• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.7
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• pp.1398-1407
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• 1992

The prediction of heat loss during laminar flame propagation was carried out by measurement of gas pressure and visualization of flame propagation in the constant volume combustion chamber. And to validate the prediction, the instantaneous temperature at wall of combustion chamber was also measured. Consequently, it was found that heat loss was increased according to increasing of maximum flame travel distance, but rate of heat loss for heat release during laminar flame propagation was nearly constant. And heat loss depends on heat transfer area which was contacted the wall by burned gas regardless to spark plug location.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.4
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• pp.504-511
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• 2000

PIV(Particle Image Velocimetry) is a recently developed technique for visualizing the fluid velocity fields. Because it has several advantages over the LDV(Laser Doppler Velocimetry), it became one of the most popular diagnostic tools in spite of its short history. However, its application to combustion is restricted by some problems such as flame illumination, scattered light refraction, particle density variation due to heat release, the combined effect of abrupt change in particle density and fluid velocity on flame contour, and thermophoresis which is particle lagging due to temperature gradient. These problems are expected to be originated from the non-continuous characteristics of flames and the limitations of particle dynamics. In the present study, these problems were considered for the visualization of the instantaneous coaxial hydrogen diffusion flame. And the instantaneous flame contour was detected using particle density difference. The visualized diffusion flame velocity field shows its turbulent and meandering nature. It was also observed that the flame is located inside the outer shear layer and flame geometry is largely influenced by the vorticity.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1155-1160
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• 1999

The screening methodology modeling, dispersion modeling procedures for continuous and instantaneous releases of the gas phase flow from the storage tank and pressure relief valve were considered. This study was performed to develop the screening methodology for prediction and control of hazardous/toxic gas releases by estimating the 1-hr average maximum ground-level concentration of $Cl_2$ gas vs. downwind distance by incorporating source term model including the general/physical properties of released material and release mode of the $Cl_2$ storage tank of the chemical plant facilities, dispersion model, and meteorological/topographical data into the TSCREEN model. As the results of the study, it was found that dispersion modes of the dense gas were affected by the state of the released material, the released conditions, physical-chemical properties of released material, and the released modes (continuous and instantaneous releases), and especially largely affected by initial (depressurized) density of the released material and release emission rate as well as the wind velocity. Especially, this study was considered to release hazardous material as meteorological data. It was thought that this screening methodology can be useful as a preliminary guideline for application of the refined analysis model by developing the generic sliding scale methodology for various senarios selected.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.287-291
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• 2011

We solve the simple physical model for liquid pool spreading with vaporization semi-analytically for the first time, using perturbation techniques. The results are compared with those obtained using numerical methods. We use the evaporation rate per unit area as a perturbation parameter, and first-order solutions are obtained for continuous and instantaneous release. The two solutions are nearly identical with respect to the pool radius. The pool volumes are nearly the same at the early stage of the spread and then start to diverge.

• Korean Journal of Pharmacognosy
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• v.9 no.1
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• pp.33-39
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• 1978

The present study is involved with the prolactin secretion from anterior pituitary gland by ginseng saponin since it was handled down by tradition that ginseng might influence the milk secretion when it was given to nursing mother. To investigate the effect of saponin on the prolactin production or release from the anterior pituitary gland, cell culture study and whole animal studies were carried out. For the cell culture study, enzymatically dispersed anterior pituitary cells of rat anterior pituitary gland in HEPES buffers containing trypsin were used. Ginseng saponin was added to the culture media and the amount of prolactin produced in the cell culture media was determined by radloimmunoassay(RIA) technique. Dose-dependent increases of prolactin with ginseng saponin were observed, whereas, no change was observed without ginseng treatment. For the whole animal study, normal and castrated rats which previously cannulated into the heart via the right juglar vein were used. The prolactin concentration in plasma were determined by using the technique of RIA. In normal rats, prolactin concentration in plasma were elevated dramatically after 1 hour of ginseng saponin administration, whereas, instantaneous increases were observed in castrated rats. For prolactin assay by RIA, NIAMDD Rat Prolactin Kit and NIAMDD Rat Prolactin RP-1 were used as standard. The results indicate that ginseng saponins increase the release of prolactin from the anterior pituitary gland and production of prolactin from the cell in rats.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5B
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• pp.475-483
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• 2008

2D finite element model for analysis of transport of accidentally released pollutants in the flow was developed by SUPG method, and the mass balance of this model was checked though two example problems: line source and point source problem in the straight channel and unidirectional 2D flow field, respectively. All the test cases were simulated with both SUPG and conventional Galerkin method to compare the accuraccy of the numerical mass balance. Test results show that the model with SUPG can adequately conserve the released mass though simulation than the model using Galerkin method, so the developed model verified to be appropriate to solve this accidental mass release problem.

• Journal of the Korean Professional Engineers Association
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• v.19 no.2
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• pp.10-20
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• 1986

This paper describes a countermeasure of electric utilities and customer equipment in order to minimize an effect of sensitive electrical and electronic equipment on the voltage disturbances. After being studied, some schemes to solve were discovered. Firstly, in the electric utilities, the reduction of frequency and influence of voltage drop's time are not easy to realize because of the standpoint of effect and economy. Secondly, in the customer equipment, there are some equipment to minimize the voltage disturbances, Such as an UPSs, a noise suppressors and a power conditioners. One of them should be established on the computer control and automated systems, the electromagnetic switch of delay-release type should be adopted on the electromagnetic switch, the controlling circuit should be adopted on the variable speed motors which is being considered a countermeasure for a momentary under-voltage drops, the luminaire adhering a instantaneous restrike device should be adopted on the HID lamp. And also, the scheme of extending a setting time of relay on the undervoltage relay and the forming method of sequence which is automatic reclosing at this time of instantaneous suspension of an electric supply have been studied.

• Solar Energy
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• v.18 no.3
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• pp.89-94
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• 1998

The heat transfer characteristics of a fluidized bed latent heat storage system using encapsulated PCM was investigated. The cylindrical test section has the dimension of 50 mm I.D. and 40 cm in height. The phase change material(PCM) was the sodium acetate and was encapsulated by the multiple layers of PMMA and paraffin wax. The size of encapsulated PCM was $2{\sim}3mm$ and melting point was $58^{\circ}C$. The instantaneous heat storage and heat release rates were determined and the instantaneous heat transfer coefficient based on the fluidized bed volume was also determined. The effect of inlet temperature and velocity of heat transfer fluid on the heat transfer coefficient was also investigated.

• Journal of the Korean Institute of Gas
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• v.22 no.1
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• pp.18-25
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• 2018

As the industries become more developed, the amounts of hazardous materials have been increased. Because of that, the possibility of accidents in plants is expected to increase. Especially, the dispersions of toxic materials cause serious effect to human life and environment, So it is very important to confirm safety distance of discharge accident. For this paper, we proposed new algorithms for toxic liquid, such as benzene and acrylonitrile. and using this argorithm, we are going to predict safety distance. The scenario of accidental release was assumed to be the release of entire quantity in 10 minutes is defined as worst-case scenario and Instantaneous release. Also the release from a partial rupture of line is used as an alternative case scenarios as NICS(National Institute of Chemical Safety) guidelines. Using ALOHA program and the algorithm for liquid toxic materials and suggested the graph, as well as correlated equations which can utilize emergency responders.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.3
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• pp.209-221
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• 2002

In the present paper, a method which enhances the circulation of harbor waters by using wave energy was investigated. The overflow levee was selected as a coastal structure helping the harbor circulation, and was applied to Jeju-outer-port site so as to estimate its effectiveness quantitatively in probabilistic point of view. It was assumed that sea water influx rate through the overflow levee into the harbor depended upon wave height and tidal level and a functional relationship among them was calculated using the results of hydraulic experiment. The probability distribution of water influx could be obtained from hindcasted wave data and measured tidal elevations at Jeju harbor. The Gamma distribution was appeared to best fit the estimated influx distribution, and the optimal location of the levee was discussed. Finally, water quality purification effect was investigated by computing the contaminant material dispersion according to whether the levee was or not.