Comportamento mecânica da mola T de Beta-titânio: influência da marca comercial e do alivio de tensão estrutural

Pós-graduação em Ciências Odontológicas - FOAR

Modelamento e correção de descentralização das imagens de tempo de trânsito

As imagens da parede do poço obtidas através da ferramenta UBI (Ultrasonic Borehole Imager) são amplamente utilizadas por geólogos e engenheiros de petróleo para identificar eventos geológicos nas paredes de poços abertos e na inspeção dos tubos de revestimento, uma vez que este perfil praticamente fornece uma fotografia da parede do poço. As ferramentas de imageamento acústico produzem imagens do tempo de trânsito e da amplitude do pulso acústico gerado pela ferramenta e refletido na parede do poço. Entretanto, estas imagens podem ter uma interpretação não realista, uma vez que elas podem ter seu aspecto alterado em razão do movimento da ferramenta no interior do poço. Este trabalho apresenta o modelamento das imagens de tempo de trânsito a partir da aplicação do critério de Coulomb para a ruptura da parede do poço submetida a um estado plano de tensões, a qual fornecerá a seção do poço, que é a forma geométrica que será traçada pela ferramenta de imageamento acústico do poço. O deslocamento ascensional da ferramenta e as imperfeições da parede do poço, normalmente, são os responsáveis pelo deslocamento da posição do transdutor em relação ao eixo do poço. Este efeito pode ter grande responsabilidade nas imperfeições das imagens de tempo de trânsito. Assim, a correção dessas imagens, chamada de correção da descentralização, busca o reposicionamento do transdutor para a posição do eixo do poço. Apresenta-se, também, um método de correção do efeito da descentralização da ferramenta baseado neste modelamento. O método é proposto com base na geometria analítica plana e no método do raio para a definição do tempo de trânsito do pulso acústico, com o objetivo de reconstruir as imagens de tempo de trânsito obtidas com a ferramenta descentralizada, ou seja, corrigir estas imagens tornando-as como se fossem obtidas com a ferramenta centralizada em relação ao eixo do poço.

Desenvolvimento de sistema para verificação metrológica de transformadores de corrente IN SITU em sistemas de alta tensão utilizando transdutor óptico

Este trabalho apresenta o desenvolvimento e a aplicação em campo de um sistema para verificação metrológica de transformadores de corrente em alta tensão. O sistema foi desenvolvido utilizando como premissas básicas a portabilidade e a confiabilidade metrológica, de tal forma que pudesse ser facilmente transportado e instalado, sem interrupção do fornecimento de energia elétrica nem o uso de infraestrutura complexa de transporte e montagem. O sistema utiliza como padrão de referência um transdutor ótico, cujo sensor mede a corrente elétrica do primário do transformador de corrente a ser verificado através do efeito magneto-ótico de Faraday. Ele também é composto por outros instrumentos padrão que medem a corrente elétrica do secundário do transformador de corrente sob verificação, e realizam a comparação entre esta e o sinal da saída do transdutor ótico padrão. Foram realizados ensaios em laboratório e em campo. Os ensaios em campo foram realizados em duas subestações em Belém/PA, visando avaliar a correta operação do sistema em condições de alta tensão e alta corrente. Os ensaios foram realizados em seis transformadores de corrente conectados em 230 kV, em condições médias de carga, e obtiveram resultados satisfatórios.

Desenvolvimento de dispositivos para diagnósticos e genotipagem de Hepatite C

Pós-graduação em Química - IQ

Triplex Doppler da artéria renal e a relação entre a ecobiometria dos rins com distância atlanto-coccígea e altura em Canis familiaris

O objetivo do trabalho foi estabelecer a relação entre a ecobiometria renal com medidas de conformação corporal como a distância atlanto-coccígea (DAC) e a altura (H) de cães adultos saudáveis, obtendo-se parâmetros de normalidade para avaliar o tamanho e volume renal, bem como estabelecer valores de referência para avaliar a perfusão sanguínea dos rins por meio do índice de resistividade (IR) e do índice de pulsatilidade (IP) do ramo principal da artéria renal. No estudo foram utilizados 22 cães adultos sem raça definida, sendo 11 machos e 11 fêmeas. Os animais foram previamente aferidos quanto a DAC e a H. Os exames ultra-sonográficos foram realizados com um aparelho HDI 4000 PHILIPS munido de um transdutor microconvexo multifreqüêncial (5-8 MHz), dispositivos Doppler Colorido e Doppler de Fluxo. Os animais foram posicionados em decúbito lateral direito ou esquerdo, de acordo com o rim a ser avaliado. Os diâmetros longitudinal (DL) e dorsoventral (DDV) dos rins foram mensurados na secção longitudinal e, o diâmetro transversal (DT) foi aferido no plano transversal. O volume (V) foi calculado automaticamente pelo software do ultra-som. Com o uso do Triplex Doppler, o IR e o IP das artérias renais direita e esquerda foram obtidos. Todos os dados foram apresentados em média ± EPM. Análises de regressão linear foram realizadas tendo o DL, DDV, DT e V como variáveis dependentes e a DAC e H como variáveis independentes. Os IR e IP dos rins direito e esquerdo foram comparados pelo teste t de Student. A DAC variou de 54-78cm para machos e 37-71cm para fêmeas e a altura variou entre 34-64 cm para os machos e 24-57cm para as fêmeas. As médias obtidas para DL, DDV, DT e V dos rins esquerdo e direito foram: 5,24±0,27cm, 3,07±0,15cm, 3,07±0,9cm, 28,01±3,4mL e 4,50±0,19cm, 2,88±0,14cm, 2,71±0,15cm, 21,27±2,6mL, respectivamente. As análises de regressão linear entre as medidas lineares e volume renal com a DAC e a H foram significativas para os interceptos e coeficientes de regressão (P<0,01). Houve diferenças estatísticas quando comparado os IR e IP entre os rins direito e esquerdo (P=0,001), sendo que as médias para IR e IP dos rins esquerdo e direito foram 0,62±0,08; 1,34±0,18 e 0,70±0,06; 1,62±0,13; respectivamente. Os dados obtidos no presente trabalho podem auxiliar na avaliação do tamanho, volume e perfusão dos rins de cães adultos.

Ultra-sonografia na avaliação andrológica de bovinos da raça Nelore

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação ultrassonográfica do bulbo ocular em cães submetidos à facoemulsificação com ou sem implante de lente intraocular

This study aimed to describe and compare the ultrasonographic alterations in dogs' eyes submitted to facectomy with or without intraocular lens implant (IOL), to assist in the diagnosis of possible alterations related to the surgical procedure and IOL implantation. Nineteen dogs with cataract (21 eyes) were submitted to phacoemulsification and late postoperative evaluation (at five years). The animals were initially submitted to complete ophthalmological exams which preceded the sonogram. Dogs were divided in three groups: (CA) aphakic dogs (n= 11); (PP) pseudophakic dogs with implantation of two IOLs in piggyback (n=5) and (PL) pseudophakic dogs with implantation of a veterinary IOL (n = 5). The ultrasound was carried under the administration of a topic local anesthetic, with a multi frequency linear transducer of 10 MHz. Biometric eye measurements were also performed. The clinical alterations observed were IOL dislocation, retinal detachment, asteroid hyalosis, and vitreous degeneration. Ultrasound examination was an excellent diagnostic tool, as it was possible to confirm and classify these changes. The piggyback implant reduced the measurements between the ciliary body and the vitreous chamber obtained from the ocular biometry when compared to other usual procedures, with no difference between the axial length and the anterior chamber.

Comparing label free electrochemical impedimetric and capacitive biosensing architectures

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

Measurement of Radiant Energy using Pyroelectric Polymer/Ceramic Composite

Monitoring non-ionizing radiant energy is increasingly demanded for many applications such as automobile, biomedical and security system. Thermal type infrared (IR) sensors can operate at room temperature and pyroelectric materials have high sensitivity and accuracy for that application. Working as thermal transducer pyroelectric sensor converts the non-quantified thermal flux into the output measurable quantity of electrical charge, voltage or current. In the present study the composite made of poly(vinylidene fluoride) -PVDF and lead zirconate titanate (PZT) partially recovered with polyaniline (PAni) conductor polymer has been used as sensor element. The pyroelectric coefficient p(T) was obtained by measuring the pyroelectric reversible current, i.e., measuring the thermally stimulated depolarization current (TSDC) after removing all irreversible contribution to the current such as injected charge during polarization of the sample. To analyze the sensing property of the pyroelectric material, the sensor is irradiated by a high power light source (halogen lamp of 250 W) that is chopped providing a modulated radiation. A device assembled in the laboratory is used to change the light intensity sensor, an aluminum strip having openings with diameters ranging from 1 to 10 mm incremented by one millimeter. The sensor element is assembled between two electrodes while its frontal surface is painted black ink to maximize the light absorption. The signal from the sensor is measured by a Lock-In amplifier model SR530 -Stanford Research Systems. The behavior of the output voltage for an input power at several frequencies for PZT-PAni/PVDF (30/ 70 vol%) composite follows the inverse power law (1/ f) and the linearity can be observed in the frequency range used.

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.

A new tuning fork with different vibration frequencies as an aid to bronchopulmonary hygiene physiotherapy

Background: The main function of the mucociliary system is the removal of particles or substances that are potentially harmful to the respiratory tract. The tuning fork therapeutic for the purpose of bronchial hygiene has still not been described in the literature. The optimal vibration frequency to mobilize secretions is widely debated and varies between 3 and 25 Hz. It is expected that a tuning fork is able to generate vibrations in the thorax, facilitating bronchial hygiene. The aim of the present study is to develop tuning forks with different frequencies, for use in bronchopulmonary hygiene therapy. Methods: The first tuning fork was made with a fixed frequency of 25 Hz and it was recorded in the Brazilian institution of patent registration. This device generated a frequency of 25 Hz and had a weight of 521 g, with dimensions of 600 mm in total length. The device is characterized by a bottom end containing a transducer with a diameter of 62 mm and a thickness of 5/16 mm (8''), a rod removable 148 mm, fork length of 362 mm and an extension at the upper end of sinuous shape bilaterally.The tuning forks must be applied at an angle of 90° directly on the chest wall of the patient after pulmonary auscultation for location of secretions. The tuning fork is activated by squeezing the tips of the extensions together and releasing them in a sudden movement. Results: This study shows the result of the development of others three tuning forks of different dimensions to generate different frequencies. Each equipment reaches a fixed frequency preset of 12, 15 and 20 Hz measured by digital oscilloscope. Conclusions: The tuning fork models developed in this study generated different frequencies proposed by the scientific literature as effective in the mobilization of pulmonary secretions.

Impedance-derived electrochemical capacitance spectroscopy for the evaluation of lectin-glycoprotein binding affinity

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

Efeito agudo de diferentes intensidades de exercícios com pesos sobre o volume e a contração voluntária máxima isométrica, em idosas treinadas

The prescription of strength training intensity (ST) by maximum repetition (RM) is characterized by a decrease in the number of repetitions in multiple series. Some studies have shown that reductions in the intensity of exercise can optimize the volume of training with similar acute neuromuscular behaviors. The objective of the study was to investigate the acute effect of two different ST intensities on the training volume, maximum voluntary contraction (MVC) and rate of force development (RFD) in elderly women. The study included eight trained women (66.7 ± 6.7 years; 7.6 ± 17.8 kg; 159 cm; 29.33 ± 5.80 kg/m²). They underwent to three experimental conditions: two different intensities of ST (100% and 80% of 15-RM) on a chair for Leg Extension and a control condition. In the condition to 100% of 15 RM, all participants performed three sets to the concentric muscle fatigue, whereas in the condition to 80% involved the use of two sets of 15 repetitions and only the third to the concentric muscle fatigue. The order of experimental conditions was randomized. The MVC and RFD were determined on the basis of the isometric forcetime curve analysis which was obtained by a force transducer fixed on the unit Bonnet Chair, in the pre and after four and ten minutes for each experimental conditions. The total volume was calculated by multiplying the number of repetitions in three sets by the load in kg. Descriptive statistical analysis procedures were employed (mean ± standard deviation) in addition to two-way ANOVA. The level of significance was set at p <0.05. It was neither main effect of moment or condition, nor condition x moment interaction for MVC and RFD. For the total volume, no significant difference was noted between the conditions (100 and 80% of 15-RM). For sustainability of ...(Complete abstract click electronic access below)

Efeito agudo de diferentes volumes de alongamento estático na contração voluntária máxima de idosas

Several studies have shown that different stretching routines can lead to decreases on acute neuromuscular system performance. Although the deficit in muscle strength mediated by different methods of stretching has been systematically observed, few studies have investigated the possible existence of a dose-response relationship between the amount of stretching and muscle strength deficit in older adults. In this context, the objective of this study was to investigate the acute effect of two different stretching volumes on isometric force-time curve (Cf-t) in elderly women. The study included 13 older women (64.08 ± 4.27 years, 69.98 ± 10.56 kg, 157.90 ± 8.66 cm, 28.25 ± 4.22 kg/m²). The participants visited the laboratory for five consecutive days, among which the first two were used for familiarization. During the other three days the participants underwent experimental conditions: control (C) stretch 30 seconds (AE30) and stretch 60 seconds (AE60). For the AE30 and AE60 conditions, three series of passive static stretching were performed, with duration of 30 and 60 seconds, respectively. The experimental conditions were performed with an interval of at least 24 hours between them and the order of execution was randomized. The recording of isometric Cf-t of the knee extensor muscles was performed in extensor chair connected to a force transducer. Measurements were recorded immediately after each experimental condition, for five seconds. For statistical analysis, descriptive procedures were used and ANOVA one way to check possible changes on the Maximal Voluntary Contraction (CVM) and Peak Rate of Force Development (TDFP) among the three conditions (p <0.05). The ANOVA showed no statistically significant difference for CVM and TDFP, between the three conditions. It can be concluded that different volumes of static stretching, three sets ...(Complete abstract click electronic access below)

Colheita de energia usando dispositivos baseados em materiais piezoelétrico

Recently, research on energy harvesting has increased substantially. Many researchers have concentrated their efforts to find the best configuration for these systems and to optimize their output power. In the process of energy harvesting, the electric energy is obtained by converting mechanics energy created by an environment vibration source by a transducer, for example, a thin piezoceramic film. That vibration source is, for example, a beam suffering some mechanic force able to generate a vibration in it, an oscillating beam is the best properly used example. Different mechanisms of electromechanical coupling have been developed to harvesting devices, and a particular interest has been given to the use of models that transform the mechanical vibration into electrical current using a piezoelectric element. In this paper we propose a model to energy harvesting from vibrations, from an oscillating beam, including non-linearities in the piezoelectric coupling and a non-ideal excitation in the material. From this model, it was developed a system to obtain some results about the harvested power by the material. It was demonstrated that the power captured was influenced by the effect of the nonlinearities of the piezoelectric coupling, modifying the system dynamic behavior