• Journal of ILASS-Korea
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• v.9 no.3
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• pp.15-21
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• 2004

The removal of the dusts in the subway stations, tunnels, factories and buildings becomes issue for comfortable indoor and outdoor conditions. There has been used an automatic self-cleaning filter system to collect the dusts. In general, the collected particles are removed by water spray nozzles. The new design for improving the cleaning efficiency of collected dusts and reducing the supplied water is the concept of the plane array of demister filters and the twin-fluid nozzle for mixing compressed air and water in the automatic self-cleaning filter system. Results show that the cleaning efficiency of twin-nozzle filter systems is 99.1%, compared to 47% in the conventional filter system. Therefore the automatic self-cleaning filter system using twin-fluid nozzle filter systems reduces water supplied in the filter system, and increases cleaning efficiency and drying efficiency.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.1
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• pp.57-63
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• 2007

The oxidizer-rich preburner is applied to the high efficiency closed cycle rocket propulsion system. This system is generally operated on oxidizer-fuel mixture ratio over than 50. The spray quality and mixing performance are very important for stable combustion of this preburner. This paper presents basic design concept and spray characteristic of the oxidizer-rich preburner injector and this result could be applied to the development of the oxidizer rich preburner system.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.4
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• pp.478-486
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• 2007

Numerical analysis had been performed to understand flow characteristics of the flue gas and slurry in the absorber of a flue gas desulphurization (FGD) system using computational fluid dynamics (CFD) technique. Two-fluid(Euler-Lagrangian) model had been employed to simulate physical phenomenon, which slurry particles injected through slurry spray nozzles fall down and bump into the flue gas inflowing through inlet duct. It was not necessary to adopt pre-defined pressure drop inside the absorber because interaction between flue gas and slurry particles was considered. Hundreds of slurry spray nozzles were considered with the spray velocity at the nozzles, swirl velocity and spreading angle. The results note that the flow disturbance of flue gas is found at the bottom of the absorber, and the current rising with high speed stream is observed in the opposite region of the inflow duct. The high speed stream is reduced as the flue gas goes up, because the high speed stream of flue gas dumps falling slurry particles due to momentum exchange between flue gas and slurry particles. In spite of some disproportion in slurry distribution inside the absorber, escape of slurry particles from the absorber facility is not observed. The pressure drop inside the absorber is mainly occurred at the bottom section.

• Journal of Pharmaceutical Investigation
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• v.31 no.4
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• pp.257-263
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• 2001

The microspheres have been developed as a new drug delivery system. Although many particulate drug carriers, such as liposome, niosome and emulsion, have been introduced, injectable and biodegradable microspheres appears to be a particularly ideal delivery system because the local anesthesia is not necessary for the insertion of large implants and for the removal of the device after the drug release is finished. Biodegradable microspheres with nicotine and triamcinolone acetonide are prepared and evaluated. As biodegradible polymers, PLA (M.W. 15,000, PLA-0015), PLGA (M.W. 17,000, RG 502) and PLGA (M.W. 8,600, RG 502H) are used. This study attempted to prepare and evaluate the nicotine and triamcinolone acetonide-incorporated microspheres, which were prepared by two methods, solvent-evaporation and spray-drying methods. The microspheres, as a disperse system for injections, were evaluated by particle size, size distribution, entrapment efficiency, and in vitro drug release patterns. The differences of preparation method, partition coefficient, types of polymer, and preparation conditions of microspheres influence the particle size, entrapment efficiency, and in vitro drug release patterns.

• Journal of Pharmaceutical Investigation
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• v.30 no.4
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• pp.253-258
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• 2000

In order to design the oral vaccine delivery system, we prepared the alginate micro spheres containing GFP (green fluorescent protein) as a model drug by spray method. To optimize the preparation conditions of microspheres, we investigated the effects of various parameters including nozzle pressure, nozzle opening angle, and concentrations of sodium alginate and calcium chloride. The prepared microspheres were evaluated by measuring their sizes, loading efficiency, and morphology. The particle size of microspheres was affected by the concentration of sodium alginate and calcium chloride, nozzle pressure, and nozzle opening angle. As the concentration of sodium alginate increased, GFP loading efficiency and particles size of microsphere also increased. However, it was observed to be difficult to spray the sodium alginate solution with concentration greater than 1.5% (w/v), due to high viscosity. The pressure over $3\;kgf/cm^2$ didn't affect the size of particles. As a result, the spraying method enabled us to prepare microspheres for oral vaccine delivery system. In this study, microspheres prepared with 1% (w/v) sodium alginate had greater loading efficiency and better spherical shape.

• Journal of the Society of Disaster Information
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• v.17 no.1
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• pp.120-127
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• 2021

Purpose: In this study, the effect of changes in the variables related to water droplets on the spray density on the floor in the analysis of the water mist fire protection system using FDS was analyzed. Method: When the spray of the water mist nozzle was analyzed in FDS, Particles Per Seconds, Particle Velocity, Size Distribution, and Spray Pattern Shape that can be set in relation to droplets were input to review the analyzed results. Result: In the analysis results, when the number of particles per second was set above a certain value, the spray density of the floor was similar. In the case of Particle Velocity, as the velocity decreases, the spray density of the central portion increases but decreases at a distance of 0.15m or more. From the analysis of the change in the size distribution function, it was found that an increase in the 𝛾 value increases the spray density of the central part, but the value at a remote location decreases. Compared to the result of applying the Gaussian distribution, the median value decreases dramatically when the uniform distribution is applied, but the value at the adjacent position increases. Conclusion: Variables related to the droplet properties of the FDS affect the spray density of the floor. Therefore, in order to increase the reliability of results before performing analyses such as fire suppression or cooling, a sufficient review of input variables is required.

• Journal of ILASS-Korea
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• v.18 no.3
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• pp.119-125
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• 2013

Digital holographic particle velocity measurement system can be a promising optical tool for the measurements of three dimensional particle velocities. In this research, validation experiments for the digital holographic particle velocity measurement system were conducted with measuring the velocities of glass beads on a rotating disk. Uncertainty analysis was performed to identify the sources of all relevant errors and to evaluate their magnitudes. The measurement results of particle velocities obtained with digital holographic method are compared reasonably well with the known values within acceptable range of errors. Moreover, digital holographic method showed better performance compared with that of optical holographic system.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1755-1760
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• 2004

The holographic velocimetry system has a significant potential for the measurements of three dimensional velocities of particles. In this study, orthogonal two-side holography system was developed to obtain three dimensional velocities and sizes of spray droplets. To get high quality of reconstructed images, singe-exposure holography at two time moments and two orthogonal sides was adopted instead of multi-exposure, single-side holography. From three dimensional positions of droplets determined by reconstruction and image processing system, the three dimensional velocities and sizes of each droplet was extracted using the PTV algorithm. To determine the position of particles in the optical axis, a new focusing parameter was introduced based on the correlation between two droplet images at the same distance. The measured results by holography system were compared with those by the PDPA.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.6
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• pp.50-56
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• 1994

This is an experimental study on the performance characteristics of Diesel Automobile with ultrasonic fuel feeding system. For this purpose, ultrasonic fuel feeding system was made and atomization characteristics was measured. Base on this result, carried out engine dynamometer test to investigate the performance characteristics of diesel automobile with ultrasonic fuel feeding system in comparison with conventional diesel fuel injector. The results are as follows. 1) In the spray characteristics test, fuel particle sizes were decreased about 11%~21%. 2) In engine dynamometer test, -The power was increased about 5%~11%. -The thermal efficiency was improved about 6%~11%. -The specific fuel consumption was improved about 6%~19%. -The smoke concentration was decreased about 11%~50%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.611-614
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• 2008

Urea-SCR system has been known so far as one of effective after treatments for the reduction of NOx. In order to achieve better performance in SCR system, optimal geometric conditions for a urea injection system should be achieved. This research focused to visualize spray characteristics of urea injected SCR system in a heavy duty diesel engine. The experiment was conducted by varying injection pressures and flow rates of urea. The flow visualization was made by photographing techniques of CCD camera.