Hiroto Habu

Bio: Hiroto Habu is an academic researcher from Japan Aerospace Exploration Agency. The author has contributed to research in topics: Propellant & Ammonium dinitramide. The author has an hindex of 10, co-authored 48 publications receiving 406 citations. Previous affiliations of Hiroto Habu include Yokohama National University.

Test of B/Ti multilayer reactive igniters for a micro solid rocket array thruster☆

Abstract: In this study, reactive B/Ti multilayer igniters were investigated for the noncontact ignition of a micro solid rocket array thruster in vacuum. When current is supplied to the B/Ti multilayer igniter, the chemical reaction: 2B + Ti → TiB 2 + 1320 cal/g occurs, and sparkles are spread to a distance of several millimeters or more. The B/Ti multilayer igniters with three sizes were fabricated, and tested in six configurations of solid propellant. Although one rocket with ignition charge was ignited successfully, the noncontact ignition of the solid propellant was not achieved. However, the B/Ti multilayer igniters themselves generated small impulses of 10 −6 N s order, suggesting the possibility of self-propulsion.

Kinetics analysis of thermal decomposition of ammonium dinitramide (ADN)

Abstract: Kinetics analyses were performed on the thermal decomposition of ammonium dinitramide (ADN) using thermogravimetry-differential thermal analysis–mass spectrometry–infrared spectroscopy (TG-DTA–MS–IR). The main evolved gases were determined to be NH3, H2O, N2, NO, N2O, and NO2. The apparent activation energies of the exothermic, mass-change and gas-evolving reactions were analyzed on the basis of Friedman methods. The apparent activation energy of evolving N2 has the same value as that of evolving H2O since they occur by the same mechanism. A Friedman plot obtained from the DTA data has a curve similar to those obtained from N2 and H2O. The reaction that generated N2 and H2O plays an important role in the exothermic reaction in the decomposition of ADN. The activation energy for the N2O evolution reaction has a range of approximately 120–152 kJ mol−1 with reaction progress values between 0.1 and 0.9. Quantum chemistry calculations revealed that the total energy barrier of dinitramic acid unimolecular decomposition and ammonium-dinitramic ions collision-induced decomposition is 149.9–156.0 and 160.6 kJ mol−1, respectively. These values are reasonable compared with the experimental value of 152 kJ mol−1.

Ionospheric disturbances induced by a missile launched from North Korea on 12 December 2012

Abstract: [1] Ionospheric disturbances caused by a missile launched from North Korea on 12 December 2012 were investigated by using the GPS total electron content (TEC). The spatial characteristic of the front edge of V-shaped disturbances produced by missiles and rockets was first determined. Considering the launch direction and the height of estimated ionospheric points at which GPS radio signal pierces the ionosphere, the missile passed through the ionosphere at heights of 391, 425, and 435 km at 0056:30, 0057:00, and 0057:30 UT, respectively. The observed velocities of the missile were 2.8 and 3.2 km/s at that time, which was estimated from the traveling speed of the front edge of V-shaped disturbances. Westward and eastward V-shaped disturbances propagated at 1.8–2.6 km/s. The phase velocities of the westward and eastward V-shaped disturbances were much faster than the speed of acoustic waves reported in previous studies, suggesting that sources other than acoustic waves may have played an important role. Furthermore, the plasma density depletion that is often observed following missile and rocket launches was not found. This suggests that the depletion resulting from the missile's exhaust was not strong enough to be observed in the TEC distribution in the topside ionosphere.

Thermal decomposition of the high-performance oxidizer ammonium dinitramide under pressure

Abstract: Ammonium dinitramide (ADN) is a promising new oxidizer for solid propellants because it possesses both high oxygen balance and high energy content, and does not contain halogen atoms. A necessary characteristic of solid propellants is chemical stability under various conditions. This study focused on the thermal decomposition mechanism of ADN under pressurized conditions. The pressure was adjusted from 0.1 to 6 MPa, while ADN was heated at a constant rate. The exothermal behavior and the decomposition products in the condensed phase during heating were measured simultaneously using pressure differential scanning calorimetry (PDSC) and Raman spectrometry. PDSC analyses showed the multiple stages of exotherms after melting. The exothermal behavior at low temperatures varied with pressure. Analysis of the decomposition products indicated that ammonium nitrate (AN) was generated during decomposition of ADN at all pressures. At normal pressure, AN was produced at the same time as start of exotherm. However, the temperature at which the ratio of ADN in chemical species in the condensed phase began to decrease under high pressure was higher than that at atmospheric pressure despite the existence of significant exotherm. At initial stage, thermal decomposition of ADN that does not generate AN was thought to be promoted by increased pressure.

Progress and Prospective of Nitrogen-Based Alternative Fuels.

Abstract: Alternative fuels are essential to enable the transition to a sustainable and environmentally friendly energy supply. Synthetic fuels derived from renewable energies can act as energy storage media, thus mitigating the effects of fossil fuels on environment and health. Their economic viability, environmental impact, and compatibility with current infrastructure and technologies are fuel and power source specific. Nitrogen-based fuels pose one possible synthetic fuel pathway. In this review, we discuss the progress and current research on utilization of nitrogen-based fuels in power applications, covering the complete fuel cycle. We cover the production, distribution, and storage of nitrogen-based fuels. We assess much of the existing literature on the reactions involved in the ammonia to nitrogen atom pathway in nitrogen-based fuel combustion. Furthermore, we discuss nitrogen-based fuel applications ranging from combustion engines to gas turbines, as well as their exploitation by suggested end-uses. Thereby, we evaluate the potential opportunities and challenges of expanding the role of nitrogen-based molecules in the energy sector, outlining their use as energy carriers in relevant fields.

Micro-chip initiator realized by integrating Al/CuO multilayer nanothermite on polymeric membrane

Abstract: We have developed a new nanothermite based polymeric electro-thermal initiator for non-contact ignition of a propellant. A reactive Al/CuO multilayer nanothermite resides on a 100 µm thick SU-8/PET (polyethyleneterephtalate) membrane to insulate the reactive layer from the silicon bulk substrate. When current is supplied to the initiator, the chemical reaction Al+CuO occurs and sparkles are spread to a distance of several millimeters. A micro-manufacturing process for fabricating the initiator is presented and the electrical behaviors of the ignition elements are also investigated. The characteristics of the initiator made on a 100 µm thick SU-8/PET membrane were compared to two bulk electro-thermal initiators: one on a silicon and one on a Pyrex substrate. The PET devices give 100% of Al/CuO ignition success for an electrical current >250 mA. Glass based reactive initiators give 100% of Al/CuO ignition success for an electrical current >500 mA. Reactive initiators directly on silicon cannot initiate even with a 4 A current. At low currents (<1 A), the initiation time is two orders of magnitude longer for Pyrex initiator compared to those obtained for PET initiator technology. We also observed that, the Al/CuO thermite film on PET membrane reacts within 1 ms (sparkles duration) whereas it reacts within 4 ms on Pyrex. The thermite reaction is 40 times greater in intensity using the PET substrate in comparison to Pyrex.