Orbital Transfer
Mostrando 1-12 de 57 artigos, teses e dissertações.
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1. Synthesis, Characterization and Conformational Analysis of Two Novel 4(1H)‑Quinolinones
Quinolinones are a class of organic compounds known as alkaloids found in several plants and also can be synthesized. Their large use in therapies regards their wide biological potential like antitumor, psychiatric and neurological agents. Two substances were structurally characterized: (E)-3-(2-nitrobenzylidene)-2-(4-methoxyphenyl)-1-(phenylsulfonyl)-2,3-di
J. Braz. Chem. Soc.. Publicado em: 2020-01
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2. Synthesis, Photophysical and Electrochemical Properties of Novel D-π-D and D-π-A Triphenylamino-Chalcones and β-Arylchalcones
A series of triphenylamino (TPA)-chalcones and triphenylamino-β-arylchalcones, displaying either D-π-D or D-π-A architecture, were synthesized through aldol condensations and Heck reactions. The chalcone derivatives display intense absorption bands ranging from 389 to 432 nm and molar extinction coefficients of ca. 105 L mol-1 cm-1 corresponding to π-π*
J. Braz. Chem. Soc.. Publicado em: 2019-01
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3. Thermal Analysis of Satellite Libertad 2: a Guide to CubeSat Temperature Prediction
ABSTRACT: We present a model for predicting the temperature of three-unit CubeSat on a low Earth orbit, which supposes a single temperature common to all satellite components. Our exposition includes a detailed, to a large extent analytical, computation of the external heat fluxes for a particular orbit and spacecraft assumptions based on the features forese
J. Aerosp. Technol. Manag.. Publicado em: 08/11/2018
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4. N-Acetyl-cysteine Increases Chemical Stability of Hydroquinone in Pharmaceutical Formulations: a Theoretical and Experimental Approach
In this study, the chemistry stability of hydroquinone (HQ) was evaluated according to its effects in redox properties and compared to kojic acid (KA). The HQ oxidation was more inhibited by N-acetylcysteine (NAC) than ascorbic acid (AA). These results were elucidated using theoretical methods at the DFT/B3LYP level of theory. All electronic parameters were
J. Braz. Chem. Soc.. Publicado em: 2018-03
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5. Avaliação da Influência do Regime Térmico em Ambos os Lados da Junta na Soldagem Orbital
Resumo O objetivo do presente trabalho é a análise qualitativa da variação de temperatura em ambos os lados da junta soldada, de forma a verificar se esta variabilidade pode ter contribuído no aparecimento de descontinuidades, em destaque a falta de fusão lateral. O aparecimento da descontinuidade pode estar relacionado com a diferença de temperatura
Soldag. insp.. Publicado em: 05/01/2017
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6. Comparison of the Incident Solar Energy and Battery Storage in a 3U CubeSat Satellite for Different Orientation Scenarios
ABSTRACT In CubeSats, because the size is limited, the estimation of the incident solar energy according to the orbital parameters and satellite attitude is more critical for the design process of the electrical power system. This estimation is helpful either for sizing of the power sources and energy storage or for defining the operation modes of the CubeSa
J. Aerosp. Technol. Manag.. Publicado em: 2016-03
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7. Configuration Study of Structurally Integrated Thermal Protection Systems for a Sub-Orbital Platform
ABSTRACT: The atmospheric hypersonic flight of sub-orbital and space vehicles generates aerodynamic heating and high wall heat fluxes, inducing high temperatures on the vehicle's structures and affecting their mechanical behavior, besides degrading the operation of board equipment. Furthermore, since payload preservation is always mandatory, the use of effic
J. Aerosp. Technol. Manag.. Publicado em: 2015-06
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8. Thermal Protection System and Trajectory Optimization for Orbital Plane Change Aeroassisted Maneuver
ABSTRACT: The aim of this paper was to identify, for a specific maneuver, the optimal combination between the trajectory and the associated heat shield configuration, namely the locations and thicknesses of the ablative and reusable zones, that maximize the allowable payload mass for a spacecraft. The analysis is conducted by considering the coupling between
J. Aerosp. Technol. Manag.. Publicado em: 2013-03
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9. Distribuição da temperatura da superfície do mar e dos sedimentos suspensos na plataforma continental capixaba utilizando imagens landsat 5/TM
O monitoramento da qualidade da água nas regiões internas à Plataforma Continental (PC) apresenta-se dispendioso quando são usados métodos convencionais. O Sensoriamento Remoto Orbital apresenta-se como uma ferramenta alternativa ao monitoramento de variáveis importantes como a Temperatura da Superfície do Mar (TSM) e a Concentração de Sedimentos em
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/12/2012
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10. Pointing Algorithm for Reentry Orbit Injection with Uncontrolled Last Stage
Abstract: An essencial requirement for a launcher with uncontrolled last stage is to compute the ignition time of that stage and its attitude, in order to obtain a proper orbit transfer from a nonpropelled trajectory to a desired orbit, since such stage it cannot change its velocity profile and its direction. This article presents an algorithm that allows ac
J. Aerosp. Technol. Manag.. Publicado em: 2012-09
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11. Produção e otimização do processo de obtenção de ácido gama-poliglutâmico através do cultivo de Bacillus subtilis BL 53
O ácido y-poliglutâmico (y-PGA) é um biopolímero solúvel em água, aniônico, atóxico, biodegradável e biocompatível, produzido por Bacillus e que possui aplicações nas áreas química, médica, ambiental e de alimentos. Este trabalho tem como objetivo estudar o processo de produção do y-PGA a partir do cultivo de uma nova linhagem de Bacillus is
Publicado em: 2011
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12. Controle de trajetória orbital em manobras de empuxo contínuo de longo prazo / Control of orbital trajectory in maneuvers with continuous thrust of long term
Este trabalho considera o problema do controle da trajetória para manobras de transferência orbital utilizando um sistema propulsivo capaz de aplicar empuxo contínuo por um longo período de tempo. Foram analisadas não-idealidades dos propulsores e seus efeitos no sistema de controle durante a transferência orbital. Considerou-se um sistema de controle
Publicado em: 2009