Estudo térmico e de materiais na construção de casas populares com blocos confeccionados a partir de um composto a base de cimento, gesso, eps e raspa de pneu

We built an experimental house on an UFRN´s land using blocks made by a composite consisting of cement, plaster, EPS, crushed rubber and sand. Several blocks were made from various compositions and we made preliminary tests of mechanical and thermal resistance, choosing the most appropriate proportion. PET bottles were used inside the block to provide thermal resistance. In this work, a second function was given to the bottles: to serve as a docking between the blocks, because the ends of the cylinders came out of each block on top as well as at the bottom, with the bottom cut, allowing to fit of the extremities of the upper cylinder of a block in the lower holes of the other one, which were formed by the cutting already mentioned. Minimum compression tests were performed according to ABNT standards for walls closing blocks (fence). With that house built, we did studies of thermal performance in order to ascertain conditions of comfort, checking external and internal temperatures in the walls and in the ambient, among other variables, such as wind speed and relative humidity. The resulting blocks provided adequate thermal insulation to the environment, where the walls presented differences up to 11.7 ºC between the outer and inner faces, getting the maximum temperature inside the house around 31 °C, within the so-called thermal comfort zone for warm climates. At the end of the experiments it was evident the effectiveness of that construction in order to provide thermal comfort in the internal environment of the house, as well as we could confirm the viability of building houses from recyclable materials, reducing the constructive costs, becoming a suitable alternative for low- incoming families. Moreover, besides the low cost, the proposal represents an alternative use of various recyclable materials, therefore considered an ecological solution

Mecanismos de desgaste, história térmica e ciclo de vida de componentes de um motor de combustão interna de aeromodelo

We developed an assay methodology that considered the temperature variation and the scanning electron microscopy as a method to quantify and characterize respectively the consumption evolution in three 46 LA machines, with internal combustion and two-stroke engines, 7.64 cm3 cylinder capacity, 23.0 millimeters diameter and 18.4 millimeters course, RPM service from 2.000 to 16.000 rpm, 1.2 HP power, and 272 grams weight. The investigated engines components were: (1) head of the engine (Al-Si alloy), (2) piston (Al-Si alloy) and (3) piston pin (AISI 52100 steel). The assays were carried out on a desktop; engines 1 and 2 were assayed with no load, whereas in two assays of engine 3 we added a fan with wind speed that varied from 8.10 m/s to 11.92 m/s, in order to identify and compare the engine dynamic behavior as related to the engines assayed with no load. The temperatures of the engine s surface and surroundings were measured by two type K thermopairs connected to the assay device and registered in a microcomputer with data recording and parameters control and monitoring software, throughout the assays. The consumed surface of the components was analyzed by scanning electron microscopy (SEM) and microanalysis-EDS. The study was complemented with shape deformation and mass measurement assays. The temperature variation was associated with the oxides morphology and the consumption mechanisms were discussed based on the relation between the thermal mechanical effects and the responses of the materials characterization

Desenvolvimento de uma desfribadeira para obtenção da fibra da folha do abacaxi

In 1998 the first decorticator was developed in the Textile Engineering Laboratory and patented for the purpose of extracting fibres from pineapple leaves, with the financial help from CNPq and BNB. The objective of the present work was to develop an automatic decorticator different from the first one with a semiautomatic system of decortication with automatic feeding of the leaves and collection of the extracted fibres. The system is started through a command system that passes information to two engines, one for starting the beater cylinder and the other for the feeding of the leaves as well as the extraction of the decorticated fibres automatically. This in turn introduces the leaves between a knife and a beater cylinder with twenty blades (the previous one had only 8 blades). These blades are supported by equidistant flanges with a central transmission axis that would help in increasing the number of beatings of the leaves. In the present system the operator has to place the leaves on the rotating endless feeding belt and collect the extracted leaves that are being carried out through another endless belt. The pulp resulted form the extraction is collected in a tray through a collector. The feeding of the leaves as well as the extraction of the fibres is controlled automatically by varying the velocity of the cylinders. The semi-automatic decorticator basically composed of a chassis made out of iron bars (profile L) with 200cm length, 91 cm of height 68 cm of width. The decorticator weighs around 300Kg. It was observed that the increase in the number of blades from 8 to twenty in the beater cylinder reduced the turbulence inside the decorticator, which helped to improve the removal of the fibres without any problems as well as the quality of the fibres. From the studies carried out, from each leaf 2,8 to 4,5% of fibres can be extracted. This gives around 4 to 5 tons of fibres per hectare, which is more than that of cotton production per hectare. This quantity with no doubt could generate jobs to the people not only on the production of the fibres but also on their application in different areas

Avaliação e modelagem reológica de fluido de perfuração base água

The determination of the rheology of drilling fluids is of fundamental importance to select the best composition and the best treatment to be applied in these fluids. This work presents a study of the rheological behavior of some addictives used as viscosifiers in water-based drilling fluids. The evaluated addictives were: Carboxymethylcellulose (CMC), Xanthan gum (GX), and Bentonite. The main objective was to rheologically characterize suspensions composed by these addictives, by applying mathematical models for fluid flow behavior, in order to determine the best flow equation to represent the system, as well as the model parameters. The mathematical models applied in this research were: the Bingham Model, the Ostwald de Wale Model, and the Herschel-Bulkley Model. A previous study of hydration time for each used addictive was accomplished seeking to evaluate the effect of polymer and clay hydration on rheological behavior of the fluid. The rheological characterization was made through typical rheology experiments, using a coaxial cylinder viscosimeter, where the flow curves and the thixotropic magnitude of each fluid was obtained. For each used addictive the rheological behavior as a function of temperature was also evaluated as well as fluid stability as a function of the concentration and kind of addictive used. After analyses of results, mixtures of polymer and clay were made seeking to evaluate the rheological modifications provided by the polymer incorporation in the water + bentonite system. The obtained results showed that the Ostwald de Waale model provided the best fit for fluids prepared using CMC and for fluids with Xanthan gum and Bentonite the best fit was given by the Herschel-Bulkley one

Estudo da influência da temperatura na degradação termoquímica da biomassa de avelós

The bio-oil obtained from the pyrolysis of biomass has appeared as inter-esting alternative to replace fossil fuels. The aim of this work is to evaluate the influence of temperature on the yield of products originating from the pyrolysis process of the powder obtained from the dried twigs of avelós (Euphorbia tirucalli), using a rotating cylinder reactor in laboratory scale. The biomass was treated and characterized by: CHNS, moisture, volatiles, fixed carbon and ashes, as well as evaluation of lignin, cellulose and hemicellulose, besides other instrumental techniques such as: FTIR, TG/DTG, DRX, FRX and MEV. The activation energy was evaluated in non-isothemichal mode with heating rates of 5 and 10 oC/min. The obtained results showed biomass as feedstock with potential for biofuel production, because presents a high organic matter content (78,3%) and fixed-carbon (7,11%). The activation energy required for the degradation of biomass ranged between 232,92 392,84 kJ/mol, in the temperature range studied and heating rate of 5 and 10°C/min. In the pyrolysis process, the influence of the reaction temperature was studied (350-520 ° C), keeping constant the other variables, such as, the flow rate of carrier gas, the centrifugal speed for the bio-oil condensationa, the biomass flow and the rotation of the reactor. The maximum yield of bio-oil was obtained in the temperature of 450°C. In this temperature, the results achieved where: content of bio-oil 8,12%; char 32,7%; non-condensed gas 35,4%; losts 23,8%; gross calorific value 3,43MJ/kg; pH 4,93 and viscosity 1,5cP. The chromatographic analysis of the bio-oil produced under these conditions shows mainly the presence of phenol (17,71%), methylciclopentenone (10,56%) and dimethylciclopentenone (7,76%)

Estudo da influência da temperatura na degradação termoquímica da biomassa de avelós (euphorbia tirucalli Linn)

The bio-oil obtained from the pyrolysis of biomass has appeared as inter-esting alternative to replace fossil fuels. The aim of this work is to evaluate the influence of temperature on the yield of products originating from the pyrolysis process of the powder obtained from the dried twigs of avelós (Euphorbia tirucalli), using a rotating cylinder reactor in laboratory scale. The biomass was treated and characterized by: CHNS, moisture, volatiles, fixed carbon and ashes, as well as evaluation of lignin, cellulose and hemicellulose, besides other instrumental techniques such as: FTIR, TG/DTG, DRX, FRX and MEV. The activation energy was evaluated in non-isothemichal mode with heating rates of 5 and 10 oC/min. The obtained results showed biomass as feedstock with potential for biofuel production, because presents a high organic matter content (78,3%) and fixed-carbon (7,11%). The activation energy required for the degradation of biomass ranged between 232,92 392,84 kJ/mol, in the temperature range studied and heating rate of 5 and 10°C/min. In the pyrolysis process, the influence of the reaction temperature was studied (350-520 ° C), keeping constant the other variables, such as, the flow rate of carrier gas, the centrifugal speed for the bio-oil condensationa, the biomass flow and the rotation of the reactor. The maximum yield of bio-oil was obtained in the temperature of 450°C. In this temperature, the results achieved where: content of bio-oil 8,12%; char 32,7%; non-condensed gas 35,4%; losts 23,8%; gross calorific value 3,43MJ/kg; pH 4,93 and viscosity 1,5cP. The chromatographic analysis of the bio-oil produced under these conditions shows mainly the presence of phenol (17,71%), methylciclopentenone (10,56%) and dimethylciclopentenone (7,76%)

Bio-óleo e biogás da degradação termoquímica de lodo de esgoto doméstico em cilindro rotativo

The objective of this study was to produce biofuels (bio-oil and gas) from the thermal treatment of sewage sludge in rotating cylinder, aiming industrial applications. The biomass was characterized by immediate and instrumental analysis (elemental analysis, scanning electron microscopy - SEM, X-ray diffraction, infrared spectroscopy and ICP-OES). A kinetic study on non-stationary regime was done to calculate the activation energy by Thermal Gravimetric Analysis evaluating thermochemical and thermocatalytic process of sludge, the latter being in the presence of USY zeolite. As expected, the activation energy evaluated by the mathematical model "Model-free kinetics" applying techniques isoconversionais was lowest for the catalytic tests (57.9 to 108.9 kJ/mol in the range of biomass conversion of 40 to 80%). The pyrolytic plant at a laboratory scale reactor consists of a rotating cylinder whose length is 100 cm with capable of processing up to 1 kg biomass/h. In the process of pyrolysis thermochemical were studied following parameters: temperature of reaction (500 to 600 ° C), flow rate of carrier gas (50 to 200 mL/min), frequency of rotation of centrifugation for condensation of bio-oil (20 to 30 Hz) and flow of biomass (4 and 22 g/min). Products obtained during the process (pyrolytic liquid, coal and gas) were characterized by classical and instrumental analytical techniques. The maximum yield of liquid pyrolytic was approximately 10.5% obtained in the conditions of temperature of 500 °C, centrifugation speed of 20 Hz, an inert gas flow of 200 mL/min and feeding of biomass 22 g/min. The highest yield obtained for the gas phase was 23.3% for the temperature of 600 °C, flow rate of 200 mL/min inert, frequency of rotation of the column of vapor condensation 30 Hz and flow of biomass of 22 g/min. The non-oxygenated aliphatic hydrocarbons were found in greater proportion in the bio-oil (55%) followed by aliphatic oxygenated (27%). The bio-oil had the following characteristics: pH 6.81, density between 1.05 and 1.09 g/mL, viscosity between 2.5 and 3.1 cSt and highest heating value between 16.91 and 17.85 MJ/ kg. The main components in the gas phase were: H2, CO, CO2 and CH4. Hydrogen was the main constituent of the gas mixture, with a yield of about 46.2% for a temperature of 600 ° C. Among the hydrocarbons formed, methane was found in higher yield (16.6%) for the temperature 520 oC. The solid phase obtained showed a high ash content (70%) due to the abundant presence of metals in coal, in particular iron, which was also present in bio-oil with a rate of 0.068% in the test performed at a temperature of 500 oC.

Diagnóstco geoambiental e avaliação de uso e ocupação do campo de dunas da zona especial de interesse turístco II (ZET-II) Natal/RN

The accelerated pressure of use and occupation of Rio Grande do Norte coastline in the last two decades presented the tourism as its main vector, having as a consequence a strong, articulated and growing real estate speculation of this area. In the Natal County there is a Zona Especial de Interesse Turistico II (Special Zone of Tourism Interest II) (ZET-II), consisted of urban beaches with approximately 8.5 km that is an important seashore of the city. The purpose of this research was identification, characterization and assessment of the process of use and occupation of dunes fields emphasizing the role of ZET-II, whereas the specific goals was the analysis of weather, geology and geomorphology, characterization of use and occupation of soil, and elaboration of an environmental diagnosis with identification and description of its mains consequences. The result of this work was the delineation of geologic-geomorphological map of the area with identification of principals units, determining its use and occupation, the measurement of the area already occupied by equipments, besides the description of the environmental impacts on dune fields: devastation, coastline erosion, ocean pollution by sewer and pluvial waters, contamination of groundwater, distribution inadequate of solid residues, landscape degradation, and occupation of seashore through the privatization of public areas. Concluding that the degrading changes occurred in this areas are resulting from the nature of use and urban seashore regulations, which have been diminishing the natural aspect, altering the landscape definitely, compromising the quality of hydro resources and altering its use, privatizing the areas between tides, complicating the population access and obstructing the scenery visualization of dunes and ocean. There is an urgent necessity of improvement of public politics in order to improve the strategies and organization of use and occupation of space urban-coastline

O ensino de língua inglesa em um instituto federal : uma análise das recomendações documentais e da perspetiva dos professores

This work aims to understand the teaching of English at the Federal Institute of considering the recommendations of official and technical documents for the integrated secondary school and the perspective of the English teachers settled in one of the campuses of the Institute. It is also an objective of this research to infer as to what extent the perspective of teachers is articulated to the documental recommendations. For this purpose, several official and technical documents (LÜDKE; ANDRÉ, 1986), such as the PCNEMs (BRAZIL, 2000), the OCNEMs (BRAZIL, 2006) and the Political-Pedagogical Project of the Institute (IFRN, in press) were gathered, and a questionnaire was submitted to six teachers of English from one of the campuses of the institution. The theoretical references of the research include, among others, Bakhtin (1997; 1999), Widdowson (1991), Almeida Filho (2011; 2004), Celani (1988; 2009), Hutchinson and Waters (1987) and Dudley-Evans and St. John (1998). The results show that the teaching of English according to the documents predicts the instrumental use of the foreign language, but suggests the development of competences and skills as contextualized social practices, aimed at the education of the student as a professional-citizen. The perspective of teachers, in turn, points to a concern that the teaching of English serves as a tool for improving student life through the instrumental use of language as a means of accessing information and professional training. This finding reveals that the articulation between the documental recommendations and perspective of teachers does not go beyond what refers to the instrumental language teaching, since teachers do not show, when reporting their practices, the teaching of language as social practice, as mentioned in the legal texts

"Eu pensei que ia sair daqui falando inglês": um estudo sistêmico-funcional sobre papéis sociais atribuídos por alunos de um curso de Letras/Inglês

Research in the area of teacher training in English as a Foreign Language (CELANI, 2003, 2004, 2010; PAIVA, 2000, 2003, 2005; VIEIRA-ABRAHÃO, 2010) articulates the complexity of beginning teachers classroom contexts aligned with teaching language as a social and professional practice of the teacher in training. To better understand this relationship, the present study is based on a corpus of transcribed interviews and questionnaires applied to 28 undergraduate students majoring in Letters/English emphasis, at a public university located in the interior of the Western Amazon region, soliciting their opinions about the reforms made in the curriculum of this Major. Interviews and questionnaires were used as data collection instruments to trace a profile of the students organized in Group 1, with freshmen and sophomore undergraduates who are following the 2009 curriculum, and Group 2, with junior and senior undergraduates who are following the 2006 curriculum. The objectives are to identify, to characterize and to analyze the types of pronouns, roles and social actors represented in the opinions of these students in relation to their teacher training curriculum. The theoretical support focuses on the challenge of historical and contemporary routes from English teachers initial education programs (MAGALHÃES; LIBERALLI, 2009; PAVAN; SILVA, 2010; ALVAREZ, 2010; VIANA, 2011; PAVAN, 2012). Our theoretical perspective is based on the Systemic Functional Grammar of Halliday (1994), Halliday and Hasan (1989), Halliday and Matthiessen (2004), Eggins (1994; 2004) and Thompson (2004). We focus on the concept of the Interpersonal meaning, specifically regarding the roles articulated in the studies by Delu (1991), Thompson and Thetela (1995), and in the Portuguese language such as Ramos (1997), Silva (2006) and Cabral (2009). Moreover, we ascribe van Leeuwen s (1997; 2003) theory of Representation of Social Actors as a theoretical framework in order to identify the sociological aspect of social actors represented in the students discourse. Within this scenario, the analysis unfolds on three levels: grammatical (pronouns), semantic (roles), and discursive (social actors). For the analysis of interpersonal realizations present in the students opinions, we use the computational program WordSmith Tools (SCOTT, 2010) and its applications Wordlist and Concord to quantify the occurrences of the pronouns I, You and They, which characterize the roles and social actors of the corpus. The results show that the students assigned the following roles to themselves: (i) apprentice to express their initial process of English language learning; (ii) freshman to reveal their choice of Major in Letters/English emphasis; (iii) future teacher to relate their expectations towards a practicing professional. To assign the roles to professors in the major, the students used the metaphor of modality (I think) to indicate the relationship of teacher training, while they are in the role of a student and as a future teacher. From these evidences the representation of the students as social actors emerges in roles such as: (i) active roles; (ii) passive roles and (iii) personalized roles. The social actors represented in the opinions of the students reflect the inclusion of these roles assigned to the actions expressed about their experiences and expectations derived from their teacher training classroom

Produção em revista : Representação do moderno e do regional na experiência potiguar anos 1920

This work brings some reading about a few Norte-rio-grandenses writers collaborations published in literary papers which circulated during the third decade of the twentieth century in Brazil, in a way of enlarging the understanding of how the cultural debate was carried out in the years of the definition of the Brazilian Modernism, based on the relationships between literature and culture. Under the genres of prose and poetry, the selected textual collaborations for analysis have brought the traces of a small group of articulated authors in the Brazilian cultural scenery from the 1920 s, concerning the issues of the modern (linked to the modernist renovation) and the regional (under the aspects of the tradition). The set of the analyzed collaborations is representative of a modern-regional cultural practice marked by a tendency either local or cosmopolitan, thus, sharing a large dimension of the formation of the modern literary tradition, marked by different kinds of practices which give form to the project of a collective national awareness. The characterization of the existence of an intellectual field with big links, however with its own characteristics and a certain autonomy, which also gets integrated to the cultural debate of the so-called modernist years through the literary vehicles, gives to these intellectual people a co-participation in the renewing movement in the formation context of the brazilian cultural modernity of the early twentieth century

Os argumentos transcendentais: kant e o problema de hume

This work whose title is "The transcendental arguments: Kant Andy Hume's problem" has as its main objective to interpret Kant's answer to Hume's problem in the light of the conjunction of the causality and induction themes which is equivalent to skeptical- naturalist reading of the latter. In this sense, this initiative complements the previous treatment seen in our dissertation, where the same issue had been discussed from a merely skeptical reading that Kant got from Hume thought and was only examined causality. Among the specific objectives, we list the following: a) critical philosophy fulfills three basic functions, a founding, one negative and one would argue that the practical use of reason, here named as defensive b) the Kantian solution of Hume's problem in the first critisism would fulfill its founding and negative functions of critique of reason; c) the Kantian treatment of the theme of induction in other criticisms would will fulfill the defense function of critique of reason; d) that the evidence of Kant's answer to Hume's problem are more consistent when will be satisfied these three functions or moments of criticism. The basic structure of the work consists of three parts: the first the genesis of Hume's problem - our intention is to reconstruct Hume's problem, analyzing it from the perspective of two definitions of cause, where the dilution of the first definition in the second match the reduction of psychological knowledge to the probability of following the called naturalization of causal relations; whereas in the second - Legality and Causality - it is stated that when considering Hume in the skeptic-naturalist option, Kant is not entitled to respond by transcendental argument A􀁴B; A⊢B from the second Analogy, evidence that is rooted in the position of contemporary thinkers, such as Strawson and Allison; in third part - Purpose and Induction - admits that Kant responds to Hume on the level of regulative reason use, although the development of this test exceeds the limits of the founding function of criticism. And this is articulated in both the Introduction and Concluding Remarks by meeting the defensive [and negative] function of criticism. In this context, based on the use of so-called transcendental arguments that project throughout the critical trilogy, we provide solution to a recurring issue that recurs at several points in our submission and concerning to the "existence and / or the necessity of empirical causal laws. In this light, our thesis is that transcendental arguments are only an apodictic solution to the Hume s skeptical-naturalist problem when is at stake a practical project in which the interest of reason is ensured, as will, in short, proved in our final considerations

Sujeito e liberdade no pensamento de Michel Foucault

The leitmotif of this dissertation research is on the relationship between two fields of questioning in the Foucauldian works that may be considered, at a first glance, irreconcilable: the understanding of subject as the result of determinations, on the one hand, and its ethical stance of seeking the creation of liberty, on the other. Since, despite this apparent inconsistency, both ideas are present with much emphasis on the work of the French thinker, to understand the way Foucault articulated these two ideas was necessary to elucidate and interrelate the way in which he thought about the concepts of subject, power and liberty. Traveling with the author his intellectual itinerary, it was revealed that his conception of subject and liberty can be reconciled (although maintaining its problematic nature) and, also, both are inextricably linked each one as a result of the other. Tracing, with the author, his intellectual itinerary, it was also possible to identify and describe the fruitful conceptual tools for thinking about our own determinations and about the possibilities we have of creating new subjectivities and liberating experiences

Luís Natal ou Câmara Cascudo: o autor da cidade e o espaço como autoria

The objective of this work is to problematize a strong identification of Luís da Câmara Cascudo (1898-1986), a norte-riograndense author, to the city of Natal, analyzing the constitution of a spaciality that takes this author as this city s intellectual exponent and cultural monument, which I name as Natal cascudiana. In this sense, I investigate the process of Câmara Cascudo s monumentalization by the city of Natal, questioning the way his life has been articulated to the site of his production. Bearing this in mind, I have structured the work in three parts: on the first one, I examine the emerging of this identity relationship considering the intellectual formation of young Cascudinho and the beginnings of his literary activities, verifying the reasons that led him to remain in Natal; on the second part I investigate his appointment as Natal s historian in 1948, discussing the ways through which this intellectual function institutionalized the works of Cascudo and conferred the city with a historical knowledge of itself; and finally, I analyze the constitution of a city memory regarding Cascudo, that has transformed him into spatial marks and urban toponym: names of streets, museum, library, bookstores etc. On these terms, I deal with the biographic gender to achieve a history of the city s spaces, problematizing the monumentalization of Cascudo in Natal, interrogating the emerging of this Natal cascudiana

A escrita do tempo e a poética do espaço:história e espaço no livro Geografia do Brasil Holandês de Luís da Câmara Cascudo

In 1956, Luís da Câmara Cascudo published his book Geografia do Brasil Holandês. In this book, he studied and described a space - the Dutch Brazil - from a geographical and historical perspective. To do this, he articulated both perspectives from the point of view of his own reading of the History of Nordeste , establishing a dialogue with the historiographical tradition of the study of the Dutch Brazil in Pernambuco. When portraying the Dutch presence in Nordeste, Cascudo articulated a drama in which the Dutch would have their history described as a typically tragic plot, portrayed as if they were already condemned to failure in advance. To this tragedy he opposed a predominantly comic Portuguese plot, as if the Portuguese victory over the Dutch was as desirable as inevitable for the space of Nordeste . When narrating the clash between the Dutch and the Portuguese for the space of Nordeste , however, Cascudo ended up delineating his own place of speech, as a spokesperson for the identity of the potiguar space in opposition to the pernabucano space described by Freyre and Gonsalves de Mello. In this way, the space of Rio Grande do Norte would have its own identity, constructed from de Dutch absence and constituted from the Portuguese legacy contrarily to the space of Pernambuco, narrated from an articulation and a conciliation of the Flemish and Lusitan legacy, even though highlighting the latter. While the Dutch would had been a constant presence in the history of Pernambuco for Freyre and Gonsalves de Mello, they wouldn t have gone beyond legend in the space of Rio Grande do Norte, removed from its geography and erased from its history. When describing de geography of the potiguar space, therefore, Cascudo articulates the inexistence of the History of a time dominated by the Fleming with the search of a Portuguese space, trough the narration of its origins and constitution, as well as the registry of the characteristics of its legacy