937 resultados para Refração de ondas (Oceanografia)


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

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

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

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Ultrasound is the term that describes the sound waves with higher frequencies than human hearing. Ultrasound used in medical diagnosis is a modality based on the use of sound energy and the acoustic properties of the various parts of the body to produce images of stationary and moving tissues. However, despite the ease of use and security that this modality offers for not using ionizing radiation, one should ensure the accuracy and optimum performance of the equipment, which results in precise diagnoses. To accomplish that, periodic quality control tests must be performed, which include: physical and mechanical inspection of the equipment, image uniformity, depth of penetration/visualization, accuracy of distances, axial and lateral resolution, dead zone and doppler sensitivity. This work intends to study a computerized method for calculating the depth of penetration of ultrasound, comparing it to the observerdependent method currently used. The images were collected during the quality control tests of ultrasound equipment. The results of the comparison between the visual and computerized methods were not conclusive for selecting the safest methodology for obtaining the depth of visualization

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This scientific research aimed at presenting a comparative analysis of softwares used to represent the processes of flood wave and debris flow. For this, a literature review was performed on these processes and on simulation models used to represent them. Then, a research on scientific database and developers’ websites was performed to identify the softwares used to simulate these processes. This step was performed based on specific criteria such as the type of simulation performed by the software, its practical applications and a user friendly interface. A free distribution and totally functional software was chosen and its simulation mechanisms were tested through a simulation exercise and the results interpreted based on data on measured in the Basin of Ribeirão Marins section Monjolinho located in Piracicaba - SP. With respect to the processes, it was sought to present the dynamics, constraints, parameters and variables used to understand them and for the simulation models were presented the conceptual aspects of mathematical modeling including the steps of the simulation process and the different types of simulation models used to represent them. In total, 20 softwares were identified, and the software object of analysis was the ABC 6 that performs simulation of flood wave. Through the simulation exercise, it was observed that were presented overestimated values of flow compared to measured data in the basin. For both hypotheses were raised about the causes of the discrepancy between the observed and simulated flow. It has been concluded that the simulation process consisted of a complex procedure where generalizations, misrepresentations and simplifications may occur due to the data used and the method adopted, but it is a useful tool in planning and decision making in various types of studies and environmental projects

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Thin polymeric films deposited by plasma are very atractive for many industrial and scientific applications, in areas such as electronics, mechanics, coatings, biomaterials, among others, due to its favorable properties such as good adhesion to the substrate, high crosslinking, nanomectric thickness, homogeneity, etc. In this work, thin films were deposited by plasma immersion ion implantation and deposition technique from a hexamethyldisilazane/argon mixture at different proportions. These films were subjected to several characterizations, such as, contact angle, which presented values near to 100 degrees, surface energy, with values near to 31 mJ/m2, hardness with values between 0.7 and 2.6 GPa, thickness from 100 to 200 nm, refractive index from 1.56 to 1.64, molecular structure presenting the following functional groups in the infrared spectra region: CHx from 2960 to 2900 cm-1; Si-H around 2130 cm-1; CH3 in Si-(CH3)x around 1410 cm-1; CH3 in Si-(CH3)x in 1260 cm-1; N-H around 1180 cm-1; CH2 in Si-CH2-Si bonds around 1025 cm-1; Si-O in Si-O-Si from 1020 to 1100 cm-1; Si-N in Si-H-Si bonds around 940 cm-1; CH3 in Si-(CH3)3 in 850 cm-1; Si-C bonds in Si-(CH3)2 around 800 cm-1; and Si-H in 680 cm-1 . From these characterizations, it was possible to conclude that the concentration of argon or hexamethyldisilazane in the mixture changed the resulting polymer

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Through the data acquisition system of the instrument Brazilian Solar Spectroscope (BSS) at INPE, solar observations in the decimetric radio wave band (1000-2500 MHz) are regularly made. This data is showed as dynamic spectra using the software BSSView created for this purpose. The process of data acquisition can be influenced by various sources, dificulting the resulting dynamic spectrum analysis. The objective of this work is to create a computational routine that eliminates dynamic components of the spectrum attributed to interfering signals and integrate it into BSSView. It was done a preliminary study on the programming language Interactive Data Language (IDL), in which the BSSView was developed, and the Fourier transform, that is required for the application of the filter

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This paper presents a technique dubbed WiMAX radio link, the IEEE 802.16 was completed in October 2001 and published on April 8, 2002 and is constantly updated, this technology specifies an interface for wireless metropolitan networks (WMAN) and is under control of the WiMAX Forum, which is a group of companies responsible for the dissipation of this technology in the world, the great benefit of this standard is to offer broadband Internet connection in areas where there is no infrastructure such as fiber optics that has a cost higher. The main purpose of this paper is to present the theoretical and technical characteristics of this technology for both the standard for fixed and mobile standard, regulation of frequency bands by the FCC and description of the physical layer, through to basic concepts are used in many other types of radio link and technologies have been adapted and updated for this little-known standard, allowing a greater range and speed, which are specified and differentiate these advancements is one of the contributions of the work done here. After the theoretical conceptualization stage, a real case study has been inserted in this work to demonstrate the effectiveness of this technology deployed. The idea of presenting this case study is linked to a better view of the use of standard in the market, nationwide

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Due to the need of more agility, dynamism and reliability in stock management, the market has turned its attention to RFID, which offers a practical solution and live up to the big corporations' expectations. The search for continuous improvement establishes a direct link with RFID, for its technology offers accurate real time information in any monitored given place. RFID is a radio frequency communication technology. A reader communicates to a tag through waves. This tag can be active, with a battery, or passive, in which its power is supplied by currents induced by the field variation it is exposed to. The RFID technology has a well defined basic principle, but there are many constructive ways of implementing it. The adaptability as well as the flexibility regard to the several kinds of stock in industry, reaching their particular needs. RFID can lower maintenance costs in stock by collecting data more accurately, lowering human error and optimizing the item handling at its reception, exit and while it is inside the company. This paper presents an example of RFID technology applied in a company's stock management. It is possible to prove that there are, in fact, great advantages in implementing this technology, as it creates the opportunity for continuous improvement in stock management, with better application of material, labour and quality tools, since the data collected through an automatized process using RFID are more reliable and dynamic

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In many movies of scientific fiction, machines were capable of speaking with humans. However mankind is still far away of getting those types of machines, like the famous character C3PO of Star Wars. During the last six decades the automatic speech recognition systems have been the target of many studies. Throughout these years many technics were developed to be used in applications of both software and hardware. There are many types of automatic speech recognition system, among which the one used in this work were the isolated word and independent of the speaker system, using Hidden Markov Models as the recognition system. The goals of this work is to project and synthesize the first two steps of the speech recognition system, the steps are: the speech signal acquisition and the pre-processing of the signal. Both steps were developed in a reprogrammable component named FPGA, using the VHDL hardware description language, owing to the high performance of this component and the flexibility of the language. In this work it is presented all the theory of digital signal processing, as Fast Fourier Transforms and digital filters and also all the theory of speech recognition using Hidden Markov Models and LPC processor. It is also presented all the results obtained for each one of the blocks synthesized e verified in hardware

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The area chosen for this study is the island of Trinidade, which is located 1167 km off the Brazilian coast, in parallel Victory at 20 ° 30'S and 29 º 19'W, being the most easterly point of our continent. The isolation of oceanic island of Trinidade leaves no noticeable that she is part of a large submarine volcanic chain oriented east-west lineament known as Vitória- Trindade. Along with the island of Martin Vaz, who is Federal Territory is administered by the Navy of Brazil. Both correspond to Source alkaline volcanic islands. The area of the island of Trinidad has approximately 10 km2. Geologically consisting ankaratritic spills, spills tannbuschiticos, volcanic tuff spills analcite-ankaratrite, phonolite spills, spills nefelinite, pyroclastics, spills grazinite, tinguaitos, olivine-analcitito, calcarenite dunes and wind according to Almeida (1961). The island has its base on the ocean floor, at 5,800 m depth. It is the only place still recognizes preserved volcanic necks and plugs, as well as remnants of a volcano in Brazil. Magmatism occurred here a sodium alkali-silica subsaturated where his wrist was last 50,000 years according to Almeida (1961). It is a place with restricted access due to their distance from the coast, his contribution and hard to be an exclusive area of the Navy. On the island with peaks occur up to 620 meters high, and its rugged mountainous terrain and difficult access to very specific points, as the peak of Desire, peak Fazendinha, Monument and other points on the island. Because of its location far from the coast, its small infrastructure, difficulty of landing and restricted access by sea, the island of Trinidad offers no possibility of tourism, being a military outpost, and scientific basis of great importance, which conduct research in area of marine biology, oceanography, geology and others

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This work presents experimental results of some physical properties of antimony phosphate glasses with compositions (x) Sb2O3 - (1-x) P2O5 (x = 0.75, 0.85, 0.90). Mechanical, thermal, optical and electrical properties were investigated: density, elastic moduli (Young's moduli and Poisson's ratio), Vickers microhardness, coefficient of thermal expansion, glass transition temperature, refractive index and electrical conductivity (for x = 0.75). There was no evidence of electronic conductivity by bipolaron hopping. Measurements of energy dispersive spectroscopy (EDS) showed that volatilization of Sb2O3 takes place during the glass melting

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Environrnental issues are in focus lately, mainly due to climate change that have been registered in recent decades. Some of these changes are attributed to the increased atmospheric concentration of greenhouse gases induce, main1y due to anthropogenic emissions. These gases act by absorbing heat in the form of electromagnetic radiation emitted by the planet, and after a time interval, reissuing such radiation in various directions, including back to the surface, causing overheating of the same. Projections indicate that climate change wiIl tend to increase even more. Because of this, in recent years a number of studies are being conducted on the dynamics of inducers of greenhouse gases, especially C02, because that is primarily responsible for the development of that phenomenon. To better understand the flow of C02 are studied specific areas, as regions bordering the forests, soils that are under preparation for agriculture, urban areas, among others. Forests are an important sink for C02, because during the process of photosynthesis, this molecule is captured and used to obtain glucose. Thus, studies of the regions bordering the forests contribute enough to the understanding of the dynamics of C02. Because it requires a large amount of factors, the concentration of CO2 in a given location is very variable and this makes it much more difficult to understand their dynamics and, consequently, the action of the enhanced greenhouse effect. Being a relatively new area of study, there are many controversies about the consequences of the greenhouse effect, so that the community does not believe that climate change resulting from human action. According to them, such changes are merely natural phenomena and periodicals

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A Entomologia Forense é a ciência que aplica o estudo dos insetos, dentre outros artrópodes, a procedimentos legais, estando subdividida em três sub-áreas principais: Entomologia Urbana, Entomologia de Produtos Estocados e Entomologia Médico-Legal ou Médico-Criminal. A fauna entomológica cadavérica no Brasil apresenta uma ampla diversidade de espécies que se sucedem na carcaça, pois o processo de decomposição oferece condições ideais principalmente ao desenvolvimento dos dípteros, dentre outros insetos. A sucessão ecológica em carcaças ocorre em ondas de colonização, também denominada de sucessão ecológica de colonização de carcaças. A primeira onda, que é a mais importante para o presente estudo, inclui principalmente as moscas-varejeiras; dentre elas, merece destaque a espécie Chrysomya megacephala (Fabricius), um díptero da família Calliphoridae, que utiliza a carcaça para oviposição ou para alimentação dos adultos. Dos ovos eclodem as larvas, que se alimentam dos tecidos em decomposição, se desenvolvem e empupam no solo, nos arredores do cadáver, sendo assim possível estimar, a partir de evidências entomológicas, o tempo decorrido desde a morte até a descoberta de cadáveres humanos, ou seja, o intervalo pós-morte ou IPM, além de permitir obter informações do local onde possivelmente o crime tenha ocorrido, causa da morte, entre outros aspectos. Alguns trabalhos têm demonstrado que vários fatores podem afetar a determinação do IPM, tornando a investigação criminal mais difícil e, quando não forem levados em consideração, conduzem a erros no cálculo do IPM. Dispersão larval pós-alimentar, competição, predação, parasitismo, condições ambientais, e a presença de toxinas/drogas no corpo devem ser analisados em conjunto, de modo que erros na estimativa do IPM sejam minimizados tanto quanto possível. Deste modo, testes preliminares utilizando dietas artificiais em laboratório são...