135 resultados para Ruído (Telecom)


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Nuclear medicine is a medical specialty related to imagery that deals with imaging techniques, diagnosis and therapy, allowing observing the physiological state of tissues noninvasively by marking the molecules participating of these physiological processes with radioactive isotopes, thus creating the called radionuclides. The image of a radionuclide is one of the most important applications of radioactivity in nuclear medicine. The equipment’s of nuclear medicine imaging use the principle of radiation detection, turning it into an electrical signal which, through specific algorithms, allows forming tomographic images that provide information about the functional status of organs. New detection systems have been developed for tomographic acquisitions using solid state detectors. These devices use crystals of cadmium zinc telluride (CdZnTe). Some of the advantages of this detector are a significant improvement of signal to noise ratio, the increased spectral and spatial resolution, which in sum, result in greater clarity of the images obtained, opening new perspectives for imaging protocols previously unattainable. In contrast, all other gamma-cameras equipped with vacuum tubes have remained relatively unchanged for nearly fifty years. In these gamma-cameras, the images are obtained using two steps significantly less efficient: the gamma rays are converted to light through a first device, and then the light is converted into an electrical signal through a second device. One of functions the Medical Physicist is related to the quality control of equipment. This control ensures that the information and images provided are true and thus credible to be used in medical reports. To perform this type of analysis the physicist must understand the performance characteristics and operation of all equipment of the department concerned; besides, in the absence of specific legislation, proposing...(Complete abstract click electronic access below)

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A launching rocket and its payload are submitted to strong acoustic loads in some moments of its flight like lift off, during transonic flight and in the instant of maximum dynamic pressure. These loads could affect the payload and other rocket internal equipment. It must be taken into account that in the higher stages, where delicate control equipment and the payload are placed, the acoustic excitations are dominant. The knowledge of the acoustic loads is of great importance in order to provide estimated loads for the design phase, define intensity level to specify qualification and acceptation acoustic tests to which subsystems and elements of the launcher and its payload shall be submitted and to design an acoustic … (Complete abstract click electronic access below)

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Pós-graduação em Engenharia Elétrica - FEIS

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Pós-graduação em Engenharia Mecânica - FEIS

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No século XX, os famosos manifestos futuristas inauguraram, polemicamente e com muito ruído, as relações entre as artes (não apenas a literatura, portanto) e a ciência. Mas é sobretudo à tecnologia que os futuristas queriam atrelar as artes. Ao tentar transpor a velocidade das máquinas ao ritmo poético, Marinetti e outros futuristas realizaram operação que, por um lado, inegavelmente “dinamizou” a estrutura poética, por outro, atrelou mecanicamente, sem distanciamento crítico, o que era da esfera exclusiva da ciência e da tecnologia. Para os futuristas, exceção feita para as artes plásticas, o choque diante do advento do automóvel, do avião e dos demais produtos tecnológicos, frutos de um paciente e constante desenvolvimento da ciência a partir de Galileu, implicou em adequação mecânica e meramente estrutural, pelo menos no que diz respeito à poesia.

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Over the last few years, new technologies have been developed to making cavity preparations, among which the diamond burs CVDentus® (CVDentus, São José dos Campos, Brazil) are outstanding. These points are produced by chemical deposition from the vapor phase, forming a single diamond stone, with greater durability than the conventional diamond burs. Coupled to the ultrasound appliance, they have several clinical applications in Dentistry with advantages over conventional rotary instruments, such as lower pressure, noise, vibration and heat, as well as reducing the need to use local anesthesia, contributing to minimize patient’s fear and anxiety. The aim of this study was to present the complete restorative dental treatment performed with this system in a child patient with a prior history of non-cooperative behavior. The use of this new technology offered the patient greater comfort, making it possible recondition the patient’s attitude to dental treatment, in addition to favoring conservative cavity preparations to be made.

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PURPOSE: to analyze the levels of noise emitted by nationally-sold toys for use by children from 1 to 5 year old; to compare the values among the toys with and without the seal of Inmetro (National Institute of Metrology, Standardization and Industrial Quality) and to analyze the sound spectrum of toys, in order to identify the area of the cochlea that may be more affected by these noises. METHOD: measurements were performed on 20 sound toys (10 with the seal of the Inmetro and 10 without the seal) with the use of digital sound level meter in an acoustically treated room, and the sound analysis was performed using the Praat program. RESULTS: toys placed at 2.5 cm from the equipment with the seal of the Inmetro had an intensity ranging from 61.50 to 91.55 dB (A) and from 69.75 to 95.05 dB (C), positioned at 25 cm ranged from 58.3 to 79.85 dB (A) and from 62.50 to 83.65 dB (C). The results of the toys without warranty stamps placed at 2.5 cm ranged from 67.45 to 94.30 dB (A) and 65.4 to 99.50 dB (C) and the distance of 25 cm recorded from 61. 30 to 87.45 dB (A) and 63.75 to 97.60 dB (C), so that the findings demonstrated that there are noisy toys that go beyond the values recommended by the current legislation in both groups, with and without warranty stamps . CONCLUSION: the toys without the seal of Inmetro showed intensities values significantly higher than the other group, offering more risk to the children s hearing health.

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Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

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The development of electrocatalysts for the oxidation of methanol and ethanol is very important, because these alcohols may be used in the anode fuel cells which convert chemical energy directly into electrical energy with high efficiency, cleanly and with low noise. Thus, this study reports to the synthesis of nanocatalysts of PtAu supported on carbon by microemulsion method. The physical characterization of these catalysts is performed through the techniques of X-ray diffraction and transmission electron microscopy. The catalytic activity of the prepared materials was studied using conventional electrochemical techniques and also the technique of spectro-electrochemical in situ FTIR, which allows identification of intermediates and products of the reactions. From the x-ray diffraction, it was observed that the thermal treatment applied to catalysts favored incorporation of Au into the crystal lattice of Pt,that is, increased the formation of PtAu alloy. Micrographs indicated particle size about 3 nm to materials not heat treated and 9 nm to materials subjected to thermal treatment (heating at 150 ° C for 1h and 30 min in argon atmosphere). Current density oxidation of methanol on PtAu / C were superior to pure platinum. Spectroscopic results indicated the presence of formate in solution in 50:50 and the composition showed bands for CO2, indicating complete oxidation, in lower potential. During ethanol oxidation on the catalyst PtAu, the main product formed was acetate, product of incomplete oxidation. The good performance for methanol oxidation can be attributed to large amounts of oxygen species adsorbed on the catalyst surface, or an electronic effect.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Among the harmful health agents, it is given to the noise, one of the most present in urban and social environments. There are efficient measures to control the noise and the auricular Individual Protection Equipment (IPEa) is the most used. It has been observed the shortage in the comfortable and functional individual auditory protection products, related to durability, face to the efficiency right of the equipment. The main objective of this study was to recognize if there is effectiveness loss toward the used time on the Auditory Equipment, intra-auricular Individual Protection, of foam (3M), model 1110. It has been verified that the equipments suffer efficiency alteration according to the time of use, and the material consuming initiates reliable loss, mainly in audible frequencies going up to 100Hz, and from 16 days for sonorous pressure suffered started in 101dB 20Hz. For sonorous pressure suffered from 107dB to 20Hz, the reliable loss for the usage was of 8 days. The IPEas do not lose effectiveness on important attenuation by the daily use in frequencies from 1KHz until 20KHz. It has been concluded that there is effectiveness loss, according to the daily and frequent use of the IPEa studied.

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According to Statistical Yearbook of Social Security (2011), the number of accidents at work recorded in the agricultural sector is quite high, in the year 2010 there are records of thirty-four thousand nine hundred and ninetysix accidents, and in the year of 2011 there were thirty-one thousand and ninety-six accidents in the industry. Among so many diseases and accidents at work hearing loss is one of them. According to the Pan American Health Organization (2011) the Occupational hearing loss is then jury to the worker's health, often in the workplace. Mechanical vibrations are also present in many human activities exposing employees to an extremely aggressive agent. The combined action of these two factors can cause damage to the health of the worker, in this way, noise and vibration are the two major occupational agents present in the brush cutter operator activity. In the case there is another risk factor, the open work, which exposes the employee to the Sun’s rays and the high temperature indices. Studies have shown that: noise exceeds 115 dB (A) vibration 4.0 m/s2 and thermal stress of 29.9 o C. Ergonomic evaluations also demonstrated that the activity cause injury to workers.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Geografia - IGCE