Brazilian Navy Research Institute

Rio de Janeiro, Brazil

Brazilian Navy Research Institute

Rio de Janeiro, Brazil
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Ferreira Filho I.L.,Brazilian Navy Research Institute | Mosso M.M.,Pontifical Catholic University of Rio de Janeiro
Microwave and Optical Technology Letters | Year: 2017

This article presents a methodology for the design of a more reliable printed microstrip Rotman lens based on the taper aperture that excites the lens and with the support of electromagnetic simulation software. Prototypes are developed on dielectric substrates (ɛr = 10.2) for phased array applications in frequencies of defense systems and radar (4–6 GHz) and of future 5G mobile systems (27–29 GHz). Return loss, isolation, and radiation pattern are simulated and measured showing the good performance of this methodology. © 2017 Wiley Periodicals, Inc.

Vianna M.L.,VM Oceanica LTDA | Menezes V.V.,Brazilian Navy Research Institute
Journal of Geophysical Research: Oceans | Year: 2011

We present here a study of the mean upper layer structure of the South Atlantic Subtropical Gyre (SASG) and its modes of variability based on Archiving, Validation, and Interpretation of Satellite Oceanographic data sea level anomaly data, Gravity Recovery and Climate Experiment-based mean dynamic topography (MDT) models, Reynolds sea surface temperatures, and two tide gauge time series from Permanent Service for Mean Sea Level. Analysis of the MDTs shows that the SASG mean structure is represented by a double-cell circulation, the southern cell being a narrow quasi-zonal strip centered around 33°S. Its southern limb is limited by the recently discovered Saint Helena Current/Tristan da Cunha Current (StHC/TCC) and the North Subtropical Front around 35°S. This system is shown to be well separated from the South Atlantic Current/South Subtropical Front around 42-45°S. A method based on singular spectrum analysis was used to determine the principal modes of variability through the decomposition of the data into band-passed data sets. The altimeter sea level trend analysis suggests that the SASG pattern is slowly migrating southward and has been growing in amplitude between 1994 and 2006 with local growth rates of 5-10 mm/yr occurring in the southern cell. Flow intensifications in this period (2-3 cm/s in the South Equatorial Current and North Brazil Undercurrent, 3.5 cm/s in the Benguela Current), and weakening by 4.5 cm/s in the StHC/TCC are recorded. The altimeter-derived sea level trend is coherent with the growing phase of a bidecadal oscillation found from both tide gauges. Copyright 2011 by the American Geophysical Union.

De Moraes Calazan R.,Brazilian Navy Research Institute | Nedjah N.,State University of Rio de Janeiro | De MacEdo Mourelle L.,State University of Rio de Janeiro
International Journal of High Performance Systems Architecture | Year: 2011

The particle swarm optimisation or PSO is a heuristic based on a population of individuals, in which the candidates for a solution of the problem at hand evolve through a simulation process of a social adaptation simplified model. Combining robustness, efficiency and simplicity, PSO has gained great popularity as many successful applications are reported. The algorithm has proven to have several advantages over other algorithms that are based on swarm intelligence principles. The use of PSO for solving problems that involve computationally demanding functions often results in low performance. In order to accelerate the process, one can proceed with the parallelisation of the algorithm and/or mapping it directly onto hardware. This paper presents a novel massively parallel co-processor for PSO implemented in reconfigurable hardware. The implementation results show that the proposed architecture is very promising as it achieved superior performance in terms of execution time when compared to the direct software execution of the algorithm. © 2011 Inderscience Enterprises Ltd.

Borges M.A.P.,Brazilian Navy Research Institute | Matos I.C.,Brazilian Navy Research Institute | Mendes L.C.,Federal University of Rio de Janeiro | Gomes A.S.,Federal University of Rio de Janeiro | Miranda M.S.,State University of Rio de Janeiro
Dental Materials | Year: 2011

Objectives: The aim of this study was to evaluate the degradation of different resin filling materials after a caries challenge, by high performance liquid chromatography (HPLC) and contact angle (θ) measurement. Methods: Four different polymeric restorative materials (a resin composite, a polyacid-modified resin composite, an ormocer and a resin-modified glass ionomer cement) were tested. Five samples (30 mm × 6 mm × 2 mm) of each material were formed in a Teflon mold, following the manufacturer's instructions. After pH cycles, the solutions were injected in an HPLC. The θ was obtained, before and after pH cycle, by a goniometer at 60% air humidity and 25 °C. A distilled water drop (0.006 ml) was put on the material surface, and after 6 min, 10 measures were obtained at 20 s intervals. Each sample received 4 drops, one at a time, on different areas. Results: HPLC results showed elution of byproducts in all materials. This was greater in the acid medium. Bis-GMA and TEGDMA were detected in TPH Spectrum and Definite residues. Analyses of the contact angle by ANOVA and Student-Neuman-Keuls's test showed that the surfaces of TPH Spectrum, Dyract AP and Definite were altered, except Vitremer (p < 0.05). Significance: All materials tested degraded on a caries simulated medium, suggesting that a great effort should be made to disseminate oral health information, since a high caries challenge environment (low pH) can lead to dental composite degradation, with potential toxic risks to patients. © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Pojucan M.M.S.,State University of Rio de Janeiro | Santos M.C.C.,Brazilian Navy Research Institute | Pereira F.R.,State University of Rio de Janeiro | Pinheiro M.A.S.,State University of Rio de Janeiro | Andrade M.C.,State University of Rio de Janeiro
Ceramics International | Year: 2010

This work evaluates the effect caused by the addition of Fe3+ and Nb5+ ions on the piezoelectric properties of lead zirconate titanate. Three compounds were obtained using the conventional method of mixture of oxides. The oxides were calcined at 850 °C and after that submitted to a uniaxial pressure of 70 MPa and an isostatic pressure of 200 MPa. Subsequently, the samples were sintered at 1200 and 1250 °C for 3.5 h. The surfaces were metalized and polarized in order to determine the piezoelectric properties. High concentration of dopants in lead zirconate titanate yielded high values of dielectric constant (K33 T) and specific mass. Moreover, there was an increase of the factor of electromechanical coupling (Kp) when compared to the pure PZT ceramics, associated with a decrease in the mechanic quality factor. © 2010 Elsevier Ltd and Techna Group S.r.l.

Filho W.S.,Brazilian Navy Research Institute | De Seixas J.M.,Federal University of Rio de Janeiro | De Moura N.N.,Federal University of Rio de Janeiro
IET Radar, Sonar and Navigation | Year: 2011

The noise radiated from ships in the ocean contains information about their machinery and can be used for detection and identification purposes. Here, a preprocessing method is developed in order to improve the performance of a feedforward neural network, which is used to classify four classes of ships. The entire system operates in the frequency domain over the information collected by the sensors of a passive sonar system. The effect of spectra averaging, resolution and background noise normalisation in the classifier performance is evaluated. Using preprocessed data to feed the input nodes of the classifier, a classification efficiency of about 97% has been achieved. © 2011 The Institution of Engineering and Technology.

Filho J.C.P.,Brazilian Navy Research Institute | Petraglia M.R.,Federal University of Rio de Janeiro
2014 International Telecommunications Symposium, ITS 2014 - Proceedings | Year: 2014

The DUET and TIFROM are the most widely used algorithms for separating anechoic mixtures in the underdetermined case (when the number of sources is larger than the number of sensors). Whereas the DUET algorithm requires that the sources are disjoint in the time-frequency domain, the TIFROM considers that there are regions in the time-frequency domain where the mixtures contain only one active source. Since both conditions are not always met in real scenarios, in this work two new algorithms are proposed such as to obtain good estimates of the attenuation and delay coefficients of each mixture without making use of such restrictions. The proposed methods employ binary masking, recursive estimates of the coefficients and sparsifying transforms in order to obtain improved solutions. © 2014 IEEE.

Filho I.L.F.,Brazilian Navy Research Institute | Mosso M.M.,Pontifical Catholic University of Rio de Janeiro
SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference Proceedings | Year: 2015

This paper presents a methodology for design a more reliable printed microstrip Rotman lens with the support of electromagnetic simulation software. A lens with four beam ports and four array ports in the range of 4 to 6 GHz is developed and manufactured with simulated and measured results of reflection coefficient, isolation and radiation pattern, showing a good performance of this methodology. © 2015 IEEE.

Ramos M.P.,Brazilian Navy Research Institute
Quintessence international (Berlin, Germany : 1985) | Year: 2012

Nowadays, necrotizing periodontal diseases have a low prevalence; however, a better understanding of the etiopathogenesis of these diseases is necessary for determining more adequate preventive and therapeutic strategies. From a pool of 1,232 HIV-infected patients, 15 presented with necrotizing periodontal diseases, which were evaluated by full-mouth periodontal clinical measurements. Subgingival biofilm samples were collected from necrotizing lesions of six of these individuals. The presence and levels of 47 bacterial species were determined by checkerboard DNA-DNA hybridization. All 15 patients (10 had severe immunodeficiency) had been infected sexually. Thirteen patients were taking antiretroviral medication (66.7% undergoing highly active antiretroviral therapy). Regarding necrotizing periodontal diseases, necrotizing ulcerative gingivitis (60%) was more prevalent than necrotizing ulcerative periodontitis (40%). The frequency of supragingival biofilm and bleeding on probing ranged from 11.5% to 59.2% and 3.0% to 54.0%, respectively, whereas the mean probing depth and clinical attachment level were between 1.48 and 2.61 mm and 1.30 and 2.62 mm, respectively. Species detected in high prevalence and/or counts in necrotizing lesions included Treponema denticola, Eikenella corrodens, Dialister pneumosintes, Enterococcus faecalis, Streptococcus intermedius, Aggregatibacter actinomycetemcomitans, and Campylobacter rectus. In contrast, Parvimonas micra, Prevotella melaninogenica, Fusobacterium nucleatum, Eubacterium nodatum, and Helicobacter pylori were observed in the lowest mean prevalence and/or counts. Necrotizing periodontal disease lesions in HIV-infected patients present a microbiota with high prevalence and/or counts of classical periodontal pathogens, in particular T denticola, as well as species not commonly considered as periodontal pathogens, such as E faecalis and D pneumosintes. In addition, these individuals with necrotizing periodontal disease frequently display severe immunodeficiency and AIDS-defining diseases such as tuberculosis.

Correa L.H.L.,Brazilian Navy Research Institute | Popoaski C.P.,Capivari de Baixo | Custodio G.,Hospital Santa Isabel in Blumenau | Goncalves C.O.,University of South Santa Catarina | Trevisol F.S.,University of South Santa Catarina
Anais Brasileiros de Dermatologia | Year: 2012

BACKGROUND - Skin cancer is the most common neoplasm in Brazil, with increasing incidence in recent decades. Data on the incidence of squamous cell carcinoma are scarce in southern Santa Catarina. OBJECTIVE: To establish epidemiological data on squamous cell carcinoma in Tubarão, State of Santa Catarina. METHODS: A cross-sectional review was conducted on anatomical pathology reports, positive for squamous cell carcinoma of the skin, found in the local laboratories. A convenience sampling method was used for data collection, since all the pathology reports from the local laboratories between 1999 and 2009 were included. The collected variables included year of diagnosis, age, gender, city of origin, tumor site, histological type and subtype, lesion size, margin involvement and relapse. RESULTS: In total, 1,437 case reports were identified, most frequently in individuals between 70 and 79 years old. Patient morbidity was 69.5 per 100,000 population for the year 1999, and 136.7 per 100,000 population for the year 2009, which represents a 50 percent increase. The face was the most affected area and the most common histological subtype was the well-differentiated tumor. CONCLUSION: There were 1,437 reports of squamous cell carcinoma of the skin between 1999 and 2009, with a significant increase in patient morbidity. There was an association between male gender and location on the lip and ear, and between females and the occurrence of squamous cell carcinoma of the skin on the nose, and upper and lower limbs. There was a prevalence of margin involvement after resection in 18% of lesions. © 2012 by Anais Brasileiros de Dermatologia.

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