Homogeneización de la Guía Docente de “Química del Estado Sólido” en titulaciones de Máster

La asignatura de “Química del Estado Sólido” se imparte actualmente en los Másteres de “Ciencia de Materiales” e “Interuniversitario de Nanociencia y Nanotecnología Molecular”. El programa de esta asignatura en ambos Másteres es ligeramente distinto, ya que en principio así se pensó atendiendo a las particularidades de los objetivos de aprendizaje en cada Máster. Después de la experiencia adquirida tras unos años de funcionamiento de esta asignatura, y dado que la asignatura tiene en ambos Másteres el carácter de “básica”, los autores creen que es posible proceder a una homogeneización curricular con el fin del aprovechamiento de recursos (no sólo humanos, sino también de espacio y tiempo). Esto permite que la asignatura pudiese ser impartida con los mismos objetivos de enseñanza-aprendizaje en ambos Másteres y de manera simultánea. En este trabajos e aborda una propuesta de metodología docente según un enfoque didáctico que cubre las necesidades de formación en ambos Másteres.

Contribuição à gestão ambiental de lodo de esgoto em solos tropicais: determinação da fração de mineralização de compostos nitrogenados.

As quantidades de lodo de esgoto a serem aplicadas a solos agrícolas são determinadas em função de diversos critérios. Um desses critérios considera a quantidade de nitrogênio inorgânico que o resíduo poderá gerar no solo, como nitrato, durante sua mineralização. A prática vigente atualmente no Brasil para definição de dosagens de lodo de esgoto a aplicar em solos agrícolas é determinada pelo CONAMA - Conselho Nacional do Meio Ambiente. Na Resolução 375, publicada em 2006 por esse órgão, recomenda-se a utilização do valor de 20% de disponibilização de N para lodos de esgoto que passem pelo tratamento anaeróbio. Esse valor, entretanto, baseia-se em dados obtidos para solos em climas temperados. Em solos tropicais, já se dispõe de dados de pesquisa, que preconizam índices de disponibilização de N superiores aos da atual legislação. Como o nitrato é altamente lixiviável no perfil do solo, se for gerado em quantidades superiores às absorvidas pelas plantas, torna-se um poluente potencial de águas subsuperficiais. Por essa razão, há necessidade de pesquisas com maior número de solos, dada a grande extensão do território brasileiro, visando-se o estabelecimento e validação de índices locais de disponibilização de N em solos tratados com lodos de esgoto. Porém, ainda não se dispõe de um protocolo específico para a determinação da fração de mineralização de compostos nitrogenados de lodos de esgoto utilizados na agricultura. Visando contribuir para isso, foi estabelecido neste trabalho um protocolo para a determinação da fração de mineralização de compostos de N presentes em lodos de esgoto, quando aplicados em solos agrícolas. Nele, são estabelecidas, passo a passo, as etapas para a estimativa desse índice, utilizando-se as metodologias usuais no Brasil em análises de solo e de resíduos. São apresentados ao final do protocolo resultados experimentais que mostram taxas de mineralização de nitrogênio superiores a estipulada na atual legislação.

Sinterização de Ce1-XEuXO2-(X/2) para aplicação como eletrólito sólido em células a combustível de temperaturas intermediárias

Given the environmental concern over global warming that occurs mainly by emission of CO2 from the combustion of petroleum, coal and natural gas research focused on alternative and clean energy generation has been intensified. Among these, the highlight the solid oxide fuel cell intermediate temperature (IT-SOFC). For application as electrolyte of the devices doped based CeO2 with rare earth ions (TR+ 3) have been quite promising because they have good ionic conductivity and operate at relatively low temperatures (500-800 ° C). In this work, studied the Ce1-xEuxO2-δ (x = 0,1, 0,2 and 0,3), solid solutions synthesized by the polymeric precursor method to be used as solid electrolyte. It was also studied the processing steps of these powders (milling, compaction and two step sintering) in order to obtain dense sintered pellets with reduced grain size and homogeneous microstructure. For this, the powders were characterized by thermal analysis, X-ray diffraction, particle size distribution and scanning electrons microscopy, since the sintered samples were characterized by dilatometry, scanning electrons microscopy, density and grain size measurements. By x-ray diffraction, it was verified the formation of the solid solution for all compositions. Crystallites in the nanometric scale were found for both sintering routes but the two step sintering presented significant reduction in the average grain size

Viabilidade do uso agrícola de resíduo da construção civil e da indústria cerâmica: atributos químicos.

O setor de construção civil enfrenta sérios problemas quanto à disposição de resíduos, uma vez que gera grandes quantidades ao longo do processo de execução das obras ou devido ao desmonte de construções já existentes. A disposição inadequada desses resíduos pode provocar sérios danos ambientais, tais como degradação do solo e recursos hídricos. Uma opção interessante pode ser seu uso agrícola, entretanto existem poucos estudos sobre o tema. Assim, o presente estudo visou caracterizar resíduos da construção civil e avaliar seu efeito sobre alguns atributos do solo. Para tal, foram realizadas análises de pH, teor de macro e micronutrientes e de elementos potencialmente tóxicos. Os resultados indicaram que os resíduos não poderiam ser utilizados como fonte de nutrientes e que também não apresentavam limitações quanto à presença de elementos potencialmente tóxicos. Os altos valores de pH encontrados indicaram potencial dos resíduos em alcalinizar do solo, o que foi confirmado no ensaio em vasos. Também se constatou que os resíduos provocaram aumento da CTC. Assim, concluiu-se que é viável utilizar esses resíduos da construção civil em solos agrícolas, embora mais avaliações ainda devam ser realizadas.

Utilização de resíduo lignocelulósico na obtenção de chapa de madeira aglomerada homogênea e compósito reforçado com fibra de vidro-E

This research is about the use of the coconut´s endocarp (nucifera linn) and the waste of derivatives of wood and furniture as raw material to technological use. In that sense, the lignocellulosic waste is used for manufacture of homogeneous wood sheet agglomerate (LHWS) and lignocellulosic load which take part of a polymeric composite with fiber glass E (GFRP-WC). In the manufacturing of the homogeneous wood sheet agglomerate (LHWS), it was used mamona´s resin as waste s agglutinating element. The plates were taken up in a hydraulic press engine, heated, with temperature control, where they were manufactured for different percentage of waste wood and coconuts nucífera linn. Physical tests were conducted to determine the absorption of water, density, damp grade (in two hours and twenty-four hours), swelling thickness (in two hours and twenty-four hours), and mechanical tests to evaluate the parallel tensile strength (internal stick) and bending and the static (steady) flexural. The physical test´s results indicate that the LHWS can be classified as bonded wood plate of high-density and with highly water resistant. In the mechanical tests it was possible to establish that LHWS presents different characteristics when submitted to uniaxial tensile and to the static (steady) flexural, since brittle and elasticity module had a variation according to the amount of dry endocarp used to manufacture each trace of LHWS. The GFRP-WC was industrially manufactured by a hand-lay-up process where the fiber glass E was used as reinforcement the lignocellulósic´s waste as load. The matrix was made with ortofitalic unsaturated polyester resin. Physical and mechanical tests were performed in presence of saturated humidity and dry. The results indicated good performance of the GFRP-WC, as traction as in flexion in three points. The presence of water influenced the modules obtained in the flexural and tensile but there were no significant alteration in the properties analyzed. As for the fracture, the analysis showed that the effects are more harmful in the presence of damp, under the action of loading tested, but despite this, the fracture was well defined starting in the external parts and spreading to the internal regions when one when it reaches the hybrid load

Concreto celular polimérico: influência na adição de resíduo de poliéster insaturado termofixo

This work addresses the production of lightweight concrete building elements, such as plates, prefabricated slabs for pre-molded and panels of fencing, presenting a singular concrete: the Lightweight Concrete, with special properties such low density and good strength, by means of the joint use of industrial waste of thermosetting unsaturated polyesters and biodegradable foaming agent, named Polymeric Lightweight Concrete. This study covered various features of the materials used in the composition of the Polymeric Lightweight Concrete, using a planning of factorial design 23, aiming at studying of the strength, production, dosage processes, characterization of mechanical properties and microstructural analysis of the transition zone between the light artificial aggregate and the matrix of cement. The results of the mechanical strength tests were analyzed using a computational statistics tool (Statistica software) to understand the behavior and obtain the ideal quantity of each material used in the formula of the Polymeric Lightweight Concrete. The definition of the ideal formula has the purpose of obtaining a material with the lowest possible dry density and resistance to compression in accordance with NBR 12.646/92 (≥ 2.5 MPa after 28 days). In the microstructural characterization by scanning electron microscopy it was observed an influence of the materials in the process of cement hydration, showing good interaction between the wrinkled face of the residue of unsaturated polyesters thermosetting and putty and, consequently, the final strength. The attaining of an ideal formula, given the Brazilian standards, the experimental results obtained in the characterization and comparison of these results with conventional materials, confirmed that the developed Polymeric Lightweight Concrete is suitable for the production of building elements that are advantageous for construction

Adição do resíduo de biomassa da cana-de-açúcar em pastas para cimentação de poços petrolíferos produtores de óleos pesados

The Potiguar basin has large fields of viscous oil where the used method for recovering is based on vapor injection; this operation is carried out by injecting vapor in the oilwell directly, without the protection of a revetment through thermal insulation, what causes its dilation and, consequently, cracks in the cement placed on the annular, and lost of hydraulic insulation; this crack is occasioned by the phenomenon of retrogression of the compressive resistance due to the conversion of the hydrated calcium silicate in phases calcium-rich, caused by the high temperatures in the wells, subjected to thermal recuperation. This work has evaluated the application of composite pastes with addition of residue of biomass of ground sugar-cane bagasse as anti-retrogression mineral admixture for cementation of oil-wells subjected to thermal recuperation. The addition of the mineral residue was carried out considering a relative amount of 10, 20, 30, 40 and 59% in relation to cement mass, trying to improve the microstructure of the paste, still being developed a reference paste only with cement and a paste with addition of 40% of silica flour - renowned material in the oil industry as anti-retrogression additive. Pozzolanic activity of the ash was evaluated through XRD, TG/DTG, as the resistance to compression, and it was also determined the physical and mechanical behavior of the pastes when submitted to cure at low temperatures (22 and 38º C); besides it was evaluated the behavior of the pastes when submitted to two cycles of cure at high temperature (280ºC) and pressure (7 MPa). It was verified that the ash of the sugar-cane biomass presents pozzolanic reaction and has great efficiency in decrease the permeability of the paste by filler effect, as well as that addition of ash in a relative amount of 10, 20 e 30% increases cured compressive resistance at low temperatures. It was also showed that the ash in a relative amount of 40% and 59% has very significant efficiency as anti-retrogression additive, since it prevents the decrease of compressive resistance and forms hydrated calcium silicate type xenotlita and tobermorita which have more resistance and stability in high temperatures

Direito do ambiente : legislação básica

Esta obra reúne a legislação essencial de direito do ambiente.

Estudo da adição do resíduo proveniente da extração de minério de ferro em argilas do Rio Grande do Norte

The mining industry is responsible for the generation of waste from their natural process of extraction. The mining impacts in urban areas are of special importance due to the high urban occupation, which are exacerbated due to the proximity of the mined areas and populated areas. Some solutions to wastedisposal have the potential to significantly reduce the environmental risks and liabilities, but represent higher costs in the stages of deployment and operation. The addition of mining waste as raw material in the development of commercial products reduces the environmental impacts, transforming the waste into a positive element in the generation of employment and income. This thesis studies the incorporation of waste iron ore in two clays, one from the ceramic industry of the City of Natal and the other from the ceramic industry of the Seridó Region, both in the State of Rio Grande do Norte, Brazil. Percentages of iron ore waste of 5%, 10% , 15%, 20%, 25% and 30% were used in the tested ceramic matrix. The two clays and the iron ore waste used as part of this investigation were characterized by X-ray diffraction tests, X-ray fluorescence tests, differential thermal analysis, thermogravimetric analysis and dilatometric analysis. The samples were sintered under temperatures of 850 °C, 950 °C and 1050°C at a heating rate of 5 °C/min with isotherms of two hours. The following tests were performed with the samples: linear shrinkage, water absorption, apparent porosity, apparent density, mass loss in fire and bending resistance in order to obtain their physical and mechanical properties. An amount of 5% of waste iron ore in the matrix clay at a temperature of 850 0C resulted in na increase of about 65% in the tensile strength of the clay samples from the Natal ceramic industry. A linear shrinkage of only 0.12% was observed for the samples, which indicates that the physical properties of the final product were not influenced by the addition of the waste

Aplicação do princípio da igualdade na legislação experimental em Portugal

The experimental legislation follows the development of legislative evaluation practices. Being a legislative technique used not only with the aim of gathering political and social consensus, but also, especially in controversial matters, to provide data and information that will serve as basis for a clarified and justified legislative decision. The characteristic features of the experimental laws are its limited application in time and/or in territory and the prediction, in the law itself, of an evaluation after the experimental period. The application of an experimental law just in a specific geographic area raises constitutional issues because of the implications of the principle of equality. Indeed, the principle of equality, despite admitting some treatment differences between people, commands that these differences have to be legitimate, reasonable and proportional, namely, not arbitrary. Besides the constitutionality problem for the violation of the principle of equality, the experimental laws may also consist of laws restricting fundamental rights and be the cause of the liability of the State, within its legislative function.

Preparação de óxidos mistos de níquel e zinco nanoparticulados a partir de combustíveis alternativos

The field of "Materials Chemistry" has been developing in recent years and there has been a great increase of interest in the synthesis and chemical and physical properties of new inorganic solids. New routes of synthesis and synthesis modified has been developed with the aim not only to optimize the processes in laboratory scale, but also on an industrial scale, and make them acceptable by current environmental legislation. The phenomenology of current solid state chemistry properties coupled with the high temperature superconductivity, ferromagnetism, porosity molecular and colors are evidence affected by the synthesis method, which in turn can influence the technological application of these materials. From this understanding, mixed oxides of nickel and zinc nanoparticulate were synthesized by microwave-assisted combustion route using three specific types of organic fuels employing the weight ratios 1:1/2 and 1:1 of cation metallic/fuel, in order to investigate the influence of such proportions to obtain the solids. The new fuels were chosen to replace, for example, urea or glycine that are the fuels most commonly preferred in this kind of synthesis. The powders without heat treatment were studied by Thermogravimetric analysis (TGA), X-Ray Diffraction (XRD) and then calcined at 900°C. After heat treatment, the samples were characterized by analysis of X Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The modified synthesis route porposed was effective for obtaining powders. Both the alternative fuels chosen as the different weight ratios employed, influenced in the morphology and obtaining oxides

Efeito da adição de feldspato e/ou resíduo de caulin em formulações à base de argila ilítica

The red pottery industry in Piauí state is well developed and stands out at the national context for the technical quality of its products. The floor and wall tile industry, however, is little developed since the state has only one company that produces red clay-based ceramic tiles. This thesis aims at using the predominantly illitic basic mass of the above mentioned industry, with the addition of feldspar and/or kaolin residue in order to obtain products of higher technical quality. Kaolin residue consists basically of kaolinite, muscovite mica and quartz; the feldspar used was potassic. In this experiment, basic mass (MB) was used for experimental control and fifteen formulations codified as follows: F2, F4, F8, F16, F32, FR2, FR4, FR8, FR16, FR32, R2, R4, R8, R16 and R32. All raw materials were dry-milled, classified, formulated and then humidified to 10% water. Thereafter, test samples were produced by unixial pressing process in a rectangular steel matrix (60.0 x 20.0 x 5.0) mm3 at (25 MPa). They were fired at four temperatures: 1080°C, 1120°C, 1160°C, with a heating rate of 10°C/min during up to 10 min in an electric oven, and the last one in an industrial oven with a peak of 1140°C, aim ing to confirm the results found in laboratory and, finally, technological tests were performed: MEA, RL, AA, PA, TRF and PF. The results revealed that the residue under study can be considered a raw material with large potential in the industry of red clay-based ceramic tiles, since the results found both in laboratory and in the industry have shown that the test samples produced from the formulations with up to 4% feldspar and those produced with up to 8% feldspar and residue permitted a reduction in the water absorption rate and an increase in the mechanical resistance while those samples produced with up to 4% residue had an increase in the mechanical resistance when compared to those produced from the basic mass and that the formulation with 2% feldspar and residue presented the best technological properties, lowering the sintering temperature down to 1120°C

Uso de resíduo e de minerais de pegmatito da região do seridó RN e de argilas portuguesas em formulações de grês porcelanato

In the State Rio Grande do Norte, Brazil, the most significant deposits of minerals in the production of granite and pegmatite are Seridó region. Municipalities of Parelhas and Equador are the main responsible for the production of feldspar, quartz, kaolin and granite. The ceramic industries are always in search of competitiveness by investing in new products or improving existing techniques. The stoneware is a type of pottery that stands in the market because it presents technical and aesthetic characteristics superior to other existing products. Characteristics of the raw materials initially obtained with chemical analysis and mineralogical analysis are crucial in getting a product that satisfies the conditions in a manufacturing process and is, in principle, directly related to the firing cycle. This research aimed at developing new formulations for the mass production of ceramic stoneware. The raw materials initially characterized were feldspar, quartz, kaolin and granite. As part of the research was developed at the University of Aveiro, in Portugal, we used two clays used in the production of Portuguese ceramics. The raw material Brazilian and Portuguese and the final product, both in Portugal and Brazil, were analyzed for X-ray fluorescence, X-ray diffraction, granulometric analysis, dilatometric analysis, thermal analysis and analysis of scanning electron microscopy (MEV). The specimens prepared at the University of Aveiro (DECV) were sintered at 10000C and 12000C and the specimens prepared in UFRN were sintered at 10000C, 10500C, 11000C, 11500C, 12000C, 12500C and 13000C, but the best results and demonstrating the presence of the mineral mullite were at temperatures of 12000C, 12500C and 13000C. The results showed that the granite waste used may be considered raw material of excellent quality for use in the ceramic industry and coating floors and more accurately by the industry of stoneware. Physical and mechanical tests conducted on samples of the formulations F01 and F02 developed in UFRN showed a water absorption and mechanical strength suitable for the stoneware

Adição de resíduo cerâmico em pastas geopoliméricas para cimentação de poços de petróleo

The development of activities the of oil and gas sector have promoted the search for suitable materials for cementing oil wells. In the state of the Rio Grande do Norte, the integrity of the cement sheath tends to be impaired during steam injection, a procedure necessary to increase oil recovery in reservoirs with low-viscosity oil. The geopolymer is a material that can be used as alternative cement, since it has been used in the production of fire-resistant components, building structures, and for the control of toxic or radioactive residues. Geopolymers result from condensation polymer alkali aluminosilicates and silicates resulting three-dimensional polymeric structures. They are produced in a manner different from that of Portland cement, which is made an activating solution that is mixed with geopolymer precursor. Among the few works studied allowed us to conclude that the pastes prepared with metakaolin as precursor showed better performance of its properties. Several studies show the addition of waste clay as a means of reducing cost and improving end of the folder properties. On this basis, the goal is to study the influence of the addition of ceramic waste in geopolymer paste. To develop the study of rheology tests were carried out, filtered, thickening time, compressive strength, free water, specific gravity and permeability, according to the American Pretoleum Institute (API). The results for all formulations studied show that the folders have high mechanical strength to a light paste; low filtrate volume, absence of free water, very low permeability, slurry, consistent with a light paste, and thickening time low that can be corrected with the use of a retardant handle. For morphological characterization, microstructural, physical, chemical and thermal tests were carried out by XRD, MEV, DTA, TG, FTIR. In the trial of XRD, it was found that geopolymer is an amorphous material, with a peak of crystalline kaolinite. In tests of TG / DTA, revealed the presence of a significant event, which represents the mass loss related to water, and also observed the reduction of weight loss by increasing the concentration of ceramic waste. In the trial of MEV, we found a uniform matrix without the presence of other phases. In the trial of FT-IR, we observed the presence of the band related to water. From all results it was determined that the optimum concentration range of use is between 2.5 and 5% of waste ceramic

Síntese e caracterização de TaC e óxido misto de tântalo e cobre nanoestruturados a partir do precursor oxálico de tântalo através de reações gás-sólido e sólido-sólido a baixa temperatura

The research and development of nanostructured materials have been growing significantly in the last years. These materials have properties that were significantly modified as compared to conventional materials due to the extremely small dimensions of the crystallites. The tantalum carbide (TaC) is an extremely hard material that has high hardness, high melting point, high chemical stability, good resistance to chemical attack and thermal shock and excellent resistance to oxidation and corrosion. The Compounds of Tantalum impregnated with copper also have excellent dielectric and magnetic properties. Therefore, this study aimed to obtain TaC and mixed tantalum oxide and nanostructured copper from the precursor of tris (oxalate) hydrate ammonium oxitantalato, through gas-solid reaction and solid-solid respectively at low temperature (1000 ° C) and short reaction time. The materials obtained were characterized by X-ray diffraction (XRD), Rietveld refinement, Scanning Electron Microscopy (SEM), Spectroscopy X-Ray Fluorescence (XRF), infrared spectroscopy (IR), thermogravimetric (TG), thermal analysis (DTA) and BET. Through the XRD analyses and the Reitiveld refinement of the TaC with S = 1.1584, we observed the formation of pure tantalum carbide and cubic structure with average crystallite size on the order of 12.5 nanometers. From the synthesis made of mixed oxide of tantalum and copper were formed two distinct phases: CuTa10O26 and Ta2O5, although the latter has been formed in lesser amounts