Augusto Tavares de Lyra em vários tons

El presente estudio tiene por objetivo, analizar las prácticas políticas-intelectuales de Augusto Tavares de Lyra, perteneciente a una elite que gobernó el estado de Río Grande del Norte de Brasil, durante los dos primeros decenios de la República Vieja , de 1889 a 1918. El recorte temporal considerado tiene inicio al final del siglo XIX, en 1872, a��o de su nacimiento, hasta el a��o 1958, cuando falleció a los casi ochenta y seis a��os de vida. Mientras tanto, analizaremos vivencias y prácticas de Tavares de Lyra como hombre público a partir de los documentos investigados. Utilizamos como soporte principal artículos, reportajes, discursos y libros escritos por sus contemporáneos. Observamos que las fuentes documentales, tales como mensajes, leyes y decretos gubernamentales, bibliografías sobre el período evocado y el archivo del intelectual Tavares de Lyra. Entendemos que, aunque fuera un político de prácticas liberales y empeñado en reformar el sistema educativo brasilero, él fue fruto de un instante de la política nacional, que privilegió pocos núcleos familiares en detrimento de la democracia descrita solamente en la ley, y que por eso, poseía comprometimiento con las prácticas de la Primera República. Su legado reside en una obra literaria ligada directamente al Instituto Histórico y Geográfico Brasileiro y a los estudios realizados, en cuanto jurista y economista, conocedor de los problemas que afligían Brasil en esa época

O marketing e a atua��ão social das empresas: uma rela��ão possível

The present work is about a study of multiple cases with exploratory and descriptiveperspective and qualitative emphasis. Its field of study is constituted by three local companieswith description of social performance, with emphasis in the personal interview with thecontrollers. Its main objective consists of understanding as it has occurred the marketingrelation with the enterprise social performance in the context of these companies located inthe State of the Rio Grande do Norte who carry out social investments. For this, it hassearched to analyze the types and characteristics of the developed social actions, to evaluatethe motivations and objectives of the accomplishment of social actions, to verify theimportance and influence of the social performance in the dynamics of the companies, toverify the level of specific knowledge and information in the areas of marketing and socialperformance in the companies and to evaluate the process of communication (promotion andspreading) of the social performance carried out by the companies. It has been verified thatthe company A directly associates it its social and ambient activities with differentiationbenefits, competitiveness, creation of value, loyalty, relationships, image, prestige,positioning of the company, sale and financial return, beyond benefits in the internal level asbigger motivation of its employees and retention of talents, not existing rejection to theinterlacement of the concepts related to the marketing and the social one. Already in companyB rejection in relating its practical social to the marketing, being observed after posteriorquestionings, that the relation of direct and indirect form exists and those divulgations of theseactions are carried out, contradicting the arguments of the controllers of that the actions wouldnot be carried out to generate media. In company C, it been verified rejection andcontradiction with relation to the concepts related to the marketing, alleging itself that theimage of the harnessed company to its social performance is not used in proper benefit,evidencing itself that this company divulges its action and is marketable benefited, even so isnot this the main objective of its social programs. It has concluded that the association ofthese two concepts is positive and favorable to the development of the businesses and thesocial actions of the companies, legitimizing them and benefiting the involved company,groups in the actions and the society that profits socially from the private social involvement in the social matters

Estudo de revestimentos inorgânicos com inibidor de corrosão aplicado na superfície do concreto

The corrosive phenomenon on reinforced concrete structures is one of the most founded pathologies on the coastal area. With the objective to prevent the process development, or even, retard its beginning, it was studied the application of inorganic covering over concrete surfaces, after its cure, as well as, evaluate the efficiency of the covering applied on the concrete in reducing its porosity of concrete preventing the entrance of aggressive agents to preserve the integrity of the existing armor inside it, comparing the result obtained with the body-of-proof reference, that didn´t receive covering protection. On the concrete production it was used Portland Cement CP II 32, coarse aggregate, fine aggregate and water from the local distributive. Two types of covering were used, one resin based of silicon and solvent and other white cement based, selected sands and acrylic resin. The concrete mixture adopted was 1:1,5:2,5 (cement, fine aggregate, coarse aggregate) and 0.50 water/cement ratio. With the concrete on fresh state was made the experiment test to determinate the workability. On the hardened state was made the concrete resistance experiment, absorption of water and electrochemical experiments, through polarization curves. Also was held optical microscopy and Scanning Electron Microscopy experiments to analyze the layer of the covering applied to the concrete surface and the interface between the concrete and the layer. The obtained results shows that the covering applied to the concrete surface didn´t affect the resistance towards compression. On the absorption of water occurred a diminution of the percentage absorbed, improving the concrete development by making it more impermeable towards the entrance of aggressive agents. The electrochemical experiment results confirmed the water absorption results; the body-of-proof covered presented larger protection towards the development of corrosives process and retarded the evolution of the corrosive phenomenon

Estudo sobre o efeito dos parâmetros de processamento dos pós e sinteriza��ão do a��o inox 316l reforçado com NbC

This masther dissertation presents a contribution to the study of 316L stainless steel sintering aiming to study their behavior in the milling process and the effect of isotherm temperature on the microstructure and mechanical properties. The 316L stainless steel is a widely used alloy for their high corrosion resistance property. However its application is limited by the low wear resistance consequence of its low hardness. In previous work we analyzed the effect of sintering additives as NbC and TaC. This study aims at deepening the understanding of sintering, analyzing the effect of grinding on particle size and microstructure and the effect of heating rate and soaking time on the sintered microstructure and on their microhardness. Were milled 316L powders with NbC at 1, 5 and 24 hours respectively. Particulates were characterized by SEM and . Cylindrical samples height and diameter of 5.0 mm were compacted at 700 MPa. The sintering conditions were: heating rate 5, 10 and 15◦C/min, temperature 1000, 1100, 1200, 1290 and 1300◦C, and soaking times of 30 and 60min. The cooling rate was maintained at 25◦C/min. All samples were sintered in a vacuum furnace. The sintered microstructure were characterized by optical and electron microscopy as well as density and microhardness. It was observed that the milling process has an influence on sintering, as well as temperature. The major effect was caused by firing temperature, followed by the grinding and heating rate. In this case, the highest rates correspond to higher sintering.

Desenvolvimento de bloco de veda��ão com barita na composição de partida para blindagem de radia��ão X

This work main objective is to study the use of bricks in barium X-rays rooms in order to contribute to the optimization of shielding rooms diagnosis. The work was based on experimental measurements of X-ray attenuation (40 to 150 kV), using ceramic seal bearing the incorporation of barium sulfat (BaSO4). Different formulations were studied in three different firing temperatures and evaluated for incorporation in the ceramic body. The composition of 20% of barite processed at a temperature of 950 ° C showed better physical and mechanical properties, is considered the most suitable for the purpose of this work. Were produced bricks sealing composition formulated based on that presented the best technological features. These blocks were tested physically as a building material and wall protective barrier. Properties such as visual, deviation from the square, face flatness, water absorption and compressive strength were evaluated for all the blocks produced. The behavior of this material as attenuator for X-rays was investigated by experimental results which take into account mortar manufacturers barium through the different strains and compared with the reference material (Pb). The simulation results indicated that the ceramic block barium shows excellent properties of attenuation equivalence lead taking into account the energy used in diagnostic X-ray

A escola de ensino médio público noturno: uma conjuntura favorável ao protagonismo estudantil coletivo em contraposição ao protagonismo juvenil via empoderamento

Ce travail etude le protagonisme juvénile en école de enseignement sécondaire publique, avec emphase a l enseignement nocturne. Considere las médiations que determinent le paradigme du protagonisme juvénile defendu pour théoriciens pos modernes et documents de reforme de enseignement sécondaire brésilien. Montre que les explications sur le protagonisme juvénile font part d une conception de pouvoir juvenile, proposé pour organismes multilatérales avec la volonté de mobiliser les jeunes pauvres pour faire actions du combat a pauvreté dans les nations sur le point de développement, conjoncture auquel sont proposées théories et pratiques que viabilizent la subsistance des jeunes pauvres en situation de risque. Discute la question de pouvoir juvenile et indique que la proposition de le protagonisme juvénile via pouvoir ont une espace favorable dans le sphère du enseignement sécondaire, niveau de la plupart de jeunes. Montre que la défense de pouvoir juvenile occulte chances de actions étudiants collectifs que permetent une intervention sociopolitique au élève de enseignement sécondaire, qui ont selement une function de homologation. Propose une recherche de possibilités de incentifs a le protagonisme juvénile collectif ou protagonisme étudiant collectif, auquel le étudiant presente suggestions pour le planification et éxecution de activités didactique pédagogiques dans l`école publique de enseignement sécondaire. Defend que la gestion démocratique, avec emphase en proc��s participatif, c est la principal déterminacion pour le protagonisme étudiant collectif. Méthodiquement , considere las dimensions suivantes pour le protagonisme juvénile: a) configuration de protagonisme juvénile b) protagonisme juvénile dans perspective légal/institutionel ; c) enseignement sécondaire et protagonisme juvénile ; d) possibilité de construction de protagonisme étudiant collectif dans enseignement sécondaire nocturne en Rio Grande do Norte, état choisi pour recherche. Sistematize une technique de revision de litérature sur le thème et informations d une consultation de documents, au-delà de donné constants de Banc de donées de la recherche Le Enseignement Sécondaire Publique Nocturne :registre et analyse de expérience dans l état de Rio Grande do Norte. Conclusion : il faut contribuer pour débats sur la participation politique de les jeunes dans le enseignement sécondaire nocturne, en presentant possibilités reéles de protagonisme étudiant collectif ; opinions presentées pour élèves sont très importantes a une direction d un rôle académique fait pour institutions scolaires dans ce moment , parce que des étudiants sont correspondants a interlocuteurs privilégiés ; le élève peut et deut être consulté depuis le moment de élaboration jusqu a réalisation de activités scolaires ; bien que il y a des entraves et difficultés immanents au enseignement sécondaire publique nocturne, se forment noveaux espaces de démocratisation de idées

Cinema e educação :interfaces, conceitos e práticas docentes

This project goes beyond the interfacial field of cinema, History and education. We take as our object the epistemological potential of the cinema at the educational scenario, specifically the use of films integrated to the practices of History teachers and educative processes in which we have taken part as a builder. Our objective is to map, initially, the knowledge around this use to search a synthesis and its empirical application. From the methodological point of view, we have made use of different perspectives: (a) interviews with the educator subjects; (b) observation of their practices and formative circumstances; (c) filmic analysis and the relation of the cinema s epistemology with the other areas ones (initially History and further Journalism). Our analysis allowed us to portrait the film such as an epistemological-troubling category, what makes the cinema rather a builder technology and not simply a complementary and illustrative technological resource. Therefore, we have realized that the restriction to the cinema s educational function is linked to the restrictions to the theoretical categories to an only interfacial aspect: historical film as a film which portraits the past (at the historical field) and film on journalism as a film which approaches a single object of Journalism (at the journalistic field). These discussions happen, consequently, at the arena of the nature of cinema s genres (fiction and documentary), which are understood in a na��ve way, simpler than its epistemological possibilities, boosted at this research when we analyze the confluence between fiction and reality. The reflections on educative practices and in formation related to the cinema had occurred in three empirical realities: research with professors in performance, practices docent s and accompaniment of students of history. Have to do with our personal career as a teacher and researcher and, when analyzed other practices, have become, unavoidably, the subject and object of this project

O riso irônico na obra poética de Cruz e Sousa

This work brings up a review on the poetic works of Cruz e Sousa, a nineteenth-century Brazilian poet. Laughter has been chosen as an analytical category, because it is a pertinent theme which makes possible a more accurate comprehension of the lyric content of Cruz e Sousa s poetic works. The laughter manifested in his verses is seen as a mechanism which compensates both normativeness and seriousness, as well as turns inside out whatever society establishes as being natural or an absolute truth. Amongst his poems, we will focus on the ones which express their lyric nature both through laughter and irony, since these elements serve as a means to criticize the Brazilian society in the late nineteenth-century and early twentieth-century. This study is guided by theories of laughter proposed by Minois (2003), Bakhtin (1993), Bergson (2007), as well as Adorno s (2003) and Antonio Candido s (2010) theoretical assumptions concerning lyric poetry and society

A implementa��ão do voc�� em cartas pessoais norte-riograndenses do século XX

Considering the theoretical and methodological presuppositions of Variationist Sociolinguistics (cf. WEINREICH; LABOV; HERZOG, 2006; LABOV, [1972] 2008), in this dissertation, we describe and analyze the process of variation/change involving the personal pronouns tu and voc��, and its extension in the pronominal paradigm in Brazilian Portuguese (BP), in three sets of personal letters written by people from Rio Grande do Norte (RN) along the 20th century. The discursive universe of those letters is news from the cities in which the informers lived and the themes from their everyday life (trade, jobs, trips, family and politics). Part of the analyzed letters integrate the written by hand minimum corpus of the Projeto de História do Português Brasileiro no Rio Grande do Norte (PHPB-RN). We are based on previous studies about the pronominal system in BP Menon (1995), Faraco (1996), Lopes e Machado (2005), Rumeu (2008), Lopes (2009), Lopes, Rumeu e Marcotulio (2011), Lopes e Marcotulio (2011) e Martins e Moura (2012) , which register the form voc�� replaces tu from the end of the first half of 20th century and attest the following situation: while (a) the imperative verbal forms, (b) the explicit subjects and (c) prepositional complement pronouns are favorable contexts for voc��, the (d) non imperative verbal forms (with null subject), (e) the non prepositional complement pronoun and (f) the possessive pronoun are contexts of resistance of tu. The results got in this dissertation confirm, partially, the statements defended by the previous studies regarding the favorable contexts for the implementation of voc�� in BP: (i) there are, in the letters from the first two decades of 20th century (1916 to 1925), high frequency of the usage of the form voc�� (98%); (ii) in the personal letters of RN especially in the love letters, in which there are higher recurrence of intimate subjects the discursive universe proved to be itself very relevant in the determination/conditions of the forms of tu; (iii) the unique feminine informer of our sample uses, almost categorically, the forms of tu in letters of the period from 1946 to 1972; (iv) the letters corresponding to the period from 1992 to 1994 present a significant usage of the forms associated to the innovating voc��, letting appear the change is already implemented in the system of BP and there are, in that set of letters, strong evidences that make us state the pronominal forms of non prepositional complement (accusative/ dative) related to tu are also implemented in a system with an almost categorical usage of voc��

Estudo comportamental, hormonal e histopatológico de animais com perda de peso progressina (SEP) e da variável peso associada a uma nova classificação ontogenética em Callithrix jacchus

The use of non-human primates in scientific research has contributed significantly to the biomedical area and, in the case of Callithrix jacchus, has provided important evidence on physiological mechanisms that help explain its biology, making the species a valuable experimental model in different pathologies. However, raising non-human primates in captivity for long periods of time is accompanied by behavioral disorders and chronic diseases, as well as progressive weight loss in most of the animals. The Primatology Center of the Universidade Federal do Rio Grande do Norte (UFRN) has housed a colony of C. jacchus for nearly 30 years and during this period these animals have been weighed systematically to detect possible alterations in their clinical conditions. This procedure has generated a volume of data on the weight of animals at different age ranges. These data are of great importance in the study of this variable from different perspectives. Accordingly, this paper presents three studies using weight data collected over 15 years (1985-2000) as a way of verifying the health status and development of the animals. The first study produced the first article, which describes the histopathological findings of animals with probable diagnosis of permanent wasting marmoset syndrome (WMS). All the animals were carriers of trematode parasites (Platynosomum spp) and had obstruction in the hepatobiliary system; it is suggested that this agent is one of the etiological factors of the syndrome. In the second article, the analysis focused on comparing environmental profile and cortisol levels between the animals with normal weight curve evolution and those with WMS. We observed a marked decrease in locomotion, increased use of lower cage extracts and hypocortisolemia. The latter is likely associated to an adaptation of the mechanisms that make up the hypothalamus-hypophysis-adrenal axis, as observed in other mammals under conditions of chronic malnutrition. Finally, in the third study, the animals with weight alterations were excluded from the sample and, using computational tools (K-means and SOM) in a non-supervised way, we suggest found new ontogenetic development classes for C. jacchus. These were redimensioned from five to eight classes: infant I, infant II, infant III, juvenile I, juvenile II, sub-adult, young adult and elderly adult, in order to provide a more suitable classification for more detailed studies that require better control over the animal development

Influência de fatores individuais e sociais sobre as respostas endócrina e comportamental de callithrix jacchus a desafios ambientais físicos e sociais

Regarding the growing number of human beings with physical and mental pathologies associated to different stressor agents, attempts are being made to validate animal models with a close phylogenetic resemblance to man, to study stress response. Callithrix jacchus has been widely used in biomedical research, including on stress, but there is scarce information in the literature about how individual and social factors modulate stressor response in this species. This study uses 4 approaches to investigate the response of male and female adult C. jacchus, under situations of stress, and in the first we show evidence of the importance of this animal as an experimental model in research involving the hypothalamus-pituitary-adrenal axis. And we investigate if sex and baseline cortisol levels modulate the behavioral and hormonal response to separation. In two additional approaches investigate if type of social support (co-specific parent or non-parent) and social rank interfere in behavioral and hormonal when the animal are exposure to a new environment, paired with a co-specific (F2), exposure of the animal to a new environment, isolated (F3) or during reunion (F4). Finally, we also investigated the androgen levels in the males, with a focus on the challenge hypothesis, referring to environmental responsiveness and male-male exposure to relatives and non-relatives of C. jacchus. It was observed that: (1) the baseline cortisol of the animal is predictive of cortisol reactivity at separation; (2) males and females do not show dimorphism in the response of cortisol to stressors, although the females have higher baseline levels of this hormone and exhibit higher frequencies of anxiety-related behaviors; (3) only social support provided by relatives proved to be effective in buffering the cortisol response. In behavioral terms this response was dimorphic, showing that only the male dyads displayed an attenuated response to stress; (4) the males showed differences in cortisol levels as a function of social rank and study phases, whereas in the females no such alterations were observed. The males with indefinite dominance hierarchy (IDH) had reduced cortisol in F2 and F4, while the IDH females showed an increase in F3 and F4; (5) the males of relative and non-relative dyads did not exhibit variations in androgen levels as a function of a new environment. These results, taken together, (a) corroborate the use of C. jacchus as a good animal model for stress-related studies, given that they exhibit similar behavioral and physiological alterations to those of human beings in response to stressor agents; (b) point to the importance of considering individual and social modulating factors during experiments with stressors; (c) provide more reliable comparison parameters in studies where these primates are used as animal models, and (d) show that androgens vary as a function of genetic proximity (relative or non-relative) when the animals are faced with physical and social environmental challenges, thus providing important information for studying the challenge hypothesis in this species

Caracteriza��ão comportamental endócrina das fases ontogenéticas de sagüi comum (Callithrix jacchus)

The use of animal models in biomedical research is ever increasing. Models that use primates might also have advantages in terms of low maintenance costs and availability of biological knowledge, thereby favoring their use in different experimental protocols. Many current stress studies use animal models at different developmental stages since biological response differs during ontogeny. The aims of this study were to perform a detailed characterization of the developmental stages of common marmosets (Callithrix jacchus), a very important animal model used in biomedical research. Ten subjects, 6 females and 4 males, were followed from birth to initial adult age (16 months). Behavioral and fecal collection for measurement of adrenal (cortisol) and sex (progesterone, estradiol and androgens) hormones took place twice a week during the first month of life and once a week for the remainder of the study. Behavior was observed for 30 minutes in the morning (0700-09:00h) and afternoon (12:00-14:00h). Behavioral profile showed changes during ontogeny, characterizing the 4 developmental stages and the respective phases proposed by Leão et al (2009).. Differentiation of developmental stages was considered using the onset, end, change and stabilization of the behavioral profile parental care (weaning and carrying), ingestion (solid food), affiliation (social grooming) and autogrooming, agonism (scent marking and piloerection) and play behavior and endocrine profile. Infant weaning and carrying terminated within the infantile stage and the peak of solid food ingestion was recorded in the infantile III phase. Receiving grooming was recorded earlier than grooming performed by the infant and autogrooming. The first episode of scent marking was recorded in the 4th week and it was the least variable behavior, in terms of its onset, which, in almost all animals, was between the 5th and 7th week of life. Solitary play and play with the twin started around the 7th week and play with other members of the group started 8 weeks later. Sex hormone secretion started to differ from basal levels between the 21st and 23rd week of life, in males and females, suggesting that puberty occurs simultaneously in both sexes. Basal cortisol, even at an early age, was higher in females than in males. However, cortisol was not correlated with the juvenile stage, as expected, since this stage corresponds to the transition between infancy and adult age and most behaviors are intensified by this time. The behavioral and endocrine profile of subadult animals did not differ from that of the adults. These results provide more detailed parameters for the developmental process of C. jacchus and open new perspectives for the use of experimental approaches focused on the intermediate ontogenetic phases of this species

Comportamento de parâmetros fisiológicos de homens e mulheres em condições de estresse laboral submetidos à técnica Watsu

The physiological variations of parameters in situations of laboral stress can function like indicator in the sprouting of disorder. Those conditions have led researchers to investigate alternatives that can favor the quality of life in persons under stress laboral. The present research had as objectives investigate the physiological behavior of parameters (blood pressure, heart hat and respiratory hat) of men and women in condition of stress laboral submitted to the technique Watsu. It was used a experimental methodology with a group formed by men and women in reproductive age, that work as salesclerk in a supermarket net in Natal/RN. The seven individuals selected were submitted to the three phases of the study (dependent groups), that consisted of the phase 1 of obtaining from the measure basal (control 1), in the phase 2 of immersion in the water (control 2), and phase 3 from the application the technique Watsu (experimental phase). It was verified that during the phase basal (condition 1) the physiological parameters (BPS, BPD, HH and RH) of both sexes evaluated showed the medium values of the women (average±detour-standard: BSP = 104.1±7.92; BPD = 70.83 ±7.92; HH = 77.58 ±3.87; RH = 19.83 ±2.58) similar those presented by the men (BPS = 118.75 ±7.55; BPD = 75.00 ±9.91; HH = 71.75 ±14.95; RH = 16.62 ±3.99). The evaluation of those parameters before and after immersion of the volunteers in the water (condition 2) showed a significant reduction (W = 3.0: p≤0.05) barely for the values of BPS presented by the sex females after immersion. In the men group, all of the physiological parameters analyzed did not vary significantly. Regarding the profile of those variables before and after application of the watsu (condition 3), was verified a significant increase (W= 0,0: p≤0.05) for the BPS one and SABP in the women. The Men did not show significant variation for all of the physiological parameters. Faced with the results presented, we are able to conclude that the systolic and diastolic blood pressures were the physiological parameters that are on influence from the Technique Watsu, only for the kind females

Modelos de condutividade térmica em rochas silic��ticas, com ênfase em rochas da província Borborema, NE do Brasil

A practical approach to estimate rock thermal conductivities is to use rock models based just on the observed or expected rock mineral content. In this study, we evaluate the performances of the Krischer and Esdorn (KE), Hashin and Shtrikman (HS), classic Maxwell (CM), Maxwell-Wiener (MW), and geometric mean (GM) models in reproducing the measures of thermal conductivity of crystalline rocks.We used 1,105 samples of igneous and metamorphic rocks collected in outcroppings of the Borborema Province, Northeastern Brazil. Both thermal conductivity and petrographic modal analysis (percent volumes of quartz, K-feldspar, plagioclase, and sum of mafic minerals) were done. We divided the rocks into two groups: (a) igneous and ortho-derived (or meta-igneous) rocks and (b) metasedimentary rocks. The group of igneous and ortho-derived rocks (939 samples) covers most the lithologies de_ned in the Streckeisen diagram, with higher concentrations in the fields of granite, granodiorite, and tonalite. In the group of metasedimentary rocks (166 samples), it were sampled representative lithologies, usually of low to medium metamorphic grade. We treat the problem of reproducing the measured values of rock conductivity as an inverse problem where, besides the conductivity measurements, the volume fractions of the constituent minerals are known and the effective conductivities of the constituent minerals and model parameters are unknown. The key idea was to identify the model (and its associated estimates of effective mineral conductivities and parameters) that better reproduces the measures of rock conductivity. We evaluate the model performances by the quantity  that is equal to the percentage of number of rock samples which estimated conductivities honor the measured conductivities within the tolerance of 15%. In general, for all models, the performances were quite inferior for the metasedimentary rocks (34% <  < 65%) as compared with the igneous and ortho-derived rocks (51% <  < 70%). For igneous and ortho-derived rocks, all model performances were very similar ( = 70%), except the GM-model that presented a poor performance (51% <  < 65%); the KE and HS-models ( = 70%) were slightly superior than the CM and MW-models ( = 67%). The quartz content is the dominant factor in explaining the rock conductivity for igneous and ortho-derived rocks; in particular, using the MW-model the solution is in practice vi UFRN/CCET– Disserta��ão de mestrado the series association of the quartz content. On the other hand, for metasedimentary rocks, model performances were different and the performance of the KEmodel ( = 65%) was quite superior than the HS ( = 53%), CM (34% <  < 42%), MW ( = 40%), and GM (35% <  < 42%). The estimated effective mineral conductivities are stable for perturbations both in the rock conductivity measures and in the quartz volume fraction. The fact that the metasedimentary rocks are richer in platy-minerals explains partially the poor model performances, because both the high thermal anisotropy of biotite (one of the most common platy-mineral) and the difficulty in obtaining polished surfaces for measurement coupling when platyminerals are present. Independently of the rock type, both very low and very high values of rock conductivities are hardly explained by rock models based just on rock mineral content.

Estudo da adição de resíduos de quartzitos para obtenção de grés porcelanato

In States of Para��ba (PB) and Rio Grande do Norte (RN), northeast of Brazil, the most significant deposits of non-metallic industrial minerals are pegmatites, quartzites and granites, which are located in Seridó region. Extraction of clay, quartz, micas and feldspars occurs mainly in the cities of Várzea (PB), OuroBranco (RN) and Parelhas (RN). Mining companies working in the extraction and processing of quartzite generate large volumes of waste containing about 90% SiO2 in their chemical composition coming from quartz that is one of the basic constituents of ceramic mass for the production of ceramic coating. Therefore, this work evaluates the utilization of these wastes on fabrication of high-quality ceramic products, such as porcelain stoneware, in industrial scale. Characterization of raw materials was based on XRF, XRD, GA, TGA and DSC analysis, on samples composed by 57% of feldspar, 37% of argil and 6% of quartzite residues, with 5 different colors (white, gold, pink, green and black). Samples were synthesized in three temperatures, 1150°C, 1200°C and 1250°C, with one hour isotherm and warming-up tax of 10°C/min. After synthesizing, the specimens were submit to physical characterization tests of water absorption, linear shrinkage, apparently porosity, density, flexural strain at three points. The addition of 6% of quartzite residue to ceramic mass provided a final product with technological properties attending technical norms for the production of porcelain stoneware; best results were observed at a temperature of 1200°C. According to the results there was a high iron oxide on black quartzite, being their use in porcelain stoneware discarded by ethic and structural question, because the material fused at 1250°C. All quartzite formulations had low water absorption when synthesized at 1200°C, getting 0.1% to 0.36% without having gone through the atomization process. Besides, flexural strain tests overcame 27 MPa reaching the acceptance limits of the European Directive EN 100, at 1200°C synthesizing. Thus, the use of quartzite residues in ceramic masses poses as great potential for the production of porcelain stoneware.