Estudo da corrosão no aço carbono 1020 protegido com óleo de coco saponificado: análise físico-química do comportamento químico do tensoativo

Corrosion inhibitors in solution are utilized to minimize processes from corrosion in steel. Of the present dissertation was evaluated the efficiency by inhibition from the surfactant saponified coconut oil (OCS) in the carbon steel 1020 through in linear polarization electrochemistry technique, well as, studied the process from adsorption through from the isotherms from Langmuir, Frumkin and Temkin. The corrosion current was determined through in Tafel extrapolation from the curves in the polarization, and then, was calculated the efficiency in the inhibitor to each concentration and temperature. Were studied four concentrations (12,5 ppm, 25 ppm, 50 ppm, and 75 ppm) in the inhibitor OCS and one in the NaCl salt (10.000 ppm) in six temperatures (301 K, 308 K, 313 K, 318 K, 323 K, and 328 K) in triplicate. By the results obtained observed that the technique applied can evaluated with rapidity and efficiency corrosion inhibitors. In relation to the isotherms, the than best appropriated was the in Langmuir and in the concentrations studied, the that obtained the best efficiency was the concentration of 75 ppm

Obtenção e Caracterização Físico-Química do Sistema Compósito PEG-TiO2

Hybrid systems formed from polymers and transition metals have now their physical and chemical properties extensively investigated for use in electronic devices. In this work, Titanium Dioxide (TiO2) from the precursor of titanium tetrabutoxide and the composite system Poly(Ethylene Glycol)-Titanium Dioxide (TiO2-PEG) were synthesized by sol-gel method. The PEG as acquired and TiO2 and composites powders were analyzed by X-Ray Diffraction (XRD), Spectroscopy in the Infrared region with Fourier transform (IRFT), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS). In the XRD analysis were observed in the TiO2 crystal faces of one of its polymorphs - anatase phase, crystal planes in Poly (Ethylene Glycol) with considerable intensity and in the composite systems the mixture of crystal faces of their precursors isolated and reduction of crystallinity. The TG / DTG suggested increasing the thermal instability of PEG in the composite powders as TiO2 is incorporated into the system. Spectral analysis presented in the infrared overlapping bands for the polymer and metal oxide, reducing the intensity of symmetric stretching of ligand groups in the main chain polymer and angular deformations; were observed using SEM micrographs of the morphological changes suffered by composite systems with the variation of the oxide concentration. Analyses by impedance spectroscopy indicated that the increased conductivity in composite occurs in line with the addition of the metal oxide concentration in the composite system

Obtenção e caracterização físico-química de blendas poliméricas, baseadas em POE e PMMA, dopadas com dióxido de titânio

The study of polymer blends has been an alternative method in the search field of new materials for obtaining materials with improved properties. In this work blends of poly(methyl methacrylate) (PMMA) and poly(ethylene oxide) (PEO) doped with titanium dioxide (TiO2) were studied. The PEO is a polymer semicrystalline structure varying between, 70 and 84% crystallinity, while the PMMA exhibits behavior amorphous in their structure. The use of TiO2 is related to corrosion-resistant of titanium as well as good heat transfer and other characteristics. The study of these polymer blends doped TiO2 gives the properties junction organic (polymer) and inorganic (oxide) which leads to modification of the properties of the resultant material. The blends were doped TiO2 (POE/PMMA/TiO2) in different proportions of the PMMA with the PEO and TiO2 fixed. The ratios were: 90/10/0,1; 85/15/0, 1; 80/20/0,1, 75/25/0,1 and 70/30/0,1. The resulting material was obtained in powder form and being characterized by Fourier Transformed Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Electrochemical Impedance Spectroscopy (EIS). The infrared spectra (IR) for the blends in different ratios showed a band at 1744 cm-1, characteristic of the C=O stretching, which increases in intensity with increasing PMMA composition, while in the spectrum of pure PEO this band is absent. This may suggest that the interaction is occurring between the polymers. In the micrographs of the blends also observed change in their surfaces with variation of the composition of PMMA, contributing to the change of the electrical properties of the material. The EIS data showed that the material exhibited conductivity of the order of 10-6 S.cm-1. The blend in the ratio B2(85/15/0, 1) showed better conductivity, σ = 1.56 x 10-6 S.cm-1. It was observed that the diffusion coefficient for the blends, B5(70/30/0, 1) was the largest, 1.07 x 10-6 m2.s-1. The XRD data showing that, with the variation in the composition of the PMMA blend crystallinity of the material is decreased reaching a minimum B3(80/20/0,1), and then increases again. Thermal analysis suggests that blends made from the material obtained can be applied at room temperature

Análises físico-químicas de polpas de frutas e avaliação dos seus padrões de identidade e qualidade

The pulps are products that add economic value enjoy the fruits of the surplus productions of the same. Have good market acceptance because of its practicality and diversity of flavors available year round. In order to assess the quality of the fruit pulp through the physical and chemical parameters and the characteristics of manufacturing industry, we analyzed 36 samples of frozen fruit pulp of three brands marketed in RIO Grande do Norte, 14 brand A, 12 of 10 brand B and brand C, which corresponded to 14 different flavors, of which 10 have identity Standards and Quality (ISQ S) established by the Ministério da Agricultura, Pecuária e Abastecimento (MAPA), totaling 27 samples with ISQ s. We conducted the following physicalchemical analyzes on samples of fruit pulp: Total solids, total soluble solids, pH, titratable acidity, total sugars and the determination of ascorbic acid. The percentage of failure for each parameter evaluated was 37, 04% in total soluble solids, 22,22% for total solids and titratable acidity, 7,40% in relation to pH. The total sugars were within the requirements demanded by the MAPA and ascorbic acid content, determined only in the pulp of acerola and cashew, presented a non compliance in the pulp of brand B. The percentage of failures of the pulps with ISQ S was 59% with brand A, B and C accounted for 3,70%, 33,33% and 22,22% respectively. The pulps which have no established atandards such as pineapple pulp, showed similar values between brands and literature data unlike the pulp of plum, jackfruit and tamarind which diverged greatly in parameters such as total solids and total soluble solids. The study demonstrates the need for greater quality control by the producers with respect to raw materials, processing, packing, stored and the importance of ISQ S to establish the flavors have not yet covered by existing legislation, but already highly commercialized

Confecção e caracterização físico-química de filmes compósitos autossustentáveis NaAlg-TiO2-WO3

A new self-sustainable film was prepared through the sol-gel modified method, previously employed in our research group; sodium alginate was used as the polymer matrix, along with plasticizer glycerol, doped with titanium dioxide (TiO2) and tungsten trioxide (WO3). By varying WO3 concentration (0,8, 1,6, 2,4 and 3,2 μmol) and keeping TiO2 concentration constant (059 mmol), it was possible to study the contribution of these oxides on the obtained films morphological and electrical properties. Self-sustainable films have analyzed by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XDR), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Electrochemical Impedance Spectroscopy (EIS). By the IR specters, it was possible identify the TiO2, and posteriorly WO3, addition has provided dislocation of alginate characteristics bands to smaller vibrations frequencies indicating an electrostatic interaction between the oxides and the polymer matrix. Diffractograms show predominance of the amorphous phase in the films. SEM, along with EDX, analysis revealed self-sustainable films showed surface with no cracks and relative dispersion of the oxides throughout the polymer matrix. From Impedance analysis, it was observe increasing WO3 concentration to 2,4 μmol provided a reduction of films resistive properties and consequent improvement of conductive properties

Obtenção de polímeros graftizados de quitosana e estudo das propriedades físico-químicas para aplicação na indústria do petróleo

Chitosan is a biopolymer derived from the shells of crustaceans, biodegradable, inexpensive and renewable with important physical and chemical properties. Moreover, the different modifications possible in its chemical structure generate new properties, making it an attractive polysaccharide owing to its range of potential applications. Polymers have been used in oil production operations. However, growing concern over environmental constraints has prompted oil industry to search for environmentally sustainable materials. As such, this study sought to obtain chitosan derivatives grafted with hydrophilic (poly(ethylene glycol), mPEG) and/or hydrophobic groups (n-dodecyl) via a simple (one-pot) method and evaluate their physicochemical properties as a function of varying pH using rheology, small-angle Xray scattering (SAXS), dynamic light scattering (DLS) and zeta potential. The chitosan derivatives were prepared using reductive alkylation under mild reaction conditions and the chemical structure of the polymers was characterized by nuclear magnetic resonance (1H NMR) and CHN elemental analysis. Considering a constant mPEG/Chitosan molar ratio on modification of chitosan, the solubility of the polymer across a wide pH range (acidic, neutral and basic) could only be improved when some of the amino groups were submitted to reacetylation using the one-pot method. Under these conditions, solubility is maintained even with the simultaneous insertion of n-dodecyl. On the other hand, the solubility of derivatives obtained only through mPEG incorporation using the traditional methodology, or with the ndodecyl group, was similar to that of its precursor. The hydrophilic group promoted decreased viscosity of the polymer solutions at 10 g/L in acid medium. However, at basic pH, both viscosity and thermal stability increased, as well as exhibited a pronounced pseudoplastic behavior, suggesting strong intermolecular associations in the alkaline medium. The SAXS results showed a polyelectrolyte behavior with the decrease in pH for the polymer systems. DLS analyses revealed that although the dilute polymer solutions at 1 g/L and pH 3 exhibited a high density of protonated amino groups along the polymer chain, the high degree of charge contributed significantly to aggregation, promoting increased particle size with the decrease in pH. Furthermore, the hydrophobic group also contributed to increasing the size of aggregates in solution at pH 3, whereas the hydrophilic group helped reduce their size across the entire pH range. Nevertheless, the nature of aggregation was dependent on the pH of the medium. Zeta potential results indicated that its values do not depend solely on the surface charge of the particle, but are also dependent on the net charge of the medium. In this study, water soluble associative polymers exhibit properties that can be of great interest in the petroleum industry

Avaliação das propriedades físico-químicas de sistemas a base de carboximetilcelulose e poli (N-isopropilacrilamida) em soluções aquosas para aplicação na indústria do petróleo

Sustainable development is a major challenge in the oil industry and has aroused growing interest in research to obtain materials from renewable sources. Carboxymethylcellulose (CMC) is a polysaccharide derived from cellulose and becomes attractive because it is water-soluble, renewable, biodegradable and inexpensive, as well as may be chemically modified to gain new properties. Among the derivatives of carboxymethylcellulose, systems have been developed to induce stimuli-responsive properties and extend the applicability of multiple-responsive materials. Although these new materials have been the subject of study, understanding of their physicochemical properties, such as viscosity, solubility and particle size as a function of pH and temperature, is still very limited. This study describes systems of physical blends and copolymers based on carboxymethylcellulose and poly (N-isopropylacrylamide) (PNIPAM), with different feed percentage compositions of the reaction (25CMC, 50CMC e 75CMC), in aqueous solution. The chemical structure of the polymers was investigated by infrared and CHN elementary analysis. The physical blends were analyzed by rheology and the copolymers by UV-visible spectroscopy, small-angle X-ray scattering (SAXS), dynamic light scattering (DLS) and zeta potential. CMC and copolymer were assessed as scale inhibitors of calcium carbonate (CaCO3) using dynamic tube blocking tests and chemical compatibility tests, as well as scanning electron microscopy (SEM). Thermothickening behavior was observed for the 50 % CMC_50 % PNIPAM and 25 % CMC_75 % PNIPAM physical blends in aqueous solution at concentrations of 6 and 2 g/L, respectively, depending on polymer concentration and composition. For the copolymers, the increase in temperature and amount of PNIPAM favored polymer-polymer interactions through hydrophobic groups, resulting in increased turbidity of polymer solutions. Particle size decreased with the rise in copolymer PNIPAM content as a function of pH (3-12), at 25 °C. Larger amounts of CMC result in a stronger effect of pH on particle size, indicating pH-responsive behavior. Thus, 25CMC was not affected by the change in pH, exhibiting similar behavior to PNIPAM. In addition, the presence of acidic or basic additives influenced particle size, which was smaller in the presence of the additives than in distilled water. The results of zeta potential also showed greater variation for polymers in distilled water than in the presence of acids and bases. The lower critical solution temperature (LCST) of PNIPAM determined by DLS corroborated the value obtained by UV-visible spectroscopy. SAXS data for PNIPAM and 50CMC indicated phase transition when the temperature increased from 32 to 34 °C. A reduction in or absence of electrostatic properties was observed as a function of increased PNIPAM in copolymer composition. Assessment of samples as scale inhibitors showed that CMC performed better than the copolymers. This was attributed to the higher charge density present in CMC. The SEM micrographs confirmed morphological changes in the CaCO3 crystals, demonstrating the scale inhibiting potential of these polymers

Impacto do trabalho em profissionais de Saúde Mental de serviços de saúde do município de Mossoró-RN, 2012

The Psychiatric Reform has brought profound changes in assistance to people affected by mental disorders and behavior. In this context, mental health workers have played decisive roles of great impact, acting driving the process. Objective: To evaluate the impact felt by working professionals, because of the daily work with people who have psychiatric disorders. Methodology: This is a search field, a quantitative approach, sectional, descriptive and applied. Data collection occurred through the Assessment Scale Impact of Working in Mental Health Services (IMPACT-BR) applied to mental health researchers city Mossoró - RN. Results: Participants in this study 87 professionals, mostly female married, which took charge of higher education, working on a single service, working in the area for more than six years, aged between 25 and 64 years. There were a low effect of overloading the professionals surveyed. Discussion: Our results corroborate findings in other surveys conducted previously, not identifying large impact load at work among professionals of mental health teams studied. Subscales studied the highest score was observed in measuring the impact of work on team functioning. It was observed that the greater age and duration of action, reduced the emotional impact at work, suggesting that the experience enhances safety in decisions made and the possibility of greater control over the demands of work. Final Thoughts: The work presented showed that the interactive relationships between professionals and users are not the causes of greatest impact in the workplace, although it revealed overload in relation to specific aspects such as: fear of being assaulted by a patient and the feeling of physical exhaustion the end of the workday. Further investigations should be conducted on this topic in order to contribute to the implementation of psychiatric reform proposed by advances both in terms of assistance to individuals and the quality of life in the work of the professionals involved

Trabalhadores por conta própria: O trabalho dos vendedores ambulantes da passarela do Natal shopping e do Via Direta

This study aid to understand the work conditions of street vendors located on the sidewalks of two malls in Brazil Northeast Natal / RN - Both malls Natal Shopping and Via Direta, to analyze their inclusion in the informal economy and to study the supposed autonomy provided by work as self-employment in its both aspects economic and social analyzing the importance on the condition of "masters of their own business" has for the street vendors, as an alternative to not submission to the figure of the boss, that represents the exploitation of one class over another. The theoretical and methodological aspects that support this study was aimed in discussion on the restructuring of production, considering its effects on the world of work, pointing to unemployment as one of the potencies element of excluded processes that exciting workers to engage in the informal market. Informality is presented as a survival strategy and as integrating part of the reproduction of capital. This research was conducted under a critical perspective, whish has been utilized quantitative and qualitative analyses. The results of this study format questions that provided during the research process the socio-economic characterization of workers, main cause of this study, and how street vendors expres their status of workers as self-employed for their work, and the perception that they have on their form of inclusion in the informal market.

A Central Única dos Trabalhadores (CUT) no embate das contrarreformas da previdência social: contraposição ou consenso?

The provident rights were results of intense fights in between the capital and work, claiming the interventions of the state for the creation of an ample social protection system. In Brazil the law, Providence Social mark, dated 1923, from then on, the advances and extensions were many, of this diverse categories of politics. Mean while, in the 1990 s, the Brazilian government adopted the examples of other developed countries, the new pattern that hinted the realization of substantial changes on the states purpose, the reached rights and the proper organization of working classes. For the Social Providence, the principal loses turned out in 1998 and 2003; respectively in FHC governments and Lula, with the realization of two counter reforms that restricted the provident rights and motivated the privatization of public providence. In the scenery, the CUT, one of the representative organizations from working classes, founded in 1983, that has always itself with changed direction, from fighting to negotiating. This inflection determined the proposition of the center before the offers of the counter reforms, of Social Providence. The present work has the objective to analyze the social politic content of the fights from Brazilian union movement in the period of the conquests and disassembled rights and, to analyze the proposition, acting and offers from CUT in the counter reform period from Providence in the Government FHC and Lula. To perform this study beyond the essential bibliographical revision to found and deepen the subject, we use, the documental search through the internet pages, resolutions, informations and others publications from CUT. Using CUT in the governments worked in an elegant way, the FHC government against-reforms, showed itself through diverse actions, even though they didn t have homogeneous inside, contrary the neoliberalists politicians from this government, also the offers and precaution changers. While during the reign of Lula it shoved itself priority negociative and propositive

Trabalho e saúde na sociedade capitalista: uma relação inversamente proporciona

It is a dissertation which has the Area of Concentration: Social Services, Vocational Training, Labour and Social Protection. Research Line: Social Services, Labor, Social Protection and Citizenship. Brings an approach to health and worker safety, approached on the organization of work in their processes of worker exploitation, analyzed from the critical perspective and all. Its central objective of uncovering how the organization of work affects the health of their workers, considering the working process in the capitalist mode of production, the health-disease relationship. Displays the worker, as determined by the work process, emphasizing, along the lines of capitalism, the consequences for the physical well-being, mental and social workers. To this end, we make a documentary and bibliographic research, whose point of analysis is based on the perspective of the centrality of work, recovering their sense of ontological Marx, through which the transformations are discussed in the working world, listed based on context productive restructuring of capital, which occurs along the imperialist stage of capitalist mode of production. It is problematized, though, worker health, analyzed from the wider definition of health as a field of public health, considering the work process in health-disease relationship. Finally, the research developed raised between 2006 and 2010, the Graduate Programs UFRN that address the range of issues studied in this dissertation. The scientific outputs are problematized as a way to reveal the theoretical trends (critical or conservative) which facilitate the thematic area

Avaliação do risco ocupacional de trabalhadores expostos a agrotóxicos no município de Touros/Rio grande do Norte

The use of pesticides is being used intensively with severe consequences for exposed farmers. This study aimed to describe the socioeconomic and health profiles of 60 farmers in the city of Touros / RN through the questionnaire recommended by: (International Commission for Protection against Environmental Mutagens and Carcinogens (ICPEMC). The analysis of these data allowed to prove the importance of knowledge about the socioeconomic and health profile of rural farmers as a way to understand the reality of this population, that is vulnerable to exposure due to the lack of knowledge and conditions. Aiming to analyze the frequency of micronucleus (MN) and other nuclear abnormalities in oral mucosa cells of 54 farmers that work in the city of Touros / RN it was applied the micronucleus test (MN) in oral mucosa. Our results showed an increased frequency of MN and other nuclear abnormalities related to the exposure and effects of pesticides on health. Based on the results, it is clear that farmers are using pesticide in the wrong way and compromising their health. A Cordel has been developed as a method to taking the results to the people affected by the pesticides. Therefore this study alerts to the need for profound changes in the social, cultural and health context to reduce health risks for both people and for the environment

Entre índios tremembé e trabalhadores rurais: historicidade, mobilização política e identidades plurais no Ceará

As pesquisas antropológicas brasileiras podem tratar de forma frequentemente estanque e separada, por um lado, grupos camponeses e, por outro lado, grupos étnicos, quais sejam, ‘índios’, ‘quilombolas’, etc. Contextos e situações que indicam pluralidade identitária costumam ser simplificados em sua caracterização etnográfica e da dimensão multifacetada de relações e redes sociais. Assim, discuto aqui os processos de mobilização étnico-política e de demanda territorial, sem perder de vista os processos de ressignificação cultural e construção identitária que se engendram a partir de um campo semântico da etnicidade. Abordo, então, certas situações étnicas Tremembé (estado do Ceará) que desestabilizam, embaralham e colocam em risco representações antropológicas sobre o ‘camponês’, o ‘regional’ e o ‘indígena

Treinamento da ginástica rítmica: reflexões estéticas

O texto tem como objetivo refletir sobre os componentes estéticos presentes no treinamento da ginástica rítmica (GR). Tendo a hermenêutica como método, apresenta reflexões a partir de descrições de cenas do vídeo do programa História do esporte, exibido em junho de 2003 pela ESPN Brasil, cujo teor se remete ao dia-a-dia da equipe brasileira de GR em treinamento para os Jogos Pan-americanos de Santo Domingo. Tendo como suporte tais reflexões, discute implicações pedagógicas do ponto de vista estético para o treinamento da GR no âmbito escolar, advindas do modelo de treinamento de alta performance e possíveis interfaces entre esses dois contextos, considerando a necessidade da crítica e do respeito às especificidades de ambos

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