• Title/Summary/Keyword: explosives

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A Study on Remediation of Chlorinated Hydrocarbons and Explosives using Pulsed-UV System (Pulsed-UV 시스템을 이용한 염소계 유기화합물 및 화약류 제거에 관한 연구)

  • Lee, Han-Uk;Han, Jonghun;Yoon, Yeomin;Lee, Jongyeol;Her, Namguk
    • 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.

Numerical investigation of the impact of geological discontinuities on the propagation of ground vibrations

  • Haghnejad, Ali;Ahangari, Kaveh;Moarefvand, Parviz;Goshtasbi, Kamran
    • Geomechanics and Engineering
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    • v.14 no.6
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    • pp.545-552
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    • 2018
  • Blast-induced ground vibrations by a significant amount of explosives may cause many problems for mining slope stability. Geological discontinuities have a significant influence on the transmission of dynamic pressure of detonation and according to their position relative to the slope face may have damaging or useful impacts on the slope stability. In this study, the effect of geological discontinuities was investigated by modelling a slope with geological discontinuities through applying the dynamic pressure in three-dimensional discrete element code (3DEC). The geological discontinuities in four states that generally apperceived in mine slopes are considered. Given the advantages of the pressure decay function defined by some researcher, this type of function was used to develop the pressure-time profile. The peak particle velocities (PPV) values were monitored along an axis by utilization of Fish programming language and the results were used as an indicator to measure the effects. As shown in the discontinuity-free model, PPV empirical models are reliable in rocks lacking discontinuities or tightly jointed rock masses. According to the other results, the empirical models cannot be used for the case where the rock mass contains discontinuities with any direction or dip. With regard to PPVs, when the direction of discontinuities is opposite to that of the slope face, the dynamic pressure of detonation is significantly damped toward the slope direction at the surface of discontinuities. On the other hand, when the discontinuities are horizontal, the dynamic pressure of detonation affects the rock mass to a large distance.

A Study of Explosive Jet-cutting Technology by Linear Shape Charges (성형폭약에 의한 폭발절단기술에 관한 연구)

  • 이병일;박근순;공창식;김광태
    • Tunnel and Underground Space
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    • v.10 no.4
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    • pp.516-525
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    • 2000
  • Recently, the demand for pollution-free demolition work of old reinforced concrete and steel structure has rapidly increased as the redevelopment of urban area has been accelerated. This study deals with linear shape charges for explosive jet cutting on steel structure. We have tested material and shape of steel structure, characteristics of thickness and strength, shape of linear shape charges, type of shape charges, cumulative charges, type of liner, stand-off distance, detonation method. effect of sound and vibration by air blast in explosive jet cutting method. So, We developed linear shape charges in order to take advantage of optimum explosive jet cutting condition. Shape charges were made of PETN explosives. We obtained the experimental formula to decide the amount of explosive needed for thickness of steel structure plate. There are prospects for application of the explosion curving technology under the open space conditions for dismantling the steel structure and steel bridge, scrapped old boats, which are going out of service.

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Dye Removal by Phlebia tremellosa and Lignin Degrading Enzyme Transformants (아교버섯(Phlebia tremellosa)의 리그닌 분해효소 형질전환체를 이용한 염료의 탈색)

  • Kum, Hyun-Woo;Ryu, Sun-Hwa;Lee, Sung-Suk;Choi, Hyoung-T.
    • Korean Journal of Microbiology
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    • v.46 no.1
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    • pp.93-95
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    • 2010
  • White rot fungi which have lignin degrading enzymes show high degrading activity to diverse recalcitrant compounds such as polycyclic aromatic compounds, dyes, explosives and endocrine disrupting chemicals. We have examined decolorizing activity of dyes by Phlebia tremellosa and two transformants which had genetically transformed using laccase or manganese peroxidase (MnP) gene. In case of methyl green, wild type strain showed 50% decolorization while laccase transformant (TF2-1) and MnP transformant (T5) showed more than 90% decolorization on day 3. Remazol brilliant blue R(RBBR) was decolorized up to 85% by two transformants while the wild type showed 67% decolorization on day 3. Transformants TF2-1 and T5 both showed increased laccase and MnP activity respectively during the whole growing phase.

In-hole seismic method for measuring dynamic properties of soils (지반물성치 측정을 위한 인흘탄성파시험)

  • Mok Young Jin;Kim Young Su;You Chang Yeon;Han Man Jin
    • 한국지구물리탐사학회:학술대회논문집
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    • 2005.09a
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    • pp.117-123
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    • 2005
  • An in-hole seismic tests, which has been developed for measuring dynamic properties of soils and rock mass, is a bore hole seismic method that has cost effectiveness and practicality. The upgraded features include the motorized triggering system rather than the manual prototype version in the previous studies and a damper between source and receiver in the module. The performance of the probe has been verified through extensive cross-hole tests and in-hole tests at various sites. The dynamic stiffness of subsurface materials and rock mass have been evaluated and recently, the measurement of shear wave velocity was successfully adopted at horizontal holes of tunnel-face to install explosives. So the application of in-hole seismic test for various soil materials was certified.

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The Characteristics of the Output Voltage Ferroelectrics for High Voltages Pulse Generators (고전압 펄스 발생기를 위한 강유전체의 전압 출력 특성)

  • Jang, Dong-Gwan;Choi, Sun-Ho;Hwang, Sunl-Mook;Huh, Chang-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.10
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    • pp.1408-1412
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    • 2013
  • High power pulse generating technology is to accumulate the energy for relatively long and then to create a strong force by emitting the energy very fast. High power pulse generating technology has recently been using in various fields like environments, industry, research, military and so on. Numerous studies about high power pulse generators have already been performed and commercialized in various conditions. However, in aspect of their size and weight, it is hard to carry the generators which currently have been developed. For these reasons, din nations like America or Russia, the researches have been performed for Ferroelectric Generators(FEG), which have relatively simple structure and are economical. To realize the ferroelectric generator, in this study, we selected the PZTs which have different physical properties respectively, and then shocked them using explosives. The PZT samples with volumes of $0.31{\sim}0.94cm^3$ were depolarized by shocked and produced the waveform that have peak voltages of 4.28 ~ 15kV. The lowest relative permittivity sample generated much higher peak voltage. And sudden voltage drops which seem to be caused by dielectric breakdown were observed in some experiments using low young's modulus samples. Also, increase in thickness led to increase in peak voltage, but the ratio of the voltage rise did not reach the ration of the thickness increase.

A Sporolactobacillus-, Clostridium-, and Paenibacillus- Dominant Microbial Consortium Improved Anaerobic RDX Detoxification by Starch Addition

  • Khan, Muhammad Imran;Yoo, Keunje;Kim, Seonghoon;Cheema, Sardar Alam;Bashir, Safdar;Park, Joonhong
    • Journal of Microbiology and Biotechnology
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    • v.30 no.6
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    • pp.839-847
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    • 2020
  • In the present study, an anaerobic microbial consortium for the degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was selectively enriched with the co-addition of RDX and starch under nitrogen-deficient conditions. Microbial growth and anaerobic RDX biodegradation were effectively enhanced by the co-addition of RDX and starch, which resulted in increased RDX biotransformation to nitroso derivatives at a greater specific degradation rate than those for previously reported anaerobic RDX-degrading bacteria (isolates). The accumulation of the most toxic RDX degradation intermediate (MNX [hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine]) was significantly reduced by starch addition, suggesting improved RDX detoxification by the co-addition of RDX and starch. The subsequent MiSeq sequencing that targeted the bacterial 16S rRNA gene revealed that the Sporolactobacillus, Clostridium, and Paenibacillus populations were involved in the enhanced anaerobic RDX degradation. These results suggest that these three bacterial populations are important for anaerobic RDX degradation and detoxification. The findings from this work imply that the Sporolactobacillus, Clostridium, and Paenibacillus dominant microbial consortium may be valuable for the development of bioremediation resources for RDX-contaminated environments.

The influences of encircling gill net fishery on fish organisms (선자망어업이 어업생물에 미치는 영향)

  • HAN, Inwoo;YOON, Euna;OH, Wooseok;LEE, Kyounghoon
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.53 no.1
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    • pp.41-48
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    • 2017
  • Encircling gill net fishery is a kind of gill net which is generally used in shallow coastal waters. After the fish have been encircled by the gill net, noise stimulus such as a stone or sound is used to force them to gill or entangle themselves in the netting surrounding them. Although the fishing by a stone is a traditional fishing method, it is considered as an illegal fishing method by physical stimulus such as explosives and mechanical vibrator. However, this illegal fishing method has raised some problems to the fishing boat of other fisheries or many anglers due to disturb aggregating fish schools. This study is aimed to provide scientific base data to verify whether to impact the ecosystem caused by this encircling gill net. This study exhibited that the impulse noise by concrete sphere in the encircling gill net was $159dB/{\mu}Pa$, the ambient noise from ship engine was $160dB/{\mu}Pa$, and the maximum noise from continuous artificial vibrator was $175dB/{\mu}Pa$. These may be stimulus to the escape of fish distributed in a wide area in its natural state; it is not likely the cause of death due to catastrophic stress. Therefore, it needs to prepare the consideration of standard limit on fishing stimulus in fishing methods of the fishery laws and regulations, prevent fishermen form using illegal fishing gear (i.e. explosive sound standards: $200{\sim}220dB/{\mu}Pa$ and provide them with countermeasures.

Determination of allyl isothiocyanate, capsaicin and dihydrocapsaicin in pungent liquid samples (자극성 액체시료 중 Allyl Isothiocyanate, Capsaicin and Dihydrocapsaicin 정량에 관한 연구)

  • Kim, Sang-Soo;Choi, Jong-Moon
    • Analytical Science and Technology
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    • v.26 no.1
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    • pp.73-79
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    • 2013
  • The allyl isothiocyanate, capsaicin and dihydrocapsaicin as main components in self defense sprays were determined by gas chromatography-mass spectrometer (GC-MS). Although self defense spray was used to protect by myself, a social problem could be caused by the hazard of spray chemical due to use pungent liquid. To identify this, the pH of pungent liquid solutions, solubility to detergents, the existence of other materials and the types and amounts of pungent material in spray chemicals were investigated in this work. Finally, the amounts of allyl isothiocyanate, capsaicin and dihydrocapsaicin as pungent materials in them were determined by GC-MS. The pH of chemicals were about 5.7 as weak acid, the detergents can emulsify them with water well. And they did not contain fluorescent materials and hazard organic solvents. The pungent components in three real samples were only allyl isothiocyanate [47,600 mg/kg (47.6%)] in one sample, and mixtures with capsaicin [228 mg/kg~368 mg/kg (1.14%~1.84%)] and dihydrocapsaicin [224 mg/kg~414 mg/kg (1.12%~2.07%)] in the others, respectively.

Process variables of gamma-type aluminum trihydride in wet chemical synthesis (감마형 삼수소 알루미늄 습식합성반응의 공정변수 연구)

  • Yang, Yo-Han;Kim, Woo-Ram;Gwon, Yoon-Ja;Park, Mi-Jeong;Kim, Jun-Hyung;Cho, Young-Min
    • Journal of the Korean Applied Science and Technology
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    • v.35 no.1
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    • pp.214-222
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    • 2018
  • Alane(aluminum trihydride, $AlH_3$) is a candidate material involving high energetic capacity for solid propellant or explosives. In this study aluminum trihydride-etherate ($AlH_3{\cdot}(C_2H_5)_2O$) was synthesized through a wet process, and solid alane was extracted by controlled crystallization. Alane crystals were grown during the crystallization step with phase conversion of aluminum trihydride-etherate to alane using an anti-solvent. Stable crystal forms were found by a 2 hour crystallization process at $85^{\circ}C$. Finally the extracted solid aluminium trihydride consisted mainly of ${\gamma}-type$ with $50-100{\mu}m$ in size.