Modeling Ice Cover on Trails at Grand Canyon National Park

This project used data from the National Park Service, the SRTM data set, and recorded weather conditions to predict snow deposition and snow and ice melt in the Grand Canyon National Park. This model, a simplified version of previous research, shows the location of persistent ice and snow on the Canyon slopes in March.

Interações magnéticas e magnetoresistencia em Co/sub 10/ Cu/sub 90/

Foram investigados os efeitos de tratamentos térmicos nas propriedades estruturais, magnéticas e de magnetotransporte eletrônico de fitas de Co10Cu90 rapidamente resfriadas (“melt-spun”) enfatizando o estudo de possíveis relações entre as interações magnéticas entre grãos, camadas e cristais presentes nestes materiais e a magnetoresistência. A análise combinada da evolução estrutural e da intensidade das interações entre os grãos magnéticos mostra claramente o papel de alguns parâmetros estruturais (tamanho e densidade de partículas, distância entre partículas) e da própria intensidade das interações entre as partículas nas propriedades de transporte eletrônico em presença de um campo magnético.

Processos e componentes mantélicos no norte da Patagônia (Argentina) e relações com a subducção Andina : Evidências petrográficas, geoquímicas e isotópicas em xenólitos ultramáficos mantélicos

Xenólitos ultramáficos, carregados até a superfície da Terra por magmatismo básico alcalino intraplaca, fornecem evidências diretas da natureza e processos envolvidos em modificações do manto litosférico subcontinental, como fusão parcial e metassomatismo. Estes xenólitos têm sido utilizados para identificar processos relacionados a evolução da litosfera continental, estimar a composição original do manto e a escala das heterogeneidades mantélicas. Raramente xenólitos ultramáficos mantélicos são encontrados em ambientes convergentes, no entanto na Patagônia (sul da América do Sul), diversas ocorrências são identificadas em basaltos alcalinos na região de arco e back arc da Cordilheira do Andes. Estes xenólitos oportunizam o estudo dos processos de interação entre a cunha mantélica, a placa oceânica subductada e a astenosfera. Nesta dissertação são apresentados dados petrográficos, mineralógicos, geoquímicos e de isótopos de Sr e O em 22 xenólitos ultramáficos de dois centros vulcânicos Mioceno-Holoceno distintos: Cerro del Mojon (41°06’S-70°13’W) e Estancia Alvarez (40°46’S-68°46’W), localizados na borda NW do Platô de Somuncura, norte de Patagônia (Argentina). A suíte de xenólitos ultramáficos do Cerro del Mojon consiste de espinélio dunitos e harzburgitos mantélicos anidros (Grupo1), espinélio lherzolitos mantélicos anidros (Grupo 2a) e hidratados (Grupo 2b) e espinélio clinopiroxenitos crustais (Grupo 3). Os xenólitos mantélicos do Grupo 1 são depletados (empobrecidos em ETR pesados e HFSE, com baixas razões 87Sr/86Sr em Cpx – 0,7028-0.7037), de alta PT (16-19 kbar, 950-1078 ºC), e têm evidências de metassomatismo críptico (enriquecimento em K, Na ETR leves) atribuído a componentes derivados de sedimentos da placa oceânica subductada, EM 2 (87Sr/86Sr em RT até 0,7126, 87Rb/86Sr até 1,66 e δ18O até +6.78‰). Estes valores anomalamente altos foram obtidos em amostras com bolsões de reação ao redor do espinélio, induzidos pela percolação de fluidos metassomáticos sob altas pressões seguida por descompressão (Sp+fluido→ Cpx+Ol+Sp+melt-andesítico-traquítico). Os xenólitos do Grupo 2 são moderadamente depletados (empobrecidos em HFSE, com baixas a altas razões 87Sr/86Sr em RT e Cpx – 0,7031-0,7045 e δ18O +5-6.2‰), de baixa PT (14-15 kbar, 936-942 ºC), e têm evidências de metassomatismo modal e críptico (enriquecimento em ETR leves, Na, K, Ti, Sr, Hf e anfibólio modal). O metassomatismo críptico parece estar relacionado ao mesmo agente metassomatizante do Grupo 1, mas ocorre em menor intensidade. O metassomatismo modal, no entanto, tem outra origem, podendo ser derivado de fontes mantélicas profundas. A quebra do anfibólio metassomático durante a descompressão e ascensão dos xenólitos até a superfície formou bolsões de reação ao redor do anfibólio (Anf→Cpx+Ol+Sp+melts-basálticos & andesíticos). A suíte de xenólitos ultramáficos de Estancia Alvarez consiste de espinélio harzburgitos anidros mantélicos (Grupo 1a) e espinélio dunitos anidros crustais (Grupo 1b), ambos com veios de serpentina. Os xenólitos mantélicos do Grupo 1a são depletados (empobrecidos em ETR leves e HFSE), de profundidades variadas (P entre 11-18 kbar) e de baixa T (877-961 ºC). Estes xenólitos têm enriquecimento em ETR leves, B, Rb e K, que pode estar relacionado a percolação de fluidos ricos em H2O e LILE gerados pela desidratação de filossilicatos dos sedimentos da placa oceânica (EM 2), como evidenciado por veios de serpentina e altas razões 87Sr/86Sr (0,7046-0,7298), 87Rb/86Sr (0,07-5,63) e valores de δ18O (até +7,88‰).

Conflito socioambiental e o papel dos conselhos gestores: a experiência de São Sebastião, São Paulo

A popularização dos conselhos de políticas públicas setoriais foi fortemente ampliada na década de 1990, decorrente principalmente das estratégias de descentralização da Constituição de 1988. Os municípios brasileiros tiveram as responsabilidades federativas ampliadas, especialmente no que tange a questão ambiental e o desenvolvimento urbano. O trabalho analisa como as correntes ambientais e de planejamento urbano se fundem no desenvolvimento da cidade a partir do estudo de caso sobre o município de São Sebastião, litoral norte de São Paulo tendo atenção especial à gênese do Conselho Municipal de Meio Ambiente e Desenvolvimento Urbano como arena de planejamento, conflito e negociação dos distintos interesses locais. Procurou-se discutir, a luz da teoria democrática, os conceitos de participação e deliberação, como alguns dos elementos essenciais ao funcionamento dos conselhos como instrumento de planejamento público e, dessa forma, apontar os limites que o objeto estudado apresenta na gestão compartilhada das políticas públicas locais.

Influência do teor de calcário no comportamento físico, mecânico e microestrutural de cerâmicas estruturais

There are ores of clay in Piauí State that are used for red structural ceramics, which are naturally contaminated with calcareous vein. This is one thing that impedes its exploration in an adequate way, especially for tile production. The present work aims at verifying the influence of the calcareous contents in the technological structural ceramics area, seeking to determine a maximum permissible calcareous proportion/contents in the ceramic mass using the patterns of the local industry production. For the consecution of this paper, it was characterized the clay and calcareous material by FRX, DRX, TGA and DTA. It was also configurated by extrusion and burnt in the temperatures of 850°C, 900°C, 950°C and 1000°C pieces of the corpus with 0, 5, 10, 15 e 20% of calcareous proportion. After that, it was carried out technological samples of linear retraction, water absortion, apparent porosity, specific apparent mass and mechanic resistance. The results showed the possibility of using calcareous in the ceramic mass and in some cases the technological properties got better

Efeito da adição dos azocorantes DR73 e DB79 nas propriedades do poli(metacrilato de metila)

Currently new polymeric materials have been developed to replace other of traditionally materials classes. The use of dyes allows to expand and to diversify the applications in the polymeric materials development. In this work the behavior and ability of azo dyes Disperse Blue 79 (DB79) and Disperse Red 73 (DR73) on poly(methyl methacrylate) (PMMA) were studied. Two types of mixtures were used in the production of masterbatches: 1) rheometer 2) solution. Processing by extrusion-blow molding of PMMA was carried out in order to evaluate the applications of polymeric films. Thermal analysis were performed by thermogravimetry to evaluate polymer and azo dyes thermal stability. Colorimetric analysis were obtained through monitoring the spectral variations associated with sys/trans/anti azo dyes isomerization process Colorimetric data were treated and evaluated in accordance to the color system RGB and CIEL*ab, by monitoring the color change as function of time. Mechanical properties, characterized by tensile tests, were evaluated and correlated with the presence and content of azo dyes in the samples. Analyses by scanning electronic microscopy (SEM) were performed on the surfaces of samples to check the azo dye dispersion after the mixing process. It was concluded that the production of PMMA/azo dyes is possible and feasible, and the mixtures produced had synergy of properties for use in various applications

Desenvolvimento e caracterização de compósitos poli(tereftalato de etileno) reciclado (PET reciclado) com flocos de vidro.

The growing concern with the solid residues management, observed in the last decade, due to its huge amount and impact, has motivated the search for recycling processes, where these residues can be reprocessed to generate new products, enlarging the cycle of materials and energy which are present. Among the polymeric residues, there is poly (ethylene terephthalate) (PET). PET is used in food packaging, preferably in the bottling of carbonated beverages. The reintegration of post-consumer PET in half can be considered a productive action mitigation of environmental impacts caused by these wastes and it is done through the preparation of several different products at the origin, i.e. food packaging, with recycling rates increasing to each year. This work focused on the development and characterization mechanical, thermal, thermo-mechanical, dynamic mechanical thermal and morphology of the pure recycled PET and recycled PET composites with glass flakes in the weight fraction of 5%, 10% and 20% processed in a single screw extruder, using the following analytical techniques: thermogravimetry (TG), differential scanning calorimetry (DSC), tensile, Izod impact, Rockwell hardness, Vicat softening temperature, melt flow rate, burn rate, dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM). The results of thermal analysis and mechanical properties leading to a positive evaluation, because in the thermograms the addition of glass flakes showed increasing behavior in the initial temperatures of thermal decomposition and melting crystalline, Furthermore was observed growing behavior in the mechanical performance of polymer composites, whose morphological structure was observed by SEM, verifying a good distribution of glass flakes, showing difference orientation in the center and in the surface layer of test body of composites with 10 and 20% of glass flakes. The results of DMTA Tg values of the composites obtained from the peak of tan ä showed little reductions due to poor interfacial adhesion between PET and recycled glass flakes.

Processamento e caracterização da blenda poli (metacrilato de metila) (PMMA) elastomerico e poli (tereftalato de etileno) (PET) pós-consumo

This work studied the immiscible blend of elastomeric poly(methyl methacrylate) (PMMA) with poly(ethylene terephthalate) (PET) bottle grade with and without the use of compatibilizer agent, poly(methyl methacrylate-co-glycidyl methacrylate - co-ethyl acrylate) (MGE). The characterizations of torque rheometry, melt flow index measurement (MFI), measuring the density and the degree of cristallinity by pycnometry, tensile testing, method of work essential fracture (EWF), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed in pure polymer and blends PMMA/PET. The rheological results showed evidence of signs of chemical reaction between the epoxy group MGE with the end groups of the PET chains and also to the elastomeric phase of PMMA. The increase in the concentration of PET reduced torque and adding MGE increased the torque of the blend of PMMA/PET. The results of the MFI also show that elastomeric PMMA showed lower flow and thus higher viscosity than PET. In the results of picnometry observed that increasing the percentage of PET resulted in an increase in density and degree crystallinity of the blends PMMA/PET. The tensile test showed that increasing the percentage of PET resulted in an increase in ultimate strength and elastic modulus and decrease in elongation at break. However, in the phase inversion, where the blend showed evidence of a co-continuous morphology and also, with 30% PET dispersed phase and compatibilized with 5% MGE, there were significant results elongation at break compared to elastomeric PMMA. The applicability of the method of essential work of fracture was shown to be possible for most formulations. And it was observed that with increasing elastomeric PMMA in the formulations of the blends there was an improvement in specific amounts of essential work of fracture (We) and a decrease in the values of specific non-essential work of fracture (βWp)

Efeito da adição do poli(etileno acrilato de metila) (ema) e da fibra de linter de algodão nas propriedades do poli(tereftalato de etileno) reciclado (petrec)

The development of new materials to fill the demand of technological advances is a challenge for many researchers around the world. Strategies such as making blends and composites are promising alternatives to produce materials with different properties from those found in conventional polymers. The objective of this study is to evaluate the effect of adding the copolymer poly(ethylene methyl acrylate) (EMA) and cotton linter fibers (LB) on the properties of recycled poly(ethylene terephthalate) (PETrec) by the development of PETrec/EMA blend and PETrec/EMA/LB blend composite. In order to improve the properties of these materials were added as compatibilizers: Ethylene - methyl acrylate - glycidyl methacrylate terpolymer (EMA-GMA) and maleic anhydride grafted polyethylene (PE-g-MA). The samples were produced using a single screw extruder and then injection molded. The obtained materials were characterized by thermogravimetry (TG), melt flow index (MFI) mensurements, torque rheometry, pycnometry to determinate the density, tensile testing and scanning electron microscopy (SEM). The rheological results showed that the addition of the EMA copolymer increased the viscosity of the blend and LB reduces the viscosity of the blend composite. SEM analysis of the binary blend showed poor interfacial adhesion between the PETrec matrix and the EMA dispersed phase, as well as the blend composite of PETrec/EMA/LB also observed low adhesion with the LB fiber. The tensile tests showed that the increase of EMA percentage decreased the tensile strength and the Young s modulus, also lower EMA percentage samples had increased the elongation at break. The blend composite showed an increase in the tensile strength and in the Young`s modulus, and a decrease in the elongation at break. The blend formulations with lower EMA percentages showed better mechanical properties that agree with the particle size analysis which showed that these formulations presented a smaller diameter of the dispersed phase. The blend composite mechanical tests showed that this material is stronger and stiffer than the blend PETrec/EMA, whose properties have been reduced due to the presence of EMA rubbery phase. The use of EMA-GMA was effective in reducing the particle size of the EMA dispersed phase in the PETrec/EMA blend and PE-g-MA showed evidences of reaction with LB and physical mixture with the EMA

Desenvolvimento de bioblendas poliméricas a partir de gelatina bovina e de tilápia com amido de milho

The natural raw materials acquired special importance beside the mineral raw materials with the need for using alternative sources to oil, because they can be used to produce biopolymers. Gelatin, produced from the denaturation of collagen, and starch, an abundant polysaccharide in various plants, are examples of biopolymers which have several technological applications, especially in films. The objective of this work is to produce polymeric bioblends with gelatin and corn starch using two types of gelatin: commercial bovine gelatin and gelatin produced from mechanically separated flesh of tilapia (Oreochromis niloticus). For the extraction of tilapia gelatin 3 distinct pretreatments, followed by extraction in distilled water under heating were performed. The properties of gelatin extracted were similar to bovine gelatin, and the differences can be explained by the difference in extraction processes and sources. Blends of commercial gelatin and starch were produced in an internal mixer from a Haake torque rheometer, to study the behavior of the gelatin mixture with starch, thus, the same compositions were processed by twin screw extrusion, to define the mixing parameters. Subsequently, the extrusion of blends of tilapia gelatin and corn starch was carried out in the same twin screw extruder. The physico-chemical, rheological and morphological properties of the blends with thermoplastic starch and gelatin were studied. It was found that various properties vary linearly with increasing concentration of the components. The blends produced are immiscible, and among the two gelatins, tilapia gelatin showed a better interfacial adhesion with the corn starch. Regarding the morphology, gelatins formed the dispersed phase in all compositions studied, even in compositions rich in starch. Can be concluded that the procedure for tilapia gelatin extraction is feasible and advantageous, and the increasing in its scale to a reactor of 30 liters is possible, with a satisfactory yield. The bioblends of bovine gelatin/corn starch and tilapia gelatin/corn starch were successfully produced, and the processing conditions were appropriate

Obtenção de pós de tântalo metálico a partir da redução aluminotérmica com ignição a plasma

Metallic tantalum has a high commercial value due to intrinsic properties like excellent ductility, corrosion resistance, high melt and boiling points and good electrical and thermal conductivities. Nowadays, it is mostly used in the manufacture of capacitors, due to excellent dielectric properties of its oxides. In the nature, tantalum occurs in the form of oxide and it is extracted mainly from tantalite-columbite ores. The tantalum is usually produced by the reduction of its oxide, using reductants like carbon, silicon, calcium, magnesium and aluminum. Among these techniques, the aluminothermic reduction has been used as the industrial method to produce niobium, tantalum and their alloys, due to the easy removal of the Al and Al2O3 of the system, easing further refining. In conventional aluminothermic reduction an electrical resistance is used to trigger the reaction. This reaction self-propagates for all the volume of material. In this work, we have developed a novel technique of aluminothermic reduction that uses the hydrogen plasma to trigger the reaction. The results obtained by XRD, SEM and EDS show that is possible to obtain a compound rich in tantalum through this technique of aluminothermic reduction in the plasma reactor

Efeito da velocidade de aquecimento nas propriedades de produtos da cerâmica estrutural

Heating rate is one of the main variables that determine a fire cycle. In industrial processes that use high temperatures, greater fire great can reduce the cost of production and increase productivity. The use of faster and more efficient fire cycles has been little investigated by the structural ceramic industry in Brazil. However, one of the possibilities that aims at modernizing the sector is the use of roller kilns and the inclusion of natural gas as fuel. Thus, the purpose of this study is to investigate the effect of heating rate on the technological properties of structural ceramic products. Clay raw materials from the main ceramic industries in the state of Rio Grande do Norte were characterized. Some of the raw materials characterized were formulated to obtain the best physical and mechanical properties. Next, raw materials and formulations were selected to study the influence of heating rate on the final properties of the ceramic materials. The samples were shaped by pressing and extrusion and submitted to rates of 1 °C/min, 10 °C/min and 20 °C/min, with final temperatures of 850 °C, 950 °C and 1050 °C. Discontinuous cycles with rates of 10 °C/min or 15 °C/min up to 600 °C and a rate of 20 °C/min up to final temperature were also investigated. Technological properties were determined for all the samples and microstructural analysis was carried out under a number of fire conditions. Results indicate that faster and more efficient fire cycles than those currently in practice could be used, limiting only some clay doughs to certain fire conditions. The best results were obtained for the samples submitted to slow cycles up to 600 °C and fast fire sinterization up to 950 °C. This paper presents for the first time the use of a fast fire rate for raw materials and clay formulations and seeks to determine ideal dough and processing conditions for using shorter fire times, thus enabling the use of roller kilns and natural gas in structural ceramic industries

Polimorfismos do gene MSX1 e a fenda labio e/ou palatina não-sindrômica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Changes in physical properties of extruded sour cassava starch and quinoa flour blend snacks

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

Produção de snacks funcionais à base de farinha de soja e polvilho azedo

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