• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.9
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• pp.895-903
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• 2001

Evaporation cooling phenomena of droplets containing fire suppression agents on a hot metal surface were experimentally investigated. Solution of water containing potassium acetate (30-50% by weight) and sodium bromide (10-30% by weight) were used in the experiments, and surface temperatures were ranged from 70-116$^{\circ}C$. The evaporation time of the droplet on the heated surface was determined by using frame-by-frame analysis of the video records. It is found that the apparent evaporation time is shorter in turns of pure water, sodium bromide solution and potassium acetate solution. However, the time averaged heat flux is higher in turns of pure water, sodium bromide solution and potassium acetate solution. In-depth temperature variation of the hot metal does not occur significantly by the kinds of additive.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.4
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• pp.418-429
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• 1992

Recently, many researchers make a great effort to develop high efficient marine diesel engines using low grade heavy oil, and also study substitution fuel oil for engines and boilers. In case of Fisheries Vessels, we need to know that fish oil can be substituted for fuel oil. Therefore, it is studied that evaporation, ignition and combustion phenomena of the single droplet of fish oils (i.e., Sardine fish oil, File fish oil and Alaska pollac oil) on heated plane surface to evaluate appropriateness as substitution oil. Methanol and light oil are tested simultaneously to help the evaluation on these Fish oils. The results are summarized as follows: 1. The type of evaporation and combustion is spherical evaporation in case of methanol and light oil. And fish oil blended with light oil was finished after spherical evaporation happen when high temperature. 2. Ignition of Pure fish oil was shorter than that of fish oil blended with light oil. 3. Heat transferred to droplet could make qualitative comparison by contact diameter of droplet with hot surface as time changes. Life time of droplet according to the change of heated surface temperature was greatly influenced by droplet contact condition on the heated surface. 4. As far as combustion phenomena was concerned, apparent diameter of the fish oil droplet increased after ignition and decreased suddenly by internal boiling of droplet. 5. Three fish oils had similar phenomena on the evaporation, ignition and combustion. 6. Evaporation and combustion feature of fish oil could not be shown by coefficient of evaporation velocity of droplet and coefficient of combustion velocity of droplet.

• Journal of Korea Water Resources Association
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• v.45 no.6
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• pp.557-568
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• 2012

In order to understand the hydrological processes on the mountainous forest, the configuration of soil evaporation (E) out of evapotranspiration (ET) is a challenging and important topic. In this study, we attempted to understand the soil evaporation process for a humid forest hillslope via measuring and analyzing soil moistures with a sampling interval in 2 hours at three locations for 10 days between May 22th and 31th 2009. Two methods were used to estimate soil evaporation in every 2hr; one is a method using soil moisture measurement ($E_{SM}$), the others methods are based on Penman equation (Penman (1948), Staple (1974), Konukcu (2007), Equilibrium Penman ($E_{equili}$)). As a critical parameter in determining $E_{SM}$, the dry surface layer (DSL), was estimated using energy balance equation. The accumulated soil evaporation ($E_{SM}$) of A, B, C points were estimated as 2.09, 1.08 and 2.88 mm, respectively. The estimated evaporation of Penman (1948), Staple (1974), Konukcu (2007), $E_{equili}$ were 4.91, 8.80, 8.63 and 3.28 mm. The proposed method with soil moisture measurement showed lower soil evaporations than the other conventional methods. The increasing soil temperature and interaction between soil and atmosphere due to existence of litter and DSL are considered as dominant factors for soil evaporation. The $E_{SM}$ has the apparent lag time between 2 and 4 hr compared with $E_{equili}$ and net radiation. The DSL and surface resistance ($r_s$) were increased as soil moisture was decreased for in this study. The estimated DSL through the temporal distribution analysis of soil moisture and tension measurements was also similar to that of the energy balance relationship.

• Fire Science and Engineering
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• v.15 no.2
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• pp.6-12
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• 2001

The objective of the present work is to examine the cooling effect of a water fire extinguishing agent containing NaBr(30%, w/w). The carbon steel and teflon were used as a hot solid. The temperature on the hot solid surface ranged from $70^{\circ}c$ to $116^{\circ}c$ and water droplet size was 2.6 mm in the experiments. It is suggested that regardless of the hot solid material, the indepth temperature of the case of NaBr solution is lower than that of pure water and the variation of indepth temperature of teflon is higher than that of carbon steel. Regardless of the hot solid material, the time averaged heat flux of the case of pure water is higher than that of NaBr solution. the apparent evaporation time of the case of pure water is shorter than that of NaBr solution.

• Korean Journal of Materials Research
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• v.23 no.10
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• pp.592-598
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• 2013

Graphene oxide powders prepared by two different drying processes, freeze drying and spray drying, were studied to compare the effect of the drying method on the physical properties of graphene oxide powder. The graphene oxide dispersion was prepared from graphite by chemical delamination with the aid of sulfuric acid and permanganic acid, and the dispersion was further washed and re-dispersed in a mixed solvent of water and isopropyl alcohol. A freeze drying method can feasibly minimize damage to the sample, but it requires a long process time. In contrast, spray drying is able to remove a solvent in a relatively short time, though this process requires exposure to a high temperature for a rapid evaporation of the solvent. The powders prepared by freeze drying and spray drying were characterized and compared by Raman spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and by an elemental analysis. The graphene oxide powders showed similar chemical compositions; however, the morphologies of the powders differed in that the graphene oxide prepared by spray drying had a winkled morphology and a higher apparent density compared to the powder prepared by freeze drying. The graphene oxide powders were reduced at $900^{\circ}C$ in an atmosphere of $N_2$. The effect of the drying process on the properties of the reduced graphene oxide was examined by SEM, TEM and Raman spectroscopy.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.2
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• pp.74-85
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• 1997

Accurate analysis of water budget and seawater exchange characteristics is essential for the improvement and management of the degraded water quality in Masan Bay. In this study, water budget is simulated for the four divided coastal zones on the monthly base, and watershed runoff discharges which are important as input parameters are estimated using the runoff coefficient(=0.7). The main results are as follows : The runoff-contribution rate due to water supply discharge is increased from 10% in 1978 to the equivalent amount at present. The reduction quantity due to the wastewater interception is about 25% of total inflow discharges, and the net effects of both precipitation and evaporation is about 10%. As the hydraulic detention time in Masan Bay is estimated about 3 months, water exchange rate is to be very low. From the analysis of the salinity variation on account of water mixing, it appears no temporal correlation between monthly average precipitation and salinity, whereas only regional correlation is apparent.

• Journal of Pharmaceutical Investigation
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• v.24 no.2
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• pp.95-104
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• 1994

Inclusion complexes of ketoconazole(KT) with ${\alpha}^_$, ${\beta}^_$cyclodextrin(CD) and $dimethy1-{\beta}-cyclodextrin$ (CD) and $dimethy1-{\beta}-cyclodextrin(DM{\beta}CD)$ as nasal absorption enhancer were prepared in 1: 2 molar ratios by freeze-drying and solvent evaporation methods. In order to compare with the intrinsic absorptivity of KT in the jejunum(J) and the nasal cavity(N), the in situ simultaneous perfusion method was employed. The in situ recirculation study revealed that KT-CD inclusion complexes with the greater stability constant and the faster dissolution rate proportionally increased the absorption of KT in the J and N of rats. The rank order of apparent KT permeability$(P_{app}\;:\;cm/sec\;{\time}\;1O^{-5}{\pm}S.E.)$, corrected by surface area of absorption, was $5.10{\pm}0.3(N,\; KT-DM{\beta}CD)$ )> $4.13{\pm}0.4(N,\;KT-{\beta}-CD)$ )> $3.52{\pm}0.2(N,\;KT-{\alpha}-CD)$ )> $2.76{\pm}0.3(J,\; KT-DM{\beta}CD)$ )> $2.61{\pm}0.5(J,\;KT-{\beta}-CD)$ )> $2.42{\pm}0.4(J,\;KT-{\alpha}-CD)$ at pH 4.0. The in crease in permeability of $KT-DM{\beta}CD$ inclusion complex was 2.6 folds in the J and 4.5 folds in the N when the perfusing solution was changed from the buffer(pH 4.0) to saline. The absorption rate of $KT-DM{\beta}CD$ inclusion complex after nasal administration was more rapid than those of ketoconazole alone and $KT-DM{\beta}CD$ inclusion complex after oral administration to rats. In comparision with an oral administration of ketoconazole suspension in corn oil, the relative bioavailability was calculated 137.3% for the oral and 195.0% for nasal $KT-DM{\beta}CD$ inclusion complex in rats. The present results suggest that $KT-DM{\beta}CD$ inclusion complex may serve as a potential nasal absorption enhancer for the nasal delivery of ketoconazole.