Array of carbon black-based microthrusters for CubeSat applications

Access to space for small private companies requires to improve the ability to bring low-cost satellites into orbit. CubeSats offer a unique opportunity to meet these needs thanks to their reduced production times, the low manufacturing costs and ease of use. In order to be able to communicate with each other, exchange information and interact, it is necessary to place CubeSats in formation: in this context, miniature propulsion technologies, including chemical and electric propulsion, play a critical role in achieving mission requirements and maintaining satellites position. In this article, the feasibility of solid propellant micro rockets, fully integrated in an opposing array of printed thrust chambers is examined: each rocket can be fired together with the others or separately to modulate thrust. Theoretical and experimental results show that the microthruster, made of nylon and carbon fiber, have good mechanical and thermal resistance and simultaneously good performance is achieved. In particular, a microthruster with a diameter of 4 mm and a length of 6 mm, with 55 g of black powder propellant, achieves a thrust of about 3.5 N for about 7 ms

Caratterizzazione di alcuni geni chiave per la produzione di metaboliti secondari in Passiflora incarnata ed Echinacea angustifolia. In Colture artificiali di piante medicinali.

Phenylalanine ammonia lyase (PAL; E.C.4.3.1.5.) is the gateway from primary metabolism into the important secondary phenylpropanoid metabolism in plant. PAL catalyses the non oxidative elimination of ammonia from L-Phe to give trans-cinnamate, a precursor of numerous phenylpropanoid compounds that fulfil various essential functions as mechanical supports (lignins), as protectans against biotic and biotic stresses, as pigment like the anthocyanins. Because of its key role in secondary phenylpropanoid metyabolism and secondary metabolites, PAL is one of the most extensively studied plant enzymes. A PAL gene, designed PaPAL, was isolated from Passiflora incarnata with a full length cDNA of 2384 nucleotides; a partial cDNA of 1987 nucleotides, named EcPAL, was obtained from Echinacea angustifolia roots. The expression analysis of the two genes revealed that the PaPAL gene is expressed in young leaves at the first stage of development, whilst the EcPAL is expressed only in the roots of Echinacea plants cultivated in hydroponic cultivation . These results indicate that the expression of PAL genes is highly regulated by the culture conditions and stage of development