• Safety and Health at Work
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• v.13 no.4
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• pp.415-420
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• 2022

Background: Healthcare workers perform an emotionally exhausting daily work activity, making them prone to occupational hazards, namely psychosocial ones. This study aims to assess the impact of psychosocial risk factors on healthcare workers' mental health. Methods: A cross-sectional study was developed between May and June of 2021 with 479 healthcare workers from Portuguese hospitals. The Depression, Anxiety and Stress Scale was used to assess mental health, and psychosocial risks were assessed through the Health and Work Survey - INSAT. Statistical analysis was performed to identify the psychosocial risk factors related to anxiety, depression, and stress. Subsequently, a multiple linear regression was performed to identify the models that better explained psychosocial risk factors' relationship with anxiety, depression, and stress. Results: Data showed a strong exposure to psychosocial risks. Work pace and intensity, work relationships, and emotional demands stood out with higher global average percentages for yes answers to "exposure and discomfort." The analysis of the b values and p-values from the multiple linear regression shows that some cross-sectional psychosocial risks are predictors of anxiety and stress dimensions, and other psychosocial risks differ in the two mental health dimensions. However, it is important to highlight that healthcare workers still showed great joy and pleasure in performing their work activities. Conclusion: Support network development in the work environment is needed to prevent healthcare workers' emotional stress and promote their psychological well-being. Therefore, new research is essential to understand the psychosocial risks that affect healthcare workers and assess the less visible effects of work-health relationships.

• Journal of Korean Biological Nursing Science
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• v.23 no.1
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• pp.22-30
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• 2021

Purpose: This descriptive study aimed to investigate heart rate variability (HRV) according to sex and to elucidate the influence of negative emotion such as levels of stress, anxiety and depression on HRV among Korean college students based on a neurovisceral integration model. Methods: A descriptive study design was used. Eighty-six healthy college students participated in the study. Resting HRV and standing HRV on orthostatic stimulation were measured for 5 minutes during 4-6 p.m. in the afternoon. Levels of stress, anxiety and depression were assessed using the Global assessment of recent stress, State-Trait Anxiety Inventory and Beck Depression Index, respectively. Results: Out of the 86 students, 47 (54.7%) were men and 39 (45.3%) were women. Root mean square of the differences between adjacent RR intervals (RMSSD) and normalized high frequency (nHF) on standing HRV were significantly lower in men than in women (p= .005, p= .019, respectively). Male gender (β= 0.30, p= .013), higher level of stress (β= -0.36, p= .009) and lower level of depression (β = 0.30, p= .044) exerted a significant influence on decreased nHF in the multiple regression analysis. Conclusion: We suggest that men are more vulnerable to having reduced vagal activity on HRV than women. Since male gender, higher level of stress and lower level of depression level influenced decreased vagal activity, strategies are needed to improve stress and depression rather than anxiety especially for men, which contribute to promoting HRV to prevent cardiac health diseases.

• Advances in nano research
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• v.9 no.3
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• pp.147-156
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• 2020

This research is related to nonlinear stability analysis of advanced microbeams reinforced by Graphene Platelets (GPLs) considering generic geometrical imperfections and thermal loading effect. Uniform, linear and nonlinear distributions of GPLs in transverse direction have been considered. Imperfection sensitivity of post-bucking behaviors of the microbeam to different kinds of geometric imperfections have been examined. Geometric imperfection is first considered to be identical as the first buckling mode, then a generic function is employed to consider sine-type, local-type and global-type imperfectness. Modified couple stress theory is adopted to incorporate size-dependent behaviors of the beam at micro scale. The post-buckling problem is solved analytically to derive load-amplitude curves. It is shown that post-buckling behavior of microbeam is dependent on the type geometric imperfection and its magnitude. Also, post-buckling load can be enhanced by adding more GPLs or selecting a suitable distribution for GPLs.

• Journal of Ocean Engineering and Technology
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• v.34 no.2
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• pp.120-127
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• 2020

Evaluation of fatigue strength considering the springing effect of very large container ships is crucial in the design stage. In this study, we established a fatigue strength evaluation method considering a linear springing component in the frequency domain. Based on a three-dimensional global model, a fluid-structure interaction analysis was performed and the modal superposition method was applied to determine the hot spot stress at the hatch corner of very large container ships. Fatigue damage was directly estimated using the stress transfer function with a linear springing response. Furthermore, we proposed a new methodology to apply the springing effect to fatigue damage using hull girder loads. Subsequently, we estimated the fatigue damage contribution due to linear springing components along the ship length. Finally, we discussed the practical application of the proposed methods.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1407-1412
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• 2003

In MEMS devices, packaging induced stress or stress induced structure deformation become increasing concerns since it directly affects the performance of the device. In this paper, deformation behavior of MEMS gyroscope package subjected to temparature change is investigated using high-sensitivity $Moir{\acute{e}}$ interferometry. Using the real-time $Moir{\acute{e}}$ setup, fringe patterns are recorded and analyzed at several temperatures. Temperature dependent analyses of warpages and extensions/contractions of the package are presented. Linear elastic behavior is documented in the temperature region of room temperature to $125^{\circ}C$. Analysis of the package reveals that global bending occurs due to the mismatch of thermal expansion coefficient between the chip, the molding compond and the PCB.

• Advances in aircraft and spacecraft science
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• v.1 no.2
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• pp.125-143
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• 2014

This paper provides a new technique for solving the static analysis of arbitrarily shaped composite plates by using Strong Formulation Finite Element Method (SFEM). Several papers in literature by the authors have presented the proposed technique as an extension of the classic Generalized Differential Quadrature (GDQ) procedure. The present methodology joins the high accuracy of the strong formulation with the versatility of the well-known Finite Element Method (FEM). The continuity conditions among the elements is carried out by the compatibility or continuity conditions. The mapping technique is used to transform both the governing differential equations and the compatibility conditions between two adjacent sub-domains into the regular master element in the computational space. The numerical implementation of the global algebraic system obtained by the technique at issue is easy and straightforward. The main novelty of this paper is the application of the stress and strain recovery once the displacement parameters are evaluated. Computer investigations concerning a large number of composite plates have been carried out. SFEM results are compared with those presented in literature and a perfect agreement is observed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.3
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• pp.183-190
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• 2019

This paper introduces a near-tip grid refinement and explores its usefulness in the crack analysis by the natural element method(NEM). As a sort of local h-refinement in finite element method(FEM), a NEM grid is locally refined around the crack tip showing high stress singularity. This local grid refinement is completed in two steps in which grid points are added and Delaunay triangles sharing the crack tip node are divided. A plane strain rectangular plate with symmetric edge cracks is simulated to validate the proposed local grid refinement and to examine its usefulness in the crack analysis. The crack analysis is also simulated using a uniform NEM grid for comparison. Unlike the uniform grid, the refined grid provides near-tip stress distributions similar to the analytic solutions and the fine grid. In addition, the refined grid shows higher convergence than the uniform grid, the global relative error to the total number of grid points.

• Korean Journal of Culture and Social Issue
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• v.28 no.1
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• pp.43-59
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• 2022

This study conducted a multiple mediation analysis using sub-factors of basic psychological needs (BPNs) as mediators in the relationship between problem gambling and stress of gambling addicts to confirm that BPNs and stress, which affect gambling addiction, may be the result of problem gambling and to find effective intervention strategies. A total of 206 adults gambling addicts were screened by using CPGI. Descriptive statistics, correlation, hierarchical regression, and mediation analysis were conducted. Hierarchical regression analysis results yielded that problem gambling and sub-factors of BPNs were significant predictors of stress when controlling for gender and debt. The sub-factors of BPNs mediated the relationship between problem gambling and stress. These results indicated that BPNs and stress are not only the causes of gambling addiction but also the results from the harmful consequences of gambling addiction. The study supported the possibility of the psychological process of "Deficits of BPNs (of gambling users) → stress (of gambling users) → problem gambling → gambling addiction (of gambling addicts) → problem gambling → Deficits of BPNs (of gambling addicts) → stress (of gambling addicts)" among the variables and provided clinical implications for problem gambling counseling. Lastly, the limitations of this study and suggestions for further study were discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.2
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• pp.112-119
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• 2018

Heat stress during the ripening stage reduces the yield and quality of rice. Considering the adverse effects of global warming, it is necessary to breed heat stress tolerant rice cultivars and analyze their stress tolerance characteristics. We investigated the ripening characteristics and antioxidant enzyme activity of Ilmi under heat stress condition during the ripening stage. Ripening rate, 1000 brown grain weight, and rice quality of Ilmi were not significantly changed by heat stress during the ripening stage. Leaf chlorophyll, chlorophyll a/b ratio, and malondialdehyde (MDA) contents of Ilmi leaves were also less changed than those of Ilpum. These results strongly suggested that Ilmi has heat tolerance characteristics during the ripening stage. Analysis of antioxidant enzyme activity of Ilmi revealed that peroxidase (POX) activity was significantly higher than that of Ilpum, and showed a significant correlation with the change in chlorophyll a/b ratio and hydrogen peroxide content of flag leaves of Ilmi. These data suggest that the high POX enzyme activity of Ilmi could be considered one of its major heat tolerance characteristics.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.429-438
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• 2024

This study was conducted to investigate the factors affecting stress before clinical practice among nursing students. The subjects of the study were surveyed on third-grade students who were about to undergo their first clinical practice. The data collection period was from December 22, 2023 to January 10, 2024, with a total of 191 nursing students. The instruments used for this study were Perceived stress scale(Pss), Self-leadership, and Global Interpersonal Communication Competency(GICC) scale. The data were analyzed by t-tests, ANOVA, Scheffé test, Pearson correlation coefficient, and multiple regression using SPSS/WIN 21.0. The results of the study showed a negative correlation with self-leadership(r=-.29, p=<.001) and interpersonal communication competence(r=-.40, p=<.001). In the stepwise multiple regression analysis, it was found that the stress levels of nursing students before clinical practice were influenced by factors such as gender, satisfaction with the department, and interpersonal communication competence. These variables explained 33.7% of the variance in pre-clinical stress. Based on the findings of this study, it is recommended to develop educational interventions that can help reduce stress before clinical practice among nursing students.