• Journal of the Korean Chemical Society
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• v.48 no.3
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• pp.229-235
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• 2004

For the study of hydrogen bonding phenomenon of high energetic compounds, we have been carried out a theoretical calculations for the nitromethane with the program Gaussian-98. The calculations at levels of restricted BLYP/6-311++G(d,p), B3LYP/6-311++G(d,p) and MP2/6-311++G have been performed to obtain molecular structures, hydrogen bonding effects and vibrational spectra of nitromethane monomer and dimer. The results show nitromethane is favored to make two hydrogen bonds between molecules and the nitromethane dimer is more stable than the monomer about 15.2, 19.4 and 32.6 kJ/mol for the BLYP, B3LYP, and MP2 level calculations, respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.456-461
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• 2017

In this study, the rheological properties of nitromethane gel propellants on nano/micron sized gelling agent are investigated. Silicon dioxide is used as the gellant with 5 wt%, 6.5 wt% and 8 wt% concentration, respectively, where the measurements are conducted under steady-state shear flow conditions using a rotational rheometer. The nitromethane/silicon dioxide gel showed non-Newtonian flow behavior for the entire experimental shear rate ranges. The gel fuels with nano-sized gellant had a slightly higher viscosity than the gel fuels with micron-sized one for low shear rate range. Additionally, it was found that Herschel-Bulkley model can hardly describe the rheological behavior of nitromethane gel propellant, but the NM model(by Teipel and Forter-Barth) is better suited to explain the rheological behavior of nitromethane gel propellant.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.659-668
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• 2006

The optimization of supercritical water oxidation (SCWO) process for decomposing nitromethane was studied by means of a design of experiments. The optimum operating region for the SCWO process to minimize COD and T-N of treated water was obtained in a lab scale unit. The authors had compared the results from a SCWO pilot plant with those from a lab scale system to explore the problems of scale-up of SCWO process. The COD and T-N in treated waters were selected as key process output variables (KPOV) for optimization, and the reaction temperature (Temp) and the mole ratio of nitromethane to ammonium hydroxide (NAR) were selected as key process input variables (KPIV) through the preliminary tests. The central composite design as a statistical design of experiments was applied to the optimization, and the experimental results were analyzed by means of the response surface method. From the main effects analysis, it was declared that COD of treated water steeply decreased with increasing Temp but slightly decreased with an increase in NAR, and T-N decreased with increasing both Temp and NAR. At lower Temp as $420{\sim}430^{\circ}C$, the T-N steeply decreased with an increase in NAR, however its variation was negligible at higher Temp above $450^{\circ}C$. The regression equations for COD and T-N were obtained as quadratic models with coded Temp and NAR, and they were confirmed with coefficient of determination ($r^2$) and normality of standardized residuals. The optimum operating region was defined as Temp $450-460^{\circ}C$ and NAR 1.03-1.08 by the intersection area of COD < 2 mg/L and T-N < 40 mg/L with regression equations and considering corrosion prevention. To confirm the optimization results and investigate the scale-up problems of SCWO process, the nitromethane was decomposed in a pilot plant. The experimental results from a SCWO pilot plant were compared with regression equations of COD and T-N, respectively. The results of COD and T-N from a pilot plant could be predicted well with regression equations which were derived in a lab scale SCWO system, although the errors of pilot plant data were larger than lab ones. The predictabilities were confirmed by the parity plots and the normality analyses of standardized residuals.

• 월간산업보건
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• s.204
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• pp.23-25
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• 2005

• 월간산업보건
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• s.208
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• pp.35-36
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• 2005

• 월간산업보건
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• s.207
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• pp.20-22
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• 2005

• 월간산업보건
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• s.205
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• pp.20-22
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• 2005

• 월간산업보건
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• s.206
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• pp.20-22
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• 2005

• Bulletin of the Korean Chemical Society
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• v.21 no.7
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• pp.685-689
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• 2000

The complexation reaction between Pb2+,TI and Cd2+ions and macrocyclic ligands, 18-crown-6 ( 18C6) and dibenzo- 18-crown-6 (DB 18C6), was studied in dimethylsulfoxide (DMSO)-nitromethane (NM) and dimethyl-formamide (DMF)-nitromethane binary system s by square wave polarography (SWP) technique. The stoichiometry and stability of the complexes were determined by monitoring the shifts in half-waves or peak potentials of the polarographic waves of metal ions against the Iigand concentration. In most cases, the stability constants of complexes increase with increasing amounts of the nitromethane in mixed binary solvents used in this study. The complexes formed between 18C6 and DB18C6 and these metal cations in all cases had a stoichiometry of 1 : 1. The results obtained show that there is an inverse relationship between the formation constant of complexes and the donor number of solvents based on a Gatmann donocity scale and the stability constants show a high sensitivity to the composition of the mixed solvent systems. A linear behavior was observed for variation of log Kf of I8C6 complexes vs the composition of the mixed solvent systems in NM/DMSO and NM/DMF,but a non-linear behavior was observed in the case of DB 18C6 complexes in these binary systems. In most of the systems investigated, the Pb2+ cation forms a more stable complex with the 18C6 than other two cations and the order of selectivity of this Iigand for cations is: Pb2+ > TI+,Cd2+.

• Membrane Journal
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• v.3 no.3
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• pp.136-139
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• 1993

It is well known that the membrane permeation in pervaporation is governed by both the chemical nature of the membrane material and the physical structure of the membrane and also the separation can be achieved by differences in either solubility, size or shape. The solubility of the penerrant in the polymeric membrane can be described qualitively by applying the Hildebrand relation [1] which relates the energy of mixing of the penerrant and the polymer material. Froehling et al. have tried to predict the swelling behavior of polymers for the systems of polyvinylchloride(PVC)-toluene-methanol, PVC-trichloroethylene-nitromethane and PVC-n-butylacetate-nitromethane[2]. The former two systems which do not show the donor/acceptor interactions upon mixing showed the successful results[2]. In addition to this technique, there are several other possible approaches to predict the swelling behaviors of polymers, such as the surface thermodynamic approach[3, 4], the comparison of the membrane polarity with the solvent polarity in terms of Dimroth's solvent polarity value[5].