Síntese citrato-hidrotermal e caracterização eletroquímica de LSCF para aplicação como catodo em célula a combustível de temperatura intermediária

The lanthanum strontium cobalt iron oxide (La1-xSrxCo1-yFeyO3 LSCF) is the most commonly used material for application as cathode in Solid Oxide Fuel Cells (SOFCs), mainly due to their high mixed ionic electronic conductivity between 600 and 800ºC. In this study, LSCF powders with different compositions were synthesized via a combination between citrate and hydrothermal methods. As-prepared powders were calcined from 700 to 900°C and then characterized by X-ray fluorescence, X-ray diffraction, thermal analyses, particle size analyses, nitrogen adsorption (BET) and scanning electronic microscopy. Films of composition La0,6Sr0,4Co0,2Fe0,8O3 (LSCF6428), powders calcined at 900°C, were screen-printed on gadolinium doped ceria (CGO) substrates and sintered between 1150 and 1200°C. The effects of level of sintering on the microstructure and electrochemical performance of electrodes were evaluated by scanning electronic microscopy and impedance spectroscopy. Area specific resistance (ASR) exhibited strong relation with the microstructure of the electrodes. The best electrochemical performance (0.18 ohm.cm2 at 800°C) was obtained for the cathode sintered at 1200°C for 2 h. The electrochemical activity can be further improved through surface activation by impregnation with PrOx, in this case the electrode area specific resistance decreases to values as low as 0.12 ohm.cm2 (800°C), 0.17 ohm.cm2 (750°C) and 0.31 ohm.cm2 (700°C). The results indicate that the citrate-hydrothermal method is suitable for the attainment of LSCF particulates with potential application as cathode component in intermediate temperature solid oxide fuel cells (IT-SOFCs)

A Representação discursiva da figura feminina no jornal O Porvir (Currais Novos/Rio Grande do Norte - 1926-1929)

The objective of this paper is to analyze how the female figure was portrayed in discursive narratives in the bi-weekly newspaper O PORVIR , which circulated in Currais Novos, in the state of Rio Grande do Norte, Brazil, between May 2, 1926 and January 20, 1929. Our analysis was based on the semantics of the text, by applying one of the primary concepts used in Textual Analysis of Speeches, Discursive Representation (ADAM, 2011; RODRIGUES; PASSEGGI; SILVA NETO, 2010). Textual Analysis of Speeches has its roots in Textual Linguistics and consists of a theoretical and descriptive approach (ADAM, 2011). This research is characterized as documentary (SEVERINO, 2007) and its corpus includes a review of 39 editions of the aforementioned newspaper, of which we extracted 292 articles that dealt with the female figure and 396 statements for analysis. We used the following semantic categories: referencing (CASTILHO, 2010; NEVES, 2007; KOCH; MARCUSCHI, 1998; MARCUSCHI, 2008; KOCH, 2009); predication (NEVES, 2007; RODRIGUES; PASSEGGI; SILVA NETO, 2010); modification (ADAM, 2011); and spacial and temporal localization (RODRIGUES; PASSEGGI; SILVA NETO, 2010). Our analysis revealed that lady, mother, wife and homemaker were most represented, and always combined with questions about motherhood, marriage and devotion to the home. Such representation does not diverge from pre-colonial models in the early twentieth century, which served as a standard for the female figure

Prazer com razão: análise e crítica da ética sexual Kantiana

This work aims to present the foundations of Kantian ethics concerning to moral judgments about sexual practices. It shows that the sexual act, for the philosopher, inevitably degrades individuals who are taking part of it, given its objectifying nature, manifested in the usage of individuals as mere means to obtain pleasure. To solve this quandary of nature since humanity is an end in itself, by the virtue of being bearer of rationality and cannot, therefore, be treated as mere means Kant claims that marriage is morally the appropriate locus for the exercise of sexuality, given the reciprocity forged there, preventing degradation. In marriage, the bond established between the impulse of nature to the conservation of the species achieved through the sexual intercourse opened to procreation and the duty of man in regarding himself as an animal being preserving the species without degrading the person is accomplished in a fully moral way. This text clarifies that the justification for the assumption of this solution is fixed at two developments of the categorical imperative: the formulas of the law of nature and humanity. Despite the fact the first brings significant contributions to human relations through the concept of reciprocity, the second establishes a normative role for the teleological argument of sexuality, becoming an obstacle in kantian's practical philosophy. To overcome that obstacle, we outline a critics which relies on the studies of Michel Foucault about sex and the power techniques related to them, producer of a scientia sexualis in the Western, demonstrating that the moral of the philosopher from Königsberg is also present in this project somehow. Finally, in a foucaultian's reading of kantian Aufklärung, we recognize that, to propose new ethical possibilities of the experience of sexuality, it is necessary to think and create new relational spaces in which the subject takes autonomously the government of self.

Teias de caridade e o lugar social dos expostos da Freguesia de Nª Srª da Apresentação: capitania do Rio Grande do Norte, século XVIII

The abandonment of newborn children is a reality nowadays. This reality enables us to discuss this issue in other temporalities, in all kinds of societies. Thus, this work aims to demonstrate how the population that lived at Freguesia de Nossa Senhora da Apresentação, a civil parish at a Rio Grande do Norte captaincy, socially placed the abandoned newborn during in the eighteenth century. These newborn were called exposed ones at the time and were inserted in a regional Exposed Circle. The research also discussed how the local Council assembly sheltered these newborn. For research development the following manuscript documents were used: baptism, wedding and demise documents at Freguesia de Nossa Senhora da Apresentação as well as the first Book of Records if the matrix church at this civil parish. The research also considered the terms of the Council assembly. Some printed documents were used such as Philippine Ordainments, the First Constitutions of the Archbishop in 1707 including the Lunario contents as well as texts from André João Antonil and Henry Koster. In the analysis reference work related to Social History was used. Thus, it is possible confirm that there was construction of socially accepted places for these exposed on behalf of the colonist at the region

Seleção conjugal e as mulheres re-casadas no mercado de casamentos em uma comunidade de baixa renda no nordeste brasileiro

A presente pesquisa partiu de uma revisão teórica dos assuntos relacionados à seleção sexual proposta por Charles Darwin, passando para evolução dos sistemas e da psicologia do acasalamento humano. Os estudos práticos, divididos em dois momentos, foram coletados numa comunidade litorânea de baixa renda no nordeste brasileiro, na qual as mulheres tiveram pelo menos duas uniões estáveis até a data da coleta, no ano de 2008. Nas primeiras análises, foram contempladas as expectativas dessas mulheres em relação aos atributos dos parceiros. E posteriormente, o perfil e valor das mesmas entraram em perspectiva. De uma forma geral, foi constatado que as mulheres, no primeiro casamento, de fato realizam matrimônios com parceiros mais parecidos com o que consideram ideal do que os posteriores. Assim como as segundas e subseqüentes uniões apresentam uma ligeira queda no valor (no mercado de casamentos) desses homens quando comparados aos primeiros companheiros levando em consideração indicadores biosocioeconômicos como idade, escolaridade e renda (status socioeconômico).

Amor como medida de satisfação marital

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Investigação da estabilidade térmica e das propriedades elétricas do TiO2 em função da dopagem com Ce(SO4)2

The metalic oxides have been studies due to differents applications as materials semiconductor in solar cells, catalysts, full cells and, resistors. Titanium dioxide (TiO2) has a high electric conductivity due to oxygen vacancies. The Ce(SO4)2.2H2O doped samples TiO2 and TiO2 pure was obtained sol-gel process, and characterized by X-ray diffractometry,thermal analysis, and impedance spectroscopy. The X-ray diffraction patterns for TiO2 pure samples shows at 700°C anatase phase is absent, and only the diffraction peaks of rutile phase are observed. However, the cerium doped samples only at 900°C rutile in the phase present with peaks of cerium dioxide (CeO2). The thermal analysis of the TiO2 pure and small concentration cerium doped samples show two steps weight loss corresponding to water of hydration and chemisorbed. To larger concentration cerium doped samples were observed two steps weight loss in the transformation of the doped cerium possible intermediate species and SO3. Finally, two steps weight loss the end products CeO2 and SO3 are formed. Analyse electric properties at different temperatures and concentration cerium doped samples have been investigated by impedance spectroscopy. It was observed that titanium, can be substituted by cerium, changing its electric properties, and increased thermal stability of TiO2 anatase structure

Obtenção e Caracterização Físico-Química do Sistema Compósito PEG-TiO2

Hybrid systems formed from polymers and transition metals have now their physical and chemical properties extensively investigated for use in electronic devices. In this work, Titanium Dioxide (TiO2) from the precursor of titanium tetrabutoxide and the composite system Poly(Ethylene Glycol)-Titanium Dioxide (TiO2-PEG) were synthesized by sol-gel method. The PEG as acquired and TiO2 and composites powders were analyzed by X-Ray Diffraction (XRD), Spectroscopy in the Infrared region with Fourier transform (IRFT), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS). In the XRD analysis were observed in the TiO2 crystal faces of one of its polymorphs - anatase phase, crystal planes in Poly (Ethylene Glycol) with considerable intensity and in the composite systems the mixture of crystal faces of their precursors isolated and reduction of crystallinity. The TG / DTG suggested increasing the thermal instability of PEG in the composite powders as TiO2 is incorporated into the system. Spectral analysis presented in the infrared overlapping bands for the polymer and metal oxide, reducing the intensity of symmetric stretching of ligand groups in the main chain polymer and angular deformations; were observed using SEM micrographs of the morphological changes suffered by composite systems with the variation of the oxide concentration. Analyses by impedance spectroscopy indicated that the increased conductivity in composite occurs in line with the addition of the metal oxide concentration in the composite system

Estudo da eficácia do tensoativo sorbitano tween 80 veiculado em nanoemulsão contendo óleo de soja, como inibidor de corrosão

Nowadays, the use of chemicals that satisfactorily meet the needs of different sectors of the chemical industry is linked to the consumption of biodegradable materials. In this context, this work contemplated biotechnological aspects with the objective of developing a more environmentally-friendly corrosion inhibitor. In order to achieve this goal, nanoemulsion-type systems (NE) were obtained by varying the amount of Tween 80 (9 to 85 ppm) a sortitan surfactant named polyoxyethylene (20) monooleate. This NE-system was analyzed using phase diagrams in which the percentage of the oil phase (commercial soybean oil, codenamed as OS) was kept constant. By changing the amount of Tween 80, several polar NE-OS derived systems (O/W-type nanoemulsion) were obtained and characterized through light scattering, conductivity and pH, and further subjected to electrochemical studies. The interfacial behavior of these NE-OS derived systems (codenamed NE-OS1, S2, S3, S4 and S5) as corrosion inhibitors on carbon steel AISI 1020 in saline media (NaCl 3.5%) were evaluated by measurement of Open Circuit Potential (OCP), Polarization Curves (Tafel extrapolation method) and Electrochemical Impedance Spectroscopy (EIS). The analyzed NE-OS1 and NE-OS2 systems were found to be mixed inhibitors with quantitative efficacy (98.6% - 99.7%) for concentrations of Tween 80 ranging between 9 and 85 ppm. According to the EIS technique, maximum corrosion efficiency was observed for some tested NE-OS samples. Additionaly to the electrochemical studies, Analysis of Variance (ANOVA) and Principal Component Analysis (PCA) were used, characterization of the nanoemulsion tested systems and adsorption studies, respectively, which confirmed the results observed in the experimental analyses using diluted NE-OS samples in lower concentrations of Tween 80 (0.5 1.75 ppm)

Obtenção e caracterização físico-química de blendas poliméricas, baseadas em POE e PMMA, dopadas com dióxido de titânio

The study of polymer blends has been an alternative method in the search field of new materials for obtaining materials with improved properties. In this work blends of poly(methyl methacrylate) (PMMA) and poly(ethylene oxide) (PEO) doped with titanium dioxide (TiO2) were studied. The PEO is a polymer semicrystalline structure varying between, 70 and 84% crystallinity, while the PMMA exhibits behavior amorphous in their structure. The use of TiO2 is related to corrosion-resistant of titanium as well as good heat transfer and other characteristics. The study of these polymer blends doped TiO2 gives the properties junction organic (polymer) and inorganic (oxide) which leads to modification of the properties of the resultant material. The blends were doped TiO2 (POE/PMMA/TiO2) in different proportions of the PMMA with the PEO and TiO2 fixed. The ratios were: 90/10/0,1; 85/15/0, 1; 80/20/0,1, 75/25/0,1 and 70/30/0,1. The resulting material was obtained in powder form and being characterized by Fourier Transformed Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Electrochemical Impedance Spectroscopy (EIS). The infrared spectra (IR) for the blends in different ratios showed a band at 1744 cm-1, characteristic of the C=O stretching, which increases in intensity with increasing PMMA composition, while in the spectrum of pure PEO this band is absent. This may suggest that the interaction is occurring between the polymers. In the micrographs of the blends also observed change in their surfaces with variation of the composition of PMMA, contributing to the change of the electrical properties of the material. The EIS data showed that the material exhibited conductivity of the order of 10-6 S.cm-1. The blend in the ratio B2(85/15/0, 1) showed better conductivity, σ = 1.56 x 10-6 S.cm-1. It was observed that the diffusion coefficient for the blends, B5(70/30/0, 1) was the largest, 1.07 x 10-6 m2.s-1. The XRD data showing that, with the variation in the composition of the PMMA blend crystallinity of the material is decreased reaching a minimum B3(80/20/0,1), and then increases again. Thermal analysis suggests that blends made from the material obtained can be applied at room temperature

Confecção e caracterização físico-química de filmes compósitos autossustentáveis NaAlg-TiO2-WO3

A new self-sustainable film was prepared through the sol-gel modified method, previously employed in our research group; sodium alginate was used as the polymer matrix, along with plasticizer glycerol, doped with titanium dioxide (TiO2) and tungsten trioxide (WO3). By varying WO3 concentration (0,8, 1,6, 2,4 and 3,2 μmol) and keeping TiO2 concentration constant (059 mmol), it was possible to study the contribution of these oxides on the obtained films morphological and electrical properties. Self-sustainable films have analyzed by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XDR), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Electrochemical Impedance Spectroscopy (EIS). By the IR specters, it was possible identify the TiO2, and posteriorly WO3, addition has provided dislocation of alginate characteristics bands to smaller vibrations frequencies indicating an electrostatic interaction between the oxides and the polymer matrix. Diffractograms show predominance of the amorphous phase in the films. SEM, along with EDX, analysis revealed self-sustainable films showed surface with no cracks and relative dispersion of the oxides throughout the polymer matrix. From Impedance analysis, it was observe increasing WO3 concentration to 2,4 μmol provided a reduction of films resistive properties and consequent improvement of conductive properties

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

Comparação de desempenho da deconvolução preditiva multicanal e da filtragem f-k na atenuação de múltiplas do fundo do mar

The seismic reflection is used on a large scale in oil exploration. In case of marine acquisition the presence of high impedance contrast at the interfaces water/air generates multiple reflections events. Such multiple events can mask primary events; thus from the interpretational viewpoint it is necessary to mitigate the multiples. In this manuscript we compare two methods of multiple attenuation: the predictive multichannel deconvolution (DPM) and the F-K filtering (FKF). DPM is based in the periodicity of the multiples while FKF is based in multiples and primaries splitting in F-K domain. DPM and FKF were applied in common-offset and CDP gathers, respectively. DPM is quite sensible to the correct identification of the period and size of the filter while FKF is quite sensible to an adequate choice of the velocity in order to split multiples and primaries events in the F-K domain. DPM is a method that is designed to act over a specific event. So, when the parameters are well selected, DPM is very efficient in removing the specified multiple. Then DPM can be optimized by applying it several times, each time with a different parameterization. A deficiency of DPM occurs when a multiple is superposed to a primary event: in this situation, DPM can attenuate also the primary event. On the other hand, FKF presents almost the same performance to all multiples that are localized in the same sector of the F-K domain. The two methods can be combined in order to take advantage of their associated potentials. In this situation, DPM is firstly applied, with a focus in the sea bed multiples. Then FKF is applied in order to attenuate the remaining multiples

Dialogização de vozes: o fio construtor do estilo de José Bezerra Gomes no romance A porta e o vento

This research aims to investigate the process of stylistic construction in novelistic prose of Northeastern Brazilian writter José Bezerra Gomes, taking as a corpus his novel called A porta e o vento. The theoretical foundations supporting this study are related to the ideas disseminated by a group of linguistic researchers known as Bakhtin Circle, especially the notions of dialogic language, literary word, concrete utterance, social voices, and sociological style/stylistic. Concerning to methodological guidance, this work is characterized by adopting the interpretive paradigm of socio-historical background, still situated in the great field of Applied Linguistics, an undisciplinary area of research and frontier whose primary focus is concrete and situated language. The analysis allowed me to hear several social voices embodied therein, realizing a variety of dialogs, numerous worldviews in constant struggle, that due to the management and the finish given by the author, eventually create a tone, a unique composition compared to other discourses and current styles in his midst. Ideological clashes are evident: the voice of tradition versus particular character Santos’ voice regarding the institution of marriage; confrontation between antagonistic hinterland pictures - a living hinterland (rich and diverse) as opposed to the stereotypical notion of hinterland (poor and sterile); and the door and the wind as a metaphor of a fighting arena and a hint of poeticization of the language of prose. The main feature of Bezerra’s style in A porta e o vento is related to the aforesaid modes dialogization voices present in the novel. Therefore, one can found veiled polemic, dialogical replicas and veiled dialogues, which are categories already discussed in Bakhtin's theory, but also other new modes dialogization, grounded in the dynamics of living and concrete language

Síntese e caracterização de PSFC (Pr0,5Sr0,5Fe1-xCuxO3-δ, sendo x=0,2 e x=0,4) para aplicação como catodo de células a combustível de óxido sólido

The PSFC (Pr0.5Sr0.5Fe1-xCuxO3-δ) is a new mixed oxide perovskite and has been studied and evaluated the cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs), mainly due to its good compatibility with the electrolyte (CGO) and its high ionic conductivity and electronic in intermediate temperature. In this work, PSFC powders with two different compositions (Pr0,5Sr0,5Fe0,8Cu0,2O3- PSFC5582 and Pr0,5Sr0,5Fe0,6Cu0,4O3-PSFC5564) were synthesized by the citrate method using a new route. The powders obtained were characterized by thermal analysis (Differential Scanning Calorimetry and Thermogravimetry), and the material calcined at 800, 900 and 1000 °C for 5h were analyzed by X-ray diffractometry (XRD), with the Rietveld refinement of the diffraction data and dilatometry. PSFC5582 composite films were obtained by screen printing of powder calcined at 1000 °C. The films were deposited on substrate ceria doped with gadolinia (CGO) and then sintered at 1050 °C for 2h. The electrochemical performance of the electrodes was evaluated by impedance spectroscopy and the interface electrode/electrolyte was observed by scanning electron microscopy (SEM). The specific resistance area (ASR) was 0.44 Ω.cm² at 800 °C, slightly lower than those reported in the literature for cathodes containing cobalt. The thermal expansion coefficients of both the PSFC compositions were obtained and varied between 13 and 15 x 10-6 °C-1 , in a temperature range of 200 to 650 °C, demonstrating the good thermal compatibility of cathodes with Ce0,9Gd0,1O1,95 electrolytes (CET = 12 x 10-6 °C).