A MEMS-based solid propellant microthruster array for space and military applications

Since combustion is an easy way to achieve large quantities of energy from a small volume, we developed a MEMS based solid propellant microthruster array for small spacecraft and micro-air-vehicle applications. A thruster is composed of a fuel chamber layer, a top-side igniter with a micromachined nozzle in the same silicon layer. Layers are assembled by adhesive bonding to give final MEMS array. The thrust force is generated by the combustion of propellant stored in a few millimeter cube chamber. The micro-igniter is a polysilicon resistor deposited on a low stress SiO2/SiNx thin membrane to ensure a good heat transfer to the propellant and thus a low electric power consumption. A large range of thrust force is obtained simply by varying chamber and nozzle geometry parameters in one step of Deep Reactive Ion Etching (DRIE). Experimental tests of ignition and combustion employing home made (DB+x% BP) propellant composed of a Double-Base and Black-Powder. A temperature of 250 therefore degrees C, enough to propellant initiation, is reached for 40 mW of electric power. A combustion rate of about 3.4 mm/s is measured for DB+20% BP propellant and thrust ranges between 0.1 and 3,5 mN are obtained for BP ratio between 10% and 30% using a microthruster of 100 mu m of throat wide

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Luminescence properties of ZnS:Mn nanocrystals embedded in SiO2 by ion implantation

International audienc

ZnTe precipitates formed in SiO2 by sequential implantation of Zn+ and Te+ ions

International audienc

Microstructure and microtexture evolution with aging treatment in an Al-Mg-Si alloy severely deformed by HPT

Experiments were conducted on an Al–0.6 % Mg–0.4 % Si alloy to evaluate the effect of different preliminary thermal treatments on the evolution of microstructure and microtexture during processing by High-Pressure Torsion (HPT). Disks of the alloy were solution-treated, then some disks were briefly aged at 473 K, and other disks were briefly aged at 523 K before processing by HPT for up to 20 complete revolutions. The processing by HPT refined the microstructure to an average grain size as small as ~0.25 ?m in the solution-treated alloy after 20 turns but preliminary aging led to slightly larger average grain sizes of ~0.35–0.40 ?m after 20 turns. For all processing conditions, there was a high fraction of high-angle grain boundaries after HPT and it is shown that aging introduces changes in the microtexture intensities.<br/

Ab initio study of GdCo5 magnetic and magneto-optical properties

The full potential linearized augmented plane wave method (FLAPW) including the spin-orbit coupling has been used to study the structural, electronic and magnetic properties of GdCo5 compound. The calculations were performed within the local spin density approximation (LSDA) as well as Coulomb corrected LSDA + U approach. The study revealed that the LSDA + U method gave a better representation of the band structure, density of states and magnetic moments than LSDA. It was found that the spin magnetic moment of Co (2c) and Co (3g) atoms in the studied compound is smaller compared to the one in bulk Co. The optical and magneto-optical properties and the magneto-optical Kerr effect have also been investigated

Ab initio study of GdCo5 magnetic and magneto-optical properties

The full potential linearized augmented plane wave method (FLAPW) including the spin-orbit coupling has been used to study the structural, electronic and magnetic properties of GdCo5 compound. The calculations were performed within the local spin density approximation (LSDA) as well as Coulomb corrected LSDA + U approach. The study revealed that the LSDA + U method gave a better representation of the band structure, density of states and magnetic moments than LSDA. It was found that the spin magnetic moment of Co (2c) and Co (3g) atoms in the studied compound is smaller compared to the one in bulk Co. The optical and magneto-optical properties and the magneto-optical Kerr effect have also been investigated.WOS:0004787844000062-s2.0-8506566204