the steepness is improved from $0.294\%$ to $0.268\%$. (3) If the initial steepness is decreased form $1.0\%$ to $0.75\%$, the final steepness is improved from $0.294\%$ to $0.263\%$. We know that more increased intermesh and lower initial steepness make the final steepness improved.