Equilíbrio líquido-líquido para o sistema biodiesel de óleo de semente de melão (Cucumis melo l.) + metanol + glicerina

Rio Grande do Norte, northeast state from Brazil, it is the greatest producer and exporter of yellow melon, well known as Spanish melon. Despite the consumption of this fruit to be mainly its pulp, melon seeds are an important source of lipids considered an industrial residue it has been discharge product. The use of oilseeds in order to produce biodiesel establishes an important raw material and the increase of its production promotes the national development of the agriculture. In this background, the aim of this work has been to use oil from seeds of yellow melon to produce biodiesel and to accomplish a study of the phase equilibrium of the system evolving biodiesel, methanol and glycerin. The biodiesel was obtained by oil transesterification through methylic route with molar ratio 1:9.7 (oil:alcohol) and with a mass of NaOH of 0.5% from the oil mass; the reaction time was 73 minutes at 55 °C. A yield of 84.94% in biodiesel was achieved. The equilibria data present a well-characterized behavior with a great region of two phases. The tie lines indicate that methanol has a best solubility in the phase that is rich in glycerin. Consistency of the experimental data was made based on Othmer-Tobias and Hand correlations which values above 0.99 were found to correlation coefficients, this fact confers a good thermodynamic consistency to the experimental data. NRTL and UNIQUAC models were employed to predict liquid-liquid equilibrium of this system. It was observed a better concordance of the results when NRTL was applied (standard deviation 1.25%) although the UNIQUAC model has presented a quite satisfactory result either (standard deviation 2.70%). The NRTL and UNIQUAC models were also used to evaluate the effect of temperature in the range of 328 K to 358 K, in which a little change in solubility with respect to the data obtained at 298 K was observed, thus being considered negligible the effect of temperature

Equilíbrio líquido-líquido de sistemas aquosos com tensoativos polietoxilados: dados experimentais e modelagem

The nonionic surfactants when in aqueous solution, have the property of separating into two phases, one called diluted phase, with low concentration of surfactant, and the other one rich in surfactants called coacervate. The application of this kind of surfactant in extraction processes from aqueous solutions has been increasing over time, which implies the need for knowledge of the thermodynamic properties of these surfactants. In this study were determined the cloud point of polyethoxylated surfactants from nonilphenolpolietoxylated family (9,5 , 10 , 11, 12 and 13), the family from octilphenolpolietoxylated (10 e 11) and polyethoxylated lauryl alcohol (6 , 7, 8 and 9) varying the degree of ethoxylation. The method used to determine the cloud point was the observation of the turbidity of the solution heating to a ramp of 0.1 ° C / minute and for the pressure studies was used a cell high-pressure maximum ( 300 bar). Through the experimental data of the studied surfactants were used to the Flory - Huggins models, UNIQUAC and NRTL to describe the curves of cloud point, and it was studied the influence of NaCl concentration and pressure of the systems in the cloud point. This last parameter is important for the processes of oil recovery in which surfactant in solution are used in high pressures. While the effect of NaCl allows obtaining cloud points for temperatures closer to the room temperature, it is possible to use in processes without temperature control. The numerical method used to adjust the parameters was the Levenberg - Marquardt. For the model Flory- Huggins parameter settings were determined as enthalpy of the mixing, mixing entropy and the number of aggregations. For the UNIQUAC and NRTL models were adjusted interaction parameters aij using a quadratic dependence with temperature. The parameters obtained had good adjust to the experimental data RSMD < 0.3 %. The results showed that both, ethoxylation degree and pressure increase the cloudy points, whereas the NaCl decrease

Determinação de Dados de Equilíbrio Líquido-Vapor para Sistemas Hidrocarbonetos e Desenvolvimento de uma Nova Célula Dinâmica

In the present work are established initially the fundamental relationships of thermodynamics that govern the equilibrium between phases, the models used for the description of the behavior non ideal of the liquid and vapor phases in conditions of low pressures. This work seeks the determination of vapor-liquid equilibrium (VLE) data for a series of multicomponents mixtures of saturated aliphatic hydrocarbons, prepared synthetically starting from substances with analytical degree and the development of a new dynamic cell with circulation of the vapor phase. The apparatus and experimental procedures developed are described and applied for the determination of VLE data. VLE isobarics data were obtained through a Fischer's ebulliometer of circulation of both phases, for the systems pentane + dodecane, heptane + dodecane and decane + dodecane. Using the two new dynamic cells especially projected, of easy operation and low cost, with circulation of the vapor phase, data for the systems heptane + decane + dodecane, acetone + water, tween 20 + dodecane, phenol + water and distillation curves of a gasoline without addictive were measured. Compositions of the equilibrium phases were found by densimetry, chromatography, and total organic carbon analyzer. Calibration curves of density versus composition were prepared from synthetic mixtures and the behavior excess volumes were evaluated. The VLE data obtained experimentally for the hydrocarbon and aqueous systems were submitted to the test of thermodynamic consistency, as well as the obtained from the literature data for another binary systems, mainly in the bank DDB (Dortmund Data Bank), where the Gibbs-Duhem equation is used obtaining a satisfactory data base. The results of the thermodynamic consistency tests for the binary and ternary systems were evaluated in terms of deviations for applications such as model development. Later, those groups of data (tested and approved) were used in the KijPoly program for the determination of the binary kij parameters of the cubic equations of state original Peng-Robinson and with the expanded alpha function. These obtained parameters can be applied for simulation of the reservoirs petroleum conditions and of the several distillation processes found in the petrochemistry industry, through simulators. The two designed dynamic cells used equipments of national technology for the determination Humberto Neves Maia de Oliveira Tese de Doutorado PPGEQ/PRH-ANP 14/UFRN of VLE data were well succeed, demonstrating efficiency and low cost. Multicomponents systems, mixtures of components of different molecular weights and also diluted solutions may be studied in these developed VLE cells

Investigação histórica na formação de professores de matemática: um estudo centrado no conceito de função

In this study we analyzed the development of a teaching experience, involving students with a bachelor s degree in mathematics from UFRN, based on the history of mathematics and mathematical investigations with the aim of contributing to the improvement of the teaching-learning of mathematics. The historical investigation tasks were planned and applied in the classroom, focusing on functional thought. The results obtained during the experience were described and evaluated based on authors who support the assumption of investigation and history as an alternative to the learning of mathematics. We emphasize that the material of analysis consisted of a work diary, audio recordings, questionnaires with testimony of the students involved, and, in addition, the assessment of the teacher of that subject. With regard to the mathematical content, the study was restricted to the concept of function, forms of representation and notation. It was evident that students showed great improvement with regard to the necessary formalization of the mathematical contents which were focused on, and to the active involvement of the students at different stages of the study. We can affirm that the completed study certainly represents significant contributions to an approach in the teaching-learning of functional thought

O uso pedagógico de uma seqüência didática para a aquisição de algumas idéias relacionadas ao conceito de números complexos

The aim of the present work is to contribute to the teaching-learning process in Mathematics through an alternative which tries to motivate the student so that he/she will learn the basic concepts of Complex Numbers and realize that they are not pointless. Therefore, this work s general objective is to construct a didactic sequence which contains structured activities that intends to build up, in each student s thought, the concept of Complex Numbers. The didactic sequence is initially based on a review of the main historical aspects which begot the construction of those numbers. Based on these aspects, and the theories of Richard Skemp, was elaborated a sequence of structured activities linked with Maths history, having the solution of quadratic equations as a main starting point. This should make learning more accessible, because this concept permeates the students previous work and, thus, they should be more familiar with it. The methodological intervention began with the application of that sequence of activities with grade students in public schools who did not yet know the concept of Complex Numbers. It was performed in three phases: a draft study, a draft study II and the final study. Each phase was applied in a different institution, where the classes were randomly divided into groups and each group would discuss and write down the concepts they had developed about Complex Numbers. We also use of another instrument of analysis which consisted of a recorded interview of a semi-structured type, trying to find out the ways the students thought in order to construct their own concepts, i.e. the solutions of the previous activity. Their ideas about Complex Numbers were categorized according to their similarities and then analyzed. The results of the analysis show that the concepts constructed by the students were pertinent and that they complemented each other this supports the conclusion that the use of structured activities is an efficient alternative for the teaching of mathematics

Atribuição de significado ao conceito de proporcionalidade: contribuições da história da matemática

This study is the result of a work which approaches the Mathematics History how source of the meaning s attribution in the proportionality concept. We adopt the methodology of the source qualitative and we work with a group of teachers from instruction s public system of the fundamental and medium level from Pocinhos City Paraíba. For the data collection, we use the field notes, the questionnaire, a sequence of activities and the interview semistructured like instruments. The study had how objective to know the significates attributeds to proportionality concept through of the activity mediate from Mathematics History, besides to investigate if a approach of the nature enables modification according to this sense. The results obtaineds though the data analysis indicate that the activities bring contributions which refer to achieve objectives. On the other hand they also showed that we have a long trajectory to be trailed in the meaning of to turn the Mathematics History a subsidy effective in the teachers practice, in view of the formation absence in the knowledge area, besides the necessity of the approach adequated of the Mathematics History in the didatics books of Mathematic

Proposta para uma abordagem do conceito de oxirredução no Programa Nacional de Integração da Educação Profissional com a Educação Básica na modalidade de Educação de Jovens e Adultos Educação Profissional Técnica de Nível Médio (PROEJA)

The National Program of Professional Education Integration with Basic Education for Youngsters and Adults (PROEJA) Technical Professional Education Ensino Médio has opened a new chapter in the history of education in Brazil, making possible the integration of basic education and professional education. This new form of education, which is still in its early implementation, presents a series of challenges to be overcome. Specifically about the teaching of Chemistry, didactic material to match PROEJA s specific needs is practically inexistent. Thus, this work has the purpose of developing didactic material for the teaching of Chemistry for Professional and Technological Education of Youngsters and Adults in the courses of Electronics, Technical Electronics and Maintenance and Support for Computing at Instituto Federal de Educação,Ciência e Tecnologia do Rio Grande do Norte. This material aims at working chemical concepts of oxi-reduction reactions through a theme approach following Freire s conceptions for the teaching of Youngsters and Adults

Capacitação no Programa de Saúde da Família: divergências sobre o conceito de visita domiciliar nas equipes de Presidente Epitácio, São Paulo

O Programa de Saúde da Família (PSF) tem por intenção - e mérito - mudar o foco da atenção à saúde centrada no médico e na cura das doenças, para uma atenção centrada na promoção da saúde e prevenção de doenças por meio de uma equipe multidisciplinar. Para atingir esse objetivo, tem na prática de trabalho da visita domiciliar um dos instrumentos fundamentais para o entendimento da totalidade dos condicionantes que afetam a vida do cidadão. Neste artigo, discutem-se os conceitos de visita domiciliar com que operam as três principais categorias de trabalhadores do PSF - médicos, enfermeiros e agentes comunitários - , assim como sua relação com a formação no curso básico. A metodologia se baseia na técnica do discurso do sujeito coletivo a partir das entrevistas aplicadas. Concluímos que a falta de uniformidade sobre o conceito de visita domiciliar pode interferir na proposta de mudança do modelo de atenção à saúde. O artigo tece ainda considerações sobre as distintas concepções de visita domiciliar e sua relação com a organização do trabalho no interior das equipes.

Desenvolvimento de sistemas líquido-cristalinos empregando silicone fluido de co-polímero glicol e poliéter funcional siloxano

DEVELOPMENT of LIQUID-CRYSTALLINE SYSTEMS USING SILICON GLYCOL COPOLYMER and POLYETHER FUNCTIONAL SILOXANE. For the construction of the phase diagrams, the method of the aqueous titration was used. There were prepared 5 ternary diagrams, varying the surfactant and the oil phase. The liquid-crystalline phases were identified by polarized light microscopy. The formulations prepared with silicon glycol copolymer, polyether functional siloxane (PFS) and water (S(1)) and with diisopropyl adipate, PFS and water (S(4)) presented liquid-crystalline phases with lamellar arrangement. Moreover, after 15 days in hot oven (37 degrees C), the formulations presented hexagonal arrangement, evidencing the influence of the temperature in the organization of the system.

Foucault e a (bio) política: possibilidades e metamorfose de um conceito

The fundamental question developed in this research is to consider the possible meanings of biopolitics in the thought of Michel Foucault. In the first chapter of this study seeks to examine the rationality of biopower. It is able to show the rationality of acting as a social machinery for the manufacture of the subjectivity of individuals, biopolitics as a producer of bodies and subjectivity. The theme of biopolitics appears as inspiration of Nietzsche's metaphor of war. The idea that history is the war for dominance of the bodies. In the second chapter, the (bio) political will and political thought of resistance, fighting criticism as an attitude of revolt of the subject before his condition subjugated. The biopolitical here is intended as a conceptual tool for reading the thought / Foucault's work. A resistance that can be thought of as a biopolitical as a "refractoriness reflected". The third chapter will seek to show how the Foucault argues that power was already present the ethics of self-care. If the subject is a product, is captured by the discourse of biopower that manufactures its subjectivity, self care, it's time to think about the inner contents. Self care is something that offers resistance, as a possibility to think that these contents are constructed historically, and that therefore it is possible to reestablish the self-care is a policy of fighting these sedimented content that promotes colonization of the subjects. You can move from ruler to ruled itself, although this pursuit of liberty is always unfinished, always be a tension, a desire for freedom that can be undertaken not as a state, but at least the minimum and temporarily in other forms of existence, and other ways of relating, other ways of sociability, friendship, sexuality

O conceito de liberdade em o ser e o nada de Jean-Paul Sartre

This dissertation aims to address the concept of freedom from the perspective of the French philosopher Jean-Paul Sartre with reference to the main work Being and Nothingness. After presenting the concept of freedom we will try to show that it is related to the notion of responsibility, which will lead, ultimately, to define the Sartrean philosophy as a philosophy of action. In the first chapter we will present in passing the phenomenology of Edmund Husserl, philosopher from which Sartre will develop his concept of freedom. The Husserlian notion of consciousness (intentionality) is the way to develop his analysis of Sartre phenomenon of being. From this analysis Sartre submits their concepts of being in-itself and being for-itself. Being initself is defined as the things of the world devoid of consciousness, are the things that surround us. The In-itself has as its main brand positivity: it is what it is, is all that can be said about him. In turn being For-itself is the very being of man, which differs radically from the In-itself. The For-itself has as its main intentionality, ie, its ability to project outside itself in existence. That's when Sartre shows that this type of being realizes its existence on the basis of a constant nihilation. Here comes the notion of anything. Among the relations of the For-itself with the surrounding world stands a very special: relationship between consciousnesses. It is when we discuss the issue of another. Intersubjectivity, through sartrean analysis of look, show that the For-itself assumes a new existential dimension: the being-for others. That's when Sartre will emphasize his notion of conflict. The conflict in intersubjectivity would come from the fact that you want to take another- For-itself as an object. Given this we will analyze what Sartre called the concrete relations with others. The philosopher submit such relations in the form of ducts and conduits assimilation of ownership. In the first my-self to try to "get lost" in the consciousness of another, ownership of my conduct in-itself tries to "take ownership" of the subjectivity of the other and try to treat others as things, as objects. In this sense Sartre examines the experiences of love, masochism, indifference, desire and sadism. Following this route we will enter the land of freedom itself, which is the major theme of our work. Since Sartre defines the For-itself as a being that is projected to create your way of being, it can only define it as freedom. The freedom of the For-itself is taken in terms of autonomy of choice. Once the For-itself has no way of being a thing as being in-itself, it just may be picking up, that is, making your being. Here Sartre speaks of the anguish that would be the symptom of freedom itself. The fact that the For-itself have to choose on whether the call as one being distressed. However, in most cases the For-itself tries to escape from the anguish of freedom and takes refuge in bad faith. After setting the man (For-itself) as freedom Sartre defends that he is totally responsible for what he does of himself. Once the philosopher holds that man is not predetermined, ie, does not have an a priori essence, his philosophy has as its basic assumption the action. If Sartre argues that the For-itself must constantly choose your way of being, the action is the basis on which man will exercise his own freedom. In this sense we conclude the work with an approach to work Existentialism is a Humanism, which represent the entry of the philosopher on the practical aspects of life

O conceito de participação em João Escoto Eriúgena

This thesis aims at studying the concept of participation according to John Scotus Eriugena. The development of our research is based on an identification of Eriugena s sources, investigating the concept of participation since Dyonisus and the Greek Christian fathers, until the Periphyseon. To Eriúgena, the terms that are brought together in participation God, causes, and effects are, while everything that falls out of participation is not. Leaning on his understanding of the relation between cause and effect, according to which the effects participate in the cause and somehow are contained in it, he told us that all things and beings subsist eternally in God, and that God can signify Himself through the created things and beings. To Eriugena, creatures exist because they participate in the Divine Nature and receive their being from It, for nothing truly exists outside of It.

O conceito de consciência em o ser e o nada de J.-P. Sartre

This current discourse intends to prove how consciousness or Being-for-itself presents the idea that in its operation one can emphasize that it s Nothingness, transience and liberty in Jean-Paul Sartre s work O Ser e o Nada. To testify the proposed idea, the conception that Sartre gives to consciousness, representing nothingness, without any content that is connected to the possessor objects of a transphenomenal existence will be the starting point. This way, consciousness will be analyzed transcendently to the object that it s not, demonstrating its revealer-revealed condition, because it unveils a concrete world that exists against its idea, functioning as the revealer intentionality that there are beings instead of nothingness, obeying the ontological proof defended by Sartre. From this idea, every kind of consciousness will always be consciousness of something, a glance of the world, avoiding the fact that the consciousness could be considered nothing in the world. In order to live its original negation state of the world, apprehending this same world, with the purpose of a knowledge, it needs to be divided in two: the first degree consciousness or previous-reflexive cogito, that turns the proper reflexion possible, because, it s the consciousness proper transphenomenality of being different of all that connected to its existence being only its consequence; and the cogito, responsible to the positioning of the first degree consciousness, while aware of its own consciousness, that is, while being certain that knows. From this point, the way to untangle the consciousness or Being-for-itself will be developed as being Chasm, Liberty and transience. From this idea, it s intended to know how consciousness, that in Sartre s thoughts is originally nothing, could turn into Liberty that is presented in the field of transience? In other words, how these three internal structures imbricate one another to form consciousness in Sartre? First of all, it has to be considered the review of a conduct of human reality, the inquiry, that will be possible to understand how Nothingness exists as the mold of all kind of negation. After this, it will be shown, considering its way of existence, the human reality that is connected to Para-si, determined like nothingness, still is proposed like Liberty. Form this point, it will be possible to gleam how Liberty is lived deeply by Para-si in the shape of chasm, trying to how Para-si turns into nothingness, creating a chasm based on its proper liberty. Then, Liberty will be the proper mechanism used by Para-si to modificate its original chasm. The way Being-for-itself has to build to gain its goal will be projecting in transience, the building of something possible that brings one being back. However, will be demonstrated like Chasm can occupy the moment of a choice turning the decision instant an anguish stage, based on the failing of stability of the Being-for-itself, once nothingness persists in the field of the possibilities that human beings preserves in its essence while being essentially Liberty. From this idea, anguish will be studied as the proper consciousness of Liberty, being bad-faith the attempt of avoid Liberty trying to gain a shelter contradicting the fact that life is done of continual choices

Pareamento BCS em um Líquido de Luttinger em 1D

In this work we investigate the effect of a BCS-type pairing term for free spinless fermions, with a propensity to form a condensate of pairs in a 1+1 dimension. Using the of bosonization technique we explore the possible condition of existence of quasiparticles in a superconducting state. Although there is no spontaneous breaking of chiral symmetry the propagator of one-particle fermion is massive and, in fact, resembles the one-particle Green s function of conventional quasiparticles

Algumas considerações sobre o ensino e a aprendizagem do conceito de energia

Neste artigo procuramos abordar alguns aspectos relevantes sobre o ensino e a aprendizagem do conceito de energia, tais como as concepções de energia do senso comum e as relações entre transformações de energia e meio ambiente, bem como destacar a viabilidade da utilização de textos com abordagens históricas e, finalmente, analisamos um texto interdisciplinar que relaciona energia e meio ambiente. Com relação ao referido texto, discutimos a possibilidade de o mesmo levar o estudante a um entendimento das noções fundamentais de energia, mediante a contextualização histórica, social, política, econômica e ambiental dessas noções.