98 resultados para força de tração


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Researches have shown that the introduction of rubber in concrete improves the features of its deformability, as well as contributes to environmental disposal of waste generated in the tire retreading process. Furthermore, there is a high availability of limestone within RN and CE country. Ignorance about this stone, does not allow its wide use as aggregate, leaving, this abundant supply idle. A composite of limestone gravel, with proportions of tire rubber waste which could be used as concrete would be an alternative to concrete for low applications. Therefore, this research aims to evaluate the characteristics of concrete containing limestone gravel and proportions of little aggregate replacement (sand) by tire rubber waste. To this goal, the material components of the concrete were characterized, concrete specimens with limestone gravel were made, from the dash 1.0: 2.5: 3.5, varying the water/cement ratio, and inserting a commercial plasticizer, without a proportion of residue, known as reference. From this, concrete with and without the presence of the additive in the same proportions were chosen, as well as these with the use of granite gravel, for being the most used. Selected the references, to these, replacements of little aggregate (sand) were added replaced by rubber waste from the tire retreading process, treated with 1M NaOH in proportions from 5.0 to 20.0 % by mass, cured and exposed to the semiarid environment. The results indicate the possibility of using limestone gravel in the concrete composition with workability correction using plasticizer. There was a decrease in the mechanical properties of the concrete with increments of waste rubber, but there is an improvement in toughness and deformability of the composite, which makes it interesting for the construction of non-structural concrete floors, as well as, the rubber waste delayed the hardening process, continuing to gain resistance after 28 days

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As most current studies, reinforced plastics have been, in recent years, a viable alternative in building structural elements of medium and large, since the lightness accompanied by high performance possible. The design of hybrid polymer composites (combination of different types of reinforcements) may enable structural applications thereof, facing the most severe service conditions. Within this class of composite materials, reinforced the underlying tissues hybrid high performance are taking space when your application requires high load bearing and high rigidity. The objective of this research work is to study the challenges in designing these fabrics bring these materials as to its mechanical characterization and fracture mechanisms involved. Some parameters associated with the process and / or form of hybridization stand out as influential factors in the final performance of the material such as the presence of anisotropy, so the fabric weave, the process of making the same, normative geometry of the specimens, among others. This sense, four laminates were developed based hybrid reinforcement fabrics involving AS4 carbon fiber, kevlar and glass 49-E as the matrix epoxy vinyl ester resin (DERAKANE 411-350). All laminates were formed each with four layers of reinforcements. Depending on the hybrid fabric, all the influencing factors mentioned above have been studied for laminates. All laminates were manufactured industrially used being the lamination process manual (hand-lay-up). All mechanical characterization and study of the mechanism of fracture (fracture mechanics) was developed for laminates subjected to uniaxial tensile test, bending in three and uniaxial compression. The analysis of fracture mechanisms were held involving the macroscopic, optical microscopy and scanning electron microscopy

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This thesis has as objective presents a methodology to evaluate the behavior of the corrosion inhibitors sodium nitrite, sodium dichromate and sodium molybdate, as well as your mixture, the corrosion process for the built-in steel in the reinforced concrete, through different techniques electrochemical, as well as the mechanical properties of that concrete non conventional. The addition of the inhibitors was studied in the concrete in the proportions from 0.5 to 3.5 % regarding the cement mass, isolated or in the mixture, with concrete mixture proportions of 1.0:1.5:2.5 (cement, fine aggregate and coarse aggregate), superplasticizers 2.0 % and 0.40 water/cement ratio. In the modified concrete resistance rehearsals they were accomplished to the compression, consistence and the absorption of water, while to analyze the built-in steel in the concrete the rehearsals of polarization curves they were made. They were also execute, rehearsals of corrosion potential and polarization resistance with intention of diagnose the beginning of the corrosion of the armors inserted in body-of-proof submitted to an accelerated exhibition in immersion cycle and drying to the air. It was concluded, that among the studied inhibitors sodium nitrite , in the proportion of 2.0 % in relation to the mass of the cement, presented the best capacity of protection of the steel through all the studied techniques and that the methodology and the monitoring techniques used in this work, they were shown appropriate to evaluate the behavior and the efficiency of the inhibitors

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It is located in an area of increasing oil exploration, the region of the Lower Açu is at the mercy of a possible pollution generated by this economic activity, which includes various chemical substances harmful to health, such as metals. This thesis aims to, diagnose the areas of River Piranhas-Açu, a region of the Lower Açu, which are polluted by traces factors and more. In this study, it was determined the concentration of the chemica elements Al, CD, Cr, Cu, Fe, Mn, Ni, P, Pb, V and Zn, through the technique of ICP-OES analysis and the size of sediments and their contents organic matter. Were mapped by GPS, 12 points from collections. The interpretations of the results, together associating that allowed pollution to a possible contamination by oil activity. The results showed tha some regions have low concentrations of cadmium, lead, copper, manganese and zinc unable to promote damage to human health. However, there are places where the concentrations of certain metals chromium, iron and zinc are moderately polluted compared to the results with the reference values of literature and others that are highly polluted by iron. However, due to a greater number of wells in production in those locations, those higher concentrations, it can be suggested a possible influence of oi production in some areas with concentrations of chromium and lead are higher than the rest of the points of monitoring. Moreover, it is observed that the highest levels of metals found in sediment of finer texture and more organic matter content

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The seismic processing technique has the main objective to provide adequate picture of geological structures from subsurface of sedimentary basins. Among the key steps of this process is the enhancement of seismic reflections by filtering unwanted signals, called seismic noise, the improvement of signals of interest and the application of imaging procedures. The seismic noise may appear random or coherent. This dissertation will present a technique to attenuate coherent noise, such as ground roll and multiple reflections, based on Empirical Mode Decomposition method. This method will be applied to decompose the seismic trace into Intrinsic Mode Functions. These functions have the properties of being symmetric, with local mean equals zero and the same number of zero-crossing and extremes. The developed technique was tested on synthetic and real data, and the results were considered encouraging

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It is a Cross-sectional and multi-disciplinary study whose population selection was made by department of human resources (composed by a Manager, an Oncologist and a Psychologist) from the hospital where this research was realized. They also collaborated with important information about the work of that professionals in the hospital. We also counted on a Statistic who made study design calculating the sample and analyzing data. This research issued Evaluating health professionals anxiety levels who care for cancer terminally ill and their feelings about that work as well as identifying the factors which have influence on it. 100 health professionals from the Hospital which is a reference on cancer caring in Brazil situated in the city of Natal, state of Rio Grande do Norte, participated of this research. There was a sample loss of 21%. Data were collected through a questionnaire and State-Trait Anxiety Inventory (STAI). Results showed that 15% of the professionals have low State Anxiety levels, 70% Medium State Anxiety levels and 15% high State anxiety levels. The Number of Patients and Working in another Institution have interfered in the anxiety levels. Doctors and Nursing Assistants and Technicians have got the highest high State Anxiety percentage (25%). 73% of them declare to feel some sort of different behavior and/or feelings in caring for terminally ill. The most remarkable professionals feelings were Suffering and Sadness, and Terminally ill Children was the most difficult age group to care for. We conclude that work overload and having more than one job can interfere in professional stress levels and anxiety. Dealing with terminally ill, specially children one, can cause on the professionals psychological suffering. It s recommended the development of supporting and training strategies to reduce and/or to prevent Stress and Anxiety high levels

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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Neste trabalho procuramos estudar o fenômeno do bruxismo, definido como o ato de apertar e/ou ranger os dentes, hábito prejudicial à região orofacial relacionado a varáveis psicossociais. O bruxismo é frequentemente associado aos aspectos emocionais, entre os mais ressaltados, a ansiedade e o estresse, podendo implicar em alterações das estruturas orofaciais, modificações funcionais e inclusive com repercussões sociais. Deste modo, torna-se relevante evidenciar que a pesquisa foi desenvolvida, visando o contexto multidisciplinar, abrangendo a Fonoaudiologia, Odontologia e Psicologia. Objetivo: verificar associação entre bruxismo, ansiedade e as principais queixas referentes à função mastigatória. Método: participaram oitenta voluntários, divididos entre grupo com bruxismo (N=40) e sem bruxismo (N=40), do sexo masculino e feminino. O diagnóstico do bruxismo foi realizado através do exame clínico. Para avaliar os níveis de ansiedade empregou-se o Inventário de Ansiedade Traço e Estado e para os aspectos psicossociais um questionário com questões estruturadas referentes às atividades diárias, focando a função mastigatória (para o grupo com bruxismo). Resultados:: Os resultados permitem evidenciar diferenças significativas entre os grupos analisados, a média e desvio padrão de ansiedade estado no grupo com bruxismo, 42,7±9,6 e sem bruxismo 38,6±8,2 (p ≤0,04) e de ansiedade traço respectivamente 44,5±11,0 e controle 40,7±9,5 (p ≤0,11). O relato dos participantes com bruxismo evidenciou como principais queixas durante a mastigação, dor na face ao mastigar, cansaço muscular na face, cefaleia ao mastigar e presença de ruídos articulares. Conclusões: Evidenciamos uma associação dos fatores emocionais como a ansiedade e o bruxismo, e como resultante os pacientes apontam que a função mastigatória encontra-se depreciada

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Purpose: assess the frequency of stress and anxiety levels in infertile women, correlate these aspects with risk factors and qualitatively analyze feelings resultant from the inability to conceive, in order to obtain data for specific psychological guidance. Methods: the case-control study included a total of 302 women, 152 being infertile (case group: 30.3 ± 5.4 years), and 150 non-fertile (control group: 25.7 ± 7.9 years). The quantitative approach involved the application of Lipp s Stress Symptoms Inventory (LSSI) and State-Trait Anxiety Inventory (STAI), whereas the qualitative approach consisted of a semi-structured interview. Response variables considered were: stress frequency and anxiety scores (State and Trait). Statistical analysis compared frequencies and medians between groups, by means of qui-squared and Mann-Whitney tests, respectively, and constructed logistical regression models to test associations between response variables and risk factors considered. Qualitative data were analyzed descriptively and categorized in order to perform correspondence analysis. The level of significance was 5%. Results: in the study sample, stress frequency was higher in the case group than in the control(61.8 and 36.0%, respectively), however, significant differences were not observed between groups in relation to stress phases and predominant symptomology type. With respect to anxiety, there were no significant differences between case and control groups as to median state scores [39.5 (35.0 46.0) and 41.0 (35.7 47.0 ); respectively) and anxiety trait scores [44.0 (34.0 51.0) and 42.0 (36.0 49.2); respectively). Risk factors significantly associated with greater risk for high anxiety scores in the case group were: primary infertility, unawareness of the causal factor, diagnostic phase investigation, religion, lack of children from other marriages and the fact that the woman was previously married. The qualitative approach demonstrated that infertility provokes emotional responses, such as sadness, anxiety, anger, fear and guilt. Conclusions: it can be concluded that infertile women are more vulnerable to stress; however, they are capable of adapting to stressful events without serious physical or psychological compromising

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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This study aims to understand how facing a context of Constant interaction whit the local population, the gypsies family Alves dos Santos, neighborhood residentes in uptown, Limoeiro do Norte Ce, maintain a sense of ethnic belonging. To that end, I analyze both the social relations between Gypsies and non-gypsies community, as it is from the contact that the social boundaries are delineated, as the discourses and social representations that are used to qualify them from stigma. So, I found that grounded in the notion of family, gypsies are seen as a group, searching the history / past nomadic origing and blood common elements that underlie its condition, and the language a cultural trait that makes it possible to establish objective distinctions among gypsies and other community residentes, becoming thus a diacritical mark.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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An organisms movement within and between habitats is an essential trait of life history, one that shapes population dynamics, communities and ecosystems in space and time. Since the ability to perceive and react to specific conditions varies greatly between organisms, different movement patterns are generated. These, in turn, will reflect the way species persist in the original habitat and surrounding patches. This study evaluated patterns of movement of frugivorous butterflies in order to estimate the connectivity of a landscape mosaic in an area of Atlantic Forest. For this purpose, we used the capture-mark-recapture method on butterflies trapped with fermented fruit bait in three distinct habitats. The first represents a typical Atlantic forest fragment, while the other two represent man-made matrix habitats. One contains a coconut plantation and the other a plantation of the exotic Acacia mangium species. Five traps were randomly placed in each landscape unit in areas of 40 x 40m. Using recapture data and relating it to distance between captures and habitat structure, I found that movement frequencies, both within and between landscape units were different for the analyzed species, suggesting that they do not interpret and react to the landscape in the same way. Thus this study was able to measure landscape functional connectivity. For most species, the exchange between forest and coconut plantations occurred with low frequency compared to exchanges between the forest and acacia plantations, which share more structural similarities. This seems to indicate that a matrix that is more similar to patches of native vegetation can shelter species, permit their movement and, consequently, contribute to the landscape connectivity

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The present work has the intention to analyze the contribution of the writer and journalist Palmyra Guimarães Wanderley to the education, throughout her writings in the period between 1914 to 1920. I search through her journalist writings produced in the feminine magazine Via Láctea (1914-1915) her idealization, and as in the newspaper A República e Diário de Natal, in the decade of 1920 establishing relationships with education, mostly because of her production in the pages of the paper articles regarding feminine education and women condition. At the same time I sketch the biographic profile of Palmyra Wanderley relating her to the historical moment that she lived. To achieve the proposed goals I begin with a documental research within the available archives and use other sources like pictures and interviews with her relatives. The results of the research show that the worry of Palmira Wanderley with the education in our state, goes beyond her published writings in magazines and newspapers. She has been ahead of Escola de Comércio Feminino and Aliança Feminina, she has also done a conference in the House of the Young Single Ladies' Protection (Casa de Proteção às Moças Solteiras), institution of the Aliança s responsibility that offered shelter, food, formal and religious education to the workers of the Fabric Factory of Natal (Fábrica Tecidos de Natal). Her involvement evidences her contribution to the historiography of the education in Rio Grande do Norte, specially the history of women education ensuring her presence in the day by day history