First study on the thermo-solvatochromism in aqueous 1-(1-butyl)-3-methylimidazolium tetrafluoroborate: A comparison between the solvation by an ionic liquid and by aqueous alcohols

The thermo-solvatochrornic behaviors of 2,6-diphenyl-4-(2,4,6-triphenylpyridinium-1-yl) phenolate, RB; 2,6-dichloro-4-(2,4,6-triphenyloyridinium-1-yl) phenolate, WB; 2,6-dibromo-4-[(E)-2-(1-methylpyridinium-4-yl)ethenyl] phenolate, MePMBr(2); 2,6-dibromo-4-[(E)-2-(1-n-octylpyridinium-4-yl)ethenyl] phenolate, OcPMBr(2), have been investigated in binary mixtures of the ionic liquid, IL, 1-(1-butyl)-3-methylimidazolium tetrafluorborate, [BuMeIm][BF(4)], and water (W), in the temperature range from 10 to 60 degrees C. Plots of the empirical solvent polarities, ET (probe) in kcal mol(-1), versus the mole fraction of water in the binary mixture, chi(w) showed nonlinear, i.e., nonideal behavior. Solvation by these IL-W mixtures shows the following similarities to that by aqueous aliphatic alcohols: The same solvation model can be conveniently employed to treat the data obtained; it is based on the presence in the system-bulk medium and probe solvation shell of IL, W, and the ""complex"" solvent 1:1 IL-W. The origin of the nonideal solvation behavior appears to be the same, preferential solvation of the probe, in particular by the complex solvent. The strength of association of the IL-W complex, and the polarity of the IL are situated between the corresponding values of aqueous methanol and aqueous ethanol. Temperature increase causes a gradual desolvation of all probes employed. A difference between solvation by IL-W and aqueous alcohols is that probe-solvent hydrophobic interactions appear to play a minor role in case of the former mixture, probably because solvation is dominated by hydrogen-bonding and Coulombic interactions between the ions of the IL and the zwitterionic probes.

Regime político e participação do legislativo na determinação da taxa de câmbio de países que conviveram com elevada inflação e persistentes déficits em transações correntes: os casos de Argentina, Bolívia, Brasil, México e Peru entre 1970 e 1989

O objetivo deste artigo é verificar a influência de variáveis políticas na determinação da taxa de câmbio em quatro países latino-americanos que conviveram com elevada inflação e déficit em Transações Correntes nas décadas de setenta e oitenta. Estudos empíricos já haviam demonstrado a influência das eleições. Nenhum, porém, havia incorporado a estrutura de decisão do Executivo e Legislativo neste processo. Só foi possível incorporar o regime político (Autoritário/Democrático) e a divisão de poder no Legislativo de todos os países num modelo standard de taxa de câmbio porque utilizamos a técnica de painel. Obtivemos os seguintes resultados: países classificados como Autoritários apresentaram uma taxa de câmbio mais valorizada e Legislativos mais fragmentados apresentaram uma taxa de câmbio mais desvalorizada. Vimos este último resultado com desconfiança uma vez que, entre os países da amostra, o regime Autoritário era, em alguns casos, uma ditadura militar e o Legislativo pouco intervia nas decisões. Interagimos o regime político com fragmentação e percebemos que o efeito da classificação do regime predomina. No caso, se existir um regime Autoritário, o câmbio resultante da interação ainda será valorizado. A divisão de poder no Legislativo apenas provoca uma redução no impacto da valorização.

A metodologia do ensino superior e a sua significação para a formação do professor de ensino superior feita nos cursos de mestrado em educação

A formação dos docentes para o magistério superior é uma das funções dos Cursos de Mestrado. Na pesquisa das condições em que se desenvolve a formação do professor de Ensino Superior nos Cursos de Mestrado em Educação, identificam-se. entre outras disciplinas básicas, algumas especificamente didáticas: a Metodologia do Ensino Superior no IESAE/cMEd, a Didática do Ensino Superior na UFRJ/CMEd e a Metodologia Didática na PUC/CMEd. Verifica-se não serem obrigatórias essas disciplinas para todos os mestrandos, fato que leva a supor serem suas funções insuficientemente definidas na estrutura curricular desses Cursos, no tocante ã formação do docente. Julgando-se desempenharem essas disciplinas uma mesma função na formação do professor, precisamente daquele que se destina ao magistério superior, supõe-se que a falta de definição do papel por ela desempenhado no currículo dos mestrandos em Educação resulta da imprecisão dos termos Metodologia do Ensino Superior, Didática do Ensino Superior e Metodologia Didática. Esta imprecisão é constatada ao examinar-se a literatura especializada e ao analisar-se as respostas dos mestrandos que cursaram estas disciplinas e que as lecionaram. Os resultados das reflexões dos professores feitas conduziram a opção da Metodologia do Ensino Superior como disciplina eminentemente formativa do docente para este nível de ensino, por considerá-la mais abrangente do que as demais. Pelo mesmo motivo, defende-se sua obrigatoriedade de no currículo de todos os mestrandos em Educação. Caracteriza-se a MES pela interdisciplinar idade, definindo-a como método de trabalho reflexivo, tico e elaborativo que possibilita ao professor de Ensino Superior conduzir adequadamente o processo ensino-aprendizagem. o trabalho consta de duas etapas: a fundamentação teórica e a pesquisa de campo. Na primeira foram feitas: a revisão da literatura, a definição da função da Metodologia do Ensino Superior na formação dos professores e o estudo analítico dos programas das disciplinas Metodologia do Ensino Superior, Didática do Ensino Superior e Metodologia Didática. A pesquisa de campo consiste em aplicação de questionários e entrevistas. o universo da pesquisa compõe-se de todos os mestrandos que cursaram as disciplinas Metodologia de Ensino Superior, Didática do Ensino Superior e Metodologia Didática, dos professores destas disciplinas e dos Coordenadores dos Cursos de Mestrado em Educação do IESAE, da UFRJ e da PUC, respectivamente(1976). Os pressupostos e questionamentos que orientam a pesquisa referem-se à imprecisão conceitual da Metodologia do Ensino Superior e a seu papel indefinido na formação do professor de Ensino Superior.

Construção de um aparato experimental para monitoramento in situ da deposição de filmes finos de titânio por magnetron sputtering

The technique of surface coating using magnetron sputtering is one of the most widely used in the surface engineering, for its versatility in obtaining different films as well as in the micro / nanometric thickness control. Among the various process parameters, those related to the active species of the plasma are of the most fundamental importance in the mechanism and kinetics of deposition. In order to identify the active species of the plasma, parameters such as gas flow, pressure and density of electric power were varied during titanium coating on glass substrate. By flowing argon gas of 10, 20, 30, 40 and 50 sccm (cubic centimeters per minute) for each gas flow a sequential scan of the electric current of 0.10, 0.20, 0.30, 0.40 , 0.50 A. The maximum value of 0.50 A was chosen based both on literature data and on limitations of the equipment. The monitoring of plasma species present during the deposition was carried out in situ by the technique of optical emission spectroscopy (OES) through the spectrometer Ocean Optics USB2000 Series. For this purpose, an apparatus was developed to adapt the OES inside the plasma reactor to stay positioned closest to the target. The radiations emitted by the species were detected by an optical fiber placed behind the glass substrate and their intensities as a function of wavelength were, displayed on a monitor screen. The acquisition time for each condition of the plain parameters was related to the minima of spectral lines intensities due to the film formed on the substrate. The intensities of different emission lines of argon and titanium were then analyzed as a function of time, to determine the active species and estimate the thickness of the deposited films. After the deposition, the coated glasses thin films were characterized by optical transmittance through an infrared laser. It was found that the thickness and deposition rate determined by in situ analysis were consistent with the results obtained by laser transmittance

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 adsorvente obtido de terras diatomáceas para remoção de metais pesados em águas produzidas: processamento, caracterização e dinâmica em leito fixo

The acceleration of industrial growth in recent decades on all continents aroused the interest of the companies to counter the impacts produced on the environment, spurred primarily by major disasters in the petroleum industry. In this context, the water produced is responsible for the largest volume of effluent from the production and extraction of oil and natural gas. This effluent has in its composition some critical components such as inorganic salts, heavy metals (Fe, Cu, Zn, Pb, Cd, ), presence of oil and chemicals added in the various production processes. In response to impact, have been triggered by research alternative adsorbent materials for water treatment and water produced, in order to removing oils and acids and heavy metals. Many surveys of diatomaceous earth (diatomite) in Brazil involve studies on the physico-chemical, mineral deposits, extraction, processing and applications. The official estimated Jazi are around 2.5 million tonnes, the main located in the states of Bahia (44%) and Rio Grande do Norte (37,4%). Moreover, these two states appear as large offshore producers, earning a prominent role in research of adsorbents such as diatomite for treatment of water produced. Its main applications are as an agent of filtration, adsorption of oils and greases, industrial load and thermal insulator. The objective of this work was the processing and characterization of diatomite diatomaceous earth obtained from the municipality of Macaíba-RN (known locally as tabatinga) as a low cost regenerative adsorbent for removal of heavy metals in the application of water produced treatment. In this work we adopted a methodology for batch processing, practiced by small businesses located in producing regions of Brazil. The characterization was made by X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET). Research conducted showed that the improvement process used was effective for small volume production of diatomite concentrated. The diatomite obtained was treated by calcination at temperature of 900 oC for 2 hours, with and without fluxing Na2CO3 (4%), according to optimal results in the literature. Column adsorption experiments were conducted to percolation of the in nature, calcined and calcined fluxing diatomites. Effluent was used as a saline solution containing ions of Cu, Zn, Na, Ca and Mg simulating the composition of produced waters in the state of Rio Grande do Norte, Brazil. The breakthrough curves for simultaneous removal of copper ions and zinc as a result, 84.3% for calcined diatomite and diatomite with 97.3 % for fluxing. The calcined fluxing diatomite was more efficient permeability through the bed and removal of copper and zinc ions. The fresh diatomite had trouble with the permeability through the bed under the conditions tested, compared with the other obtained diatomite. The results are presented as promising for application in the petroleum industry

Caracterização de superfícies de titânio modificado por oxidação à plasma

Recent years have seen a significant growth in surface modifications in titanium implants, resulting in shorter healing times in regions with low bone density. Among the different techniques, subtraction by chemical agents to increase oxidation has been applied for surface treatment of dental implants. However, this technique is generally unable to remove undesirable oxides, formed spontaneously during machining of titanium parts, raising costs due to additional decontamination stages. In order to solve this problem, the present study used plasma as an energy source to both remove these oxides and oxidize the titanium surface. In this respect, Ti disks were treated by hollow cathode discharge, using a variable DC power supply and vacuum system. Samples were previously submitted to a cleaning process using an atmosphere of Ar, H2 and a mixture of both, for 20 and 60 min. The most efficient cleaning condition was used for oxidation in a mixture of argon (60%) and oxygen (40%) until reaching a pressure of 2.2 mbar for 60 min at 500°C. Surfaces were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), adhesion and cell proliferation. SEM showed less cell spreading and a larger number of projections orfilopodia in the treated samples compared to the control sample. AFM revealed surface defects in the treated samples, with varied geometry between peaks and valleys. Biological assays showed no significant difference in cell adhesion between treated surfaces and the control. With respect to cell proliferation, the treated surface exhibited improved performance when compared to the control sample. We concluded that the process was efficient in removing primary oxides as well as in oxidizing titanium surfaces

Diagnóstico de plasma de cátodo oco: análise da ação de plasma de argônio e Ar-H2 para a deposição de filmes finos de titânio em pós-descarga

Plasma DC hollow cathode has been used for film deposition by sputtering with release of neutral atoms from the cathode. The DC Plasma Ar-H2 hollow cathode currently used in the industry has proven to be effective in cleaning surfaces and thin film deposition when compared to argon plasma. When we wish to avoid the effects of ion bombardment on the substrate discharge, it uses the post-discharge region. Were generated by discharge plasma of argon and hydrogen hollow cathode deposition of thin films of titanium on glass substrate. The optical emission spectroscopy was used for the post-discharge diagnosis. The films formed were analyzed by mechanical profilometry technique. It was observed that in the spectrum of the excitation lines of argon occurred species. There are variations in the rate of deposition of titanium on the glass substrate for different process parameters such as deposition time, distance and discharge working gases. It was noted an increase in intensity of the lines of argon compared with the lines of titanium. Deposition with argon and hydrogen in glass sample observed a higher rate deposition of titanium as more closer the sample was in the discharge

Recuperação de fósforo por cristalização de estruvita

This study investigated the influence of the molar ratio, the phosphorus initial concentration, the mixture gradient, mixing time, pH and the secondary nucleation on struvite s crystallization in synthetic water in batch reactors. The study was divided into two stages. The first investigated struvite s crystallization at different Mg:N:P molar ratios and at different initial concentrations of magnesium, nitrogen and phosphorus. It was also evaluated the importance of secondary nucleation on the struvite s crystallization. In the second, five parameters were tested to evaluate their influence on the struvite s crystallization, which were: Mg:N:P molar ratio, initial concentration of phosphate, mixing time, mixture gradient and pH. The best conditions for struvite s crystallization were: Mg:N:P = 1,3:1:1 molar ratio; mixture gradient = 60 rpm, pH = 10.0, mixing time = 5 minutes and high initial concentrations of the constituent ions of struvite. Furthermore, the use of struvite crystals as seed influenced positively on the struvite s crystallization

Amorphous carbon nitrogenated films prepared by plasma immersion ion implantation and deposition

In this work, an investigation was conducted on amorphous hydrogenated-nitrogenated carbon films prepared by plasma immersion ion implantation and deposition. Glow discharge was excited by radiofrequency power (13.56 MHz, 40 W) whereas the substrate-holder was biased with 25 kV negative pulses. The films were deposited from benzene, nitrogen and argon mixtures. The proportion of nitrogen in the chamber feed (R-N) was varied against that of argon, while keeping the total pressure constant (1.3 Pa). From infrared reflectance-absorbance spectroscopy it was observed that the molecular structure of the benzene is not preserved in the film. Nitrogen was incorporated from the plasma while oxygen arose as a contaminant. X-ray photoelectron spectroscopy revealed that N/C and O/C atomic ratios change slightly with R-N. Water wettability decreased as the proportion of N in the gas phase increased while surface toughness underwent just small changes. Nanoindentation measurements showed that film deposition by means of ion bombardment was beneficial to the mechanical properties of the film-substrate interface. The intensity of the modifications correlates well with the degree of ion bombardment. (c) 2006 Elsevier B.V. All rights reserved.

Síntese, caracterização e aplicação de MCM-41 funcionalizado com diisopropilamina no processo de adsorção do dióxido de carbono

Emissions of CO2 in the atmosphere have increased successively by various mechanisms caused by human action, especially as fossil fuel combustion and industrial chemical processes. This leads to the increase in average temperature in the atmosphere, which we call global warming. The search for new technologies to minimize environmental impacts arising from this phenomenon has been investigated. The capture of CO2 is one of the alternatives that can help reduce emis ions of greenhouse gases. The CO2 can be captured through the process of selective adsorption using adsorbents for this purpose. Were synthesized by hydrothermal method, materials of the type MCM-41 and Al-MCM-41 in the molar ratio Si / Al equal to 50. The synthesis of gels were prepared from a source of silicon, sodium, water and aluminum in the case of Al-MCM-41. The period of synthesis of the materials was 5 days in autoclave at 100°C. After that time materials were filtered, washed and dried in greenhouse at 100 º C for 4 hours and then calcined at 450 º C. Then the calcined material was functionalized with the Di-isopropylamine (DIPA) by the method of wet impregnation. We used 0.5 g of material mesopores to 3.5 mL of DIPA. The materials were functionalized in a closed container for 24 hours, and after this period were dried at brackground temperature for 2 hours. Were subsequently subjected to heat treatment at 250°C for 1 hour. These materials were used for the adsorption of CO2 and were characterized by XRD, FT-IR, BET / BJH, SEM, EDX and TG / DTG. Tests of adsorption of CO2 was carried out under the following conditions: 100 mg of adsorbent, temperature of 75°C under flow of 100 mL/min of CO2 for 2 hours. The desorption of CO2 was carried out by thermogravimetry from ambient temperature to 900ºC under flow of 25 mL min of He and a ratio of 10ºC/min. The difratogramas X-ray for the synthesized samples showed the characteristic peaks of MCM-41, showing that the structure of it was obtained. For samples functionalized there was a decrease of the intensities of these peaks, with a consequent reduction in the structural ordering of the material. However, the structure was preserved mesopores. The adsorption tests showed that the functionalized MCM-41 is presented as a material promising adsorbent, for CO2 capture, with a loss of mass on the desorption CO2 of 7,52%, while that in Al-MCM- 41 functionalized showed no such loss

Determinação da composição química do molusco Anadara notabilis encontrado em Galinhos no Rio Grande do Norte

Given the large existing biodiversity in the Brazilian coast, where many species are still little known, even under the nutritional aspect, and considering that bivalve molluscs are constituted by a natural resource of well accepted by the population, chose the bivalve Anadara notabilis, it was not found in the literature any nutritional or toxicological information about it and because its size is much larger than other species of mollusks commonly found in this region. Were studied moisture, ash, protein, macro and micro minerals, and metal ions of toxicological significance. All analytical determinations followed the standards of the Institute Adolfo Lutz. The protein determination was performed by the Kjeldahl method. All metal ions were determined by optical emission spectroscopy with inductively coupled plasma (ICP-OES) method described by USEPA 6010C. The results showed that Anadara notabilis can be introduced into food for human beings, in view of its mineral wealth. Noteworthy among the macronutrients phosphorus and magnesium showed that their values in mg / kg 918.7 and 586.7. With regard to micronutrients stand out with this iron 586.7 mg / kg and zinc with 12.31 mg / kg. Was not found high content of metal contaminants to this mollusc, which would prevent their use, only this chromium 0.7 mg / kg above the value established by Brazilian legislation. The results will certainly be very useful in future studies of nutrition and to build a table of chemical composition of Brazilian foods

Espectrometria de emissão óptica com plasma indutivamente acoplado aliada à quimiometria na determinação de íons metálicos no molusco Mytella falcata para discriminação de estuários potiguares

This work examined the possibility of using mussel Mytella falcata as bioindicator sample to detect metal ions in several estuaries potiguares, since species substances that accumulate in their tissues due to its characteristics filter feeders have been used for environmental monitoring. The chemometrics by principal components analysis was used to reduce the size of the original data in order to establish a pattern of distribution of metal ion. Samples were collected at three different points in the estuaries Curimataú, Guaraíra-Papeba, Potengi, Galinhos-Guamaré and Piranhas-Assu having been marked with the location using GPS (Global Positioning System). The determination of humidity content and digestion of the samples were performed using methods described in the Compendium of analytical standards of the Institute Adofo Lutz (2005) and the determination of metal ions of the elements Al, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Sn and Zn were performed by optical emission spectrometry with inductively coupled plasma as described by USEPA method 6010C. The results show that it is possible to use this molluscum Mytella falcata in the estuaries of Rio Grande do Norte for the determination of metal ions. The data were subjected to principal components analysis (PCA) which enabled us to verify the distribution pattern of the metal ions studied in several estuaries potiguares and group them according to the metal ions in common with and relate them to the activities in each region

Phosphatidylcholine and Sphingomyelin Profiles Vary in Bos taurus indicus and Bos taurus taurus In Vitro- and In Vivo-Produced Blastocysts

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

Search for heavy Majorana neutrinos in mu(+/-)mu(+/-) + jets and e(+/-)e(+/-) + jets events in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)