• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.229-231
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• 2015

In pneumatic reactor, hydrodynamic relation between gas and solid is important and particle size has a significant effect on this relation. In this reason, we analyzed drying and calcine process with a corrected model by considering the effect of the particle size distribution(PSD) with different seven particle groups by particle size.

• Smart Structures and Systems
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• v.22 no.5
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• pp.527-546
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• 2018

This article presents an analysis into the nonlinear forced vibration of a micro cylindrical shell reinforced by carbon nanotubes (CNTs) with considering agglomeration effects. The structure is subjected to magnetic field and transverse harmonic mechanical load. Mindlin theory is employed to model the structure and the strain gradient theory (SGT) is also used to capture the size effect. Mori-Tanaka approach is used to estimate the equivalent material properties of the nanocomposite cylindrical shell and consider the CNTs agglomeration effect. The motion equations are derived using Hamilton's principle and the differential quadrature method (DQM) is employed to solve them for obtaining nonlinear frequency response of the cylindrical shells. The effect of different parameters including magnetic field, CNTs volume percent and agglomeration effect, boundary conditions, size effect and length to thickness ratio on the nonlinear forced vibrational characteristic of the of the system is studied. Numerical results indicate that by enhancing the CNTs volume percent, the amplitude of system decreases while considering the CNTs agglomeration effect has an inverse effect.

• Journal of the Korean Regional Science Association
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• v.31 no.1
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• pp.3-20
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• 2015

The objective of this study is to identify the applicability of urban network theory. The degree of network and city size of 163 Si-Guns in Korea are used to perform an empirical analysis for 2005 and 2010. The result indicates that the effect of city size (based on central place theory) is still larger than the network effect (based on urban network theory). However, the effects are different according to the industrial types. The size-based effectis more efficient in manufacturing sector, whereas the network-based effect is more efficient in service industry. The trend from 2005 to 2010 indicates that there is an increasing pattern in network-based effect and decreasing patternin size-based effect. It is necessary to recognize continual benefit of the sized-based effect, however it is also important to distinguish different characteristics of the functional form by the size and network. The feasibility of the urban network theory is tested in this study with the empirical analysis and recommends the importance of policy implication with recognition of the distinction between size and network-based effects.

• Journal of Korean Academy of Nursing
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• v.34 no.6
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• pp.1004-1013
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• 2004

Purpose: The purpose of this paper was to describe the characteristics of smoking prevention programs in Korea, to estimate overall effect size of Korean smoking prevention programs, and to investigate effect size variations by program modality and instruction method. Method: Meta-analysis was performed on2l programs in 20 studies. Result: The estimation of overall effect size for knowledge and attitude was not possible because effect sizes were not homogeneous in this meta-analysis. However, effect sizes of studies that were socially influential programs or active/interactive methods were larger than information-oriented programs or passive/non-interactive methods in the pictures. The effects for behavioral outcomes were generally not as positive and not statistically significant. Q statistics showed that variations among effect sizes within program modality and instruction method classifications were heterogeneous. Conclusion: The results from this meta-analysis support the continued use of socially influential programs and active/interactive methods for smoking prevention programs. Because behavioral effect might be the fundamental objective of smoking prevention programs, the present results indicate that smoking prevention programs should consider adopting more effective programs.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.1
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• pp.42-48
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• 2001

Over two decades, many researchers have performed studies on strength size effects in composite laminates under tensile and flexural loads. It is well known that there is a tendency for the strength of fibre-reinforced composites to decrease with increasing specimen size. Under compressive load, however, little work has been done on the effect of specimen size to failure strength. This is due to the fact that compressive testing of composite is very difficult. In this paper, the effect of the test specimen size on the compressive strength of composites containing open hole was considered using T300/924C, $>[45/-45/0/90]_{3S}$. For sizing test specimens, the in-plane scaling method is used i.e., the change of two- dimensional specimen area in specimen width and gauge length. The results clearly show that there is a hole size effect in the finite width plates. In addition, the specimens which have the same a/W(hole diameter/specimen width) exhibit a tendency of size effect. In contrast, test results of the unnotched specimens did not show a clear strength size effect.

• Geomechanics and Engineering
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• v.28 no.2
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• pp.135-143
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• 2022

Soils are natural granular materials whose mechanical properties differ according to the size and composition of the particles, so soils exhibit an obvious scale effect. Traditional soil mechanics is based on continuum mechanics, which can not reflect the impact of particle size on soil mechanics. On that basis, a matrix-reinforcing-particle cell model is established in which the reinforcing particles are larger-diameter sand particles and the matrix comprises smaller-diameter bentonite particles. Since these two types of particles deform differently under shear stress, a new shear-strength theory under direct shear that considers the stress concentration and bypass phenomena of the matrix is established. In order to verify the rationality of this theory, a series of direct shear tests with different reinforcing particle diameter and volume fraction ratio are carried out. Theoretical analysis and experimental results showed that the interaction among particles of differing size and composition is the basic reason for the size effect of soils. Furthermore, the stress concentration and bypass phenomena of the matrix enhance the shear strength of a soil, and the volume ratio of reinforcing particles has an obvious impact on the shear strength. In addition, the newly proposed shear-strength theory agrees well with experimental values.

• Journal of the East Asian Society of Dietary Life
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• v.7 no.2
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• pp.159-165
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• 1997

The primary objective of this study was to learn the effect of various sugar particle size and level on cookie spread, The effect of sugar particle size and level on sugarsnap cookie spread was studied. Three different particle sized sugars; powered sugar, granulated sugar and sanding sugar, were used for the cookie test baking with five different sugar levels; 30, 45, 60, 75 and 90% based on the weight of flour. In mixing process, 5 minutes of creaming time was used for cream making and then the specific gravity of cream was measured on the basis of each different sugar particle size and level. In the result, the specific gravity of cream was influenced by sugar particle size and sugar level. However, the specific gravity of cream had no influence on cookie dough specific gravity. Cookie spread was influenced by sugar particle size and sugar level. Greater cookie spread was obtained by decreasing sugar particle size and increasing sugar level resulted in increased spread. Therefore, selection of suitable sugar particle size and its use level can be factors in controlling spread and imparting desired packaging characteristics.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.545-553
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• 2020

Although networking behavior is an effective job search method to students, far too little attention has been paid to mechanisms explaining the antecedents and networking behavior. The goal of this study was to demonstrate the effect of the HEXACO personality dimensions on graduated students' job search networking behavior through their network size. A survey of 773 participants was conducted to assess personality traits, network size, and networking behavior. All constructs in the study were measured by 5-point Likert scales. This study employed a structural equation model to examine the proposed conceptual model and the correlations among variables. Results showed that the personality of emotionality negatively influence students' network size, while extraversion and agreeableness are positively associated with the scope of their social network. Second, the findings confirmed that network size is directly related to the level of looking-for job behavior, particularly networking behavior. Finally, our results explored that network size played the mediating effect on how personality traits affect networking behavior. These findings suggest that network size is a dynamic mechanism that helps to understand the correlation between personality traits and job search networking behavior. The theoretical and practical implication of the study, as well as the future research direction were discussed.

• Journal of the Korean Society of Safety
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• v.13 no.4
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• pp.292-299
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• 1998

In this study, the size effect in flexural and shear behaviors of reinforced concrete beams with stirrup has been studied. The specimens of different size with same longitudinal reinforcement ratio are tested. The major variables of test include the size(relative depth) of the members as well as the longitudinal reinforcement ratios. The nominal resistances in flexure and shear are obtained for various sizes and steel ratios. It is found from the present study that the size effect is also very pronounced for the flexural resistance in reinforced concrete structures. The prediction formulas for the size effect of reinforced concrete beams in flexure and shear are proposed. The proposed equations agree relatively well with experimental data. The present study will provide useful bases for more accurate analysis and design of reinforced concrete structures.

• Structural Engineering and Mechanics
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• v.26 no.2
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• pp.127-150
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• 2007

The objective of this paper is to develop a finite element procedure for predicting the compressive strength and ultimate axial strain of Carbon Fiber Reinforced Plastics (CFRP) confined circular concrete columns and to study the effective parameters of confinement efficiency for helping design of CFRP retrofit technology. The behavior of concrete confined with CFRP is studied using the nonlinear finite element method. In this paper, effects of column size, CFRP volumetric ratio and plain concrete strength are studied. The confined concrete nonlinear constitutive relation, concrete failure criterion and stiffness reduction methodology after concrete cracking or crushing are adopted. First, the finite element model is verified by comparing the numerical solutions of confined concrete with experimental results. Then the effects of column size, CFRP volumetric ratio and plain concrete strength on the peak strength and ductility of the confined concrete are considered. The results of parametric study indicate that the normalized column axial strength increases with increasing CFRP volumetric ratio, but without size effect for columns with the same CFRP volumetric ratio. As the same, the increase in column ductility depends on CFRP volumetric ratio but without size effect for columns with the same CFRP volumetric ratio.