As the most important component for MEMS-based pyrotechnics, the micrometer should generate enough energy to successfully ignite the next explosive. An enhanced reactive igniter was designed and fabricated through sputtering the Al/CuO nanolaminates onto the NiCr micro-heater to enhance the output energy of the NiCr micro-heater. The average thickness of the Al/CuO nanolaminate is 6.84 [Formula: see text]m, and the designed thickness is 6 [Formula: see text]m. The grain sizes of Al/CuO nanolaminates are not uniform, and the particle grains of the Al/CuO nanolaminates at the top are smaller than those at the bottom. When the applied currents passed through the igniter, the resistance of the igniter changed dynamically, leading to the igniter experiencing three stages. Compared to the bare NiCr micro-heater without depositing Al/CuO nanolaminates, the enhanced reactive igniter can successfully ignite Zr/KClO4 explosive, indicating that the Al/CuO nanolaminates could enhance the output capability of the NiCr micro-heater. It is of vital importance to guide the design of MEMS-based pyrotechnics.
BACKGROUND Iranian people celebrate the last Wednesday of the year also known as Chahar Shambeh Soori (CSS) using low explosive pyrotechnics classified as fireworks. Mishaps and accidents are common and maxillofacial fractures may occur which have a negative impact on the quality of life. This study aimed to assess maxillofacial fractures (fx) caused by explosive agents. METHODS This cross-sectional descriptive study assessed 283 patients suffering maxillofacial fxs caused by explosive agents during CSS ceremonies between 2009 and 2019 referred to our craniomaxillofacial (CMF) surgery center. The data assessed included age, sex, cause, type, site, and severity of injury, fracture patterns, treatment modalities, and complications. All maxillofacial injuries were evaluated and treated by Craniomaxillofacial staff surgeons. RESULTS Among 283 patients, 72.8% (206) and 27.2% (77) were men and women, respectively. The mean age of patients was 17.35 years. The most common maxillofacial fracture was in the mid-face; with the distribution of fractures being: 39.9% zygomatic fractures, 32.1% nasal bone fractures, 63.2% dentoalveolar fracture, 43.1% Le Fort (Le Fort I, Le Fort II, Le Fort III), 31.4% orbital, and 43.1% mandible fractures. The most frequent type of treatment was Open Reduction and Internal Fixation (ORIF) (77.4%). CONCLUSION The most common site of maxillofacial fractures and most frequent treatment used were similar to military or ballistic injuries. ORIF was common treatment.
Pyrotechnic agent was a sensitive energetic material that produces explosion and combustion effects of pyrotechnics. It plays a decisive role in the safety, reliability and effectiveness of the weapon system. Because the current pyrotechnic agent is sensitive to high temperature, mechanical impact, and friction, there are many unsafe factors in its manufacture and use. The demand of continuous, automatic and environmental protection production technology for pyrotechnics in China is increasing. The traditional sensitive explosive can not meet these requirements, so it is necessary to accelerate the development of sensitive explosive to safeandinsensitive explosive.Therefore, in order to solve the key issues such as the safety and high-efficiency preparation of multi-component pyrotechnic agents, realize the environmental protection, safety and low-cost production of pyrotechnic agents. Based on the project design of a mixed propellant production system in an initiating explosive device factory, this research carried out the research on the safety automatic particle forming equipment for initiating explosive. It provides technical support for the innovation of weapons and equipment, and the upgrading of weapons and equipment manufacturing and production technology.
Abstract The self-sustaining combustion of energetic materials, especially for propellants and pyrotechnics, is highly expected because it is related to various issues, such as combustion efficiency, ignition energy, and environmental protection. In this work, we present a method to solve the discontinuous and quenching combustion issues of energetic coordination polymer (ECP) by introducing graphene oxide (GO) into the growth of ECP. An ECP [(NiC2H4N8O4)n, Ni-BTO] constructed from Ni2+ and H2BTO [1H,1′H-(5,5′-bitetrazole)-1,1′-bis(olate)] ligand is in situ grown on GO layers. The abundant active sites of GO derived from its oxygen groups make it participate in the coordination and polymerization of Ni-BTO, thereby inducing a new kind of ECP (GO-Ni-BTO). The induction effect of GO reduces the size of Ni-BTO particles to the nanoscale and allows them to chemically bond to GO layers. The effects of different GO contents on the exothermic, combustion, and pressure-generation properties of GO-Ni-BTO are systematically investigated. Results indicate that GO-Ni-BTO ECP with 7.5 wt% GO content can solve the quenching and discontinuous combustion issues presented by micro-size Ni-BTO with a higher heat output (3265.58 J·g-1) because of the reduced size of GO-Ni-BTO, oxygen-release ability of GO, and strong thermal conductivity of reduced GO. Correspondingly, the peak pressure and pressurization rate of GO-Ni-BTO ECP with 7.5 wt% GO content are also greatly enhanced. This interesting GO-Ni-BTO ECP can be used as a heat source for the initiation of secondary explosives and as a gas generator for the propulsion system.
Gas-explosion events in the private or industrial field are usually followed by a technical analysis of the factors that led to their generation. In this respect, INCD INSEMEX Petroşani is accredited for conducting the technical expertise and for the elaboration of the Expertise Report. Starting with on-site findings and sampling, research continues at INCD INSEMEX laboratories, grouped on areas of interest in case management (electrical, ventilation, chemical, pyrotechnics, etc.). Determining the causes of the event implicitly involves establishing the probable source of initiation of the explosive mixture, after discovering the fuel gas source and analyzing how the mixture was formed. Due to the geometric complexity of the space in which the explosion occurred, incident, reflected or compound shock waves generated by explosion can create a footprint of the event that questions the location of the source of initiation. Depending on the possible sources found in the field, the INSEMEX Laboratory of Computational Simulations performs analyzes based on finite elements and finite volumes methods. The elements taken into account in the computational simulations concern both the geometry of the space, the nature of the combustible gas leakage, the dispersion of the gas, and the resulting thermal and mechanical effects.
Abstract Mild detonating fuse (MDF) plays a vital role in pyrotechnics separate devices. Energy output efficiency of MDF has significances to the structural design of pyrotechnics devices. A deformation cylinder tube testing set for small counts of explosive charge was developed to estimate energy output efficiency of MDF. Charge density and detonation velocity of MDF were measured experimentally. Detonation heat of MDF charge was calculated based on Kamlet equations and experimental results. Three kinds of copper tubes with uniform inner diameter and different outer diameters were used in the tests, which were loaded by the same MDF. Plastic strain energy of the copper tube was calculated by measuring the recycled tube. The results show that the range of energy output efficiency of MDF is 57.6%–60.0%. Furthermore, the experiments were simulated by dynamic finite element software LS-DYNA, and simulated deformation results of copper tube were consistent with experimental results. According to the simulated results, the plastic strain energy of copper tube and energy transform efficiency were investigated in detail. The results show that energy output efficiency of MDF is reduced with the increase of outer diameter of the copper tube, and nearly keeps unchangeable when enough elastic zone occurs in the tube.