Desevolvimento de nanocompósitos de poli(metacrilato de metila)/argila processados por mistura no estado fundido

Poly(methyl methacrylate)/clay nanocomposites were prepared by melt mixing using a montmorillonite-rich clay (MMT). The clay in natura was treated with acrylic acid to facilitate the dispersion in the polymer matrix. A masterbatch of PMMA/clay was prepared and combined with the pure PMMA and then subjected to extrusion process using singlescrew and twin-screw extruders followed by injection. Nanocomposites were processed with clay contents of 1, 3, 5 and 8 wt.%. The effect of shear processing on the morphology of the nanocomposites was evaluated by XRD, SEM and TEM. Thermal and mechanical properties of the nanocomposites were investigated through TGA, DSC, HDT, VICAT, tensile and impact tests, to evaluate the effect of the addition of clay to the PMMA matrix. Flammability tests were also conducted to investigate the effect of the addition of clay on the flame retardation properties. SEM images of the nanocomposites indicated the presence of clay agglomerates, which resulted in the reduction of properties such as thermal stability, mechanical strength and impact resistance, and increased the rate of burning for materials processed by both extrusion routes

Nacionalização do trabalho e constituição: análise das regras de nacionalização do trabalho à luz do princípio da isonomia

There is a clear relationship between citizenship and labor market. While foreign nationals are equal in dignity and rights in the laws governing the employment of this labor force. Motivated by reasons of state security or political direction, such laws to a greater or lesser degree, create establish a system of worker protection in the face of the foreign national. These rules have a direct impact on economic regulation, as they can affect the supply of skilled labor or not, articulating with the economic order envisaged by the 1988 Constitution. The Constitution adopts several principles in its economic order, so that the issues involving the rules of the nationalization of all work must be considered in a systematic way, one can not choose a pleasure interpreter. The nationalization of the work rules are not unique to Brazil, similar rules exist in several countries of South America and Africa. In Europe they already existed, but lost out on the basis of treaties setting up the European Union, although other mechanisms are used for the purpose of protecting the citizens of the member states, making policies equal treatment legislation symbolic. The nationalization of the work rules governing the relationship between nationality and the labor market and are in a legal category, which has a function to fulfill in the Brazilian legal system. Not all rules nationalization violate the principle of equality, as it is possible, depending on the circumstance indeed adopt a criterion that implies differentiation between nationals and foreigners. The Constitution has a will arising from its normative force, so that the assumptions it (constitution) used to discriminate may also be possible by ordinary legislation, since the situation is actually justifiably constitutional

Formação moral das crianças: construção de regras fundamentais aos valores do Movimento dos Trabalhadores Rurais Sem Terra (MST)

The acquiring process of morals on a person is one of the most important aspects of his Social Identity. The basis for his ethics and moral choices are built when he interacts with the world. A child that interacts with participants of Movimento Sem Terra (MST) movement that fights for the Land Reform and the transformation of the society may have the opportunities to acquire the culture, morals and ethics of this movement. Based on this understanding, this work intends to comprehend how children think and incorporate the rules that are the base of the values and principles of MST, considering the diversity of the situations, the limits and the possibilities to experience these values in their everyday life in the Movement. To understand how the process of cognitive construction of the rules takes place in a child, it is important to consider the theories of Jean Piaget. According to him, morals development follows a sequence: the anomie (0 to 2 years old), marked by the absence of rules; the heteronomy (2 to 6/7 years old), where takes place the adoption of rules due to exterior obedience, such as a relative, an institution or a movement; and the autonomy (from 6/7 years old on), in which rules are considered legitimate. All the children in this research have relatives working at MST. The research has two parts. We have first observed the behavior of three groups of children (beyond six years old) while they were involved on their normal activities (kindergarten) activities. On the second moment, we have interviewed 20 children (between 3 and 10 years old). We used flashcards containing scenes; we also told stories and asked moral questions involving the character s behavior. We have noticed the unilateral respect and extern coercion are between the definers of the moral decisions of a child. The empathy and the reduction of the egocentrism help seeing the situation of the point of view of other, although it doesn t mean that one is going to accept others point of view. In the taking decision of the child other factors are also considered such as the space of socialization (family, school). Though the children don t work or take part at MST activities, they have already opinions about involved people behaviors. The interaction with relatives and teachers is one of the most important aspects to encourage them elaborate moral understandings according to the ethics of this movement

Os jogos com regras na perspectiva do desenho universal: contribuições à educação matemática inclusiva

To think about a school that is for everyone has been a challenge for many people connected to education worldwide demanding from researchers of each level of knowledge an association to such effort. The study presented on this paper unites itself to the voices, movements and researches of these scholars, seeking to contribute on building possibilities on which mathematics can be thought and worked on schools in order for every student to learn, whether they have some sort of deficiency, disorders, syndromes or not. This essay has the goal to investigate the possibilities of inclusive pedagogical practices mediated by math games with rules, developed and used throughout the Universal Design perspective; a qualitative research took place with a collaborative methodology that involved managers, teachers and students from a public school situated on the city of Natal/Brazil. On the investigation math games with rules were developed and made according to the Universal Design concept, starting from initial studies which articulated theoretical groundings to the reality of school and the teacher s conceptions. After that, classes using these tools were planned collectively which oriented inclusive pedagogical practices of classes from the 1st to the 4th year of elementary school. Throughout the process many instruments such as: tape recording, video footages, notes from the researcher; the teachers and the students were used for constant work evaluation and also to record the research data. In the end, the data indicated effective contributions of the mediated pedagogical practices by games with rules under the perspective of Universal Design for Inclusive Mathematics Education

Estratégia de escalonamento de controladores PID baseado em regras Fuzzy para redes industriais foundation fieldbus usando blocos padrões

The main objective of work is to show procedures to implement intelligent control strategies. This strategies are based on fuzzy scheduling of PID controllers, by using only standard function blocks of this technology. Then, the standardization of Foundation Fieldbus is kept. It was developed an environment to do the necessary tests, it validates the propose. This environment is hybrid, it has a real module (the fieldbus) and a simulated module (the process), although the control signals and measurement are real. Then, it is possible to develop controllers projects. In this work, a fuzzy supervisor was developed to schedule a network of PID controller for a non-linear plant. Analyzing its performance results to the control and regulation problem

Análise estatística das emissões de CO e HC produzidas por gases da exaustão veicular oriundos de gasolina, GNV e mistura álcool/gasolina

The vehicles are the main mobile sources of carbon monoxide (CO) and unburned hydrocarbons (HC) released into the atmosphere. In the last years the increment of the fleet of vehicles in the municipal district of Natal-RN it is contributing to the increase of the emissions of those pollutants. The study consisted of a statistical analysis of the emissions of CO and HC of a composed sample for 384 vehicles with mechanization Gasoline/CNG or Alcohol/Gasoline/CNG of the municipal district of Natal-RN. The tests were accomplished in vehicles submitted to Vehicular Safety's Inspection, in the facilities of INSPETRANS, Organism of Vehicular Inspection. An partial gases analyzer allowed to measure, for each vehicle, the levels of CO and HC in two conditions of rotation of the motor (900 and 2500 rpm). The statistical analysis accomplished through the STATISTICA software revealed a sensitive reduction in the efficiency of the converters catalytic after 6 years of use with emission average it is of 0,78% of CO and 156 (ppm) of HC, Which represents approximately 4 (four) times the amount of CO and the double of HC in comparison with the newest vehicles. The result of a Student s t-test, suggests strongly that the average of the emissions of HC (152 ppm), at 900 rpm, is 40% larger than at 2500 rpm, for the motor without load. This result reveals that the efficiency of the catalytic conversion is limited kinetically in low engine speeds. The Study also ends that when comparing the emissions of CO and HC considering the influence of the fuels, it was verified that although the emissions of CO starting from CNG are 62% smaller than arising from the gasoline, there are not significant differences among the emissions of HC originating from of CNG and of the gasoline. In synthesis, the results place the current criteria of vehicular inspection, for exhaust gases, in doubt, leading the creation of emission limits of pollutant more rigorous, because the efficiency of the converters catalytic is sensibly reduced starting from 6 years of use. It is also raised the possibility of modifications in the test conditions adopted by the current norms, specifically in the speed engine, have seen that in the condition without load the largest emission indexes were registered in slow march. That fact that allows to suggest the dismissal of the tests in high speed engine, reducing the time of inspection in half and generating economy of fuel

Caracterização físico-química, reológica e sensorial de iogurte obtido pela mistura dos leites bubalino e caprino

Milk from different animals can be used for dairy production. Yoghurt is a popular fermented milk product and considered to be one of the greatest importance in terms of consumer acceptance and consumption. The present research deals with the production of strawberry set-type yoghurt by mixing goat and buffalo s milk and it has the objective of taking advantage of the intrinsic characteristics of each milk to produce a final product with desirable attributes. It was conducted by analyzing five experimental groups with different proportions of goat and buffalo s milk: C 100% goat s milk; 7C3B - 70% goat s milk and 30% buffalo s milk, 5C5B - 50% goat s milk and 50% buffalo s milk, 3C7B 30% goat s milk and 70% buffalo s milk; B - 100% buffalo s milk. Each group was evaluated for total solids content and the acidification profile was monitored every 30 minutes by pH analysis. The yoghurt samples were analyzed for physical-chemical (pH, acidity, protein, fat, total and reducing sugars, ash and total solids), rheological (syneresis and viscosity) and sensory characteristics (appearance, odor, consistency and flavour). Samples with higher percentual of bubaline milk reached Vm faster, but the time necessary for pH 4.6 (Te) were similar between groups. Statistical differences (p<0.05) were observed for fat and total solids content of yoghurt, with superior values for groups higher proportions of buffalo s milk. The parameters of behavior reached by the model of Ostwald of Waale pointed yoghurt samples as non-Newtonian and pseudoplastic fluids. Yoghurt made only with goat s milk (C) had higher values (p<0.05) for syneresis, which can be explained by its fragile coagulum. Additionally, this group also had the lowest sensory scores for the attributes consistence and taste, while bubaline yoghurt (B) obtained the best acceptance indexes for all of the appraised parameters

Comparação entre planejamento estatístico experimental e análise dimensional em operações de mistura e separação para sistema óleo-água

This work aims to determine a better methodology to help predicting some operational parameters to a new design of mixer-settler on treating wastewater produced by petroleum industry, called MDIF (Misturador-Decantador à Inversão de Fases/ Mixer-Settler based on Phase Inversion MSPI). The data from this research were obtained from the wastewater treatment unit, called MSPI-TU, installed on a wastewater treatment plant (WTP) of PETROBRAS/UO-RNCE. The importance in determining the better methodology to predict the results of separation and extraction efficiency of the equipment, contributes significantly to determine the optimum operating variables for the control of the unit. The study was based on a comparison among the experimental efficiency (E) obtained by operating MSPI-TU, the efficiency obtained by experimental design equation (Eplan) from the software Statistica Experimental Design® (version 7.0), and the other obtained from a modeling equation based on a dimensional analysis (Ecalc). The results shows that the experimental design equation gives a good prediction of the unit efficiencies with better data reliability, regarding to the condition before a run operation. The average deviation between the proposed by statistic planning model equation and experimental data was 0.13%. On the other hand, the efficiency calculated by the equation which represents the dimensional analysis, may result on important relative deviations (up 70%). Thus, the experimental design is confirmed as a reliable tool, with regard the experimental data processing of the MSPI-TU

Caracterização do comportamento geotécnico de mistura de resíduo de pneus e solo laterítico

A technological alternative for the correct disposal of tires is the use in the construction of embankment with soil and shredded tires. The use of waste tires in tropical soils requires prior knowledge of the properties and limitations of these materials. In this work, the results of an experimental program was devised to characterize the behavior of mixtures of waste tires and a lateritic soil. The residue used in this study is classified as tire buffings with an average size of 1.4 mm. The laboratory program included testing of particle size analysis, Atterberg limits, compaction, direct shear tests, permeability and confined compression tests with pure soil, pure tire and the mixtures. Proportions of 0% (pure soil), 10%, 20%, 40%, 50 % and 100% (pure tire) by weight were used. For the confining stress levels used in the study, the presence of tire residue provided a considerable increase in shear strength of the mixture. The maximum shear strength was obtained for a residue content of 40% by weight. Permeability tests on samples of waste under a confining stress of 100 kPa showed that the permeability increases significantly with increasing residue content until a residue content of 20%. The increase in permeability after that value showed to be negligible. Confined compression tests showed that the soil mixed with tire residue becomes more compressible than the pure soil. The secant constrained modulus (Msec) for the same vertical stress decreases with increasing percentage of residue.

Incorporação do lodo de tanque séptico como matéria-prima de uma mistura asfáltica

In Natal/RN, 68% of the population uses some kind of individual system for their domestic sewers treatment, being that the most used it is septic tank, followed by sumidouro. Every treatment system of sewers, usually used, generates a by-product denominated sludge. That residue presents some components, in its constitution, undesirable under the environmental and sanitary point of view. In such case, to assure that the system treatment has satisfactory results, it is necessary to do the adjusted disposition of the sludge sewage. Several countries are looking for technical alternatives for the use and disposition of residues. Under technical and environmental conditions appropriate, these materials can be used, decreasing the consumption of the natural resources and the treatment need, storage or elimination of the wastes, what decrease the risks created. Some of the alternatives of recycling of the sludge sewage are: the application in the agriculture, in the production of energy and as raw material in the civil construction. This study evaluated asphalt mixtures behavior that partially substituted conventional aggregates by septic tank sludge. The septic tank sludge gave origin to two raw materials called raw sludge and sludge ash. The raw sludge was put as a small aggregate and the sludge ash as filler. In the first experiment it was made a comparison between the mixture with conventional aggregates and the mixtures that replaced sand by raw sludge in the proportions from 5% to 40%. In the second experiment, it was made comparison between mixtures with 1%, 2% and 3% of sludge ash and cement. The stages developed along the study were: physical characterization of the conventional materials; physical, chemistry, thermal, mineralogical characterizations and analysis of environmental risk of the raw sludge; physical characterization and analysis of environmental risk of the sludge ash; analysis of the mixtures performance through its volumetric and mechanical characteristics; forecast of the mixtures susceptibility in the moisture presence. For the grain size composition used and with the percentage asphalt adopted, the mixtures with up to 7,5% of raw sludge in his composition attend to the National Department of Transports Infrastructure (DNIT) specifications. However, in agreement with the mixtures susceptibility in the moisture presence, the mixtures with addition of raw sludge don't present satisfactory acting. In such case, they could be used in arid and semi-arid areas. The raw sludge application in mixtures increased their voids volume and their stability. However, it damaged mixtures adhesiveness. Mixtures with sludge ash and with cement presented similar behavior. However, mixtures with sludge ash presented a better performance than mixtures with cement as for their stability and their tensile strength ratio. The mixture with 1% of sludge ash is better. The wastes studied don't represent environmental risk

Estudos de sinterização da mistura de pós cerâmicos diatomita-titânia

This work is part of an effort of consolidation of a daily search for powder technology at the Department of Physics of the Universidade Federal do Rio Grande do Norte. This work objective the study and development of new ceramic materials from raw materials abundant at the region. For this, were studied ceramic mixtures of powders from diatomite-titania to aiming at a new ceramic material from powder technology. The experimental work involved a characterization of ceramic powders from a diatomite-titania mixture. The powders obtained were pressed and then parameters like variation of mass, linear shrinkage, activation energy and the mechanism of sintering are studied in function of the time and temperature of sintering, beyond microstructural analysis. The obtained results allow us estimate the optimizing of sintering conditions of this material

Estudo da viabilização do uso da mistura híbrida ferrocarbonila / ferrita de NI0,5Zn0,5Fe2o4 como material absorvedor de radiação eletromagnética

Were synthesized ferrites of NiZn on systems Ni0,5Zn0,5Fe2O4, the precursors citrate method. The decomposition of the precursors was studied by thermogravimetric analysis and spectroscopy in the infrared region, the temperature of 350°C/3h. The evolution of the phases formed after calcinations at 350ºC/3h, 600, 1000 and 1100ºC/2h was accompanied by X-ray diffraction using the Rietveld refinement method for better identification os structures formed. Was observed for samples calcined at different temperatures increased crystallinity with increasing calcination temperature, being observed for the samples calcined at 900 and 1100 º C/2h was the precipitation of a secondary phase, the phase hematite. The ferrocarbonila of industrial origin was analyzed by X-ray diffraction and Rietveld for the identification of its structure. The carbonyl iron was added NiZn ferrite calcined at 350ºC/3h, 600, 900, 1000 and 1100ºC/2h to the formation of hybrid mixtures. They were then analyzed by Xray diffraction and Rietveld. The NiZn ferrite and ferrocarbonila as well as the hybrid mixtures were subjected to analysis of scanning electron microscopy, magnetic measurements and reflectivity. The magnetic measurements indicated that the ferrite, the ferrocarbonila, as well as hybrid mixtures showed characteristics of soft magnetic material. The addition of ferrocarbonila in all compositions showed an increase in the results of magnetic measurements and reflectivity. Best result was observed in the increase of the magnetization for the hybrid mixture of Ferrocarbonila / ferrite of NiZn calcined at 600ºC/2h. The mixture Ferrocarbonila / ferrite calcined 1000°C/2h presented better absorption of electromagnetic radiation in the microwave

Estudo da mistura comercial dolomita-quartzo, dopada com Hg(I), Cd(II) e Cr(III), para adsorção de H2S

The present work was to carry out a study on the adsorption of hydrogen sulfide (H2S) in arrays synthesized from a commercial clay mineral formed by a mixture of dolomite and quartz. To produce the ion exchange matrix were made using aqueous solutions of salts of cobalt II chloride hexahydrate (CoCl2.6H2O) II cadmium nitrate tetrahydrate (Cd (NO3)2.4H2O) I mercuric chloride (HgCl) nitrate and chromium III pentahydrate (Cr (NO3)3.5H2O). The arrays were subjected to hydrogen sulphide gas passage for one hour. To check the amount of gas adsorbed was used gravimetric process. The best result was in the adsorption matrix doped with cadmium and the solution retained for a longer time than the largest amount of H2S was the cobalt matrix. The matrix unmodified exhibited poor adsorption capacity. The characterization of the matrices were used XRD, XRF and IV. Mother with cadmium showed a high capacity in ion exchange, because the percentage of cadmium increased from 0% to 81.38% by replacing atoms of calcium and silicon which increased from 96.54% to 17.56% and 15, 72% to 0.32%, respectively, but also the best performance in adsorption of H2S adsorbing 11.89507 mg per gram of matrix

Uma abordagem para a verificação do comportamento excepcional a partir de regras de designe e testes

Checking the conformity between implementation and design rules in a system is an important activity to try to ensure that no degradation occurs between architectural patterns defined for the system and what is actually implemented in the source code. Especially in the case of systems which require a high level of reliability is important to define specific design rules for exceptional behavior. Such rules describe how exceptions should flow through the system by defining what elements are responsible for catching exceptions thrown by other system elements. However, current approaches to automatically check design rules do not provide suitable mechanisms to define and verify design rules related to the exception handling policy of applications. This paper proposes a practical approach to preserve the exceptional behavior of an application or family of applications, based on the definition and runtime automatic checking of design rules for exception handling of systems developed in Java or AspectJ. To support this approach was developed, in the context of this work, a tool called VITTAE (Verification and Information Tool to Analyze Exceptions) that extends the JUnit framework and allows automating test activities to exceptional design rules. We conducted a case study with the primary objective of evaluating the effectiveness of the proposed approach on a software product line. Besides this, an experiment was conducted that aimed to realize a comparative analysis between the proposed approach and an approach based on a tool called JUnitE, which also proposes to test the exception handling code using JUnit tests. The results showed how the exception handling design rules evolve along different versions of a system and that VITTAE can aid in the detection of defects in exception handling code

Geração de processos WS-BPEL com base em um algoritmo de reescrita de regras

Web services are computational solutions designed according to the principles of Service Oriented Computing. Web services can be built upon pre-existing services available on the Internet by using composition languages. We propose a method to generate WS-BPEL processes from abstract specifications provided with high-level control-flow information. The proposed method allows the composition designer to concentrate on high-level specifi- cations, in order to increase productivity and generate specifications that are independent of specific web services. We consider service orchestrations, that is compositions where a central process coordinates all the operations of the application. The process of generating compositions is based on a rule rewriting algorithm, which has been extended to support basic control-flow information.We created a prototype of the extended refinement method and performed experiments over simple case studies