Síntese e impregnação de peneiras moleculares Fe MCM-41 derivada de sílica da casca do arroz

The mesoporous molecular sieves of the MCM-41 and FeMCM-41 type are considered promissory as support for metals used as catalysts in oil-based materials refine processes and as adsorbents for environmental protection proposes. In this work MCM-41 and FeMCM41 were synthesized using rice husk ash - RHA as alternative to the conventional silica source. Hydrothermal synthesis was the method chosen to prepare the materials. Pre-defined synthesis parameters were 100°C for 168 hours, later the precursor was calcinated at 550°C for 2 hours under nitrogen and air flow. The sieves containing different proportions of iron were produced by two routes: introduction of iron salt direct synthesis; and a modification post synthesis consisting in iron salt 1 % and 5% impregnation in the material followed by thermal decomposition. The molecular sieves were characterized by X ray diffraction XRD, Fourier transform infrared spectroscopy FT-IR, X ray fluorescence spectroscopy XFR, scanning electronic microscopy SEM, specific surface area using the BET method, Termogravimetry TG. The kinetic model of Flynn Wall was used with the aim of determining the apparent activation energy of the surfactant remove (CTMABr) in the MCM- 41 porous. The analysis made possible the morphology characterization, identifying the presence of hexagonal structure typical for mesoporous materials, as well as observation of the MCM41 and iron of characteristic bands.

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

Impacto da relação entre médico veterinário e proprietário no tratamento recebido por felinos domésticos

Dissertação de Mestrado Integrado em Medicina Veterinária

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

Produção de fibras de alumina biomórfica a partir do sisal

Sisal is a renewable agricultural resource adapted to the hostile climatic and soil conditions particularly encountered in the semi-arid areas of the state of Rio Grande do Norte. Consequently, sisal has played a strategic role in the economy of the region, as one of few options of income available in the semi-arid. Find new options and adding value to products manufactured from sisal are goals that contribute not only to the scientific and technological development of the Northeastern region, but also to the increase of the family income for people that live in the semi-arid areas where sisal is grown. Lignocellulosic fibers are extracted from sisal and commonly used to produce both handcrafted and industrial goods including ropes, mats and carpets. Alternatively, addedvalue products can be made using sisal to produce alumina fibers (Al2O3) by biotemplating, which consists in the reproduction of the natural fiber-like structure of the starting material. The objective of this study was to evaluate the conditions necessary to convert sisal into alumina fibers by biotemplating. Alumina fibers were obtaining after pretreating sisal fibers and infiltrating them with a Al2Cl6 saturated solution, alumina sol from aluminum isopropoxide or aluminum gas. Heat-treating temperatures varied from 1200 ºC to 1650 °C. The resulting fibers were then characterized by X-ray diffraction and scanning electronic microscopy. Fibers obtained by liquid infiltration revealed conversion only of the surface of the fiber into α-Al2O3, which yielded limited resistance to handling. Gas infiltration resulted in stronger fibers with better reproduction of the inner structure of the original fiber. All converted fibers consisted of 100% α-Al2O3 suggesting a wide range of technological applications especially those that require thermal isolation

Risco psicossocial, sintomas psicopatológicos e competências parentais. Um estudo comparativo entre mães com menores em perigo e mães sem menores em perigo

Dissertação de Mestrado, Psicologia Clínica e da Saúde, Faculdade de Ciências Humanas e Sociais, Universidade do Algarve, 2016

Síntese de nanopartículas de magnetita via decomposição térmica em meio não-aquoso

This work aims at obtaining nanoparticles of iron oxide, the magnetite one (Fe3O4), via synthesis by thermal decomposition through polyol. Thus, two routes were evaluated: a simple decomposition route assisted by reflux and a hydrothermal route both without synthetic air atmosphere using a synthesis temperature of 260ºC. In this work observed the influence of the observe of surfactants which are generally applied in the synthesis of iron oxide nanoparticles decreasing cluster areas. Further, was observed pure magnetite phase without secondary phases generally found in the iron oxide synthesis, a better control of crystallite size, morphology, crystal structure and magnetic behavior. Finally, the introduction of hydroxyl groups on the nanoparticles surface was analyzed besides its employment in the polymer production with OH radicals. The obtained materials were characterized by XRD, DLS, VSM, TEM, TG and DSC analyses. The results for the magnetite obtainment with a particle size greater than 5 nm and smaller than 11 nm, well defined morphology and good magnetic properties with superparamagnetic behavior. The reflux synthesis was more efficient in the deposition of the hydroxyl groups on the nanoparticles surface

Aproveitamento de resíduo de beneficiamento do caulim na produção de porcelanato cerâmico

Nowadays, industries from all sectors have great concerns over the disposition of the residues generated along the productive process. This is not different in the mineral sector, as this generates great volumes of residues. It was verified that the kaolin improvement industry generates great volumes of residue basically constituted of kaolinite, muscovite mica and quartz, which are basic constitution elements to formularisations of ceramics masses to the production of covering of stoneware tiles type. This happens because the methodology applied to the improvement process is still very rudimentary, what causes a very low yield, only ¼ from all the material volume that enters the improvement process, in the end, is marketable. The disposal of this residue, in a general way, causes a very big negative environmental impact, what has justified the researches efforts aiming to find a rational solution to this problem. In this way, the intention of this present work is the utilization of this residue in the manufacture of products to high quality ceramics covering, stoneware tiles in an industrial scale. For this purpose, the influence of the addition of the residue to a standard ceramics mass used by a ceramics sector company, already established in the market, with the intention of verifying the possibility of use of this residue as the mass complementary raw material and even the possible partial or total substitution of one of the components of the mass for the raw material in evidence will be studied. To the accomplishment of this work, the kaolin improvement residue generated by an industry of exploitation and improvement of kaolin, located in the region of Equador-RN, in the levels 1,2,4,8, 16 and 32% will be added to the standard mass already used for the production of stoneware tiles. The raw materials used, kaolin residue and the standard mass, were characterized through DRX, FRX, DTA, TGA and dilatometry. After the sintering of the bodies of test, tests of water absorption, apparent porosity, post burning linear retraction, apparent specific mass and flexural strength (3 point bending) were realized to determinate the technological properties of these materials. The results show the studied residue can be considered raw material of great potential to the industry of floor and ceramics covering of the stoneware tiles type

Determinação da composição nutricional e sais minerais de frutos de juçara (Euterpe Edulis) coletados na região de Curitiba, PR.

2015

El otro lejano : La descripción del extranjero y su entorno natural en la embajada a Tamorlán

Ruy González de Clavijo protagonizó, junto con un equipo de negociadores, la segunda embajada que enviara Enrique III de Castilla a Tamorlán en 1403, cuyo itinerario de ida y vuelta se extiendepor tres años. El autor publica un relato de viaje que compendia una relación de hechos y una descripción minuciosa de la geografía de lastierras transitadas, poblaciones visitadas y las costumbres de los lugareños hasta llegar a Samarcanda, capital del imperio tártaro. El relato de Clavijo brinda unfuerte componente informativo y documental, con la inmediatez y la frescura del testimonio de los viajeros que presencian directamente la mayoría de los acontecimientos por ellos relatados y transmiten sus experiencias concretas. El objetivo de este trabajo es describir las características que los viajeros refieren a lo largo de su periplo, en dos aspectos fundamentales: el aspecto físico de los individuos y la relación que establecen con el espacio natural. En primer término abordaremos la descripción del otro lejano, sus características peculiares, las vestimentas, las costumbres alimentarias, los alojamientos y mobiliario. Seguidamente sintetizaremos los ambientes naturales descriptos por los viajeros: una geografía que se señala como adversa a los desplazamientos prolongados. El autor muestra un interés especial por la transformación de la naturaleza en función de la producción de alimentos y la comercialización de los mismos, así como el tratamiento eficiente de los recursos naturales que facilitan el traslado y la habitabilidad. La hipótesis general sería que la alteridad se percibe en relación a la propia experiencia cultural, y es así como las descripciones de los individuos, las comunidades y el entorno natural se piensan y se traducen en relación con las representaciones del sujeto itinerante. La hipótesis secundaria es que las descripciones se ajustan a las exigencias de la embajada, a las necesidades de concretar las metas de alianza política y económica con el líder tártaro.

El otro lejano : La descripción del extranjero y su entorno natural en la embajada a Tamorlán

Ruy González de Clavijo protagonizó, junto con un equipo de negociadores, la segunda embajada que enviara Enrique III de Castilla a Tamorlán en 1403, cuyo itinerario de ida y vuelta se extiendepor tres años. El autor publica un relato de viaje que compendia una relación de hechos y una descripción minuciosa de la geografía de lastierras transitadas, poblaciones visitadas y las costumbres de los lugareños hasta llegar a Samarcanda, capital del imperio tártaro. El relato de Clavijo brinda unfuerte componente informativo y documental, con la inmediatez y la frescura del testimonio de los viajeros que presencian directamente la mayoría de los acontecimientos por ellos relatados y transmiten sus experiencias concretas. El objetivo de este trabajo es describir las características que los viajeros refieren a lo largo de su periplo, en dos aspectos fundamentales: el aspecto físico de los individuos y la relación que establecen con el espacio natural. En primer término abordaremos la descripción del otro lejano, sus características peculiares, las vestimentas, las costumbres alimentarias, los alojamientos y mobiliario. Seguidamente sintetizaremos los ambientes naturales descriptos por los viajeros: una geografía que se señala como adversa a los desplazamientos prolongados. El autor muestra un interés especial por la transformación de la naturaleza en función de la producción de alimentos y la comercialización de los mismos, así como el tratamiento eficiente de los recursos naturales que facilitan el traslado y la habitabilidad. La hipótesis general sería que la alteridad se percibe en relación a la propia experiencia cultural, y es así como las descripciones de los individuos, las comunidades y el entorno natural se piensan y se traducen en relación con las representaciones del sujeto itinerante. La hipótesis secundaria es que las descripciones se ajustan a las exigencias de la embajada, a las necesidades de concretar las metas de alianza política y económica con el líder tártaro.

El tratado de Lisboa de 1864: la demarcación de la frontera y las identificaciones nacionales

El Tratado de Límites entre España y Portugal, firmado en Lisboa en 1864, constituye un paradigma de los modernos tratados de fronteras interestatales. En este artículo en primer lugar, se aborda el estudio de los trabajos de la Comisión Mixta de Límites que se creó, y de sus relaciones con las poblaciones de la «raya» –nombre que se da localmente a la zona adyacente al límite fronterizo-, para después pasar a analizar las negociaciones diplomáticas y el texto final del Tratado. Para mostrar la relación de la demarcación de la frontera con los procesos de identificación nacionales, se pone en relación con los discursos identitarios sobre los que se asentó, en los que conviene distinguir tres niveles: el discurso «palaciego» de las autoridades centrales y los diplomáticos implicados, el discurso técnico y de progreso de los ingenieros y topógrafos militares de la Comisión, y, finalmente, el discurso de las poblaciones locales.