Academia da Forca Aerea

Pirassununga, Brazil

Academia da Forca Aerea

Pirassununga, Brazil
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Souza J.D.L.,Academia da Forca Aerea | Souza J.D.L.,Federal University of São Carlos | Chiaregato C.G.,Federal University of São Carlos | Faez R.,Federal University of São Carlos
Journal of Polymers and the Environment | Year: 2017

Controlled release fertilizer (CRF) as a safe system for reducing environmental pollution still remains as demand for the agribusiness. Natural and biodegradable polymer materials have been proposed as a prominent and sustainable controlled delivery system. Composite based on polyhydroxybutyrate (PHB), starch, glycerol and montmorillonite (PHBSGMMt) has been proposed as a carrier for controlled release fertilizers, such as KNO3 and NPK. PHBSGMMt with 10 wt% of KNO3 or NPK processed by melting at 162 °C, 60 rpm during 10 min in a mixer chamber of torque rheometer. Composites were characterized according to its structure by FTIR and XRD, in thermal behavior by TGA and DSC, and morphology by SEM. Fertilizers release in water was determined by ionic conductivity. Clay, KNO3, and NPK increased the PHB/starch compatibility and homogeneity, resulting in a well-interfaced material obtained for PHBSGMMTNPK. MMtKNO3 was mainly on PHB phase and MMtNPK on the compatible polymeric phase. These behaviors explain the faster release of KNO3 in water medium since the KNO3 has high solubility and the phase separation creates fissures that turn in water pathway. Kinetic parameters classified the material as a non-Fickian diffusion or anomalous transport mechanism. © 2017 Springer Science+Business Media New York

Mendonca P.E.M.F.,Academia da Forca Aerea | Marchiolli M.A.,Avenida General Osorio 414 | Hedemann S.R.,PO Box 72
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2017

We consider the problems of maximizing the entanglement negativity of X-form qubit-qutrit density matrices with (i) a fixed spectrum and (ii) a fixed purity. In the first case, the problem is solved in full generality whereas, in the latter, partial solutions are obtained by imposing extra spectral constraints such as rank deficiency and degeneracy, which enable a semidefinite programming treatment for the optimization problem at hand. Despite the technically motivated assumptions, we provide strong numerical evidence that threefold degenerate X states of purity P reach the highest entanglement negativity accessible to arbitrary qubit-qutrit density matrices of the same purity, hence characterizing a sparse family of likely qubit-qutrit maximally entangled mixed states. © 2017 American Physical Society.

Bond V.L.,Arnold Air force Base | Canfield R.A.,Virginia Polytechnic Institute and State University | Da Luz Madruga Santos Matos M.,Academia da Forca Aerea | Suleman A.,University of Victoria | Blair M.,U.S. Air force
Journal of Aircraft | Year: 2010

Wind-tunnel tests were conducted to assess the use of aftwing twist for longitudinal control in a joined-wing aircraft Forces and moments required for pitch control were measured experimentally, along with limited chordwise pressure measurements. Comparisons of aerodynamic panel model predictions with experimental data were used to calculate camber and center-of-pressure corrections. The lift-curve slope measured at four flow speeds compared favorably to linear predictions over the range of 20° angles of attack. The pitching moment coefficient was linear at the three lower flow speeds for untwisted and twist-down aft wings over a narrower range of about 10° angles of attack. The pressure exhibited shifts in the chordwise distribution at angles of attack coinciding with the change in the moment curve slope. The large spread in the twist-up aftwing configuration drag and pitching-moment coefficients indicated flow separation on the aft wing, even at small angles of attack, deterring the twist effectiveness. Independent forward and aftwing measurements and more extensive use of pressure sensors are recommended in future experiments to confirm the apparent separation and interference effects that must be avoided if aftwing twist is to be used for pitch control on a joined wing.

Silva C.,Academia da Forca Aerea | Rocha B.,University of Victoria | Suleman A.,University of Victoria
Journal of Physics: Conference Series | Year: 2011

With the application of newer materials, such as composite materials, and growing complexity and capacity of current aircraft structures, reliably and completely assess the condition of the total structures in real time is then of growing and utmost importance. PZT Network and Phased Array, Lamb wave based Structural Health Monitoring (SHM) systems were developed to be applied to thin panels. The selection of transducers, their size and selected locations for their installation are described. The development and selection of the signal generation and data acquisition systems is also presented in detail. The requirements conducing to the development and selection of these systems are laid and particularly the selection of the actuation signal applied is justified. The development of a damage detection algorithm based in the comparison of the current structural state to a reference state is described, to detect damage reflected Lamb waves. Such method was implemented in software and integrated in the SHM system developed. Subsequently the detection algorithm, based in discrete signals correlation, was further improved by incorporating statistical methods. For phased arrays, a novel damage location algorithm is presented based on the individual sensors response. A visualization method based concurrently in the statistical methods developed and superposition of the different results obtained from a test set was implemented. These tests conducted to the successful and repeatable detection of 1mm damages in a multiple damaged plate with great confidence. Finally, a brief comparison and a hybrid system implementation is presented. © 2011 Published under licence by IOP Publishing Ltd.

Nascimento J.,Brazilian Technological Institute of Aeronautics | Pelegrini M.,Academia da Forca Aerea | Ferrao L.F.A.,Brazilian Technological Institute of Aeronautics | Roberto-Neto O.,Institute Estudos Avancados | MacHado F.B.C.,Brazilian Technological Institute of Aeronautics
Journal of the Brazilian Chemical Society | Year: 2011

Barrier heights of the internal rotation and inversion motions of methylamine, dimethylamine and trimethylamine molecules were calculated with the CCSD(T)//B3LYP methodology in combination with the cc-pVTZ, cc-pVQZ, and cc-pCVTZ basis sets of Dunning. The complete basis set (CBS) extrapolation procedure and core-valence (CV) correlation effects are also examined to the barrier heights. Our best estimate results (CCSD(T)/CBS+CV//B3LYP/cc-pVQZ) are in very good agreement with the experimental data, indicating the use of this methodology to provide accurate predictions of structures and barrier heights for other systems. © 2011 Sociedade Brasileira de Química.

Fanchini F.F.,Federal University of Ouro Preto | de Mendonca P.E.M.F.,Academia da Forca Aerea | Napolitano R.J.,University of Sao Paulo
Quantum Information and Computation | Year: 2011

We present a constructive argument to demonstrate the universality of the sudden death of entanglement in the case of two non-interacting qubits, each of which generically coupled to independent Markovian environments at zero temperature. Conditions for the occurrence of the abrupt disappearance of entanglement are determined and, most importantly, rigourously shown to be almost always satisfied: Dynamical models for which the sudden death of entanglement does not occur are seen to form a highly idealized zero-measure subset within the set of all possible quantum dynamics. © Rinton Press.

Wendland E.,University of Sao Paulo | Pizarro M.L.,Academia da Forca Aerea
Engenharia Agricola | Year: 2010

Study of water flow in the unsaturated soil zone is of great importance for research related to the water availability for crop development. Due to the high cost, the time required and the human effort in the field investigations, mathematical models combined with numerical techniques and computational advances are important tools in the prediction of these studies. This work aimed to solve the Richards's non-linear partial differential equation by applying the Finite Element Method. Adaptability with "h" refinement of the finite element mesh was used in the spatial approximation, while Explicit Euler scheme was applied for the time derivative. The polynomial interpolation function used was of degree two, and ensured the mass conservation of the adaptation strategy. To validate the model, data available in the literature were used. Use of the polynomial interpolation function with degree two and the "h" refinement, with considerable reduction of the computational runtime allowed good agreement in comparison to solutions available in the literature.

Mendonca P.E.M.F.,Academia da Forca Aerea | Mendonca P.E.M.F.,University of Queensland | Rafsanjani S.M.H.,University of Rochester | Galetti D.,São Paulo State University | Marchiolli M.A.,Avenida General Osorio 414
Journal of Physics A: Mathematical and Theoretical | Year: 2015

For every possible spectrum of 2N-dimensional density operators, we construct an N-qubit X-state of the same spectrum and maximal genuine multipartite (GM-) concurrence, hence characterizing a global unitary transformation that - constrained to output X-states - maximizes the GM-concurrence of an arbitrary input mixed state of N qubits. We also apply semidefinite programming methods to obtain N-qubit X-states with maximal GM-concurrence for a given purity and to provide an alternative proof of optimality of a recently proposed set of density matrices for the purpose, the so-called XMEMS. Furthermore, we introduce a numerical strategy to tailor a quantum operation that converts between any two given density matrices using a relatively small number of Kraus operators. We apply our strategy to design short operator-sum representations for the transformation between any given N-qubit mixed state and a corresponding X-MEMS of the same purity. © 2015 IOP Publishing Ltd.

Mendonca P.E.M.F.,Academia da Forca Aerea | Marchiolli M.A.,Avenida General Osorio 414 | Milburn G.J.,University of Queensland
International Journal of Quantum Information | Year: 2015

For every N-qubit density matrix written in the computational basis, an associated "X-density matrix" can be obtained by vanishing all entries out of the main-and anti-diagonals. It is very simple to compute the genuine multipartite (GM) concurrence of this associated N-qubit X-state, which, moreover, lower bounds the GM-concurrence of the original (non-X) state. In this paper, we rely on these facts to introduce and benchmark a heuristic for estimating the GM-concurrence of an arbitrary multiqubit mixed state. By explicitly considering two classes of mixed states, we illustrate that our estimates are usually very close to the standard lower bound on the GM-concurrence, being significantly easier to compute. In addition, while evaluating the performance of our proposed heuristic, we provide the first characterization of GM-entanglement in the steady states of the driven Dicke model at zero temperature. © 2015 World Scientific Publishing Company.

Marchiolli M.A.,Avenida General Osorio 414 | Mendonca P.E.M.F.,Academia da Forca Aerea
Annals of Physics | Year: 2013

We introduce a self-consistent theoretical framework associated with the Schwinger unitary operators whose basic mathematical rules embrace a new uncertainty principle that generalizes and strengthens the Massar-Spindel inequality. Among other remarkable virtues, this quantum-algebraic approach exhibits a sound connection with the Wiener-Khinchin theorem for signal processing, which permits us to determine an effective tighter bound that not only imposes a new subtle set of restrictions upon the selective process of signals and wavelet bases, but also represents an important complement for property testing of unitary operators. Moreover, we establish a hierarchy of tighter bounds, which interpolates between the tightest bound and the Massar-Spindel inequality, as well as its respective link with the discrete Weyl function and tomographic reconstructions of finite quantum states. We also show how the Harper Hamiltonian and discrete Fourier operators can be combined to construct finite ground states which yield the tightest bound of a given finite-dimensional state vector space. Such results touch on some fundamental questions inherent to quantum mechanics and their implications in quantum information theory. © 2013 Elsevier Inc.

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