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Hazards
Published in Rick Houghton, William Bennett, Emergency Characterization of Unknown Materials, 2020
Rick Houghton, William Bennett
Hydrazine (N2H4) is a clear, oily liquid resembling water in appearance and possesses a weak, ammonia-like odor. It may be in aqueous or anhydrous solution. Higher concentrations fume in air. The flash point of hydrazine is 38°C (100°F), and the flammable range is 4–100%. Hydrazine is detected by its high pH if even a minute amount of water is present. Colorimetric air monitoring tubes are available for hydrazine, although some do not discern hydrazine from ammonia and amines (all forming basic gas or vapor) because the tube detects basic pH.
Chemicals from Non-hydrocarbons
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
Hydrazine (N2H4 or H2NNH2) is a colorless, fuming liquid miscible with water, hydrazine (also called diazine) is a weak base but a strong reducing agent. Hydrazine is a colorless flammable liquid that has an ammonia-like odor and is highly toxic and dangerously unstable unless handled in solution as, e.g., hydrazine hydrate (NH2NH2xH2O).
Satellite Systems
Published in Jerry D. Gibson, The Communications Handbook, 2018
Ideally, a satellite in geostationary orbit should remain in a fixed position because the gravitational and centrifugal forces on it are equal. Unfortunately, the gravitational forces on a geostationary satellite are not constant. The gravitational forces of the sun and moon on a geostationary satellite cause a change in the inclination angle of the satellite. The station keeping subsystem in a satellite provides small thruster rockets that are periodically used to move the satellite back to an inclination angle of zero degrees. Orbital calculations also assume that the mass of the Earth is uniformly distributed in a perfect sphere. Actually, the Earth is slightly egg shaped. This error causes a change in the longitude of geostationary satellites. The station keeping subsystem is also used to keep geostationary satellites in their assigned longitudes. The thruster rockets used for station keeping use gas that is stored in tanks in the satellites. Hydrazine gas is often used for the thruster rockets on satellites. The amount of gas stored in the tanks for the thruster rockets is one of the limits on the effective lifetime of a geostationary satellite.
Experimental Investigations of Combustion: (95 WT.-%) HAN–Water Solution with High-SSA Activated Carbons
Published in Combustion Science and Technology, 2019
Meiram K. Atamanov, Rachid Amrousse, Keiichi Hori, Zulkhair Mansurov
At the end of the twentieth century, the promising alternative for hydrazine are a high energetic formulations such as: HAN, hydroxylamine nitrate (NH3OHNO3), HNF, Hydrazinium nitroformate (N2H5C(NO2)3), AND, Ammonium dinitramide (NH4N(NO2)2) etc. HAN - is a high energetic substance, which has good prospect as a substitute for hydrazine, and becomes very popular in the field of propellants (Amrousse et al., 2012a, 2015). This material is less toxic, has a high density and performance superior to most energy-intensive materials used and is regarded as the primary oxidant for hybrid rockets. HAN is a well-known chemical propellant, and many of its important thermodynamic and fluid dynamic characteristics have been characterized (Vosen, 1989). The flammability of HAN can be characterized as strongly dependent on the value of the initial pressure, which has a major effect on the speed and self-sustained combustion of the substance (Vosen, 1987). Also, the theory and model of HAN combustion was widely described in the work of Williams and Shaw (Williams and Shaw, 1992).
Influence of graphene oxide synthesis methods on the electrical conductivity of cotton/graphene oxide composites
Published in The Journal of The Textile Institute, 2022
Camilo Zapata-Hernandez, Geraldine Durango-Giraldo, Karen Cacua, Robison Buitrago-Sierra
Hummers’, the most widely adopted method to obtain graphite oxide, consists of oxidizing graphite using acid reagents, thus increasing the interlaminar distance, which is produced by decreasing Van der Waals forces. Subsequently, the product can be reduced by chemical or thermal methods. Hydrazine is commonly used as a reducing chemical agent; however, this reductant is toxic to the environmental and humans (Feng et al., 2013). For that reason, ascorbic acid has been proposed as an alternative to hydrazine, and it is currently being studied (Fernández-Merino et al., 2010; Xu et al., 2015). Large amounts of graphene oxide can be obtained employing Hummer’s method, but this requires hazardous and toxic chemicals during the synthesis process (He et al., 2019).
Synthesis of morphology controllable aluminum nitride by direct nitridation of γ-AlOOH in the presence of N2H4 and their sintering behavior
Published in Journal of Asian Ceramic Societies, 2018
Angga Hermawan, HyoungWon Son, Yusuke Asakura, Takao Mori, Shu Yin
Finally, the present method emphasized the possibility of the AlN powder synthesis with various unique morphologies at relatively low temperature by using morphology controllable γ-AlOOH as a precursor and hydrazine as a nitriding agent. Though experimentally promising, the hydrazine utilization may become a practical challenge, as it is toxic and flammable material. Thus, to increase the safety, the hydrazine solution can be supplied at a low concentration below the explosion limit.