• Elastomers and Composites
• /
• v.54 no.3
• /
• pp.209-219
• /
• 2019

It is important to analyze crosslink densities of rubber articles because the physical properties are dependent on the crosslink densities. In this paper, analytical techniques for the measurement of crosslink densities of rubber vulcanizates are described. The most widely used method to measure the crosslink density is a swelling method combined with the Flory-Rehner equation. Application of the interaction parameter (${\chi}$) of rubber and swelling solvent is critical because the crosslink density is absolutely dependent on the ${\chi}$ value. Methods for obtaining ${\chi}$ employ not only solubility parameters of the polymer and swelling solvent but also inverse gas chromatography (IGC). The solubilities of rubbers can be obtained using micro differential scanning calorimetry (${\mu}DSC$), intrinsic viscosity measurement, and UV-visible spectroscopy. Nuclear magnetic resonance (NMR) spectroscopy has been also used for the measurement of the crosslink density using the $T_2$ relaxation time, which is determined by spin-spin relaxation in solid-state NMR. For sulfur-cured rubber vulcanizates, crosslink densities according to the crosslink types of mono-, di-, and polysulfides are measured by treating the rubber samples with a chemical probe composed of thiol and amine compounds. Measurement methods of physical crosslinking by filler, crystallization, and ionic bonding have also been introduced.

• Applied Chemistry for Engineering
• /
• v.18 no.5
• /
• pp.424-432
• /
• 2007

With the aiming to improve the comprehension of an expansion process of perlite, a numerical study has been carried out, concerning a water vapor bubble growth in a softened perlite melt. Isothermal case of the model is investigated and compared with the experimental results. Water content is an intrinsic parameter in a perlite expansion. With increasing water content, the expansion time is faster. But it can not be changed easily in an industrial process. Initial temperature is a changeable parameter in an industrial process. Higher initial temperature hastens the expansion time and this can be a key parameter in an industrial process. Experimental results are observed by SEM. Increasing initial temperature, perlite shape becomes close to sphere. Calculated bubble growth results are compared with experimental results. Packing density is measured and compared with simulated results. These results indicate that some other factors are applied on the model during heat transformation to work.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.04a
• /
• pp.171-176
• /
• 2004

Image matching is fundamental process in photogrammetry and computer vision to identify and to measure corresponding features on the multiple images. Uniqueness of the matching entities and robustness of the algorithm are the key issues that have influence on quality of the matching result. The optimal solution could be obtained by utilizing appropriate matching entities in the first place. In this study, candidate matching points were extracted by interest operator, and an area-based matching method was applied with characteristics of the gray value distribution as the matching entities. The characteristic information is based on the concept of "intrinsic image" (or parameter image). The information was utilized as additional and/or complementary matching entities. Matching on interest points with the characteristic information resulted in high quality of matching because matching windows were created with surrounding pixels of the interest points that contain distinct and unique features. The experiment shows that matching quality and reliability increase by exploiting interest operator, and the characteristic information has potential to be matching entity.

• Proceedings of the IEEK Conference
• /
• 2002.07a
• /
• pp.627-630
• /
• 2002

A methodology based on factorial design and Motto Carlo methods is developed and implemented for incorporating uncertainties within a multiphase subsurface flow and transport simulation system. Due to uncertainties in intrinsic permeability and longitudinal dispersivity, the predicted output is also uncertain based on the well-developed multiphase compositional simulator. The simulation results reveal that the uncertainties in input parameters pose considerable influences on the predicted output, and the mean and variance of permeability will have significant impacts on the modeling output. The proposed method offers an effective tool for evaluating uncertainty in multiphase flow simulation system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2017.06a
• /
• pp.237-240
• /
• 2017

최근 바둑에 대한 관심이 급증함에 따라 바둑에 관련된 연구가 많이 진행되고 있다. 바둑에 관련된 연구가 진행 되기 위해서는 많은 양의 바둑 데이터를 취득할 필요가 있다. 바둑 데이터 중 아직도 사람의 도움없이 취득하기 어려운 데이터로는 대표적으로 기보 데이터가 있다. 따라서 기보를 자동으로 저장하는 연구가 활발하게 진행 되고 있다. 기보를 자동으로 저장하는 연구 중 바둑돌이 착수될 위치를 예측하여 기보를 저장하는 시스템은 카메라의 정보를 취득하는 것으로부터 시작된다. 많은 양의 데이터를 수집하기 위해서는 일반 사용자가 사용할 수 있는 어플리케이션의 역할이 중요하다. 하지만 카메라의 정보를 취득하는 것은 어플리케이션의 환경을 구축하는데 어려움을 야기한다. 따라서 본 논문은 어플리케이션의 환경 구축 문제점인 카메라의 정보를 바둑판 최 외각 네 끝점과 비교적 간단한 방법으로 예측하는 방법을 제안한다.

• Journal of Astronomy and Space Sciences
• /
• v.20 no.2
• /
• pp.101-108
• /
• 2003

This study reports one approach for the classification of magnetic storms into recurrent patterns. A storm event is defined as a local minimum of Dst index. The analysis of Dst index for the period of year 1957 through year 2000 has demonstrated that a large portion of the storm events can be classified into a set of recurrent patterns. In our approach, the classification is performed by seeking a categorization that minimizes thermodynamic free energy which is defined as the sum of classification errors and entropy. The error is calculated as the squared sum of the value differences between events. The classification depends on the noise parameter T that represents the strength of the intrinsic error in the observation and classification process. The classification results would be applicable in space weather forecasting.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.788-791
• /
• 2006

The ion adsorption on an aligning layer deposited onto a conductive electrode in a liquid crystal (LC) cell has been shown to depend strongly on the dielectric constants of the layer and its thickness d. Calculations made in the framework of the three-layer electrostatic theory showed that, depending on those and other intrinsic parameter of the problems, it is possible to observe either ion attraction or repulsion at the aligning surface. Tentative measurements of the ion adsorption dynamics on the aligning layers with various d qualitatively agree with the theory. The results obtained allow the memory effect in LCs and the sticking effect in LC displays (LCDs) to be controlled effectively.

• Journal of Power System Engineering
• /
• v.19 no.3
• /
• pp.55-62
• /
• 2015

This paper discusses a new model for investigating the micro-mechanical behavior of beam-like structures composed of various elastic moduli and complex geometries varying through the cross-sectional directions and also periodically-repeated along the axial directions. The original three-dimensional problem is first formulated in an unified and compact intrinsic form using the concept of decomposition of the rotation tensor. Taking advantage of two smallness of the cross-sectional dimension-to-length parameter and the micro-to-macro heterogeneity and performing homogenization along dimensional reduction simultaneously, the variational asymptotic method is used to rigorously construct an effective zeroth-order beam model, which is similar a generalized Timoshenko one (the first-order shear deformation model) capable of capturing the transverse shear deformations, but still carries out the zeroth-order approximation which can maximize simplicity and promote efficiency. Two examples available in literature are used to demonstrate the consistence and efficiency of this new model, especially for the structures, in which the effects of transverse shear deformations are significant.

• Computers and Concrete
• /
• v.20 no.1
• /
• pp.23-29
• /
• 2017

In this study engineered steel fibres used as reinforcement for concrete were characterized by number of key mechanical and spatial parameters, which are easy to measure and quantify. Such commonly used parameters as length, diameter, fibre intrinsic efficiency ratio (FIER), hook geometry, tensile strength and ductility were considered. Effective classification of various fibres was demonstrated using simple multivariate computations involving principal component analysis (PCA). Contrary to univariate data mining approach, the proposed analysis can be efficiently adapted for fast, robust and direct classification of engineered steel fibres. The results have revealed that in case of particular spatial/geometrical conditions of steel fibres investigated the FIER parameter can be efficiently replaced by a simple aspect ratio. There is also a need of finding new parameters describing properties of steel fibre more precisely.

• Macromolecular Research
• /
• v.15 no.7
• /
• pp.605-609
• /
• 2007

The molecular interactions of polyacrylonitrile (PAN) and cellulose acetate (CA) were investigated thoroughly via dilute solution viscometry in dimethylformamide (DMF) as a common solvent at $30^{\circ}C$. The intrinsic viscosities and viscometric interaction parameters were experimentally determined for both binary (polymer/dimethylformamide) and ternary (PAN/CA/dimethylformamide) systems. As all investigated PAN/CA ternaries evidenced negative viscometric interaction parameter values $({\Delta}b\;&{\Delta}k<0)$, the existence of repulsive intermolecular interactions was deduced, and PAN/CA blends were assigned as immiscible. Moreover, the results of microscopy photograph analysis indicated that pure PAN film evidences a homophasic structure, and the size of the phase domain increases gradually with increases in CA. In DSC analysis, it was determined that the glass transition temperature of the blend film increased slightly with increases in the CA content of the blend film.