Synthesis and Piezoelectric Characterization of UV-Curable Nanocellulose/ZnO/AlN Polymeric Flexible Films for Green Energy Generation Applications

In this work, the fabrication of composites consisting of piezoelectric ZnO ceramic nanostructures and nanocellulose fillers in a UV-cured acrylic matrix has been exploited for the design of new functional coatings for green energy generation. The piezoelectric behavior was investigated at different accelerations applied to cantilever beams. The piezoelectric signal generated by the different ZnO nanostructures was improved by aluminum nitride film integration on the beam and proof mass insertion at the tip.

Searching for lepton flavor violating decays $$\tau \rightarrow Pl$$ in the minimal R-symmetric supersymmetric standard model

We analyze the lepton flavor violating decays $$\tau \rightarrow Pl$$ τ → P l ($$P=\pi ,\eta ,\eta ';\;l=e,\mu $$ P = π , η , η ′ ; l = e , μ ) in the scenario of the minimal R-symmetric supersymmetric standard model. The prediction on the branching ratios BR$$(\tau \rightarrow P e)$$ ( τ → P e ) and BR$$(\tau \rightarrow P \mu )$$ ( τ → P μ ) is affected by the mass insertion parameters $$\delta ^{13}$$ δ 13 and $$\delta ^{23}$$ δ 23 , respectively. These parameters are constrained by the experimental bounds on the branching ratios BR($$\tau \rightarrow e (\mu ) \gamma $$ τ → e ( μ ) γ ) and BR($$\tau \rightarrow 3e(\mu )$$ τ → 3 e ( μ ) ). The result shows Z penguin dominates the prediction on BR($$\tau \rightarrow Pl$$ τ → P l ) in a large region of the parameter space. The branching ratios for BR($$\tau \rightarrow Pl$$ τ → P l ) are predicted to be, at least, five orders of magnitude smaller than present experimental bounds and three orders of magnitude smaller than future experimental sensitivities.

Preliminary Study of Launch and Orbit of a CubeSat Using a Modified VSB-30 Launcher Vehicle

During the last decade, the world faced the mass insertion of small satellites in the space technology scenario. Every year, the number of micro and nanosatellites launched increases and gets more attention from players in the space market. Despite the lack of a national launcher, the Brazilian Space Program is known for some successful development in the last century, including its space assets, such as a privileged launch site near the equator, a family of flight proven and reliable sounding rockets for suborbital flights and microgravity experiments and universities with established small satellites programs. Thereby, the present work proposes a modification of the Brazilian VSB-30 sounding rocket in order to allow the launch and insertion in low Earth orbit (LEO) of small satellites fulfilling the gap of a national launcher. It also presents a CubeSat orbital decay simulation and orbital insertion simulation with the modified rocket launched from the Alcântara Launch Center as a matter of verifying the potential of national missions using this modified launcher.

Transient gas flow in elastic microchannels

We study pressure-driven propagation of gas into a two-dimensional microchannel bounded by linearly elastic substrates. Relevant fields of application include lab-on-a-chip devices, soft robotics and respiratory flows. Applying the lubrication approximation, the flow field is governed by the interaction between elasticity and viscosity, as well as weak rarefaction and low-Mach-number compressibility effects, characteristic of gaseous microflows. A governing equation describing the evolution of channel height is derived for the problem. Several physical limits allow simplification of the governing equation and solution by self-similarity. These limits, representing different physical regimes and their corresponding time scales, include compressibility–elasticity–viscosity, compressibility–viscosity and elasticity–viscosity dominant balances. Transition of the flow field between these regimes and corresponding exact solutions is illustrated for the case of an impulsive mass insertion in which the order of magnitude of the deflection evolves in time. For an initial channel thickness which is similar to the elastic deformation generated by the background pressure, a symmetry between compressibility and elasticity allows us to obtain a self-similar solution which includes weak rarefaction effects. The presented results are validated by numerical solutions of the evolution equation.