Sistema de emulação de aerogeradores para aplicação em geração distribuída de energia elétrica

Power generation from alternative sources is at present the subject of numerous research and development in science and industry. Wind energy stands out in this scenario as one of the most prominent alternative in the generation of electricity, by its numerous advantages. In research works, computer reproduction and experimental behavior of a wind turbine are very suitable tools for the development and study of new technologies and the use of wind potential of a given region. These tools generally are desired to include simulation of mechanical and electrical parameters that directly affect the energy conversion. This work presents the energy conversion process in wind systems for power generation, in order to develop a tool for wind turbine emulation testing experimental, using LabVIEW® software. The purpose of this tool is to emulate the torque developed in an axis wind turbine. The physical setup consists of a three phase induction motor and a permanent magnet synchronous generator, which are evaluated under different wind speed conditions. This tool has the objective to be flexible to other laboratory arrangements, and can be used in other wind power generation structures in real time. A modeling of the wind power system is presented, from the turbine to the electrical generator. A simulation tool is developed using Matlab/Simulink® with the purpose to pre-validate the experiment setup. Finally, the design is implemented in a laboratory setup.

Potencial antioxidante de extratos hidroalcoólicos de mirtilo, polpa de açaí e goji berry: efeito na estabilidade oxidativa e sensorial em queijo petit suisse

The consumer interest in healthy foods with high amounts of antioxidants is one of the important factors for reducing the risk of disease and it has encouraged researchers and industry to develop innovative and functional products and ingredients. To that end, the objective of this research was to study the bioactive compounds present in the acai pulp, blueberry and goji berry samples, as well as the phenolic compounds form of extraction using the response surface methodology (RSM), antioxidant and antimicrobial activity of it, identification and quantification of compounds by high-performance liquid chromatography (HPLC) and, at the end, the development of petit suisse cheeses added with freeze-dried extracts of the samples. A 2³ factorial design was used to analyze the solvent effect (ethanol and water), time (30 and 60 min) and temperature (30 °C and 60 °C) on the extraction and determination of total phenolic compounds (TPC) and antioxidant activity (AA). The variables time and temperature had a positive effect on the antioxidant activity (AA) in their highest levels with 60 min and 60 °C respectively. The ethanol solvent 80 % is more efficient in TPC extraction with AA in all arrays. The identification of phenolic compounds performed by HPLC revealed the presence of catechin, epicatechin, rutin, myricetin, chlorogenic acid, coumaric acid and ferulic acid. Regarding the AA the acai pulp showed higher activity in vitro when extracted by 60 °C for 60 min, but none of the three extracts analyzed under these conditions showed antibacterial activity against Staphylococcus aureus and Salmonella bongori in the concentrations tested (95.00 to 2.34 mg/mL. For petit suisse cheeses added with phenolic extract of the samples, the sample containing goji berry achieved greater sensory acceptance among judges (75.67%), second only to the commercial sample used for comparison with 91.56 % of acceptance. In relation to the storage time, the oxidation was evaluated by the level of thiobarbituric acid reactive substances and color analysis. Both analysis were satisfactory, making the extracts addition an alternative to preserve the product properties and give it a high content of bioactive and nutritive compounds.

Proposta de uma matriz de decisão em energia hidrelétrica com o uso do método multicritério, para formulação de políticas públicas no estado do Paraná

Brazil is internationally acknowledged for its renewable sources, most notably, hydroelectric power plant projects which correspond to 65% of electricity production supply to the National Interconnected System. The main question behind this research is: what are the weights and the relative importance of the variables which have influence on the decision making process for the expansion of hydroelectric generation projects in Parana? The main objective is to propose a multi-criteria decision procedure, in association with water sources options that take into consideration the weight and relative importance of the alternatives having influence on the decision by enterprises in the generation of electricity in the state of Paraná. As far as the approach to the problem is concerned, this research can be classified as having mixed methodologies, applying Content Analysis, Delphi technique and the Analytic Hierarchy Process. Following Delphi methodology, a group of 21 was selected for data collection, all of those linked to Paranaense hydroelectricity market. And the main result was the construction of a decision tree in which it was possible to identify the importance and relative weight of the elements associated with the four dimensions of energy. In environmental dimension, the highest relative weight was placed on the loading capacity of Parana system; the economic dimension, the amortization of investment; in social dimension, the generation of direct work places and in institutional dimension, the availability of suitable sources of financing. Policy makers and business managers make their decisions based on specific criteria related to the organization segment, market information, economic and political behavior among other indicators that guide them in dealing with the typical tradeoffs of projects in hydropower area. The results obtained in the decision tree show that the economic bias is still the main factor in making investment decisions. However, environmental impacts on the State loading capacity, income generation, providing opportunities for direct as well as indirect jobs. And at an institutional level, the absence of funding sources show that the perception of experts is focused on other issues beyond the logic behind development per se. The order of priority of variables in this study indicates that in the current environment of uncertainty in the Brazilian economy as many variables must be analyzed and compared in order to optimize the scarce resources available to expand local development in relation to Paranaense water matrix.