• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.91-97
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• 2005

The research on the explosive limits is one of fundamental fields of combustion process, and information on the explosive limits of mixture of fuel and oxidant, with or without additives, is very important for the prevention in industrial fire and explosion accidents. Explosive limits of all compounds and solvent mixtures can be calculated with the appropriate use of the fundamental laws of Raoult, Batten, Le Chatelier and MRSM(modified response surface methodology) model. In this study, the reference values of lower explosive limits(LEL) of the ethanol+toluene+ethylacetate system were compared with the calculated values by using the solution thermodynamics and the MRSM model, respectively. The values calculated by the proposed equations were a good agreement with literature data within a few percent. By means of this methodology, it is possible to evaluate reliability of experimental data of the lower explosive limits of the flammable mixtures. Also, from given results, it is possible to predict explosive limits of the other flammable liquid mixtures used in the chemical process by the use of the proposed equations.

• Journal of Soil and Groundwater Environment
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• v.18 no.1
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• pp.78-84
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• 2013

This study was conducted in order to evaluate the removal process for long-term contamination sources including chlorinated hydrocarbons (TCE and PCE) and explosive compounds (TNT, RDX, and HMX) in underground water using a pulsed-UV system. Crystallized cells containing the contaminants were placed 10, 20, and 40 cm away from a lamp that emits pulsed-UV rays in order to examine how the removal efficiency is influenced by the distance between the source of the light and the compounds. Chlorinated hydrocarbons were completely removed in 30 minutes with a distance of 10 cm, while PCE was completely removed even with a distance of 20 cm. In the case of explosive compounds, removal efficiencies slightly varied depending on the compounds. The majority of the compounds were perfectly removed with a contact time of 10 minutes. In particular, for RDX, the results showed that complete removal was obtained within one minute, regardless of the distance from the UV source. The amount of light energy is in inverse proportion to the distance, and thus the energy reaching the compounds severely diminishes as the distance increases. Therefore, the removal efficiency decreased with increasing distance in the system.

• 한국가스학회:학술대회논문집
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• 1999.09a
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• pp.203-208
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• 1999

• Journal of Soil and Groundwater Environment
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• v.17 no.6
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• pp.119-128
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• 2012

The applicability and accuracy of Revised Universal Soil Loss Equation (RUSLE) model on the estimation of soil loss at impacted area of shooting range was tested to further the understanding of soil erosion at shooting ranges by using RUSLE. At a shooting range located in northern Kyunggi, the amount of soil loss was estimated by RUSLE model and compared with that estimated by Global Positioning System-Total Station survey. As results, the annual soil loss at a study site (202 m long by 79 m wide) was estimated to be 2,915 ton/ha/year by RUSLE and 3,058 ton/ha/year by GPS-TS survey, respectively. The error between two different estimations was less than 5%, however, information on site conditions should be collected more to adjust model coefficients accurately. At the study shooting range, sediments generated by rainfall was transported from the top to near the bottom of the sloping face through sheet erosion as well as rill erosion, forming a gully along the direction of the storm water flow. Coarser fractions of the sediments were redeposited in the limited area along the channel. Distribution characteristics of explosive compounds in soil before and after summer monsoon rainfall in the study area were compared with the erosion patterns. Soil sampling and analyses results showed that the dispersion of explosive compounds in surface soil was consistent with the characteristics of soil erosion and redeposition pattern of sediment movements after rainfalls.

• Journal of Soil and Groundwater Environment
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• v.20 no.6
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• pp.73-84
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• 2015

Nine plant species were selected through vegetation survey at three military shooting ranges at northern Gyeonggi Province. Plants were germinated in normal soil and three seedlings were transplanted to a bottom sealed pot containing sandy loam soils contaminated with either RDX (291 mg/kg) or TNT (207 mg/kg). Planted, blank (without plant), and control (without explosive compound) pots were grown in triplicate at a green house for 134 days. During cultivation, transplanted plants exhibited chlorosis and necrosis in flower and leaf by explosive toxicity and stress. Only three plants, Wild soybean, Amur silver grass, Reed canary grass, survived in TNT treated pot, while seven plant species except for field penny cress and jimson weed, thrived in RDX treated pot. Appreciable amount of TNT (61.6~241.2 mg/g-D.W.) was detected only in plant roots. Up to 763.3 mg/g-D.W. along with 4-amino-2,6-dinitrotoluene, an intermediate of TNT, accumulated in the root of wild soybean. In addition, azoxy compounds, abiotic intermediates of TNT, were detected in TNT treated soils. RDX absorbed average 1,839.95 mg/kg in shoot and 204.83 mg/kg in root. Most of TNT in plant was accumulated in underground part whereas RDX was localized in aerial part. Material balance calculation showed that more than 95% of the initial TNT was removed in the planted pots whereas only 60% was removed in the blank pot. The amount of RDX removed from soil was in the order of Amur Silver Grass (51%) > Chickweed (43%) > Evening primrose (38%). Based on the results of pot cultures, Amur silver grass and Reed canary grass are selected as tolerant remedial plants for explosive toxicity.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.123-126
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• 2006

Reduction kinetics and intermediates behaviour of three high explosives (HMX, RDX, and TNT) were studies in batch reactors using either nano or micro size zero valent iron(ZVI) as reducing agent. The kinetics constants normalize to the mass of iron($k_M$) or to the surface area ($k_{SA}$) were measured and compared along with the changes of intermediate concentrations of each explosive. Results showed that $k_M$ and $k_{SA}$ values neither correlated each other nor explained the behaviour of intermediates of each high explosive in the batch reactor, in which initial intermediates decreased rapidly with nano ZVI treatment whereas the intermediates accumulated and stayed longer in the micro ZVI treated reactor.

• Journal of Soil and Groundwater Environment
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• v.14 no.1
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• pp.51-60
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• 2009

A series of experiments was performed to develop an optimized analytical procedure for the analysis of explosives in soil by HPLC with soil samples collected at two live-fire military shooting ranges. The minimum amount of soil to be collected, Wmin, for the analysis of explosive compounds was 125g, based on the segregation and homogeneity constants that account for soil heterogeneity and non-homogeneous distribution of target explosive compounds. The optimization of extraction and HPLC analytical conditions were also studied based on analytes CV values. The most effective soil/ extractant ratio was estimated to be 10g-pretreated soil/20 mL acetonitrile as extractant. The optimized HPLC elution conditions for the separation of US EPA designated 14 explosive compounds, were column temperature 30${\circ}C$, eluents ratio of isopropanol: acetonitrile: water = 18 : 12: 70, and flow rate of 0.8 mUmin at 230 nm. However, UV wavelength 254 nm was better for the analysis of NB, 2,4-DNT, 2NT, 4NT, and 3NT.

• Analytical Science and Technology
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• v.10 no.5
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• pp.325-331
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• 1997

Among various CE separation methods, micellar electrokinetic capillary chromatography(MECC) method using sodium dodecylsulfate(SDS) provides rapid and accurate separation of organic explosive constituents with easy. The running buffer was composed with 2.5 mM borate and 25mM SDS(pH 8.5). Addition of 1M urea and 10% organic modifiers (acetonitrile, methanol and ethanol) improves the resolution of adjacent explosive constituents. When 15 explosive constituents were developed in MECC, most constituents were separated successively while RDX/TNB and DNN/DEP were not, and detection limits of separated compounds are in range of 1 to 4 ppm.

• Journal of the Korean Society for Heat Treatment
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• v.34 no.2
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• pp.66-74
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• 2021

Cladding material, which can selectively obtain excellent properties of different metals, is a composite material that combines two or more types of dissimilar metals into one plate. The titanium-copper cladding material between titanium which has excellent corrosion resistance and copper which has high thermal and electrical conductivity, are highly valuable composite materials. It can be used as heat exchangers with high conductivity under severe corrosion conditions. In order to apply the clad plate to the heat exchanger, it must be manufactured in the form of a tube and additional welding is required. It is important to select the cladding material manufacturing process and the welding process. The process of manufacturing the cladding material includes extrusion, rolling, and explosive bonding. Among them, the explosive bonding process is suitable for additional welding because no heat-affected zone is formed. In this study TIG welding of the explosive-bonded dissimilar clad plates was successfully performed by butt welding. The microstructures and bonding interface of the welded part were observed, and the effect of the bonding layer at the welding interface and the intermetallic compounds on the mechanical properties and tensile plastic deformation behaviors were analyzed. And also the integrity of TIG-welded dissimilar part was evaluated.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.90.1-90.1
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• 2013

Nature utilizes various of the colorization process. Some species of birds can express their mood of tempers by changing their collagen structures on skin. For example, turkey can change their skin color by expansion of the collagen structures, which are associated with the distinct color changes. Here, we developed bioinspired virus-based colorimetric sensors which can be genetically tuned for target molecule. Using M 13 bacteriophage, we fabricated responsive self-assembled color matrices composed of quasi-ordered fiber bundle structures. These virus matrices can exhibit color change by stimuli through fiber bundle structure modulation. Upon exposure of volatile organic compounds, the resulting multi-colored matrices exhibited distinct color changes with different ratios that can be recognized by the naked eyes. Using the directed evolutionary approaches, we genetically engineered the virus matrix to incorporate binding motif for explosive detection (i.e., trinitrotoluene (TNT)). Through utilizing a common handheld device (i.e., iPhone), we could distinguish TNT molecules down to 20 ppb in a selective manner. Our novel biomimetic virus colorimetric sensor can overcome current limitation for low response selectivity.