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Chemical Rocket Propellants
Published in D.P. Mishra, Fundamentals of Rocket Propulsion, 2017
Advanced oxidizers should have high density, high enthalpy of formation, high oxygen balance, and environmental compatibility. Ammonium dinitramide (ADN) is considered to be a promising oxidizer as it has higher heat of formation as compared to AP and chlorine-free combustion products. When it is mixed with energetic binders like GAP, it enhances specific impulse even at a lower solid loading of 80%. But it is not preferred as it has poor thermal stability and relatively high cost of production. Another advanced oxidizer is hexanitrohexaazaisowurzitane HNIW (CL20). It is one of the most powerful and dense single-component explosives. Although it is explosive by nature, it can be used in rocket propellant formulations in place of HMX. Hydrazinium nitroformate (HNF) is basically the salt of nitroform and hydrazine that is considered to be a promising oxidizer. This oxidizer with new energetic binders can have higher burn rates and specific impulse values as compared to conventional propellant. Many other energetic explosives with caged structure, namely, hydrazinium mono and diperchlorates, hydroxyl amine perchlorates, and difluramino compounds are being explored in order to enhance the performance of solid propellant. Interested readers can refer to advanced books on propellants and explosives [3].
Alloys and Environmental Related Issues
Published in Giacomo Giorgi, Koichi Yamashita, Theoretical Modeling of Organohalide Perovskites for Photovoltaic Applications, 2017
Fedwa El Mellouhi, Fahhad H. Alharbi, Carlo Motta, Sergey Rashkeev, Stefano Sanvito, Sabre Kais
Recently, Goldschmidt’s concept of the tolerance factor was extended (Kieslich et al. 2014, 2015) to account for the nonspherical cations. Similar to Goldschmidt’s initial approach, (effective) ionic radii were used for calculating the tolerance factor of hybrid perovskites. Protonated amines including [NH4]+ (ammonium), [NH3OH]+ (hydroxylammonium), [CH3NH3]+ (methylammonium), [NH3NH2]+ (hydrazinium), [(CH2)3NH2]+ (azetidinium), [CH(NH2)2]+ (formamidinium), [(C3N2H5]+ (imidazolium), [(CH3)2NH2]+ (dimethylammonium), [(CH3CH2)NH3]+ (ethylammonium), [(NH2)3C]+ (guanidinium), [(CH3)4N]+ (tetramethylammonium), [C3H4NS]+ (thiazolium), and [NC4H8]+ (3-pyrollinium) were treated as spheres with an effective radius rAeff. Highly asymmetric molecular anions such as HCOO–, CN–, and N3–, were treated as cylinders with effective height hXeff and effective radius rXeff for the cylinder, respectively. TFs of hybrid perovskites were calculated according to the generalized Goldschmidt equation,
Explosives and Propellants: Power to Breach Mountains, Wage war and Visit the Moon
Published in Richard J. Sundberg, The Chemical Century, 2017
Other related materials that have been considered as explosive oxidants are ammonium dinitramide, NH4+ [N(NO2)2]− and hydrazinium trinitromethide, NH2NH3+ [C(NO2)3]−. The salt of urea and nitric acid, known as both urea nitrate and uronium nitrate, was used in the 1993 bombing of the World Trade Center in New York. It can be used with aluminum, as well as hydrocarbon-based fuels. It is not very stable and this has limited its use in commercial explosives.
Redox cycling of copper mediated by hydrazine: efficient catalyst systems for oxidative degradation of rhodamine B
Published in Journal of Environmental Science and Health, Part A, 2021
Carlos Pedro G. do Nascimento, Ícaro O. Moreira, Tiago M. Freire, Pierre B. A. Fechine, Izaura C. N. Diógenes, Elisane Longhinotti
According to the species distribution diagram for hydrazine (Fig. S9), from pH 3.0 to 6.0, the hydrazinium ion (N2H5+) is the major species in solution. From pH 5.5 to 7.0, non-dissociated hydrazine is present in the medium thus favoring Eq. (3), even at low concentrations, and recovering the reduced state of the metal ions. These species, in turn, react fast with H2O2 (k = 104 M−1 s−1) producing HO•, which is the most likely active species regarding RhB degradation. Further increase of pH from 7.0 to 9.0 may lead to full reduction of the ions to the metallic state due to an increase in the hydrazine concentration, as indicated in Eq. (6):[40]