Low Thrust
Mostrando 1-12 de 28 artigos, teses e dissertações.
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1. Distribution patterns of meiofauna on a tropical macrotidal sandy beach, with special focus on nematodes (Caixa d’Água, Amazon Coast, Brazil)
Abstract Spatial distribution patterns (both horizontal and vertical) of meiofauna, with special focus on nematodes, on a tropical macrotidal beach across different climatic periods were analyzed in this study. Samplings were carried out at five stations in the intertidal zone in June (rainy season) and December (dry season), 2011. At each station, three sam
Braz. j. oceanogr.. Publicado em: 13/06/2019
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2. Fatiga de contacto por rodadura en acero SAE 1050 recubierto con TiN, posteriormente templado
ABSTRACT The use of ceramic coatings of the nitride, carbide, or diamond type on steel substrates promotes the improvement of tribology properties. Nevertheless, high hardness gradients and adhesion problems may deteriorate the performance of these coatings when subjected to Rolling Contact Fatigue (RCF). Some studies on steels with ceramic coatings were car
Matéria (Rio J.). Publicado em: 19/07/2018
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3. On the Machinability and Surface Finish of Superalloy GH909 Under Dry Cutting Conditions
GH 909 alloy is a kind of low thermal expansion superalloy with high strength and low expansion coefficient. It is mainly used for manufacturing of aero-engine turbine casings, sealing ring, vanes and other gap control parts, to improve the working efficiency and thrust of the engine as well as to reduce gas loss and fuel consumption. However, the machinabil
Mat. Res.. Publicado em: 21/05/2018
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4. Analytical Solution for Optimal Low-Thrust Limited-Power Transfers Between Non-Coplanar Coaxial Orbits
ABSTRACT: In this paper, an analytical solution for time-fixed optimal low-thrust limited-power transfers (no rendezvous) between elliptic coaxial non-coplanar orbits in an inverse-square force field is presented. Two particular classes of maneuvers are related to such transfers: maneuvers with change in the inclination of the orbital plane and maneuvers wit
J. Aerosp. Technol. Manag.. Publicado em: 03/05/2018
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5. Low-temperature metamorphism in the Capiru Formation, Morro Grande Synform, Southern Ribeira Belt
ABSTRACT: The Capiru Formation consists of a low-grade meta-sedimentary succession of slates, phyllites, quartzites and marbles, disposed in blocks delimited by thrust and strike-slip faults in the Curitiba Terrane, Southern Ribeira Belt, Southern Brazil. The metamorphic and deformation records are heterogeneous, with deformed zones tectonically interbedded
Braz. J. Geol.. Publicado em: 2018-01
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6. Glass Microbeads in Analog Models of Thrust Wedges
ABSTRACT Glass microbeads are frequently used in analog physical modeling to simulate weak detachment zones but have been neglected in models of thrust wedges. Microbeads differ from quartz sand in grain shape and in low angle of internal friction. In this study, we compared the structural characteristics of microbeads and sand wedges. To obtain a better pic
An. Acad. Bras. Ciênc.. Publicado em: 2017-03
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7. Numerical Simulation of the Wake Structure and Thrust/Lift Generation of a Pitching Airfoil at Low Reynolds Number Via an Immersed Boundary Method
ABSTRACT: In this study, an accurate computational algorithm in the context of immersed boundary methods is developed and used to analyze an incompressible flow around a pitching symmetric airfoil at Reynolds number (Re = 255). The boundary conditions are accurately implemented by an iterative procedure applied at each time step, and the pressure is also upd
J. Aerosp. Technol. Manag.. Publicado em: 2015-09
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8. One-Stage Power Turbine Preliminary Design and Analysis
ABSTRACT: Design and development of gas turbine components are a complex multidisciplinary process. At the beginning of the power class definition and engine configuration it is necessary to conduct a market study. The results obtained are used in gas turbine thermodynamic cycle calculations and analysis in order to define the gas turbine design point. Sever
J. Aerosp. Technol. Manag.. Publicado em: 2015-06
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9. Development and Optimization of a Catalytic Thruster for Hydrogen Peroxide Decomposition
ABSTRACT: Hydrogen peroxide is a non toxic, low cost, green monopropellant with a significant potential for applications in satellite microthrusters. It presents a density-specific impulse similar to hydrazine. A new bulk mixed oxide catalyst for decomposition of hydrogen peroxide has been developed and tested in a 2 N thruster with modular parts, allowing t
J. Aerosp. Technol. Manag.. Publicado em: 2014-03
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10. Kick Solid Rocket Motor Multidisciplinary Design Optimization Using Genetic Algorithm
ABSTRACT: In this paper, a multidisciplinary design optimization (MDO) approach of a solid propellant kick rocket motor is considered. A genetic algorithm optimization method has been used. The optimized kick solid rocket motor (KSRM) is capable of delivering a small satellite of 200 kg to a circular low earth orbit (LEO) of 600 km altitude. The KSRM should
J. Aerosp. Technol. Manag.. Publicado em: 2013-09
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11. Análise do acoplamento entre o controle de atitude e de trajetória durante manobras orbitais de empuxo contínuo / Coupling analysis between attitude control and orbital maneuvering trajectory during continuous thrust
This work considers the coupling between attitude and orbit control used during an orbital transference which uses a continuous propulsive system capable impulse for a long time. The dynamic equations of movement are used to propagate the orbit and attitude states. It is studied some cases which comes from the effect of control during the orbital transferenc
Publicado em: 2010
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12. A Mechanism to Accelerate the Late Ablation in Pulsed Plasma Thrusters
Pulsed Plasma Thrusters (PPTs) are long standing electric propulsion thrusters that are reliable, relatively simple and low cost. One of the main issues with the PPT is its poor utilization of the propellant and low efficiency. Typically only 40-60% of the propellant contributes to the production significant impulse and the efficiency is around 8%. The cause
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 200902