Aplicação da técnica eletroanalítica de pulso diferencial usando o eletrodo de carbono vítreo modificado com cisteína para monitorar a degradação eletroquímica de ácido oxálico

In this paper, the technique of differential pulse voltammetry (DPV) has been studied for monitoring the concentration of oxalic acid (OA) during their electrochemical oxidation (EO) in acidic medium using platinum anode supported on titanium (Ti / Pt). The DPV was standardized and optimized using a glassy carbon electrode modified with cysteine. The modification with cysteine was developed electrochemically, forming a polymeric film on the surface of the glassy carbon electrode. The formation of the polymer film was confirmed by analysis of scanning electron microscope and atomic force microscope, confirming the modification of the electrode. The electrochemical degradation was developed using different current densities 10, 20 30 and 40 mA cm -2 electrode with Ti / Pt observing the degradation of oxalic acid, and monitored using the method of KMnO4 titration. However, the analyzes with DPV showed the same behavior elimination of oxalic acid titration. Compared with the titration method classical observed and DPV could be a good fit, confidence limits of detection and confirming the applicability of the technique electroanalytical for monitoring the degradation of oxalic acid

Caracterização e aplicação de vermicultura natural e quimicamente modificada na adsorção de azul de metileno

Chemical modification of clays has been extremely studied in the search for improvements of their properties for use in various areas, such as in combating pollution by industrial effluents and dyes. In this work, the vermiculite was chemically modified in two ways, characterized and evaluated the adsorption of methylene blue dye. First was changed with the addition of a surfactant (hexadecyltrimethylammonium bromide, BHTA) making it an organophilic clay and then by adding an acid (HCl) by acid activation. Some analyzes were performed as X-ray fluorescence (FRX), X-ray diffraction (DRX), adsorption isotherms of methylene blue dye, infrared (FTIR) , scanning electron microscopy (SEM), thermal gravimetric analysis and spectroscopy energy dispersive (EDS). Analysis by FRX of natural vermiculite indicates that addition of silicon and aluminum, clay presents in its structure the magnesium, calcium and potassium with 16 % organic matter cations. The DRX analyzes indicated that the organic vermiculite was an insertion of the surfactant in the space between the lamellae, vermiculite and acid partial destruction of the structure with loss of crystallinity. The adsorption isotherms of methylene blue showed that there was a significant improvement in the removal of dye to the vermiculite with the addition of cationic surfactant hexadecyltrimethylammonium bromide and treatment with acid using HCl 2 mol/L. In acid vermiculites subsequently treated with surfactant, the adsorption capacity increased with respect to natural vermiculite, however was much lower compared vermiculite modified with acid and surfactant separately. Only the acidic vermiculite treated with surfactant adjusted to the Langmuir model. As in the infrared spectrometry proved the characteristics of natural vermiculite. In the organic vermiculite was observed the appearance of characteristic bands of CH3, CH2, and (CH3)4N. Already on acid vermiculite, it was realized a partial destruction with decreasing intensity of the characteristic band of vermiculite that is between 1074 and 952 cm-1. In the SEM analysis, it was observed that there was partial destruction to the acid treatment and a cluster is noted between the blades caused by the presence of the surfactant. The TG shows that the higher mass loss occurs at the beginning of the heating caused by the elimination of water absorbed on the surface between layers. In the organic vermiculite also observed a loss of mass between 150 and 300 °C caused decomposition of the alkylammonium molecules (surfactants)

Melhorando a estimação de pose com o RANSAC preemptivo generalizado e múltiplos geradores de hipóteses

The camera motion estimation represents one of the fundamental problems in Computer Vision and it may be solved by several methods. Preemptive RANSAC is one of them, which in spite of its robustness and speed possesses a lack of flexibility related to the requirements of applications and hardware platforms using it. In this work, we propose an improvement to the structure of Preemptive RANSAC in order to overcome such limitations and make it feasible to execute on devices with heterogeneous resources (specially low budget systems) under tighter time and accuracy constraints. We derived a function called BRUMA from Preemptive RANSAC, which is able to generalize several preemption schemes, allowing previously fixed parameters (block size and elimination factor) to be changed according the applications constraints. We also propose the Generalized Preemptive RANSAC method, which allows to determine the maximum number of hipotheses an algorithm may generate. The experiments performed show the superiority of our method in the expected scenarios. Moreover, additional experiments show that the multimethod hypotheses generation achieved more robust results related to the variability in the set of evaluated motion directions

Diretrizes para conservação da espécie Mimosa Caesalpiniifolia Benth., Macaíba-RN

About 40% of the earth is occupied by tropical and subtropical forests, including 42% of dry forests, where there is Caatinga Bioma, contemplating tree forests and shrubs, with xerophytic characteristics. Study and conservations of Caatinga biologic diversity is one of the greatest challenges of Brazilian science because those are, proportionally, the less studied among natural areas, with most of the scientific effort centered in very few points around the main cities in the area and also because it is the less protected natural Brazilian area. The environmental degradation is constantly increasing and has its rhythm accelerated by the men appropriation to meet or not their own needs. Therefore, species conservation should be based in three principles: the use of natural resources by present generation, waste prevention and use of the natural resources to benefit the majority of the citizens. Among the strategies to species conservation, we can mention the ex situ conservation , in which the conservation of genetic resources may be realized outside of the natural environment in which the species occur, and in situ conservation , or, in other words, in the places where the species occur. In ex situ conservation, the germplasm collections are maintained in the field and/or in laboratories (conservation chambers), and this mainly conserves intraspecific diversity (genetic variance), the ex situ collections are continuously enriched by collection activities, introduction and germplasm interchange; the in situ conservation preserving ecosystems and habitats, maintaining and recovering native population of species of interest. So, the objective of this paper is the search for strategies to the conservation of Mimosa caesalpiniifolia B. (sabiá) using instruments of environmental perception and plant biotechnology, as mechanisms of in situ and ex situ conservation. To environmental perception, were realized open, semi-structured and qualitative interviews. The questions included socioeconomic data and knowledge of Sabiá specie. To plant biotechnology, Sabiá seed collection were realized in different location to formation of a germplasm bank. The specie micropropagation was made from nodal segment of plants from the matrizeiro. About the knowledge of rural populations and the use of Sabiá plant, some preferences occurred from speeches that the plant possesses a firm wood, not attacked by termites, legalized for exploration by the Brazilian environmental organ (IBAMA), and is a native specie. This research found the rural population has knowledge about Sabiá specie and the natural resources are exhausting. The proposal that the rural community brought was the donation of the Sabiá specie seeding initiating on the rain season, in which the seeding would be plated between the lots, in individual plantations. To the formation of a matrix bank, plant biothecnology brought answers favorable to Sabiá specie seeding, with the formation of multiple shoots

Síntese e caracterização de pós Ba(x)Sr(1-x)Co0,8Fe0,2O3- através do método de coprecipitação via oxalato

Ceramic powders based on oxides of perovskite-type structure is of fundamental interest nowadays, since they have important ionic-electronic conductivity in the use of materials with technological applications such as gas sensors, oxygen permeation membranes, catalysts and electrolytes for solid oxide fuel cells (SOFC). The main objective of the project is to develop nanostructured ceramic compounds quaternary-based oxide Barium (Br), Strontium (Sr), Cobalt (Co) and Iron (Fe). In this project were synthesized compounds BaxSr(1-x)Co0, 8Fe0,2O3- (x = 0.2, 0.5 and 0.8) through the oxalate co-precipitation method. The synthesized powders were characterized by thermogravimetric analysis and differential thermal analysis (TGADTA), X-ray diffraction (XRD) with the Rietveld refinement using the software MAUD and scanning electron microscopy (SEM). The results showed that the synthesis technique used was suitable for production of nanostructured ceramic solid solutions. The powders obtained had a crystalline phase with perovskite-type structure. The TGA-DTA results showed that the homogeneous phase of interest was obtained temperature above 1034°C. It was also observed that the heating rate of the calcination process did not affect the elimination of impurities present in the ceramic powder. The variation in the addition of barium dopant promoted changes in the average crystallite size in the nanometer range, the composition being BSCF(5582) obtained the lowest value (179.0nm). The results obtained by oxalate co-precipitation method were compared with those synthesis methods in solid state and EDTA-citrate method

Verificação formal automatizada para sistemas de raciocínio procedural (PRS) utilizando redes de petri coloridas (RPC)

Este trabalho apresenta uma técnica de verificação formal de Sistemas de Raciocínio Procedural, PRS (Procedural Reasoning System), uma linguagem de programação que utiliza a abordagem do raciocínio procedural. Esta técnica baseia-se na utilização de regras de conversão entre programas PRS e Redes de Petri Coloridas (RPC). Para isso, são apresentadas regras de conversão de um sub-conjunto bem expressivo da maioria da sintaxe utilizada na linguagem PRS para RPC. A fim de proceder fia verificação formal do programa PRS especificado, uma vez que se disponha da rede de Petri equivalente ao programa PRS, utilizamos o formalismo das RPCs (verificação das propriedades estruturais e comportamentais) para analisarmos formalmente o programa PRS equivalente. Utilizamos uma ferramenta computacional disponível para desenhar, simular e analisar as redes de Petri coloridas geradas. Uma vez que disponhamos das regras de conversão PRS-RPC, podemos ser levados a querer fazer esta conversão de maneira estritamente manual. No entanto, a probabilidade de introdução de erros na conversão é grande, fazendo com que o esforço necessário para garantirmos a corretude da conversão manual seja da mesma ordem de grandeza que a eliminação de eventuais erros diretamente no programa PRS original. Assim, a conversão automatizada é de suma importância para evitar que a conversão manual nos leve a erros indesejáveis, podendo invalidar todo o processo de conversão. A principal contribuição deste trabalho de pesquisa diz respeito ao desenvolvimento de uma técnica de verificação formal automatizada que consiste basicamente em duas etapas distintas, embora inter-relacionadas. A primeira fase diz respeito fias regras de conversão de PRS para RPC. A segunda fase é concernente ao desenvolvimento de um conversor para fazer a transformação de maneira automatizada dos programas PRS para as RPCs. A conversão automática é possível, porque todas as regras de conversão apresentadas seguem leis de formação genéricas, passíveis de serem incluídas em algoritmos

O circuito espacial de produção e os círculos de cooperação da soja no Maranhão no período técnico-científico informacional

The study in screen it has as objective the understanding of the space circuit of production and the circles of cooperation of the soy that if develop in the Maranhão in the technician-scientific-informational period. Characterized for the material and incorporeal flows if they develop in the Maranhão, from the moment where it had a process of integration of the maranhense territory while peripheral space of the capitalist dynamics, that if gave through the politics of regional integration created by the State, but when it had a process of selective modernization, also partial and conservative of the agriculture, that made possible the significant increase of the production and reproduction of the capital. The study sample that with the advent of the soy, had a concentration of the production techniques, mainly in the agricultural region of Balsas, due to bigger it offers of lands, time of implantation of the culture, technique accumulated in the production, whereas in the agricultural region of Chapadinha, these indices still are without representation. Moreover, the intensification of the agricultural credit, the agrarian politics and tax incentives are elements that have propitiated increase of the production of the soy. The development of the space circuit and circles of cooperation of the soy, a side, create new forces politics in the Maranhão that can result in the creation of a new state, the other, are responsible, for the elimination of part of the subsistence agriculture, producing social problems as, agrarian concentration and unemployment. The study it still evidences the appropriation of the place for a small number of companies that has generated, beyond an intense concentration of income, an alienation of the territory, in view of that this is used for a strange purpose to the place and the yearning of the population does not stop