• Journal of Soil and Groundwater Environment
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• v.19 no.6
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• pp.1-5
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• 2014

The following research was initiated in order to compare the relationship between the amount of gunfire shot and its resulting heavy metal pollution rate. The research was conducted at two firing ranges located inside a military unit stationed in the rear strategical area, where one full distance firing range is used by soldiers in active service, and the other is used by recruits and reserves. The heavy metal pollution rate was measured also on water sample collected from the target zone while raining. Based on values such as the real amount of gunshot fired, amount of heavy metal in the soil of the target zone, and the degree of heavy metal pollution for each firing range, the research showed that although pollution rate was higher when more gunshots were fired, there was no close correlation between the two. The water samples showed that this might result from the soils containing heavy metals eroded and transported by rain due to the target zone having no vegetation.

• Korean Chemical Engineering Research
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• v.55 no.4
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• pp.548-555
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• 2017

This study investigated the influence of air staging on combustion and NOx emission in a tangential-firing boiler at a 560 MWe capacity. For air staging, the stoichiometric ratio (SR) for the burner zone was varied from 0.995 to 0.94 while the overall value was fixed at 1.2. The temperature and heat flux in the burner zone and upper furnace corresponded to the distribution of SR, while the total boiler efficiency remained similar. The NOx emission at the furnace exit was reduced by up to 20% when the SR in the burner zone decreased to 0.94. However, the amount of unburned carbon and slagging propensity was not noticeably influenced by the changes in the SR of the burner zone. Therefore, it was favorable to lower the SR of the burner zone for reduction of NOx emission.

• Journal of the Korean Society of Combustion
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• v.21 no.4
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• pp.30-38
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• 2016

Flame structure of co-firing coal and palm kernel shell (PKS) was investigated in a pulverized coal swirl burner by particle image velocimetry (PIV). The pulverized coal swirl flame is operated with a PKS blending ratio of 10%, 20%, and 30%. For all operating conditions, flame structures such as internal recirculation zone (IRZ), outer recirculation zone (ORZ), and exhaust tube vortex (ETV) were observed. In the center of flame, the strong velocity gradient is occurred at the stagnation point where the volatile gas combustion actively takes place and the acceleration is increased with higher PKS blending ratio. OH radical shows the burned gas region at the stagnation point and shear layer between IRZ and ORZ. In addition, OH radical intensity increases for a co-firing condition because of high volatile matter from PKS. Because the volatile gas combustion takes place at lower temperature, co-firing condition (more than 20%) leads to oxygen deficiency and reduces the combustibility of coal particle near the burner. Therefore, increasing PKS blending ratio leads to higher OH radical intensity and lower temperature.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.3
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• pp.163-170
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• 2000

Accident statistics shows that the portion of fatal occupant injuries due to side impacts is considerably high. The side impact usually leads to a severe intrusion of side structure into the passenger compartment. Furthermore, the safety zone for the side impact is relatively small compared to the front impact. Those kinds of physics for side impact frequently result in a fatal injury for the occupant. Therefore, NHTSA and EEVC are trying to intensify the regulation for the occupant protection against side impact. Both the regulation and recent market trends are asking for an installation of side airbag. There are several types of system configuration for side impact sensing. In this paper, we adopt the acceleration-based remote sensing method for the side airbag control system. We mainly focus on the development of hardware and crash discrimination algorithm of remote sensing unit. The crash discrimination algorithm needs fast decision of airbag firing especially for high-speed side impact such as FMVSS 214 and EEVC tests. It is also required to distinguish between low-speed fire and no-fire events. The algorithm should have a sufficient safety margin against any misuse situation such as hammer blow, door slam, etc. This paper introduces several firing criteria such as acceleration. velocity and energy criteria that use physical value proportional to crash severity. We have made a simulation program by using Matlab/Simulink to implement the proposed algorithm. We have conducted an algorithm calibration by using real crash data for 2,500cc vehicle. The crash performance obtained by the simulation was verified through a pulse injection method. It turned out that the results satisfied the system requirements well.

• Journal of the Korean Society of Safety
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• v.35 no.3
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• pp.79-85
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• 2020

Ahn-heung Proving Ground(APG) of Agency for Defense Development(ADD) is the only weapon test site which has been performing firing tests for many kinds of missile, artillery and ammunition. APG has been performing the firing tests of so many times every year. The tests related to missiles, artillery and ammunitions cover 80% among the quantity of annual test events. The target area of many kinds of missile, artillery and ammunition is on the sea. Therefore, APG has its marine firing ranges which were approved by the ministry of Defense. Both weapons and ships can run into each other on the sea. APG has to monitor and detect the positions of the ships in the specific dangerous zone on the sea. The positions of the ships are detected by Scanter 2001 radar and GPS100 detection radar. Evading the time period when the ships appear very often on the sea may be a good solution to keep the maritime safety. And evading the place where the ships appear very often on the sea may be a good solution as well. This paper is to analyze the ships' distribution characteristics of marine firing range, which are to raise the efficiency of many kinds firing tests which have been performed in APG of ADD. Ship distribution data from February 2014 to December 2016 were used in this paper. Ship distribution was analyzed with monthly data, seasonal data and etc. The number of the ships in approved sea area is higher in the morning than in the afternoon, and in fall than other seasons, and from August to November, and below 0.5 m in the hight of wave. Using the these conditions, we can raise the test efficiency of many kinds firing tests and guarantee maritime safety. The number of the ships in approved sea area is entirely unrelated to visibility of the sea. The time period when the number of the ships are high on the sea is morning. The season when the number of the ships are comparatively high on the sea is fall. APG of ADD could raise the efficiency of the firing tests and improve the maritime safety, using the analysis results of the characteristics on the ship distribution.

• Journal of the Korean Ceramic Society
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• v.43 no.9 s.292
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• pp.544-551
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• 2006

The sealing technique between a glass tube and a copper heat pipe in an evacuated tube solar collector is studied. In this study two different sealing techniques, such as flame method and furnace firing, are examined. After the sealing of a copper to a glass, the oxidation state of the copper and its bonding morphology were examined by SEM and XRD. Its oxidation was retarded by coating of borate solution on the copper, and $Cu_2O(cuprite)$ turned into CuO(tenorite) with increase in a firing temperature and firing time. Porous structure was found in the oxide layer when CuO formed. The best sealing morphology was observed when the thickness of the oxidation layer was less than $20{\mu}m$. The sealing technique performed in a furnace was promising and the satisfactory result was obtained when the sample was fired at $950^{\circ}C$ for 5 min under $N_2$ atmosphere. Annealing procedure is recommended to remove the stress left at the bonding zone.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2006.10a
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• pp.4-5
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• 2006

This paper represents modeling and optimization techniques for solar cell process on single-crystalline float zone (FZ) wafers with high efficiency; There were the four significant processes : i)emitter formation by diffusion, anti-reflection-coating (ARC) with silicon nitride using plasma-enhanced chemical vapor deposition (PECVD); iii)screen-printing for front and back metallization; and iv)contact formation by firing. In order to increase the performance of solar cells, the contact formation process is modeled and optimized. This paper utilizes the design of experiments (DOE) in contact formation to reduce process time, fabrication costs. The experiments were designed by using central composite design which is composed of $2^4$ factorial design augmented by 8 axial points with three center points. After contact formation process, the efficiency of the solar cell is modeled using neural networks. This model is used to analyse the characteristics of the process, and to optimize the process condition using genetic algorithms (GA). Finally, find optimal recipe for solar cell efficiency.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.6
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• pp.832-840
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• 2019

Recently, pollution from gunpowder due to shell shootings at military drilling sites has raised various environmental concerns. The purpose of this study is to predict the contamination level of RDX in the soil area of the firing range zone near Anwol river watershed, the study site, and the intake area, Anwol river and Imjin river, as a function of time and space. In this study, a multimedia model was developed to predict the variation of RDX contamination by rainfall. The range of the medium was limited to soil, water, and sediment, and excluded the atmosphere, taking into account the physical and chemical properties of RDX with low vapor pressure and low Henry's constant. The pollutant levels of the waters of compartments, including the last section of the Imjin River affecting the water intake, was compared with the environmental standard for RDX.

• Journal of the Korean Ceramic Society
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• v.24 no.2
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• pp.161-169
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• 1987

An experimental study of the characteristics and the behavior of flames, and the aerodynamic flow pattern was carried out in the present work on a down draft kiln for gas firing. The aim of this work is to establish a behavior of flames and to know the extent to which the flow pattern is affected by the height of baffle plate. The measurements of temperature, concentrations of fuelgas, and kiln pressure were conducted at different temperature in kiln, and at different height of baffle plate. From the obtained results, it was found that the characteristics of thestagnation zone are greatly affected when changing over the height of baffle plate, and the best condition of that was 115m/m.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.1-9
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• 2020

Using kerosene and liquid oxygen, 1.5-tonf class liquid-liquid pintle injector with rectangular two-row orifice was designed and manufactured. The combustion test of the pintle injector was carried out to verify the combustion performance and combustion stability under a supercritical condition which is the actual operation condition of the liquid rocket engine. The combustion test result showed that the pintle tip was damaged by the high temperature combustion gas in the high-mixed ratio recirculation zone of the combustion chamber. To solve this problem, the insert nozzle was installed in the pintle injector to increase cooling performance at the pintle tip. As a result of the hot firing test, installation of the insert nozzle, AR and BF had a great effect on pintle tip cooling performance.