Selective current compensators based on the conservative power theory

This paper presents possible selective current compensation strategies based on the Conservative Power Theory (CPT). This recently proposed theory, introduces the concept of complex power conservation under non-sinusoidal conditions. Moreover, the related current decompositions results in several current terms, which are associated with a specific physical phenomena (power absorption P, energy storage Q, voltage and current distortion D). Such current components are used in this work for the definition of different current compensators, which can be selective in terms of minimizing particular disturbing effects. The choice of one or other current component for compensation directly affects the sizing and cost of active and/or passive devices and it will be demonstrated that it can be done to attend predefined limits for harmonic distortion, unbalances and/or power factor. Single-phase compensation strategies will be discussed by means of the CPT and simulation results will demonstrate their performance. © 2009 IEEE.

Influence of voids in the hybrid layer based on self-etching adhesive systems: a 3-D FE analysis

The presence of porosities at the dentin/adhesive interface has been observed with the use of new generation dentin bonding systems. These porosities tend to contradict the concept that etching and hybridization processes occur equally and simultaneously. Therefore, the aim of this study was to evaluate the micromechanical behavior of the hybrid layer (HL) with voids based on a self-etching adhesive system using 3-D finite element (FE) analysis. Three FE models (Mr) were built: Mr, dentin specimen (41x41x82 μm) with a regular and perfect (i.e. pore-free) HL based on a self-etching adhesive system, restored with composite resin; Mp, similar to M, but containing 25% (v/v) voids in the HL; Mpp, similar to Mr, but containing 50% (v/v) voids in the HL. A tensile load (0.03N) was applied on top of the composite resin. The stress field was obtained by using Ansys Workbench 10.0. The nodes of the base of the specimen were constrained in the x, y and z axes. The maximum principal stress (σmax) was obtained for all structures at the dentin/adhesive interface. The Mpp showed the highest peak of σmax in the HL (32.2 MPa), followed by Mp (30 MPa) and Mr (28.4 MPa). The stress concentration in the peritubular dentin was high in all models (120 MPa). All other structures positioned far from voids showed similar increase of stress. Voids incorporated into the HL raised the σmax in this region by 13.5%. This behavior might be responsible for lower bond strengths of self-etching and single-bottle adhesives, as reported in the literature.

Template-based fluoropolymer ferroelectrets with multiple layers of tubular channels

Significant efforts are devoted to developing new ferroelectrets with well-controlled void distributions or uniform voids and with good long-term and thermal stability of the piezoelectricity. Here, we describe the concept, the fabrication, and the most relevant properties of fluoropolymer ferroelectret systems with three separate films of fluoroethylenepropylene (FEP), alternating with two polytetrafluoroethylene (PTFE) templates. The FEP films are selectively fused by means of a lamination process. Two practically identical PTFE templates are used, which have parallel rectangular openings (1.5×30 mm 2) separated by PTFE ridges of 1.5 mm width. After removing the PTFE templates, a three-layer FEP-film sandwich with tubular channels is obtained. We demonstrate that such FEP-film systems exhibit significant and stable piezoelectricity after charging under a high DC voltage. The resulting piezoelectric effect may be further improved by carefully assembling and arranging the PTFE templates during preparation. ©2010 IEEE.

A prospective study on implants installed with flapless-guided surgery using the all-on-four concept in the mandible

Aim: Clinical data are scarce on flapless-guided surgery in the mandible using the all-on-four concept. In addition, limited documentation exists on the latter under immediate loading conditions with a pre-fabricated implant bridge. The aim was to provide detailed documentation focusing on clinical and radiographic outcome and complications. Material and methods: Sixteen systemically healthy non-smoking patients (10 women, 6 men, average age 59 years) with sufficient bone volume in the mandible were operated via flapless-guided surgery using the all-on-four concept. Clinical and radiographic data and complications were registered at 3, 6 and 12 months. Results: The overall implant survival rate was 90% with a trend for higher failure of short implants (P = 0.098). The mean bone level after 12 months of function was 0.83 mm with a maximum of 1.07 mm. Technical complications were common (15/16 patients). These mainly related to a misfit between the pre-fabricated prosthesis and abutment(s) (13/16 patients). Conclusion: If immediate loading of implants is pursued fabrication of the implant bridge should be based on actual impression of the implants at the time of surgery and not on their virtual position. © 2011 John Wiley & Sons A/S.

Termos eponímicos do domínio da dermatologia: conceito, estrutura morfossintática e léxico-semântica e uso em comunicação médica

Pós-graduação em Estudos Linguísticos - IBILCE

Currículos de formação de professores de educação física no estado do Pará: conteúdos curriculares, concepções pedagógicas e modelos de profissionalidade

O estudo se insere no Programa de Pós-Graduação em Educação da Universidade Federal do Pará, na linha de “Currículo e Formação de Professores”, como parte das produções do grupo de pesquisa “Includere”. Tem como objeto de estudo as propostas curriculares adotadas pelos cursos de formação de professores de Educação Física do Estado do Pará, de 2000 a 2010. Possui o seguinte problema: que concepções de Educação Física e modelos de profissionalidade docentes orientam os currículos prescritos adotados pelos cursos de licenciatura em Educação Física do Estado do Pará? Fundamenta-se metodologicamente no materialismo histórico e dialético, na pesquisa do tipo qualitativa e documental. Realiza análise de conteúdo (TRIVIÑOS, 1987; FRANCO, 2008) dos Projetos Políticos Pedagógicos (PPP) de seis cursos de licenciatura em Educação Física do Estado do Pará. Discute questões teóricas e conceituais sobre currículo, seleção curricular, concepções pedagógicas da Educação Física, profissão, profissionalidade e proletarização docente ao longo das seções. Constata que as Diretrizes Curriculares acionais dos Cursos de Graduação em Educação Física (DCNEF) adotam a concepção pedagógica da Aptidão Física e o modelo de profissionalidade técnico-racionalizante. Nos seis currículos de Educação Física investigados, observa que as concepções pedagógicas predominante são a Saúde renovada e a Fenomenológica, com a presença da Desenvolvimentista, Competitivista e Crítico-Superadora, porém, estas se apresentam hibridizadas nos currículos. Identifica que o modelo de profissionalidade docente adotado nos cursos investigados é técnicoracionalizante, apesar do uso de terminologias progressistas e de contradições entre os textos dos PPP e a estrutura curricular. Conclui que os currículos investigados reproduzem as determinações gerais do capital no projeto de formação, porém que é possível resistir às normatizações oficiais, como demonstra o currículo do Curso de Educação Física da Universidade do Estado do Pará, ainda que este se apresente com limitações em relação ao projeto formativo almejado.

Random laser action from flexible biocellulose-based device

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The plant ionome revisited by the nutrient balance concept

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Leakage detection in water pipe networks using electromechanical impedance (EMI) based technique

The electromechanical impedance (EMI) technique has been successfully used in structural health monitoring (SHM) systems on a wide variety of structures. The basic concept of this technique is to monitor the structural integrity by exciting and sensing a piezoelectric transducer, usually a lead zirconate titanate (PZT) wafer bonded to the structure to be monitored and excited in a suitable frequency range. Because of the piezoelectric effect, there is a relationship between the mechanical impedance of the host structure, which is directly related to its integrity, and the electrical impedance of the PZT transducer, obtained by a ratio between the excitation and the sensing signals.This work presents a study on damage (leaks) detection using EMI based method. Tests were carried out in a rig water system built in a Hydraulic Laboratory for different leaks conditions in a metallic pipeline. Also, it was evaluated the influence of the PZT position bonded to the pipeline. The results show that leaks can effectively be detected using common metrics for damage detection such as RMSD and CCDM. Further, it was observed that the position of the PZT bonded to the pipes is an important variable and has to be controlled.

Semi-supervised learning with concept drift using particle dynamics applied to network intrusion detection data

Concept drift, which refers to non stationary learning problems over time, has increasing importance in machine learning and data mining. Many concept drift applications require fast response, which means an algorithm must always be (re)trained with the latest available data. But the process of data labeling is usually expensive and/or time consuming when compared to acquisition of unlabeled data, thus usually only a small fraction of the incoming data may be effectively labeled. Semi-supervised learning methods may help in this scenario, as they use both labeled and unlabeled data in the training process. However, most of them are based on assumptions that the data is static. Therefore, semi-supervised learning with concept drifts is still an open challenging task in machine learning. Recently, a particle competition and cooperation approach has been developed to realize graph-based semi-supervised learning from static data. We have extend that approach to handle data streams and concept drift. The result is a passive algorithm which uses a single classifier approach, naturally adapted to concept changes without any explicit drift detection mechanism. It has built-in mechanisms that provide a natural way of learning from new data, gradually "forgetting" older knowledge as older data items are no longer useful for the classification of newer data items. The proposed algorithm is applied to the KDD Cup 1999 Data of network intrusion, showing its effectiveness.

Estudo sobre os aspectos culturais da terminologia dos contratos de prestação de serviços em língua portuguesa e língua francesa

Pós-graduação em Estudos Linguísticos - IBILCE

Metalinguagem semiótica: empréstimos e redefinições

This paper deals with the issue of terminology and conceptualization in the construction of the semiotic metalanguage. The starting point of this discussion is the scientific thought of C. S. Pierce, R. Bastide and É. Benveniste, who understand that the creation of a new science requires a new and precise terminology. This position is relativized and magnified by the point of view of A. J. Greimas, who defends the centrality of the conceptualization rather than the formalization and the terminological production. Thus, this study proposes and analyses two types of metalinguistic elaboration based on the dialogue with previous theories and disciplines: the borrowing and the redefining.

Esthetic and function improvement by direct composite resins and biomimetic concept

Aim: This case report describe a resin layering restorative technique based on biomimetic concept to improve esthetics in a patient with dental defects that affected both enamel and dentin in anterior teeth. Background: Severe structural defect in anterior teeth compromises esthetics and it is a high challenge to become the defect imperceptible after the restoration. Case description: A clinical sequence of applying different composite resin layers allowed the reproduction of the interaction between hard dental tissues and the restorative material. Conclusion: This technique achieved a satisfactory final esthetic outcome, preserving sound teeth structure and at same time, improved the quality of life of the young patient. Clinical significance: The utilization of the biomimetic concept to increase a disharmonic smile with dental defects is based in a conservative approach, which reached a satisfactory and esthetic outcome.

Multi-task control strategy for grid-tied inverters based on conservative power theory

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

What ethologically based models have taught us about the neural systems underlying fear and anxiety

Classical Pavlovian fear conditioning to painful stimuli has provided the generally accepted view of a core system centered in the central amygdala to organize fear responses. Ethologically based models using other sources of threat likely to be expected in a natural environment, such as predators or aggressive dominant conspecifics, have challenged this concept of a unitary core circuit for fear processing. We discuss here what the ethologically based models have told us about the neural systems organizing fear responses. We explored the concept that parallel paths process different classes of threats, and that these different paths influence distinct regions in the periaqueductal gray - a critical element for the organization of all kinds of fear responses. Despite this parallel processing of different kinds of threats, we have discussed an interesting emerging view that common cortical-hippocampal-amygdalar paths seem to be engaged in fear conditioning to painful stimuli, to predators and, perhaps, to aggressive dominant conspecifics as well. Overall, the aim of this review is to bring into focus a more global and comprehensive view of the systems organizing fear responses.