RCAAP Repository

The main task in this work is the development of a computational tool that will allow researchers and professionals in the field of solar energy a fast verification of the behavior of solar cells based in the materials used for their assembling, and also to check their operation from different operating scenarios. This model is developed from physical properties of component materials. The change of materials of solar cells, and also the working parameters are quickly simulated by the program allowing a comparison among different technologies allowing a broad vision of their behavior. The program ellaborated from mathematical model present in the literature, allows a quick visualization of simulation of answers of photovoltaic cells behavior, as well as the behavior of the whole solar panel built under specified electrical configurations. Therefore, the researcher will save time, materials, and financial resources, among other savings, since the results are quickly obtained with a high degree of fidelity to the real behavior of the solar panels present today in the market.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Studies concerning the analysis of march correlated to paralympic sport athletics are scarce. The purpose of this study was to determine, quantify and compare the kinematic changes in linear and angular parameters of human gait between groups with cerebral palsy, classified according to criteria the International Paralympic Committee in classes: T35 diplegic, T36 athetoid and ataxic and T37 hemiplegic. Measures of anthropometric variables, linear and angular kinematics were performed. For gait assessment was used movement system capture Optitrack and Motion Capture ARENATM Software. For statistical analysis, we performed an analysis of variance with post hoc Tukey test. The results showed significant differences ( p < 0,05) between groups for some linear variables such as Right Step Length, step width, Left Simple Support, Right Simple Support, Paralyzed Balance Left and Paralyzed Balance Right and some angular variables flexion-extension during initial support as: Left Hip Flexion and Paralyzed Left Hip Flexion, during the mid-stance: Right dorsiflexion and Paralyzed Right dorsiflexion and some angular variables of slope during the initial support: Left Leaning on the Trunk and Paralyzed Left Leaning on the Trunk during the final support Leaning right Hip, Left Leaning Trunk and Paralyzed Left Leaning Trunk and the average balance Right Leaning Trunk and Paralyzed Right Leaning Trunk. These results corroborate the differentiation made within the functional classification based on qualitative criteria by the International Paralympic Committee (IPC) between the three classes (T35, T36 and T37). There was a finding of \"subgroups\", in other words, people with different degrees of affections that belong to the same functional class according to the traditional classification of IPC. Depending on the degree of variability of occurrence within the same class, power would bring together those people in subclasses with similar abilities and therefore, contribute to a large number of Paralympic athletes achieve better results since these groups would be competing in more homogeneous.

The study of cortical processes is important to comprehend the neurological deficits and thus, allow the development of strategies to help on the treatment of such deficits. The mechanisms of integration and coordination of the activities of cortical regions may be studied with the analysis of phase synchronization between signals obtained from multiple cortical areas. Phase synchronization is a method for measuring the functional connectivity, which is, the temporal correlation for cortical areas, however is not capable of identifying the causal relations among the areas, defined as effective connectivity. In the national scenario, it still doesn t exist a profound knowledge on the techniques used to evaluate the functional cortical synchronization patterns, especially the ones based on surface electroencephalography. This work propose the development of a platform to evaluate the functional connectivity pattern, based on phase synchronization, for electroencephalographic signals. The tool was developed in MATLAB® and quantifies the phase synchronization index of electroencephalographic signals by means of the Hilbert Transform. The system was tested and its performance validated by means of synthetic sine waves and real EEG data. The results of the tests using synthetic data showed that the algorithm performs correctly, generating the expected values for signals highly synchronized and non-synchronized. A case study was performed, in which electroencephalographic data were collected from a volunteer during read-aloud tasks. The results showed significant synchronization between cortical regions responsible for reading and the production of speech. This tool has the potential to be used in applications in which it is desired to map the functional connectivity between cortical areas, such as, brain machine interfaces, neurofeedback and rehabilitation of neurological dysfunctions.

This paper proposes two new topological arrangements consisting in connecting the AC power supply in series with two DC converters, one operating during the positive half-cycle and the other during the negative half cycle. It is noteworthy that these DC converters in series in a case are Buck EIE converters and on the other a buck. The results obtained with both arrangements are analyzed and compared. The control strategy is developed with the goal of imposing an AC voltage output within the limits imposed by the rules in order to mitigate the problems associated with Sags and Swells from the AC power supply . The principles of operation as well as the experimental and simulation results obtained in both steady and transient state are presented and validated for a 1kVA experimental prototype. Finally, some works still on progress related to this dissertation are presented, like the multilevel compensation and the three phase compensation.

The objective of this research is a preliminary assessment, through load flow studies, the performance of low voltage distribution network in a specific region of the city of Palmas, Tocantins, when connecting Distributed Generation (DG) sources, more specifically, grid-connected photovoltaic systems. Accordingly, with the help of PSAT program, a toolbox of MatLab, it was developed a model of this distribution network so as to reflect the real situation of the residential area of 1106 South Block, city of Palmas TO, taking into account the information and data provided by local power utility and manufacturers. Thus, a model was specified for a grid-connected photovoltaic system, capable of generating only active power, obeying the radiation and temperature profile of the city for a specific day chosen for the study, ie, one with the greatest consumption recorded by the local power utility in year 2012. Tests conducted with the developed model were used to evaluate the behavior of active and reactive power flows without/ with DG in the low voltage network, voltage variations and power factors of the network that are connected grid-connected photovoltaic system. This research has observed that the solar photovoltaic generation offering several advantages both for the concessionaires as well as for consumers where they are installed, as being clean, renewable and with less environmental impact. However, it is important to mention that, despite presenting advantages, only after ANEEL (the National Electrical Energy Agency) published the Normative Nº 482, it started incentives to explore such alternative source.

It is highlighted the influence and use of Computer Graphics discipline, applied in different areas of health. Positive results have been reported by several studies mainly pointing reliability, which enables creation of new techniques in search of better results. The available literature for orthognathic surgery demonstrates the severe shortage of technologies in supporting surgeons and their patients. The number of patients using traditional braces and do not get satisfactory results is significantly large, leaving only the option of undergoing orthognathic surgery, which might involve the breaking of bones and soft tissue and muscles arrangements. Such procedure is indicated for patients who have very pronounced symptoms like problems in the relationship between the teeth, muscles and bones, face s muscles pain, tongue position and temporomandibular joint (TMJ). These problems may cause headaches and stomach disorders, besides respiration and phonation issues and apnea. This study describes the analysis and three-dimensional simulation in repositioning of the upper and lower jaws concerning soft tissue and skin, with the goal of assisting in a better surgical planning using CT scans efficiently, thus supporting doctor and patient in the submission of the surgical procedure. There is also the intention to include the software prototype created as part of this study in the InVesalius (TM) software adding support for orthognatic surgery procedure. A group of surgeons evaluated the software prototype presented in this study. The potential of this tool is discussed in this dissertation and its test results.

The development of an electric power theory under nonsinusoidal conditions is a wide and complex topic. The first researches in the area date back from 1927 and 1932 and, up to now, there is no consensus. The main issue is to understand how the power flows in an electric circuit works since classic definitions of electric power, presented in engineering textbooks, do not reliably depict the energy flow\'s interactions in systems with distorted voltage and current waveforms. In this context, the qualification and quantification of reactive power is the most controversial. Thus, this dissertation aims to contribute to studies in non-sinusoidal systems with focus on power definitions with a special attention to reactive power and its implications. Some comments on the active power are also made.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The aim of this masterthesis is to study and develop a methodology for the first stage of the deployment of a Small Hydraulic Plant (SHP), the Estimate Hydroelectric Potential, stage in which is studied the favorable and unfavorable situations to the deployment of small plants. Basing on environmental, technical and economic criteria of a watershed, according secondary data that are provided by agencies and institutions responsible for each criterion. Data collections for the study observe the geological and geotechnical, environmental, infrastructure and logistics, water availability and topography aspects. Moreover, it presents the use of GIS (Geographic Information Systems) to generate maps where relevant aspects are presented and analyzed, and it use the Hydrology Statistics for the hydrological study, to verify the flow of a river or precipitation at a local or region. At the end, it presents the estimate average energy generated, or average power, basing first on the variation of flow over an average year, and constant height, then with constant values of flow and height, estimating the specific power location, the type of water turbine, power and voltage of electric generator. It was applied a study case of the methodology in the watershed of the Tijuco river, limited to the city of Ituiutaba MG.

The use of simulation in industrial environments allows the user to perform tests and define applied control strategies to cases where the network configuration, tuning the loop of control and the study of the timing constraints on the control can be evaluated before the implementation in the real plant. In this context there is the need to be developed simulated industrial networks, systems modeling interfaces protocols and possible integration with physical sensors available. This work presents a tool for real time simulation of an industrial process and data exchange with a server via Modbus protocol. That data can be viewed and manipulated by a supervisory system.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

This work presents a proposal based on controlled switching capacitors at the time of direct start of induction motors when they are energy supplied by synchronous generators isolated. This procedure enables mitigate or even eliminate the sag that occurs during this transitional period. Allowing a smoother start condition of the engine, when viewed by the synchronous generator. To validate the proposal, will be issued the results obtained through computer simulations, with the achieved in practical experiments. After these analyzes, it will be shown that the proposal can be applied for generator sets, that when supplying motor loads have their design made based on starting such machines. May lead to one on generator set sizing, cause various problems for its operation.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais