Obtenção de compósitos cerâmicos baseados em Al2O3/TiC através dos precursores poliméricos

The obtaining of ceramic materials from polymeric precursors is subject of numerous studies due to lower energy costs compared to conventional processing. The aim of this study is to investigate and improve the mechanism for obtaining ceramic matrix composite (CMC) based on SiOC/Al2O3/TiC by pyrolysis of polysiloxane in the presence of an active filler and inert filler in the pyrolysis temperature lower than the usually adopted for this technique, with greater strength. It also investigates the influence of pyrolysis temperature, the content of Alas active filler, the presence of infiltrating agents (Al, glass and polymer) after pyrolysis, temperature and infiltration time on some physical and mechanical properties. Alumina is used as inert filler and Al and Ti as active filler in the pyrolysis. Aluminum, glass and polysiloxane are used as agents infiltrating the post-pyrolysis. The results are analyzed with respect to porosity and bulk density by the Archimedes method, the presence of crystalline phases by X-ray diffraction (XRD) and microstructure by scanning electron microscopy (SEM). The ceramic pyrolyzed between 850 °C 1400 °C contain porosity 15% to 33%, density 2.34 g/cm3 and flexural strength at 4 points from 30 to 42 MPa. The microstructure features are porous, with an array of Al2O3 reinforced by TiC particles and AlTi3. The infiltration post-pyrolysis reveals decrease in porosity and increase density and strength. The composites have potential applications where thermal stability is the main requirement

A Metafísica da luz em Marcílio Ficino.

The aim of the present dissertation constitutes to analyse the way in how light assumes the meaning of universal bond in the cosmovision of Marsilio Ficino, especially from his works Quid sit lumen, De Sole, De Amore and De Vita. The influence of Marsilio Ficino (1433-1499) in the history of occidental thought is impressive. Besides having translated to Latin the important texts of the neoplatonic tradition, Ficino presided over the Academy of Careggi, congregating important humanists in the top of the Renaissance. His treatises on love, beauty, light, magic and immortality of the soul have influenced strongly the production of other thinkers. The subject of light is of fundamental importance among his works since it is deeply related with all the other aspects of his philosophy. For him, light is spiritual emanation that perpasses everything without staining itself. Originated how the divine goodness, the light blows up in beauty in multiplicity, setting fire on the soul that truily contemplates it and that identifies whith it. The starting point of this loving relation between man and deity is, therefore, the physical world, that occults in itself the metaphysical light.

Liberdade e negação da vontade: análise do ser-livre como representação e na angústia

Common understanding about what freedom means has always been more or less related to the power to realize something intended, desired, a capability. Therefore, being free is commonly interpreted under the concept of free-will and the category of possibility to act. Although there are predecessors in History of Philosophy, Schopenhauer refuses the thesis of free will proposing otherwise the denial of willing (to live) as the ultimate possibility for human freedom, if not the only one left. The thesis that would make him famous was deeply misunderstood and so miscarried somewhat due to the way it was many times presented by the means of exotic examples wrapped in a mystical mood besides exaltations to Eastern traditions, which may satisfy anthropological curiosity instead of being capable to satisfy the reader in a philosophical way. It seems to result from Schopenhauer s thought a kind of pessimism against life. Otherwise, typical readings on the Schopenhauerian thesis are found full of inconsistencies once closely regarded, which blame does not belong to the author but to his interpreters. A new reading about the denial of willing as the ultimate possibility for human freedom demands a criticism on the inconsistencies and prejudgments deep grounded. For this, we firstly clarify the ways of understanding the willing nothing , which cannot be reduced to the mere refusal or conformism, being instead positively understood as a special manner of willing: the admission of oneself for the sake of one is. A few more than a century later The world as will and representation came to light, Heidegger proposes in his fundamental ontology that the proper being-free concerns to originary decision by which, in anguish of being suspended in nothingness, Dasein renders itself singular as the being who is in-a-world and to-death, concluding that the ultimate possibility of freedom is being-free-to-death. Developing the hypothesis that freedom, properly understood, concerns to nothingness as to indeterminate possibilities, we seek for a dialogue between Schopenhauer s thought and existential philosophy aiming to reconstitute and overcome Metaphysics tradition turning the question about freedom into a matter of Ontology. From the factual existence perspective, as we must show, every human activity (or inactivity) is ordinarily mediated by representations, in which me and world appear as distinct entities. So, each one among determininate individuals finds itself connected to the things in the world by interest, which proper concept must be sufficiently explored. Starting from this point, we may proceed to detailed analysis of usual representations of freedom aiming their destruction by Ontology and then reaching existential thesis according to Kierkegaard and Heidegger. Turning back to the analysis of Schopenhauer s work, we conclude existential understanding of freedom as will-to-be can also be found in Schopenhauer. In this way, denial of willing means ultimate freedom once the Will turns back to its own essence by suppressing the world as representation, which means the originary absolute indetermination of the extreme possibility to-be

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

A Relação formação profissional / Mercado de Trabalho: percepção dos assistentes sociais não-inseridos no mercado de trabalho do Serviço Social em Natal/RN

The study is about the non-insertion of the Social Assistant in the work market of Natal/RN, emphasizing the perception those Social Assistants have about this problem. We try to analyze the relation that those workers figure out about their non-insertion in the work market and their professional formation. The problem is related to the present unemployment rates in our society, which results of the changes that have affected the world of work as a whole in the wake of the Productive Restructuring and State Reformation supported by the neo-liberalism ideological system. We realize that these factors have deeply affected the configurations of the work market in general; especially those related to professions whose challenges multiply obstacles not only to the insertion of new workers, but to their staying in their job. We note that the reality of the work market has been built up on the decrease of the work force opportunities and the increase of the selectivity criteria to insertion of new workers. In consequence, unemployment rates increase everywhere, regardless of place, profession or education level of the workers. Work and management changes have brought about new challenges to professional formation. The presence of neo-liberalism productive and market logic demands a more adequate professional formation to work market from their candidates to a job. Due to the numberless difficulties workers face nowadays to enter the world of work, society itself and workers in general begin to question the profession of their choice, the kind of formation they have got, and frequently they lay the blame of their professional difficulties on it. This result has come out from the research we did with some social assistants not inserted in the professional work market in Natal/RN. The research reveals too that those unemployed professionals see their difficulties connected to their professional formation and they happen to say that the main challenge they face today is to get acknowledgment to the significance and importance of their profession

Poluição sonora: um grave problema na cidade de Mossoró-RN

In the latest decades, we have observed some environment alterations of big proportions in our planet. Sound pollution, visual pollution, water pollution, air pollution, soil pollution, all the principal kinds of environment pollution have raised in the path of economy development. In Mossoró it is not different; the environment has suffered a long and continuous damage caused by predatory abuse. The river is polluted, the ciliar vegetation of Carnauba was totally altered and with it a part of the local fauna disappeared. In fact, the city urban environment has, and continues to be, deeply altered and the sound pollution is a reflex of the urban modifications undergone in the city as time goes by. Through bibliographic review, the gauging of noise and fieldwork, this research project had the objective of analyzing the principal activities that cause sound pollution in the urban perimeter of the city of Mossoró, RN, emphasizing the causes, effects and spacial distribution of the polluter agents, as well as understanding how the environmental laws treat the sound issue in the urban environment of the city. The President Dutra avenue, where popular events of Mossoró take place and an important access for the city, was the chosen place to study this pollution that became, recently, another hindrance that interferes on the life quality of the local population. The results of this brief research emphasizes the urgency to alert society, specially about the importance of law and public organs that are located in our city, therefore solving problems such as the aforementioned above

Análise da estrutura genética populacional da piraúna (cephalopholis fulva: serranidae) ao longo da costa e ilhas oceânicas brasileiras

Brazil has about 8,500 km of coastline and on this scale, fishing is a historically important source of animal protein for human consumption. The national fishing background shows a growth of marine fishery production until 1985 and within this period it was recorded a steady decline. From the year 2003 fishing statistics aim to some "recovery" of the total fisheries production, which probably is related to a change in industry practice. The target of commercial fishing became smaller species with low commercial value, but very abundants. The coney, Cephalopholis fulva (Serranidae), is one of these species that have been suffering a greater fishing pressure in recent years. In order to provide data about the current situation of the genetic diversity of these populations, several molecular markers have been being used for this purpose. The prior knowledge of genetic variability is crucial for management and biodiversity conservation. To this end, the control region sequences (dloop) of mtDNA from Cephalopholis fulva (Serranidae) from five geographical points of the coast of Brazil (Ceará, Rio Grande do Norte, Bahia and Espírito Santo) and the Archipelago of Fernando de Noronha (FN) were sequenced and their genetic diversity analyzed. The FST values were very low (0.0246 to 0.000), indicating high gene flow between the sampled spots. The indices h and indicate a secondary contact between previously allopatric lineages differentiated or large and stable populations with long evolutionary history. Tests of Tajima and Fu showed expansion for all populations. In contrast, the mismatch distribution and SSD indicated expansion just for coastal populations. Unlike other species of the Atlantic which have been deeply affected by events on later Pleistocene, the population-genetic patterns of C. fulva may be related to recent events occurred approximately 130,000 years ago. Moreover, the data presented by geographical samples of the specie C. fulva showed high genetic diversity, also indicating the absence of deleterious effects of over-exploitation on this specie, as well as evidence of complete panmixia between all sampled populations

Estudos sedimentológicos e o contexto estrutural da formação Serra do Martins, nos platôs de Portalegre, Martins e Santana/RN

This dissertation deals with sedimentological and structural framework of the siliciclastic rock of the Serra do Martins Formation (FSM) in the Portalegre, Martins and Santana plateau, located to the south of Potiguar Basin, in the southwest and central Rio Grande do Norte state. This formation, regarded as of Oligo-Miocene age based on intrusive relations of the Miocene Macau volcanics, has a still disputable age due to the lack of appropriate bio and/or chronostratigraphic markers. The FSSM deposits crop out along 650 to 750 m high plateau, as a remanescent sedimentary cover directly overlying topographically uplifted pre-cambrian crystalline rocks. During the last decades, these deposits were interpreted according to a Tertiary paleoclimatic evolutionary model, associated to pedogenetic processes. The sedimentological characterization of the FSM was done through a detailed study of its facies, petrography and diagenetic features. The facies study was based on description of field relations, textures and structures, the piling up of the strata and their lateral variations. The FSM was deposited by an anastomosing to coarse-meandering fluvial system, including deposits of lag, cannel-fill, ouver-bank and flood plain. The petrographic composition of the sediments, coupled to their facies and paleocurrent directions, suggest a rather distal sourcearea, to the south of the present plateau. The diagenetic study identified an incipient grain mechanical compaction, pronounced dissolution of the framework, matrix and/or cement components, intense precipitation of kaolinite, silic and, eventually, iron oxides, besides mechanical infiltration of the clays. Most of these events, regarded in the literature as associated to near-surface conditions (eo or telodiagenesis), indicate the FSM sediments were never deeply buried. Topographic relations along longitudinal and transversal sections reaching the Potiguar Basin to the north identified regional dips that allow to discuss stratigraphic correlations between the FSM and the basin formations. The sedimentological features of the different units and the intrusive relations of the Macau volcanics were also considered in these correlations,which support the Oligo-Miocene age previously accepted for the FSM. Concerning the tectonic framework of the FSM, this work investigated the pre-cambrian to cretaceous heritage and the cenozoic deformation, allowing the recognition of pre-, sin and post-FSM structures. The crystalline basement, belonging to the Seridó Belt, displays NE and WNW foliation trends related to the Brasiliano-age ductile shear zones. In this terrain, brittle-ductile and brittle NE- and NW-trending structures, associated with extensional joints filled with pegmatites and quartz veins, are related to an E-W compression by the end of Brasiliano Cycle. The E-W joints and NE-trending fractures were reactivated by N-S to N-S to NW extension during late Jurassic to Cretaceous times, controlling the emplacement of the Rio Ceará-Mirim basic dyke swarm and the opening of the Potiguar rift basin

Setor terciário e informalidade: algumas especificidades da (re)produção do espaço urbano de Bayeux-PB

This work has as study object the tertiary sector and (the re)production of the urban space of Bayeux-PB. For in such a way, one became necessary to the construction of a theoretical boarding that context the national reality, to be able itself to understand the reality local. This way to construct allowed an opening of the field of vision how much to the relevance of if ahead studying the tertiary sector and its weight of the current configuration of the society in a country as Brazil, e especially in a city of a State northeastern, as it is the case of Bayeux. The theoretical boarding had as base the two circuits of the urban economy, the productive reorganization and the transformations in the world of the work, as well as, the space organization and the distinction between the economic and social space of the tertiary activities, from the logic of functioning of the establishments: the regulation. Besides working with referring official data to the tertiary sector, the empirical study it had as reference one hundred and sixty and establishments tertiary, located in four axles of circulation of the city of Bayeux - PB, which are: Av. Liberdade, Av. Engenheiro de Carvalho, Av. Francisco Marques da Fonseca and Av. Marechal Rondon, that they had appeared in such a way stimulated for the processes of urbanization and industrialization lived deeply from years 70 in the "Great João Pessoa" how much, in the countries of the underdeveloped capitalist world, as Brazil. Being thus, the objective of the work was to study the tertiary sector and its relation with (the re)production of the urban space, standing out the functioning logic