71 resultados para Fusão alcalina
Resumo:
This thesis aimed to assess the increase in solubility of simvastatin (SINV) with solid dispersions using techniques such as kneading (MA), co-solvent evaporation (ES), melting carrier (FC) and spray dryer (SD). Soluplus (SOL), PEG 6000 (PEG), PVP K-30 (PVP) e sodium lauryl sulphate (LSS) were used as carriers. The solid dispersions containing PEG [PEG-2(SD)], Soluplus [SOL-2(MA)] and sodium lauryl sulphate [LSS-2(ES)] were presented with a greater increase in solubility (5.02, 5.60 and 5.43 times respectively); analyses by ANOVA between the three groups did not present significant difference (p<0.05). In the phase solubility study, the calculation of the Gibbs free energy (ΔG) revealed that the spontaneity of solubilisation of SINV occurred in the order SOL>PEG >PVP 75%>LSS, always 80%. The phase diagrams of PEG and LSS presented solubilization stoichiometry of type 1:1 (type AL). The diagrams with PVP and SOL tend to 1:2 stoichiometry (type AL + AP). The stability coefficients (Ks) of the phase diagrams revealed that the most stable reactions occurred with LSS and PVP. The solid dispersions were characterized by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), particle size distribution (PSD), near-infrared spectroscopy imaging (NIR-CI) and X-ray diffraction of the powder using the Topas software (PDRX-TOPAS). The solid dispersion PEG-2(SD) presented the greatest homogeneity and the lowest degree of crystallinity (18.2%). The accelerated stability study revealed that the solid dispersions are less stable than SINV, with PEG-2(SD) being the least stable, confirmed by FTIR and DSC. The analyses by PDRX-TOPAS revealed the amorphous character of the dispersions and the mechanism of increasing solubility
Resumo:
This research, whose theme is related to climacteric, aims to know the social representation of menopause developed by the nurses working for Estratégia Saúde da Família (Family Health Strategy) in João Pessoa PB, as well as identifying its structure and verifying the way it interferes with the assistance and educational practices to the climacterial user. In the theoretical level, it is based on a model that articulates the social representations theory, the central nucleus complementary theory and the central concepts of Pierre Bourdieu s praxiology: habitus, cultural capital, social field and symbolic power. A hundred and forty-seven female nurses who work for Estratégia Saúde da Família (Family Health Strategy) in João Pessoa (PB) took part in this research, and the data collection period was from February 2008 to March 2009. As to the methods and techniques, we used the method to determine the central nucleus based on the free association of words, a questionnaire to identify certain regularities that constitute the nurses habitus, and the semi-structured interview to explore opinions and attitudes when facing assistance situations and educational practices and to collect other relevant information. The data analysis was developed, when referring to the free associations, with the help of the EVOC software, which is a group of articulated programs which carry out the statistical analysis of the evocations and the identification of the possible elements of both the central nucleus and the peripheral system of the social representation. As to the questionnaire, we used the descriptive statistical analysis and the analysis of correlation between the variables. The interviews were submitted to a categorical analysis of the content. The EVOC result indicated that the cognition hormone was the only element of the central nucleus of the social representation of menopause. Due to its symbolic value and structuring power, this central nucleus ensures the strict and, at the same time, flexible character of the representational content. The analysis of the social advancement, of some fundamental features of the group habitus, as well as the analysis of its insertion in the health field and of the attitudinal opinions and dispositions concerning the assistance given to the climacterial user, and the analysis of the pedagogical dimension of this assistance, all these analyses lead to the conclusion that the nurses who took part in this research share a social representation of the menopause resulting from the association of different technical and scientific knowledge. These derive from the biomedical pattern as well as from hegemonic values which disqualify old age and overvalue youth, from pedagogical conceptions arising from patterns that are presently regarded as authoritative and old-fashioned and from cultural references (responsible for the semantic variations concerning the central nucleus) which are specific to the subgroups the nurses belong to. This research enables the creation of opportunities for discussion between active nurses working for Estratégia Saúde da Família, and the nurses who are teachers at institutions of higher education, aiming at linking theory to practice, so that they can find ways of thinking about the climacteric and working, in a more comprehensive way, with users who are experiencing this stage of life
Resumo:
We present here the results of a study whose objectives were to identify the social representation of being a professor of early childhood education in Campina Grande - PB, in the public state and municipal levels, and detect structural diagrams of a possible mental habitus of professorial faculty of education child, which would form the basis for the construction of this representation. As a theoretical base, we adopted the model developed by Domingos Sobrinho (1998, 2000, 2003, 2010, 2011), which articulates the Theory of Social Representations, Serge Moscovici, and the foundations and concepts of Pierre Bourdieu praxiology. It is based also on the Central Nucleus Theory, which focuses on the structural approach of social representations. Thus, puts in evidence the relational dynamics and symbolic, through which individuals come into contact, describe, understand and reproduce the outside world in his image and likeness. 199 teachers participated in the study of child care and pre-schools of Campina Grande - PB and 109 of the state. The methods and techniques used were: a) participant observation of everyday life of teachers of kindergartens and preschools, b) semi-structured interview, c) free associations of words with inducing the expression 'being a professor of early childhood education is ...' and d) semi-structured questionnaire. The data were analyzed in the case of interviews through the categorical content analysis, as proposed by Bauer (2010); free-associations, using the software Ensemble L'Analyse des Programmes Permettant evocations (EVOC), developed by Vergès (2002), which combines frequency and average order of recall (or association) and the questionnaire data, the Statistical Package for the Social Sciences (SPSS). It was verified the existence of a unique social representation shared by the population studied, but its content is structured differently. For local teachers, the centrality of the content is given by the elements commitment, dedication, responsibility, and rewarding teachers for this state revolves around the elements of love, patience, and rewarding responsibility. However, it is constructed mainly based on the related produced by a religious habitus and maternal habitus, which are part of the genesis of the establishment of professorial habitus in focus, among other cultural references of secondary influence. We conclude that a teacher of early childhood education actually researched, is materialized in the practices of educating and caring, in a clear fusion of the role of teacher and mother
Resumo:
The desire to research on this subject arisen from the experience as nursing in the indigenous health, where I observed that many professionals from all regions of Brazil chose to work within this zone. It was notorious the nurse s difficult to settle in only one place for a long length of time. Probably due to health care in indigenous zones happens from a cultural confront. This confront materialize because both sides are imbued with their own culture: in one hand the nurse professional with its scientific knownledgment on the other the indigenous with their rituals and peculiars habits. In this context nurses should delineate and negotiate the reality through symbolic representations of life, and then make questions on the new reality. In this way, this study set out with the aim of apprehends the nurse s social representations of transcultural care in indigenous health. This knownledgment is important to avoid possible conflicts, shocks, difficulties and health care incongruence within this context. The data collect was carried out on a range of non structured interview guided by a pre-elaborated questionnaire with four questions and a hand drawing related to nurse s health care in the indigenous health. This research had a sample of 17 nurses from the Indigenous Sanitary District of Manaus in the Amazon State. To interpret data we used the Discourse of the Collective Subject, which findings were presented in three chapters: characterization of participants, discussion on themes prevalent in discourse; social representation of nursing care through infographics. The analysis revealed that the care in the indigenous health is challenging because the native people imbued in its world are perceived and processed according to the nurse s cultural lens, leading to materialize of some strangeness and adaptation difficulties, especially in the first contacts. The Social Representation on nursing practice, in many cases, is projected and contrived on the basis of scattered believes and on perception derived from common sense. The findings shows that representions are essential to mitigating the initial strangeness and help nurses to better situate themselves in the new universe. The nurse s practice in the indigenous health care should merge into each other. From the Social Representations is possible to perceive that assimilation, also comprehension on indigenous health system and its traditional knowledge are important to developing strategies to improve access and quality of care for indigenous peoples. After analysis the nurse s discourses and drawings, it is possible to represent the nurse s practice in the indigenous health as anthropophagism, since nurses should literally consuming its patients culture, digesting it and seize it as means to provide culturally congruent care. We highlight the urgent need for preparation and training of professionals to work more effectively with indigenous peoples
Resumo:
This work presents the localization and path planning systems for two robots: a non-instrumented humanoid and a slave wheeled robot. The localization of wheeled robot is made using odometry information and landmark detection. These informations are fused using a Extended Kalman Filter. The relative position of humanoid is acquired fusing (using another Kalman Filter) the wheeled robot pose with the characteristics of the landmark on the back of humanoid. Knowing the wheeled robot position and the humanoid relative position in relation to it, we acquired the absolute position of humanoid. The path planning system was developed to provide the cooperative movement of the two robots,incorporating the visibility restrictions of the robotic system
Resumo:
This work presents a cooperative navigation systemof a humanoid robot and a wheeled robot using visual information, aiming to navigate the non-instrumented humanoid robot using information obtained from the instrumented wheeled robot. Despite the humanoid not having sensors to its navigation, it can be remotely controlled by infra-red signals. Thus, the wheeled robot can control the humanoid positioning itself behind him and, through visual information, find it and navigate it. The location of the wheeled robot is obtained merging information from odometers and from landmarks detection, using the Extended Kalman Filter. The marks are visually detected, and their features are extracted by image processing. Parameters obtained by image processing are directly used in the Extended Kalman Filter. Thus, while the wheeled robot locates and navigates the humanoid, it also simultaneously calculates its own location and maps the environment (SLAM). The navigation is done through heuristic algorithms based on errors between the actual and desired pose for each robot. The main contribution of this work was the implementation of a cooperative navigation system for two robots based on visual information, which can be extended to other robotic applications, as the ability to control robots without interfering on its hardware, or attaching communication devices
Resumo:
A hierarchical fuzzy control scheme is applied to improve vibration suppression by using an electro-mechanical system based on the lever principle. The hierarchical intelligent controller consists of a hierarchical fuzzy supervisor, one fuzzy controller and one robust controller. The supervisor combines controllers output signal to generate the control signal that will be applied on the plant. The objective is to improve the performance of the electromechanical system, considering that the supervisor could take advantage of the different techniques based controllers. The robust controller design is based on a linear mathematical model. Genetic algorithms are used on the fuzzy controller and the supervisor tuning, which are based on non-linear mathematical model. In order to attest the efficiency of the hierarchical fuzzy control scheme, digital simulations were employed. Some comparisons involving the optimized hierarchical controller and the non-optimized hierarchical controller will be made to prove the efficiency of the genetic algorithms and the advantages of its use
Resumo:
Thermal insulation is used to protect the heated or cooled surfaces by the low thermal conductivity materials. The rigid ricin polyurethane foams (PURM) are used for thermal insulation and depend on the type and concentration of blowing agent. Obtaining PURM occurs by the use of polyol, silicone, catalyst and blowing agent are pre -mixed, reacting with the isocyanate. The glass is reusable, returnable and recyclable heat insulating material, whose time of heat dissipation determines the degree of relaxation of its structure; and viscosity determines the conditions for fusion, operating temperatures, annealing, etc. The production of PURM composites with waste glass powder (PV) represents economical and renewable actions of manufacturing of thermal insulating materials. Based on these aspects, the study aimed to produce and characterize the PURM composites with PV, whose the mass percentages were 5, 10, 20, 30, 40 and 50 wt%. PURM was obtained commercially, while the PV was recycled from the tailings of the stoning process of a glassmaking; when the refining process was applied to obtain micrometer particles. The PURM + PV composites were studied taking into account the standard sample of pure PURM and the influence of the percentage of PV in this PURM matrix. The results of the chemical, physical and morphological characterization were discussed taking into account the difference in the microstructural morphology of the PURM+PV composites and the pure PURM, as well the results of the physicochemical, mechanical e thermophysical tests by values obtained of density, hardness, compressive strength, specific heat, thermal conductivity and diffusivity. In general, the structure of pure PURM showed large, elongated and regular pores, while PURM+PV composites showed irregular, small and rounded pores with shapeless cells. This may have contributed to reducing their mechanical strength, especially for PURM - PV50. The hardness and density were found to have a proportional relationship with the PV content on PURM matrix. The specific heat, thermal diffusivity and thermal conductivity showed proportional relationship to each other. So, this has been realized that the increasing the PV content on PURM matrix resulted in the rise of diffusivity and thermal conductivity and the decrease of the specific heat. However, the values obtained by the PURM composites were similar the values of pure PURM, mainly the PURM-PV5 and PURM-PV10. Therefore, these composites can be applied like thermal insulator; furthermore, their use could reduce the production costs and to preserve the environment
Resumo:
In machining of internal threads, dedicated tools, known as taps, are needed for each profile type, diameter, and low cutting speed values are used when compared to main machining processes. This restriction in the cutting speed is associated with the difficulty of synchronizing the tool s rotation speed and feed velocity in the process. This fact restricts the flexibility and makes machining lead times longer when manufacturing of components with threads is required. An alternative to the constraints imposed by the tap is the thread milling with helical interpolation technique. The technique is the fusion of two movements: rotation and helical interpolation. The tools may have different configurations: a single edge or multiple edges (axial, radial or both). However, thread milling with helical interpolation technique is relatively new and there are limited studies on the subject, a fact which promotes challenges to its wide application in the manufacturing shop floor. The objective of this research is determine the performance of different types of tools in the thread milling with helical interpolation technique using hardened steel workpieces. In this sense, four tool configurations were used for threading milling in AISI 4340 quenched and tempered steel (40 HRC). The results showed that climb cut promoted a greater number of machined threads, regardless of tool configuration. The upcut milling causes chippings in cutting edge, while the climb cutting promotes abrasive wear. Another important point is that increase in hole diameter by tool diameter ratio increases tool lifetime
Resumo:
The segment of the structural ceramics industry is one of the most important to the economy of Rio Grande do Norte. The supply chain makes a total of 206 companies that are distributed in 39 counties, concentrated in three regional centers: Seridó Apodi / Assu and great Natal. The ceramic industry in the state is around 80 million pieces per month, with 50,186 million of these tiles, which makes the Rio Grande do Norte one of the largest manufacturers of product in the Country. Different ceramic products can be manufactured by mixing two or more clays and accessory minerals. Mixtures acquire characteristics and form what is called the ceramic body. Refractory masses have a high melting point and thermal shock support. Its composition contains refractory clays with a little iron oxide and material fluxes. A line of semi-refractory ceramic products that stands out for its high added value are the bricks in ivory or red, used in building barbecues, fireplaces, wood stoves and braziers. The aim of this study was to use alumina-clay or silica- alumina-clay to the industrial RN, for the production of refractory bricks semi-refractory burning light. Clay and Kaolin were characterized for their chemical and mineralogical composition, immediately after ceramic bodies were made with different concentrations of the components, they were raised, pressed and sintered. After sintering the resulting products were characterized in terms of mechanical, thermal and dimensional than the characterization by X-ray diffraction and scanning electron microscopy. After obtaining the results, we concluded that the studied clay can be used for the production of semi-refractory bricks
Resumo:
The constant search for biodegradable materials for applications in several fields shows that carnauba wax can be a viable alternative in the manufacturing of biolubricants. Carnauba wax is the unique among the natural waxes to have a combination of properties of great importance. In previous studies it was verified the presence of metals in wax composition that can harm the oxidative stability of lubricants. Considering these factors, it was decided to develop a research to evaluate iron removal from carnauba wax, using microemulsion systems (Me) and perform the optimization of parameters, such as: extraction pH, temperature, extraction time, among others. Iron concentration was determined by atomic absorption and, to perform this analysis, sample digestion in microwave oven was used, showing that this process was very efficient. It was performed some analysis in order to characterize the wax sample, such as: attenuated total reflectance infrared spectroscopy (ATR-IR), thermogravimetry (TG), differential scanning calorimetry (DSC), energy dispersive X-ray fluorescence (EDXRF), scanning electron microscopy (SEM) and melting point (FP). The microemulsion systems were composed by: coconut oil as surfactant, n-butanol as cosurfactant, kerosene and/or heptanes as oil phase, distilled water as water phase. The pH chosen for this study was 4.5 and the metal extraction was performed in finite experiments. To evaluate Me extraction it was performed a factorial design for systems with heptane and kerosene as oil phase, also investigating the influence of temperature time and wax/Me ratio, that showed an statistically significant answer for iron extraction at 95% confidence level. The best result was obtained at 60°C, 10 hours contact time and 1: 10 wax/Me ratio, in both systems with kerosene and heptanes as oil phase. The best extraction occurred with kerosene as oil phase, with 54% iron removal
Resumo:
The need for new sources of energy and the concern about the environment have pushed the search for renewable energy sources such as ethanol. The use of lignocellulosic biomass as substrate appears as an important alternative because of the abundance of this raw material and for it does not compete with food production. However, the process still meets difficulties of implementation, including the cost for production of enzymes that degrade cellulose to fermentable sugars. The aim of this study was to evaluate the behavior of the species of cactus pear Opuntia ficus indica and Nopalea cochenillifera, commonly found in northeastern Brazil, as raw materials for the production of: 1) cellulosic ethanol by simultaneous saccharification and fermentation (SSF) process, using two different strains of Saccharomyces cerevisiae (PE-2 and LNF CA-11), and 2) cellulolytic enzymes by semi-solid state fermentation (SSSF) using the filamentous fungus Penicillium chrysogenum. Before alcoholic fermentation process, the material was conditioned and pretreated by three different strategies: alkaline hydrogen peroxide, alkaline using NaOH and acid using H2SO4 followed by alkaline delignification with NaOH. Analysis of composition, crystallinity and enzymatic digestibility were carried out with the material before and after pretreatment. In addition, scanning electron microscopy images were used to compare qualitatively the material and observe the effects of pretreatments. An experimental design 2² with triplicate at the central point was used to evaluate the influence of temperature (30, 40 and 45 °C) and the initial charge of substrate (3, 4 and 5% cellulose) in the SSF process using the material obtained through the best condition and testing both strains of S. cerevisiae, one of them flocculent (LNF CA-11). For cellulase production, the filamentous fungus P. chrysogenum was tested with N. cochenillifera in the raw condition (without pretreatment) and pretrated hydrothermically, varying the pH of the fermentative medium (3, 5 and 7). The characterization of cactus pear resulted in 31.55% cellulose, 17.12% hemicellulose and 10.25% lignin for N. cochenillifera and 34.86% cellulose, 19.97% hemicellulose and 15.72% lignin for O. ficus indica. It has also been determined, to N. cochenillifera and O. ficus indica, the content of pectin (5.44% and 5.55% of calcium pectate, respectively), extractives (26.90% and 9.69%, respectively) and ashes (5.40% and 5.95%). Pretreatment using alkaline hydrogen peroxide resulted in the best cellulose recovery results (86.16% for N. cochenillifera and 93.59% for O. ficus indica) and delignification (48.79% and 23.84% for N. cochenillifera and O. ficus indica, respectively). This pretreatment was also the only one which did not increase the crystallinity index of the samples, in the case of O. ficus indica. However, when analyzing the enzymatic digestibility of cellulose, alkali pretreatment was the one which showed the best yields and therefore it was chosen for the tests in SSF. The experiments showed higher yield of conversion of cellulose to ethanol by PE-2 strain using the pretreated N. cochenillifera (93.81%) at 40 °C using 4% initial charge of cellulose. N. cochenillifera gave better yields than O. ficus indica and PE-2 strain showed better performance than CA-11. N. cochenillifera proved to be a substrate that can be used in the SSSF for enzymes production, reaching values of 1.00 U/g of CMCase and 0.85 FPU/g. The pretreatment was not effective to increase the enzymatic activity values
Resumo:
The WAT is the temperature at the beginning of the appearance of wax crystals. At this temperature the first wax crystals are formed by the cooling systems paraffin / solvents. Paraffins are composed of a mixture of saturated hydrocarbons of high molecular weight. The removal of petroleum from wells and the production lines means a surcharge on produced oil, thus solubilize these deposits formed due to modifications of thermodynamics has been a constant challenge for companies of oil exploration. This study combines the paraffin solubilization by microemulsion systems, the determination of WAT systems paraffin / solvent and performance of surfactant in reducing the crystallization. We used the methods: rheological and the photoelectric signal, validating the latter which was developed to optimize the data obtained due to sensitivity of the equipment used. Methods developed for description of wax precipitation are often in poor agreement with the experimental data, they tend to underestimate the amount of wax at temperatures below the turbidity point. The Won method and the Ideal solution method were applied to the WAT data obtained in solvent systems, best represented by the second interaction of Won method using the solvents naphtha, hexane and LCO. It was observed that the results obtained by WAT photoelectric signal when compared with the viscosity occur in advance, demonstrating the greatest sensitivity of the method developed. The ionic surfactant reduced the viscosity of the solvent systems as it acted modifying the crystalline structure and, consequently, the pour point. The curves show that the WAT experimental data is, in general, closer to the modeling performed by the method of Won than to the one performed by the ideal solution method, because this method underestimates the curve predicting the onset of paraffin hydrocarbons crystallization temperature. This occurs because the actual temperature measured was the crystallization temperature and the method proposes the fusion temperature measurement.
Resumo:
The present work aims to report the construction of a workbook for teaching trigonometry focusing the possible mix between the historical approach to the teaching of mathematics and the professional master´s degree. For this, considerations about the history of mathematics as a teaching methodology, the education of the math teacher who will teach trigonometry and also about the course of elaboration and experimentation of the activities in the workbook were made (using the methodological strategy of action research). Finally, the workbook for the teaching of trigonometry in a historical approach is presented as an example of the above mentioned mix between the history of mathematics, mathematical school content and the professional master´s degree
Resumo:
A abordagem da visão da literatura nacional dentro do contexto cultural brasileiro da segunda metade do século XIX e do posicionamento crítico de José de Alencar fez, de sua produção romanesca, especialmente a indianista, representada aqui por sua obra Iracema, um símbolo do conjunto de intenções nacionalistas que invadiu a alma e o coração de todo o povo, no que diz respeito ao sentimento de brasilidade , condizente com a estética romântica da qual faz parte seu autor. Seu posicionamento, quer seja crítico ou artístico, faz de Alencar o maior polemista em defesa da liberdade cultural e literária do Brasil, enquanto alguém bem consciente de sua função social, e por que não dizer, crítica, identificando a metalinguagem como um diferencial fomentador de uma teorização de poética na defesa de sua ficção, abrindo caminho, assim, para a pesquisa da poética explícita na sua produção artística. A referida análise buscará, a partir de uma análise estrutural das partes formais que o compõem esteticamente, como também de uma compreensão temática dos ditos e interditos utilizados pelo narrador alencariano na composição de seu discurso, identificar Iracema enquanto um romance que disputa o título de obra fundacional do Brasil. Para isso se faz necessário empreender uma abordagem do como e do quanto os elementos da Natureza, num romance romântico que tem a Natureza enquanto uma de suas temáticas mais significativas, podem constituir e interferir na percepção e construção de um personagem, que é todo Natureza, e no meio natural em que ele vive; até mesmo ser, por causa disso, o elemento mais representativo dessa nação que se deseja criar, trazendo para o cenário cultural brasileiro do século XIX uma versão de instituição baseada no revigoramento da memória da cultura selvagem. Faz-se lícito também animar forças da natureza e da terra-paisagem que poderiam ser tidas, apenas, como exóticas, mas que na obra em questão funcionam como protagonistas, mesmo fantasmas, de um pacto social e político que, mesmo quando rompe, recusa-se em deixar romper, mergulhando no espaço romanesco da magnitude das águas ou na frieza tumular da terra. Tomar-se-á, também, como ponto de estudo, a análise da fusão da experiência histórica com a experiência ficcional, observando o imbricamento de um discurso no outro, como também as fronteiras que se estabelecem a partir dessa tentativa; tomando o erotismo e a alegoria como pontos de convergência na obra em questão. Por meio da verificação de uma relação que se constrói a partir da solidão, da memória e do esquecimento em que acabam por mergulhar todos os seus personagens, que são, por vezes, tragados em algum dilúvio bíblico da purificação, dentro de um projeto audacioso de invenção de uma nação, que se quer de identidade cultural, e também política, mas que termina condenado ao silêncio, não gozando de liberdade em relação ao espaço a que pertence e, no entanto representa, só cabendo a eles regressarem para dentro da terra-mãe, ou se submeterem a um ritual de profunda aculturação, verificar-se-á, através desse discurso historicamente construído, o ideário de uma nação que se almejava projetar. O conflito de Iracema, personagem protagonista de sua obra homônima, a negação e a perda de si mesma, de tudo aquilo que poderia representar a sua identidade social e cultural, e, conseqüentemente, a morte e a vida dessa mãe genti(o)l, simbolizam a vida e a arte de um povo que, passando pelos embates da colonização, através de seus artistas rebeldes e românticos da Independência, que ilustraram, em grande síntese, a visão através da qual o homem do Novo Mundo foi vislumbrado, rabiscou a imagem da americanidade pelo discurso da História