A new microcontrolled structural health monitoring system based on the electromechanical impedance principle

This article presents a new method to detect damage in structures based on the electromechanical impedance principle. The system follows the variations in the output voltage of piezoelectric transducers and does not compute the impedance itself. The proposed system is portable, autonomous, versatile, and could efficiently replace commercial instruments in different structural health monitoring applications. The identification of damage is performed by simply comparing the variations of root mean square voltage from response signals of piezoelectric transducers, such as lead zirconate titanate patches bonded to the structure, obtained for different frequencies of the excitation signal. The proposed system is not limited by the sampling rate of analog-to-digital converters, dispenses Fourier transform algorithms, and does not require a computer for processing, operating autonomously. A low-cost prototype based on microcontroller and digital synthesizer was built, and experiments were carried out on an aluminum structure and excellent results have been obtained. © The Author(s) 2012.

EMG activity of trunk stabilizer muscles during Centering Principle of Pilates Method

This study aimed to analyze the electromyographic (EMG) activity of iliocostalis lumborum (IL), internal oblique (IO) and multifidus (MU) and the antagonist cocontraction (IO/MU and IO/IL) during the performance of Centering Principle of Pilates Method. Participating in this study were eighteen young and physically fit volunteers, without experience in Pilates Method, divided in two groups: low back pain group (LBPG, n = 8) and control group (CG, n = 10). Two isometric contractions of IO muscles (Centering Principle) were performed in upright sitting posture. EMG signal amplitude was calculated by Root Mean Square (RMS), which was normalized by RMS maximum value. The common area method to calculate the antagonist cocontraction index was used. MU and IO activation and IO/MU cocontraction (. p < 0.05) were higher in CG. The CG therefore showed a higher stabilizer muscles recruitment than LBPG during the performance of Centering Principle of Pilates Method. © 2012 Elsevier Ltd.

Histopathology of the tegument of rabbits infested by Rhipicephalus sanguineus (ACARI: IXODIDAE) ticks and exposed to selamectin (active principle of acaricide Revolution®, Pfizer)

Ticks are hematophagous ectoparasites which can transmit several diseases to the host during their feeding process. When ticks mechanically damage the tissue, they eventually induce inflammatory responses on the skin spot where they are fixed. One of the alternatives to control these ectoparasites is the use of chemical substances like selamectin - the active principle of Pfizer's antiparasitic Revolution® - a macrocyclic lactone capable of doing neurotoxic damage to the tick and eventually eliminating infestation in dogs and cats. The purpose of this study was to analyze, using histological and histochemical techniques, the occurrence of morphophysiological alterations in the skin of the host rabbits exposed to selamectin and infested with Rhipicephalus sanguineus (Acari: Ixodidae). Histologically, the exposed and infested rabbits showed a partial and/or total decrease in the stratum corneum and the epithelium decreased in the number of cell layers, consequently reducing the stratification (thinning) and quite pronounced formations of sub-epidermal edemas with consequent disorganization of collagen fibers in the dermal layer's connective tissue. Histochemical tests showed strong periodic acid-Schiff-positive reaction in the hair follicle and some regions of the dermis, besides resynthesis of collagen fibers detected by Mallory's trichrome technique. The obtained results showed that selamectin acts like a toxicant agent when in contact with the skin of the rabbit infested with ticks, inducing morphophysiological alterations in the acute inflammatory process in the animal's tegument. Selamectin is a chemical substance which has a dose-dependent action since higher concentrations cause greater morphophysiological damage in the skin of rabbits. © 2013 Springer-Verlag Berlin Heidelberg.

Damage Detection Based on Electromechanical Impedance Principle and Principal Components

This paper presents a novel time domain approach for Structural Health Monitoring (SHM) systems based on Electromechanical Impedance (EMI) principle and Principal Component Coefficients (PCC), also known as loadings. Differently of typical applications of EMI applied to SHM, which are based on computing the Frequency Response Function (FRF), in this work the procedure is based on the EMI principle but all analysis is conducted directly in time-domain. For this, the PCC are computed from the time response of PZT (Lead Zirconate Titanate) transducers bonded to the monitored structure, which act as actuator and sensor at the same time. The procedure is carried out exciting the PZT transducers using a wide band chirp signal and getting their time responses. The PCC are obtained in both healthy and damaged conditions and used to compute statistics indexes. Tests were carried out on an aircraft aluminum plate and the results have demonstrated the effectiveness of the proposed method making it an excellent approach for SHM applications. Finally, the results using EMI signals in both frequency and time responses are obtained and compared. © The Society for Experimental Mechanics 2014.

Interdito e silêncio: análise de alguns enunciados

Within the field of Discourse Analysis (Pêcheux) and psychoanalysis, this work states interdiction and silence as constituents and founders of the discourse. In short, we claim that what makes it possible to say anything is that it is not possible to say it all, so something must remain unsaid. The logic principle here is that the contradiction, the excluded founds the possible. For such task we use the logic square. We also propose and build a square of the saying or of the utterances. The analysis made here points toward the existence of the impossible in language, and also indicates how important a modal approach of language can be.

Morphological alterations of epidermis of rabbits infested by R. sanguineus ticks and exposed to Selamectin (active principle of Pfizer Revolution (R) acaricide): A confocal microscopy study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The Occurrence of Autophagic Cell Death in the Tegument of Rabbits Pre-Infested with Rhipicephalus sanguineus and Exposed to Selamectin (Active Principle of Acaricide Pfizer Revolution (R))

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of Avocado/Soybean Unsaponifiables on Osseointegration: A Proof-of-Principle Preclinical In Vivo Study

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

Goppa codes through polynomials of B[X;(1/2^2)Z_0] and its decoding principle

In this paper, we present a decoding principle for Goppa codes constructed by generalized polynomials, which is based on modified Berlekamp-Massey algorithm. This algorithm corrects all errors up to the Hamming weight $t\leq 2r$, i.e., whose minimum Hamming distance is $2^{2}r+1$.

Fiscal policy contradiction: a perspective on Brazil and Mexico

The aim of this paper is to discuss the quality of fiscal policy in Brazil and Mexico and investigate whether fiscal policy influence is favorable to reduce the unemployment rate. Public spending, which has a positive effect on the level of employment when results in additional aggregate demand, may cause a negative effect on employment, if its financing depends on persistent high interest rates. Brazil and Mexico have engaged in a long effort to control public spending and to reduce the public deficit to zero. Does this policy bring a positive result to the economic activity no matter how actual public deficit has been financed? We select variables related to public budget as public sector borrowing requirements, taxes, public debt and others to form a data base. The fiscal institutional arrangement and the data allow us to evaluate the fiscal policy as a who leand to discuss the importance of credibility and reputation of the government.