Energy harvesting performance of piezoelectric electrospun polymer fibers and polymer/ceramic composites

The energy harvesting efficiency of electrospun poly(vinylidene fluoride), its copolymer vinylidene fluoride-trifluoroethylene and composites of the later with piezoelectric BaTiO������on interdigitated electrodes has been investigated. Further, a study of the influence of the electrospinning processing parameters on the size and distribution of the composites fibers has been performed. It is found that the best energy harvesting performance is obtained for the pure poly(vinylidene fluoride) fibers, with power outputs up to 0.03 ���W and 25 ���W under low and high mechanical deformation. The copolymer and the composites show reduced power output due to increased mechanical stiffness. The obtained values, among the largest found in the literature, the easy processing and the low cost and robustness of the polymer, demonstrate the applicability of the developed system.

Public hearings as a tool to improve participation in regulatory policies: case study of the National Agency of Electric Energy

The participation of citizens in public policies is an opportunity not only to educate them, but also to increase their empowerment. However, the best way for deploying participatory policies, defining their scope and approach, still remains an open and continuous debate. Using as a case study the Brazilian National Agency of Electric Energy (Aneel), with its public hearings about tariff review, this paper aims at analyzing the democratic aspects of these hearings and challenges the hypothesis of many scholars about the social participation bias in this kind of procedure. This study points out a majority participation of experts, contrasting with the political content of discussions. And, this way, it contributes to a critical analysis of the public hearings as a participatory tool, indicating their strengths and their aspects which deserve a special attention.

Modeling the Diffusion of Energy Performance Contracting

The Portuguese Energy Policy considers the development of a commercially viable and competitive market for energy performance contracting (EPC) as a main mechanism to achieve the objectives of energy efficiency improvement. This paper proposes a study to investigate how to achieve widespread adoption of energy performance contracting by means of system dynamics modelling and simulation. To explore and gather insights on this question, a system dynamics model representing the system of the Portuguese EPC market at industry level will be created. The simulation of that model will provide a helpful basis for analysing and explaining the development of key variables, and accelerating learning on the managerial, organizational and political adaptation processes that foster the diffusion of EPC adoption. The first phase of this research project aims at identifying and analysing the key factors and critical cause-effect relations that drive the adoption of EPC. With this purpose, a qualitative content analysis on relevant documents was performed and a set of interviews was conducted. That data was analysed to capture the critical variables and its interrelation to formulate a preliminary representation of the system structure as stock and flow diagrams.

Imunidade relativa �� poliomielite em crian��as de zero a dez anos, ap��s o "Quarto Dia Nacional de Vacina����o Contra a Poliomielite" com a vacina����o oral trivalente, tipo Sabin, em ��rea da Regi��o da Grande S��o Paulo, SP (Brasil), 1982

Efetuou-se um levantamento soro-epidemiol��gico, abrangendo 898 crian��as, para a verifica����o da imunidade aos poliov��rus 1, 2 e 3 por meio da determina����o dos t��tulos de anticorpos neutralizantes. De 522 crian��as, ou seja, de 58,1% da popula����o estudada, foi poss��vel a obten����o de informa����es referentes �� situa����o vacinal a partir de anota����es existentes nas pr��prias Cadernetas de Vacina����o. Neste ��ltimo sub-grupo foi estudado o estado imunit��rio em rela����o ao n��mero de doses de vacina oral tipo Sabin recebidas. Os resultados mostraram alta propor����o de imunes para os tr��s tipos de poliov��rus entre as crian��as estudadas, por��m tamb��m revelaram a exist��ncia de lacuna imunit��ria nos menores de um ano, especialmente no primeiro semestre de vida. N��o foram observadas diferen��as importantes na propor����o de imunes segundo o sorotipo considerado. Salientou-se a necessidade de um alerta constante e permanente em rela����o �� ocorr��ncia de poss��veis surtos epid��micos em segmentos mais vulner��veis da popula����o, particularmente entre crian��as menores de 1 ano.

Direct Power Control of Matrix Converter Based Unified Power Flow Controllers

This paper presents the Direct Power Control of Three-Phase Matrix Converters (DPC-MC) operating as Unified Power Flow Controllers (UPFC). Since matrix converters allow direct AC/AC power conversion without intermediate energy storage link, the resulting UPFC has reduced volume and cost, together with higher reliability. Theoretical principles of DPC-MC method are established based on an UPFC model, together with a new direct power control approach based on sliding mode control techniques. As a result, active and reactive power can be directly controlled by selection of an appropriate switching state of matrix converter. This new direct power control approach associated to matrix converters technology guarantees decoupled active and reactive power control, zero error tracking, fast response times and timely control actions. Simulation results show good performance of the proposed system.

Predictive Optimal Matrix Converter Control for a Dynamic Voltage Restorer with Flywheel Energy Storage

This paper presents a predictive optimal matrix converter controller for a flywheel energy storage system used as Dynamic Voltage Restorer (DVR). The flywheel energy storage device is based on a steel seamless tube mounted as a vertical axis flywheel to store kinetic energy. The motor/generator is a Permanent Magnet Synchronous Machine driven by the AC-AC Matrix Converter. The matrix control method uses a discrete-time model of the converter system to predict the expected values of the input and output currents for all the 27 possible vectors generated by the matrix converter. An optimal controller minimizes control errors using a weighted cost functional. The flywheel and control process was tested as a DVR to mitigate voltage sags and swells. Simulation results show that the DVR is able to compensate the critical load voltage without delays, voltage undershoots or overshoots, overcoming the input/output coupling of matrix converters.

Development of a penetration test for timber impregnation products for use in old buildings

This paper studies the application of commercial biocides to old maritime pine timber structures (Pinus pinaster Ait.) that have previously been impregnated with other products. A method was developed in the laboratory to be used in situ to determine the impregnation depth achieved by a new generation biocide product applied to timber from an old building. This timber had once been treated with an unknown product difficult to characterize without extensive analysis. The test was initially developed in laboratory conditions and later tested on elements of the roof structure of an 18th century building. In both cases the results were promising and mutually consistent with penetration depths for some treatments reaching 2.0 cm. The application in situ proved the tests viability and simplicity of execution giving a clear indication on the feasibility of possible re-treatments.

Diagn��stico nutricional de crian��as de zero a cinco anos atendidas pela rede municipal de sa��de em ��rea urbana da regi��o sul do Brasil, 1988

Como um dos requisitos para a operacionaliza����o do Sistema de Vigil��ncia Alimentar e Nutricional (SISVAN) no munic��pio de Curitiba, PR, Brasil, foi realizado um levantamento epidemiol��gico retrospectivo com dados de 1988, que buscou atrav��s do exame antropom��trico conhecer a preval��ncia e as formas de desnutri����o cal��rico-prot��ico de crian��as menores de cinco anos atendidas pela Rede Municipal de Sa��de de Curitiba. Numa amostra de 4.213 crian��as encontrou-se pela Classifica����o de G��mez 28,1% de desnutridos, sendo que 3,6% destes situam-se no grau II e III. A Classifica����o de Seoane e Latham modificada por Batista Filho revelou que 19,7% das crian��as apresentam alguma forma de desnutri����o. O perfil antropom��trico revelou maior concentra����o de crian��as no primeiro decil a partir do sexto m��s de vida, sendo esta mais acentuada no grupo et��rio de 12 a 24 meses para os ��ndices: peso/idade e altura/idade.

Scaling of the elastic contribution to the surface free energy of a nematic liquid crystal on a sawtoothed substrate

We characterize the elastic contribution to the surface free energy of a nematic liquid crystal in the presence of a sawtooth substrate. Our findings are based on numerical minimization of the Landau-de Gennes model and analytical calculations on the Frank-Oseen theory. The nucleation of disclination lines (characterized by non-half-integer winding numbers) in the wedges and apexes of the substrate induces a leading order proportional to q ln q to the elastic contribution to the surface free-energy density, with q being the wave number associated with the substrate periodicity.

Power converter topologies for wind energy conversion systems: Integrated modeling, control strategy and performance simulation

This paper presents new integrated model for variable-speed wind energy conversion systems, considering a more accurate dynamic of the wind turbine, rotor, generator, power converter and filter. Pulse width modulation by space vector modulation associated with sliding mode is used for controlling the power converters. Also, power factor control is introduced at the output of the power converters. Comprehensive performance simulation studies are carried out with matrix, two-level and multilevel power converter topologies in order to adequately assert the system performance. Conclusions are duly drawn.

Projecto Ano Zero : desenvolvimento de compet��ncias t��cnico-art��sticas em jovens adultos atrav��s da T��cnica de Dan��a Cl��ssica, com vista ao ingresso no curso de Licenciatura da Escola Superior de Dan��a

Relat��rio Final de Projecto Pedag��gico apresentado �� Escola Superior de Dan��a com vista �� obten����o do Grau de Mestre em Metodologias do Ensino da Dan��a.