• Journal of Korea Foundry Society
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• v.27 no.1
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• pp.36-41
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• 2007

Compressive properties of the open cell 6063 aluminum alloy foams made by the plaster molding process were investigated before and after heat treatment. Loading process was controlled at a displacement rate of 2 mm/min. Compressive strength of 10 PPI foam was the largest of the same density foams. Increase in strength after heat treatment for the bulk material was remark able, however was not for the 6063 aluminum foam. C values were in the range of $0.39{\sim}0.53$ for as cast foams and $0.13{\sim}0.16$ for T6 heat treated foams in the equation of ${sigma}^*_{pl}/{\sigma}_{ys}=C({\rho}/{\rho}_{s})^{1.5}$ and increased with cell size.

• Polymer(Korea)
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• v.34 no.1
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• pp.8-13
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• 2010

The physical properties of polymeric foams depend on the density of foams, physical properties of base polymers, the content of open cells, and cell structures including the size and its distribution, the shape of cell, and the thickness of skin layer. The foam density is affected by the chemistry of raw materials, the concentration of crosslinking agent and the blowing agent as well as the operating parameters during production process. In this study, the basic formulations of foams are composed of polyester polyol, MDI, amine catalyst, tin catalyst, silicone surfactant, and water. Cross-linking density of polyurethane was increased by using chain extenders. Also, the mechanical properties of polyurethane foam were improved by using the inorganic fillers (silica 1,2 and talc 1,2) having different $SiO_2$ contents and particle sizes. We investigated the properties of modulus, tensile strength, compressive strength and hardness of foams obtained by changing kind of inorganic filler and chain extender, and observed the distribution of inorganic filler as well as variation of cell size within the foams by electron microscopy.

• Composites Research
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• v.23 no.3
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• pp.64-68
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• 2010

Expanded polystyrene(EPS) foams are often used in packaging to protect electrical appliances from impact loads. The energy absorbing performances of the EPS foams depend on several parameters such as density, microstructure and strain rate. Thus, the effects of the parameters on the strength of the EPS foams need to be investigated for an optimized packaging design by FEM. In this study, various EPS foams which have different densities were quasi-statically and dynamically loaded in order to obtain the stress-strain curves. EPS foams of various densities from 18.5 to 37.0kg/m3 were considered in the experiments. A drop-mass type apparatus was developed for the intermediate strain rate tests up to several hundreds/second. It was found from the experimental results that the strength of the EPS foams increase about 170% as the strain rate increases from 0.06/s to 60/s. Experimental results also showed that the strain rate sensitivity increases as the strain increases.

• Korean journal of food and cookery science
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• v.8 no.2
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• pp.83-93
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• 1992

This dissertation was aimed to study the stability of egg foams and the quality of rice yackwa added with egg foams. Because of the difference of protein composion between rice flour and wheat flour, yackwa made from rice powder turned out to be harder and less raised. Egg foams were added to the rice flour to help raise the dough to a great extent and make it softer when frying. The smaples were prepared differently: in the finess of rice flour (100, 140 mesh), the kinds of egg foams (whole egg, egg white), and the content of egg foams (40 g, 60 g), respectively. The stability of egg foams was determined by an Optical microscope, the hardness of rice yackwa was examined by Instron, the structure by Scanning Electron Microscope, the color by Hunter's Colorimeter, and the sensory evaluation was also made. The resluts are as knows: The most stable egg white foam and whole egg foam were the 2 and 3 min. whipped ones, respectively. In the case of rice yackwa, which was made from 140 mesh rice flour and 60 g of whole egg, the hardness and the structure were similar to those of wheat yackm. It was very tasty and most preferred. As a whole, the color of rice yackwa was lighter man mat of wheat yackwa.

• Elastomers and Composites
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• v.39 no.2
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• pp.105-120
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• 2004

The flame retarded NBR foams were prepared with metal hydroxides and various phosphorus/nitrogen-contain ing flame retardants. The dependency of the phosphorus content on thermal properties, flame retardancy, smoke density, and foaming properties were investigated in the foams. Foaming properties and morphology of the flame retarded NBR foams with P/N flame retardants( ${\le}10 phr$) were similar to those of the foams without P/N ones but containing metal hydroxides The flame retardancy of the foams was improved with increasing the phosphorus content and char formation under combustion atmosphere. The cone-calorimeter test and LOI index were also coincided with the TGA analysis quite well. The heat release rate (HRR), total heat release (THR), and effective heat of combustion (EHC) were decreased, whereas the carbon monoxide yield was increased with increase of the phosphorus content of P/N flame retardant. The smoke density values were closely related with CO yield values obtained by the cone-calorimeter test due to the high and hard char formation.

• Journal of Adhesion and Interface
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• v.19 no.2
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• pp.68-73
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• 2018

In this study, conductive EVA foams including multi-wall carbon nanotubes (MWCNT), glass beads were prepared. The electrical conductivity and physical properties of the foams were confirmed with varying amount of MWCNT, mixing time, and amount of glass beads. The electrical conductivity increased with the amount of MWCNT. Dispersity of MWCNT in EVA foams were improved with glass beads. It can be suggested that conductive EVA foams can be successfully prepared with improved dispersity of MWCNT in ethylene-vinyl acetate by using glass beads.

• International Journal of Advanced Culture Technology
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• v.3 no.1
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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.

• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.30-35
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• 2020

In this study, polyurethane-silica composite foams were synthesized to analyze thermal insulation characteristics and mechanical properties. In order to synthesize polyurethane-silica composite foams, polyester-silica composite polyols were first synthesized via a polymerization reaction with silica sol, dicarboxylic acid and glycol in monomer state. Physical properties of polyurethane-silica composite foams synthesized using the composite polyols were analyzed. From the thermal conductivity analysis, no significant differences among HPUF0, HPUF1, HPUF3 and HPUF5 were found. The compressive strength of polyurethane-silica composite foams increased as the silica content increased. The mechanical property of HPUF5 was also about 25% higher than that of HPUF0.

• Korean journal of food and cookery science
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• v.20 no.4
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• pp.387-395
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• 2004

The effect of commercial Doenjangs (Korean soybean pastes) on sponge cake making was studied. When Doenjang was added to e99 foams at levels of 5, 10, 15 and 20%, there were no big differences in viscosity or stability of egg foams up to 15%, and thus in cake volume index, compared to those of control (without Doenjang). In the results of preference rank test, cake with 10% Doenjang was preferred to the other cakes. Therefore, it was decided that the addition of 10% Doenjang was suitable for sponge cake making. When seven commercial Doenjang products were used at 10%, there were differences in physical and sensory properties. The decreased viscosity of egg foams reduced their stability and so decreased the quality of the sponge cakes with low volume index and low texture scores. The use of Doenjangs improved the flavor of sponge cake and so countervailed the undesirable egg flavor. Especially, “C” Doenjang product, which increased the viscosity and stability of egg foams, produced good foaming ability and the highest physical and sensory quality, thus the higher overall acceptable scores than the control. It was probably due to its high amount of protein hydrolysate above 10-KDa. Consequently, the suitable amount of Doenjang was fixed at 10% and “C” Doenjang product was chosen as the best among the commercial products for sponge cake making.

• Polymer(Korea)
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• v.30 no.5
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• pp.402-406
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• 2006

New antibacterial Polyurethane foams for car seat with Urushiol extracted from a natural lacquer were prepared. Influences of antibacterial agent's concentration on the reactivity with isocyanate and the mechanical properties of foams were investigated. It was observed that the urethane formation reaction was delayed a little when the amount of Urushiol was increased. However, the foams made using Urushiol showed similar property to the neat polyurethane foam. In terms of antibacterial property, the foams prepared with Urushiol showed better performance than the neat polyurethane foam.