168 resultados para Potencialização pós-ativação


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This dissertation of Mestrado investigated the performance and quality of web sites. The target of the research is the proposal of an integrated model of evaluation of services of digital information in web educational sites. The universe of the research was constituted by eighteen Brazilian Universities that offer after-graduation courses, in the levels of mestrado and doutorado in the area of Engineering of Production. The adopted methodology was a descriptive and exploratory research, using the technique of systematic comment and focus group, for the collection of the data, using itself changeable independent dependents and, through the application of two instruments of research. The analysis protocol was the instrument adopted for evaluation and attainment of qualitative results. E the analysis grating was applied for evaluation and attainment of the quantitative results. The qualitative results had identified to the lack of standardization of web sites, under the attributes of content, hierarchy of information, design of the colors and letters. It of accessibility for carriers of auditory and visual special necessities was observed inexistence, as well as the lack of convergence of medias and assistivas technologies. The language of the sites also was evaluated and all present Portuguese only language. The general result demonstrated in grafico and tables with classification of the Universities, predominating the Good note As for the quantitative results, analysis method ed was estatistico, in order to get the descriptive and inferencial result between the dependent and independent variaveis. How much a category of analysis of the services of the evaluated sites, was found it props up and the index generality weighed. These results had served of base for ranking of existence or inexistence the Universities, how much of the information of services in its web sites. In analysis inferencial the result of the test of correlation or association of the independent variaveis (level, concept of the CAPES and period of existence of the program) with the caracteristicas, called was gotten categories of services. For this analysis the estatisticos methods had been used: coefficient of Spearman and the Test of Fisher. But the category you discipline of the Program of Mestrado presented significance with variavel independent and concept of the CAPES. Main conclusion of this study it was ausencia of satandardization o how much to the subjective aspects, design, hierarchy of information navigability and content precision and the accessibility inexistence and convergence. How much to the quantitative aspects, the information services offered by web sites of the evaluated Universities, still they do not present a satisfactory and including quality. Absence of strategies, adoption of tools web, techniques of institucional marketing and services that become them more interactive, navigable is perceived and with aggregate value

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This paper analyzes the development of Bobbin Lace and Design workshops, in the neighborhood of Vila de Ponta Negra (in Natal - RN, Brazil), which proposed contents and practices for its learning and teaching that would compose a possible model for a hybrid Workshop of Bobbin Lace and Lace Design. This research was based on Ergonomic Work Analysis, a methodology used by Ergonomics to analyze work in a wide approach, considering cognitive, social, organizational, as well as other aspects which are relevant to the study of the working situation, in terms of learning/teaching, as addressed on this paper. Some steps of the above mentioned methodology were followed in order to understand the activity of Bobbin Lace craftswomen, by means of bibliographical research centered on this activity. The instruments used for collecting data comprise of conversational actions, analysis of collective work, and spontaneous as well as provoked verbalizations. The adaptations performed in the process of learning/teaching Bobbin Lace for the achievement of Bobbin Lace and Design workshops became instrumental for the continuity of that tradition, attracting new apprentices to this art/craft causing to revitalize a network of handicraft economical activities linked to the Bobbin Lace production, such as the making of cushion, bobbins and trestles

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This study aims to identify, through the application of webometric indicators, which Post-Graduate Courses in Engineering recommended by the Coordination of Improvement of Higher Personnel Education (CAPES) in Brazil stand out in the web space, in relation to the communication process and dissemination of scientific information in the academic environment. For this, we analyzed the structures content of the sites, the use, through the conduct of investigations and searches, the quality of information available, as well as the structure of existent hypertexts in the sites of this universe of search. The tools and methodologies adopted for this study are: search engines (Google, Yahoo), Mapper software (Xenu Link Sleuth) and analysis software and visualization of networks (and Ucinet6 NetDraw). Webometric indicators are also used, such as size of the web sites, visibility, web impact factor, brightness and density of the network. These instruments provide a brief analysis and evaluation for this webometric study. Therefore, from the incursion of the literature used, it appears that there are many advantages of using this type of metric study in the so called Information Society. The obtained results could identify which postgraduate courses in engineering has a better availability of their information on the Web, as well to define which of these courses stands out in relation to the use of their information, which has been outstanding in respect to its impact factor and which offers a greater number of links that serve as a source of information for its users, contributing, in its turn, with the navigability of the same network. In summary, it is asserted that the webometric study presents promising results, which are able to achieve the proposed objectives, as well as identify the factors that contribute significantly to the good visualization of these sites in the network, thus helping the spread of information and scientific communication through the use of the Web.

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This paper aims to conduct a study to evaluate and measure the possible impact that the unavailability of spare parts can have on customer satisfaction for car dealerships in the post-sales. A theoretical-conceptual review on the subject of satisfaction and loyalty, on the backdrop of the reality of the automobile market, allowed the construction of a research tool dedicated to collect opinions of car owners, to allow an analysis empirical relationship between the availability of parts, repairs or scheduled service possible, and change or stay on the mark on the occasion of change of vehicle. 236 forms were applied to car owners in the city of Natal / RN. The results obtained in this survey allowed the identification of the unavailability of parts as a significant factor, among others, the motivation for the customer to switch brands. Collaterally, we could also conclude that the dynamics of change in marks, whatever its motivation, is reflected in the perceived positions of the different brands as the market share both in strictly quantitative terms and in terms of relative positioning, with significant changes in the ranking of consumer preferences for different brands available

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This Master of Science Thesis deals with applying DEA (Data Envelopment Analysis) to the academic performance evaluation of graduate programs in Brazil, exploring it on a Mechanical and Production Engineering Program 2001-2003 data. The data used is that of the national assessment carried by CAPES, the governmental body in charge for graduate program assessment and certification. It is used the CCR output oriented DEA model, the CCR-Output with Assurance Region, and Window Analysis. The main findings are first that the CCR has the concerning problem of zero values of weights of outputs that is not appropriate in a sense that a graduate program has the higher efficiency score zeroing some output (e.g., number of academic papers published). Secondly, the Assurance Region method proved useful. Third, the Window Analysis also gave some light to the consistency of the performance in the time frame analysed. Also, the analysis results in the understanding that the Mechanics and Production Engineering should not be assessed jointly like currently applied by CAPES and rather should be assessed in its own field separately. Finally, the result of the DEA analysis showed some serious inconsistencies with the CAPES method. Graduate programs considered excellent has got low performance score and vice versa. This Thesis provides a strong argument in order to use DEA at least as a complimentary methodology for graduate program performance evaluation in Brazil

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This paper presents a new multi-model technique of dentification in ANFIS for nonlinear systems. In this technique, the structure used is of the fuzzy Takagi-Sugeno of which the consequences are local linear models that represent the system of different points of operation and the precursors are membership functions whose adjustments are realized by the learning phase of the neuro-fuzzy ANFIS technique. The models that represent the system at different points of the operation can be found with linearization techniques like, for example, the Least Squares method that is robust against sounds and of simple application. The fuzzy system is responsible for informing the proportion of each model that should be utilized, using the membership functions. The membership functions can be adjusted by ANFIS with the use of neural network algorithms, like the back propagation error type, in such a way that the models found for each area are correctly interpolated and define an action of each model for possible entries into the system. In multi-models, the definition of action of models is known as metrics and, since this paper is based on ANFIS, it shall be denominated in ANFIS metrics. This way, ANFIS metrics is utilized to interpolate various models, composing a system to be identified. Differing from the traditional ANFIS, the created technique necessarily represents the system in various well defined regions by unaltered models whose pondered activation as per the membership functions. The selection of regions for the application of the Least Squares method is realized manually from the graphic analysis of the system behavior or from the physical characteristics of the plant. This selection serves as a base to initiate the linear model defining technique and generating the initial configuration of the membership functions. The experiments are conducted in a teaching tank, with multiple sections, designed and created to show the characteristics of the technique. The results from this tank illustrate the performance reached by the technique in task of identifying, utilizing configurations of ANFIS, comparing the developed technique with various models of simple metrics and comparing with the NNARX technique, also adapted to identification

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This work proposes hardware architecture, VHDL described, developed to embedded Artificial Neural Network (ANN), Multilayer Perceptron (MLP). The present work idealizes that, in this architecture, ANN applications could easily embed several different topologies of MLP network industrial field. The MLP topology in which the architecture can be configured is defined by a simple and specifically data input (instructions) that determines the layers and Perceptron quantity of the network. In order to set several MLP topologies, many components (datapath) and a controller were developed to execute these instructions. Thus, an user defines a group of previously known instructions which determine ANN characteristics. The system will guarantee the MLP execution through the neural processors (Perceptrons), the components of datapath and the controller that were developed. In other way, the biases and the weights must be static, the ANN that will be embedded must had been trained previously, in off-line way. The knowledge of system internal characteristics and the VHDL language by the user are not needed. The reconfigurable FPGA device was used to implement, simulate and test all the system, allowing application in several real daily problems

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The nanometric powders have special features that usually result in new properties, originating applications or expanding them in various fields of knowledge. Because having a high area/volume ratio, phenomena such as superficial strength of adsorption becomes greater than the weight of the powder which makes more difficult its handling. The high power of agglomeration of these powders requires study and development of equipments to enable its management into the plasma torch. The objective of this work is to develop a powder feeder which can solve the mainly problems about insertion of powder into the thermal spray developed in the laboratory of plasmas, which are carried out with plasma torch arc not transferred (plasma spray). Therefore, it was made a aluminum s powder feeder and tests were performed to verify their operation and determine its rate of deposition by spraying powders of niobium pentoxide (Nb2O5) and titanium dioxide (TiO2) with particle sizes less than 250 mesh (<0.063 mm). We used masses of 0.5 g - 1.0 g and 1.5 g of each powder in tests lasting 15 seconds - 20 to 25 seconds for each mass. The tests were performed in two ways: at atmospheric pressure using argon gas with a flow of 9 l / min as carrier gas and through a Venturi pipe also using argon gas with a flow of 9 l / min as carrier gas and with a flow of 20 l/min as the feed gas passing through the Venturi pipe. The powder feeder developed in this paper is very easy to be handling and building, resulting in feeding rate of 0.25 cm3/min - 1.37 cm3/min. The TiO2 showed higher feeding rates than the Nb2O5 in all tests, and the best rates were obtained with tests using mass 1.5 g and time of 15 seconds, reaching feeding rate of 1.37 cm3/min. The flow of feed had low interference in feeding rate during the tests

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The aluminothermic reduction consists in an exothermic reaction between a metallic oxide and aluminum to produce the metal and the scum. The extracted melted metal of that reaction usually comes mixed with particles of Al2O3 resulting of the reduction, needing of subsequent refine to eliminate the residual impure as well as to eliminate porosities. Seeking to obtain a product in powder form with nanometric size or even submicrometric, the conventional heat source of the reaction aluminothermic , where a resistor is used (ignitor) as ignition source was substituted, for the plasma, that acts more efficient way in each particle of the sample. In that work it was used as metallic oxide the niobium pentoxide (Nb2O5) for the exothermal reaction Nb2O5 + Al. Amounts stoichiometric, substoichiometric and superestoichiometric of aluminum were used. The Nb2O5 powder was mixed with aluminum powder and milled in planetarium of high energy for a period of 6 hours. Those powders were immerged in plasm that acts in a punctual way in each particle, transfering heat, so that the reaction can be initiate and spread integrally for the whole volume of the particle. The mixture of Nb2O5 + Al was characterized through the particle size analysis by laser and X-ray diffraction (DRX) and the obtained product of reaction was characterized using the electronic microscopy of sweeping (MEV) and the formed phases were analyzed by DRX. Niobium powders with inferior sizes to 1 mm were obtained by that method. It is noticed, through the analysis of the obtained results, that is possible to accomplish the aluminothermic reduction process by plasma ignition with final particles with inferior sizes to the original oxide

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The lanthanum strontium cobalt iron oxide (La1-xSrxCo1-yFeyO3 LSCF) is the most commonly used material for application as cathode in Solid Oxide Fuel Cells (SOFCs), mainly due to their high mixed ionic electronic conductivity between 600 and 800ºC. In this study, LSCF powders with different compositions were synthesized via a combination between citrate and hydrothermal methods. As-prepared powders were calcined from 700 to 900°C and then characterized by X-ray fluorescence, X-ray diffraction, thermal analyses, particle size analyses, nitrogen adsorption (BET) and scanning electronic microscopy. Films of composition La0,6Sr0,4Co0,2Fe0,8O3 (LSCF6428), powders calcined at 900°C, were screen-printed on gadolinium doped ceria (CGO) substrates and sintered between 1150 and 1200°C. The effects of level of sintering on the microstructure and electrochemical performance of electrodes were evaluated by scanning electronic microscopy and impedance spectroscopy. Area specific resistance (ASR) exhibited strong relation with the microstructure of the electrodes. The best electrochemical performance (0.18 ohm.cm2 at 800°C) was obtained for the cathode sintered at 1200°C for 2 h. The electrochemical activity can be further improved through surface activation by impregnation with PrOx, in this case the electrode area specific resistance decreases to values as low as 0.12 ohm.cm2 (800°C), 0.17 ohm.cm2 (750°C) and 0.31 ohm.cm2 (700°C). The results indicate that the citrate-hydrothermal method is suitable for the attainment of LSCF particulates with potential application as cathode component in intermediate temperature solid oxide fuel cells (IT-SOFCs)

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Plasma DC hollow cathode has been used for film deposition by sputtering with release of neutral atoms from the cathode. The DC Plasma Ar-H2 hollow cathode currently used in the industry has proven to be effective in cleaning surfaces and thin film deposition when compared to argon plasma. When we wish to avoid the effects of ion bombardment on the substrate discharge, it uses the post-discharge region. Were generated by discharge plasma of argon and hydrogen hollow cathode deposition of thin films of titanium on glass substrate. The optical emission spectroscopy was used for the post-discharge diagnosis. The films formed were analyzed by mechanical profilometry technique. It was observed that in the spectrum of the excitation lines of argon occurred species. There are variations in the rate of deposition of titanium on the glass substrate for different process parameters such as deposition time, distance and discharge working gases. It was noted an increase in intensity of the lines of argon compared with the lines of titanium. Deposition with argon and hydrogen in glass sample observed a higher rate deposition of titanium as more closer the sample was in the discharge

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Many applications require that the plasma discharge is produced apart from the surface to be processed, thus preventing damage caused by bombardment and/or plasma radiation. In the post-discharge regime in various applications thermally sensitive materials can be used. In this work, active species produced by discharge and post-discharge hollow cathode were diagnosed by optical emission spectroscopy and mass spectrometry. The discharge was produced with the gases Ar and Ar - N2 gas flow ranging from 1 to 6 cm3/min and electric current between 150 to 600 mA. It was estimated that the ion density inside the hollow cathode, with 2 mm diameter ranged between 7.71 and 14.1 x 1015 cm-3. It was observed that the gas flow and the electric current changes the emission intensity of Ar and N2 species. The major ionic species detected by quadrupole mass spectrometry were Ar+ and N2+. The ratio of optical emission intensities of N2(1 +)/Ar(811 nm) was related to the partial pressure of N2 after the hollow cathode discharge at low pressure

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The crude glycerine is a raw material that can be used in a wide variety of products. Even with all the impurities inherent in the process of being obtained, the crude glycerin is already in a marketable product. However, the market is much more favorable to the commercialization of purified glycerine. The glycerin is a byproduct gotten from the process of transesterification of waste oils and fats in the production of biodiesel. More recently, the deployment of the new Federal Law of Brazil, related to the implementation of energy resources, forces, from 2008, the increase of 2% biodiesel in diesel common with prospects for 5% (B5). Therefore, it is indispensable that new routes of purification as well as new markets are developed. The objective of this work was to purify, through ion exchange, the crude glycerin, obtained from the reaction of transesterification of cottonseed oil. The cottonseed oil was characterized as the fatty acid composition and physical-chemical properties. The process of ion exchange was conducted in batch. In this process were used strong cation, low anion resins and a mixed resin used to de-ionize water. The purified glycerin was characterized as the content of metals. Tests were performed with activated charcoal adsorption, and for this, it was made tests of time contact with coal as well as quantity of coal used. The time of activation, the amount of the activation solution, the contact time of the glycerol solution in resins, the amount and type of resin applied were evaluated. Considering the analysis made with activated charcoal, when the glycerin solution was treated using the resins individually it was observed that in the conditions for treatment with 10 g of resin, 5 hours of contact with each resin and 50 mL of glycerin solution, its conductivity decreased to a cationic resin, increased to the anionic resin and had a variable value with respect to resin mixed. In the treatment in series, there was a constant decrease in the conductivity of the solution of glycerin. Considering two types of treatment, in series and individually, the content of glycerol in glycerin pre-purified solution with the different resins varied from 12,46 to 29.51% (diluted solution). In analysis performed without the use of activated charcoal, the behavior of the conductivity of the solution of glycerin were similar to results for treatment with activated charcoal, both in series as individually. The solution of glycerin pre-purified had a glycerol content varying from 8.3 to 25.7% (diluted solution). In relation to pH, it had a behavior in accordance with the expected: acid for the glycerin solution treated with cationic resin, basic when the glycerin solution was treated with the anionic resin and neutral when treated with the mixed resin, independent of the kind of procedure used (with or without coal, resins individually or in series). In relation to the color of the glycerin pre-purified solution, the resin that showed the best result was the anionic (colorless), however this does not mean that the solution is more in pure glycerol. The chromatographic analysis of the solutions obtained after the passage through the resins indicated that the treatment was effective by the presence of only one component (glycerol), not considering the solvent of the analysis

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Nowadays, the growing environmental worry leads research the focus the application of alternative materials from renewable resources on the industrial process. The most common vegetable oil extractant using around the world is the hexane, a petroleum derived, toxic and flammable. Based on this fact, the goal of this work was to test vegetable oil extractions from sunflower seeds cultivated on the Rio Grande do Norte State using two extraction process, the mechanical expelling and solvent extraction, this one using hexane and ethanol as a alternative solvent. The solvent extractions were carried out in the Soxhlet extractor in three different extraction times (4, 6, and 8 hours). The effect of solvent and extraction time was evaluated. The mechanical extraction was carried out in a expeller and the sunflower oil obtained was characterized by its physical-chemical properties and compared with sunflower refinery oil. Furthermore this work also explored the pyrolysis reaction carried out by thermogravimetry measurement as alternative route to obtain biofuel. For this purpose the oil samples were heated to ambient temperature until 900°C in heating rate of 5, 10, 20ºC min-1 with the objective evaluated the kinetics parameters such activation energy and isoconversion. The TG/DTG curves show the thermal profile decomposition of triglycerides. The curves also showed that antioxidant presents on the refinery oil not influence on the thermal stability of sunflower oil. The total yield of the extraction s process with hexane and ethanol solvent were compared, and the results indicated that the extraction with ethanol were more efficient. The pyrolysis reaction results indicated that the use of unpurified oil required less energy to obtain the bio-oil

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The objective of this study was to evaluate the displacement of petroleum/diesel solutions, at different concentrations, observing the effect of ultrasonic vibrations in fluids present in porous media to obtain an increase in oil production. The bubbles produced by ultrasound implode asymmetrically in the rock, generating liquid jets with high speed, displacing the oil present in porous media. The oil/diesel solutions were prepared with concentrations ranging from 20 g/L to 720 g/L in oil in relation to diesel and its viscosities were obtained in a Brookfield Rheometer RS2000, with temperature ranging from 25 to 55 °C. After, calculations were performed to obtain the activation energy data for oil/diesel solutions. For oil recovery experiments, cylindrical samples of porous rock (core samples), with resin around the perimeter and its two circular bases free to allow the passage of fluids, were first saturated with 2% KCl solution and after with oil solutions. The results of oil extraction were satisfactory for all studied solutions, being obtained up to 68% partial displacement with saline solution injection. The ultrasound system was used after saline injection, increasing oil displacement, with oil extractions ranging from 63% to 79%. During the experiments, it was observed the warming of core samples, helping to reduce the viscosity of more concentrated systems, and consequently enhancing the percentage of advanced recovery for all studied solutions