• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.1
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• pp.41-47
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• 1999

The burning rate of solid propellant is one of the key parameter associated with the dynamic characteristics of combustion and the combustion performances. In the AP propellants, the evaporation on the reacting surface as well as the decomposition of the propellant is of great importance in determining the overall burning rate. In this study, a theoretical analysis was conducted to obtain the expression for burning rate in the steady state combustion with the energy and species equations in the condensed phase when the radiative heat flux partially contributes to the total heat transfer to the propellant surface.

• Journal of the Korean Mathematical Society
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• v.40 no.6
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• pp.1061-1074
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• 2003

We first show the analyticity of Stokes operator in Besov spaces $B_{p,q}$$^{a}$ ( $R_{＋}$$^{n}$). Then, we estimate the asymptotic behavior of the Stokes solutions. We also show the Hodge decomposition.n.

• Journal of environmental and Sanitary engineering
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• v.15 no.2
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• pp.49-57
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• 2000

The objective of this study is to find solid waste decomposition in landfill without leachate discharge. This study was observed variation of landfill gas production rate and leachate for stabilization assessment, and using four sets of lysimeter as experimental apparatus. Soild waste decomposition was accelerated in without leachate discharge system by sufficient moisture for methane bacteria. And gas production rate was between 54.2ℓ/kg VS∼335.9ℓ/kg VS in each lysimeter. Generation time of methane gas was showed different in each lysimeter, but it was much faster than literature research. The time of stabilization phase were began as follows : L-1 400 day, L-2 350 day, L-3 170 day and L-4 70 day respectively. Decreasing times of BOD/COD ratio and C/N ratio were necessary more than literature research because organic matter was not discharge such as wash out.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.1
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• pp.81-85
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• 2012

This work is related to study the thermal decomposition of 1,3,5-trinitro-1,3,5-triazacylohexane(RDX) by differential scanning calorimeter and thermo-gravimetry with Kissinger's & Iso-conversional method under nonisothermal conditions, with heating rate from 2 to $8^{\circ}C$/min or given heating rate. We calculated and compared activation energy with these two methods. Iso-conversional method is better than Kissinger's method to study decomposition mechanism. We also investigated activation energy and frequency factor by Kissinger's & Iso-conversional method with the influence of particle size. In case of single crystal, Cl-3(large crystal) has better thermal stability than Cl-5(small crystal). The activation energy increased according to the size of the particle size.

• Environmental and Resource Economics Review
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• v.9 no.3
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• pp.489-513
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• 2000

This paper introduces a new method to estimate and decompose sources of carbon dioxide emissions using an input-output model with decomposition method free of residual usually associated with this kind of analysis. This method is different from others, using what we call 'mean rate-of-change index (MRCI)' for weights of the decomposed terms. Ang et al.(1998) asserted that logarithmic mean divisia index(LMDI) is superior to Laspeyres index(LI) or simple average divisia index(SADI) since it reduces residual to zero. We claim that our method is an improvement over the other methods because it enables residual free decomposition even when data contain negative values, the case which LMDI cannot handle. We demonstrate by way of showing some examples that our method is superior to LI, SADI(Proops, 1993 and Chung, 1998) or LMDI(Ang et al., 1998).

• Textile Coloration and Finishing
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• v.13 no.4
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• pp.264-271
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• 2001

Catalytic wet oxidation of ethylene glycol as refractory compound was studied in a batch slurry reactor using lwt% $Pt/A1_2O_3$, lwt% $Pt/TiO_2,\;Mn/CeO_2$(1:1) and 5wt% $Mn/Al_2O_3$. Experiments were conducted to investigate theeffects of temperature, initial ethylene glycol concentration, catalyst dosage and PH on the ethylene glycol decomposition. When compared with the uncatalyzed reaction, the use of catalysts could increase the rate of ethylene glycol decomposition. The lwt% $Pt/A1_2O_3$ catalyst was preferable to the other catalysts for the destructive oxidation of ethylene glycol. The reaction rate was first order with respect to initial concentration of ethylene glycol. In acidic condition the removal efficiency of ethylene glycol was good, but there was a significant leaching of platinum. Small amount of acetic acid, oxalic acid, masonic acid and formic acid as intermediates were detected during catalytic wet air oxidation of ethylene glycol.

• Journal of the Korean Society of Safety
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• v.11 no.4
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• pp.79-83
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• 1996

In this study, in attempt to develop a new application technique of discharge plasma, we employed a kind of discharging method called SPCP ( short for Surface discharge induced Plasma Chemical Process). Applications of SPCP have been widely used for years. Compact ozonizers to deodorize household equipments like refrigerators we a part of such applications. We took advantages of the compactness and durability of the SPCP electrode to set up an experimental apparatus for decompositing vapor of aromatic hydrocarbons such as toluene, benzene and xylenes, which are major substances given off In painting or washing processes and aggravate working conditions. Results obtained from this study are summarized as follows. 1) Aromatic hydrocarbon vapors of up to 2,000ppm were almost thoroughly decomposed at the flow rate of 4ℓ/min or lower under the discharge with electric power of 400 Watts. 2) In dry air, as the decomposition progresses, tar-like substance deposits on the discharging areas, which deteriorated the decomposition rate in the end. This substance, however, was almost thoroughly removed by keeping discharge in dry air containing no solvent vapor.

• Journal of Environmental Science International
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• v.22 no.1
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• pp.83-89
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• 2013

Silicon carbide with aluminium oxide was used to remove the sulphur hexafluoride ($SF_6$) gas using microwave irradiation. The destruction and removal efficiencies (DREs) of $SF_6$ were studies as a function of various decomposition temperatures and microwave powers. The decomposition of $SF_6$ gas was analyzed using GC-TCD. XRD (X-ray powder diffraction) and XRF (X-ray Fluorescence Spectrometer) were used to characterize the properties of aluminum oxide. DREs of $SF_6$ were increased as the microwave powers were increased. Additive aluminium oxide on SiC increased the removal efficiencies and decreased the decomposition temperature. The XRD results show that the ${\gamma}-Al_2O_3$ was transformed to ${\alpha}-Al_2O_3$ during $SF_6$ decomposition by microwave irradiation. It was found that the best material to control $SF_6$ was SiC with $Al_2O_3$ 30 wt% in consideration of microwave energy consumption and $SF_6$ decomposition rate.

• Nuclear Engineering and Technology
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• v.41 no.10
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• pp.1275-1284
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• 2009

A directly heated $SO_3$ decomposer for the sulfur-iodine and hybrid-sulfur processes has been introduced and analyzed using the computational fluid dynamics (CFD) code CFX 11. The use of a directly heated decomposition reactor in conjunction with a very high temperature reactor (VHTR) allows for higher decomposition reactor operating temperatures. However, the high temperatures and strongly corrosive operating conditions associated with $SO_3$ decomposition present challenges for the structural materials of decomposition reactors. In order to resolve these problems, we have designed a directly heated $SO_3$ decomposer using RA330 alloy as a structural material and have performed a CFD analysis of the design based on the finite rate chemistry model. The CFD results show the maximum temperature of the structural material could be maintained sufficiently below 1073 K, which is considered the target temperature for RA 330. The CFD simulations also indicated good performance in terms of $SO_3$ decomposition for the design parameters of the present study.

• Journal of the Korean Professional Engineers Association
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• v.14 no.1
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• pp.22-29
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• 1981

This study concernes the decomposition of cyanide ion in electroplating plant wastewater and COD variation of photodeveloping wastewater under various conditions. Determinations of CN- concentration were carried out by AgNO$_3$ titration method. The sample solutions were pretreated by passing ozone and decompositions were checked as a function of time for ozone treatment. Analysis of film developing wastewater was carried out by KMnO$_4$ method. Electroplating plant wastewater was also examined at various pH; decomposition rate of cyanide ion was found to increase at higher pH. Time required for the decomposition could be shortened by removing the heavy metal ions under alkaline condition. The effect of temperature on decomposition was studied at 40$^{\circ}$ and 60$^{\circ}C$. The result was better at 40$^{\circ}C$ although time for decomposition was almost same at both temperatures. Analysis of film developing wastewater revealed that COD decrease was faster during the first 1 to 2 hours. However, further decrease could not be effected. The existence of unknown special organics resistant to the decomposition was believed to be the reason.