Estudo da síntese e propriedade magnética de ferritas de manganês/cobalto dopadas com níquel

For the chemical method of synthesis of co-precipitation were produced ferrite powders manganese-cobalt equal stoichiometric formula Mn (1-x) Co (x) Fe2O4, for 0 < x < 1, first reagent element using as the hydroxide ammonium and second time using sodium hydroxide. The obtained powders were calcined at 400 ° C, 650 ° C, 900 ° C and 1150 ° C in a conventional oven type furnace with an air atmosphere for a period of 240 minutes. Other samples were calcined at a temperature of 900 ° C in a controlled atmosphere of argon, to evaluate the possible influence of the atmosphere on the final results the structure and morphology. The samples were also calcined in a microwave oven at 400 ° C and 650 ° C for a period of 45 minutes possible to evaluate the performance of this type of heat treatment furnace. It was successfully tested the ability of this group include isomorphic ferrite with the inclusion of nickel cations in order to evaluate the occurrence of disorder in the crystalline structures and their changes in magnetic characteristics.To identify the structural, morphological, chemical composition and proportions, as well as their magnetic characteristics were performed characterization tests of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDX), thermogravimetric (TG), vibrating sample magnetometry (MAV) and Mössbauer spectroscopy. These tests revealed the occurrence of distortion in the crystal lattice, changes in magnetic response, occurrence of nanosized particles and superparamagnetism

Estudo de reatores eletroquímicos para remoção de Cu2+ , Zn2+, Fenol e BTEX em água produzida

The production of water has become one of the most important wastes in the petroleum industry, specifically in the up stream segment. The treatment of this kind of effluents is complex and normally requires high costs. In this context, the electrochemical treatment emerges as an alternative methodology for treating the wastewaters. It employs electrochemical reactions to increase the capability and efficiency of the traditional chemical treatments for associated produced water. The use of electrochemical reactors can be effective with small changes in traditional treatments, generally not representing a significant additional surface area for new equipments (due to the high cost of square meter on offshore platforms) and also it can use almost the same equipments, in continuous or batch flow, without others high costs investments. Electrochemical treatment causes low environmental impact, because the process uses electrons as reagent and generates small amount of wastes. In this work, it was studied two types of electrochemical reactors: eletroflocculation and eletroflotation, with the aim of removing of Cu2+, Zn2+, phenol and BTEX mixture of produced water. In eletroflocculation, an electrical potential was applied to an aqueous solution containing NaCl. For this, it was used iron electrodes, which promote the dissolution of metal ions, generating Fe2+ and gases which, in appropriate pH, promote also clotting-flocculation reactions, removing Cu2+ and Zn2+. In eletroflotation, a carbon steel cathode and a DSA type anode (Ti/TiO2-RuO2-SnO2) were used in a NaCl solution. It was applied an electrical current, producing strong oxidant agents as Cl2 and HOCl, increasing the degradation rate of BTEX and phenol. Under different flow rates, the Zn2+ was removed by electrodeposition or by ZnOH formation, due the increasing of pH during the reaction. To better understand the electrochemical process, a statistical protocol factor (22) with central point was conducted to analyze the sensitivity of operating parameters on removing Zn2+ by eletroflotation, confirming that the current density affected the process negatively and the flow rate positively. For economical viability of these two electrochemical treatments, the energy consumption was calculated, taking in account the kWh given by ANEEL. The treatment cost obtained were quite attractive in comparison with the current treatments used in Rio Grande do Norte state. In addition, it could still be reduced for the case of using other alternative energy source such as solar, wind or gas generated directly from the Petrochemical Plant or offshore platforms

Avaliação da atividade antioxidante e antiproliferativa do extrato aquoso de frutas tropicais

The antioxidant activity of aqueous extracts of five edible tropical fruits (Spondias lutea, Hancornia speciosa, Spondias purpurea, Manilkara zapota and Averrhoa carambola) was investigated using different methods. The amount of phenolic compounds was determined by the Folin-Ciocalteu reagent. The M. zapota had Total Antioxidant Capacity (TAC) higher than the other fruits. Extracts showed neither reducing power nor iron chelation (between 0.01 and 2.0 mg/mL). H. speciosa exhibited the highest superoxide scavenging activity (80%, 0.5 mg/mL). However, at high concentrations (8.0 mg/mL) only A. carambola, S. purpurea and S. lutea scavenging 100% of radicals formed. M. zapota and S. purpurea had higher phenolic compound levels and greater OH radical scavenging activity (92 %, 2.0 mg/mL). Antiproliferative activity was assessed with 3T3 fibroblasts and cervical tumor cells (HeLa). The most potent extract was S. purpurea (0.5 mg/mL), which inhibited HeLa cell proliferation by 52%. The most fruits showed antioxidant and antiproliferative properties, characterizing them as functional foods.

Antenas e superfícies seletivas de freqüência reconfiguráveis para sistemas de comunicação sem fio

This work aims to present how the reconfigurable microstrip antennas and frequency selective surfaces can be used to operate at communication systems that require changing their operation frequency according to system requirements or environmental conditions. The main purpose is to present a reconfigurable circular microstrip antenna using a parasitic ring and a reconfigurable dipole frequency selective surface. Thereupon there are shown fundamental topics like microstrip antennas, PIN diodes and the fundamental theory of reconfigurable antennas and frequency selective surfaces. There are shown the simulations and measurements of the fabricated prototypes and it is done an analysis of some parameters like the bandwidth and radiation pattern, for the antennas, and the transmission characteristics, for the frequency selective surface. Copper strips were used in place of the diodes for proof of the reconfigurability concept

Avaliação da remoção de sulfeto de hidrogênio do gás natural em uma coluna de absorção

Natural gas, although basically composed by light hydrocarbons, also presents in its composition gaseous contaminants such as CO2 (carbon dioxide) and H2S (hydrogen sulfide). Hydrogen sulfide, which commonly occurs in oil and gas exploration and production activities, besides being among the gases that are responsible by the acid rain and greenhouse effect, can also cause serious harm to health, leading even to death, and damages to oil and natural gas pipelines. Therefore, the removal of hydrogen sulfide will significantly reduce operational costs and will result in oil with best quality to be sent to refinery, thereby resulting in economical, environmental, and social benefits. These factors highlight the need for the development and improvement of hydrogen sulfide sequestrating agents to be used in the oil industry. Nowadays there are several procedures for hydrogen sulfide removal from natural gas used by the petroleum industry. However, they produce derivatives of amines that are harmful to the distillation towers, form insoluble precipitates that cause pipe clogging and produce wastes of high environmental impact. Therefore, the obtaining of a stable system, in inorganic or organic reaction media, that is able to remove hydrogen sulfide without forming by-products that affect the quality and costs of natural gas processing, transport and distribution is of great importance. In this context, the evaluation of the kinetics of H2S removal is a valuable procedure for the treatment of natural gas and disposal of the byproducts generated by the process. This evaluation was made in an absorption column packed with Raschig ring, where natural gas with H2S passes through a stagnant solution, being the contaminant absorbed by it. The content of H2S in natural gas in column output was monitored by an H2S analyzer. The comparison between the obtained curves and the study of the involved reactions have not only allowed to determine the efficiency and mass transfer controlling step of the involved processes but also make possible to effect a more detailed kinetic study and evaluate the commercial potential of each reagent

Análise dos Processos de Flotação e Oxidação Avançada para o Tratamento de Efluente Modelo da Indústria do Petróleo

The generation of wastes in most industrial process is inevitable. In the petroleum industry, one of the greatest problems for the environment is the huge amount of produced water generated in the oil fields. This wastewater is a complex mixture and present great amounts. These effluents can be hazardous to the environmental without adequate treatment. This research is focused in the analysis of the efficiencies of the flotation and photo-oxidation processes to remove and decompose the organic compounds present in the produced water. A series of surfactants derivated from the laurilic alcohol was utilized in the flotation to promote the separation. The experiments have been performed with a synthetic wastewater, carefully prepared with xylene. The experimental data obtained using flotation presented a first order kinetic, identified by the quality of the linear data fitting. The best conditions were found at 0.029 g.L-1 for the surfactant EO 7, 0.05 g.L-1 for EO 8, 0.07 g.L-1 for EO 9, 0.045 g.L-1 for EO 10 and 0.08 g.L-1 for EO 23 with the following estimated kinetic constants: 0.1765, 0.1325, 0.1210, 0.1531 and 0.1699 min-1, respectively. For the series studied, the most suitable surfactant was the EO 7 due to the lower reagent onsumption, higher separation rate constant and higher removal efficiency of xylene in the aqueous phase (98%). Similarly to the flotation, the photo-Fenton process shows to be efficient for degradation of xylene and promoting the mineralization of the organic charge around 90% and 100% in 90 min

Conversão catalítica de clorometano em hidrocarbonetos

Amorphous silica-alumina and modified by incipient impregnation of iron, nickel, zinc and chromium were synthetized in oxide and metal state and evaluated as catalysts for the chloromethane conversion reaction. With known techniques their textural properties were determined and dynamics techniques in programmed temperature were used to find the acid properties of the materials. A thermodynamic model was used to determine the adsorption and desorption capacity of chloromethane. Two types of reactions were studied. Firstly the chloromethane was catalytically converted to hydrocarbons (T = 300 450 oC e m = 300 mg) in a fixed bed reactor with controlled pressure and flow. Secondly the deactivation of the unmodified support was studied (at 300 °C and m=250 g) in a micro-adsorver provided of gravimetric monitoring. The metal content (2,5%) and the chloromethane percent of the reagent mixture (10% chloromethane in nitrogen) were fixed for all the tests. From the results the chloromethane conversion and selectivity of the gaseous products (H2, CH4, C3 and C4) were determined as well as the energy of desorption (75,2 KJ/mol for Ni/Al2O3-SiO2 to 684 KJ/mol for the Zn/Al2O3-SiO2 catalyst) considering the desorption rate as a temperature function. The presence of a metal on the support showed to have an important significance in the chloromethane condensation. The oxide class catalyst presented a better performance toward the production of hydrocarbons. Especial mention to the ZnO/Al2O3-SiO2 that, in a gas phase basis, produced C3 83 % max. and C4 63% max., respectively, in the temperature of 450 oC and 20 hours on stream. Hydrogen was produced exclusively in the FeO/Al2O3-SiO2 catalysts (15 % max., T = 550 oC and 5,6 h on stream) and Ni/SiO2-Al2O3 (75 % max., T = 400 oC and 21,6 h on stream). All the catalysts produced methane (10 à 92 %), except for Ni/Al2O3-SiO2 and CrO/Al2O3-SiO2. In the deactivation study two models were proposed: The parallel model, where the product production competes with coke formation; and the sequential model, where the coke formation competes with the product desorption dessorption step. With the mass balance equations and the mechanism proposed six parameters were determined. Two kinetic parameters: the hydrocarbon formation constant, 8,46 10-4 min-1, the coke formation, 1,46 10-1 min-1; three thermodynamic constants (the global, 0,003, the chloromethane adsorption 0,417 bar-1, the hydrocarbon adsorption 2,266 bar-1), and the activity exponent of the coke formation (1,516). The model was reasonable well fitted and presented a satisfactory behavior in relation with the proposed mechanism

Análise dos Processos de Flotação e Oxidação Avançada para o Tratamento de Efluente Modelo da Indústria do Petróleo

The generation of wastes in most industrial process is inevitable. In the petroleum industry, one of the greatest problems for the environment is the huge amount of produced water generated in the oil fields. This wastewater is a complex mixture and present great amounts. These effluents can be hazardous to the environmental without adequate treatment. This research is focused in the analysis of the efficiencies of the flotation and photo-oxidation processes to remove and decompose the organic compounds present in the produced water. A series of surfactants derivated from the laurilic alcohol was utilized in the flotation to promote the separation. The experiments have been performed with a synthetic wastewater, carefully prepared with xylene. The experimental data obtained using flotation presented a first order kinetic, identified by the quality of the linear data fitting. The best conditions were found at 0.029 g.L-1 for the surfactant EO 7, 0.05 g.L-1 for EO 8, 0.07 g.L-1 for EO 9, 0.045 g.L-1 for EO 10 and 0.08 g.L-1 for EO 23 with the following estimated kinetic constants: 0.1765, 0.1325, 0.1210, 0.1531 and 0.1699 min-1, respectively. For the series studied, the most suitablesurfactant was the EO 7 due to the lower reagent consumption, higher separation rate constant and higher removal efficiency of xylene in the aqueous phase (98%). Similarly to the flotation, the photo-Fenton process shows to be efficient for degradation of xylene and promoting the mineralization of the organic charge around 90% and 100% in 90 min

Reflexões sobre a política de descentralização em saúde: uma análise a partir do Hospital Monsenhor Walfredo Gurgel em Natal (RN)

The process of decentralization of health policy in Brazil has evolved throughout the second half of the twentieth century, advancing by leaps and bounds in the last two decades. The various public institutions have assumed the function of responding to a growing demand for medical care and hospital. Monsenhor Hospital Walfredo Gurgel - H.M.W.G. fits into this context as an institution par excellence-oriented service the demand for medium and high complexity. This paper presents some questions about the process of decentralization and devolution occurred in Brazil. To do so is a brief historical background and politics, showing the concepts of reform and counter-reform and how the processes mentioned in the Country Correlates develop local social development of the decentralization process and discusses the modifications in policies social intervention in recent decades and the state health policies. Presents the implementation of a Health System in Brazil and the state showing how the decentralization of health policy occurs in Rio Grande do Norte. Finally, it explores the role of H.M.W.G. in health policy in RN. For this, portrays the institution and is located within the decentralized structure of health policy in the state and capital. An analysis of the demand for hospital care and the budget situation is realized at the close of work, correlating the role of HMWG with the decentralization of health policy in Brazil and Rio Grande do Norte. The methodology used for the preparation of this work was based on documentary research, systematic nonparticipant observation, field diary and analysis of data, documents and content. This set shows a quantitative and qualitative methodology that strips the institution, enabling the understanding of their role, boundaries, threats and opportunities

JCML - Java Card Modeling Language: Definição e Implementação

Formal methods should be used to specify and verify on-card software in Java Card applications. Furthermore, Java Card programming style requires runtime verification of all input conditions for all on-card methods, where the main goal is to preserve the data in the card. Design by contract, and in particular, the JML language, are an option for this kind of development and verification, as runtime verification is part of the Design by contract method implemented by JML. However, JML and its currently available tools for runtime verification were not designed with Java Card limitations in mind and are not Java Card compliant. In this thesis, we analyze how much of this situation is really intrinsic of Java Card limitations and how much is just a matter of a complete re-design of JML and its tools. We propose the requirements for a new language which is Java Card compliant and indicate the lines on which a compiler for this language should be built. JCML strips from JML non-Java Card aspects such as concurrency and unsupported types. This would not be enough, however, without a great effort in optimization of the verification code generated by its compiler, as this verification code must run on the card. The JCML compiler, although being much more restricted than the one for JML, is able to generate Java Card compliant verification code for some lightweight specifications. As conclusion, we present a Java Card compliant variant of JML, JCML (Java Card Modeling Language), with a preliminary version of its compiler

Dinâmica sazional de fungos micorrízicos arbusculares (Glomeromycota) em cerradão e brejo de altitude na Chapada do Araripe, CE

Arbuscular mycorrhizal fungi (AMF) are obligatory symbiotic organisms that associate with roots of a large number of plant taxa, and are found in all terrestrial ecosystems. These fungi promote greater tolerance to environmental stresses to associated plant, favoring the establishment of plant communities, especially where soil fertility is a limiting factor, as in the Caatinga, an exclusively Brazilian domain that has been focus of research due to its great biodiversity that can help clarify the history of vegetation in South America. Because of the ecological importance of AMF, the limited number of jobs and the potential diversity of the Caatinga, this work aims to inventory the diversity and determine AMF communities in areas with different faces occurrent in FLONA Araripe, Ceará (CE). The sample collection occurred in four periods at the beginning and end of the dry season (August and December 2011, respectively) and rainy (February and June 2012, respectively) in an area of marsh and woodland altitude of the Araripe, Crato, CE. The glomerosporos were extracted by wet sieving and centrifugation in water and sucrose (50%) mounted between slide and coverslip using PVLG and PVLG + Reagent Melzer. In total, we found 46 species of AMF distributed in eight families and 16 genera: Acaulospora (6), Ambispora (1), Cetraspora (2), Dentiscutata (5), Fuscutata (2), Gigaspora (6), Glomus (13) Intraornatospora (1), Kuklospora (1), Orbispora (1), Paradentiscutata (1), Quatunica (1), Racocetra (1), Scutellospora (2), Septoglomus (2) and a new genus. analysis showed that ecological each area of study has its own seasonal dynamics, with an area of woodland with a greater diversity of species throughout the year, while the marsh elevation showed greater variation in species found among the collection periods, showing that vegetation and rainfall has strong influence on the seasonal dynamics of AMF, as well as the availability of nutrients and soil pH so

Sistemas computacionais espaço-temporais para toma de decisão em questões ambientais relacionadas à indústria de petróleo e gás

The area between São Bento do Norte and Macau cities, located in the northern coast of the Rio Grande do Norte State is submitted to intense and constant processes of littoral and aeolian transport, causing erosion, alterations in the sediments balance and modifications in the shoreline. Beyond these natural factors, the human interference is huge in the surroundings, composed by sensitive places, due to the existence of the Guamaré Petroliferous Pole, RN, the greater terrestrial oil producing in Brazil, besides the activities of the salt companies and shrimp farms. This socioeconomic-environmental context justifies the elaboration of strategies of environmental monitoring of that coastal area. In the environmental monitoring of coastal strips, submitted to human impacts, the use of multi-sources and multitemporal data integrated through a Spatio- Temporal Database that allows the multiuser friendly access. The objective was to use the potential of the computational systems as important tools the managers of environmental monitoring. The stored data in the form of a virtual library aid in making decisions from the related results and presented in different formats. This procedure enlarges the use of the data in the preventive attendance, in the planning of future actions and in the definition of new lines of researches on the area, in a multiscale approach. Another activity of this Thesis consisted on the development of a computational system to automate the process to elaborate Oil-Spill Environmental Sensitivity Maps, based on the temporal variations that some coastal ecosystems present in the sensibility to the oil. The maps generated in this way, based on the methodology proposed by the Ministério do Meio Ambiente, supply more updated information about the behavior of the ecosystem, as a support to the operations in case of oil spill. Some parameters, such as the hydrodynamic data, the declivity of the beach face, types of resources in risk (environmental, economical, human or cultural) and use and occupation of the area are some of the essential basic information in the elaboration of the sensitivity maps, which suffer temporal alterations.In this way, the two computational systems developed are considered support systems to the decision, because they provide operational subsidies to the environmental monitoring of the coastal areas, considering the transformations in the behavior of coastal elements resulting from temporal changes related the human and/or natural interference of the environment

Atividade antiinflamatória de uma heterofucana da alga marrom Padina gymnospora

Fucans, sulfated polysaccharides extracted from brown algae and some echinoderms, have been extensively studied for its diverse biological activities and because of its interference with molecular mechanisms of cell to cell recognition, including leukocyte trafficking from blood vessels into sites of inflammation mediated by selectin, a family of adhesion molecules. In the present study, we examined structural features of a heterofucan extracted from brown algae Padina gymnospora and its effect on the leukocyte migration to the peritoneum. The sulfated polysaccharides were extracted from the brown seaweed by proteolysis with the proteolytic enzyme maxatase. The presence of protein and uronic acid contamination was detected in the crude polysaccharide extract. Fractionation of the crude extract with growing concentrations of acetone produced five fractions with different concentrations of fucose, xylose, uronic acid, galactose, glucose and sulfate. The fraction precipitated with 1.5 volumes of acetone was characterized by infrared and nuclear magnetic resonance, through which can be observed the presence of sulfate groups in the C4 of -L-fucose. The anti-inflammatory action of this composite was assessed by a sodium thioglycollate-induced peritonitis assay and through nitric oxide production by the peritoneal macrophages using Griess reagent. Fraction F1.5 was efficient in reducing leukocyte influx into the peritoneal cavity when 10 mg/kg and 25mg/kg were used, resulting in a decrease of 56 and 39%, respectively. A decrease of nitric oxide production occurred when high concentrations of fucana were used. The cytotoxicity of the composite was also assessed using the reduction of 3-(4,5 dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT). Fraction F1.5 had no cytotoxicity when 500 μg/mL of the fraction was used. This study suggests the use of fraction F1.5 (heterofucan) as an anti-inflammatory

Desenvolvimento de uma rota química alternativa de síntese de SrCo0,8Fe0,2O3- e LaNi0,3Co0,7O3- para aplicação na reação de oxidação do CO

This thesis focuses on the coprecipitation synthesis method for preparation of ceramic materials with perovskite structure, their characterization and application as catalytic material in the reaction of converting CO to CO2 developing a methodological alternative route of synthesis from the middle via oxalate coprecipitation material SrCo0,8Fe0,2O3-d. In order to check the influence of this method, it was also synthesized using a combined citrate - EDTA complexing method. The material was characterized by: X-ray diffraction (XRD), Rietveld refinement method, thermogravimetry and differential thermo analysis (TG / DTA), scanning (SEM) and transmission (TEM) electron microscopy, particle size distribution and surface analysis method BET. Both methods led to post-phase synthesis, with pH as a relevant parameter. The synthesis based on the method via oxalate coprecipitation among particles led to the crystalline phase as those obtained using a combined citrate - EDTA complexing method under the same conditions of heat treatment. The nature of the reagent used via oxalate coprecipitation method produced a material with approximately 80 % lower than the average size of crystallites. Moreover, the via oxalate coprecipitation method precursors obtained in the solid state at low temperature (~ 26 oC), shorter synthesis, greater thermal stability and a higher yield of around 90-95 %, maintaining the same order of magnitude the crystallite size that the combined citrate - EDTA complexing method. For purposes of comparing the catalytic properties of the material was also synthesized by the using a combined citrate - EDTA complexing method. The evaluation of catalytic materials SrCo0,8Fe0,2O3-d LaNi0,3Co0,7O3-d was accompanied on the oxidation of CO to CO2 using a stainless steel tubular reactor in the temperature range of 75-300 oC. The conversion CO gas was evaluated in both materials on the results shaved that the firm conversion was loves for the material LaNi0,3Co0,7O3-d

Mapeamento da zona costeria protegida por arenitos de praia (Beachrocks) em Nísia Floresta - RN

The goal of this work comprises the detailed mapping of the coastal zone of the south coast of the State of Rio Grande do Norte. The emphasis of the study is the units of beachrocks and the features of the physical environment associated. The mapping of the beachrocks and of the adjacent coastal features is justified, among other aspects, by the fact that the beachrocks constitute an important protection agent against the sea erosion. By one side, they dissipate the energy of the sea waves and make possible the imprisonment of sediments in the foreshore. The beachrocks in the studied area are constituted of discontinuous strips, parallel to the coast line presenting emerged in some places, even in the highest tides, entirely submerged or partially buried by coastal sediments. These sandstones compose the landscape of big part of the coast and they are responsible for the partial dissipation of the energy of the waves on the studied coast. The methodology used in this work consisted of different techniques were used, as the use of aerial pictures of small format (FAPEFs), acquisition of data of system of global positioning (GPS) and later elaboration of thematic maps and of digital models of soil (MDTs). The results obtained in the mapping of the use and occupation of the soil, demonstrate the existence of strong human pressure in the coastal area (built lots and no built), occupying about 54,74% of built areas. This problem has been taking to degradation risks due to the inconsequent expansion of divisions into lots and tourist enterprises. The MDT came as an excellent resource, as visual as functional, being possible to visualize several angles and to act in three dimensions the relief of the area in study, as well as to identify the present features in the coastal area. By the importance of the bodies of beachrocks as a protection agent against the coastal erosion, faces were delimited in the sandstones based in geometric criteria, classifying them in, central face, outside face, inside face, break and undermiming. These last two associates to the erosion and washout in the base of these bodies. Field data indicate clearly that the most important process in the fracturing of the bodies is associated with mechanisms related to the gravity, being the joints formed by processes of gravitational sliding. Finally, the mapping of the coastal zone starting from aerial pictures of small format it made possible the identification of the elements that compose the beach strip, for accomplishing with larger detailed level and by presenting a better monitoring of the dynamics of the coastal zone