Efeitos da estimulação ambiental sobre os aspectos motores, cognitivos e neuronais em um modelo farmacológico progressivo da doença de Parkinson

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Proteção em sistemas elétricos com geração distribuída utilizando a transformada wavelet

A typical electrical power system is characterized by centr alization of power gene- ration. However, with the restructuring of the electric sys tem, this topology is changing with the insertion of generators in parallel with the distri bution system (distributed gene- ration) that provides several benefits to be located near to e nergy consumers. Therefore, the integration of distributed generators, especially fro m renewable sources in the Brazi- lian system has been common every year. However, this new sys tem topology may result in new challenges in the field of the power system control, ope ration, and protection. One of the main problems related to the distributed generati on is the islanding formation, witch can result in safety risk to the people and to the power g rid. Among the several islanding protection techniques, passive techniques have low implementation cost and simplicity, requiring only voltage and current measuremen ts to detect system problems. This paper proposes a protection system based on the wavelet transform with overcur- rent and under/overvoltage functions as well as infomation of fault-induced transients in order to provide a fast detection and identification of fault s in the system. The propo- sed protection scheme was evaluated through simulation and experimental studies, with performance similar to the overcurrent and under/overvolt age conventional methods, but with the additional detection of the exact moment of the fault.

Topologia de gerador de distúrbios elétricos baseada em conversores de potência

Electrical disturbances such as voltage sags, interruptions and voltage unbalances might cause serious problems for the end-user and for the companies of generation and transmission of energy. Few years ago, those companies have been using methods and equipments of protection to avoid the disturbances’ presence or to mitigate their effects on the power system. Disturbances generators are used to analyse the behavior of electrical and electronic equipments affected by disturbances. The analysis of those failures allows the development of appropriated protection equipments. In this paper, the development of a disturbances generator based on power converters is presented. The disturbance generator developed is able to generate some symmetrical disturbances, such as: voltage sags, voltage swells and harmonic distortion. The control strategy used in the disturbance generator is based on discrete and repetitive control. The steps of the design of the control and of the filter used for reducing harmonic in the output, are detailed in the text. Are presented the obtained results on computational simulations and the obtained results on laboratory tests.

Análise de agrupamentos dos dados de DFA oriundos de perfis elétricos de indução de poços de petróleo

The main objective of this study is to apply recently developed methods of physical-statistic to time series analysis, particularly in electrical induction s profiles of oil wells data, to study the petrophysical similarity of those wells in a spatial distribution. For this, we used the DFA method in order to know if we can or not use this technique to characterize spatially the fields. After obtain the DFA values for all wells, we applied clustering analysis. To do these tests we used the non-hierarchical method called K-means. Usually based on the Euclidean distance, the K-means consists in dividing the elements of a data matrix N in k groups, so that the similarities among elements belonging to different groups are the smallest possible. In order to test if a dataset generated by the K-means method or randomly generated datasets form spatial patterns, we created the parameter Ω (index of neighborhood). High values of Ω reveals more aggregated data and low values of Ω show scattered data or data without spatial correlation. Thus we concluded that data from the DFA of 54 wells are grouped and can be used to characterize spatial fields. Applying contour level technique we confirm the results obtained by the K-means, confirming that DFA is effective to perform spatial analysis

Links hipertextuais na comunicação científica: análise webométrica dos sítios acadêmicos latino-americanos em ciências sociais

VANTI, Nadia. Links hipertextuais na comunicação científica: análise webométrica dos sítios acadêmicos latino-americanos em Ciências Sociais. Porto Alegre, 2007. 292 f. Tese (Doutorado em Comunicação e Informação) – Universidade Federal do Rio Grande do Sul. Porto Alegre, 2007.

Um espaço pioneiro de modernidade educacional: Grupo Escolar Augusto Severo -Natal/RN -1908-13

Cette recherche a pour but d analyser l Ecole Augusto Severo, située dans la ville de Natal dont la construction date de 1907,étant le premier établissement d enseignement primaire à l état du Rio Grande do Norte, pendant le processus de restructuration de l enseignement républicain. On cherche à comprendre la représentation de ce milieu scolaire, comme équipement urbain, dans le processus de modernisation de la ville et comme modèle éducationnel pour l état entre 1908 et 1913. En se servant des études historiographes sur le processus de modernisation de quelques villes brésiliennes et des innovations de l enseignement public primaire au pays, à la fin du dix-neuvième siècle et pendant la première décennie du vingtième siècle, comme source pour mieux saisir le contexte général et spécifique. On reconstitue les aspects économiques, sociaux et politiques déterminants des interventions publiques réalisées dans cette ville par les gouvernements républicains ayant comme obectif la construction d une ville embellie,hygiénique et civilisée. Située au quartier Ribeira, principal scénario de la modernité de Natal, l Ecole Augusto Severo est mise em relief comme symbole de civilité du paysage urbain de l époque pour le citoyen du Rio Grande do Norte. Elle disposait de services d énergie et d un tram électrique. Il y avait devant, un grand lac arborisé et une station ferroviaire. A côté, il y avait le théâtre Carlos Gomes (actuellement Alberto Maranhão). Par suíte de son imposante architecture, raffiné style éclectique,on reflète l idéal républicain des elites locales, avec une conception d espace symbolique et éducative de surveillance et contrôle, caractéristiques de l école graduée républicaine

Estudo da síntese e sinterização de pós compósitos do sistema Ta-Cu

Ta-Cu bulk composites combine high mechanical resistance of the Ta with high electrical and thermal conductivity of the Cu. These are important characteristics to electrical contacts, microwave absorber and heat skinks. However, the low wettability of Ta under Cu liquid and insolubility mutual these elements come hard sintering this composite. High-energy milling (HEM) produces composite powders with high homogeneity and refines the grain size. This work focus to study Ta-20wt%Cu composite powders prepared by mechanical mixture and HEM with two different conditions of milling in a planetary ball mill and then their sintering using hydrogen plasma furnace and a resistive vacuum furnace. After milling, the powders were pressed in a steel dye at a pressure of 200 MPa. The cylindrical samples pressed were sintered by resistive vacuum furnace at 10-4torr with a sintering temperature at 1100ºC / 60 minutes and with heat rate at 10ºC/min and were sintered by plasma furnace with sintering temperatures at 550, 660 and 800ºC without isotherm under hydrogen atmosphere with heat rate at 80ºC/min. The characterizations of the powders produced were analyzed by scanning electron microscopy (SEM), x-ray diffraction (XRD) and laser granulometry. After the sintering the samples were analyzed by SEM, XRD and density and mass loss tests. The results had shown that to high intense milling condition produced composite particles with shorter milling time and amorphization of both phases after 50 hours of milling. The composite particles can produce denser structure than mixed powders, if heated above the Cu melting point. After the Cu to arrive in the melting point, liquid copper leaves the composite particles and fills the pores

Estudo da moagem de alta energia e sinterização de pós compósitos W-Cu

The Tungsten/copper composites are commonly used for electrical and thermal objectives like heat sinks and lectrical conductors, propitiating an excellent thermal and electrical conductivity. These properties are dependents of the composition, crystallite size and production process. The high energy milling of the powder of W-Cu produces an dispersion high and homogenization levels with crystallite size of W very small in the ductile Cu phase. This work discusses the effect of the HEM in preparation of the W-25Cu composite powders. Three techniques of powder preparation were utilized: milling the dry with powder of thick Cu, milling the dry with powder of fine Cu and milling the wet with powder of thick Cu. The form, size and composition of the particles of the powders milled were observed by scanning electron microscopy (SEM). The X-ray diffraction (XRD) was used to analyse the phases, lattice parameters, size and microstrain of the crystallite. The analyse of the crystalline structure of the W-25Cu powders milled made by Rietveld Method suggests the partial solid solubility of the constituent elements of the Cu in lattice of the W. This analyse shows too that the HEM produces the reduction high on the crystallite size and the increase in the lattice strain of both phases, this is more intense in the phase W

Desenvolvimento de um sistema de nitretação por plasma em fonte pulsada e sua influencia sobre a nitretação do titânio

The pulsed plasma nitriding is a solution currently used in the metallurgical industry to resolve problems earlier in the processing of parts by using plasma DC voltage. These problems consisted mainly of edge effect and opening arches caused due to non-uniformity of electric fields on uneven surfaces. By varying the pulse width can reduce these effects. However, variations in pulse width can drastically affect the population of the plasma species and hence the final microstructure of the nitrided layer. In literature, little is known about the effect of process parameters on the properties of the plasma species and, consequently, the surface properties. We have developed a system of nitriding with pulsed source with fixed period of 800  pulse width is variable. Examined the variation of these parameters on the properties of nitrided surface when keeping constant temperature, gas composition, flow, pressure and power. It was found that the values of width and pulse repetition time of considerable influence in the intensities of the species present in plasma. Moreover, we observed the existence of the edge effect for some values of pulse widths, as well as changes in surface roughness and hardness

Caracterização de compósitos Nb-20%cu obtidos por moagem de alta energia e sinterizados por fase líquida

In this work, was studied the formation of a composite of the refractory metal niobium with copper, through the process of high-energy milling and liquid phase sintering. The HEM can be used to synthesize composite powders with high homogeneity and fine size particle distribution. It may also produce the solid solubility in immiscible systems such as Nb-Cu, or extend the solubility of systems with limited solubility. Therefore, in the immiscible system Cu-Nb, the high-energy milling was successfully used to obtain the composite powder particles. Initially, the formation of composite particles during the HEM and the effect of preparation technique on the microstructure of the material was evaluated. Four loads of Nb and Cu powders containing 20%wt Cu were synthesized by MAE in a planetary type ball mill under different periods of grinding. The influence of grinding time on the metal particles is evaluated during the process by the withdrawal of samples at intermediate times of milling. After compaction under different forces, the samples were sintered in a vacuum furnace. The liquid phase sintering of these samples prepared by HEM produced a homogeneous and fine grained. The composite particles forming the sintered samples are the addition of a hard phase (Nb) with a high melting point, and a ductile phase (Cu) with low melting point and high thermal and electrical conductivities. Based on these properties, the Nb-Cu system is a potential material for many applications, such as electrical contacts, welding electrodes, coils for generating high magnetic fields, heat sinks and microwave absorbers, which are coupled to electronic devices. The characterization techniques used in this study, were laser granulometry, used to evaluate the homogeneity and particle size, and the X-ray diffraction, in the phase identification and to analyze the crystalline structure of the powders during milling. The morphology and dispersion of the phases in the composite powder particles, as well the microstructures of the sintered samples, were observed by scanning electron microscopy (SEM). Subsequently, the sintered samples are evaluated for density and densification. And finally, they were characterized by techniques of measuring the electrical conductivity and microhardness, whose properties are analyzed as a function of the parameters for obtaining the composite

Formulação de massas cerâmicas para porcelanas elétricas utilizando resíduos oriundos de corpos de fusíveis

The power industry generates as waste ceramic bodies of electrical fuses that are discarded after use. The formulation of ceramic bodies for porcelain electrical insulators using waste from the bodies fuse allocation promotes environmentally appropriate, through the reuse of the material. This work evaluated the technical feasibility of using waste for use in electrical porcelains with formulations containing the residue, feldspar and kaolinite. The raw materials were processed through grinding and sieving to 200 mesh. The ceramic material obtained from the proposed formulations with 25%, 30%, 34% and 40% of the residue went through a vibratory mill for grinding and homogenization, and then were sieved at 325 mesh. The samples were shaped in a uniaxial press, with the application of 25 MPa and sintered at 1100° C, 1150°C, 1200°C, 1225°C and 1250°C, at levels of 20 and 45 minutes. Were also developed bodies of evidence with reference formulations obtained without residue, to establish a comparison on physical, mechanical and electrical. The tests were conducted and technology: linear shrinkage, porosity, water absorption, resistance to bending to three points, measuring insulation resistance electrical resistivity of the material, X-ray diffraction and X-ray fluorescence Waste characterizations pointed to the existence of two phases: mullite and quartz phases are of great importance in the microstructure of the ceramic and this fact reveals a possibility for reuse in electrical porcelains. The mullite is an important constituent because it is a phase that makes it possible to increase the mechanical strength in addition to the body allows the use at high temperatures. The use of ceramic bodies residue fuses, proved feasible for application in electrical porcelain and the most significant results were obtained by the formulations with 25% waste and sintering at 1200°C

Síntese e caracterização do líquido iônico tetrafluoroborato de 1-metil-3-(2,6-(S)-dimetiloct-2-eno)-imidazol como eletrólito para produção de hidrogênio via eletrólise da água

Ionic liquids (ILs) are organic compounds liquid at room temperature, good electrical conductors, with the potential to form as a means for electrolyte on electrolysis of water, in which the electrodes would not be subjected to such extreme conditions demanding chemistry [1]. This paper describes the synthesis, characterization and study of the feasibility of ionic liquid ionic liquid 1-methyl-3(2,6-(S)-dimethyloct-2-ene)-imidazole tetrafluoroborate (MDI-BF4) as electrolyte to produce hydrogen through electrolysis of water. The MDI-BF4 synthesized was characterized by thermal methods of analysis (Thermogravimetric Analysis - TG and Differential Scanning Calorimetry - DSC), mid-infrared spectroscopy with Fourier transform by method of attenuated total reflectance (FTIR-ATR), nuclear magnetic resonance spectroscopy of hydrogen (NMR 1H) and cyclic voltammetry (CV). Where thermal methods were used to calculate the yield of the synthesis of MDI-BF4 which was 88.84%, characterized infrared spectroscopy functional groups of the compound and the binding B-F 1053 cm-1; the NMR 1H analyzed and compared with literature data defines the structure of MDI-BF4 and the current density achieved by MDI-BF4 in the voltammogram shows that the LI can conduct electrical current indicating that the MDI-BF4 is a good electrolyte, and that their behavior does not change with the increasing concentration of water

Desenvolvimento de uma unidade pirolítica com reator de cilindro rotativo: obtenção de bio-óleo

The demand for alternative sources of energy drives the technological development so that many fuels and energy conversion processes before judged as inadequate or even non-viable, are now competing fuels and so-called traditional processes. Thus, biomass plays an important role and is considered one of the sources of renewable energy most important of our planet. Biomass accounts for 29.2% of all renewable energy sources. The share of biomass energy from Brazil in the OIE is 13.6%, well above the world average of participation. Various types of pyrolysis processes have been studied in recent years, highlighting the process of fast pyrolysis of biomass to obtain bio-oil. The continuous fast pyrolysis, the most investigated and improved are the fluidized bed and ablative, but is being studied and developed other types in order to obtain Bio-oil a better quality, higher productivity, lower energy consumption, increased stability and process reliability and lower production cost. The stability of the product bio-oil is fundamental to designing consumer devices such as burners, engines and turbines. This study was motivated to produce Bio-oil, through the conversion of plant biomass or the use of its industrial and agricultural waste, presenting an alternative proposal for thermochemical pyrolysis process, taking advantage of particle dynamics in the rotating bed that favors the right gas-solid contact and heat transfer and mass. The pyrolyser designed to operate in a continuous process, a feeder containing two stages, a divisive system of biomass integrated with a tab of coal fines and a system of condensing steam pyrolytic. The prototype has been tested with sawdust, using a complete experimental design on two levels to investigate the sensitivity of factors: the process temperature, gas flow drag and spin speed compared to the mass yield of bio-oil. The best result was obtained in the condition of 570 oC, 25 Hz and 200 cm3/min, temperature being the parameter of greatest significance. The mass balance of the elementary stages presented in the order of 20% and 37% liquid pyrolytic carbon. We determined the properties of liquid and solid products of pyrolysis as density, viscosity, pH, PCI, and the composition characterized by chemical analysis, revealing the composition and properties of a Bio-oil.

Avaliação do desempenho funcional de crianças com paralisia cerebral de acordo com níveis de comprometimento motor

Contextualization: Several studies have examined the mobility of this group of children, however little is known about the impact of motor function in activities of daily living, considering the seriousness of their neuromotor damage. Objective: Identify the functional differences of children with Cerebral Palsy with different levels of motor dysfunction and correlate these differences with the areas of mobility, self-care and social function in functional ability and caregiver´s assistance of these children. Methods: An l analytical cross-section search was developed, which were part 70 children / families aged from 4 to 7.5 years, in the Rehabilitation Center for Children. As tools were used the Pediatric Evaluation Disability Inventory (PEDI) and the Gross Motor Function Classification System (GMFCS). Data analysis was performed by ANOVA and Pearson's correlation tests. Results: The results show the functional variability of children CP in different severity levels of motor disfunction This variation was observed in the areas of mobility, self-care and social function. The results also showed a strong correlation between the domains mobility and self-care, mobility and social function. Conclusions: The variability shown by the children with CP, suggests the use of PEDI and GMFCS as this association appears to increase the understanding of how the gross motor functions are related to activities of daily living, describing the best commitments and their degree of impact on functional activities. This correlation demonstrates how mobility is crucial to evaluate the performance and guide the therapeutic practice, to develop the children´s potencial, and guide the caregiver in stimulation

Correr, saltar, lançar, dialogar :uma reflexão sobre corpo e aprendizagem nas aulas de educação física

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