F
Francisco Nivaldo Aguiar Freire
Researcher at Federal University of Ceará
Publications - 53
Citations - 594
Francisco Nivaldo Aguiar Freire is an academic researcher from Federal University of Ceará. The author has contributed to research in topics: Dielectric & Dye-sensitized solar cell. The author has an hindex of 12, co-authored 49 publications receiving 507 citations. Previous affiliations of Francisco Nivaldo Aguiar Freire include State University of Ceará & Universidade Tecnológica Federal do Paraná, Medianeira.
Papers
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Structural and dielectric spectroscopy studies of the M-type barium strontium hexaferrite alloys (Ba x Sr 1−x Fe 12 O 19 )
F. M. M. Pereira,C. A. R. Junior,M Santos,R. S. T. M. Sohn,Francisco Nivaldo Aguiar Freire,José Marcos Sasaki,J. A. C. De Paiva,Antonio Sergio Bezerra Sombra +7 more
TL;DR: In this paper, the structural, dielectric and magnetic properties of the composite barium hexaferrite phases were discussed in view of applications as a material for permanent magnets, high density magnetic recording and microwave devices.
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Hydroxyapatite screen-printed thick films: optical and electrical properties
C.C. Silva,H.H.B. Rocha,Francisco Nivaldo Aguiar Freire,M. R. P. Santos,K. D. A. Sabóia,J.C. Góes,Antonio Sergio Bezerra Sombra +6 more
TL;DR: In this article, the structural and electrical properties of bioceramic hydroxiapatite (HA) thick films were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), infrared and Raman scattering Spectroscopy and electrical measurements.
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Experimental and numerical investigation of a ceramic dielectric resonator (DRA): CaCu3Ti4O12 (CCTO)
Ana Fabíola Leite Almeida,Ana Fabíola Leite Almeida,Ana Fabíola Leite Almeida,R.R. Silva,H.H.B. Rocha,Pierre Basílio Almeida Fechine,F.S.A. Cavalcanti,M.A. Valente,Francisco Nivaldo Aguiar Freire,R. S. T. M. Sohn,Antonio Sergio Bezerra Sombra +10 more
TL;DR: In this article, the CaCu3Ti4O12 (CCTO) phase was synthesized by microwave heating in a much shorter time compared to the conventional heating methods, and the results indicate that microwave processing is a promising method for preparing CCTO ceramics.
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Dehydrogenation of ethylbenzene with CO2 to produce styrene over Fe-containing ceramic composites
Jesuína Cássia Santiago de Araújo,Charllys B.A. Sousa,Alcemira C. Oliveira,Francisco Nivaldo Aguiar Freire,Alejandro Ayala,Alcineia C. Oliveira +5 more
TL;DR: In this paper, the activity of Fe-containing ceramic composites for the dehydrogenation of ethylbenzene in the presence of CO 2 was studied, and a low conversion was obtained using CaTiO 3, due to the loss of the Ca species and coke production.
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Structural and electrical properties of TeO2–V2O5–K2O glassy systems
TL;DR: In this article, the structural and electrical properties of the glassy system presented above were investigated by using X-ray diffraction (XRD), density measurement and Raman spectroscopy, while the glass transition temperature and thermal stability were determined by Differential Scanning Calorimeter.