• Journal of Biosystems Engineering
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• v.22 no.3
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• pp.279-288
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• 1997

This study was worked out to obtain fundamental data needed for developing a continuous type dryer. The drying process in a cross-flow type continuous dryer was expressed as partial differential equations, and a drying simulation model for predicting rice moisture content, rice temperature, drying air absolute humidity, drying air temperature was developed by using the finite difference method. To validate the performance of the drying simulation model, a prototype continuous dryer was constructed in this study. The size of the test dryer was one-tenth to that of a commercial continuous dryer. The difference in the outlet rice moisture content between the predicted values and the measured values was within 0.5%, that of outlet rice temperature was below $3^{\circ}C$, that of drying air temperature in drying bed was within $8^{\circ}C$ and that of relative humidity of outlet drying air was big because of the different measuring point. In addition, a drying simulation model for a actual size continuous dryer with double flow was developed in this study. This drying simulation model included the rice mixing effect in the middle of drying length. The difference of outlet moisture content between the predicted and the measured values showed below 0.5% in this study.

• Food Science and Preservation
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• v.20 no.3
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• pp.289-295
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• 2013

The capacity of a pressure fan can be designed based on the air flow resistance of containers packed with fruits and vegetables in a pressure cooling system. This study was conducted to develop an air flow resistance model that was dependent on changes in the air flow rate and the method of stacking containers. The air flow resistance of a container packed with uniformly shaped balls was 1.5 times greater than the sum of the air flow resistance of a vacant container and that of a wire net container packed with only balls. In addition, the air flow resistance increased exponentially as the width of the stacks increased; however, the air flow resistance did not increase greatly as the length and height of the stacks increased, which indicates that the air flow resistance is primarily influenced by the width of the stack in the air flow direction. The air flow resistance in two lines of stacking was up to 17% less than that of the width of the stack. It was also possible to determine the air flow resistance using a function of the air flow resistance through a single container and develop a prediction model. A prediction model of air flow resistance that is dependent on the stacking method and the air flow resistance of a single container was developed.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.57-68
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• 1993

Air Wiping technique is widely used because of easy and efficient coating control in present CGL. Coaring weight is decided by nozzle header pressure, strip line speed and distance between strip and nozzle. Coating defects are results from unbalance of these factors and coating equipment calibration inaccuracy. Therefore, this study is mainly dealing with the cause of coating defects such as edge overcoating and coating deviation. The coptimum working condition is suggested by formulated coating model using collected working data. We developed two demension analysis program for air flow in nozzle and calculated dynamic pressure and air velocity with this program. The productivity and coating guality are improved by applying the result of this reserach.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.137-138
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• 2012

The two-equation soot model based on the transient laminar flamelet model is implemented for soot formation of laminar non-premixed $CH_4/Air$ flame with detailed chemical reaction mechanism and complex thermodynamic properties. The soot model represents nucleation, growth and oxidation with gas-phase chemistry. This represented unsteady flamelet soot model has been tested and compared using well verified reference calculation result obtained solving the Full Transport Equations method.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.570-571
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• 2010

• Journal of environmental and Sanitary engineering
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• v.18 no.3 s.49
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• pp.1-10
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• 2003

This study was aimed to investigate the influence on the vicinity by air pollutant generated from facility of the district heating located in local small town. We selected the seven areas arround the surroundings of facility of the district heating, compared the air quality evaluated before and after operations of the facility, and estimated the diffusion of air pollutant exhausted from the facility using a ISC model. The result was that the concentration of TSP before and after operations of the facility was 89${\sim}$94${\mu}$g/m$^3$,and 72${\sim}$81${\mu}$g/m$^3$, respectively and the latter showed a decline in concentration. Also, there was no relationship between straight distance from the facility of the district heating and the concentration of TSP. This result was applicable to cases of PM-10 and SO$_2$. We also investigated the influence on the air around the neighbored area by air pollutant produced from facility of the district heating using ISCLT3 model. The adding-concentrations of TSP, SO$_2$,NO$_2$, and CO were 0.0019${\sim}$0.00183${\mu}$g/m$^3$, 0.0029${\sim}$0.5648ppb, 0.2924${\sim}$l.9837ppb,and 0.0087${\sim}$0.0590ppb, respectively. It is predicted that each concentration is added to pollutant exhausted from facility of the district heating and is about 1/100${\sim}$1/180,000 of present air quality. This has a tiny influence on general air quality. According to this analysis, the concentration of air pollutant is less effected to pollutants expected by the facility of the district heating than other pollutants emitted from mobil source or industrial complex, and etc.

• Journal of the Ergonomics Society of Korea
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• v.25 no.4
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• pp.103-113
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• 2006

The purpose of this study was to evaluate an effect of the new air traffic control display designed by Ecological Interface Design [EID]. The methodology of EID has not been applied to the development of the air traffic control display so far. To design a new air traffic control display by EID, We implemented Work Domain Analysis about the air traffic control domain and made the Work Domain Model that consisted of the five levels of the Abstraction Hierarchy. We extracted the Information Requirement from the completed Work Domain Model and the extracted information requirements from the model were used to design the new air traffic control display. We evaluated an effect of the new air traffic control display designed by EID. Participants for evaluating consisted of 14 active military air traffic controller of the Republic of Korea Air Force. Experiment was designed two factors within subject. Factors manipulated in the experiment included displays type to compare the existing type with the new ecological interface type and included complexity to compare the effect of the high complex situation with the effect of the low complex situation. Response time about questions with relation to air traffic collision situation, accuracy, and subjective work load were measured. The results reveled that EID type's display has a significant effect on response time, accuracy, and subjective work load and verified that EID could be applied to the air traffic control domain that is more complex and dynamic.

• The Journal of the Acoustical Society of Korea
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• v.39 no.4
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• pp.227-236
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• 2020

This paper derives the insertion loss for the bubble layer of an air bubble curtain and an air masker which are used to reduce ocean anthropogenic noise such as the piling noise and the ship noise. The air bubble curtain is considered as a 'fluid-air bubble layer-fluid' model and the environment for the air masker is simplified as an 'vacuum-thin plate-fluid-air bubble layer-fluid' model. The air bubble layer in each model is assumed as the effective medium which has the complex wavenumber and the complex impedance corresponding to the bubble population distribution. The numerical simulations are performed to examine the insertion loss depending on the bubble population, the void fraction, and the thickness of the layer.

• Journal of the military operations research society of Korea
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• v.35 no.3
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• pp.1-15
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• 2009

Central supply depot of Air Force has been receiving and storing the goods from the inside and outside of the country. And it also has been distributing the goods to the air base by air, rail, road, etc. These goods have been called central goods. Among these central goods, 10% of them are transported by air and the amount of freight is increasing day by day. So, air transportation in the Air Force has been more important than ever. But, studies of demand estimation for activating air transportation are very difficient. This study verified the main factors affecting to air transportation and the function of regression model will be useful data for estimating air freight demand.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.5
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• pp.687-696
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• 2018

In order to develop effective emission abatement strategies for coal-fired power plants, we analyzed the shutdown effects of coal-fired power plants on $PM_{2.5}$ concentration in June by employing air quality model for the period from 2013 to 2016. WRF (Weather Research and Forecast) and CMAQ(Community Multiscale Air Quality) models were used to quantify the impact of emission reductions on the averaged $PM_{2.5}$ concentrations in June over Chungcheongnam-do area in Korea. The resultant shutdown effects showed that the averaged $PM_{2.5}$ concentration in June decreased by 1.2% in Chungcheongnam-do area and decreased by 2.3% in the area where the surface air pollution measuring stations were located. As a result of this study, it was confirmed that it is possible to analyze policy effects considering the change of meteorology and emission and it is possible to quantitatively estimate the influence at the maximum impact region by utilizing the air quality model. The results of this study are expected to be useful as a basic data for analyzing the effect of $PM_{2.5}$ concentration change according to future emission changes.