• Journal of Biosystems Engineering
• /
• v.20 no.3
• /
• pp.236-244
• /
• 1995

Droplet size is one of the important factors in the deposition and drift of agrichemical application. In this study, droplet size and its distribution of the three different sizes of ceramic hollow cone nozzles being used in the air carrier sprayer for apple production were investigated at the various nozzle pressures and the three air velocities. The Malvern particle size analyzer were used for the measurement of droplet size and its distribution. The important results emerged from th is study can be summarized as follows. 1. Discharged rate was increase with the increase of the nozzle diameter and pressure, amount of the difference was remarkable between the nozzle diameter of 1.0, 1.2 and 1.5 mm, but no difference were found between the diameter of 1.0 and 1.2 mm in the same nozzle pressure. 2. Mass median diameter were varied as 40~160 ${mu}m$ at the air velocity of 0 m/s, 70~140 ${mu}m$ of 15 m/s and 100~160 ${mu}m$ of 20 m/s 3. It appeared that the air velocity range of 15~20 m/s was desirable for both drift and deposition control in the given experimental conditions.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.1
• /
• pp.132-139
• /
• 1997

Spray characteristics of external mixing sonic twin-fluid atomization nozzles are investigated experimentally. Particle sizes are measured by the Fraunhofer diffraction method using the Malvern particle analyzer, and their radial distributions are obtained using the tomographical transformation technique. The spatial distribution of SMD shows that the drop size increases in the radial direction at a fixed liquid flow rate, and the distribution is getting uniform rapidly as the atomizing gas pressure increases. The SMD decreases as the liquid flow rate increases at a fixed GLR. It is found that the atomization efficiency of the flush type sonic nozzle is superior to that of protrusion type. The effect of laser beam diameter of the particle analyzer on the spatial SMD distribution is minor at present experimental conditions.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.4 no.1
• /
• pp.177-186
• /
• 1996

A convolution alogorithm combined with Fourier transformation is applied to the tomographic reconstruction of the asymmetric spray structure to identify the local drop size and volume concentration. The line of sight intergrated data from Malvern particle analyzer with multiangular scanning form a basic information for the deconvolution. Linear interpolation is tested to obtain the effect of increasing number of scanning angles. This transformation method predicts well the structure of asymmetric spray. The tehnique can be extended to other line of sight combustion diagnostics.

• Journal of the Korean Society of Visualization
• /
• v.2 no.1
• /
• pp.25-31
• /
• 2004

Droplet size is one of the most important parameter which controls the performance of the combustion system using liquid fuel or oxidizer. Droplet formation and its size are mainly affected by the injection velocity and ambient gas density. Recently, droplet size measurement was conducted by PDPA or Malvern particle analyzer using laser light. But at this paper image processing method was developed to measure droplet size. And its validation was investigated with reticle.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.8
• /
• pp.1056-1067
• /
• 1997

Present study visualized flow pattern and investigated spray characteristics of twin-fluid atomization with converging-diverging nozzles. Particle sizes were measured by using the Malvern particle analyzer, and the radial size distributions were evaluated by using the tomographic transform technique. The results show that the SMD generally increases in the radial direction at a prescribed liquid flow rate and the increasing rate in the SMD becomes gradual as atomizing gas pressure increases. The SMD decreases as the liquid flow rate increases at a fixed GLR (gas/liquid mass ratio). The atomization performance of the protrusion-type nozzle turned out to be superior to that of the flush-type. However, in the case of the protrusion-type, flow separation occurs outside the liquid delivery tube when the pressure at the gas nozzle chamber is high enough, which may deteriorate the atomization performance.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.3
• /
• pp.1005-1014
• /
• 1996

An experimental investigation has been carried out to examine the influence of injector design variables and operating conditions on the resultant drop size for triplet impinging streams injectors. The variables studied in this investigation are pressure drop, impinging angle, orifice length to diameter ratio, and impinging point distance. Droplet-size data are obtained using water as the propellant simulant by Malvern Particle Analyzer System. Drop size decreases with increasing impinging angle and pressure drop while other injector parameters remain constant at the same point. But it is found that there is no noticeable droplet-size change which results from change in orifice length to diameter ratio or impinging point distance within the investigated range.

• Journal of Mechanical Science and Technology
• /
• v.18 no.6
• /
• pp.1002-1009
• /
• 2004

Direct contact air conditioning systems, in which heat and mass are transferred directly between air and water droplets, have many advantages over conventional indirect contact systems. The purpose of this research is to investigate the cooling and heating performances of direct contact air conditioning system for various inlet parameters such as air velocity, air temperature, water flow rate and water temperature. The experimental apparatus comprises a wind tunnel, water spray system, scrubber, demister, heater, refrigerator, flow and temperature controller, and data acquisition system. The inlet and outlet conditions of air and water are measured when the air contacts directly with water droplets as a counter flow in the spray section of the wind tunnel, and the heat and mass transfer rates between air and water are calculated. The droplet size of the water sprays is also measured using a Malvern Particle Analyzer. In the cooling conditions, the outlet air temperature and humidity ratio decrease as the water flow rate increases and as the water temperature, air velocity and temperature decrease. On the contrary, the outlet air temperature and humidity ratio increase in the heating conditions as the water flow rate and temperature increase and as the air velocity decreases.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.20 no.2
• /
• pp.36-41
• /
• 2016

Purpose Sentinel lymphoscintigraphy (SLS) was using only $^{99m}Tc-phytate$. If the supply is interrupted temporarily, there is no alternative radiopharmaceuticals. The aim of this study measure the particle size of radiopharmaceuticals and look for radiopharmaceuticals which can be substituted for $^{99m}Tc-phytate$. Materials and Methods The particle size of radiopharmaceuticals were analyzed by a nano-particle analyzer. This study were selected known radiopharmaceuticals to be useful particle size for SLS. We were divided into control and experimental groups using $^{99m}Tc-DPD$, $^{99m}Tc-MAG3$, $^{99m}Tc-DMSA$ with $^{99m}Tc-phytate$. For in-vivo experiment, radiopharmaceuticals were injected intradermally at both foot to perform lymphoscintigraphy. Imaging was acquired to dynamic and delayed static image and observe the inguinal lymph nodes with the naked eye. Results Particle size was measured respectively Phytate 105~255 nm (81.9%), MAG3 91~255 nm (98.7%), DPD 105~342 nm (77.3%), DMSA 164~ 342 nm (99.2%), MAA 1281~2305 nm (90.6%), DTPA 342~1106 nm (79.4%), and HDP 295~955 nm (94%). In-vivo delayed static image, inguinal lymph nodes of all experiment groups and two control groups are visible to naked eye. however, $^{99m}Tc-MAG3$ of control groups is not visible to naked eye. Conclusion We were analyzed to the particle size of the radiopharmaceuticals that are used in in-vivo. Consequently, $^{99m}Tc-DPD$, $^{99m}Tc-DMSA $are possible in an alternative radiopharmaceuticals of emergency.

• Applied Chemistry for Engineering
• /
• v.9 no.3
• /
• pp.457-461
• /
• 1998

The vesicle system of DPPC(dipalmitoylphosphaticylcholine)/Chol(Cholesterol) has been modified by incorporating various mole fractions of flourinated surfactant($C_8F_{17}(CH_2)_2OCO-CH_2CH(SO_3Na)COO(CH_2)_2C_8F_{17}$. Sodium bis(1H,1H,2H,2H-heptadecaflurododecyl)-2-sulfosuccinate, FS)/fluorinated fatty acid salt ($C_7F_{15}COONH_4$, ammoniumpentadecaflurooctyrate, FFS), and their physicochemical properties have been investigated in an attempt to enhance the stability of phospholipid vesicle system. The ${\zeta}$-potential measurement by use of Zetamaster sub-micron Particle Electrophoresis Analyzer (Malvern Co.) showed that a charged homogeneous DPPC/Chol/FS vesicle has been formed owing to the incorporated FFS effect on the membrane, playing a role as a cosurfactant in the bilayer between DPPC and FS components. With increase in the concentration of FFS, it was found that the particle size and also surface charge of the DPPC/Chol/FS vesicle decreased. The stability of DPPC/Chol/FS/FFS liposome was found to be enhanced significantly compared to that of DPPC/Chol/FS according to the dispersity change as a function of time. The release rate of dye molecule of Methylene Blue from the DPPC/Chol/FS/FFS vesicle was determined to be slower than that of DPPC/Chol/FS system, and it may be attributed to the increase in microviscosity of the hydrophobic region in the bilayer. The affinfinity of DPPC/Chol/FS/FFS vesicles to albumin was found to be slightly lowered compared to that of DPPC/Chol/FS. Based on these findings, it was confirmed that a more stable and homogeneous vesicle system of DPPC/Chol/FS could be prepared by addition of FFS, acting as a cosurfactant in the aggregate formation.