• Steel and Composite Structures
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• v.26 no.5
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• pp.649-662
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• 2018

In this study, based on the three-dimensional theory of elasticity, free vibration characteristics of sandwich sectorial plates with multiwalled carbon nanotube-(MWCNT)-reinforced composite core are considered. Modified Halpin-Tsai equation is used to evaluate the Young's modulus of the MWCNT/epoxy composite samples by the incorporation of an orientation as well as an exponential shape factor in the equation. The exponential shape factor modifies the Halpin-Tsai equation from expressing a straight line to a nonlinear one in the MWCNTs wt% range considered. In this paper, free vibration of thick functionally graded sandwich annular sectorial plates with simply supported radial edges and different circular edge conditions including simply supported-clamped, clamped-clamped, and free-clamped is investigated. A semi-analytical approach composed of two-dimensional differential quadrature method and series solution are adopted to solve the equations of motion. The material properties change continuously through the core thickness of the plate, which can vary according to a power-law, exponentially, or any other formulations in this direction. This study serves as a benchmark for assessing the validity of numerical methods or two-dimensional theories used to analysis of laminated sectorial plates.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.393-398
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• 2002

Rubber isolator has properties that can adjust easily stiffness and can be formed various shape. Also, it has high damping and is effective about structure-borne noise at high frequency range, So, rubber mount has widely used to isolate vibration at industrial equipment and construction field. However, rubber material is nonlinear and require enough consideration about shape factor whenever it is designed. The purpose of this paper is to develop conical rubber mount using compression and shear elasticity. The first, the dimension of mount is calculated by theoretical analysis considering design condition and static characteristics have been analyzed by FEM method. In addition, the fatigue test of rubber mount is performed to get reliability for product life and dynamic stiffness test is executed to get dynamic magnification factor. Finally, transmissibility test of vibration isolator has been carried out to suggest normal quantity data about vibration isolation.

• Structural Monitoring and Maintenance
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• v.6 no.2
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• pp.147-159
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• 2019

In present article, a size-dependent refined thick beam element has been established based upon nonlocal elasticity theory. Next, it is used to explore vibration response of porous metal foam nanobeams on elastic medium. The established beam element introduces ten degrees of freedom. Different porosity distributions called uniform, symmetric and asymmetric will be employed. Herein, introduced thick beam element contains shear deformations without using correction factors. Convergence and verification studies of obtained results from finite element method are also provided. The impacts of nonlocality factor, foundation factors, shear deformation, slenderness ratio, porosity kinds and porosity factor on vibration frequencies of metal foam nano-sized beams have been explored.

• Structural Engineering and Mechanics
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• v.78 no.4
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• pp.379-386
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• 2021

A numerical and computer simulation for dynamic stability analysis of graded porous nanoplates has been provided using a Chebyshev-Ritz-Bolotin approach. The nanoplate has been formulated according to the nonlocal elasticity and a 3-unkown plate model capturing neutral surface location. All of material properties are assumed to be dependent of porosity factor which determines the amount or volume of pores. The nano-size plate has also been assumed to be under temperature and moisture variation. It will be shown that stability boundaries of the nanoplate are dependent on static and dynamical load factors, porosity factor, temperature variation and nonlocal parameter.

• Journal of the Korean Home Economics Association
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• v.51 no.2
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• pp.161-171
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• 2013

The purpose of this research was to examine the subjective evaluation of sensory images and preferences according to the mechanical properties of linen and ramie fabrics for summer shirts. 54 male and female teachers evaluated the sensory images and preferences of 6 specimens of linen and ramie fabrics sold on the market. For statistical analysis, factor analysis, Mann-Whitney and Kruskal-Wallis test, Pearson correlation, and regression were used. The results were as follows: The sensory images of shirt fabrics were classified into 5 factors: 'smoothness', 'stiffness', 'elasticity', 'dry/coolness', and 'wetness'. There were partially significant differences by the gender and age in the sensory images for the shirt fabrics. Females were more sensitive than males for the 'stiffness', 'elasticity', and 'wetness' factor and the evaluators in their 20's felt fabrics were stiffer. The sensory images showed many correlations with the mechanical properties of fabric mostly. The preferences of tactile and purchase were no different according to the gender and age. They preferred a thin and soft sensory image as like ramie/cotton blended fabric and bamboo fabric for summer shirts. The significant sensory image factors affecting tactile preference were 'smoothness', 'dry/coolness', and 'elasticity', and the ones affecting purchase preference were 'smoothness', 'stiffness', 'dry/coolness', and 'elasticity'. W, WT, MMD, and G properties of the mechanical properties of fabrics affected the tactile preference for summer shirt fabrics.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.1
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• pp.40-48
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• 2024

This study judged that although milk with various properties is currently being released, the growth rate of the milk market has not changed significantly, and the reason for this is that a substitution relationship has been formed between existing white milk and milk with various properties and they are competing with each other. The purpose of this study was to provide implications for the future growth of the milk market by identifying the relationship between diversified milk attributes. As a research method for this purpose the own price elasticity, cross-price elasticity, and expenditure elasticity of each attribute were derived through the LA/AIDS demand system model, and an analysis of consumers' milk purchasing factors was conducted through factor analysis. Based on the analysis results, it presented implications for growth in the milk market, such as expanding products with great differentiation in attributes such as flavor, plant and lactose-free properties, establishment of marketing strategies targeting consumers with children, and expansion of online malls.

• The Journal of Korean Obstetrics and Gynecology
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• v.25 no.4
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• pp.46-55
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• 2012

Objectives: It is well known that genetic factors and environmental factors play major role in aging skin. In general, son and daughter take after their parents in appearance. But comparability of skin properties in Korean family has not been well estimated. So we evaluated the correlation of skin properties in Korean mother-daughter pairs. Methods: 10 couples of mother and daughter pair(n=20) participate in this study. Mothers and daughters were aged $50.6{\pm}2.459$ and $23.8{\pm}2.15$ years, respectively. Skin moisture, sebum, skin color and elasticity is measured using non-invasive method : Corneometer CM825, Sebumeter(MPA580), Mexameter MX18, Cutometer MPA580. Statistical analysis program we used is Minitab 14 Korea. Results: The Skin moisture of mother group was significantly higher than daughter group. And skin elasticity(R2) of the daughter group was significantly higher than mother group. In the results of correlation analysis between mother and daughter pairs, skin elasticity(R2) had high positive correlation(r=0.729, p=0.026). But skin moisture, sebum, melanin index, erythema index and skin elasticity(R5) did not be confirmed a significant correlation. Conclusions: Skin elasticity(R2) is the only factor that showed high positive correlation significantly in mother and daughter pairs. Mother and daughter share the genetic factors and environmental factors that influence skin aging. So, mother's aging pattern will be a good guide for anti-aging of daughters.

• Fashion & Textile Research Journal
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• v.24 no.6
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• pp.789-800
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• 2022

This study investigates the effect of recovery elasticity of beauty college students on university life adaptation during COVID-19. Further, the mediating effect of grit in relation to recovery elasticity and university life adaptation is analyzed. Survey data of 223 students (female: 192; male: 31) were collected for multiple and intermediate regression analyses using SPSS 24.0. The results reveal a static correlation between the lower factors of resilience, glittery, and adaptation to college life and that the resilience of junior college students in the beauty department had a static effect on grit and their adaptation to college life. Passion, a subordinate factor of grit, is mediated by the effect of grit on the relationship between resilience and adaptation to university life. However, perseverance, another subordinate factor of grit, did not have any such mediating effect. These results confirm the importance of grit, particularly passion, for resilience and adaptation to college life. It was confirmed that resilience was due to college life adaptation of beauty department students, and it was confirmed that passion, a sub-factor of grit, also had a mediating effect. Therefore, it is judged that resilience induces physical and mental adaptation, interpersonal adaptation, and academic adaptation necessary for college life, and works in many ways to improve the quality of life of beauty department junior college students. Instructors should consider developing educational programs for improving recovery elasticity and grit to help students better adapt to university life.

• Journal of Korea Port Economic Association
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• v.24 no.4
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• pp.47-70
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• 2008

The purpose of this study is to estimate total factor productivity(TFP) growth by stochastic frontier function and to grasp contributing factors of its growth rate by decomposing the total factor productivity into efficiency change, technical progress, scale change, and allocation change. Annual growth rate of total factor productivity for 1990-2003 is 0.019 (1.9%), higher than that of overall industry (0.010). The main component of TFP growth is not efficiency change but technical progress. Contributing factors of total factor productivity growth are change of allocation efficiency in port industry, technical progress in sea-transportation industry, and change of scale efficiency in transportation-equipment industry. The change of total factor productivity shows a decreasing trend since late in the 1990s. The annual technical efficiency of port-logistics industry is less than that of overall industry. Capital elasticity for output (0.391) is higher than labor elasticity (0.227), but scale economy of port-logistics industry is 0.618, which is far from optimal scale economy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.502-502
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• 2007

A catenary system should be designed to have an uniform elasticity over a span in order to maintain the lowest possible loss of contact between a pantograph and a contact wire. A elasticity uniformity of a catenary can be regarded as a important design factor used for predicting the current collection performance for a catenary. There are a couple of formulas to calculate the degree of elasticity uniformity of a catenary according to the literature survey. The effectiveness of these formulas is reviewed by performing catenary elasticity and loss of contact analysis for various different configurations of catenary systems using a beam element based FEM program. The results reveals that these formulas are not suitable to predict the current collection performance for a catenary. Therefore, a new formula based on the standard deviation of the elasticity over a span is proposed in this study. The analysis results show that the new formula for an elasticity uniformity of a catenary is very effective in predicting the current collection performance for a catenary.