• Fibers and Polymers
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• 제7권2호
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• pp.164-168
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• 2006

Three vat dyes have been applied to regular viscose rayon and their dyeing and wash fastness properties were evaluated. Particle size determination was undertaken to obtain information about the size of dye particles converted by a reducing agent, to see if dye particle size has an affect on dyeing properties of regular viscose rayon. It is observed that viscose rayon exhibits more dyeability with reducing agent concentrations between 5-7.5 g/l. Also, we found that the vat dyeing system is greatly affected by the particle size of the vat dye converted to leuco form by a reducing agent.

• 한국구조물진단유지관리공학회 논문집
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• 제9권1호
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• pp.225-232
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• 2005

본 연구는 인장력을 받는 인장이음의 응력분포 및 인장파괴거동의 결과를 제시하였다. 본 연구에서 이음부의 볼트 배열방식은 정열배치와 엇모배치를 사용하였다. 실험값의 검증을 위해서 유한요소 해석을 실시하여 응력분포패턴을 파악하였다. 인장실험을 통해서 이음재의 항복 및 최대인장응력, 응력의 분포비, 유효단면적의 검토를 비교하여 차이점을 분석하여 보았다.

• Wind and Structures
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• 제24권2호
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• pp.95-118
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• 2017

The present study revealed comparison the pressure distribution on the surfaces of regular cross plan shaped building with angular cross plan shaped building which is being transformed from basic cross plan shaped building through the variation of internal angles between limbs by $15^{\circ}$ for various wind incidence angle from $0^{\circ}$ to $180^{\circ}$ at an interval of $30^{\circ}$. In order to maintain the area same the limbs sizes are slightly increased accordingly. Numerical analysis has been carried out to generate similar nature of flow condition as per IS: 875 (Part -III):1987 (a mean wind velocity of 10 m/s) by using computational fluid dynamics (CFD) with help of ANSYS CFX ($k-{\varepsilon}$ model). The variation of mean pressure coefficients, pressure distribution over the surface, flow pattern and force coefficient are evaluated for each cases and represented graphically to understand extent of nonconformities due to such angular modifications in plan. Finally regular cross shaped building results are compared with wind tunnel results obtained from similar '+' shaped building study with similar flow condition. Reduction in along wind force coefficients for angular crossed shaped building, observed for various skew angles leads to develop lesser along wind force on building compared to regular crossed shaped building and square plan shaped building. Interference effect within the internal faces are observed in particular faces of building for both cases, considerably. Significant deviation is noticed in wind induced responses for angular cross building compared to regular cross shaped building for different direction wind flow.

• 대한치과보철학회지
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• 제35권1호
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• pp.144-164
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• 1997

The purpose of this study were to investigate the chemical composition, mean particle size, linear thermal expansion coefficient and metal-bonding strength of the regular opaque powder and core powder. In this study, 4 types of ceramic powders, namely Duceram Jacket Opaque powder, Duceram Opaque powder, Vita Hi-Ceram powder, Vita VMK Paint On-88 powder were used. Chemical composition was evaluated by EDS(Energy Dispersive X-ray Spectrophotometer, Oxford QX-2000, England), particle size was measured by MALVERN Instruments(MALVERN Instruments SB. OC., U.S.A.. ad linear thermal expansion coefficient was measured by dilatometer(Motoyama, Japan). Bond strength was measured by the Universal tsting machine(Istron Co., Ltd., U.S.A.). The Results were as follows : 1. Through recognition of the relative difference in chemical composition between the core powder and the regular opaque powder, the difference in the proportion of $Al_2O_3$ in each type of material is demonstrated ; Duceram Jaket Opaque powder : 30.16%, Duceram Opaque powder : 16.60%, Vita Hi-Ceram : 63.64%, Vita VMK Paint-On 88 : 16.16%. 2. There was no significant difference in the proportion of metal-bonding materials between the core powder and the regular opaque powder. 3. In the regular opaque powder, alkaline materials were incoporated in order to increase the coefficient of thermal expansion. 4. In the particle size analysis, there was no significant difference in mean particle size or in the particle size distribution between the core powder and the regular opaque powder. 5. In the thermal expansion test for temperature range of $25-600^{\circ}C$, the regular opaque powder had higher coefficient of thermal expansion than that of core powder. 6. In the 4 point flexural bending test, there was no statistically significant difference in the mean bond strength between the core powder and the opaque powder among the Duceram products.

• Journal of Advanced Research in Ocean Engineering
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• 제3권4호
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• pp.174-183
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• 2017

Numerical simulations were performed about the green water problem of a FPSO. Three regular waves in head sea were tested. A rectangular box-shaped FPSO was considered and it is assumed there is a vertical wall on the deck. For the numerical simulations, an open-source CFD code, OpenFOAM, was applied to solve the present problems. Focus is on wave fields around the FPSO, water flows and impact pressures on the deck. For the validation, the present calculation results were compared with the existing experimental of Lee et al. (2012) and Changwon university in KTTC Cooperative Study Report (2015). The statistical values and spatial distribution of the peak pressures are directly compared with the experimental data. Some discussions are made on the effects of the domain breadth on the Green water impact pressure.

• Macromolecular Research
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• 제10권1호
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• pp.44-48
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• 2002

The supermolecular structures of poly(ethylene terephthalate) (PET), poly(ethylene 2,6-naphthalate) (PEN), and their blend were investigated with optical microscopy and small angle light scattering. With increasing the crystallization temperature, incomplete spherulitic texture was developed for the PET samples. At a high crystallization temperature of 220 $^{\circ}C$, the light scattering pattern represented a random collection of uncorrelated lamellae. The general morphological appearances for the PEN samples were similar to that of the PET. A notable feature was that the spherulites of the PEN formed at 200 $^{\circ}C$ showed regular concentric bands arising from a regular twist in the radiating lamellae. The spherulitic morphology of the PET/PEN blend was largely influenced by the changes of the sequence distribution in polymer chains determined by the level of transesterifcation. The increased sequential irregularity in the polymer chains via transesterification caused a morphological transition from a regular folded crystallite to a tilted lamellar crystallite.

• 산업경영시스템학회지
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• 제31권4호
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• pp.41-48
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• 2008

The purpose of this study was to investigate the job stress factors that were related to the general characteristics, work characteristics, and health characteristics of the workers at distribution industry. The survey of job stress measurement scale for Korean employee which was developed by KOSHA and OSHRI in 2003 was used for this study. Three hundred and fifty workers at distribution industry participated in this study, and among them 326 responses were analyzed for this study due to the unreliability and insincerity of responses. Eight job stress factors like physical environment, self-control for the job, job unsecure, organization system, workplace culture, compensation for the job, relationship to the superior, and job requirement were analyzed. The results showed that the stress because of self control for the job was relatively higher than that of other industry workers. However, the stress because of physical environment, job requirement, job unsecure, organization system and compensation for the job was relatively lower than that of other industry workers. The female workers felt more stress than male workers in compensation for the job and workplace culture factors at distribution industry. The delivery and carrying job workers were more stressful than those of other jobs at distribution industry because of physical environments and self-control for the job. The non-regular job workers were more stressful than regular job workers in many stress factors like self-control for the job, job unsecure, organization system and compensation for the job.

• 한국언어정보학회지:언어와정보
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• 제14권1호
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• pp.145-163
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• 2010

This paper aims to propose that Benford's Law, non-uniform distribution of the leading digits in lists of numbers from many real-life sources, also appears in linguistic texts. The first digits in the frequency lists of morphemes from Sejong Morphologically Analyzed Corpora represent non-uniform distribution following Benford's Law, but showing complexity of numerical sources from complex systems like earthquakes. Benford's Law in texts is a principle reflecting regular distribution of low-frequency linguistic types, called LNRE(large number of rare events), and governing texts, corpora, or sample texts relatively independent of text sizes and the number of types. Although texts share a similar distribution pattern by Benford's Law, we can investigate non-uniform distribution slightly varied from text to text that provides useful applications to evaluate randomness of texts distribution focused on low-frequency types.

• 한국항만학회지
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• 제12권2호
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• pp.251-260
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• 1998

For the purpose of building the simulation model on cargo handling capacity in container terminal we composed a model of container logistics system which has a 4 subsystem; cargo handling transportation storage and gate complex system. Several data are used in simulation which were gained through a field study and a basic statistic analysis of raw data on BCTOC from January to Jane in 1998. The results of this study are as follows; First average available ratios of each subsystems were 50% for G/C, 57.5% for Y/T, 56% for storage system and 50% for gate complex. And there were no subsystems occurring specific bottleneck. Second comparing the results of simulation to the results of basic statistics analysis we can verifying the suitability of this simulation model. Third comparing the results of this study to the results of existed similar study in 1996, we were able to confirm the changes of container logistics system in BCTOC.

• Earthquakes and Structures
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• 제11권1호
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• pp.25-43
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• 2016

The uneven distribution of rolling friction coefficient may lead to great uncertainty in the structural seismic isolation performance. This paper attempts to improve the isolation performance of a spring-damper-rolling isolation system by artificially making the uneven friction distribution to be concave. The rolling friction coefficient gradually increases when the isolator rolls away from the original position during an earthquake. After the spring-damper-rolling isolation system under different ground motions was calculated by a numerical analysis method, the system obtained more regular results than that of random uneven friction distributions. Results shows that the concave friction distribution can not only dissipate the earthquake energy, but also change the structural natural period. These functions improve the seismic isolation efficiency of the spring-damper-rolling isolation system in comparison with the random uneven distribution of rolling friction coefficient, and always lead to a relatively acceptable isolation state even if the actual earthquake significantly differs from the design earthquake.