• Journal of Advanced Marine Engineering and Technology
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• 제28권3호
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• pp.451-456
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• 2004

This present experimental study has dealt with the heat transfer characteristics of plastic particle slurry which flows in a circular tube. This type of slurry is suggested for heat transfer enhancement effect cause by random and vortex effect of plastic particle dispersed in water. As a result, the thermal boundary layer becomes thin so the heat transfer coefficient on the tube wall more increase compare to pure water flow. This experimental test section was composed with stainless pipe which has the length of 2000mm, inner pipe diameter of 14mm and outer pipe diameter of 60mm. The most effective and important parameter of this experiment is plastic packing factor(PPF). The focuses of these results are pressure drop and heat transfer coefficient. As results, the friction factor of plastic particle slurry becomes higher at laminar flow region than pure water because of buoyancy effect of plastic particle but the local heat transfer coefficient becomes higher.

• 산업기술연구
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• 제24권A호
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• pp.251-261
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• 2004

A series of column test with a silty marine soil mixed with Jumunjin Standard Sand were performed to investigate the characteristics of settling and consolidation of non-plastic dredged soils. Column tests were carried out by using the separable column to measure the grain size distribution of consolidated layer. Column tests were performed with changing the mixing ratio of Jumunjin Standard Sand to the silty marine soil, initial water content of slurry and initial height of slurry. Height of interface of slurry was monitored during tests and grain size distribution tests were carried out after finishing tests. Influencing factors on the particle segregation, eventually to the characteristics of settling and consolidation of non-plastic soil, were analyzed on the thesis of test results. As results of column tests, the mixing ratio of sand to the silty marine soil and the initial water content of slurry were known to affect the characteristics of settling and consolidation resulted in significant particle segregation of slurry. Initial height of slurry was found not to affect seriously to particle segregation.

• 정보저장시스템학회논문집
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• 제7권2호
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• pp.60-64
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• 2011

Chemical mechanical planarization is one of the core processes in fabrication of semiconductors, which are increasingly used for information storage devices like solid state drives. For higher data capacity in storage devices, CMP process is required to show ultimate precision and accuracy. In this work, 2-dimensional finite element models were developed to investigate the effects of the slurry particle impact on microscratch generation and the phenomena generated at pad-particle-wafer contact interface. The results revealed that no plastic deformation and corresponding material removal could be generated by simple impact of slurry particles under real CMP conditions. From the results of finite element simulations, it could be concluded that the pad-particle mixture formed in CMP process would be one of major factors leading to microscratch generation.

• Journal of the Korean Wood Science and Technology
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• 제22권1호
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• pp.85-90
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• 1994

The flow properties of binder latices for paper coating were investigated, together with dynamic viscoelastic properties of latex films and electron micrographs of latices, under various conditions. The amphoteric latex, binder pigment latex and anionic latex were used in this work. The amphoteric latex has both anionic and cationic functional group on its surface. The binder-pigment with a core-shell structure has dual functions : plastic pigment and binder. The low shear viscosity of binder latices and clay slurry were measured with Brookfield vis cometer. At low-shear rates. the viscosity decreased with increasing particle size of latex. On the amphoteric latex surface, the carboxyl groups are assumed to be fully dissociated over the region of pH 9~12, but the density of negative groups seems to be increased because of the gradual decrease in the degree of dissociation of amino groups. Since the apparent particle size of latex increases with surface charge, the electroviscous effect can be observed. On the anionic latex surface, the charge density is assumed to be nearly constant above pH 8. However, below pH 8 the coagulation of particles could be observed probably because of the decrease in the charge density.

• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.21-30
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• 2015

Ceramic foams are prepared as positive images corresponding to a plastic foam structure which exhibits high porosities (85-90%). This structure makes the ceramic foams attractive as a catalyst in a dry reforming process, because it could reduce a high pressure drop problem. This problem causes low mass and heat transfers in the process. Furthermore, the reactants would shortly contact to catalyst surface, thus low conversion could occur. Therefore, this research addressed the preparation of dry reforming catalysts using a sol-gel catalyst preparation via a polymeric sponge method. The specific objectives of this work are to investigate the effects of polymer foam structure (such as porosity, pore sizes, and cell characteristics) on a catalyst performance and to observe the influences of catalyst preparation parameters to yield a replica of the original structure of polymeric foam. To accomplish these objectives industrial waste foams, polyurethane (PU) and polyvinyl alcohol (PVA) foams, were used as a polymeric template. Results indicated that the porosity of the polyurethane and polyvinyl alcohol foams were about 99% and 97%. Their average cell sizes were approximate 200 and 50 micrometres, respectively. The cell characteristics of polymer foams exhibited the character of a high permeability material that can be able to dip with ceramic slurry, which was synthesized with various viscosities, during a catalyst preparation step. Next, morphology of ceramic foams was explored using scanning electron microscopy (SEM), and catalyst properties, such as; temperature profile of catalyst reduction, metal dispersion, and surface area, were also characterized by $H_2-TPR$ and $H_2-TPD$ techniques, and BET, respectively. From the results, it was found that metal-particle dispersion was relatively high about 5.89%, whereas the surface area of ceramic foam catalysts was $64.52m^2/g$. Finally, the catalytic behaviour toward hydrogen production through the dry reforming of methane using a fixed-bed reactor was evaluated under certain operating conditions. The approaches from this research provide a direction for further improvement of marketable environmental friendly catalyst production.