9 documents found, page 1 of 1
Structural, Morphological and Magnetic Properties of FeCo-(Fe,Co)3O4 Nanocompos...
Dias,Diego Felix; Braga,Tiago Pinheiro; Soares,João Maria; Sasaki,José MarcosFeCo nanoparticles coated with (Fe,Co)3O4 (magnetite doped with cobalt) were synthesized by the proteic sol-gel chemical route. The synthesized materials were characterized by Thermogravimetry (TG), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), vibrating-sample magnetometer (VSM) and Mössbauer spectroscopy (MS). The results show that the increase in tempera...
Lateritas do Domínio Médio Coreaú - comportamento geoquímico de mantos lateríti...
Siqueira,Ana Cláudia de Abreu; Magini,Christiano; Dantas,Elton Luis; Fuck,Reinhardt Adolf; Sasaki,José MarcosNeste trabalho é apresentada uma avaliação sobre a assinatura geoquímica dos principais elementos maiores em rochas lateríticas que ocorrem nos municípios de Granja, Martinópole e Parazinho, no Noroeste do Estado do Ceará. Geologicamente, a área está localizada no Domínio Médio Coreaú, caracterizada pelo Complexo Granja, representando o embasamento da região, composto por gnaisses, granulitos e migmatitos e por...
Synthesis of TiO2 by the pechini method and photocatalytic degradation of methy...
Ribeiro,Pollyana Caetano; Costa,Ana Cristina Figueiredo de Melo da; Kiminami,Ruth Herta Goldschmidt Aliaga; Sasaki,José Marcos; Lira,Hélio LucenaThis work evaluated the catalytic activity of TiO2 synthesized by the Pechini method. with varying molar ratios of 2:1, 3:1 and 4:1 of citric acid/metallic cations, in the photocatalytic degradation of methyl red dye in aqueous solution. The samples were characterized by X-ray diffraction, phase quantification by Rietveld structure refinement, and textural analysis by nitrogen adsorption, and their photocatalyt...
Estudo de coprólito da bacia sedimentar do Araripe por meios de espectroscopia ...
Lima,Ricardo Jorge Cruz; Freire,Paulo de Tarso Cavalcante; Sasaki,José Marcos; Saraiva,Antonio Álamo Feitosa; Lanfredi,SilvaniaCoprolites are fossilized faeces that constitute an important source of palaeobiological informations. This paper describes the characterization of some coprolite materials originated from the Romualdo Member of the Santana Formation (Araripe Basin, south of Ceará State in Brazil) by means of two techniques: X-ray powder diffraction and Fourier transform infrared spectroscopy (FT-IR). This characterization allo...
Caracterização espectroscópica de peixe do período cretáceo (Bacia do Araripe)
Lima,Ricardo Jorge Cruz; Saraiva,Antonio Alamo Feitosa; Lanfredi,Silvania; Nobre,Marcos Augusto de Lima; Freire,Paulo de Tarso CavalcanteThe study of fossils has made considerable progress over the last years as a result of the use of new experimental techniques. This paper describes the chemical composition of a fossilized fish of the Cretaceous period, from a 100 million-year-old, material originated from the Araripe Basin (northeastern Brazil). The chemical composition of the fossilized fish was analyzed by means of X-ray powder diffraction a...
Characterization by X ray diffraction of mechanically alloyed tripotassium sodi...
Miranda,Marcus Aurélio Ribeiro; Sasaki,José Marcos; Sombra,Antônio Sérgio Bezerra; Silva,Cléber Costa; Remédios,Cláudio Márcio RochaNanocrystalline powder of tripotassium sodium sulfate (K3Na(SO4)2 - KNS) was successfully obtained by mechanical alloying a mixture of potassium sulfate (K2SO4) and sodium sulfate (Na2SO4) with a proportion of 3:1 in a planetary mill. X ray powder diffraction (XRPD) was used to characterize this material. Powders produced with high milling times: 15, 30, 45 and 60 hours, have shown a single phase. For 60 hours ...
Taninos hidrolisáveis em Bixa orellana L.
Lima,Ricardo Jorge Cruz; Moreno,Antonio Jeferson de Deus; Castro,Solange Fernanda Loureiro de; Gonçalves,José de Ribamar SantosThe aqueous material found in the fruits of Bixa Orellana L. was collected, dried, and characterized using several experimental techniques, namely phytochemical analysis in order to identify the biologically active constituents, Fourier transform infrared (FT-IR) spectroscopy for vibrational analysis, and X-ray powder diffraction in order to identify the presence of crystalline phases in the sample. The results...
Magnetic properties of the granular alloy Fe10Ag90 as a function of annealing t...
Soares,João Maria; Araújo,José Humberto de; Cabral,Francisco de Assis Olímpio; Dumelow,Thomas; Xavier Júnior,Milton Morais; Sasaki,José MarcosFe10Ag90 granular alloys have been prepared using a sol-gel process, sintered at 300 °C and annealed at temperatures between 400 °C and 700 °C. The mean size of the iron particles, obtained from X-ray diffraction, is 30.0 ± 0.7 nm. Due to the existence of a distribution of particle sizes in these samples, both blocked (BL) and superparamagnetic (SPM) particles are present simultaneously, as confirmed by magneti...
X-ray scattering studies of the metastable ferroelectric phase in KDP induced b...
Remédios,Claudio Marcio Rocha; Miranda,Marcus Aurélio Ribeiro; Sasaki,José Marcos; Mendes-Filho,Josué; Freire,Paulo de Tarso CavalcantePotassium dihydrogen phosphate presents a ferroelectric phase below 122 K and a paraelectric phase for T > 122 K. X-ray scattering measurements were performed in order to verify the mechanism of the phase transition from point group C2v19 to C2v¹19 at 119 K induced by DC electric field; in other words, a change of the local site symmetries of the phosphate group occurs from C2 site in the C2v19 point group to C...