Relationship between Laves phase and the impact brittleness of P92 steel reevaluated

Laves phase has been widely accepted to cause the impact brittleness of 9–12Cr martensitic heat-resistant steels after long time aging at elevated temperatures. However, in the present research, the impact toughness of the already brittle P92 steel aged at 600 °C for 2035 h could be restored to the original level by reheating at 700 °C for 1 h, with Laves phase barely changed. This interesting result strongly indicated that the presence of Laves phase might not be the real reason for the impact brittleness.

A atitude dos professores face à inclusão de alunos com deficiência : a influência do nível de ensino

RESUMO: A conjuntura actual veicula a necessidade de reflexão e de mudança acerca da concepção do modelo educativo, que se reformulam em novas realidades e ajustam a incumbência de adaptar. É certo que as necessidades de mudança devem partir de uma reflexão séria, fundamentando-se e difundindo o seu propósito em valores superiores. Estes desafios, que se cruzam na moralização social, tornam a discussão acerca do Paradigma Inclusivo substancial. O carácter quantitativo do estudo, assume o pressuposto de encontrar uma forma de monitorização de dados, decorrentes da aplicação de um inquérito por questionário, que para além da recolha de informações, visava também promover a reflexão dos professores, acerca das suas atitudes. Numa lógica de investigação em mosaico, obteve-se uma amostra total de 741 inquiridos, seleccionados no universo docente de forma aleatória. O tratamento estatístico foi desenvolvido por meio do suplemento EZanalyze, recorrendo-nos do teste paramétrico de análise de variância – ANOVA. Assim, pareceu-nos pertinente, centrar este estudo na figura activa do professor, no processo ensino-aprendizagem em contexto de sala de aula, propondo-nos a procurar eventuais analogias entre as variáveis Nível de Ensino e Grupo Disciplinar em estreita relação com a atitude dos docentes, relativas às vantagens da educação inclusiva, tanto para os alunos ditos normais como para os alunos portadores de deficiência, averiguando tanto a deficiência no seu âmbito geral, como especificando ainda a Deficiência Mental e a Deficiência Motora. Verificou-se que as variáveis Nível de Ensino e o Grupo Disciplinar influenciam directamente a atitude dos professores face aos benefícios para os alunos, que advêm da implementação do Paradigma Inclusivo. Verificou-se ainda que as vantagens que a inclusão proporciona, vão-se esbatendo à medida que o nível de ensino vai avançando. Naturalmente, destacam-se de forma positiva, os Educadores de Infância e os professores do 1º ciclo como os que se aproximam de atitudes mais inclusivas. Por sua vez constatou-se que as atitudes dos docentes do 2º ciclo ao ensino secundário evidenciavam atitudes bastante idênticas. ABSTRACT: The present context conveys the need for reflection and transformation on the educational model, which will reshape into new realities and readapt. It is true that the need for change must start from a serious enquiry, basing himself and his purpose on spreading higher standards. These challenges are intertwined in social moralizing which makes the discussion surrounding the Inclusive Paradigm substantial. The quantitative nature of the study, assumes the purpose of finding a way to monitor data from the application of a questionnaire that in addition to the collection of information, also aimed at promoting teachers reflection about their attitudes. In the logics of mosaic research, we obtained a total sample of 741 respondents, all of them were teachers selected at random. Statistical analysis was developed through EZanalyze, using the parametric test analysis of variance - ANOVA. Thus, it seemed appropriate that this study focused on the teacher's active figure on the teaching-learning process in the classroom, offering us a look for possible analogies between the variables Education Degree and Discipline Group in close relation with the teacher’s attitude concerning the advantages of inclusive education, for normal students as for students with disabilities, examining the deficiency within the general scope, such as specifying mentally and physical disabled. It was concluded that the variables Level of Education and Discipline Group directly influence teacher’s attitude, towards student’s benefits, coming from implementation of the Inclusive Paradigm. It was also concluded that the benefits of inclusion, are blurred as the education level progresses. Standing in a positive way, Early Childhood Educators and First Degree Teachers have more inclusive attitudes. Also, teachers from Second Degree to Secondary Degree has evidenced has being fairly homogeneous related to their attitudes towards the benefits of implementing a truly Inclusive Paradigm.

N3-Dye-Induced Visible Laser Anatase-to-Rutile Phase Transition on Mesoporous TiO(2) Films

Titanium dioxide has been extensively used in photocatalysis and dye-sensitized solar cells, where control of the anatase-to-rutile phase transformation may allow the realization of more efficient devices exploiting the synergic effects at anatase/rutile interfaces. Thus, a systematic study showing the proof of concept of a dye-induced morphological transition and an anatase-to-rutile transition based on visible laser (532 nm) and nano/micro patterning of mesoporous anatase (Degussa P25 TiO(2)) films is described for the first time using a confocal Raman microscope. At low laser intensities, only the bleaching of the adsorbed N3 dye was observed. However, high enough temperatures to promote melting/densification processes and create a deep hole at the focus and an extensive phase transformation in the surrounding material were achieved using Is laser pulses of 25-41 mW/cm(2), in resonance with the MLCT band. The dye was shown to play a key role, being responsible for the absorption and efficient conversion of the laser light into heat. As a matter of fact, the dye is photothermally decomposed to amorphous carbon or to gaseous species (CO(x), NO(x), and H(2)O) under a N(2) or O(2) atmosphere, respectively.

Preparation and characterization of PVDF/CaCO3 composites

The contribution of new materials, involving composites and blends, has been reaching the most varied fields of science, as much of the scientific as technological point of view. This is due to the man's needs in applications, especially in medicine areas. Thus, this work shows the preparation and characterization of poly(vinylidene fluoride) (PVDF) and calcium carbonate (CaCO3) Composite films in order to analyse the incorporation of CaCO3 in PVDF for future application in bony restoration and bony filling. The films were prepared by casting method, where the PVDF pellet shape was dissolved in dimethylacetamide (DMA) and in a separate container CaCO3/DMA emulsion was also made. Soon afterwards they were mixed in several proportions 100/00, 95/05, 85/15, 70/30 in weight and left to dry in greenhouse. Homogeneous and flexible films were obtained and structurally characterized by attenuated total reflection infrared spectroscopy (FT-IR/ATR), thermal analyses (DSC, TGA), X-ray diffractometry, optical and scanning electron microscopies. The results showed that the material was a composite with good thermal stability until around 400 degrees C, the crystallinity of PVDF was non-polar alpha-phase and the obtained films were porous, being these filled with CaCO3. (c) 2006 Elsevier B.V. All rights reserved.

Obtenção e caracterização do sistema compósito alginato de sódio-dióxido de titânio em formas de pó e de membrana

The alginates are copolymers of 1→4-linked β-D-mannuronic acid (M) and α-Lguluronic acid (G) residues that are arranjed in a block structure along a linear chain. Titanium dioxide, TiO2, is a ceramic material and can exist in three distinct crystallography forms: anatase, brookite and rutile. composites of organic and inorganic materials have better properties than the components alone. Thus, this study aims to synthesize, characterize and analyze the composite NaAlg-TiO2 in the form of powder and film. The synthesis of composite powders was performed using the sol-gel process and obtain the composite film was performed using the slow evaporation process, then the composites were analyzed by infrared spectroscopy, fluorescence x ray, thermal analysis, attenuated total reflection (ATR), x ray diffraction and impedance spectroscopy. The X ray diffraction patterns of composite powders show that with increasing calcination temperature, there were no complete transition of rutile-anatase crystalline phase, since at all temperatures studied (300, 500, 700, 900 and 1100ºC) were observed peaks of anatase phase. Thermal analysis shows that at 400°C caused the decomposition of sodium alginate in sodium carbonate and above 600°C, we observe an exothermic peak related to the decomposition of sodium carbonate and in the presence of titanium dioxide becomes sodium titanate. The XRD results confirm the formation of sodium carbonate at 700ºC and the formation sodium titanate in the temperature range 900-1100ºC. The sodium titanate influenced the electrical properties of the material, because with increasing temperature there was a decrease in conductivity, probably due to the creation of Ti vacancies, since the sodium can induce the reduction of surface Ti4+ ions into Ti3+ species. The infrared spectra of the composites in the form of powder and film showed a small shift in the bands compared to the spectrum of pure alginate, indicating that these shifts, even small ones, have evidence of miscibility between the polymer and ceramic material

Tetragonal to monoclinic phase transition observed during Zr anodisation

Plasma electrolytic oxidation (PEO) is a coating procedure that utilises anodic oxidation in aqueous electrolytes above the dielectric breakdown voltage to produce oxide coatings that have specific properties. These conditions facilitate oxide formation under localised high temperatures and pressures that originate from short-lived microdischarges at sites over the metal surface and have fast oxide volume expansion. Anodic ZrO2 films were prepared by subjecting metallic zirconium to PEO in acid solutions (H2C 2O4 and H3PO4) using a galvanostatic DC regime. The ZrO2 microstructure was investigated in films that were prepared at different charge densities. During the anodic breakdown, an important change in the amplitude of the voltage oscillations at a specific charge density was observed (i.e., the transition charge density (Q T)). We verified that this transition charge is a monotonic function of both the current density and temperature applied during the anodisation, which indicated that Q T is an intrinsic response of this system. The oxide morphology and microstructure were characterised using SEM and X-ray diffraction experiments (XRD) techniques. X-ray diffraction analysis revealed that the change in voltage oscillation was correlated with oxide microstructure changes during the breakdown process. © 2012 Springer-Verlag Berlin Heidelberg.

Análise multielementar da mucosa gástrica de roedores tratados com Alchornea glandulosa, Davilla elliptica e Davilla nitida pela técnica de fluorescência de raios-x por reflexão total

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Quantitative phase analysis from X-ray diffraction in Y-TZP dental ceramics: A critical evaluation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determinação da sensibilidade elementar de amostras-padrão pelo método de flurescência de raios X por reflexão total

To determinate the multielemental concentrations in biological samples using the technique of total reflection X-ray fluorescence (TRFX) is essential the use of standard samples. The aim of this study is the determination of the sensitivities of the relevant elements in standard samples (Multi Element atomic spectroscopy standard solution in HNO3 I) prepared in three solutions with different and known concentrations. Based on the sensitivities of the elements contained in the multilelementar standard sample, it can estimate the sensitivity for an element found in the biological sample and consequently it is possible to determinate the concentration, even though the standard does not contain this element. The measurement of fluorescence was performed at the Brazilian Synchrotron Light Laboratory (LNLS) in Campinas

Viabilidade do Código MCNPX para o Estudo da Técnica de Fluorescência de Raios-X por Reflexão Total

The X-ray fluorescence analysis (XRF) is an important technique for the qualitative and quantitative determination of chemical components in a sample. It is based on measurement of the intensity of the emitted characteristic radiation by the elements of the sample, after being properly excited. One of the modalities of this technique is the total reflection x-ray fluorescence (TXRF). In TXRF, the angle of refraction of the incident beam tends to zero and the refracted beam is tangent to the sample-support interface. Thus, there is a minimum angle of incidence that there is no refracted beam and all the incident radiation undergoes total reflection. As it is implemented in very small samples, in a film format, self-absorption effects should not very relevant. In this study, we evaluated the feasibility of using code MCNPX (Monte Carlo N - Particle eXtended), to simulate a measure implemented by the TXRF technique. In this way, it was verified the quality of response of a system by TXRF spectroscopy using synchrotron radiation as excitation beam for a simple setup, by retrieving the characteristic energies and the concentrations of the elements in the sample. The steps of data processing, after obtaining the excitation spectra, were the same as in a real experiment and included the obtaining of the sensitivity curve for the simulated system. The agreement between the theoretical and simulated values of Ka characteristic energies for different elements was lower than 1 % .The obtained concentration of the elements of the sample had high relatively errors ( between 6 and 60 % ) due mainly to lack of knowing about some realistic physical parameters of the sample , such as density . In this way, this result does not preclude the use of MCNPX code for this type of application

Caracterização morfológica e cristalográfica da zircônia após desgaste com pedra diamantada e elaboração de um protocolo para tratamento térmico regenerativo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Paper-based diffusive gradients in thin films technique coupled to energy dispersive X-ray fluorescence spectrometry for the determination of labile Mn, Co, Ni, Cu, Zn and Pb in river water

The diffusive gradients in thin films (DGT) technique has shown enormous potential for labile metal monitoring in fresh water due to the preconcentration, time-integrated, matrix interference removal and speciation analytical features. In this work, the coupling of energy dispersive X-ray fluorescence (EDXRF) with paper-based DGT devices was evaluated for the direct determination of Mn, Co. Ni, Cu, Zn and Pb in fresh water. The DGT samplers were assembled with cellulose (Whatman 3 MM chromatography paper) as the diffusion layer and a cellulose phosphate ion exchange membrane (Whatman P 81 paper) as the binding agent. The diffusion coefficients of the analytes on 3 MM chromatography paper were calculated by deploying the DGT samplers in synthetic solutions containing 500 mu g L-1 of Mn. Co, Ni, Cu, Zn and Pb (4 L at pH 5.5 and ionic strength at 0.05 mol L-1). After retrieval, the DGT units were disassembled and the P81 papers were dried and analysed by EDXRF directly. The 3 MM chromatographic paper diffusion coefficients of the analytes ranged from 1.67 to 1.87 x 10(-6) cm(2) s(-1). The metal retention and phosphate group homogeneities on the P81 membrane was studied by a spot analysis with a diameter of 1 mm. The proposed approach (DGT-EDXRF coupling) was applied to determine the analytes at five sampling sites (48 h in situ deployment) on the Piracicaba river basin, and the results (labile fraction) were compared with 0.45 mu m dissolved fractions determined by synchrotron radiation-excited total reflection X-ray fluorescence (SR-TXRF). The limits of detection of DGT-EDXRF coupling for the analytes (from 7.5 to 26 mu g L-1) were similar to those obtained by the sensitive SR-TXRF technique (3.8 to 9.1 mu g L-1). (C) 2012 Elsevier B.V. All rights reserved.

Total organic carbon content, methane isotopic composition and hydrocarbon characteristics of ODP Leg 180 sites

The organic geochemistry of Sites 1108 and 1109 of the Woodlark Basin, offshore Papua New Guinea, was studied to determine whether thermally mature hydrocarbons were present in the penetrated section and, if present, whether they are genetically related to the penetrated "coaly" interval. Both the organic carbon and pyrolysis data indicate that there is no significant hydrocarbon source-rock potential at Site 1108. The hydrocarbons encountered during drilling appear to be indigenous and not migrated products or contaminants. In contrast, the coaly interval at Site 1109 contains zones with significant hydrocarbon-generation potential. Several independent lines of evidence indicate that the coaly sequence encountered at Site 1109 is thermally immature. The Site 1108 methane stable-carbon isotope composition does not display a clear trend with depth as would be expected if it was solely reflecting a maturation profile. The measured isotopic composition of methane has most probably been altered by fractionation during sample handling and storage. This fractionation would result in isotopically heavier values than would be obtained on free gas. The organic geochemical data gathered indicate that Site 1108 can be safely revisited and that the organic-rich sediments encountered at Site 1109 were not the source of the gas encountered at Site 1108.