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Registro Completo |
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Biblioteca(s): |
Embrapa Instrumentação. |
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Data corrente: |
21/06/2021 |
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Data da última atualização: |
10/06/2022 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
DIAS, J. A.; FREIRE, A. L. F.; GIROTTO, I.; DEL ROVERI, C.; MASTELARO, V. R.; PARIS, E. C.; GIRALDI, T. R. |
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Afiliação: |
ELAINE CRISTINA PARIS, CNPDIA. |
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Título: |
Phase evolution and optical properties of nanometric Mn-doped TiO2 pigments. |
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Ano de publicação: |
2021 |
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Fonte/Imprenta: |
Materials Today Communications, v. 27, e102295, 2021. |
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Páginas: |
1-12 |
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ISSN: |
2352-4928 |
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DOI: |
https://doi.org/10.1016/j.mtcomm.2021.102295 |
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Idioma: |
Inglês |
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Conteúdo: |
This paper aims to evaluate the effects of calcination temperature and manganese doping on optical properties and phase evolution of Mn-doped TiO2 pigments. The powders were prepared by the polymeric precursor method at Mn contents of 0, 1, 2 and 3 % and calcined at 600, 700 and 800 ◦C. The results demonstrated that crystalline powders were produced in all conditions evaluated. It was further noted that the samples calcined at 600 ◦C were composed of rutile and anatase TiO2 polymorphs. However, the anatase phase was completely converted into rutile at temperatures above 700 ◦C. The particle size increased with increasing temperature. The same behavior was observed for the measured crystallite sizes. The Mn3+ ion charge was determined as the main valence for manganese ions in the TiO2 host. Oxygen vacancies are the probable crystal defects formed for charge balancing in the Mn-doped rutile structure. The results obtained for the powder with 3 % Mn and calcined at 800 ◦C demonstrated dopant cation segregation to form Mn2O3. It is important to emphasize that the absorbance values of the powders increase in the visible range when adding manganese compared to the absorbance values of pure TiO2. The band gap of the powders was reduced in accordance with the content of doping: from 3.04 eV (0 % Mn) to 2.05–2.20 eV (3 % Mn), with small differences depending on the calcination temperature. The increase in visible light absorbance led to a brown color in Mn-doped materials. Thus, the color intensity varied with the Mn content, ranging from light brown to dark brown powders. In conclusion, the temperature of 700 ◦C was established in this paper as the best condition to produce Mn-doped TiO2 pigments, based on the absence of anatase polymorph, small contents of residual carbon, and undetectable amounts of Mn2O3 due to segregation MenosThis paper aims to evaluate the effects of calcination temperature and manganese doping on optical properties and phase evolution of Mn-doped TiO2 pigments. The powders were prepared by the polymeric precursor method at Mn contents of 0, 1, 2 and 3 % and calcined at 600, 700 and 800 ◦C. The results demonstrated that crystalline powders were produced in all conditions evaluated. It was further noted that the samples calcined at 600 ◦C were composed of rutile and anatase TiO2 polymorphs. However, the anatase phase was completely converted into rutile at temperatures above 700 ◦C. The particle size increased with increasing temperature. The same behavior was observed for the measured crystallite sizes. The Mn3+ ion charge was determined as the main valence for manganese ions in the TiO2 host. Oxygen vacancies are the probable crystal defects formed for charge balancing in the Mn-doped rutile structure. The results obtained for the powder with 3 % Mn and calcined at 800 ◦C demonstrated dopant cation segregation to form Mn2O3. It is important to emphasize that the absorbance values of the powders increase in the visible range when adding manganese compared to the absorbance values of pure TiO2. The band gap of the powders was reduced in accordance with the content of doping: from 3.04 eV (0 % Mn) to 2.05–2.20 eV (3 % Mn), with small differences depending on the calcination temperature. The increase in visible light absorbance led to a brown color in Mn-doped materials. Thus, the ... Mostrar Tudo |
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Palavras-Chave: |
Crystallinity; Doping; Rutile; Structure. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02635naa a2200277 a 4500
001 2132451
005 2022-06-10
008 2021 bl uuuu u00u1 u #d
022 $a2352-4928
024 7 $ahttps://doi.org/10.1016/j.mtcomm.2021.102295$2DOI
100 1 $aDIAS, J. A.
245 $aPhase evolution and optical properties of nanometric Mn-doped TiO2 pigments.$h[electronic resource]
260 $c2021
300 $a1-12
520 $aThis paper aims to evaluate the effects of calcination temperature and manganese doping on optical properties and phase evolution of Mn-doped TiO2 pigments. The powders were prepared by the polymeric precursor method at Mn contents of 0, 1, 2 and 3 % and calcined at 600, 700 and 800 ◦C. The results demonstrated that crystalline powders were produced in all conditions evaluated. It was further noted that the samples calcined at 600 ◦C were composed of rutile and anatase TiO2 polymorphs. However, the anatase phase was completely converted into rutile at temperatures above 700 ◦C. The particle size increased with increasing temperature. The same behavior was observed for the measured crystallite sizes. The Mn3+ ion charge was determined as the main valence for manganese ions in the TiO2 host. Oxygen vacancies are the probable crystal defects formed for charge balancing in the Mn-doped rutile structure. The results obtained for the powder with 3 % Mn and calcined at 800 ◦C demonstrated dopant cation segregation to form Mn2O3. It is important to emphasize that the absorbance values of the powders increase in the visible range when adding manganese compared to the absorbance values of pure TiO2. The band gap of the powders was reduced in accordance with the content of doping: from 3.04 eV (0 % Mn) to 2.05–2.20 eV (3 % Mn), with small differences depending on the calcination temperature. The increase in visible light absorbance led to a brown color in Mn-doped materials. Thus, the color intensity varied with the Mn content, ranging from light brown to dark brown powders. In conclusion, the temperature of 700 ◦C was established in this paper as the best condition to produce Mn-doped TiO2 pigments, based on the absence of anatase polymorph, small contents of residual carbon, and undetectable amounts of Mn2O3 due to segregation
653 $aCrystallinity
653 $aDoping
653 $aRutile
653 $aStructure
700 1 $aFREIRE, A. L. F.
700 1 $aGIROTTO, I.
700 1 $aDEL ROVERI, C.
700 1 $aMASTELARO, V. R.
700 1 $aPARIS, E. C.
700 1 $aGIRALDI, T. R.
773 $tMaterials Today Communications$gv. 27, e102295, 2021.
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Registro original: |
Embrapa Instrumentação (CNPDIA) |
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Biblioteca |
ID |
Origem |
Tipo/Formato |
Classificação |
Cutter |
Registro |
Volume |
Status |
URL |
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Registro Completo
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Biblioteca(s): |
Embrapa Amazônia Oriental. |
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Data corrente: |
26/07/1993 |
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Data da última atualização: |
16/07/2020 |
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Autoria: |
COSTA FILHO, P. P.; FERREIRA, C. A. P. |
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Afiliação: |
PERMINIO PASCOAL COSTA FILHO, CPATU; CELIO ARMANDO PALHETA FERREIRA, CPATU. |
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Título: |
Análise comparativa de custo de exploração florestal mecanizada em terra firme. |
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Ano de publicação: |
1991 |
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Fonte/Imprenta: |
Belém, PA: EMBRAPA-CPATU, 1991. |
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Páginas: |
20 p. |
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Série: |
(EMBRAPA-CPATU. Circular técnica, 63). |
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Idioma: |
Português |
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Conteúdo: |
Caracterização das áreas, obtenção dos dados, os cálculos, custos, receitas, avaliação econômica e área mínima de trabalho para avaliar a eficiência técnica da exploração mecanizada em terra firme, desenvolvidas no Campo Experimental de Curua-Una, Flora do Tapajós e Companhia Florestal Monte Dourado-Jari. |
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Palavras-Chave: |
Amapá; Aspectos economicos; Brasil; Campo experimental de Curua-Una; Companhia Florestal Monte Dourado; Comparacao; Cost; Exploitation; Exploracao; Floresta Nacional do Tapajós; Forest exploitation; Mecanization; Non flooded land; Para; Production; Terra firme; Wood extracts. |
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Thesagro: |
Custo; Economia; Exploração Florestal; Extração da Madeira; Floresta; Mecanização; Produção. |
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Thesaurus NAL: |
Amazonia; forestry; forests; mechanization. |
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Categoria do assunto: |
-- |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/34044/1/CPATU-CirTec63.pdf
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Marc: |
LEADER 01600nam a2200481 a 4500
001 1381201
005 2020-07-16
008 1991 bl uuuu u0uu1 u #d
100 1 $aCOSTA FILHO, P. P.
245 $aAnálise comparativa de custo de exploração florestal mecanizada em terra firme.
260 $aBelém, PA: EMBRAPA-CPATU$c1991
300 $a20 p.
490 $a(EMBRAPA-CPATU. Circular técnica, 63).
520 $aCaracterização das áreas, obtenção dos dados, os cálculos, custos, receitas, avaliação econômica e área mínima de trabalho para avaliar a eficiência técnica da exploração mecanizada em terra firme, desenvolvidas no Campo Experimental de Curua-Una, Flora do Tapajós e Companhia Florestal Monte Dourado-Jari.
650 $aAmazonia
650 $aforestry
650 $aforests
650 $amechanization
650 $aCusto
650 $aEconomia
650 $aExploração Florestal
650 $aExtração da Madeira
650 $aFloresta
650 $aMecanização
650 $aProdução
653 $aAmapá
653 $aAspectos economicos
653 $aBrasil
653 $aCampo experimental de Curua-Una
653 $aCompanhia Florestal Monte Dourado
653 $aComparacao
653 $aCost
653 $aExploitation
653 $aExploracao
653 $aFloresta Nacional do Tapajós
653 $aForest exploitation
653 $aMecanization
653 $aNon flooded land
653 $aPara
653 $aProduction
653 $aTerra firme
653 $aWood extracts
700 1 $aFERREIRA, C. A. P.
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