• Research in Community and Public Health Nursing
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• v.7 no.1
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• pp.100-117
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• 1996

The purpose of the survey was to find out the prevalence rate and related factors for low back pain of nurses and to develop educational program for prevention of the low back pain. The subjects of the survey were 593 nurses of general hospitals in Tae-gu City. The survey was conducted from June 10, 1994 to October 3, 1994. The questionnaire included 34 question items concerning general characteristics, factors related to low back pain, physical nursing activities, and characteristics of low back pain. The results were as follows : 1. Among 593 of subjects, the prevalence rate of low back pain showed 62.1%. 2. In relation of health related life activities and low back pain prevalence, self-reported health state was highly significant(P=.000). 3. In relation of work environmental factors and low back pain prevalence, job satisfaction (P=.026), job stress(P=.020), and workload(P=.002) were significant. 4. In relation of physical nursing activities and low back pain prevalence, bending (P=.000), trunk twisting(P=.003), stretching(P=.006), and pulling and pushing(P=.046) were significant. 5. Physical nursing activities inducing back stress was varicant according to wards. The results of this study pointed out that the subjects' low back pain prevalence was related to the work-related physiologic and psychologic factors. Therefore, for the effective prevention of low back pain, both practicing the body mechanics and raising the morale of the nurses are needed in educational program.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.3
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• pp.82-94
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• 1988

A growing attention has been paid to the optimum design of structures in recent years. Most studies on the optimum design of reinforced concrete structures has been mainly focussed to the design of structural members such as beams, slabs and columns, and there exist few studies that deal with the optimum design of large-scale concrete shell structures. The purpose of the present investigation is, therefore, to set up an efficient optimum design method for the large-scale reinforced concrete cylindrical shell structures like intake tower of reservoir. The major design variables are the dimensions and steel areas of each member of structures. The construction cost which is compo8ed of the concrete, steel, and form work costs, respectively, is taken as the objective function. The constraint equations for the design of intake-tower are derived on the basis of strength design method. The results obtained are summarized as follows 1. The efficient optimlzation algorithrns which can execute the automatic optimum design of reinforced concrete intake tower based on the strength design method were developed. 2. Since the objective function and design variables were converged to their optimum values within the first or second iteration, the optimization algorithms developed in this study seem to be efficient and stable. 3. When using the strength design method, the construction cost could be saved about 9% compared with working stress design method. Therefore, the reliability of algorithm was proved. 4. The difference in construction cost between the optimum designs with substructures and with entire structure was found to be small and thus the optimum design with substructures may conveniently be used in practical design. 5. The major active constraints of each structural member were found to be the 'bending moment constraint for slab, the minimum longitudinal steel ratio constraint for tower body and the shearing force, bending moment and maximum eccentricity constraints for footing, respectively. 6. The computer program developed in the present study can be effectively used even by an uneiperienced designer for the optimum design of reinforced concrete intake-tower on the basis of strength design method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.2
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• pp.181-190
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• 2005

The objective of this work is to study the flexural strengthening effectiveness of Carbon Fiber Mesh (CFM) in reinforced concrete beams. Flexural strengthening for a simply supported reinforced concrete (RC) beam using CFM is developed by bonding CFM to the soffit of the beam. In this experimental program, five medium-sized reinforced concrete beams strengthened with CFM are tested in bending to evaluate reinforcing effects of the CFM. The beams are designed to have high shear capacity so that expected dominant failure mode of specimens is bending. The reinforcing effect of CFM is small at crack initiation, but is considerable in flexural rigidity of the beam after crack initiation. In comparing the behaviors of strengthened and virgin beams each other, it is shown that the strength of RC beams can be enhanced by attaching CFM. A fairly good agreement between the measured values and the calculated ones is obtained at both the cracking strength and yield strength of the strengthened beams.

• Structural Engineering and Mechanics
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• v.67 no.5
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• pp.527-544
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• 2018

In this paper, the effect of homogenization models on stress analysis is presented for functionally graded plates (FGMs). The derivation of the effective elastic proprieties of the FGMs, which are a combination of both ceramic and metallic phase materials, is of most of importance. The majority of studies in the last decade, the Voigt homogenization model explored to derive the effective elastic proprieties of FGMs at macroscopic-scale in order to study their mechanical responses. In this work, various homogenization models were used to derive the effective elastic proprieties of FGMs. The effect of these models on the stress analysis have also been presented and discussed through a comparative study. So as to show this effect, a refined plate theory is formulated and evaluated, the number of unknowns and governing equations were reduced by dividing the transverse displacement into both bending and shear parts. Based on sinusoidal variation of displacement field trough the thickness, the shear stresses on top and bottom surfaces of plate were vanished and the shear correction factor was avoided. Governing equations of equilibrium were derived from the principle of virtual displacements. Analytical solutions of the stress analysis were obtained for simply supported FGM plates. The obtained results of the displacements and stresses were compared with those predicted by other plate theories available in the literature. This study demonstrates the sensitivity of the obtained results to different homogenization models and that the results generated may vary considerably from one theory to another. Finally, this study offers benchmark results for the multi-scale analysis of functionally graded plates.

• Steel and Composite Structures
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• v.26 no.4
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• pp.513-531
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• 2018

In this article, static, buckling and free vibration analyses of a sinusoidal micro composite beam reinforced by single-walled carbon nanotubes (SWCNTs) with considering temperature-dependent material properties embedded in an elastic medium in the presence of magnetic field under transverse uniform load are presented. This system is used at micro or sub micro scales to enhance the stiffness of micro composite structures such as bar, beam, plate and shell. In the present work, the size dependent effects based on surface stress effect and modified strain gradient theory (MSGT) are considered. The generalized rule of mixture is employed to predict temperature-dependent mechanical and thermal properties of micro composite beam. Then, the governing equations of motions are derived using Hamilton's principle and energy method. Numerical results are presented to investigate the influences of material length scale parameters, elastic foundation, composite fiber angle, magnetic intensity, temperature changes and carbon nanotubes volume fraction on the bending, buckling and free vibration behaviors of micro composite beam. There is a good agreement between the obtained results by this research and the literature results. The obtained results of this study demonstrate that the magnetic intensity, temperature changes, and two parameters elastic foundations have important effects on micro composite stiffness, while the magnetic field has greater effects on the bending, buckling and free vibration responses of micro composite beams. Moreover, it is shown that the effects of surface layers are important, and observed that the changes of carbon nanotubes volume fraction, beam length-to-thickness ratio and material length scale parameter have noticeable effects on the maximum deflection, critical buckling load and natural frequencies of micro composite beams.

• Structural Engineering and Mechanics
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• v.68 no.4
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• pp.385-398
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• 2018

In the present paper, we offer a new flat shell finite element. It is the result of the combination of a membrane element and a bending element, both based on the strain-based formulation. It is known that $C^{\circ}$ plane membrane elements provide poor deflection and stress for problems where bending is dominant. In addition, they encounter continuity and compliance problems when they connect to C1 class plate elements. The reach of the present work is to surmount these problems when a membrane element is coupled with a thin plate element in order to construct a shell element. The membrane element used is a triangular element with four nodes, three nodes at the vertices of the triangle and the fourth one at its barycenter. Each node has three degrees of freedom, two translations and one rotation around the normal. The coefficients related to the degrees of freedom at the internal node are subsequently removed from the element stiffness matrix by using the static condensation technique. The interpolation functions of strain, displacements and stresses fields are developed from equilibrium conditions. The plate element used for the construction of the present shell element is a triangular four-node thin plate element based on Kirchhoff plate theory, the strain approach, the four fictitious node, the static condensation and the analytic integration. The shell element result of this combination is robust, competitive and efficient.

• Computers and Concrete
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• v.25 no.1
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• pp.37-57
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• 2020

This work investigates a new type of quasi-3D hyperbolic shear deformation theory is proposed in this study to discuss the statics and free vibration of functionally graded porous plates resting on elastic foundations. Material properties of porous FG plate are defined by rule of the mixture with an additional term of porosity in the through-thickness direction. By including indeterminate integral variables, the number of unknowns and governing equations of the present theory is reduced, and therefore, it is easy to use. The present approach to plate theory takes into account both transverse shear and normal deformations and satisfies the boundary conditions of zero tensile stress on the plate surfaces. The equations of motion are derived from the Hamilton principle. Analytical solutions are obtained for a simply supported plate. Contrary to any other theory, the number of unknown functions involved in the displacement field is only five, as compared to six or more in the case of other shear and normal deformation theories. A comparison with the corresponding results is made to verify the accuracy and efficiency of the present theory. The influences of the porosity parameter, power-law index, aspect ratio, thickness ratio and the foundation parameters on bending and vibration of porous FG plate.

• Journal of the Korea Fashion and Costume Design Association
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• v.14 no.2
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• pp.157-169
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• 2012

The aim of this study is to serve as a stepping stone to outlook changes in men's fashion based on gender characteristics and the design proposal as a reference to shirts design for men's wear brands. This study is a theoretical work extracted from related books, dissertations, and web- resources referenced. Research method is as followed. It is based on the four main collections from S/S 2001 to S/S 2010 and selected designer brands among the most influential foreign men's fashion designer brands which have show cased their collections of 19 seasons in the last 10 years. These are what the study has found out. Firstly, the shoulder-line which used to be straight and hard in men's dress shirt has changed to comfortable curved line which falls from the shoulder to sleeve. Silhouettes were mainly shaped to an hourglass or slim silhouette representing the body curve line. Unlike how the masculine beauty was emphasized through the straight line, men's dress shirts nowadays used curved line for softness. Secondly, there were various designs with decorations added to the basic structure, making it no different from women's blouse and blurring the line between men's and women's fashion. Thirdly, colors were normally in bright ones. Tones were often in pale tone which used to be the women's color. Also choosing shades of yellow or red was a remarkable change in men's wear. Fourthly, through varying patterns and texture there were many shirts that gave clear visual effect. There were approximately equal portions of patterns with feminine image like natural patterns, abstract patterns, or small patterns and patterns with masculine image.

• The Korean Journal of Community Living Science
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• v.23 no.2
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• pp.137-144
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• 2012

This study was undertaken to develop protective gloves for rose farmers who work on thorny plant in Korea. Prototype of protective gloves was designed and evaluated in terms of thermal comfort and mobility. Gloves were made with arm protectors attached to them, so that they could protect the lower part of arms, and rubber bands were inserted into the arm protectors for them not to slip down. The bending part of each finger was punched in order to give ventilation. Also, the bending parts of the fingers in the upper and lower part of gloves were inserted with sponges and were stitched together in order to enhance gripping movement. According to compared evaluation of the developed gloves and the existing gloves, temperature inside the gloves didn't show any significant differences, but humidity inside the gloves showed significant differences. There were significant differences in terms of comparison of objective mobility, that is, pegboard run-time and grip power, from statistical aspects. In addition, a comparison of subjective discomfort showed significant differences and so the suitability of developed gloves was proved.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5C
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• pp.221-229
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• 2012

Steel ribs such as H-beam or lattice girder are often reinforced to secure the stability of NATM tunnel when the ground is in the bad condition. When designing, however, steel ribs are not often taken into consideration on the numerical analysis when they are regarded as temporary tunnel supports until shotcrete shows its best performance or if they are, there are various modeling methods. This study shows behavior and loading capacity of steel ribs and shotcrete through the strength test on the bending, pressure and full-scaled. Also, we conducted and analyzed the experiment of composite member consisting of shotcrete and steel ribs under the same condition. Through the result, we can find the fact that shotcrete and steel ribs do not work as one unit because of slipping on the boundary. Also, when numerical analyzing, it was concluded that steel ribs cover all bending moment and shotcrete and steel ribs share with axial force according to the compressive strength.