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This research work emphasizes on the development aspects of a cartridge cable cutter for helicopter application. This cartridge is used to rescue hoist system during emergency for helicopter application under adverse conditions. It is an electrically initiated cartridge in which two electrical squibs are used with specified current and voltage. As the cartridge is initiated, the squib gets incandescent and initiates an explosive train. A cartridge cable cutter is a propellant actuated device (PAD) that generates hot combustion gases having high temperature and pressure on burning of gun powder and propellant inside the cartridge case. The cable cutter cartridge under study is filled with energetic materials (EM) such as propellants and gun powder. It releases the energy very quickly which acts on the projectile i.e. the cutter in actual system. A projectile velocity measurement was carried out using Doppler RADAR (radio detection and ranging). To assess the projectile velocity is the unique design feature in armament field. It is responsible for the measurement of the projectile velocity at the muzzle end of velocity test rig (VTR). The minimum and maximum projectile velocities were experimentally measured in between 70 ms−1 and 150 ms−1. The projectile velocity measurement is an evaluation methodology as performance parameter of this cartridge. The cartridge under study has been developed meeting structural, functional and mechanical requirements. The cartridge has undergone various exhaustive qualification tests during development phase. The cartridge was thus designed, qualified and validated through rigorous development trials. The main objective of this article is to address development aspects of the cartridge cable cutter for helicopter application. In conclusion, after successful design, development and qualification trials, the cartridge was found to meet all the functional and operational requirements considering the end use. [ABSTRACT FROM AUTHOR]

Point cloud data obtained from scanning propellant grains with 3D scanning equipment exhibit positional uncertainty in space, posing significant challenges for calculating the relevant parameters of the propellant grains. Therefore, it is essential to normalize the position of each propellant grain's point cloud. This paper proposes a normalization algorithm for propellant grain point clouds, consisting of two stages, coarse normalization and fine normalization, to achieve high-precision transformations of the point clouds. In the coarse normalization stage, a layer-by-layer feature points detection scheme based on k-dimensional trees (KD-tree) and k-means clustering (k-means) is designed to extract feature points from the propellant grain point cloud. In the fine normalization stage, a rotation angle compensation scheme is proposed to align the fitted symmetry axis of the propellant grain point cloud with the coordinate axes. Finally, comparative experiments with iterative closest point (ICP) and random sample consensus (RANSAC) validate the efficiency of the proposed normalization algorithm. [ABSTRACT FROM AUTHOR]

Combustible cartridge cases are parts of modular charges used in modern artillery systems. Some types of combustible cartridge case materials have exhibited problems during pyrostatic measurements caused by their difficult ignition. This article explores the possibility of testing the combustible cartridge case material mixed with a propellant of known ballistic properties and then separating the influence of that propellant using methods of mathematical analysis. The aim of this work is to create methodology for closed vessel tests of combustible cartridge case material. Outcome involves the characterization of combustible cartridge case material ballistic properties, including its burn rate parameters. Calculations described in this paper could potentially be modified to be applicable to other cases of mixture of two propellants. [ABSTRACT FROM AUTHOR]

The purposes of this study were to evaluate the bulk sample concentration and airborne concentrations of phthalate in different types of propellent and triggers in consumer spray products and estimate health risk assessment via inhalation. First, the phthalate concentrations were analyzed in the solutions of all products 174 from markets. Then, among 64 products containing phthalates, 10 propellant-type products were selected that contained high phthalate concentrations; airborne concentrations were measured at distances of 1, 3, and 5 m from the spray nozzle in a clean room. Four phthalates were detected in spray products: diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), butyl benzyl phthalate (BBzP), and bis(2-ethylhexyl) phthalate (DEHP). Among propellant-type products, repellents contained the highest mean concentrations (3.90 ppm), whereas sterilized products contained the lowest mean concentrations (0.59 ppm). Among trigger-type products, cleaning products contained the highest mean concentrations (4.54 ppm), whereas coating products contained the lowest mean concentrations (0.73 ppm). In both propellant- and trigger-type products, DnBP and DEHP exceeded the standard set by the Ministry of Food and Drug Safety of South Korea. No significant patterns were observed for the airborne DiBP, DnBP, and DEHP concentrations at 1, 3, and 5 m (p > 0.05). Children were one of the population groups most susceptible to health risks. Overall, phthalates were detected in both product solutions and the air in consumer spray products; some even exceeded safe limits. Therefore, consumer spray products should be used in well-ventilated areas to avoid respiratory exposure. [ABSTRACT FROM AUTHOR]

Both glycidyl azide polymer (GAP) and hexanitrohexaazaisowurtzitane (CL-20) are high-energy compounds with very promising applications. However, there are relatively few relevant studies for GAP/CL-20 aluminum-based propellants. In this paper, the CCPs of aluminum-based GAP/CL-20 propellant under different operating conditions were collected by a gas collecting device, and the physicochemical properties of CCPs were carefully studied by various modern analytical and testing instruments. The results show that the CCPs consist mainly of smoke oxide particles (~1 μm), residual oxide particles (~20 μm) and agglomerates. Residual oxide particles are widely available, but have received less attention from researchers. The agglomerates can be divided into two categories: sphere-like agglomerates and non-spherical agglomerates. Sphere-like agglomerates include cracked spheres, solid spheres, hollow spheres, and spheres with oxide caps. Surprisingly, we found an agglomerate with two caps. Non-spherical agglomerates are larger in size than sphere-like agglomerates, and the non-spherical agglomerates include irregular agglomerates, coral-like aggregates, and filamentous agglomerates. As far as we know, coral-like aggregates and filamentous agglomerates in CCPs have not been reported in the literature. Pocket theory and inter-pocket bridge theory were used to explain the formation mechanism of fine filament agglomerates. In addition, the formation mechanisms of different types of agglomerates were analyzed and sorted out. The particle size distribution of CCPs at different pressures shows that the average particle size of CCPs decreases with increasing pressure. It is hoped that this paper can provide a reference for the design of high-energy propellant formulations. [ABSTRACT FROM AUTHOR]

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article reports two accidents caused by defective Takata airbags ruptured, which led to the deaths of the drivers. This is the first public report on the deaths caused by Takata airbags in China. Determine the relationship between the driver death and airbag rupture through autopsy indings and vehicle inspection. Due to defects in the design of Takata's inflator, moist air was permitted to slowly enter the inflator, resulting the PSAN slowly degraded physically. The damaged propellant burned more rapidly than intended and overpressurized the inflator's steel housing, causing fragmentation and flying debris at high speed, killing or injuring vehicle occupants. To date, there are still tens of millions of defective Takata airbags that have not been recalled for repair, posing safety risks. This article suggests taking preventive measures to avoid the occurrence of similar accidents. [ABSTRACT FROM AUTHOR]

This study demonstrates, for the first time ever, the ability to grow, in an on‐command fashion, porosity within a granular composite energetic material to effect a change in energy output rate. Specifically, the study investigates the change in burning rates of ammonium perchlorate composite propellants as a result of porosity created in situ via microwave field‐driven volatilization of the low boiling point binder additive, ethylene glycol. Theoretical mass densities were measured before and after microwave irradiation finding that the maximum observed %TMD change for tested propellants is 6 %. Propellants were burned at 1.72 MPa to 6.89 MPa pressures, finding that for all propellants, microwave irradiation produced a change in ballistic characteristics. Most propellant formulations demonstrate acceptable burning rate parameters for use within rocket motors; some exhibited a large change in their pressure exponent as well as slope breaks attributed to the onset of convective burning, while microwave irradiation produced no change in burning rate or density in reference propellants without the additive. Microwave heating simulation results are presented to gain insight into the thermal environment of the propellant during microwave irradiation. These results provide valuable insight into propellant formulations that can have their burning rates (and thus the thrust profile for motor grains) altered after casting via microwave irradiation. [ABSTRACT FROM AUTHOR]

This study focuses on an innovative green propellant based on paraffin, stearic acid, and coal, used in hybrid rocket engines. Additionally, lab-scale firing tests were conducted using a hybrid rocket motor with gaseous oxygen as the oxidizer, utilizing paraffin-based fuels containing stearic acid and coal. The mechanical performance results revealed that the addition of stearic acid and coal improved the mechanical properties of paraffin-based fuel, including tensile, compression, and flexural strength, under both ambient and sub-zero temperatures (−21 °C). Macrostructural and microstructural examinations, conducted through optical and scanning electron microscopy (SEM), highlighted its resilience, despite minimal imperfections such as impurities and micro-voids. These characteristics could be attributed to factors such as raw material composition and the manufacturing process. Following the mechanical tests, the second stage involved conducting a firing test on a hybrid rocket motor using the new propellant and gaseous oxygen. A numerical simulation was carried out using ProPEP software to identify the optimal oxidant-to-fuel ratio for the maximum specific impulse. Following simulations, it was observed that the specific impulse for the paraffin and for the new propellant differs very little at each oxidant-to-fuel (O/F) ratio. It is noticeable that the maximum specific impulse is achieved for both propellants around the O/F value of 2.2. It was observed that no hazardous substances were present, unlike in traditional solid propellants based on ammonium perchlorate or aluminum. Consequently, there are no traces of chlorine, ammonia, or aluminum-based compounds after combustion. The resulting components for the simulated motor include H2, H2O, O2, CO2, CO, and other combinations in insignificant percentages. It is worth noting that the CO concentration decreases with an increase in the O/F ratio for both propellants, and the differences between concentrations are negligible. Additionally, the CO2 concentration peaks at an O/F ratio of around 4.7. The test proceeded under normal conditions, without compromising the integrity of the test stand and the motor. These findings position the developed propellant as a promising candidate for applications in low-temperature hybrid rocket technology and pave the way for future advancements. [ABSTRACT FROM AUTHOR]

Stabilisers are an integral part of a propellant composition. They are essential for ensuring the chemical stability of nitrate‐ester based propellants, preventing oxidation, chain scission and uncontrolled heat generation. Progress is being made, especially in Europe, with REACh legislation (1907/2006) to use more environmentally‐friendly compounds. New stabilisers with a greener environmental profile and producing less toxic daughter products have been investigated by several groups, and several compounds demonstrated even better performances – more chemical stability and therefore longer shelf lives than formulations with the currently‐used stabilisers. Additionally, the good efficiencies and lower toxicities of the daughter products of the "green" stabilisers are also evaluated. This paper is a continuation of our previous work and demonstrates that for industrially‐manufactured propellants, that the tests performed by four different entities validate the stability and compatibility of the propellants, investigated previously on a laboratory scale, providing the community with safer formulations for the environment and health. [ABSTRACT FROM AUTHOR]

The advent of space exploration missions, especially those aimed at establishing a sustainable presence on the Moon and beyond, necessitates the development of efficient propulsion and mission planning techniques. This study presents a comprehensive analysis of chemical and electric propulsion systems for spacecraft, focusing on optimizing propellant distribution for missions involving transfers from Low-Earth Orbit (LEO) to Geostationary Orbit (GEO) and the Lunar surface. Using mathematical modeling and optimization algorithms, we calculate the delta-v requirements for key mission segments and determine the propellant mass required for each propulsion method. The results highlight the trade-offs between the high thrust of chemical propulsion and the high specific impulse of electric propulsion. An optimization model is developed to minimize the total propellant mass, considering a hybrid approach that leverages the advantages of both propulsion types. This research contributes to the field of aerospace engineering by providing insights into propulsion system selection and mission planning for future exploration missions to the Moon, Mars, and Venus. [ABSTRACT FROM AUTHOR]

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, the precursors of composite aerogels were synthesized based on the homogeneous reaction of natural polymers with ionic liquids. Nitrochitosan (NCS) with nitrogen content of 15.99% and impact sensitivity of 12 J was synthesized under mild conditions, while nitrocellulose (NC) with nitrogen content of 12.52% was synthesized. The NC/NCS composite aerogel was prepared by using phase separation method and supercritical carbon dioxide drying system. The structure and morphology of the samples were characterized by FTIR, XRD, Raman, SEM, element mapping, and N2 adsorption and desorption. The thermal and burning behavior of precursors and composite aerogels were analyzed by TG-DSC, isothermal TG, TG-DSC-FTIR, and high-speed camera. The results show that NCS can be used as propellants in terms of thermal behavior and physicochemical property. The composite aerogel has uniform distribution of nitrogen elements, mesoporous structure with an average pore size of 20 nm, specific surface area greater than 100 m2/g, large heat of thermal decomposition, low activation energy, well thermal stability, stable burning behavior, and large size burning flame. NC/NCS composite aerogels have a great potential for use in high-speed micro-propulsion system. [ABSTRACT FROM AUTHOR]

A series of aziridino[60]fullerenes was synthesized by the reaction of octabromo[60]fullerene with various anilines. Their ability to absorb free radicals and acid gases was studied, and their potential applications as stabilizers in nitrocellulose-containing propellants were discussed. The results of differential thermal analysis showed that aziridino[60]fullerene can increase the exothermic peak temperatures of nitrocellulose by 0.55–2.37 °C. The methyl violet test found that aziridino[60]fullerenes can extend the complete decomposition period by 31–71 min. The results of vacuum stability test and thermogravimetric test indicated that aziridino[60]fullerene can delay the decomposition of nitrocellulose. Furthermore, their stabilization mechanism was studied by electron spin resonance spectroscopy, and the free-radical scavenging rate of 3c reached 86.09%. The findings demonstrate that aziridino[60]fullerenes could effectively eliminate the nitrogen oxides released by nitrocellulose autocatalysis and might be used as a new stabilizer for nitrocellulose-containing propellants. [ABSTRACT FROM AUTHOR]

Seven formulations of ammonium perchlorate composite propellant (APCP) are developed and their properties relevant for successful additive manufacture are characterized. Extrusion in a custom‐built 3D printing system and spindle viscometry are used to collect viscosity measurements of curing primary and non‐curing secondary versions of the formulations. The formulations that behave similarly to a Bingham plastic, with apparent viscosities between 4 and 8 thousand Pa*s at 30 minutes post‐mix, are determined to be most suitable for printing applications. Measurements of one material show a yield stress of 1 kPa. Ambient pressure burn rates of 2.0–2.9 mm/s were measured for the compositions tested. All measured burn rates were comparable to the lower end of typical burn rates for APCP. The results of the characterization demonstrate a propellant suitable for use in a 3D printing system. [ABSTRACT FROM AUTHOR]

Aluminum is widely used in solid rocket propellants to improve the energy performance of the propellant. However, during propellant combustion, aluminum particles may agglomerate, resulting in slag deposition, incomplete combustion of metal particles, increased two‐phase flow losses, and reduced motor specific impulse. Therefore, it is of great scientific significance and engineering value to understand the agglomeration mechanism of aluminum particles and to explore the method of agglomeration suppression. Based on this, this paper firstly briefly introduced the agglomeration process of aluminum particles during propellant combustion. Subsequently, factors influencing the agglomeration of aluminium particles were analysed. The influencing factors can be roughly divided into two aspects: propellant's own formulation and external environment. Immediately afterwards, the existing agglomeration suppression methods were emphasized and summarized and analyzed. Presently, agglomeration suppression methods can be broadly classified into four categories, namely, conventional formulation optimization, use of aluminum nanoparticles, and modification of aluminum particles using fluorine‐containing compounds or alloy particles. Finally, several directions that need to be focused on in the future are proposed to address the problems in the study of aluminum particle agglomeration suppression methods. [ABSTRACT FROM AUTHOR]

The process of solid propellant production, which is the most widely used high-energy material, has garnered significant attention from researchers. However, there have been relatively few studies on its processing, due to the unique nature of the casting process. This paper aims to further analyze the pouring process of the propellant slurry. Initially, we obtained a sample of the propellant slurry and measured its rheological parameters using a rotary rheometer. From the analysis of the experimental results, we derived the viscosity parameters and the yield values of the propellant slurry. Subsequently, we simulated the pouring process, setting the slurry parameters based on the data obtained from the rheological measurement experiment. The simulation results demonstrated that the flower plate significantly impacts upon the cutting and separating effect on the slurry during pouring. Upon leaving the flower plate, the slurry descends onto the core mold platform under the influence of gravity, gradually flowing along the edge of the core mold. Although there may be some small voids in the pouring process, the voids will disappear completely at the end of pouring. A comparison with the actual pouring situation revealed a higher consistency between the simulation results and reality, thus establishing the reliability of the simulation method as a reference for analyzing the pouring process. [ABSTRACT FROM AUTHOR]

Polydopamine (PDA) has been widely used in the field of energetic materials; however, there are few reports on the ammonium perchlorate (AP) coating of PDA. In this article, to improve the mechanical properties of the GAP‐ETPE‐based propellant, a two‐step method was used to coat the AP with PDA and used in glycidyl azide polymer (GAP) based propellant. SEM, EDS, XRD, and XPS were used to analyze the morphology and composition of PDA@AP, while contact angle testing and calculation were performed to measure the wettability and surface energy of both PDA@AP and GAP‐ETPE. In addition, the tensile strength and elongation of the propellant were measured. The results showed that the PDA@AP composite particles were successfully prepared. The crystal form remained unchanged during the preparation process. The wettability of PDA on AP was improved through the coating of PDA, leading to an increase in the surface energy of AP and enhancing the adhesion between AP and GAP. Mechanical performance testing shows that using PDA@AP in propellants increased the tensile strength of the propellant from 1.2 to 1.8 MPa, while the elongation at break decreased from 208% to 155%. The "dewetting ratio" has also decreased from 2.88 to below 2.5. [ABSTRACT FROM AUTHOR]

The current paper presents the architecture of a test bench for small (laboratory) scale hybrid rocket motors destined for teaching purposes. The sustainability of the proposed methodology is emphasized, as it addresses the development of small-scale hybrid rocket motor test benches, to be used either as didactic means for students or for research laboratories, by using low-cost materials, while preserving efficiency. In this regard, the entire development process is approached, from designing to manufacturing (including the casting of the fuel rod) and testing of the product. The developed product uses a mixture of 88 % paraffin, 10% stearic acid, and 2% coal for the solid phase and liquid oxygen for the liquid phase. The testing of the hybrid rocket motor demonstrator was performed outdoors, in controlled conditions. The results showed a good correlation between the theoretical testing parameters with the obtained ones. [ABSTRACT FROM AUTHOR]

HFC-134 is the main impurity of HFA-134a. In order to verify the rationality of HFC-134 limits in HFA-134a and ensure the safety of HFA-134a as propellant in pharmaceutical metered-dose inhalers, acute inhalation toxicity, seven-day repeat dose inhalation irritation study, 21-day repeat dose inhalation toxicity study and reverse mutation assay of HFC-134 were tested to evaluate its inhalation safety. In acute inhalation studies, Sprague-Dawley rats were exposed nose-only to HFC-134 at levels of 100 000, 200 000, 400 000, 600 000, and 800 000 ppm for 4 h. Based on the mortality incidence, the calculated four-hour LC50 value for HFC-134 is 532 069 ppm for males and 502 058 ppm for females and acute inhalation toxicity is manifested as the lung lobes turn dark red. Exposures to 836 ± 67 ppm for 4 hours/day 7 days/week continuously did not induce local irritation of the respiratory system in Sprague-Dawley rats. Sprague-Dawley rats were exposed nose-only to HFC-134 at levels of 0 (control), 203 929 ppm and 394 871 ppm 2 h/day for 21 consecutive days, no significant treatment-related adverse effects was noted. Results from Ames studies demonstrated that HFC-134 was not mutagenic. Although HFC-134 has a very low acute inhalation toxicity, considering that its acute inhalation toxicity is higher than that of HFA-134a, and due to the high frequency of use of MDI by asthma patients, acceptance criteria of HFC-134 as the impurity in aerosol propellant HFA-134a should be lower than 8-h TWA WEEL value of 1000 ppm to ensure the safety of the MDI. [ABSTRACT FROM AUTHOR]

The thermal decomposition of an ammonium dinitramide-based energetic compound was conducted for the first time using a dispersive inductively coupled plasma mass spectrometer, DTA-TG analysis, and pyrolysis at a constant temperature. A liquid droplet was injected over synthesized CuO catalytic particles deposited on lanthanum oxide-doped alumina. The thermal behavior of the ADN liquid monopropellant revealed that decomposition in the presence of catalytic particles occurs in two distinct steps, with the majority of ejected gases being detected in real-time analysis using the DIP-MS technique. At a temperature of 280 °C, pyrolysis confirmed the catalytic decomposition behavior of ADN, which occurred in two distinct steps. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nitroglycerin (NG) is a high explosive that is difficult to handle in its liquid form, where the entrapment of gaseous NG bubbles results in its high sensitivity to impact (<0.25 J). NG‐based materials are traditionally prepared by complex mixing processes where desensitisation is of major concern. Instead of using a mixing procedure here we demonstrate the successful synthesis of dynamite‐like materials by using a single step bottom‐up approach to form a polymeric host matrix (PM) for NG from a solution which contains the explosive and the matrix precursors. For this purpose, an epoxidized vegetable oil mixed with nitroglycerin (oil to NG mass ratio of 60/40) is polymerized at 100 °C for 30 h by using glutaric acid as crosslinking agent. No degradation of NG under these conditions is observed. The activation energy of NG desorption from the PM (51.9 kJ/mol) is of the same order of magnitude as the one reported in literature for a double‐base powder (81.9 kJ/mol). An accelerated NG desorption is observed as temperature increases. This can be attributed to a slow diffusion mechanism of the explosive from the volume to the surface of the material, where it evaporates. The ignition of NG/PM in air by an open flame leads to a self‐sustained combustion, in which a part of nitroglycerin decomposes in the polymer matrix. Conversely, NG/PM monolithic and granular loads are not ignited by the explosion of the primer in a 9 mm calibre casing. The shockwave released by a detonator on a small NG/PM cylindrical charge (≈1.5 g) does not detonate it, but only makes it deflagrate. Our results show that this novel single‐step synthesis of NG trapped in a polymeric matrix is a very effective approach for desensitizing it to any form of stress. [ABSTRACT FROM AUTHOR]

Separation Distances are used throughout the world to protect people and assets from the potential hazardous effects from propellants, explosives, and pyrotechnics. The current separation distances for Hazard Division (HD) 1.3 substances and articles used in the United States, in some cases, may not adequately protect against the effects from heat flux and debris when those substances and articles are ignited in a confined structure. Multiple tests in such a confined scenario with HD 1.3 substances have shown that the heat flux and debris hazards could result in injury at distances beyond the current specified explosives safety separation distance (ESSD). Herein are the recommended ESSDs for confined as well as unconfined HD 1.3 articles and substances based on the analysis of hundreds of tests. Recommended ESSDs include a smaller value for unconfined quantities less than 145 kg and ESSDs that are consistent with NATO distances for confined substances and articles. [ABSTRACT FROM AUTHOR]

NEPE propellant has high energy and good mechanical properties. However, due to the lack of detailed research on its microscopic pyrolysis mechanism, the combustion rate and energy release rate are still difficult to control, which limits the further development of NEPE propellant. Based on this, quantum chemistry is used to study the pyrolysis mechanism of key components of NEPE propellant, including oxidants HMX and AP, binders PEG, NG and BTTN. The pyrolysis reaction path, rate-determining steps and main pyrolysis products of each component were calculated, and the pyrolysis kinetic parameters are calculated based on the transition state theory. The results show that HMX, BTTN and NG are all transformed into cyclic nitrogen compounds or chain carbon oxides by NO 2 or NO 3 shedding, and then gradually decomposed, while PEG is the gradual pyrolysis of long chain molecules. The main pyrolysis products are nitrogen oxides and various small fuel molecules containing C/H/N. The order of reaction rate constants of NEPE components is NG> AP> HMX> BTTN> PEG at 1500-2000 K. Among them, PEG and BTTN reaction rate constants are sensitive to temperature, and the reaction rate will rise rapidly with the increase of temperature. This study will provide an important theoretical reference for the regulation of NEPE high-energy catalyst pyrolysis behavior. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of National University of Defense Technology / Guofang Keji Daxue Xuebao is the property of NUDT Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Propellant gauging is crucial for a spacecraft approaching the end of its lifespan. Current gauging systems for satellites typically have an accuracy rate of a few months to a year at the end of their operational life. Therefore, it is essential to determine the appropriate gauging system for mission operations. This research focuses on modeling the propellant gauging system for PRISMA, an Earth Observation (EO) satellite of the Italian Space Agency. The analysis centers on implementing algorithms that calibrate the remaining propellant mass in the satellite tank using traditional methods such as bookkeeping (BKP) and pressure-volume-temperature (PVT). To enhance accuracy in quantification, an unconventional approach called thermal propellant gauging (TPG) has been considered. Preliminary computations were conducted using data obtained from the PRISMA thermal model to understand the calibration accuracy of the three methods. At the end of its operational life, the BKP and PVT methods exhibited error rates of 4.6% and 4.8%, respectively, in calculating the mass. In contrast, the TPG method demonstrated a significantly higher precision with an error rate of 1.86%. However, at the beginning of the satellite's operational life, the PVT and TPG methods showed error rates of 1.0% and 1.3%, respectively, while the BKP technique reported an error rate of 0.1%. Based on these findings, it has been concluded that combining the BKP and TPG approaches yields superior results throughout the satellite's lifespan. Furthermore, the researchers have determined the specific time duration for which each of these distinct approaches can be effectively utilized. [ABSTRACT FROM AUTHOR]

A series of fullerene anisole derivative stabilizers was synthesized by nucleophilic substitution reaction using hexachlorofullerene and benzyl alcohol as raw materials to extend the service duration of nitrocellulose (NC)-based propellants. Single-crystal X-ray diffraction, nuclear magnetic resonance, highresolution mass spectrometry, Fourier transform infrared (FT-IR) spectroscopy, and UVeVis spectroscopy were used to characterize the structures of the synthesized fullerene anisole derivative stabilizers. Methyl violet, differential scanning calorimetry test, isothermal weight loss, vacuum stability test, and adiabatic accelerated test were used to study their compatibility with NC and their ability to stabilize NC. The results show that the designed and synthesized novel fullerene anisole derivative stabilizer has good compatibility with NC, and their overall stabilizing effects on NC are better than those of the traditional stabilizers, diphenylamine (DPA), and N,N0-dimethyl-N,N0-diphenylurea (C2). The stabilizing effects was ranked as: 3b > 2d > 2a > 2c > C2 > 2b > DPA > NC. In addition, FT-IR analysis and electron spin resonance spectroscopy were applied to explore the stability mechanism of fullerene-based stabilizers to NC. The results reveal that the new fullerene stabilizer can adsorb and effectively eliminate the nitrogen oxide free radicals generated by NC degradation; therefore, it can forbid the autocatalytic degradation of NC and stabilize NC. [ABSTRACT FROM AUTHOR]

Fine porous ammonium perchlorate (PAP) has small holes in its crust, and the voids in the particles are connected to the outside. The porosity of PAP results in fine bubble contamination in a propellant because the voids in PAP cannot be completely charged with a binder. Fine bubble contamination can improve the burning rate characteristics of an ammonium perchlorate (AP) propellant. The influence of the porosity of PAP on the burning characteristics of an ammonium nitrate (AN)/AP propellant and the effect of Fe2O3 as a catalyst on them were investigated in this study. The void fraction of the propellant increased with increasing mass ratio between AP and all oxidizers (ξ) and ranged from 1.3 % to 3.2 %. The porosity of PAP increased the burning rate of AN/AP propellants. This effect increased with decreasing pressure and was independent of ξ. However, porosity had minimal influence on the burning rate of AN/AP propellants with Fe2O3. The effect of the catalyst on the increase in the burning rate due to the porosity of PAP was influenced by pressure and ξ. The effect on the AN/AP propellant was greatest when ξ was in the 0.5–0.6 range. [ABSTRACT FROM AUTHOR]

Glycidyl azide polymer (GAP)/Hexanitrohexaazaisowurtzitane (CL-20) composite propellants have significant advantages, such as high energy density and low characteristic signal. However, the lack of understanding of its ignition combustion and agglomeration mechanism limits its large-scale engineering application in solid rocket motors. In this paper, the ignition, combustion and agglomeration processes of GAP/CL-20 propellants were studied in detail by using modern analytical and testing instruments, such as high-speed cameras, CO2 laser ignition devices and laser particle size analyzers. First, the ignition and combustion process of the GAP/CL-20 composite propellant were observed with a high-speed camera, and its ignition and combustion mechanism were analyzed. On the basis of the BDP model, a multiple flame structure model suitable for the GAP/CL-20 composite propellant was proposed. Then, the agglomeration of aluminum particles in the combustion process of the GAP/CL-20 composite propellant was observed, and an agglomeration mechanism suitable for the GAP/CL-20 composite propellant was proposed based on the pocket model and skeleton layer theory. Subsequently, the particle size distribution, micromorphology and crystal structure of the condensed phase combustion products were analyzed. The particle size distribution of the condensed combustion products (CCPs) showed three modes, and the CCPs contained active aluminum, which indicated that aluminum particles were not fully oxidized during the combustion process of the propellant. Finally, several further research directions were proposed. The research results may have reference value for the engineering application of GAP/CL-20 propellants. [ABSTRACT FROM AUTHOR]

Fine porous ammonium perchlorate (PAP) has small holes in its crust, and the voids in the particles are connected to the outside. The porosity of PAP results in fine bubble contamination in a propellant because the voids in PAP cannot be completely charged with a binder. Fine bubble contamination can improve the burning rate characteristics of an ammonium perchlorate (AP) propellant. The influence of the porosity of PAP on the burning characteristics of an ammonium nitrate (AN)/AP propellant and the effect of Fe2O3 as a catalyst on them were investigated in this study. The void fraction of the propellant increased with increasing mass ratio between AP and all oxidizers (ξ) and ranged from 1.3 % to 3.2 %. The porosity of PAP increased the burning rate of AN/AP propellants. This effect increased with decreasing pressure and was independent of ξ. However, porosity had minimal influence on the burning rate of AN/AP propellants with Fe2O3. The effect of the catalyst on the increase in the burning rate due to the porosity of PAP was influenced by pressure and ξ. The effect on the AN/AP propellant was greatest when ξ was in the 0.5–0.6 range. [ABSTRACT FROM AUTHOR]

In this paper, a novel ionic liquid plasticizer, 1‐methyl‐4‐methoxyethyl‐1,2,4‐triazole dicyanamide ([MMET][DCA]), was synthesized and characterized. The effect of [MMET][DCA] on the viscous flow properties of HTPB was studied, and then the effect of [MMET][DCA] on the mechanical and thermal properties of the HTPB/TDI curing system was further explored. The results show that the hydrogen bond between [MMET][DCA] and HTPB has a significant effect on the viscosity of HTPB. In the HTPB/TDI curing system, when the di(2‐ethylhexyl)adipate (DEHA) was replaced by an equal amount of [MMET][DCA], the glass transition temperature did not change significantly; the tensile strength of the curing system increased from 0.436 MPa to 0.474 Mpa; the elongation at break increased from 506.2 % to 700.4 %, and the decomposition temperature at 5 % and 10 % mass loss increased by 32 °C and 70 °C, respectively. [ABSTRACT FROM AUTHOR]

Mathematical models for the simulation of the operation of various projectile-throwing systems are continuously modified, simultaneously with the development of propellants. For these models, properly determined values of energetic ballistic characteristics of propellants are very important. This paper presents an original test and the results of closed vessel comparative investigations. The study analyses specific combustion characteristics of single-base propellants using conventional black powder ignition, plasma ignition, and gas ignition. The results of the study indicate the need to take into account—in the calculation of the burning rate—not only the dynamics of gas pressure changes but also the real (experimental) form function, which differs from the theoretical one resulting from the assumed geometric burning model. The obtained results allow for a critical analysis of the existing methods used for the determination of values of ballistic characteristics of propellants. Further, it will allow for creating pyrostatic test conditions that would reflect the condition of instantaneous ignition of propellant grains over their entire surface in the most realistic way. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A mathematical model for the pre-cooling process was established to solve the problems of the long pre-cooling time and uncertain parameters of cryogenic propellant tanks. The pre-cooling parameters of a 300 m3 liquid hydrogen tank at several cooling rates were calculated and analyzed. The results show that the liquid hydrogen flow required to pre-cool the gas in the tank, tank wall, accessories, and interlayer thermal insulation materials increases first and then decreases and that the liquid hydrogen flow needed to offset the heat leakage gradually increases with the temperature reduction. When the average cooling rate rose from 0.1 K/min to 1 K/min, the pre-cooling time was shortened from 2730 min to 273 min, and the consumption of liquid hydrogen decreased from 2115 kg to 2091 kg. Among the various heat loads, the inner tank wall and accessories consumed the most significant proportion of liquid hydrogen, accounting for 87.84% to 88.61%. The cooling capacity was derived from the liquid hydrogen's evaporation and the cryogenic hydrogen gas's heating process, of which the liquid hydrogen accounted for 23.00%. Considering the principle of safe operation, it is recommended that stepped pre-cooling in two or three stages based on the maximum cooling rate is conducted. [ABSTRACT FROM AUTHOR]

The industrial nitrification system of preparing nitrocellulose (NC) adopts nitric and sulfuric mixed acid, which generates a large amount of waste acid and by‐products, and requires a laborious procedure for the stability treatment. In this study, a novel method was developed for the preparation of NC. NC with a nitrogen content of 12.62 % was prepared in 15 min by homogeneous esterification of cellulose based on [Bmim]Cl (1‐butyl‐3‐methylimidazolium chloride). The samples were characterized by FT‐IR, XRD, Raman, XPS, TG‐DSC, GPC, SEM, and elemental analysis. In addition, the activation energy (Ea) was calculated according to the Kissinger method. The burning rate and chemical stability of samples were also tested. The results showed that the NC had 3D honeycomb structure with pores of 200–300 nm diameter, uniform distribution of nitrogen elements, nitrogen content of 12.62 %, and minimum polydispersity index (PDI) of 1.55. The heat of decomposition (Qdec) released by the samples was increased by 141 J/g, the Ea decreased by 16.4 %, and the burning rate increased by 40.5 % when compared with commercially available NC12.6%. The chemical stability was very well only after water cooking. Compared with the conventional method, this method doesn't use sulfuric acid, generates less waste acid, and doesn't produce by‐products such as sulfate esters. The procedure of stability treatment was also very effortless. The costs could also be reduced by the recycling of ionic liquids. [ABSTRACT FROM AUTHOR]

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ballistics / Dandao Xuebao is the property of Journal of Ballistics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Stabilisers are added to gun and rocket propellants to react with species responsible for nitrate ester degradation during storage. The degradation products can be toxic and therefore harmful. There is a need to replace such stabilisers by "green" molecules and to study their degradation patterns through ageing. Propellant powders must remain chemically stable for a minimum of ten years when stored at temperatures equivalent to 25 °C [1]. α‐Tocopherol is a natural product that has been known for decades in other fields (Vitamin E) such as the pharmaceutical, food and cosmetics industries. It can act as a 'green' stabiliser" for smokeless powders because its heat flow is stable over time. In this paper, we characterise its stabilisation mechanism by identifying its main degradation products that could form within the propellant in an oxidising environment and in the presence of nitric acid. Liquid chromatography (LC) and gas chromatography (GC) separations are performed in order to dissociate the compounds formed during ageing. Compounds are then analysed by APCI‐timsTOF to obtain the molecular ion masses and then perform fragmentation spectra (MS/MS) to characterise their structure. In addition, using preparative HPLC‐UV, the degradation products are collected and analysed by NMR, with the aim of identifying the molecules. These identification methods help to unravel the stabilisation mechanism under accelerated ageing conditions. A time‐related fluctuation of the degradation products amounts is also observed, which indicates that the decomposition products also have a stabilisation effect. The three major α‐tocopherol degradation products are identified as: 2,3‐epoxy‐α‐tocopherylquinone, 5,6‐epoxy‐α‐tocopherylquinone and α‐tocored. [ABSTRACT FROM AUTHOR]

Concentrated GAP/AP propellant suspensions with different solid contents and molecular masses of GAP were prepared, in which diglycerol tetranitrate (DGTN) was the energetic plasticizer. The steady shear measurements were conducted using a rheometer to examine the influences of component characteristics, particle gradation and temperature on rheological behavior. Results indicate that the GAP/DGTN mixture is Newtonian viscous and concentrated GAP/AP suspensions are pseudoplastic fluids. The Ostwald ‐ De Waele model and the Arrhenius ‐ de Guzman equation are utilized to compare the pseudoplastic behavior and the viscosity‐temperature dependence of concentrated suspensions, respectively. The apparent viscosity is exponentially related to solid content and the pseudoplastic behavior gradually increases with solid content revealed by the decreasing power law index (n). Additionally, larger particle size of AP, smaller molecular mass of GAP, or lower temperature make possible the reduced apparent viscosity. Suitable particle gradation reduces the apparent viscosity to the desired value. [ABSTRACT FROM AUTHOR]

Copyright of Science Technology & Engineering is the property of Chinese Society of Technology Economics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Aero Weaponry is the property of Aero Weaponry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Some ammonium perchlorate composite propellants have an intermediate self-quenching pressure range around several MPa. When the propellant burns in a motor with an appropriate throat area, the motor changes its chamber pressure in dual combustion modes. The objective of this study is to make cyclic combustion-mode transitions and to achieve the thrust magnitude control of solid rocket motor. The transitions from the low mode to the high mode were attained by nitrogen gas injection, and those from the high mode to the low mode were done by a brief gas release with appropriate nitrogen gas injection. Without the gas injection, the transition from high mode to low mode was not accomplished and the combustion was interrupted. The timing to shut down the combustion gas release was important as well as the timing to inject the nitrogen gas. The valve timing was controlled according to the chamber pressure. Three time cyclic combustion mode transitions were accomplished. [ABSTRACT FROM AUTHOR]

Energetic oxetanes, a group of energetic binders (EBs), are the focus of this review. We briefly introduce the role of binders and the difference between EBs and traditional "non-energetic" polymer binders, followed by a discussion of the synthesis and key properties of polyoxetanes. Priority is given to recent works, but a long-term perspective is provided where necessary, to illustrate the development of this field and the most relevant emerging trends. New reports on methods of obtaining oxetane polymers are presented; concerning the possibility of using a new catalyst, water: Al(C4H9)3, or the ratio of comonomers on the properties of the obtained binders. The synthesis of copolymers with the use of polymers with an oxetane ring and polyethers, polybutadiene terminated with hydroxyl groups and poly (3-difluoroaminomethyl-3-methyloxetane) is discussed. The latest developments in crosslinking reactions and crosslinking agents used are also described. The primary challenges faced by the field are identified and a perspective on the future development of polyoxetane EBs is presented. [ABSTRACT FROM AUTHOR]

The propellant binder is one of the important components in three-component-based propellants. Three-component-based propellants contain oxidizer, binders, and additives. Refers to spesific impulse value and combustion rate, polyglycidyl nitrate is a very promising energetic polymer as a propellant binder. Polyglycidyl nitrate has the potential to be made from glycerol which is a waste of the biodiesel industry so that production costs are cheaper. This article discusses in depth the potential of polyglycidyl nitrate as a propellant energetic binder, including the composition of the propellant, the effect of the propellant binder on the properties of the propellant, the manufacture of polyglycidyl nitrate from glycerol, as well as the physical properties and thermodynamic data of Polyglycydyl nitrate. [ABSTRACT FROM AUTHOR]

Twenty years passed since the discovery of superconductivity in MgB2. Although there is much progress, the use of superconductors, in general, and of MgB2 in particular, remains limited. On the other hand, in the last 10 years MgB2 became a material of great interest for emergent applications, such as propellants, batteries, and catalysis, as a source material to obtain 2D borophene-like materials (e.g. BH borophane), biomedical field (taking advantage of its promising antimicrobial, antitumoral, biodegradable, and biocompatible features), heritage and ecology being the latest trends. These new directions place MgB2 as a material well integrated with nature cycles that can promote the concept of one eco- and health-friendly, with many envisioned practical purposes. This type of material is at the core of a clean and sustainable economy promoting new developments, boosting the older ones (e.g. superconductivity) and minimizing the costs for the transition to new and modern materials and technologies. In this work, we review recent trends and new directions of MgB2 applications and discuss their potential impact. [ABSTRACT FROM AUTHOR]

A computational and theoretical study of highly filled propellants was made. The dependences of the most important characteristics of propellant formulations (powder power, amount of gaseous products formed, combustion temperature) on the degree of filling with powerful explosives such as hexogen (RDX) and hexanitrohexaazaisowurtzitane (HNIW) were determined. The energy characteristics of promising propellants based on cellulose nitrates with the nitrogen content of 11.5% to 13.2% and a technological fluoropolymer additive F-42 were calculated using the REAL software. The calculated data allow choosing propellant compositions from a variety of formulation options with the set of thermodynamic characteristics (Tcomb from 1959 to 4327 K, FP from 443.7 to 1335 kJ/kg, with Mg from 27.2 to 46.4 mol/kg) required for solving a wide range of problems. [ABSTRACT FROM AUTHOR]