• Journal of ILASS-Korea
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• v.5 no.1
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• pp.5-12
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• 2000

The beneficial aspects of applying emulsion fuels to combustion systems may be due to the changes of fuel properties which lead to the enhanced atomization characteristics. The spray characteristics of water/oil emulsified fuel injected from the pressure-swirl(simplex) atomizer using for oil burner were investigated. Four different water contents from 10 to 40 % by volume at 10% increment were prepared by mixing with the different contents of surfactants. Total amount of surfactant used was varied from 1 to 3 % by volume. This study demonstrates the influence of water and surfactant contents of emulsified fuel, injection pressure on the spray characteristics, i.e. Sauter mean diameter(SMD) and spray angle. The drop size distribution of the emulsified fuel spray was measured with a Malvem particle sizer. In order to measure the spray angle, the digital image processing was employed by capturing multiple images of the spray with 3-CCD digital video camera. It was evident that the addition of water and surfactant changes fuel properties which are the key parameters influencing the atomization of the spray. The increase in surfactant content results in the decrease of SMD and the increase in spray angle. The droplets decease with increase in injection pressure, but the influence of injection pressure in this experimental condition was less important than expected. The more viscous fuel with the increase of water content exhibits the larger droplets in the centerline of the spray, and the less viscous fuel in the outer edges of the spray. The increase in axial position from the nozzle causes the spray angle to decrease. The spray angle decreases with increase in water content. This is due to increase in viscosity with increase in water content.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2178-2182
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• 2011

Recently, the synthesis of ordered macroporous materials has received much attention due to its potential use as photonic band gap materials.$^1$ In this study, we have used the three-dimensional (3D) latex array template impregnated with benzenesulfonic acid (BSA), which is capable of catalyzing the reaction using tetraethyl orthosilicate (TEOS) as a precursor and distilled water. The polystyrene (PS) templates were reacted with TEOS in $scCO_2$ at 40 $^{\circ}C$ and at 80 bar. In the reactor, TEOS was filtrated into the PS particle lattice. After the reaction, porous silica materials were obtained by calcinations of the template. The stability test of the PS template in pure $CO_2$ was conducted before the main experiment. Scanning electron microscopy (SEM) images showed that the reaction in $scCO_2$ takes place only on the particle surface. This new method using $scCO_2$ has advantages over conventional sol-gel processes in its capability to control the fluid properties such as viscosity and interfacial tension. It has been found that the reaction in $scCO_2$ occurs only on the particle surface, making the proposed technique as more rapid and sustainable method of synthesizing inverse opal materials than conventional coating processes in the liquid phase and in the vapor phase.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.277-284
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• 2004

Low carbon steels containing Si of up to $1.2\;wt\%$ were oxidized in air at 1373 K and 1523 K, i.e. below and above the eutectic temperature of FeO and $Fe_2SiO_4$. The influence of a impurity element, S on behavior of scale formation during oxidation was investigated by using $M\"{o}chssbauer$ spectroscopy and EDS. This allowed establishment of an interface oxidation model of Si-added steel depending on temperature and an impurity element. A compound of FeO and FeS was formed in the scale/matrix interface of low carbon steels containing S of up to $0.03\;wt\%$ oxidized above 1213 K of the eutectic temperature. This was flat formed between $Fe_2SiO_4$ nodules along the scale/matrix interface without selective oxidation. It is due to low viscosity and high wettability of the compound of FeO and FeS in liquid. Conventional metallographic examinations revealed that roughness of the scale/matrix interface in Si-added steels became flat as the content of S increased. It was independent of oxidizing temperature and Si content. Effects of oxidizing temperature and an impurity element content on descaling characteristics in Si-added steels were evaluated by using a hydraulic descaling simulator. Good descaling characteristics was attributable to this flatness of the scale/matrix interface.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.2
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• pp.1-12
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• 2002

Starch dissolved in paper-mill wastes, either as a result of poor retention on the paper web or recycling of surface-treated broke, was a major pollutant Laboratory tests were performed by using different kinds of starch as a surface treatment. It was concluded that the use of cationic starch can positively affect the level of starch dissolved in liquid effluents. When cationically modified starches were used for surface sizing, the starch was tightly bound to the paper fibers, it was not removed during the repulping of broke. The result of mill trial in fine paper manufacture for the application of low-viscosity cationic starches used in size press reduced COD load in the effluents and increased One Pass Retention. It had been found that when cationic starch used as a surface sizing agent, more starch was retained on or near the surface of the sheet than with conventional oxidized starches. Thus surface strengths and quality were improved. In addition it is possible to maintain the desired level of starch penetration into the fiber net and improve porosity, opacity and brightness. In contrast, in most cases, dusting problems are notably eliminated. Cationic surface sized starch improved black and color ink-jet print quality in terms of feathering and optical density of the print image. These improved properties were believed to be due to a combination of fiber bonding and surface orientation more uniform starch concentration on the paper surface was resulted. Moreover cationic charges in the paper surface lend themselves excellently to fix ink jet ink anionic in nature.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.2
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• pp.139-145
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• 1998

Filament winding method is widely used for composite fabrications using low viscosity liquid for-mation and processing asymmetrical structures of pressure vessel pipe rocket motor case etc. The filament winding method is affected by several parameters such as pot life of process time viscosi-ty of resin filament winding temperature and schedules curing condition and post curing condi-tion of resin. To develope high functional composite materials the rotation(5, 15, 20, 30rpm) of the winding machine was controlled by D.C motor. And the wiper to give proper tension was equipped between strand and resin bath. The resin is hooked by the design wiper. The adequate cure schedule was found by DSC. NOL ring test is carried out to investigate the basic physical properties such as design technology. The void contents in filament winding is generally higher than that of the prepreg laminated plate. These high contents of void can make a crack in resin in spite of low deformation. These problem was solved by giving tension in processing. To improve the characteristics of fiber volume fraction void contents resin/fiber bonding the winding speedc is changed under constant tension. It was found that resin impregnation was not different from in fiber contents void contents at the range of 0.5~1kg tension but it was found that resin was not impregnated at the above of 1.5kg tension. In burst test a pure PE liner was failed at a nozzle part under the $14kg/\textrm{cm}^2$ pressure but a pressure vessel of CNG was failed at a cylinder part under the $200kg/\textrm{cm}^2$ pressure.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.438-443
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• 1993

Physico-chemical properties of glucitol fatty acid polyesters (GPE)-one of the potential fat substitutes-were analyzed and compared with conventional edible oil. The refractive Index, apparent viscosity and melting point of S-GPE (soybean oil GPE) were 1.472, 103 cps. at $37^{circ}C\;and\;-53^{\circ}C$, respectively. S-GPE were liquid at room teperature and the Yellowness of S-GPE was slightly stronger than that of soybean oil. The acid value and smoke point of S-GPE were 0.06 and $200^{\circ}C$. To supplement the weak thermal stability of S-PEG, SP-GPE (soybean-palm blended oil GPE) was prepared with soybeanpalm blended oil (70% of soybean oil and 30% of palm oil). The appearance and color of SP-GPE was not much different from S-GPE but the smoke point of that was increased to $210^{\circ}C$. It means that thermal stability of GPE can be enhanced by increasing saturation of the fatty acid composing GPE. Because most of physico-chemical properties of S-GPE or SP-GPE were similar to conventional edible oil, they are expected to be considered as a potential fat substitute with further study for confirming the safety.

• Korean Journal of Food Science and Technology
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• v.15 no.4
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• pp.348-352
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• 1983

The atomization of barley tea concentrate with paint spray gun of two fluid nozzle was investigated. The physical properties of barley tea concentrate were correlated to the operating parameters; soluble solid concentration, viscosity, specific gravity and surface tension. The air to liquid feed ratios at various barley tea concentration were correlated to the air pressures applied. The diameters of sprays at various air pressures (from 164 mmHg to 564 mmHg) and soluble solid concentrations (from 3.1% to 25.2%) were also investigated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4747-4752
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• 2013

Physical characteristics of a magneto-rheological(MR) fluid can be influenced by a magnetic field. MR fluid is a suspension of micrometer-sized magnetic particles in a base liquid such as oil. Therefore, the key issue is dispersion stability because density of micrometer-sized magnetic particles are different from that of oil. In the present study, dispersion stability and physical characteristics along chemical compositions of MR fluid are investigated. 216 kinds of MR fluids are made by using magnetic powder(#2), surfactant(#2), base oil(#2), functional additive(#3), density(#3) and viscosity(#3). From experimental results, SEM photograph, magnetic flux density, supernatant and sediment of 216 kinds of MR fluids are obtained.

• Food Quality and Culture
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• v.2 no.1
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• pp.37-42
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• 2008

This research examined the quality characteristics of orange sauce samples prepared with different sugar contents in order to create a standardized recipe.In the foodservice industry, attempts have been made to make superior sauces, often resulting in error. In this study, different sugar contents were examined for orange sauce to determine why varied results occur during its preparation as well as the best methodology for preparing orange sauce. Quality characteristics such as color differences, spreadability, and pH were analyzed, as well as sensory evaluations of taste, texture, color and overall acceptability. The pH values of the orange sauce samples ranged from 3.6 to 3.63 and after the initial simmering of ingredients, the weight reduction rates of the sauces were 88, 75, 64, 63, and 64% for sugar contents of 200, 300, 400, 500, and 600 g respectively. Hunter's color L, a, and b values of the samples changed according to the sugar contents after simmering (1st sauce). The L and b values showed similar patterns, where increasing sugar content resulted in higher values; however, in the 2nd sauce, the pattern was reversed. This indicates that the color of the sauce was affected by sugar caramelization during the reduction process; however, the final color was modified by the additions of mayonnaise and butter as well as by aeration. In the sensory evaluation the sample containing 30% sugar (500 g) had significantly higher acceptability scores (p<0.05) for color, mouth feel, appearance, taste, and overall acceptability. Finally, the optimal ingredient ratios of the standardized orange sauce recipe were determine as: 48% total liquid consisting of orange juice and mandarin and orange fruit; 30% sugar; 10% mayonnaise and 11% butter.

• Polymer(Korea)
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• v.24 no.5
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• pp.589-598
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• 2000

In this study, various unsaturated polyester (UPE) resins were prepared from the condensation polymerization of mixtures of saturated (isophthalic acid : IPA) and unsaturated (maleic anhydride : MA) dibasic acids with propylene glycol (PG), neopentyl glycol (NPG). The critical surface tension (Υ$_{c}$) for the surface characteristics of a solid were estimated by Zisman plot, and the structure-property relationship was investigated by measuring the rheology of resins. The values of Υ$_{c}$ for glass of solid were 30.5 mNㆍm$^{-1}$ for UPE resin liquids. As the content of NPG in a PG/NPG glycol mixture increased, both the contact angle and the surface tension of the UPE resin liquids were found to decrease. The dynamic viscoelasticities of UPE resins with different glycol molar ratios were also measured. Shear rate dependence of viscosity and angular frequency dependence of storage, and loss modulus tended to decrease with increasing NPG content.