• 대한조선학회논문집
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• 제55권4호
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• pp.341-349
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• 2018

Recently, it has been reported that the whipping response, which is the elastic phenomenon of the ship, may be one of the causes of the ship accident. Unfortunately, the commonly used methodology for evaluating the whipping effect effectively has not been developed yet. In this study, we developed a procedure to estimate the whipping effect of hull in actual design stage. Fluid-structure interaction analysis was performed for a dominant short term sea state to obtain the time series data of vertical wave bending moment including the whipping response by slamming. In order to estimate the whipping effect by using the time series, some signal processing and statistical techniques such as low pass filtering, Weibull fitting and so on, were applied. the hydro-elasticity analysis was performed on container ships of various sizes to evaluate the whipping effect. The parameters that can affect the response of the hull vibration was selected and the effect of these parameters on whipping was analyzed.

• Structural Engineering and Mechanics
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• 제64권6권
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• pp.819-826
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• 2017

The effects of thermocycling procedure and material shade on the mechanical properties and wear resistance of resin-based dental restorative materials are investigated. The modulus of elasticity, hardness, plasticity index and wear resistance are determined for the conventional composite, the nanohybrid composite and the nanofilled dental composites. Disc-shape samples are prepared from each material to investigate the effects of thermocycling procedure on the mechanical properties and wear resistance of different types of dental restorative materials. In this respect, a group of samples is thermocycled and the other group is stored in ambient conditions. Then nano-indentation and nano-scratch tests are performed on the samples to measure their mechanical properties and wear resistance. Results show that the A1E shade of the dental nanocomposite possesses higher modulus of elasticity and hardness values compared to the two other shades. According to the experimental results, the mean values for the modulus of elasticity and hardness of the A1E shade of the nanocomposite are 13.71 GPa and 1.08 GPa, respectively. The modulus of elasticity and hardness of the conventional dental composite increase around 30 percent in the oral environment due to the moisture and temperature changes. The wear resistance of the dental composites is also significantly affected by moisture and temperature changes in the oral conditions. It is observed that thermocycling has no significant effect on the hardness, plasticity index and wear resistance of the nanohybrid composite and the nanocomposite dental materials.

• 사회복지연구
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• 제41권1호
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• pp.65-84
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• 2010

불평등 지수의 분해란 사회 전체의 불평등을, 이에 영향을 미치는 개별원천들로 분해하여, 그 원인을 밝히고자 하는 것이다. 기존에는 개별요인들이 전체 불평등에서 정량적으로 차지하는 절대적 기여도에만 관심을 가져왔다. 그러나 불평등 완화를 위한 정책을 효과적으로 수행하기 위해서는, 개별원천들이 가지고 있는 한계적인 불평등 효과를 아는 것이 더 중요할 것으로 생각된다. 본 연구에서는 이를 위하여 대표적인 불평등 지수라 할 수 있는 지니계수를 소득원천별 혹은 사회복지 프로그램별로 분해하고, 각각의 Gini Income Elasticity(GIE)를 계산하였다. 분석결과에 따르면, '상용근로자 소득'과 '고용주 및 자영자 소득'의 GIE가 각각 1.205와 1.867로, 이들의 증가는 사회 전체의 불평등을 악화시킬 수 있는 소득원천들로 분류되었다. 이러한 GIE를 이용한 분석방법은 소득원천 혹은 사회복지 프로그램들의 불평등 효과를 분석하는데 있어서 하나의 유용한 방법의 될 수 있을 것이다.

• 한국지역사회생활과학회지
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• 제26권1호
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• pp.75-85
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• 2015

This study investigates the impact of livestock diseases, including FMD(foot-and-mouth disease) and MCD(mad-cow disease), on pork demand in Korea. TV news stories about the livestock diseases were considered as negative advertising, and therefore the carry-over effect of negative advertising was combined with the pork demand model in conjunction with an exponential distributed lag function. The asymmetry hypothesis was imposed, however it was accepted that demand response does not show different sensitivities to increases and decreases in the livestock disease news. FMD news had a negative effect on pork demand, whereas MCD news had a positive effect, yet FMD news had a greater effect on pork demand than MCD news. The pork demand elasticity estimates for FMD and MCD news were -0.0071 and 0.0028, respectively. The cross-elasticity of the imported beef price to pork demand was highly inelastic, but it was elastic during the beef import embargo.

• 대한치과교정학회지
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• 제50권6호
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• pp.391-400
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• 2020

Objective: Increased gingival elasticity has been implicated as the cause of relapse following orthodontic rotational tooth movement and approaches to reduce relapse are limited. This study aimed to investigate the effects of sulforaphane (SFN), an inhibitor of osteoclastogenesis, on gene expression in gingival fibroblasts and relapse after rotational tooth movement in beagle dogs. Methods: The lower lateral incisors of five beagle dogs were rotated. SFN or dimethylsulfoxide (DMSO) were injected into the supra-alveolar gingiva of the experimental and control group, respectively, and the effect of SFN on relapse tendency was evaluated. Changes in mRNA expression of extracellular matrix components associated with gingival elasticity in beagles were investigated by real-time polymerase chain reaction. Morphology and arrangement of collagen fibers were observed on Masson's trichrome staining of buccal gingival tissues of experimental and control teeth. Results: SFN reduced the amount and percentage of relapse of orthodontic rotation. It also decreased the gene expression of lysyl oxidase and increased the gene expression of matrix metalloproteinase (MMP) 1 and MMP 12, compared with DMSO control subjects. Histologically, collagen fiber bundles were arranged irregularly and were not well connected in the SFN-treated group, whereas the fibers extended in parallel and perpendicular directions toward the gingiva and alveolar bone in a more regular and well-ordered arrangement in the DMSO-treated group. Conclusions: Our findings demonstrated that SFN treatment may be a promising pharmacologic approach to prevent orthodontic rotational relapse caused by increased gingival elasticity of rotated teeth in beagle dogs.

• Smart Structures and Systems
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• 제20권3호
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• pp.351-368
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• 2017

To peruse the free vibration of curved functionally graded piezoelectric (FGP) nanosize beam in thermal environment, nonlocal elasticity theory is applied for modeling the nano scale effect. The governing equations are obtained via the energy method. Analytically Navier solution is employed to solve the governing equations for simply supported boundary conditions. Solving these equations enables us to estimate the natural frequency for curved FGP nanobeam under the effect of a uniform temperature change and external electric voltage. The results determined are verified by comparing the results by available ones in literature. The effects of various parameters such as nonlocality, uniform temperature changes, external electric voltage, gradient index, opening angle and aspect ratio of curved FGP nanobeam on the natural frequency are successfully discussed. The results revealed that the natural frequency of curved FGP nanobeam is significantly influenced by these effects.

• 한국식품조리과학회지
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• 제20권3호
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• pp.227-234
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• 2004

To determine the optimum mixing conditions of home made pasta with chives, samples were prepared with various compounding ratios of Durum wheat semolina (99, 198 and 297g), chive paste (27, 45 and 63g) and egg (72, 81 and 90g) using a central composite design, and sensory evaluations were performed and considered using a response surface methodology. The optimum mixing rates of Durum wheat semolina, chive paste and egg were 191.10, 45.53 and 80.98g for color, 149.00, 47.00 and 73.24g for flavor, 185.06, 43.99 and 81.18g for elasticity, and 188.69, 42.32 and 82.36g for overall quality. These results show that Chive paste effect the color and flavor, and Durum wheat semolina and egg effect the elasticity and overall quality.

• Structural Engineering and Mechanics
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• 제65권4호
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• pp.465-476
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• 2018

This article investigates buckling behavior of a multi-phase nanocrystalline nanobeam resting on Winkler-Pasternak foundation in the framework of nonlocal couple stress elasticity and a higher order refined beam model. In this model, the essential measures to describe the real material structure of nanocrystalline nanobeams and the size effects were incorporated. This non-classical nanobeam model contains couple stress effect to capture grains micro-rotations. Moreover, the nonlocal elasticity theory is employed to study the nonlocal and long-range interactions between the particles. The present model can degenerate into the classical model if the nonlocal parameter, and couple stress effects are omitted. Hamilton's principle is employed to derive the governing equations and the related boundary conditions which are solved applying an analytical approach. The buckling loads are compared with those of nonlocal couple stress-based beams. It is showed that buckling loads of a nanocrystalline nanobeam depend on the grain size, grain rotations, porosities, interface, elastic foundation, shear deformation, surface effect, nonlocality and boundary conditions.

• Advances in aircraft and spacecraft science
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• 제7권6호
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• pp.517-536
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• 2020

The present study investigates axial vibration of a FG nanobeam using nonlocal elasticity theory under clamped-clamped and clamped-free boundary conditions. Power law, exponential law and sigmoid law are applied as grading laws to examine the effect of the material distribution on axial vibration of the FG nanobeam. A parametric study was done to examine the effect of length scale on the dynamic behavior of the structure and the results are presented. It was observed that consideration of the nonlocal length scale is essential when analyzing the free vibration of a FG nanobeam. The results of the present study can be used as benchmarks in future studies of FG nanostructures.

• 콘크리트학회논문집
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• 제11권4호
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• pp.117-127
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• 1999

In concrete incorporating high volume ground granulated blast-furnace slag that has frozen at early age, to evaluated the results of resistance to freezing and thawing is very difficult because the hydration of the concrete increases over the duration of rapid freezing and thawing test. Hence, the dynamic modulus of elasticity of specimens after freezing and thawing will be favorable results unless the hydration effect is taken into consideration. In this study, a method of evaluating to the resistance to freezing and thawing of concrete subjected freezing at early age, in which the effect of hydration is modified for its increase during rapid freezing and thawing test, is investigated.