Membrana de alumina anódica: comportamento da microestrutura e estudo das propriedades ópticas após tratamento térmico

Thin commercial aluminum electrolytic and passed through reactions was obtained with anodic alumina membranes nanopores. These materials have applications in areas recognized electronic, biomedical, chemical and biological weapons, especially in obtaining nanostructures using these membranes as a substrate or template for processing nanowires, nanodots and nanofibers for applications noble. Previous studies showed that the membranes that have undergone heat treatment temperature to 1300° C underwent changes in morphology, crystal structure and optical properties. This aim, this thesis, a study of the heat treatment of porous anodic alumina membranes, in order to obtain and to characterize the behavior changes structures during the crystallization process of the membranes, at temperatures ranging between 300 and 1700° C. It was therefore necessary to mount a system formed by a tubular furnace resistive alumina tube and controlled environment, applying flux with special blend of Ag-87% and 13% N2, in which argon had the role of carrying out the oxygen nitrogen system and induce the closing of the pores during the densification of the membrane. The duration of heat treatment ranged from 60 to 15 minutes, at temperatures from 300 to 1700° C respectively. With the heat treatment occurred: a drastic reduction of porosity, grain growth and increased translucency of the membrane. For the characterization of the membranes were analyzed properties: Physical - thermogravimetric, X-ray diffraction, BET surface area; morphological - SEM, EDS through compositional and, optical absorbance, and transmittance in the UV-VIS, and FTIR. The results using the SEM showed that crystallization has occurred, densification and significant changes in membrane structure, as well as obtaining microtube, the BET analysis showed a decrease in specific surface area of the membranes has to 44.381 m2.g-1 to less than 1.8 m2.g-1 and in the analysis of transmittance and absorbance was found a value of 16.5% in the range of 800 nm, characteristic of the near infrared and FTIR have confirmed the molecular groups of the material. Thus, one can say that the membranes were mixed characteristics and properties which qualify for use in gas filtration system, as well as applications in the range of optical wavelength of the infra-red, and as a substrate of nanomaterials. This requires the continuation and deepening of additional study

Determinação do perfil térmico em amostras de aço AISI M35 imersas em plasma

The heat transfer between plasma and a solid occurs mostly due the radiation and the collision of the particles on the material surface, heating the material from the surface to the bulk. The thermal gradient inside the sample depends of the rate of particles collisions and thermal conductivity of the solid. In order to study that effect, samples of AISI M35 steel, with 9,5 mm X 3,0 mm (diameter X thickness) were quenched in resistive furnace and tempereds in plasma using the plane configuration and hollow cathode, working with pressures of 4 and 10 mbar respectively. Analyzing the samples microstructure and measuring the hardness along the transversal profile, it was possible to associate the tempered temperature evaluating indirectly the thermal profile. This relation was obtained by microstructural analyzes and through the hardness curve x tempered sample temperature in resistive furnace, using temperatures of 500, 550, 600, 650 and 700°C. The microstructural characterization of the samples was obtained by the scanning electron microscopy, optic microscopy and X-ray diffraction. It was verified that all samples treated in plasma presented a superficial layer, denominated affected shelling zone, wich was not present in the samples treated in resistive furnace. Moreover, the samples that presented larger thermal gradient were treated in hollow cathode with pressure of 4 mbar

Estudo térmico dos resíduos gerados da destilação atmosférica das misturas diesel/biodiesel de dendê

The growing world demand for energy supplied by fossil fuels, a major contributor to the emission of pollutants into the atmosphere and causing environmental problems, has been encouraging governments and international organizations to reflect and encourage the use of alternative renewable sources. Among these new possibilities deserves attention biodiesel, fuel cleaner and easy to reproduce. The study of new technologies involving that source is necessary. From this context, the paper aims at analyzing the thermal stability by thermogravimetric analysis, of the waste generated from atmospheric distillation of mixtures with ratios of 5, 10, 15 and 20% palm biodiesel in diesel with and without addition of BHT antioxidant. It was synthesized biodiesel through palm oil, via homogeneous catalysis in the presence of KOH, with and without the use of BHT and subsequently added to the diesel common indoor type (S1800) from a gas station BR. The diesel was already added with 5% biodiesel, and thus the proportions used for these blends were subtracted from the existing ratio in diesel fuel, resulting in the following proportions palm oil biodiesel: 0% (B5), 5% (B10), 10 % (B15) and 15% (B20). From atmospheric distillation analysis, performed in mixtures with and without BHT were collected residue generated by each sample and performed a thermal study from the thermogravimetric analysis at a heating rate of 10 °C.min-1, nitrogen atmosphere and heating to 600 ° C. According to the specifications of Resolution No. 7/2008 for biodiesel, it was found that the material was synthesized in accordance with the specifications. For mixtures, it was noted that the samples were in accordance with the ANP Resolution No. 42/2009. Given the TG / DTG curves of the samples of waste mixtures with and without BHT antioxidant was able to observe that they showed a single stage of thermal decomposition attributed to decomposition of heavy hydrocarbons and esters and other heavier constituents of the waste sample weighed. The thermal behavior of residues from atmospheric distillation of mixtures of diesel / biodiesel is very important to understand how this affects the proper functioning of the engine. A large amount of waste can generate a high content of particulate material, coke formation and carbonaceous deposits in engine valves, compromising their performance

Um modelo matemático baseado em wavelets para análise do método térmico de recuperação de óleo pesado aplicando irradiação eletromagnética

This work proposes a model to investigate the use of a cylindrical antenna used in the thermal method of recovering through electromagnetic radiation of high-viscosity oil. The antenna has a simple geometry, adapted dipole type, and it can be modelled by using Maxwell s equation. The wavelet transforms are used as basis functions and applied in conjunction with the method of moments to obtain the current distribution in the antenna. The electric field, power and temperature distribution are carefully calculated for the analysis of the antenna as electromagnetic heating. The energy performance is analyzed based on thermo-fluid dynamic simulations at field scale, and through the adaptation in the Steam Thermal and Advanced Processes Reservoir Simulator (STARS) by Computer Modelling Group (CMG). The model proposed and the numerical results obtained are stable and presented good agreement with the results reported in the specialized literature

Biodegradação de hidrocarbonetos aromáticos policíclicos: prospecção metagenômica e modelagem computacional 3-D de proteínas

Knowledge of the native prokaryotes in hazardous locations favors the application of biotechnology for bioremediation. Independent strategies for cultivation and metagenomics contribute to further microbiological knowledge, enabling studies with non-cultivable about the "native microbiological status and its potential role in bioremediation, for example, of polycyclic aromatic hydrocarbons (HPA's). Considering the biome mangrove interface fragile and critical bordering the ocean, this study characterizes the native microbiota mangrove potential biodegradability of HPA's using a biomarker for molecular detection and assessment of bacterial diversity by PCR in areas under the influence of oil companies in the Basin Petroleum Geology Potiguar (BPP). We chose PcaF, a metabolic enzyme, to be the molecular biomarker in a PCR-DGGE detection of prokaryotes that degrade HPA s. The PCR-DGGE fingerprints obtained from Paracuru-CE, Fortim-CE and Areia Branca-RN samples revealed the occurrence of fluctuations of microbial communities according to the sampling periods and in response to the impact of oil. In the analysis of microbial communities interference of the oil industry, in Areia Branca-RN and Paracuru-CE was observed that oil is a determinant of microbial diversity. Fortim-CE probably has no direct influence with the oil activity. In order to obtain data for better understanding the transport and biodegradation of HPA's, there were conducted in silico studies with modeling and simulation from obtaining 3-D models of proteins involved in the degradation of phenanthrene in the transport of HPA's and also getting the 3-D model of the enzyme PcaF used as molecular marker in this study. Were realized docking studies with substrates and products to a better understanding about the transport mechanism and catalysis of HPA s

Efeito antiinflamatório de fucana extraída da alga Parda spatoglossum schroederii em modelos experimentais de Peritonite, choque não séptico e colite

Fucans is a name used for sulfated polysaccharides, which is most characteristic structure of the presence of sulfated L-fucose, are found in brown seaweed (Phaeophyceae) and echinoderms (sea urchins and sea cucumbers). These polysaccharides have been reported to possess anticoagulant, antitumor, anti-viral, anti-proliferative and anti-inflammatory activities. Therefore, in the present study was evaluate the effect of the fucan from the brown seaweed Spatoglossum schroederii in models of peritonitis and non-septic shock induced by zymosan, as well as in a murine model of colitis induces by DSS. So, the mice treatment by intravenous route with the fucan was able to reduce the exudate formation and the cell migration in the model of acute peritonitis induced by zymosan during the kinetic of 6, 24 and 48 hours. Similarly, in the model of non-septic shock induced by zymosan the fucan demonstrated a protector effect to inhibited the cellular migration to the peritoneo, to decrease the levels of IL-6 in the serum and in the peritoneal exudate, to attenuate the lose of weight in the mice; beside to reduce the serum levels of hepatic transaminases and as well as the liver injury. In the model of murine colitis, the treatment with the fucan reduced the lose of weight of the animals, decreased the levels of IL-17 and IFN- produced in the gut and decrease the intestinal lesion induced by DSS. In conclusion, the fucan used in this study presented a significant protector effect in the murine models of inflammation

Proteínas SAG1, SAG2, SAG3 de toxoplasma gondii como perspectivas para o desenvolvimento de protótipo vacinal contra a toxoplasmose

Toxoplasmosis is a zoonosis of worldwide distribution caused by the protozoan Toxoplasma gondii, triggering dangerous complications in immunocompromised patients and pregnant women, as well as having great economic impact for the livestock. So far the control of toxoplasmosis is made primarily by chemotherapy. However, most drugs used routinely have some limitations. In order to control this disease, several research groups, including ours, has been working to develop a medical-veterinary vaccine based on parasite antigens, vectors and protocols of immunization. In this study were implemented and standardized methodologies for amplification and cloning of recombinant immunogens in the system for the development of a prototype vaccine, based on the surface antigens of T. gondii and recombinant adenovirus encoding these antigens. Genes encoding BAG1, GRA2 and SAG1 proteins were amplified. We established a strategy for cloning SAG1, SAG2, SAG3 and TgAMA1- genes in recombinant system. The genes encoding SAG1 and SAG2 were cloned and their sequences showed high similarity with sequences from GenBank. The virtual translation of these proteins showed polymorphisms in the amino acid sequence, which can be correlated with levels of antigenicity. Simultaneously, the adenovirus encoding the SAGs (HAdSAGs) were expanded, purificated and characterizated. Immunization of C57bl/6 mice, using viral supernatant was not enought to elicit immune responses at high levels, being required HAdSAGs titration for future immunizations. Therefore, this study allowed the cloning of the two genes important for the development of a prototype vaccine. Besides, implementations methodologies that permit advancements in the development of a vaccine against toxoplasmosis using adenovirus to express proteins of the parasite

Extração, caracterização e atividades biológicas de proteínas da espécie cnidoscolus urens (L.) Arthur

The extraction, chemical and structural characterization of a wide variety of compounds derived from plants has been a major source of bioactive molecules. Several proteases have been isolated in the plant kingdom, with numerous pharmacological and biotechnological applications. Among the proteases isolated from plants, are the fibrinogenolytic, with relevant application in the treatment of disorders in the coagulation cascade, in addition to potential use as a tool in clinical laboratories. In this study, in addition to evaluating the effects of the protein extract of Cnidoscolus urens (L.) Arthur (Euphorbiaceae) in the coagulation cascade also investigates the presence of antimicrobial activity and characterizes the proteolytic activity detected in this extract, aiming to determine their potential pharmacological and biotechnological application. In this way, crude protein extracts obtained from the leaves of C. urens in Tris-HCl 0.05M, NaCl 0.15M, pH 7.5, were precipitated in different concentrations of acetone, and assessed for the presence of proteolytic activity in azocaseína and fibrinogen. The most active fraction (F1.0) in these tests was chosen for assessment of biological activity and biochemical characterization. The Aα chain and Bβ of fibrinogen were completely cleaved at a concentration of 0.18 μg/μL of protein fraction in 4 minutes. Fibrinogenolytic activity presented total inhibition in the presence of E-64 and partial in the presence of EDTA. The fraction demonstrated coagulant activity in plasm and reduced the APTT, demonstrating acting on the factors coagulation of the intrinsic pathway and common, not exerting effects on the PT. Fibrinolytic activity on plasma clot was detected only in SDS-PAGE in high concentrations of fraction, and there were no defibrinating. Although several proteases isolated from plants and venomous animals are classically toxic, the fraction F1.0 of C. urens not expressed hemorrhagic nor hemolytic activities. Fraction F1.0 also showed no antimicrobial activity. In proteolytic activity on the azocasein, the optimal pH was 5.0 and optimum temperature of 60ºC. The enzyme activity has been shown to be sensitive to the presence of salts tested, with inhibition for all compounds. The surfactant triton did not influence the enzyme activity, but the tween-20 and SDS inhibited the activity. In the presence of reducing agents increase in enzyme activity occurred, a typical feature of enzymes belonging to the class of cysteine proteases. Several bands with proteolytic activity were detected in zymogram, in the region of high-molecular-weight, which were inhibited by E-64. In this study, we found that C. urens presents in its constitution cysteine proteases with fibrinogenolytic and procoagulant activity, which may be isolated, with potential application in treatment of bleeding disorders, thrombolytic and clinical laboratory

Estudo do perfil térmico de fornos do tipo "caipira" utilizados pelo setor de cerâmica vermelha em parelhas na região Seridó-RN

The present study aimed to characterize the thermal profile of wood fired oven used by the red ceramic industry in Parelhas, in the Seridó region/RN, aiming to propose structural interventions that can contribute to increasing productivity and product quality, optimize wood consumption and mitigate existing losses during the burning process. The study was conducted at Cerâmica Esperança in the city of Parelhas -RN, Brazil, during the period from August 2012 to September 2013. Four treatments were performed with three replicates, ie, with, a total of 12 experimental units (burnings). In the first stage 4 treatments were performed with three replicates, totaling 12 experimental units (firings). In the second stage 2 treatments were performed with three replications, totaling 6 experimental units (firings). The physical characteristics of the wood were analyzed using standard NBR 11941 and NBR 7190 for basic density and moisture, respectively. The clay was used as a reference parameter for distinguishing treatments. For both the analysis and characterization was carried out using techniques of fluorescence X (XRF) rays, X-ray diffraction (XRD) analysis, particle size analysis (FA). In the first and second stages were monitored: the time during the firing process, the amount of wood used at each firing, the number of parts enfornadas for subsequent determination of the percentages of losses, but also product quality. To characterize the thermal profile of the oven, we measured the temperature at 15 points scored in the surface charge put into the oven. Measurements were taken every 30 minutes from preheat until the end of burning, using a pyrometer laser sight sighting from preheating until the end of burning. In the second step 12 metal cylinders distributed on the oven walls, and the cylinder end walls 8 of the furnace 2 and rollers on each side walls are installed equidistant to 17 cm from the soil and the surface 30 of the wall are installed. The cylinders distributed on the front were placed 50 cm above the furnace, and the base of the oven 20 cm distant from the ground. 10 also thermocouples were installed, and five thermocouples distributed 1.77 cm above the combustion chambers, and one thermocouple on each side, and three thermocouples in front of the oven. We carried out the measurements of the temperatures every 1 hour during the burning two hours in cooling the cylinders with a pyrometer and thermocouples for dattaloger. These were fixed with depth of 30 cm from the wall. After statistical analysis it was found that: the thermal profile of the furnace surface and at different heights was heterogeneous; and the ranges of density and moisture content of wood are within recommended for use as an energy source standards. We conclude that even at low temperatures reached during firing there was a significant production of good quality products, this is due to high concentrations of iron oxide and potassium oxide found in clay, which lowers the melting point of the piece. The average burn time for each step varied 650-2100 minutes wood consumption was on average 20 m3, product quality was on average 16% of first quality, 70% second, third and 5% to 10% loss . The distance between the wire and the surface of the oven was a significant parameter for all treatments, but with different variations, meaning that the wire should not be so generic and unique form, used as a criterion for completion of the burn process. The central part of the furnace was the area that reached higher temperature, and in a unified manner, with the highest concentration of top quality products. The ideal temperature curve, which provided the highest quality of ceramic products was achieved in the central part of the furnace

O choque das culturas da ordem

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Conversor CC/CA de alta freqüência baseado em inversores ressonantes com comutação seqüencial para excitação de uma tocha indutiva a plasma térmico

This work describes the study, the analysis, the project methodology and the constructive details of a high frequency DC/AC resonant series converter using sequential commutation techniques for the excitation of an inductive coupled thermal plasma torch. The aim of this thesis is to show the new modulation technique potentialities and to present a technological option for the high-frequency electronic power converters development. The resonant converter operates at 50 kW output power under a 400 kHz frequency and it is constituted by inverter cells using ultra-fast IGBT devices. In order to minimize the turn-off losses, the inverter cells operates in a ZVS mode referred by a modified PLL loop that maintains this condition stable, despite the load variations. The sequential pulse gating command strategy used it allows to operate the IGBT devices on its maximum power limits using the derating and destressing current scheme, as well as it propitiates a frequency multiplication of the inverters set. The output converter is connected to a series resonant circuit constituted by the applicator ICTP torch, a compensation capacitor and an impedance matching RF transformer. At the final, are presented the experimental results and the many tests achieved in laboratory as form to validate the proposed new technique

Aplicação de técnicas de aprendizado de máquina no reconhecimento de classes estruturais de proteínas

Nowadays, classifying proteins in structural classes, which concerns the inference of patterns in their 3D conformation, is one of the most important open problems in Molecular Biology. The main reason for this is that the function of a protein is intrinsically related to its spatial conformation. However, such conformations are very difficult to be obtained experimentally in laboratory. Thus, this problem has drawn the attention of many researchers in Bioinformatics. Considering the great difference between the number of protein sequences already known and the number of three-dimensional structures determined experimentally, the demand of automated techniques for structural classification of proteins is very high. In this context, computational tools, especially Machine Learning (ML) techniques, have become essential to deal with this problem. In this work, ML techniques are used in the recognition of protein structural classes: Decision Trees, k-Nearest Neighbor, Naive Bayes, Support Vector Machine and Neural Networks. These methods have been chosen because they represent different paradigms of learning and have been widely used in the Bioinfornmatics literature. Aiming to obtain an improvment in the performance of these techniques (individual classifiers), homogeneous (Bagging and Boosting) and heterogeneous (Voting, Stacking and StackingC) multiclassification systems are used. Moreover, since the protein database used in this work presents the problem of imbalanced classes, artificial techniques for class balance (Undersampling Random, Tomek Links, CNN, NCL and OSS) are used to minimize such a problem. In order to evaluate the ML methods, a cross-validation procedure is applied, where the accuracy of the classifiers is measured using the mean of classification error rate, on independent test sets. These means are compared, two by two, by the hypothesis test aiming to evaluate if there is, statistically, a significant difference between them. With respect to the results obtained with the individual classifiers, Support Vector Machine presented the best accuracy. In terms of the multi-classification systems (homogeneous and heterogeneous), they showed, in general, a superior or similar performance when compared to the one achieved by the individual classifiers used - especially Boosting with Decision Tree and the StackingC with Linear Regression as meta classifier. The Voting method, despite of its simplicity, has shown to be adequate for solving the problem presented in this work. The techniques for class balance, on the other hand, have not produced a significant improvement in the global classification error. Nevertheless, the use of such techniques did improve the classification error for the minority class. In this context, the NCL technique has shown to be more appropriated

Fibras de sisal (Agave sisalana) como isolante térmico de tubulações

In the last decades there was a significant increasing of the numbers of researchers that joint efforts to find alternatives to improve the development of low environmental impact technology. Materials based on renewable resources have enormous potentials of applications and are seen as alternatives for the sustainable development. Within other parameters, the sustainability depends on the energetic efficiency, which depends on the thermal insulation. Alternative materials, including vegetal fibers, can be applied to thermal insulation, where its first goal is to minimize the loss of energy. In the present research, it was experimentally analyzed the thermal behavior of fiber blankets of sisal (Agave sisalana) with and without surface treatment with oxide hidroxide (NaOH). Blankets with two densities (1100/1200 and 1300/1400 g/m2) were submitted to three rates of heat transfer (22.5 W, 40 W and 62.5 W). The analysis of the results allowed comparing the blankets treated and untreated in each situation. Others experiments were carried out to obtain the thermal conductivity (k), heat capacity (C) and the thermal diffusivity (α) of the blankets. Thermo gravimetric analyses were made to the verification of the thermal stability. Based on the results it was possible to relate qualitatively the effect of the heat transfer through the sisal blankets subjected to three heat transfer rates, corresponding to three temperature values (77 °C, 112 °C e 155 °C). To the first and second values of temperature it was verified a considerable reduction on the rate of heat transfer; nevertheless, to the third value of temperature, the surface of the blankets (treated and untreated) in contact with the heated surface of the tube were carbonized. It was also verified, through the analyses of the results of the measurements of k, C e α, that the blankets treated and untreated have values near to the conventional isolating materials, as glass wool and rock wool. It could be concluded that is technically possible the use of sisal blankets as constitutive material of thermal isolation systems in applications where the temperature do not reach values greater than 112 ºC

Análise do desempenho térmico de sistema constutivo de concreto com EPS como agregado graúdo

In the last decades there was a concentrate effort of researchers in the search for options to the problem of the continuity of city development and environmental preservation. The recycling and reuse of materials in industry have been considerate as the best option to sustainable development. One of the relevant aspects in this case refers to the rational use of electrical energy. At this point, the role of engineering is to conceive new processes and materials, with the objective of reducing energy consumption and maintaining, at the same time the benefits of the technology. In this context, the objective of the present research is to analyze quantitatively the thermal behavior of walls constructed with concrete blocks which composition aggregates the expanded polystyrene (EPS) reused in the shape of flakes and in the shape of a board, resulting in a “light concrete”. Experiments were conducted, systematically, with a wall (considerate as a standard) constructed with blocks of ordinary concrete; two walls constructed with blocks of light concrete, distinct by the proportion of EPS/sand; a wall of ceramic bricks (“eight holes” type) and a wall with ordinary blocks of cement, in a way to obtain a comparative analysis of the thermal behavior of the systems. Others tests conducted with the blocks were: stress analysis and thermal properties analysis (ρ, cp e k). Based on the results, it was possible to establish quantitative relationship between the concentration (density) of EPS in the constructive elements and the decreasing of the heat transfer rate, that also changes the others thermal properties of the material, as was proved. It was observed that the walls of light concrete presents better thermal behavior compared with the other two constructive systems world wide used. Based in the results of the investigation, there was shown the viability of the use of EPS as aggregate (raw material) in the composition of the concrete, with the objective of the fabrication of blocks to non-structural masonry that works as a thermal insulation in buildings. A direct consequence of this result is the possibility of reduction of the consume of the electrical energy used to climatization of buildings. Other aspect of the investigation that must be pointed was the reuse of the EPS as a raw material to civil construction, with a clear benefit to reducing of environmental problems

Estudo térmico e de materiais de um compósito à base de gesso e EPS para construção de casas populares

A housing unit was built to study the thermal performance, and of material using a composite made of gypsum and EPS ground. We used two techniques of construction, using blocks, and filling on the spot. Two compositions of the composite were studied. The blocks were fixed using conventional mortar. In the technical of filling on the spot were used PET bottles up inside the walls to provide mechanical and thermal resistance. Compression tests were realized according to the ABNT standard of sealing bricks. It is going to be shown an analysis of the thermal comfort through the use of thermocouples placed on the walls of the building, internally and externally. The manufacturing viability of houses, using recyclable materials, through the use of composite materials proposed will be demonstrated. The constructive aspects showing the advantages and disadvantages of the technique used also will be broached. The block used presents structural functions and thermal insulating, is low cost and represents an alternative to the use of EPS and PET bottles which are materials that end up occupying much space in the landfills, giving than an ecologically correct use. The results of thermal analysis shows the thermal comfort provided by the composite by the obtainment of a difference between the internal and external surfaces of the walls more exposed to the sun around 7º C. The average temperature of the air inside the building, around 28.0 º C was below the zone of thermal comfort recommended for countries with hot weather