A Predictive Study on Molecular and Explosive Properties of 1-Aminoimidazole Derivatives

조수경 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.7

Molecular structures and chemical properties of 1-aminoimidazole derivatives have been investigated at high levels of density functional theories. Heat of formation, density, explosive performances and impact sensitivities have been estimated at the global minimum of potential energy surface. As more nitro groups are introduced, the explosive performances of 1-aminoimidazole derivatives are enhanced, while the impact sensitivity becomes more sensitive. A two-dimensional plot between explosive performance and impact sensitivity has been utilized to comprehend the technical status of new explosive candidates. Based on locations in the two-dimensional plot, 1-aminodinitroimidzole isomers appears to have a potential to be good candidates for insensitive explosives, and 1-aminotrinitroimidazole may become a powerful explosive molecule whose behavior is quite close to HMX.

A Predictive Study on Molecular and Explosive Properties of 1-Aminoimidazole Derivatives

Cho, Soo-Gyeong Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.7

Molecular structures and chemical properties of 1-aminoimidazole derivatives have been investigated at high levels of density functional theories. Heat of formation, density, explosive performances and impact sensitivities have been estimated at the global minimum of potential energy surface. As more nitro groups are introduced, the explosive performances of 1-aminoimidazole derivatives are enhanced, while the impact sensitivity becomes more sensitive. A two-dimensional plot between explosive performance and impact sensitivity has been utilized to comprehend the technical status of new explosive candidates. Based on locations in the two-dimensional plot, 1-aminodinitroimidzole isomers appears to have a potential to be good candidates for insensitive explosives, and 1-aminotrinitroimidazole may become a powerful explosive molecule whose behavior is quite close to HMX.

Effect of one way reinforced concrete slab characteristics on structural response under blast loading

Kee, Jung Hun,Park, Jong Yil,Seong, Joo Hyun Techno-Press 2019 Advances in concrete construction Vol.8 No.4

In evaluating explosion-protection capacity, safety distance is broadly accepted as the distance at which detonation of a given explosive causes acceptable structural damage. Safety distance can be calculated based on structural response under blast loading and damage criteria. For the applicability of the safety distance, the minimum required stand-off distance should be given when the explosive size is assumed. However, because of the nature of structures, structural details and material characteristics differ, which requires sensitivity analysis of the safety distance. This study examines the safety-distance sensitivity from structural and material property variations. For the safety-distance calculation, a blast analysis module based on the Kingery and Bulmash formula, a structural response module based on a Single Degree of Freedom model, and damage criteria based on a support rotation angle were prepared. Sensitivity analysis was conducted for the Reinforced Concrete one-way slab with different thicknesses, reinforcement ratios, reinforcement yield strengths, and concrete compressive strengths. It was shown that slab thickness has the most significant influence on both inertial force and flexure resistance, but the compressive strength of the concrete is not relevant.

Rate-dependent hardening model for polymer-bonded explosives with an HTPB polymer matrix considering a wide range of strain rates

Park, Chunghee,Huh, Hoon,Park, Jungsu SAGE Publications 2015 Journal of composite materials Vol.49 No.4

<P>This article is concerned with the effect of the strain rate on the strain hardening behavior of polymer-bonded explosives at a wide range of strain rates ranging from 0.0001 s<SUP>–1</SUP> to 3870 s<SUP>−1</SUP>. Inert polymer-bonded explosive simulants are prepared as specialized particulate composites to acquire analogous mechanical characteristics to polymer-bonded explosives for safety reasons. Uniaxial compressive tests were conducted from quasi-static states to intermediate strain rates ranging from 0.0001 s<SUP>−1</SUP> to 100 s<SUP>−1</SUP> with cylindrical specimens using a dynamic material testing machine (INSTRON 8801) and a high-speed material testing machine. An experimental method was developed for uniaxial compressive tests at intermediate strain rates ranging from 10 s<SUP>−1</SUP> to 100 s<SUP>−1</SUP>. Split Hopkinson pressure bar tests were performed at high strain rates ranging from 1250 s<SUP>−1</SUP> to 3870 s<SUP>−1</SUP>. Deformation behavior was investigated using captured images from a high-speed camera. The strain hardening behavior of polymer-bonded explosive simulants was formulated as a function of the strain rate with the proposed rate-dependent hardening model based on the DSGZ model. The model is capable of representing the complicated strain rate effects on the strain hardening behavior for rate-sensitive materials with a second-order exponentially-increasing function of the strain rate sensitivity. The rate-dependent hardening model of polymer-bonded explosives can be readily applied to prediction of deformation modes of polymer-bonded explosives in a warhead that undergoes severe dynamic loads.</P>

Insensitive High Cyclotrimethylenetrinitramine (RDX) Nanostructured Explosives Derived from Solvent/Nonsolvent Method in a Bacterial Cellulose (BC) Gelatin Matrix

Qingping Luo,Chonghua Pei,Guixiang Liu,Yongjun Ma,Zhaoqian Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.3

Cyclotrimethylenetrinitramine (RDX) is an energetic material (EM) from the class of cyclic nitroamine explosive widely used in military applications because of its excellent integral properties. Using bacterial cellulose (BC) gelatin with a three-dimensional network as a matrix, N,Ndimethyllformamide (DMF) as the solvent of RDX, the RDX nanostructured explosives were prepared through the solvent/nonsolvent method. It was found that the solvent had a great impact on the crystallization of RDX in the solution and the RDX content in the nanostructured explosive. The RDX particles in the nanostructured explosives smoothly coated to the nanofibers of BC gelatin network at high RDX concentrations, and the granularity distributions of RDX in the nanostructured explosives were very uniform in the range of 30–50 nm. The average contents of the RDX in the nanostructured explosives are greater than 83 wt.% when the RDX concentrations of the soaked solutions are greater than 0.20 g/mL. The average content is approximately 91 wt.% when the RDX concentration is 0.30 g/mL. The decomposition temperatures of the RDX nanostructured explosives were found to decrease approximately to 20 C and their mechanical sensitivities decreased greatly compared to that of raw micro-size RDX. It opens a useful way to prepare nanostructured explosives with high energy and low mechanical sensitivity.

인화성액체의 폭발위험장소 설정을 위한 증발율 추정 모델 연구

정용재 ( Yong Jae Jung ),이창준 ( Chang Jun Lee ) 한국안전학회(구 한국산업안전학회) 2018 한국안전학회지 Vol.33 No.4

In many companies handling flammable liquids, explosion-proof electrical equipment have been installed according to the Korean Industrial Standards (KS C IEC 60079-10-1). In these standards, hazardous area for explosive gas atmospheres has to be classified by the evaluation of the evaporation rate of flammable liquid leakage. The evaporation rate is an important factor to determine the zones classification and hazardous area distance. However, there is no systematic method or rule for the estimation of evaporation rate in these standards and the first principle equations of a evaporation rate are very difficult. Thus, it is really hard for industrial workplaces to employ these equations. Thus, this problem can trigger inaccurate results for evaluating evaporation range. In this study, empirical models for estimating an evaporation rate of flammable liquid have been developed to tackle this problem. Throughout the sensitivity analysis of the first principle equations, it can be found that main factors for the evaporation rate are wind speed and temperature and empirical models have to be nonlinear. Polynomial regression is employed to build empirical models. Methanol, benzene, para-xylene and toluene are selected as case studies to verify the accuracy of empirical models.

Highly Energetic Materials-Hosted 3D Inverse Opal-like Porous Carbon: Stabilization/Desensitization of Explosives

Shin, Moo-Kwang,Kim, Myeong-Hoon,Kim, Ga-Yun,Kang, Byunghoon,Chae, Joo Seung,Haam, Seungjoo American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.50

<P>The precise control of sensitivity to external stimuli, for example, impact, friction, and thermal energy, has been emphasized for highly energetic materials, including RDX and HMX. Such sensitivities could be controlled by adjusting the surface area or (in)organic additives; however, increased stability leads to a decrease in the explosives’ performance. Here, high-energy-density molecules hosted in inverse opal-like porous carbon (IOC) nanocomposites demonstrate the mechanical stabilization and desensitization of RDX and HMX inside the carbon nanostructure using host-guest chemistry techniques. For this strategy, the uniform, vacant voids of the IOC were used to provide internal crystallization for the impact/frictional stabilization of explosives, and also to enhance the thermal reactivity by the high heat conductivity of IOC initiating detonation by thermally induced hotspot. The weight percentage of high explosives hosted by recrystallization at high temperatures and in vacuum reached ∼70%. After high explosives were embedded inside the IOC, the impact, friction and electrostatic stability was greatly increased (2-2.15-fold, 1.86-1.92-fold, and 1.25-2-fold, respectively) compared with free RDX and HMX. Also, addition of PVP as a binder controlled the effectiveness and efficiency of the carbon template, enabling control of the impact and friction sensitivity from 14.72 J to >79.43 J and from 295.81 to 352.80 N, respectively.</P> [FIG OMISSION]</BR>

다중벽 탄소나노튜브의 분진폭발 특성

한인수 ( In Soo Han ),이근원 ( Keun Won Lee ),최이락 ( Yi Rac Choi ) 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.1

가연성 분진이 제조·취급되는 공정에서의 분진폭발 위험성은 항상 존재한다. 그러나 산업현장에서 취급되는 분진에 대한 분진폭발 특성 정보는 아주 미흡한 실정으로 사업장에서는 화학사고 예방대책 수립에 어려움을 겪고 있다. 본 연구에서는 입도분포가 다른 두 종류의 다중벽 탄소나노튜브(MWCNT)에 대한 분진폭발 특성을 실험적으로 조사하였으며, NFPA 499 Code를 적용하여 MWCNT 제조·취급 공정의 분진폭발 위험장소 구분을 검토하였다. 그 결과 평균입도가124.2 μm인 MWCNT 1의 P_max, K_st, LEL, MIE, 및 MIT는 각각 6.3 bar, 56 bar·m/s, 125 g/m³, 1000 mJ 초과 및 650 ℃ 초과로 나타났다. 평균입도가 293.5 μm인 MWCNT 2의 P_max, K_st, LEL, MIE, MIT는 각각 6.2 bar, 42 bar·m/s, 100 g/m³, 1000 mJ 초과 및 650 ℃ 초과로 나타났다. NFPA 499 Code에 따른 MWCNT 1, 2의 폭발강도와 점화감도는 각각 0.35와 0.01 미만으로 나타났기 때문에 MWCNT는 NFPA 499 Code에서 제시된 분진폭발 위험장소로 구분하여야 하는 가연성 분진으로 분류되지 않았다. Dust explosion hazards are always present when combustible dusts are manufactured or handled in the process. However, industries is experiencing difficulty in establishing chemical accident prevention measures because of insufficiency of information on dust explosion characteristics of combustible dust handled in industry. In this study, we investigated experimentally dust explosion characteristics of two kinds of multi-walled carbon nano tubes (MWCNT) different in particle size distribution and examined classification of dust explosion hazardous area for MWCNT manufacturing or handling process by applying the NFPA 499 code. As a result, P_max, K_st, LEL, MIE and MIT of MWCNT 1 having 124.2 μm median diameter are obtained 6.3 bar, 56 bar·m/s, 125 g/m³, over 1000 mJ, and over 650 ℃. P_max, K_st, LEL, MIE and MIT of MWCNT 2 having 293.5 μm median diameter are 6.2 bar, 42 bar·m/s, 100 g/m³, over 1000 mJ, and over 650 ℃, respectively. MWCNT 1, 2 are not categorized as combustible dust listed in the NFPA 499 Code for classification of dust explosion hazardous area because explosion severity and ignition sensitivity of MWCNT 1, 2 are below 0.35 and 0.01, respectively.

미분체 반응성 위험물의 발화감도 및 폭발압력

한우섭,이근원 한국화재감식학회 2014 한국화재감식학회 학회지 Vol.5 No.2

The measurement of explosion hazard parameters using materials of serious explosion incidents has been examined experimentally such as maximum explosion pressure rise, thermal composition, ignition sensitivity of impact and friction. For this purpose, three different samples of benzoyl peroxide 97%, phthalic anhydride and 1- hydroxybenzotriazol were used and experimental investigations were conducted by using DSC, Pressure vessel tester, BAM fall hammer tester, BAM friction tester and 20L explosion chamber. As the results, from the results of DSC , the ignition temperature of BPO and 1-Hydroxybenzotriazol were observed at 107.07℃ and 209.14℃, respectively. And it was found that the heat sensitivity and explosion pressure of 1-Hydroxybenzotriazol was very high.

혼합 가스폭발이 지하구조물 안정성에 미치는 영향 평가

김민주 ( Minju Kim ),권상기 ( Sangki Kwon ) 대한화약발파공학회 2020 화약발파 Vol.38 No.4

국내의 지하공간 활용이 증가함에 따라 지하에 매설되어 있는 가스관과 같은 시설물에서의 폭발 사고가 꾸준히 발생하고 있다. 인구밀도가 높은 도심지에서는 개별의 폭발 사고가 복합적인 큰 사고로 확산될 가능성이 존재한다. 따라서, 도심지에서의 폭발이 지하구조물의 안정성에 미치는 영향을 평가하는 것이 필요하다. 본 연구에서는 터널과 인접한 곳에서의 폭발이 지하구조물의 안정성에 영향력을 미치는 요인들의 영향을 파악하기 위하여 폭발 조건과 암반의 물성을 포함한 8개 인자들에 대한 민감도 분석을 실시하였다. AUTODYN을 이용한 민감도 분석을 통해 각 인자들의 주영향과 교호작용효과를 분석하였다. 분석 결과, 폭발지점과 지하구조물 사이의 거리, 폭약량, 암석의 탄성계수가 터널 주변 응력성분에 큰 영향을 미치는 것으로 나타났다. With the increase of the utilization of underground space in Korea, explosion accidents at the underground facilities such as gas pipes have occurred frequently. In urban area with high population density, individual explosion accidents are likely to spread into large complex accidents. It is necessary to investigate the effect of explosion on the stability of underground structures in urban area. In this study, a sensitivity analysis was carried out to investigate the possible influence of nearby explosion on the stability of underground structure with 8 parameters including explosion conditions and rock properties. From the sensitivity analysis using AUTODYN, the main and interaction effects of each parameters could be determined. From the analysis, it was found that the distance between explosion point and tunnel, charge weight, and Young’s modulus are the most important parameters on the stress components around a tunnel.