• 대한기계학회논문집B
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• 제20권6호
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• pp.1941-1947
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• 1996

Droplet size measurement technique was established for the sprayed viscous fluid by virtue of the installation of the sprayed-droplet size measurement system employing light scattering method. Atomization test results showed that the mean droplet size of the sprayed viscous fluid is decreased with the increase of the mass ratio of air to fuel and in case of the same air/fuel ratio, also with the increase of viscous fluid flow rate, and is increased with the distance from atomizer tip. Basic design data for the manufacture of external-mixing type, Y-Jet type, and internal-mixing type atomizers was acquired from the atomization tests.

• Journal of Biosystems Engineering
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• 제24권2호
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• pp.107-114
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• 1999

To find the best combustion conditions in the heavy oil burner kinetic viscosity of heavy oil A, B and C at different temperature range, from 40 to 140$^{\circ}C$, and the droplet sizes of the heavy oils at different temperature and pump pressure were measured. And, combustion characteristics were investigated under the different conditions : two different heavy oil and three different oil temperature. At temperature of 70, 100, 130$^{\circ}C$ the kinetic viscosity of heavy oil A and B are 7.9, 5.7, 4.3 and 30.4, 13.7, 7.9cSt, respectively. The greatest and smallest viscosity were 7,455 cSt at C oil on 27$^{\circ}C$ and 4.26cSt at A oil on 140$^{\circ}C$. The magnitude of viscosity difference between at 100$^{\circ}C$ and 140$^{\circ}C$ under 6 cSt in cases of A and B oil, but more than 30cST on C oil. Of the droplet sizes, the biggest and smallest droplet size in A oil were 98$\mu\textrm{m}$ at oil temperature of 130$^{\circ}C$(4.3cSt), pump pressure of 1.57MPa and 72$\mu\textrm{m}$ at 70$^{\circ}C$(7.9cSt), 2.35MPa, respectively. It appeared that as spraying pressure increased the droplet size decreased, however, no distinct differences were found in the effects of kinetic viscosity on the droplet sizes of the test range. The best combustion performance was observed when droplet size, spraying pressure and oil temperature were 73$\mu\textrm{m}$, 2.35MPa and 70$^{\circ}C$ producing CO2 of 13.1%, CO of 13ppm and flue gas temperature of 250$^{\circ}C$ in A oil combustion For B oil, it was100$^{\circ}C$, 2.35MPa, 52$\mu\textrm{m}$, producing CO2 of 10ppm and flue gas temperature of 260$^{\circ}C$. In general, it appeared that better combustion results were observed in the smaller droplets produced burner condition.

• Korean Chemical Engineering Research
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• 제51권6호
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• pp.760-765
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• 2013

액적기반 미세유체 시스템을 이용해 난백단백질인 라이소자임의 결정화실험을 하였다. Flow-focusing 칩을 이용해 water-in-oil 형태의 액적을 만들고 페트리 디쉬와 십자몰드에 넣은 후, 액적 내부에서 라이소자임 수용액과 침전제 (NaCl) 사이의 액-액 반응을 관찰하였다. 그리고 수용액의 pH가 4.8일 때와 7.2일 때의 결정형태를 비교하였다. 그 결과, pH 4.8에서는 다면체 또는 판상형의 결정이 형성되었고, pH 7.2에서는 침상형 결정이 생성되었다. pH 4.8, 7.2 두 경우 액적이 홀로 있을 때에는 액적부피가 유지되거나 감소하면서 결정이 형성되었다. 하지만 액적이 서로 인접해 있을 때는 액적사이의 상호작용이 관찰되었고, 두 pH에서 다른 경향성을 보였다. pH 4.8에서는 인접한 액적의 부피에 영향을 주어 한 액적의 부피가 커졌고, 부피가 커진 액적에서 결정이 형성되었다. pH 7.2에서는 부피에 영향을 서로 주지 않고 각각의 액적에서 결정이 형성되었다.

• Food Science and Biotechnology
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• 제17권3호
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• pp.664-668
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• 2008

The diffusivity of aerosol sanitizers may be determined by the weight and droplet size of the aerosol. To test the effects of droplet size, 2 types of aerosol sanitizers were prepared using different ultrasonic nebulizer frequencies (1.6 and 2.4 MHz) and their reduction activities were determined against Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella typhimurium. A sodium hypochlorite aerosol was treated for 10, 30, or 60 min in a model aerosol cabinet. When the aerosol prepared by nebulizing at 1.6 MHz was treated for 30 min, a 0.2 log reduction was observed in E. coli O157:H7 and 0.3 log reductions were exhibited in L. monocytogenes and S. typhimurium, respectively. After 60 min, the 3 pathogens were reduced by 1.7, 0.6, and 0.8 log units, respectively. However, when the aerosol prepared by nubulizing at 2.4 MHz was treated, the microbes presented 1.6, 0.5, and 0.6 log reductions at 30 min, and 1.8, 0.9, and 1.1 log reductions at 60 min of treatment, respectively.

• Corrosion Science and Technology
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• 제3권2호
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• pp.47-53
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• 2004

The conditions to simulate the atmospheric corrosion behavior in the laboratory were investigated to clarify atmospheric corrosion mechanism of steel material in coastal area, For airborne sea salt and artificial seawater droplet, the various behaviors were observed by optical microscope, The particle size of the dried airborne sea salt was about $20{\mu}m$, and was about 1/10 compared with the artificial seawater droplet. Though the airborne sea salt represented the same behavior as the thermodynamic water absorption, the behavior of the artificial seawater droplet deviated from the results of the thermodynamic calculation, It is concluded that the water absorption behavior is influenced by the particle size of the dried sea salt. The corrosion behaviors of carbon steels were observed under the deposited condition of airborne sea salt and artificial seawater droplet. The corrosion behaviors showed a different trend, indicating that the corrosion behavior depended on the particle size of the dried sea salt. The corrosion in the actual environrnent progressed greater than that in the chamber. Furthermore, the summer showed the greater corrosion than the spring. It is found that the corrosion behaviors are attributed to the influence of the environmental factors.

• International Journal of Automotive Technology
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• 제2권4호
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• pp.165-170
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• 2001

This study is focussed on the investigation of spray characteristics from the high pressure gasoline injector for the application of gasoline direct injection engine. For the analysis of spray structure of high pressure gasoline injector; the laser scattering method with a Nd-Yag laser and the Phase Doppler particle analyzer system were applied to observe the spray development and the measurement of the droplet size and velocity of the spray, respectively. Also spatial velocity distribution of the spray droplet was measured by use of the particle image velocity system. Experimental results show that high pressure gasoline injector shapes the hollow-cone spray, and produce the upward ring shaped vortex on the spray surface region. This upward ring shaped vortex promotes the secondary atomization of fuel droplets and contributes to a uniform distribution of fuel droplets. Most of fuel droplets are distributed under 31$\mu m$ of the mean droplet size (SMD) and the frequency distribution of the droplet size under 25$\mu m$ is over 95% at 7 MPa of injection pressure. According to the experimental results of PIV system, the flow patterns of the droplets velocity distribution in spray region are in good agreement with the spray macroscopic behaviors obtained from the visualization investigation.

• 한국분무공학회지
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• 제16권1호
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• pp.27-36
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• 2011

The impact force on the single and overlap region of twin spray was experimentally evaluated using visualization method in full cone type swirl nozzle spray. Visualization of spray was conducted to obtain the spray angle and breakup process. The photography/imaging technique, based on Particle Image Velocimetry (PIV) using high-speed camera, was adopted for the direct observation of droplet motion and axial velocity measurement, respectively. Droplet size was measured by Particle Motion Analyze System (PMAS). The purpose of this study is to provide fundamental information of spray characteristics, such as impact force, for higher etching factor in the practical wet etching system. It was found that the spray angle, axial velocity and impact force were increased with increasing the nozzle pressure while droplet size decreased with increasing the nozzle pressure. Droplet size increased as the distance from nozzle tip was decreased. The impact force of twin spray in the overlap region was about 63.29, 67.02, 52.41% higher than that of single spray at 40, 50 and 60 mm of nozzle pitch, respectively. Also, the nozzle pitch was one of the important factors in the twin spray characteristics.

• 대한기계학회논문집B
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• 제23권10호
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• pp.1310-1319
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• 1999

High-pressure swirl injectors have usually been employed in Gasoline direct injection engines due to their spray characteristics and the feasibility of their control. Thus the microscopic characteristics of high-pressure swirl spray were investigated by PDA. The correlation between axial and radial velocities and the correlation between droplet size and axial velocity were examined with different axial and radial positions. Two dimensional droplet velocity and its number distribution with size-classified droplets were illustrated. The mean droplet velocity and its SMD were also analyzed at the center of spray, the position having maximum mean axial velocity, and the spray periphery using time dividing method. Finally, the structure of high-pressure swirl spray was presented with the size distribution and velocity profile of droplets.

• 동력기계공학회지
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• 제10권4호
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• pp.5-10
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• 2006

The purpose of this study is to measure the droplet distribution and Sauter mean diameter(SMD) of biodiesel fuel, using the immersion sampling method. This method involves using an optical microscope and a CCD camera, to take an image of the droplets. These images are then measured by using a 'Sigma Scan' processing program. The results of the above experiment are summarized as followed ; (1) There can be as much as a 10% error rate when measuring the diameter of these droplets, using the image processing method and the naked eye. (2) The result of droplet size distribution test, TVO(transesterified vegetable oil) big size droplet distribution were increased at ambient pressure $6kg/cm^2$. (3) When ambient pressure increased $6kg/cm^2$ above, SMD variation of TVO and UVO(used vegetable oil) 30 are small. (4) On Rosin-Rammler analysis, droplets size distribution of UVO(used vegetable oil) 30 uniform more than TVO 20 on ambient pressure $1kg/cm^2$.

• 한국분말재료학회지
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• 제30권6호
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• pp.493-501
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• 2023

This study aimed to develop a solid self-nanoemulsifying drug delivery system (solid-SNEDDS) to enhance the formulation of ketoconazole (KTZ), a BCS Class II drug with poor solubility. Ketoconazole, which is insoluble above pH 3, requires solubilization for effective delivery. This SNEDDS comprises oil, surfactant, and co-surfactant, which spontaneously emulsify in the gastrointestinal tract environment to form nanoemulsions with droplet sizes less than 100 nm. The optimal SNE-vehicle composition of oleic acid, TPGS, and PEG 400 at a 10:80:10 weight ratio was determined based on the smallest droplet size achieved. This composition was used to prepare liquid SNEDDS containing ketoconazole. The droplet size and polydispersity index (PDI) of the resulting liquid SNEDDS were analyzed. Subsequently, solid-SNEDDS was fabricated using a spray-drying method with solidifying carriers such as silicon dioxide, crospovidone, and magnesium alumetasilicate. The physicochemical properties of the solid-SNEDDS were characterized by scanning electron microscopy and powder X-ray diffraction, and its solubility, droplet size, and PDI were evaluated. In particular, the solid-SNEDDS containing ketoconazole and crospovidone in a 2:1 weight ratio exhibited significantly enhanced solubility, highlighting its potential for improved medication adherence and dissolution rates.