• Journal of Radiation Industry
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• v.6 no.3
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• pp.211-215
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• 2012

In this study, crosslinked polyethylene (PE) foam sheets were prepared through gamma-ray irradiation. PE foam sheets were prepared through a foaming process using sodium bicarbonate as a blowing and foaming agent. The prepared PE foam sheets were then crosslinked through gamma-ray irradiation. The crosslinking degree was increased to 86.0% with an increase in the absorption dose. The tensile strength of the crosslinked PE foam sheets was increased with an increase in the absorption dose. However, the elongation-at-break of the crosslinked PE foam sheets was decreased. The thermal decomposition temperature of the crosslinked PE foam sheets was increased to $421.2^{\circ}C$ with an increase in the absorption dose. The SEM analysis revealed that the morphology was not changed significantly after the crosslinking through gamma-ray irradiation.

• Journal of Adhesion and Interface
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• v.2 no.3
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• pp.9-15
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• 2001

To estimate the effect of the surface state of the EVA foam on an adhesion, the surface was treated with solvents having different values of a solubility parameter and a surface tension. The morphology and the contact angle were measured by SEM and contact angle tester, respectively. The value of the critical surface tension(${\gamma}_{c,0}$) of the EVA foam calculated by Zismann plot was 27.08 dyne/cm. The surface state and the ${\gamma}_c$ of the EVA foam were changed by solvent treatment. The swelling ratio of EVA foam was influenced by solubility parameter of a solvent, on the other hand the degree of change in the surface state was dependent on a surface tension of a solvent. When a surface tension of solvent. When a surface tension of solvent is lower than ${\gamma}_{c,0}$ of the EVA foam, the wettability of a solvent was good and the surface state was greatly changed. The adhesion strength of EVA foam was greatly improved to above 600% as compared to that of the untreated one. As the ${\gamma}_c$ of EVA was closed to the surface tension of the primer, the good adhesion strength was obtained.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.260-266
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• 2012

Syngas and hydrogen from the $CeO_2/ZrO_2$ coated foam devices were investigated under simulated solar radiation. The $CeO_2/ZrO_2$ coated SiC, Ni and Cu foam device were prepared using drop-coating method. Syngas production step was performed at $900^{\circ}C$, and hydrogen production process was performed for ten repeated cycles to compare the CeO2 conversion in syngas production step, $H_2$ yield in hydrogen production step and cycle reproducibility. The produced syngas had the $H_2$/CO ratio of 2, which was suitable for methanol synthesis or Fischer-Tropsch synthesis process. In addition, syngas and hydrogen production process is one of the promising chemical pathway for storage and transportation of solar heat by converting solar energy to chemical energy. After ten cycles of redox reaction, the $CeO_2/ZrO_2$ was analyzed using XRD pattern and SEM image in order to characterize the physical and chemical change of metal oxide at the high temperature.

• Polymer(Korea)
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• v.36 no.1
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• pp.34-40
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• 2012

The foaming of poly(butylene succinate) (PBS) using supercritical $CO_2(scCO_2)$ was studied. In order to improve the melt strength, PBS was modified using the reactive compounding technique. Rapid decompression of $scCO_2$-saturated PBS at a temperature above the depressed $T_m$ yielded expanded microcellular foams. The resulting foam structure could be controlled by manipulating process conditions. Experiments varying the foaming temperature while holding other variables constant showed that higher temperatures produced larger cells and reduced cell densities. Higher saturated pressures led to higher nucleation densities and smaller cell sizes. Decreasing the rate of depressurization permitted a longer period of cell growth and therefore larger cells were obtained.

• Journal of the Korean Society of Clothing and Textiles
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• v.9 no.3
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• pp.53-61
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• 1985

This paper has been studied on the method of washing without any damage on wool, namely foam washing method. Effect of washing was obtained with experimental equipment manufactured by way of trial. but some deflects were found that the volume of detergent solution and blow ratio changed with time passes by. This difficulties should be improved by farther studies. The solution mixed with sodium oleate ($0.5\%$) and sodium carbonate ($0.3\%$) was found suitable for detergent solution, and under the conditions of washing temperature at $50\~60^{\circ}C$ and washing time for 5 minutes, the washing effect was obtained good. Desoaping treatment with $Na_2CO_3$ solution after washing might be thought to be necessary, and from the scanning electron micrographs (SEM), no damage on wool and wool sureface washed was, observed. From the results of this study foam washing of wool may be expected to be very effective.

• KSBB Journal
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• v.26 no.1
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• pp.83-86
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• 2011

The stability of cream containing lotus leaf extract (LLE) was evaluated. Stability pH and viscosity were measured at 3 different temperatures ($25^{\circ}C$, $45^{\circ}C$ and $65^{\circ}C$), and at room temperature under the sun light at 2 day intervals during 12 days. The cleansing cream and foam cleansing containing the extract did not show a significant pH change at the different temperatures. However, the pH of the cleansing cream and foam cleansing containing LLE slightly decreased at $25^{\circ}C$. They showed a high stability at temperature conditions ($45^{\circ}C$ and $65^{\circ}C$) and under the sun light condition. The cleansing cream and foam cleansing containing LLE did not show a significant viscosity change at $25^{\circ}C$, but had a tendency of decrease at $45^{\circ}C$ and $65^{\circ}C$. There was no significant offflavor and discoloration as well as physical changes such as creaming and cohesion at $25-65^{\circ}C$ and under the sun light condition. And this LLE could be used as a stable functional cosmetic material.

• Horticultural Science & Technology
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• v.34 no.3
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• pp.414-423
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• 2016

Growers in plug seedling production think that root media in which rockwool is a component has given rise to several environmental problems. Therefore, the demand for new materials as a substitute for rockwool has been increased. This study examined the possibility of cultivation of tomato plug seedlings using a newly developed growing medium with phenolic foam. Plug seeds of tomato cultivar 'Madison' were sown in four pellet-type growing media: Grodan rockwool (GRW), UR rockwool (URW), phenolic foam LC (LC) or phenolic foam LC-lite (LC-lite). Then, the seedlings were transplanted to the four cube-type growing media 19 days after sowing. Seeds were germinated in a growth chamber ($25{\pm}2^{\circ}C$, 80% relative humidity, and dark) for 4 days and then the seedlings were grown with a nutrient solution supplied by an overhead irrigation system in a greenhouse. Plant height, number of leaves, leaf area, and fresh or dry weight of tomato seedlings were the greatest for the seedlings transplanted to URW cube media after being grown on LC-lite pellets. Root grade was the greatest for the seedlings transplanted on LC or LC-lite cube media after being grown on LC pellets. Chemical properties of all media tested for tomato growth were maintained within a stable range, while physical properties of URW showed high values in container capacity, air space, and total porosity. These results demonstrated that the phenolic foam media were effective for seedling growth and can substitute for rockwool as a root medium.

• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.307-311
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• 2014

This study investigated the effects of polyurethane foam on continuous hydrogen production from mixed wastes. Molasses was co-fermented with non-pretreated sewage sludge in a sequencing batch reactor. The results indicated that the addition of polyurethane foams as a microbial carrier in the reactor mitigated biomass loss at HRT 12 h, while most of the biomass was washed out during the operation period with no carrier. There was a stable hydrogen production rate of $0.4L-H_2/l/d$ in the carrier-sequencing batch reactor. Suspended biomass in the carrier-reactor indicated it possessed the highest specific hydrogen production rate ($241{\pm}4ml-H_2/g\;VSS/d$) when compared to that of biomass on the surface ($133{\pm}10ml-H_2/g\;VSS/d$) or inner carrier ($95{\pm}14ml-H_2/g\;VSS/d$).

• Fire Science and Engineering
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• v.29 no.3
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• pp.48-52
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• 2015

In this study, we have evaluated whether the mixing ratio is proper by creating a mixing device for foam proportioner that mainly is employed in practice utilizing a metering venturi type. In case of the mixing ratio for 3%, water under pressure of 76 mm in diameter and the original liquid of a foam fire extinguishing agent of 31.75 mm in diameter have showed up the fluctuation rate just as much as 3.1~3.5% of the mixing ratio. Because water under pressure of 101.6 mm in diameter and the original liquid of a foam fire extinguishing agent of 38.1 mm in diameter have showed up 3.3~3.7% of the fluctuation rate, water under pressure of 101.6 mm in diameter and the original liquid of a foam fire extinguishing agent of 38.1 mm in diameter have satisfied 3.0~3.9% of performance criterion. And also, in case of the 6% of mixture rate, water under pressure of 76.2 mm in diameter and the original liquid of a foam fire extinguishing agent of 31.75 mm in diameter have showed up the fluctuation rate just as much as 6.4~6.8% of the mixing ratio. Because water under pressure of 101.6 mm in diameter and the original liquid of a foam fire extinguishing agent of 38.1 mm in diameter have showed up 6.0~6.8% of the fluctuation rate, water under pressure of 101.6 mm in diameter and the original liquid of a foam fire extinguishing agent of 38.1 mm in diameter have satisfied 6.0~7.0% of performance criterion.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.337-345
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• 2009

This paper investigates the reliability of district heating pipes at thermo-elastic fatigue loading. District heating pipes, subjected to $120^{\circ}C$ and $16kg_f/cm^2$ due to water distributing service through inside the pipes, should endure long term cyclic thermal-mechanical loadings. The heating pipes are the co-centric tubes of steel pipe, poly urethane(PUR) insulator, and high density poly ethylene(HDPE) case. On installation, foam pad is externally wrapped for accommodating stress reduction near the bend sections of pipes. However, there have been frequent reports on the failures of bend sections in the middle of long term service. This study scrutinizes the observed failures near the bend sections through applying the finite element methods. Specially in this study, heating pipes are studied on the influence of foam padding on failures and proposed new designs for reinforced bend without foam pad.