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- ItemOptimizing aerogravity-assisted maneuvers at high atmospheric altitude above Venus, Earth, and Mars to control heliocentric orbits(Rock Jeng-Shing Chern, 2024-02-01) Murcia Piñeros, Jhonathan; Bevilacqua, Riccardo; Prado, Antonio F.B.A.; Moraes, Rodolpho Vilhena de [UNIFESP]; http://lattes.cnpq.br/5577796502707425This paper analyzes the change in the heliocentric orbital elements due to the implementation of aerogravity and powered aerogravity assist maneuvers. Three cost functions were selected to maximize the planetocentric latitude, longitude, and velocity at the end of the atmospheric flight. An optimal control problem was solved to guide a spaceplane passing above the three inner planets: Venus, Earth, and Mars. The planets were selected because they have been relevant for gravity assists, and previous studies suggest that taking advantage of their atmospheres could increase the effects of the close approach. The research aims to analyze the variation in the heliocentric orbital elements of the trajectories after performing optimal aerogravity-assists and powered aerogravity-assisted maneuvers at high atmospheric altitudes. The trajectories were calculated via nonlinear programming to find the history of the control variables: angle of attack, bank angle, and thrust. Low-fidelity gravity and atmosphere models were implemented to evaluate this proof of concept. The optimization converged for all cases, and results show that maximization of the longitude increases the duration of the atmospheric flight, increasing the turning angle by almost twice the value of a single gravity assist. Furthermore, it reduces the energy and semimajor axis in half for approach angles between 20 and 90 degrees, saving more than 10 km/s on propulsion. Maximizing the velocity with propulsion increases the semimajor axis by more than 1.1 times the semimajor axis of the respective planet, and the optimal latitude presents a change in inclination of more than 1.0 degree. This maneuver could be applied to collect atmospheric samples or increase the coverage above the planet of interest. Those kinds of applications are described at the end of this paper, including a brief discussion on the maturity of this technology.
- ItemOptimization of Aero-gravity assisted maneuvers for spaceplanes at high atmospheric flight on Earth(American Institute of Aeronautics and Astronautics, 2024-01-08) Murcia-Piñeros, Jhonatha; Bevilacqua, Riccardo; Gaglio, Emanuela; Almeida Prado, Antonio F. B. de; Moraes, Rodolpho Vilhena de [UNIFESP]; http://lattes.cnpq.br/5577796502707425Gravity assists are impulse maneuvers that save costs for interplanetary missions, resulting from close approaches to celestial bodies. Aero-Gravity Assist maneuvers offer another solution to reduce mission cost by taking advantage of aerodynamic forces through cruise flights over the atmospheres of minor planets, like the Earth, which is selected because has been used on multiple gravity assist maneuvers. Despite their theoretical feasibility, the technological requirements make them impossible at low altitudes. Therefore, this work focuses on a spaceplane aeromaneuvering at high atmospheric altitudes and in continuum hypersonic flow, with Knudsen Numbers between 10-3 and 10-2. It is formulated as an optimal control problem with the dynamic optimization suite GEKKO, and solved via nonlinear programming. Nine different cost functions are analyzed separately: the maximization of longitude, latitude, and velocity at the end of the atmospheric flight; minimization of heat transfer, dynamic pressure, and load factor along the trajectory; minimization of flight time; and maximization of plane inclination and range angle. The results show a successful outcome in all cases, with a conclusive Monte Carlo analysis further demonstrating the robustness of the controller to support uncertainties in the initial conditions and atmospheric density
- ItemIdentification of yttrium oxide-specific peptides for future recycling of rare earth elements from electronic scrap(Wiley, 2024-01-02) Maass, Danielle [UNIFESP]; Boelens, Peter; Bloss, Christoph; Claus, Gerda; Harter, Sonja; Günther, Dominik; Pollmann, Katrin; Lederer, Franziska; http://lattes.cnpq.br/3431482044015696Yttrium is a heavy rare earth element that acquires remarkable characteristics when it is in oxide form and doped with other rare earth elements. Owing to these characteristics Y2O3 can be used in the manufacture of several products. However, a supply deficit of this mineral is expected in the coming years, contributing to its price fluctuation. Thus, developing an efficient, cost-effective, and eco-friendly process to recover Y2O3 from secondary sources has become necessary. In this study, we used phage surface display to screen peptides with high specificity for Y2O3 particles. After three rounds of enrichment, a phage expressing the peptide TRTGCHVPRCNTLS (DM39) from the random pVIII phage peptide library Cys4 was found to bind specifically to Y2O3, being 531.6-fold more efficient than the wild-type phage. The phage DM39 contains two arginines in the polar side chains, which may have contributed to the interaction between the mineral targets. Immunofluorescence assays identified that the peptide’s affinity was strong for Y2O3 and negligible to LaPO4:Ce3+,Tb3+. The identification of a peptide with high specificity and affinity for Y2O3 provides a potentially new strategic approach to recycle this type of material from secondary sources, especially from electronic scrap.
- ItemFiltering for Nonlinear and Linear Markov Jump Systems(Alessandro Astolfi, Zhan Shu, David Castanon, 2023-10-06) Costa, Oswaldo Luiz do Valle; Oliveira, André Marcorin de; http://lattes.cnpq.br/1864836114526818In this paper we consider the finite horizon filtering problem of discrete-time Markov jump systems (MJS). In the first part we consider a MJS satisfying some general nonlinear conditions. It is obtained, for a fixed set of auxiliary constants, filter gains, based on a set of coupled Riccati like difference equations, that yield a minimum upper bound for the estimation error covariance matrix. When the nonlinear parameters are set to zero the MJS becomes a Markov jump linear system (MJLS) and, in the second part of the paper, it is shown that the obtained filter gains derived from a set of coupled Riccati like difference equations provide the optimal “prediction-correction” Markovian filter for the nominal MJLS (which reduces to the standard Kalman filter for the no jump case). The paper is concluded with some numerical examples © 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
- ItemMixed Reduced Order Filtering for Discrete-Time Markov Jump Linear Systems with Partial Information on the Jump Parameter(Robert Kozma, 2023-06-21) Oliveira, André Marcorin de [UNIFESP]; Santos, Sérgio Ronaldo Barros dos [UNIFESP]; http://lattes.cnpq.br/1864836114526818This paper deals with the H2, H∞ and mixed H2/H∞ reduced-order filters for discrete-time Markov jump linear systems, within the context of partial observation of the jump parameter. It is considered that the Markov chain parameter, denoted by θ(k), is not observable but, instead, only an estimation, represented by ˆθ(k), is available for the filter design. Sufficient synthesis conditions for the filter design, based on linear matrix inequalities, are provided. These conditions for the H2 and H∞ filters are not conservative in the sense that, for the full-order case and perfect information of the Markov parameter, they become also necessary. Simplified conditions are derived for the Bernoulli case. The paper is concluded with an illustrative example in the context of networked control systems, in which we study the effects of reducing the order of the filter on the estimation performance.