• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.34 no.1
• /
• pp.1-8
• /
• 2021

Vapor cloud explosions show different characteristics from that caused by ordinary TNT explosives and their loading effect is similar to pressure waves. Typical methods used for blast pressure calculations are the TNT-equivalent method and multi-energy method. The TNT-equivalent method is based on shock waves, similar to a detonation phenomenon, and multi-energy method is based on pressure waves, similar to a deflagration phenomenon. This study was conducted to derive an appropriate blast pressure by applying various plant explosion cases. SDOF analysis and nonlinear dynamic analysis were performed to compare the degree of deformation and damage of the selected structural members for the explosion cases. The results indicated that the multi-energy method was more exact than the TNT-equivalent method in predicting the blast pressure of vapor cloud explosions. The blast pressure of vapor cloud explosion in plants can be more accurately calculated by assuming the charge strength of multi-energy method as 7 or 8.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.30 no.4
• /
• pp.117-131
• /
• 2022

Human rights education is to acquire understanding and knowledge about human rights, to develop values, attitudes and character that respect human rights, to develop the ability to overcome human rights violations and discriminatory acts, and to protect and promote the human rights of others. In order to prevent human rights violations of the transportation vulnerable, such as the disabled, it is necessary to develop specialized human rights education plans for aviation security personnel to practice human rights perspectives. Therefore, in accordance with the 「National Civil Aviation Security Education and Training Guidelines」, specialized human rights education should be included in the initial aviation security education and regular education courses. The point is that there is a need to reexamine the aviation security education program for aviation security personnel based on the essential knowledge and educational contents for aviation security personnel to perform security screening tasks in the aviation security education course. When this happens, various efforts must be made to improve the human rights of the transportation vulnerable, such as the disabled, during the security screening process, so that human rights violations will be significantly reduced. In particular, it is necessary to enhance the ability to detect dangerous terrorist items such as weapons or explosives that can be used for illegal sabotage through practical security screening training. For aviation security and aircraft safety, efforts to improve the quality of aviation security personnel training, such as human rights training, must be continuously made while thoroughly preparing for terrorism in advance.

• Journal of Korean Society of Disaster and Security
• /
• v.16 no.1
• /
• pp.91-103
• /
• 2023

This study aims to investigate the dynamic fracture characteristics of rocks and rock-like materials subjected to the Nonex Rock Cracker (NRC), a vapor pressure crushing agent that produces vapor pressure by instantaneously vaporizing a liquid mixture crystallized through the thermite reaction. Furthermore, the study seeks to develop an analytical technique for predicting the fracture pattern. A dynamic fracture test was performed on a PMMA block, an artificial brittle material, using the NRC. High-speed cameras and dynamic pressure gauges were employed to capture the moment of vapor pressure generation and measure the vapor pressure-time history, respectively. The 2-dimensional Dynamic Fracture Process Analysis (2D DFPA) was used to simulate the fracture process caused by the vapor pressure, with the applied pressure determined based on the vapor pressure-time history. The proposed analytical method was used to examine various fracture patterns with respect to granite material and high-performance explosives.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.33 no.4
• /
• pp.609-619
• /
• 2023

Recently, crimes using drones, one of the IoT industries have been continuously reported. In particular, drones are characterized by easy access and free movement, so they are used for various crimes such as transporting explosives, transporting drugs, and illegal recording. In order to analyze and investigate these criminal acts, drone forensic research is highly emphasized. Media data, PII, and flight records are digital forensic artifacts that can be acquired from drones, in particluar flight records are important artifacts since they can be used to trace drone activities. Therefore, in this paper, the characteristics of the deleted flight record files of DJI drones are presented and verified using the Phantom3, Phantom4 andMini2 models, two drones with differences in characteristics. Additionally, the recovery level is analyzed using the flight record file characteristics, and lastly, drones with the capacity to recover flight records for each drone model and drone models without it are classified.

• Clean Technology
• /
• v.15 no.4
• /
• pp.233-238
• /
• 2009

Supercritical fluid processes have gained great attention as a new and environmentally-benign method of preparing the microparticles of energetic materials like explosives and propellants. In this work, RDX (cyclotrimethylenetrinitramine) was selected as a target explosive. The microparticle formation of RDX using supercritical anti-solvent (SAS) recrystallization process was performed and the effect of operating variables on the size and morphology of prepared particles was observed. N,N-Dimethylformamide was used as organic solvent for dissolving the RDX. The size of the RDX particles decreased remarkably up to less than $10\;{\mu}m$ by SAS recrystallization. In the range of operating conditions of the SAS process studied in this work, the finest RDX particles were obtained at 313.15K, 150 bar, and 15wt% RDX concentration in feed solution.

• Analytical Science and Technology
• /
• v.21 no.2
• /
• pp.129-134
• /
• 2008

Cyclic voltammetry (CV) and square wave stripping voltammetry (SW) analysis of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) using the double-stranded ds calf thymus (DNA) mixed in carbon nanotube paste electrode (PE) were provided. The optimum analytical conditions were determined and the peak potential was 0.2 V vs. Ag/AgCl. The linear working ranges of CV (50-75 ug/L) and SW (5-80 ng/L) were obtained. The precisions of RSD in the 10 ug/L was 0.086% (n=15) and the detection limit was 0.65 ng/L ($2.92{\times}10^{-12}M$) (S/N=3) with 300 s adsorption time at the optimum condition. The method was used to determine the presence of explosive chemicals in contaminated soil samples.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.5
• /
• pp.403-407
• /
• 2023

This study started with the background that future South Korean military organizations should develop a complex system linking unmanned systems by analyzing and considering cases using "drone," which has recently become an essential means of war. In 2014 and 2022, South Korea is facing serious security threats from North Korean drones that have recently invaded South Korea's airspace in a row. If a North Korean drone was loaded with explosives and poisonous gas and invaded our airspace, the damage would be more serious. Furthermore, what the Azerbaijan-Armenian War of 2020 and the ongoing Ukraine-Russia war have in common is that battles using "combat drones" are underway. Watching this shift in the domestic and overseas war paradigm, drones have become essential for military operations. In the context of a "ceasefire" and the military environment on the Korean Peninsula, South Korea should actively develop "Combat drones" that take into account precise strikes and portability against targets linked to military drones.

• Advances in Computational Design
• /
• v.8 no.4
• /
• pp.309-325
• /
• 2023

An innovative inertial reactive armor is being developed through a multi-discipline project. Unlike the well-known explosive or non-explosive reactive armour that uses high-energy explosives or bulging effect, the proposed inertial reactive armour uses active disc elements that is set to rotate rapidly upon impact to effectively deflect and disrupt shaped charges and kinetic energy penetrators. The effectiveness of the proposed armour highly depends on the tangential velocity of the impact point on the rotating disc. However,for a single layer armour with an array of high-speed rotating discs, the tangential velocity is relatively low near the center of the disc and is not available between the gap of the discs. Therefore, it is necessary to configure the armor with double layers to increase the tangential velocity at the point of impact. This paper explores a multi-objective geometry design optimization for the double-layered armor using Nelder-Mead optimization algorithm and integration tools of the python programming language. The optimization objectives include maximizing both average tangential velocity and high tangential velocity areas and minimizing low tangential velocity area. The design parameters include the relative position (translation and rotation) of the disc element between two armor layers. The optimized design results in a significant increase of the average tangential velocity (38%), increase of the high tangential velocity area (71.3%), and decrease of the low tangential velocity area (86.2%) as comparing to the single layer armor.

• Composites Research
• /
• v.37 no.1
• /
• pp.21-31
• /
• 2024

This review paper investigates the use of shockwave attenuating materials within composite structures to enhance personnel protection against blast-induced traumatic brain injury (bTBI). This paper also introduces experimental methodologies exploited in the generation and measurement of shockwaves to evaluate the performance of the shock dissipating composites. The generation of shockwaves is elucidated through diverse approaches such as high-energy explosives, shock tubes, lasers, and laser-flyer techniques. Evaluation of shockwave propagation and attenuation involves the utilization of cutting-edge techniques, including piezoelectric, interferometer, electromagnetic induction, and streak camera methods. This paper investigates phase-separated materials, including polyurea and ionic liquids, and provides insight into composite structures in the quest for shockwave pressure attenuation. By synthesizing and analyzing the findings from these experimental approaches, this review aims to contribute valuable insights to the advancement of protective measures against blast-induced traumatic brain injuries.

• Nuclear Engineering and Technology
• /
• v.55 no.11
• /
• pp.4287-4294
• /
• 2023

In order to meet the energy demand, energy production must be done continuously. Hydrogen seems to be the best alternative for this energy production, because it is both an environmentally friendly and renewable energy source. In this study, the hydrogen fuel production of the peaceful nuclear explosives (PACER) fusion blanket as the energy source integrated with Fe-Cl thermochemical water splitting cycle have been investigated. Firstly, neutronic analyzes of the PACER fusion blanket were performed. Necessary neutronic studies were performed in the Monte Carlo calculation method. Molten salt fuel has been considered mole-fractions of heavy metal salt (ThF₄, UF₄ and ThF₄+UF₄) by 2, 6 and 12 mol. % with Flibe as the main constituent. Secondly, potential of the hydrogen fuel production as a result of the neutronic evaluations of the PACER fusion blanket integrated with Fe-Cl thermochemical cycle have been performed. In these calculations, tritium breeding (TBR), energy multiplication factor (M), thermal power ratio (1 - 𝜓), total thermal power (P_hpf) and mass flow rate of hydrogen (ṁ_H2) have been computed. As a results, the amount of the hydrogen production (ṁ_H2) have been obtained in the range of 232.24x10⁶ kg/year and 345.79 x10⁶ kg/year for the all mole-fractions of heavy metal salts using in the blanket.