Comportamento da adição do carbeto de nióbio (nBC) na matriz metálica do aço ferrítico 15kH2mfa

The 15Kh2MFA steel is a kind of Cr-Mo-V family steels and can be used in turbines for energy generation, pressure vessels, nuclear reactors or applications where the range of temperature that the material works is between 250 to 450°C. To improve the properties of these steels increasing the service temperature and the thermal stability is add a second particle phase. These particles can be oxides, carbides, nitrites or even solid solution of some chemical elements. On this way, this work aim to study the effect of addition of 3wt% of niobium carbide in the metallic matrix of 15Kh2MFA steel. Powder metallurgy was the route employed to produce this metallic matrix composite. Two different milling conditions were performed. Condition 1: milling of pure 15Kh2MFA steel and condition 2: milling of 15Kh2MFA steel with addition of niobium carbide. A high energy milling was carried out during 5 hours. Then, these two powders were sintered in a vacuum furnace (10-4torr) at 1150 and 1250°C during 60 minutes. After sintering the samples were normalized at 950°C per 3 minutes followed by air cooling to obtain a desired microstructure. Results show that the addition of niobium carbide helps to mill faster the particles during the milling when compared with that steel without carbide. At the sintering, the niobium carbide helps to sinter increasing the density of the samples reaching a maximum density of 7.86g/cm³, better than the melted steel as received that was 7,81g/cm³. In spite this good densification, after normalizing, the niobium carbide don t contributed to increase the microhardness. The best microhardness obtained to the steel with niobium carbide was 156HV and to pure 15Kh2MFA steel was 212HV. It happened due when the niobium carbide is added to the steel a pearlitic structure was formed, and the steel without niobium carbide submitted to the same conditions reached a bainitic structure

Diagnóstico da possível influência da atividade petrolífera em sedimentos de fundo da Bacia Piranhas-Açu, região Baixo Açu/RN

It is located in an area of increasing oil exploration, the region of the Lower Açu is at the mercy of a possible pollution generated by this economic activity, which includes various chemical substances harmful to health, such as metals. This thesis aims to, diagnose the areas of River Piranhas-Açu, a region of the Lower Açu, which are polluted by traces factors and more. In this study, it was determined the concentration of the chemica elements Al, CD, Cr, Cu, Fe, Mn, Ni, P, Pb, V and Zn, through the technique of ICP-OES analysis and the size of sediments and their contents organic matter. Were mapped by GPS, 12 points from collections. The interpretations of the results, together associating that allowed pollution to a possible contamination by oil activity. The results showed tha some regions have low concentrations of cadmium, lead, copper, manganese and zinc unable to promote damage to human health. However, there are places where the concentrations of certain metals chromium, iron and zinc are moderately polluted compared to the results with the reference values of literature and others that are highly polluted by iron. However, due to a greater number of wells in production in those locations, those higher concentrations, it can be suggested a possible influence of oi production in some areas with concentrations of chromium and lead are higher than the rest of the points of monitoring. Moreover, it is observed that the highest levels of metals found in sediment of finer texture and more organic matter content

Estudo da detecção preventiva da osteoporose pela aplicação da variação da permissividade elétrica a partir da sondagem eletromagnética

This paper proposes a method based on the theory of electromagnetic waves reflected to evaluate the behavior of these waves and the level of attenuation caused in bone tissue. For this, it was proposed the construction of two antennas in microstrip structure with resonance frequency at 2.44 GHz The problem becomes relevant because of the diseases osteometabolic reach a large portion of the population, men and women. With this method, the signal is classified into two groups: tissue mass with bony tissues with normal or low bone mass. For this, techniques of feature extraction (Wavelet Transform) and pattern recognition (KNN and ANN) were used. The tests were performed on bovine bone and tissue with chemicals, the methodology and results are described in the work

A tabela periódica: um recurso para a inclusão de alunos deficientes visuais nas aulas de química

Nowadays there are many reasons that aim to include people with special necessities, like those with visual deficiency, in the world of work, education, and in the society as a whole. However it is observed that when we talk about schooling inclusion, especially in High School, there is a huge gap between the theory and the practice. The lack of didactic resources, the inadequate installations, unprepared teachers, the families´ lack of information, are some of the factors that hinder the process of inclusion. Furthermore, the educators also have to deal with the roughness of the disciplinary contents and, refering to the study of Chemistry, with the use of signals related to this subject´s language. So, the objective of our research is to reflect about the apprehension of this language by the visually handicapped people, and try to contribute with their process of inclusion in the school life. On this perspective we work with the Periodic Table, which constitutes one of the indispensable tools necessary to the Chemistry learning. In order to acomplish it, the way followed by us happened in three passages. Initially, by means of a semistructured interview, we tried to get acquainted with the blind students opinion, who were participating in the research about the Periodic Table used by them throughout High School, as well as the dificulties felt when using it. After getting the answers, the Table was reelaborated to fill those students´necessities. Here, two new Tables were designed, one in Braille which shape is more compacted, and another made with high printed dots, built with sand and glue. On the third moment, the new designed Tables were tested by the students and, by means of a semi-structured interview, we tried to identify if this new resource would solve the problems concerned to the old Table. The students showed that the compacted Tables would facilitate the touch reading of the chemical elements simbols, making it clear and fast. We hope that, with the elaboration of this learning tools we can contribute with one of the elements to favor the effective participation of blind students in Chemistry classes, when studying the Periodic Table

Deposição de filmes de ZrO2 modificados sobre substratos metálicos

This work makes use of the Pechini process for synthesis of the solutions and the dip-coating process for the addition of zirconium oxide films pure and doped cerium metal substrates. The metals with ceramic substrates were subjected to severe conditions of salinity. The x-ray fluorescence of the substrate showed a great diversity of chemical elements. The x-ray diffraction of the samples showed the phase of iron substrate because the thickness of nano-thin film. Tests using an LPR probe showed that the film presents with zirconia corrosion independent of film thickness. The substrates of ZrO2-doped ceria showed low chemical attack of the salt in films with less than 15 dives. The results imply that ultrathin films are shown in protecting metallic substrates

Sobre a composição química em estrelas evoluídas do aglomerado aberto M67

The Galaxy open clusters have a wide variety of physical properties that make them valuable laboratories for studies of stellar and chemical evolution of the Galaxy. In order to better settle these properties we investigate the abundances of a large number of chemical elements in a sample of 27 evolved stars of the open cluster M67 with different evolutionary stages (turn-off, subgiant and giant stars). For such a study we used high-resolution spectra (R 47 000) and high S/N obtained with UVES+FLAMES at VLT/UT2, covering the wavelength interval 4200-10 600 Å. Our spectral analysis is based on the MARCS models of atmosphere and Turbospectrum spectroscopic tool. The oxygen abundances were determined from the [O I] line at 6300 Å. In addition, we have also computed abundances of Si I, Na I, Mg I, Al I, Ca I, Ti I, Co I, Ni I, Zr I, La II and Cr I. The abundances investigated in this work, combined with their stellar parameters, offers an opportunity to determine the level of mixing and convective dilution of evolved stars in M67. Based on the obtained parameters, the abundances of these seem to follow a similar trend to the curve of solar abundances. Additionally, following strategies of other studies have investigated the relative abundances as a function of effective temperature and metallicity, where it was possible to observe an abundance of Na, Al and Si to the stars in the field of giants. A large dispersion from star to star, is observed in the ratios [X / Fe] for the Co, Zr and La, and the absence of Zr and La, in the stars of the turn-off. Comparisons made between our results and other studies in the literature show that values of abundances are in agreement and close to the limits of the errors

Estudo geoquímico e geocronológico Rb-Sr e Sm-Nd em zonas de cisalhamento mineralizadas em ouro e suas relações com as rochas encaixantes e geocronológico Sm-Nd em mineralizações de scheelita na faixa Seridó

Great part of the gold mineralizations are associated with shearing zones through which circulate a great volume of fluids, that interact with the host rocks, originating leaching or precipitation of chemical elements, including gold. The studied mineralizations are inserted in the Seridó Belt. The tungsten mineralization in Brejuí Mine is hosted in calcsilicate rocks from Jucurutu Formation. The São Francisco auriferous mineralization has as host rocks mica-schists from Seridó Formation, while the Ponta da Serra and Fazenda Simpático mineralizations are hosted in orthogneisses of this fold belt basement. The research conducted on these mineralizations had the purpose of integrate the data of chemical elements behavior during the shearing/mineralizing event, and its influence on the isotopic systems Rb-Sr and Sm-Nd. The studies of chemical mobility in the auriferous mineralizations showed that elements that during the shearing displayed in general an immobile behavior were Al, Ti and Zr. Among the elements that were mobilized during the event, K and Rb showed mass gain in ali belts of transformed rocks, while the elements Ca, Na and Sr normally lost mass. Petrographic studies showed that the minerais biotite and plagioclase, in all investigated mineralizations, played an important role in the chemical reactions occurred in the transformed rocks to the generation of muscovite, cordierite and sillimanite, justifying the input of K to the formation of muscovite, and the release of Na and Ca from plagioclase to the fluid phase. In the São Francisco auriferous mineralization, the results of the Rb-Sr isotopic analysis yielded ages of 645 ± 19 Ma and 596 ± 17 Ma, with both samples, from original and transformed rocks. Two ages, 569 ± 20 Ma. and 554 ± 19 Ma., were obtained with samples frem the transformed rocks domain. These ages suggest that there were two metamorphic pulses during the emplacement of the mineralized shearing zone. The Sm-Nd data yielded TDM ages of 1,31 Ga and 1,26 Ga with 3Nd (0,6 Ga) of -0,26 e -0,40 for the original and final transformed rocks, respectively. In case of the orthogneisses of Caicó Complex, e.g. the Ponta da Serra and Fazenda Simpático mineralizations, the Rb-Sr data did not yield ages with geological significance. In the Ponta da Serra mineralization, the Sm-Nd isotopic data yielded T DM ages of 2,56 Ga and 2,63 Ga to the original rocks and of 2,71 Ga to the mineralized sheared rock, and values of 3Nd (2,0 Ga) between -3,70 e -5,42 to the original and sheared rock, respectively. In the Fazenda Simpático, Sm-Nd data yielded TDM between 2,65 and 2,69 Ga with values of 3Nd (2,0 Ga) between -5,25 e -5,52. Considering the Sm-Nd data, the TDM ages may be admitted as the age of the parental magma extraction, producer of the protoliths of the orthogneisses from Ponta da Serra and Fazenda Simpático mineralizations. The chemical mobility studies showed that in the basement hosted mineralizations, Rb achieved mass while Sr lost mass, as Sm as well as Nd were strongly mobilized. The Sm/Nd ratio remained constant, however, confirming the isochemical character of those elements. In the basement mineralizations, Rb-Sr ages are destituted of geological significance, because of the partial opening of the isotopic system during the tectono-metamorphic transformations. In the tungsten mineralization, the diagram Sm-Nd constructed with the whole-rock data of calcsilicatic and the high-temperature paragenesis (garnet, diopside and iron-pargasitic hornblende) indicated an 631 ± 24 Ma age, while with the whole-rock data and low-temperature paragenesis (vesuvianite, epidote and calcite), a 537 ± 107 Ma age was obtained. These ages, associated with the petrographic observations, suggest that there was a time gap among the hydrothernal events responsible by the formation of the high and low temperature paragenesis in the calcsilicatic rocks mineralized in scheelite

Foraminíferos, ostracodes e microfauna associada da plataforma continental equatorial norte-rio-grandense, NE Brasil: área Porto do Mangue a Galinhos

This study was conducted in the adjacent Brazilian equatorial inner shelf to Rio Grande do Norte, between the region of Porto do Mangue and Galinhos. The main objective is the characterization of biogenic sediments, especially foraminifera and ostracod collected on the surface of the seafloor. The methodology involved standard procedures including literature, surveys, processing of samples in the laboratory and identification of foraminifera and ostracods by genera or species under stereo microscopy and scanning electron microscopy (SEM). Multivariate statistical analyzes and study of ecological indexes were also applied to the study of foraminifera. Three transects, from inner shelf to slope were sampled: profile 01 (east, near Galos), profile 02 (center, near the city of Macau) and profile 03 (west, near Ponta do Mel). Results indicated the predominance of benthic foraminifera and little plankton occurrence. Benthic foraminifera genera observed in abundance were Quinqueloculina, Textularia, Globigerina and Pyrgo, Quinqueloculina, Textularia, Pyrgo, Ammonia, Elphidium, Pseudononion, Peneroplis, Bolivina and Poroeponides, occurred more frequently. Less frequently been described Amphistegina, Archaias, Bigenerina, Cibicides, Cassidulina, Amphicorina, Cornuspira, Paterina, Hopkunsina, Oolina, Uvigerina, Fusenkoina, Nonionella, Amphisorus, Wiesrella, Reussella, Reophax, Nodosaria, Marginulina and Cyclogyra. Six genera of ostracods were also identified: Puriana variabilis / P. convoluted?, Loxoconcha sp, Bairdiidae, Xestoleberis sp, Hemicytheridae and Ruggiericythere sp. Groups of organisms found in the studied shelf presented chemical composition of Ca, C, O, Na, Cl, Al, Mg, and Si. The proportions of chemical elements may vary according to the type of biogenic sediment, with the highest values identified as Ca, C, Cl, Na and O. The absolute dating by carbon 14 method indicated sediments of different colors (light and dark), correspond to a single age from 3000 to 6000 years BP, related to the Quaternary. These data intend to complement information about biogenic sediments in the Brazilian continental shelf, especially in the Northeast, where there is a lack of such studies.

Foraminíferos, ostracodes e microfauna associada da plataforma continental equatorial norte-rio-grandense, NE Brasil: área Porto do Mangue a Galinhos

This study was conducted in the adjacent Brazilian equatorial inner shelf to Rio Grande do Norte, between the region of Porto do Mangue and Galinhos. The main objective is the characterization of biogenic sediments, especially foraminifera and ostracod collected on the surface of the seafloor. The methodology involved standard procedures including literature, surveys, processing of samples in the laboratory and identification of foraminifera and ostracods by genera or species under stereo microscopy and scanning electron microscopy (SEM). Multivariate statistical analyzes and study of ecological indexes were also applied to the study of foraminifera. Three transects, from inner shelf to slope were sampled: profile 01 (east, near Galos), profile 02 (center, near the city of Macau) and profile 03 (west, near Ponta do Mel). Results indicated the predominance of benthic foraminifera and little plankton occurrence. Benthic foraminifera genera observed in abundance were Quinqueloculina, Textularia, Globigerina and Pyrgo, Quinqueloculina, Textularia, Pyrgo, Ammonia, Elphidium, Pseudononion, Peneroplis, Bolivina and Poroeponides, occurred more frequently. Less frequently been described Amphistegina, Archaias, Bigenerina, Cibicides, Cassidulina, Amphicorina, Cornuspira, Paterina, Hopkunsina, Oolina, Uvigerina, Fusenkoina, Nonionella, Amphisorus, Wiesrella, Reussella, Reophax, Nodosaria, Marginulina and Cyclogyra. Six genera of ostracods were also identified: Puriana variabilis / P. convoluted?, Loxoconcha sp, Bairdiidae, Xestoleberis sp, Hemicytheridae and Ruggiericythere sp. Groups of organisms found in the studied shelf presented chemical composition of Ca, C, O, Na, Cl, Al, Mg, and Si. The proportions of chemical elements may vary according to the type of biogenic sediment, with the highest values identified as Ca, C, Cl, Na and O. The absolute dating by carbon 14 method indicated sediments of different colors (light and dark), correspond to a single age from 3000 to 6000 years BP, related to the Quaternary. These data intend to complement information about biogenic sediments in the Brazilian continental shelf, especially in the Northeast, where there is a lack of such studies.

Pirometamorfismo em calcários da formação Jandaíra, bacia potiguar, nordeste do Brasil

The present study aims the characterization of thermally affected carbonate rocks from Jandaíra Formation in contact with Paleogene and Neogene basic intrusions in the region of the Pedro Avelino and Jandaíra municipalities (RN), northeastern Brazil. For this study, field, petrographic, x-ray diffraction, electron microprobe, and whole rock litogeochemistry data of carbonates were undertaken. The thermally unaffected limestones are classified like wackstones, grainstones and packstones. They may constitute carbonates grains of benthic foraminifera, echinoderm spines, ostracods, algae, corals, bivalves, gastropods, peloids and intraclasts. The porosities are classified like vug, intraparticle, interparticle, intercrystal and moldic types. The major minerals are calcite, ankerite and dolomite; the detrital are montmorillonite, pyrite, limonite, quartz and microcline. The thermally affected limestones are very coarse to very fine-grained and light to dark gray color. The fossiliferous components totally disappear, and the porosity tends to disappear. With the data obtained, it can be inferred that the carbonate protoliths would be calciferous to dolomitic limestones, both with small amount of clay minerals. Crystalline carbonates from dolomitic protolith have rhombohedral calcite and iron oxides / hydroxides, making the rocks much darker. The carbonates from calciferous protolith have a wide variation of grain size according to the recrystallization degree, increasing toward contact with the basic bodies. In this group, it was identified the minerals lizardite and spinel in weakly to moderately affected samples, and spinel and spurrite in strongly affected rocks, as well as calcite, that occur everywhere. The geological context (shallow level diabase intrusions), the crystallization of the pyrometamorphic minerals spurrite and olivine, and comparison with diagrams from the literature allow estimating temperatures and pressures around 1050-1200 °C and 0.5-1.0 kbar, respectively, for PTOTAL=PCO2. The post-intrusion cooling would have afforded the releasing of metasomatic / hydrothermal fluids, allowing the opening of the metamorphic system, with possible contribution of chemical elements from host units (sandstones, shales) and from basic intrusions. This would induce hydration of previous phases, allowing the formation of serpentine, chlorite and brucite. The results discussed here reveal the strong influence of the heat from basic intrusions within the sedimentary pile. Whereas in the offshore portion of the basin occur sills with up to 1000 m thickness, the understanding of pyrometamorphism might be useful for understanding and measuring the thermally affected rocks.

Pirometamorfismo em calcários da formação Jandaíra, bacia potiguar, nordeste do Brasil

The present study aims the characterization of thermally affected carbonate rocks from Jandaíra Formation in contact with Paleogene and Neogene basic intrusions in the region of the Pedro Avelino and Jandaíra municipalities (RN), northeastern Brazil. For this study, field, petrographic, x-ray diffraction, electron microprobe, and whole rock litogeochemistry data of carbonates were undertaken. The thermally unaffected limestones are classified like wackstones, grainstones and packstones. They may constitute carbonates grains of benthic foraminifera, echinoderm spines, ostracods, algae, corals, bivalves, gastropods, peloids and intraclasts. The porosities are classified like vug, intraparticle, interparticle, intercrystal and moldic types. The major minerals are calcite, ankerite and dolomite; the detrital are montmorillonite, pyrite, limonite, quartz and microcline. The thermally affected limestones are very coarse to very fine-grained and light to dark gray color. The fossiliferous components totally disappear, and the porosity tends to disappear. With the data obtained, it can be inferred that the carbonate protoliths would be calciferous to dolomitic limestones, both with small amount of clay minerals. Crystalline carbonates from dolomitic protolith have rhombohedral calcite and iron oxides / hydroxides, making the rocks much darker. The carbonates from calciferous protolith have a wide variation of grain size according to the recrystallization degree, increasing toward contact with the basic bodies. In this group, it was identified the minerals lizardite and spinel in weakly to moderately affected samples, and spinel and spurrite in strongly affected rocks, as well as calcite, that occur everywhere. The geological context (shallow level diabase intrusions), the crystallization of the pyrometamorphic minerals spurrite and olivine, and comparison with diagrams from the literature allow estimating temperatures and pressures around 1050-1200 °C and 0.5-1.0 kbar, respectively, for PTOTAL=PCO2. The post-intrusion cooling would have afforded the releasing of metasomatic / hydrothermal fluids, allowing the opening of the metamorphic system, with possible contribution of chemical elements from host units (sandstones, shales) and from basic intrusions. This would induce hydration of previous phases, allowing the formation of serpentine, chlorite and brucite. The results discussed here reveal the strong influence of the heat from basic intrusions within the sedimentary pile. Whereas in the offshore portion of the basin occur sills with up to 1000 m thickness, the understanding of pyrometamorphism might be useful for understanding and measuring the thermally affected rocks.

Comportamento da adição do carbeto de nióbio (nBC) na matriz metálica do aço ferrítico 15kH2mfa

The 15Kh2MFA steel is a kind of Cr-Mo-V family steels and can be used in turbines for energy generation, pressure vessels, nuclear reactors or applications where the range of temperature that the material works is between 250 to 450°C. To improve the properties of these steels increasing the service temperature and the thermal stability is add a second particle phase. These particles can be oxides, carbides, nitrites or even solid solution of some chemical elements. On this way, this work aim to study the effect of addition of 3wt% of niobium carbide in the metallic matrix of 15Kh2MFA steel. Powder metallurgy was the route employed to produce this metallic matrix composite. Two different milling conditions were performed. Condition 1: milling of pure 15Kh2MFA steel and condition 2: milling of 15Kh2MFA steel with addition of niobium carbide. A high energy milling was carried out during 5 hours. Then, these two powders were sintered in a vacuum furnace (10-4torr) at 1150 and 1250°C during 60 minutes. After sintering the samples were normalized at 950°C per 3 minutes followed by air cooling to obtain a desired microstructure. Results show that the addition of niobium carbide helps to mill faster the particles during the milling when compared with that steel without carbide. At the sintering, the niobium carbide helps to sinter increasing the density of the samples reaching a maximum density of 7.86g/cm³, better than the melted steel as received that was 7,81g/cm³. In spite this good densification, after normalizing, the niobium carbide don t contributed to increase the microhardness. The best microhardness obtained to the steel with niobium carbide was 156HV and to pure 15Kh2MFA steel was 212HV. It happened due when the niobium carbide is added to the steel a pearlitic structure was formed, and the steel without niobium carbide submitted to the same conditions reached a bainitic structure

Diagnóstico da possível influência da atividade petrolífera em sedimentos de fundo da Bacia Piranhas-Açu, região Baixo Açu/RN

It is located in an area of increasing oil exploration, the region of the Lower Açu is at the mercy of a possible pollution generated by this economic activity, which includes various chemical substances harmful to health, such as metals. This thesis aims to, diagnose the areas of River Piranhas-Açu, a region of the Lower Açu, which are polluted by traces factors and more. In this study, it was determined the concentration of the chemica elements Al, CD, Cr, Cu, Fe, Mn, Ni, P, Pb, V and Zn, through the technique of ICP-OES analysis and the size of sediments and their contents organic matter. Were mapped by GPS, 12 points from collections. The interpretations of the results, together associating that allowed pollution to a possible contamination by oil activity. The results showed tha some regions have low concentrations of cadmium, lead, copper, manganese and zinc unable to promote damage to human health. However, there are places where the concentrations of certain metals chromium, iron and zinc are moderately polluted compared to the results with the reference values of literature and others that are highly polluted by iron. However, due to a greater number of wells in production in those locations, those higher concentrations, it can be suggested a possible influence of oi production in some areas with concentrations of chromium and lead are higher than the rest of the points of monitoring. Moreover, it is observed that the highest levels of metals found in sediment of finer texture and more organic matter content

Parâmetros físico-químicos de estrelas com planetas na missão CoRoT

In the present study we compute the atmospheric parameters (Teff , log g and vmic, [Fe/H]) and chemical abundance of 16 ions (Fe I, Fe II, O I, Si I, Na I, Mg I, Al I, Ca I, Ti I, Co I, Ni I, Rb I, Zr I, Ba II, La II and Cr I) for 16 solar-like stars with masses between 0:8 and 1:2 Mfi aproximatedly, including 10 planet-host stars detected by the CoRoT Space Mission. For this study, we use data from the ESO public archive: (i) high resolution spectra (R 47000) from the UVES spectrograph on the VLT/UT2-ESO (for 7 stars, covering the wavelength range 3450-4515 Å and 5500-9400 Å) and (ii) high resolution spectra from HARPS spectrograph on the La Silla-ESO 3.60 m telescope (for 9 stars, covering the wavelength range 4200-6865 Å). Our spectral analysis is based on MARCS models of atmosphere and Turbospectrum spectroscopic tools. On the base of the computed parameters, the referred abundances appears to follow the same behavior of the solar curve abundances. Further, one observes a signifficant correlation between the abundance ratio [m/Fe] and condensation temperature (Tc) of refractory elements (Tc > 900 K). The behavior of the projected rotational velocity (v sin i) versus the computed abundances [m/Fe] is also analyzed, presenting no clear trends. This study oers additional constraints to trace the evolutive history of solar-like stars with planets, including the search for chemical dierences between stars with and without transit planets and anomalies in the studied abundances

Áreas de transição rural e urbana em São Gonçalo do Amarante : elementos para delimitação no planejamento territorial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior