• Korean Journal of Occupational Health Nursing
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• v.21 no.1
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• pp.27-36
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• 2012

Purpose: The purpose of this study was to identify the trends of nurses' stress based on the last 10 years of international research and to suggest directions for future research. Methods: Fifty three articles between 2002 and 2011 were selected using key words such as 'nurse' and 'stress' from the PubMed and CINAHL. Results: The number of experimental studies increased. The nurses from the various fields were studied. Most studies used a reliable and valid tool for measuring stress of specific nursing staff. The Internet survey was recently used for a data collection method. Significant variables correlated with nurses' stress were categorized into 8 domains: Individual susceptibility, quantitative workload, qualitative workload, physical environment, organizational factors, and interpersonal conflict. Conclusion: In Korea, the next phase of research on nurses' stress needs to consider the experimental study design to find more specific causal relationships. Also, it is necessary to develop the nurses' stress tool for reliable and valid measurement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.415-424
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• 2014

The carrying capacity of existing concrete structures is evaluated by the measured data from displacement and strain gauges for given loads and the results of numerical analysis that are compared with the measured ones. Consequently, this process could be accomplished in doing the direct measurement of residual stress on existing concrete. This study is concerned with the development of IITC (Instrumented Indentation Technique for Concrete) system which is based on the experimental stress analysis technique using non-destructive test method to evaluate the residual stress of concrete structures depending on the types of applied loadings in analysing indentation load - indentation depth curve derived experimentally on concrete surface. As a result, in this paper, almost all of systematized H/W and S/W were newly developed to estimate the residual stresses of concrete structures. Thus, the creation of new experimental equations for deriving residual stresses and automatical calculations of residual stresses using the empirical formula can lead to evaluate the structural resistances conveniently in the structures from construction phase to maintenance stage.

• Journal of Ocean Engineering and Technology
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• v.2 no.2
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• pp.96-103
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• 1988

The stress distribution in the vicinity of the crack tip in the fracture mechanics is ordenarily indicated by the stress intensity factor. In the analysis of stress intensity factors, there are many theoretical and experimental methods. The stress analysis in photoelastic technique is usually made by using the difference of the principal stress of isochromatic fringe patterns. In this paper, the teflon molding technique is adopted to make a test specimen with a circular arc-crack, and that upgraded the accuracy of experiment. As the result, the experimental values of the stress intensity factors for the circular disk with a straight crack are coincided with the theoretical values. But, there is quite a difference between this expermental results on the finite plate for circular arc-crack and its theoretical values on the infinite one. Therefore, a boundary condition with regard to the loading condition on finite disk must be considered.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.10
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• pp.568-572
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• 2013

The main components, such as a reactor vessel, in commercial nuclear power plants have been welded to pipes with dissimilar metal in which Primary Water Corrosion Cracking (PWSCC) has been occurred. PWSCC has become a worldwide issue recently. This paper addresses the results of experimental and numerical analysis to prevent PWSCC by changing the stress profile that is tensile stress to compressive stress at interesting regions with plastic deformation generated by mechanical pressure. Based on the results of experimental and numerical analysis with a 6 inch pipe and dissimilar metal welded pipes, compressive stress 68~206 Mpa is generated at all locations of inner surface in the heat affected zone.

• Computers and Concrete
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• v.31 no.1
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• pp.9-21
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• 2023

The published studies usually used analytical method, numerical methods or experimental method to determine the stress-strain state and displacement of the single-layer or multi-layer curved shell types, but with a small scale model. However, a full scale multi-layer doubly curved concrete shell roof model should be researched. This paper presents the results of the experiment and simulation analysis involving stress-strain state, sliding between layers, the formation and development of the full scale double-layer doubly curved concrete shell roof when this shell begins to crack. The results of the this study have constructed the load-sliding strain relationship; strain diagram; stress diagram in the shell layers; the N_x, N_y membrane force diagram and deflection of shell. Thisresults by experimental method on a full scale model of concrete have clarified the working of multi-layer doubly curved concrete shell roof. The experimental and simulation results are compared with each other and compared with the Sap2000 software.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1273-1280
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• 2003

In this paper, transparent dynamic photoelastic experimental hybrid method for propagating cracks in orthotropic material was developed. Using transparent dynamic photoelastic experimental hybrid method, we can obtain stress intensity factor and separate the stress components from only isochromatic fringe patterns without using isoclinics. When crack is propagated with constant velocity, the contours of stress components in the vicinity of crack tip in orthotropic material are similar to those of isotropic material or orthotropic material with stationary crack under the static load. Dynamic stress intensity factors are decreased as crack growths. It was certified that the dynamic photoelastic experimental hybrid method was very useful for the analysis of the dynamic fracture mechanics.

• Animal Bioscience
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• v.36 no.2
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• pp.248-255
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• 2023

Objective: Stress factors such as high temperatures, overcrowding, and diurnal temperature range exert profound negative effects on weight gain and productivity of broiler chickens. The potential of gamma aminobutyric acid (GABA) as an excitatory neurotransmitter was evaluated under various stress conditions in this study. Methods: The experiment was conducted under four different environmental conditions: normal, high temperature, overcrowded, and in an overcrowded-diurnal temperature range. The experimental groups were divided into (-) control group without stress, (+) control group with stress, and G50 group (GABA 50 mg/kg) with stress. Weight gain, feed intake, and feed conversion ratio were measured, and stress reduction was evaluated through hematologic analysis. Results: The effects of GABA on broilers in four experimental treatments were evaluated. GABA treated responded to environmental stress and improved productivity in all the experimental treatments. The magnitude of stress observed was highest at high temperature, followed by the overcrowded environment, and was least for the overcrowded-diurnal temperature range. Conclusion: Various stress factors in livestock rearing environment can reduce productivity and increase disease incidence and mortality rate. To address these challenges, GABA, an inhibitory neurotransmitter, was shown to reduce stress caused due to various environmental conditions and improve productivity.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.4
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• pp.315-322
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• 1982

The slab analogy method was introduced in the 1920's for the first time as a new experimental stress analysis method. Notwithstanding its theoretical propriety, this method has not been recognized as efficient one because of its difficulty in practical measurement of the slab curvature. In this paper, aiming at experimental determination of two-dimensional stress intensity factors(S. I. F) of arbitrarily shaped cracks which had been regarded as almost impossible by conventional method, the slab analogy was reevaluated. Measuring of slab curvature was replaced by three simple measuring factors to overcome vital slab-analogy's shortcoming by joint use of the shadow-moire method. A determination formula was also derived from the theory of fracture mechanics. By this newly exploited method, it was found that the slab analogy still has its great advantage in determination of S.I.F. of arbitrarily shaped cracks with considerable accuracy compared with existent experimental methods.

• Journal of Welding and Joining
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• v.21 no.7
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• pp.71-77
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• 2003

In this study, an investigation based on the superposition principle to predict residual stress redistribution caused by crack propagation itself initially through residual tensile stress field was performed by finite element method. The tendency in residual stress redistribution caused by crack propagation recognized both from the analytical results and experimental result was the residual stress concentration consecutively occurred in the vicinity of crack tip even the situation that the crack propagated to the region initially residual compressive stress existed. The software for the analysis is ABAQUS, which is a general purpose finite element package. The analytical method that attempt to take the plastic deformation at the crack tip due to tensile residual stress into the consideration of residual stress redistribution caused by crack propagation was proposed. The plastic zone size at the tip of fatigue crack and redistributed residual stresses were calculated by finite element method on the bases of the concept of Dugdale model. Comparing these analytical results with experimental results, it is verified that the residual stress redistribution caused by crack propagation can be predicted by finite element method with the proposed analytical method.

• Journal of Mechanical Science and Technology
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• v.18 no.5
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• pp.808-813
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• 2004

The stress analysis on orthotropic composite cylindrical shells with one circular or one elliptical cutout subjected to an axial force is carried out by using an analytical and experimental method. The composite cylindrical shell governing equation of the Donnell's type is applied to this study and all results are presented by the stress concentration factor. The stress concentration factor is defined as the ratio of the stress on the region around a cutout to the nominal stress of the shell. The stress concentration factor is classified into the circumferential stress concentration factors and the radial stress concentration factors due to the cylindrical coordinate of which the origin is the center of a cutout. The considered loading condition is only axial tension loading condition. In this study, thus, the maximum stress is induced on perpendicular region against axial direction, on the coordinate. Various cutout sizes are expressed using the radius ratio, (equation omitted), which is the radius of a cutout over one of the cylindrical shell. Experimental results are obtained using strain gages, which are attached around a cutout of the cylindrical shell. As the result from this study, the stress concentration around a cutout can be predicted by using the analytical method for an orthotropic composite cylindrical shell having a circular or an elliptical cutout.