Sounding
Mostrando 1-12 de 72 artigos, teses e dissertações.
-
1. Evaluation of OFDM Channel Sounding Techniques with Three Modulation Sequences
Abstract This paper presents an evaluation of multicarrier channel sounding techniques using different random and pseudo-random sequences to modulate the OFDM sounding signal. The Random (Rand), Pseudo-Noise (PN) and Zadoff-Chu (ZC) were tested, both in laboratory simulations and in field measurements. For the laboratory simulations Matlab routines were used
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 11/11/2019
-
2. Solidification Furnace Developed for Sounding Rockets: Rio Verde Mission
ABSTRACT Brazil has a Microgravity Program mainly based on experiments using sounding rockets. Up to now, four missions have been carried out with approximately 35 experiments submitted in total. In all flights, the Associate Laboratory of Sensors and Materials of the Brazilian Space Research Institute (LABAS/INPE) participated with a fast solidification fur
J. Aerosp. Technol. Manag.. Publicado em: 03/06/2019
-
3. Guerra de Xangô: ritual, perseguição e conflito na formação do campo religioso afro-sergipano
Resumo: O artigo procura investigar a formação do campo religioso afro-sergipano. Seu argumento central é de que, associados às práticas de “feitiçaria” e “bruxaria”, os adeptos das religiões afro-brasileiras eram por vezes envilecidos pela imprensa, perseguidos pelas forças de repressão e tratados como “fetichistas” pela Justiça. Neste
Relig. soc.. Publicado em: 16/05/2019
-
4. Shear Properties of Carbon Fiber/Phenolic Resin Composites Heat Treated at High Temperatures
ABSTRACT Carbon fiber/phenolic resin composites have long been used as ablative materials in rocketry. Ablation is a complex multiscale problem where radiative and convective heating leads to the pyrolysis of phenolic resin matrix, resulting in the formation of a porous insulation char as thermal protection. This study investigates the shear properties evolu
J. Aerosp. Technol. Manag.. Publicado em: 2016-09
-
5. Phase Noise Effects on Wideband Mobile Radio Channel Sounding
Abstract In this work three wideband mobile radio channel sounding methods are simulated and compared using computational tools. The considered sounders include the traditional STDCC and two other proposed sounding methods that are based on OFDM digital transmission and detection procedures and on matched filtering. The impact of the phase noise introduced b
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-12
-
6. The best of both worlds: Phylogenetic eigenvector regression and mapping
Eigenfunction analyses have been widely used to model patterns of autocorrelation in time, space and phylogeny. In a phylogenetic context, Diniz-Filho et al. (1998) proposed what they called Phylogenetic Eigenvector Regression (PVR), in which pairwise phylogenetic distances among species are submitted to a Principal Coordinate Analysis, and eigenvectors are
Genet. Mol. Biol.. Publicado em: 2015-09
-
7. Simulation of Ablation in a Sounding Rocket Thermal Protection System Via an Interface Tracking Method with Two Moving Fronts
ABSTRACT: In this work, an interface tracking method is employed to simulate the ablative process in the region near the stagnation point of the VSB-30 sounding rocket Thermal Protection System (TPS). The ablation model considers the presence of two-fronts, the char-melting and the pyrolysis fronts. The results for the proposed model are compared to the ones
J. Aerosp. Technol. Manag.. Publicado em: 2013-12
-
8. Comparison between OFDM and STDCC mobile channel sounders at 3.5 GHz
In this paper, we present a comparison between OFDM and STDCC sounding techniques used to wide band channel characterization in suburban environments at 3.5 GHz band. Measurements of the received signal's power delay profile and power level for each of the sounding techniques were obtained. These experimental results are presented and compared. For this comp
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
-
9. A Sensitivity Investigation on the Aeroelastic Dynamic Stability of Slender Spinning Sounding Rockets
ABSTRACT: The present work addresses a sensitivity analysis investigation of the aeroelastic stability margins for the VSB-30 sounding rocket during the atmospheric flight phase. Parametric stability analyses are performed considering variations of the inertia properties of the modular payload. Such variations can be caused by different type and/or number of
J. Aerosp. Technol. Manag.. Publicado em: 2013-03
-
10. Neotectonics in Marajó Island, State of Pará (Brazil) revealed by vertical electric sounding integrated with remote sensing and geological data
Estudos sugerem que a ilha do Marajó experimentou atividade neotectônica durante sua evolução final. Entretanto, não existem dados demonstrando a presença de estruturas tectônicas em subsuperfície. Este trabalho integra sondagem elétrica vertical, lineamentos morfoestruturais e dados geológicos objetivando mostrar que falhas controlaram a sedimenta
An. Acad. Bras. Ciênc.. Publicado em: 2013-03
-
11. Multidisciplinary Design Optimization of Sounding Rocket Fins Shape Using a Tool Called MDO-SONDA
Abstract: Multidisciplinary design optimization is a promising field in aerospace engineering. However, advances in this field have not been applied yet to improve Brazilian sounding rockets, such as the VS-40. Therefore, to give a perspective of the multidisciplinary design optimization in this context, this work presented a case study of this rocket, which
J. Aerosp. Technol. Manag.. Publicado em: 2012-12
-
12. Solidification Furnace for Microgravity Experiments on Sounding Rockets
Abstract: The Brazilian Microgravity Program is mainly based on experiments carried out on sounding rockets. Up to present days, three missions carrying a total of 25 experiments were made. In all flights, a fast solidification furnace, capable of producing temperatures up to 900º C, was used to process metal and semiconductor alloys in microgravity envir
J. Aerosp. Technol. Manag.. Publicado em: 2012-06