• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.1
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• pp.25-31
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• 2009

Supercooled type ice storage system with aqueous solution (or water) may have trouble with non-uniform release of supercooling even though it contributes to the simplicity of system and ecological improvement. The non-uniform release increases the instability of the system because it may cause an ice blockage in pipe or cooling part. In order to suppress the release of the supercooling, a cooling experiment was tried to an ethylene glycol(EG) 3 mass% solution corresponding with pressurization. Also, the frequency ratio of the release of the supercooling was measured to the pressurization from 101 to 505 kPa. At results, the frequency ratio of supercooling release tends to decrease as the pressure of the aqueous solution increased in each cooling rate. Moreover, it tends to decrease as the cooling rate of the solution decreased in each pressure.

• Journal of the Korean Chemical Society
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• v.15 no.6
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• pp.293-303
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• 1971

The theological properties of aqueous suspensions of Black Hills bentonite were measured by using a Couette-type viscometer. Three kinds of flow units in aqueous bentonite suspension were postulated. Each has a different average relaxation time, one Newtonian. One of the non-Newtonian types is thixotropic, and the other is non-thixotropic. The thixotropic non-Newtonian unit is transformed to a Newtonian unit by shear stress. If the stress is relieved, the transformed unit returns to its original state. Two flow equations were derived by introducing chemical kinetics consideration for such a transition into the generalized theory of viscous flow. One equation describes the "upcurve," a diagram of rate of sheat versus shear stress, obtained by increasing the rate of shear, and the other relates to the "downcurve" obtained by decreasing the shear rate. The equations satisfactorilly describe the experimental thixotropic hysteresis of bentonite suspensions. The equations also were successfully applied to the flow curves of the suspensions containing various amounts of monovalent electrolyte (KCI).

• Journal of the Korean Applied Science and Technology
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• v.16 no.3
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• pp.237-240
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• 1999

This study showed that the optimized cleaning process using non-aqueous cleaning solvents is adaptable in the industrial field for existing 1.1.1-TCE cleaning solvents which is an ozone depleting sustance. Alternative cleaning solvent system substituted for existing cleaning solvent against non-aqueous pollutants(cutting & flux oil), was evaluated for the cleaning efficiency using gravimetric analysis method and surface change of sample by Image analyzer. The results showed that alternative solvents and process had excellent cleaning efficiency.

• Textile Coloration and Finishing
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• v.15 no.5
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• pp.327-332
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• 2003

In this study, the polyurethane microcapsules for non-aqueous dyeing containing iron oxide and disperse dyes were prepared by in-situ polymerization method using hexamethylene diisocyanate(HDI) with ethylene glycol(EG). And the size, shape, and particle size distribution of microcapsules prepared were investigated. The size and shape of microcapsule were observed by optical microscope and scanning elecron microscope. The particle size distribution was analyzed by particle size analyzer. The microcapsule size and its distribution were largely effected by the existance of surface active agent in the system. When a surfactant did not exist in the system, the size distribution of microcapsules prepared was much uneven. By adding a surfactant, this phenomenon was disappeared. And the size of microcapsule was also effeced by the hydrophobicity of core material(disperse dye). It was considered due to the difference of dispersity of core materials. And the size of microcapsule prepared was inversely proportional to the stirring speed.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3183-3189
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• 2010

In order to increase the specific capacitance and energy density of supercapacitors, non-aqueous supercapacitors were prepared using lithium transition-metal oxides and activated carbons as active materials. The electrochemical properties were analyzed in terms of the content of lithium transition-metal oxides. The results of cyclic voltammetry and AC-impedance analyses showed that the pseudocapacitance may stem from the synergistic contributions of capacitive and faradic effects; the former is due to the electric double layer which is prepared in the interface of activated carbon and organic electrolyte, and the latter is due to the intercalation of lithium ($Li^+$) ions. The specific capacitance and energy density of a supercapacitor improved as the lithium transition-metal oxides content increased, showing 60% increase compared to those of supercapacitor using a pure activated carbon positive electrode.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.38-44
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• 2002

Dispersion stability of nano-sized rutile TiO$_2$powder with acicular typed primary particle produced by homogeneous precipitation process at low temperatures was studied in aqueous and non-aqueous media in the presence of various electrolytes. The zeta potential measurements have shown that the addition of electrolytes to aqueous and non-aqueous dispersion media leads to charge reversal on TiO$_2$particle surface. The electrostatic repulsive forces acting on between TiO$_2$particles dispersed in non-aqueous media were found to be significantly greater than that in aqueous media, which relate closely to the physical properties of the organic solvents, such as viscosities and dielectric constants. The pH values, the concentration of electrolytes and the valence of the ions have changed greatly the surface potential of TiO$_2$ particles and have governed the dispersion behavior of TiO$_2$particles virtually.

• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.51-61
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• 1997

The objective of this study is to evaluate the feasibility of Pumping-and-Treatment system (PTS) for remediation of the saturated zones contaminated with NAPLs. A simulation is carried out for the removal of DNAPLs (denser-than-water non-aqueous phase liquids) and LNAPLS (lighter-than-water non-aqueous phase liquids) distributing at and below the water table. In the study, LNAPL and DNAPL are assumed to be n-hexane and 1,1-dichloroacetone, respectively. The model system studied consists of four heterogeneous soil layers with different permeabilities. Groundwater flows through the bottom layer and a pumping well is located under the initial water table. The time-driven deformation of the water table and removal efficiency of contaminants are estimated after vacuum application to the inlet of the well. In the calculation, FVM (Finite Volumetric Method) with SIMPLEC algorithm is applied. Results show that removal efficiencies of both DNAPL and LNAPL are negligible for the first 5 days after the PTS operation. However, when the cone-shape water table is formed around the inlet of the pumping well, the rapid removal rate is obtained since NAPLs migrate rapidly through the curvature of the water table. The removal efficiency of DNAPL is estimated to be higher than that of LNAPL due to the gravity. The results also show that the fluctuation or cone-shaped depression of the water table enhances the removal efficiency of NAPLs in saturated zones. The simulation results could provide a basis of the PTS design for the removal of NAPLs in saturated zones.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.2
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• pp.19-27
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• 2001

In the present study, the effects of film Reynolds number (60∼200) and volumetric content of non-absorbable gases (0∼10%) in water vapor on the absorption process of aqueous LiBr solution were investigated experimentally. The formation of solution film on the horizontal tubes of six rows was observed to be complete for Re>100. Transition film Reynolds number was found to exist above which the Nusselt number and Schmidt number diminishes with solution flow rate. As the concentration of non-absorbable gases increased, mass transfer rate decreased more seriously than heat transfer rate did. the degradation effects of non-absorbable gases seemed to be significant especially when small amount of non-absorbable gases was introduced to the pure water vapor.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.247-249
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• 2002

The transfer behaviors of three Polyarmatic hydrocarbons (PAHs) from soil to non-aqueous phase liquid (NAPL) were investigated. The three different PAHs were phenanthrene, anthracene, and pyrene. The used NAPLs were silicone oil and paraffine oil. The percentage of the remained PAHs into soil were similar without the relation to kinds of NAPLs. And the transfer of PAHs into NAPLs was fastened until 1 day as the increase of mixing rate but in the case of 450 rpm, the remained PAHs into soil was increased after 1 day because NAPLs was emulsified.

• The Plant Pathology Journal
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• v.17 no.5
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• pp.264-270
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• 2001

The effects of leaf extracts of 14 different non-host plant species on in vitro conidial germination of Phaeoisariopsis personata, the causal organism of late leaf spot(LLS) of groundnut were evaluated. Aqueous and ethanol leaf extracts of Datura metel, Lawsonia inermis and aqueous leaf extracts of Sphaeranthus indicus at 25%(w/v) concentration completely inhibited the conidial germination of P. personata both at 24h and 48h after incubation. Aqueous leaf extracts of Blumea bifoliata, Eucalyptus globules, Ocimum sanctum and Pongamia pinnata, and ethanol leaf extracts of Azadirachta indica and S. indicus inhibited the conidial germination by >90%. Aqueous and ethanol leaf extract of L. inermis and S. indicus were highly inhibitory to conidial germination up to 1% concentration. Aqueous and ethanol leaf extracts of D. metel and ethanol leaf extract of A. indica were highly inhibitory to P. personata even at 0.01% (100 ppm) concentration. Ethanol leaf extract of A. indica up to $80^{\circ}$, aqueous leaf extracts of D. metel and S. indicus up to $100^{\circ}$, and L. inermis up to $60^{\circ}$, were highly stable and retained their fungitoxic effects. Extract of D. metel was antifungal even after 180 days when it was stored both at room temperature and $4^{\circ}$. Aqueous leaf extract of D. metel at 2% concentration effectively reduced the development of LLS by >60%, under greenhouse conditions both in prophylactic and simultaneous applications. Extracts of D. metel could be a potential economical and an eco-frendly alternative for control of late leaf spot, and its efficacy under field conditions is further being evaluated.