• Korean Journal of Microbiology
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• v.53 no.4
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• pp.265-272
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• 2017

Some bacteria with different mechanisms for hydrocarbon degradation were isolated from oil-contaminated soils in Korea. Isolate Acinetobacter calcoaceticus SL1 showed biosurfactant- producing activity in oil-spreading test, and it exhibited a good emulsifying activity of 43.6 and 54.5% for diesel oil and n-hexane, respectively. It also has high cell surface hydrophobicity which can make it easily attaches to hydrocarbons and degrade them. It degraded 100% of 1,000 mg/L of n-octadecane and naphthalene, respectively in 3 days, 72.3% of 1,000 mg/L diesel oil in 7 days and 78.0% of 10,000 mg/L diesel oil in oil-contaminated soil during 28 days. Isolated strains Bacillus amyloliquefaciens S10 and B. subtilis GO9 can produce biosurfactant and formed 6.34 and 2.5 cm diameter of clear zones, respectively in oil-spreading test. Surface tension of their culture supernatant reduced from 74.6 to 34.4 and 33.3 mN/m, respectively during incubation, and critical micelle concentrations of culture supernatants were 2.0 and 5.9%, respectively. Consortium of A. calcoaceticus SL1 and B. amyloliquefaciens S10 degraded 77.8% of 10,000 mg/L diesel oil in 3 days, which indicated more efficient oil degradation than that by A. calcoaceticus SL1 alone. If these bacteria were applied together as a consortium to oil-contaminated sites, they may show a high removal rate of petroleum hydrocarbons.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.261-274
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• 2000

The o/w emulsions were prepared with saccharide surfactants which were sucrose monostearate(S160), sucrose distearate(S110), and POE(20) methyl glucose stearate(SSE20). And for emulsion the oils used were n-hydocarbon, squalane(SQ), liquid paraffin(LP), octylpalmitate(OP), octylstearate(OS), alkyl benzoate(AB), isostearyl benzoate(ISB). The structures of o/w emulsion droplet were investigated by laser light scattering and the fractal dimensions were calculated from light intensity curves. Increasing of concentration, chain length, and nonpolarity of oils, fractal dimensions of emulsion droplets were found greater. In general fiactal dimensions were varied from 1.7 to 2.8 and its structures were fractal But the fractal dimensions of octadecane( $C_{18}$), 50, and LP emulsified with S110 and S160 were varied from 3.0 to 3.2 and its structures were more dense. The overall fractal dimensions of S110 and S160 were varied from 2.1 to 2.6, that of SSE20 were varied from 1.5 to 2.1. So it was found that the structures of SSE20 system were less compact than that of S110 and S 160 system, because the hindrance effect of polyoxyehtylene group of SSE20 was stronger than that of sucrose of S160. The strucures of emulsion droplets changed according to the nature of emulsifiers and to compositions of oil substances which they contained, and the structures were found similar when the hydophilic moiety of emulsifiers was same.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.2
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• pp.1-7
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• 2015

As energy consumption of building and the reduction of carbon dioxide emissions have been emphasized, phase change materials(PCM) have been introduced as building materials due to its high heat storage performance. Using shape-stabilizing technique, octadecane/xGnP shape-stabilized PCM(SSPCM) can prevent leakage and improve heat storage performance. The objectives of this study are to propose mix design method of concrete mixed with SSPCM and to evaluate mechanical behaviors of the concrete mixed with SSPCM manufactured according to the proposed mix design. Based on the previously reported material test result, the existing mix design of plain concrete(Concrete standard specification, 2009) is modified to consider reduction of strength in concrete due to the addition of SSPCM. To verify the proposed mix design, specimens are fabricated according to the proposed mix design and axial strength tests and three-point loading tests are performed. Test results show that compressive strengths of the tested specimens reach the designed strength even when two different mix ratios of SSPCM are used. From three-point loading tests, flexural stresses decrease as mix ratio of SSPCM increases.

• Journal of Life Science
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• v.9 no.2
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• pp.76-81
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• 1999

216 microorganisms which able to degrade wasted lubricant were isolated in the region of contaminated with wated lubricant such automobile repair shops, garages and gas stations in Taejon. Most activated strain among them is selected and used in this research. The microorganism in identified as Acinetobacter lwoffii 16C-1, which shows active growth and hydrocargon utilization withnormal alkane such as tetradecane, hexadecane and octadecane, and do not grow aromatic hydrocargons, cycloalkane, and branched alkane. In addition, A. lwoffii 16C-1 has resistance to heavy metals such as Ba, Li, Cr, and Mn more than 6.4mg/ml, and showed negligible tolerance against antibiotics. Effects of environmental conditions including concentration of wasted lubricnt, pH, NaCl concentration, nitrogen source and phosphate on microorganism growth and emulsification were studied. 2% of wasted lubricant, pH 7.0, 0-1% of NaCl, 0.2% of peptone, and 0.01% of K2HPO4 is turn out to be optimum condition. By the analysis of remaining oils, almost of hydrocarbons added to the media are removed by A. lwoffii 16C-1 at 30$^{\circ}C$ after 2 days of culture, which showed excellent oil degradation characteristics.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.470-474
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• 2012

This paper deals with the thermal performances of PCM/diatomite composites for energy saving. The PCM/diatomite composites were prepared by incorporating PCMs in the pores of diatomite to increase form stability of PCMs. In experiment, we used the hexadecane, octadecane and paraffin as PCM and they have each 254.7 J/g, 247.6 J/g and 144.6 J/g of latent heat capacity, and those melting points are $20.84^{\circ}C$, $30.40^{\circ}C$ and $57.09^{\circ}C$, respectively. Thermal properties of PCM/diatomite composites were determined by using DSC. And PCM/diatomite composites were characterized by SEM and FTIR analysis. The results showed that the PCMs are well infiltrated into the structure of diatomite andt he latent heat capacity of PCM/diatomite composites was obtained by 40% of pure PCMs.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.2
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• pp.456-466
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• 1994

Experimental investigation was made to study the mechanism of fluid and thermal oscillation phenomena of surface-tension driven flow in a cylindrical liquid column heated from above which is the low-gravity floating zone simulated on earth. Hexadecane, octadecane, silicon oil (10cs), FC-40 and water are used as the test liquids. The onset of the oscillatory thermocapillary convection appears when Marangoni number exceeds its criteria value and is found to be due to the coupling among velocity and temperature field with the free surface deformation. The frequency of temperature oscillation decreases with increasing aspect ratio for a given diameter and Marangoni number and the oscillation level increases with Marangoni number. The flow pattern in the liquid column appears either as symmetric or asymmetric 3-D flow due to the oscillatory flow in the azimuthal direction. The free surface deformation also occurs either as symmetric or asymmetric mode and its frequency is consistent with those of flow and temperature oscillations. The amplitude of surface deformation also increases with Marangoni number.

• Journal of the Korean Solar Energy Society
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• v.35 no.1
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• pp.89-96
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• 2015

n-octadecnae based shape stabilized phase change material (SSPCM) was prepared by using vacuum impregnation method. And an exfoliated graphite nanoplate (xGnP) which has high thermal conductivity properties is used as a PCM container. And then we made heat storage concretes which contains SSPCM for reducing heating and cooling load in buildings. In the prepararion process, the SSPCM was mixed to a concrete as 10, 20 and 30wt% of cement weight. The thermal properties and chemical properties of heat storage concrete were analyzed from Scanning electron microscope (SEM), Fourier transformation infrared spectrophotometer (FT-IR), Deferential scanning calorimeter (DSC), Thermogravimetric analysis (TGA) and TCi thermal conductivity analyzer. And we conducted surface temperature analysis of SSPCM and xGnP by using heat plate and insulation mold.

• Journal of Adhesion and Interface
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• v.6 no.1
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• pp.11-18
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• 2005

The capsules were prepared from a phase change material (PCM) of octadecane as a core material and melamine formaldehyde resin as a shell material. The PCM capsule size was varied in the range of $3{\sim}25{\mu}m$. The core contents and sizes of the PCM capsule, were determined by DSC and SEM, respectively. An acrylic coating material which contains butyl acrylate (BA), methyl metacrylate (MMA) and acrylic acid (AA) were synthesized by emulsion polymerization. The films were prepared from the acrylic emulsion and PCM capsules which have various capsule sizes. From the results of SEM experiment, it was observed that the PCM capsules were well dispersed inside the film and the surface of the film became less rough when the PCM capsule size was small. The swelling ratio of the films were not significantly affected by the PCM capsule size. However, the tensile strength and elongation of the films were greatly decreased with increasing the PCM capsule size.

• Journal of Life Science
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• v.10 no.3
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• pp.300-306
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• 2000

Several bacterial strains utilizing crude oil as their sole carbon and energy source were isolated from polluted marine by crude oil. One of the strains, named KCL-2 showed strong degradation activity for crude oil. This strain was identified as a Klebsiella sp. based on the morphological, biochemical, and physiological characteristics. The optimum cultural conditions were as follows; $27^{\circ}C$~$37^{\circ}C$ for temperature and 7.0 for initial pH. Additionally, the optimal concentration of sodium chloride was 3.0%, confirming indicating that this strain was derived from sea water.The strain KCL-2 could use several kinds of n-alkane hydrocarbones from octadecane to octacosane as a sole carbon source. The emulsifying activity by KCL-2 was the highest after 3 days of cultivation under the condition of 3.0% sodium chloride, pH 7.0 and 32$^{\circ}C$. This strain had several criptic plasmids.

• KSBB Journal
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• v.26 no.1
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• pp.49-56
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• 2011

Volatile components of crude fucoidan and its raw material, Undaria pinnatifida sporophylls were identified by GC/MSD analysis, and the effects of a combined method of solvent extraction and drying (hot-air drying or spray drying) on deordorization of fucoidans were examined. The major components of seaweed smell (odor) in crude fucoidan and Undaria pinnatifida sporophylls were identified as alkanes (octadecane, heptadecane, tetradecane) and acids (hexadecanoic acid, oleic acid). Solvent extraction and drying were combined for the deordorization of fucoidans: hot-air drying/deordorization process (HDDP) and spray drying/deordorization process (SDDP). The deordorization effects of solvent extraction using solvents including water, ethanol, and acetone were investigated. Among the tested solvents, ethanol was selected as a deordorization solvent, because the seaweed smell and taste were mostly lowered by ethanol extraction followed by drying. In addition, HDDP and SDDP were compared, showing that SDDP gave higher sensory characteristics than HDDP. When the crude fucoidan was treated by ethanol extraction for 30 min followed by SDDP, approximately 60% of off-flavor components of crude fucoidan was removed based on GC/MSD peak area, and the total sugar and sulfate contents and APTT-anticoagulant activity significantly increased compared to crude fucoidan. In conclusion, SDDP after ethanol treatment was proposed and established as a deordorization process for fucoidan preparation.