996 resultados para Laser processing


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Since the invention of photography humans have been using images to capture, store and analyse the act that they are interested in. With the developments in this field, assisted by better computers, it is possible to use image processing technology as an accurate method of analysis and measurement. Image processing's principal qualities are flexibility, adaptability and the ability to easily and quickly process a large amount of information. Successful examples of applications can be seen in several areas of human life, such as biomedical, industry, surveillance, military and mapping. This is so true that there are several Nobel prizes related to imaging. The accurate measurement of deformations, displacements, strain fields and surface defects are challenging in many material tests in Civil Engineering because traditionally these measurements require complex and expensive equipment, plus time consuming calibration. Image processing can be an inexpensive and effective tool for load displacement measurements. Using an adequate image acquisition system and taking advantage of the computation power of modern computers it is possible to accurately measure very small displacements with high precision. On the market there are already several commercial software packages. However they are commercialized at high cost. In this work block-matching algorithms will be used in order to compare the results from image processing with the data obtained with physical transducers during laboratory load tests. In order to test the proposed solutions several load tests were carried out in partnership with researchers from the Civil Engineering Department at Universidade Nova de Lisboa (UNL).

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The mobile IT era is here, it is still growing and expanding at a steady rate and, most of all, it is entertaining. Mobile devices are used for entertainment, whether social through the so-called social networks, or private through web browsing, video watching or gaming. Youngsters make heavy use of these devices, and even small children show impressive adaptability and skill. However not much attention is directed towards education, especially in the case of young children. Too much time is usually spent in games which only purpose is to keep children entertained, time that could be put to better use such as developing elementary geometric notions. Taking advantage of this pocket computer scenario, it is proposed an application geared towards small children in the 6 – 9 age group that allows them to consolidate knowledge regarding geometric shapes, forming a stepping stone that leads to some fundamental mathematical knowledge to be exercised later on. To achieve this goal, the application will detect simple geometric shapes like squares, circles and triangles using the device’s camera. The novelty of this application will be a core real-time detection system designed and developed from the ground up for mobile devices, taking into account their characteristic limitations such as reduced processing power, memory and battery. User feedback was be gathered, aggregated and studied to assess the educational factor of the application.

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INTRODUÇÃO: Pirajá da Silva fez contribuição magnífica à helmintologia ao descrever ovos de Schistosoma mansoni nas fezes de um paciente, no Estado da Bahia e a morfologia de vermes adultos. MÉTODOS: Neste estudo, apresentamos uma avaliação microscópica das lâminas montadas e depositadas na Coleção Helmintológica do Instituto Oswaldo Cruz. A técnica empregada nesta nova análise foi a microscopia de varredura a laser confocal. RESULTADOS: Na parte anterior dos vermes adultos machos, observamos ventosas com musculatura bem desenvolvida e células germinativas dentro dos lobos testiculares. Visualizamos, também, espinhos localizados na região mediana do canal ginecóforo. Na superfície dorsal, encontramos tubérculos e feixes musculares transversais e longitudinais. Em relação ao aparelho reprodutivo feminino, pudemos distinguir um ovo no interior do útero e o ovário alongado com células germinativas. As glândulas vitelínicas estavam restritas à parte posterior das fêmeas conectadas por um ducto vitelínico curto. CONCLUSÕES: As características morfológicas são similares as estudadas anteriormente por Pirajá da Silva com vermes frescos. Além disso, este estudo demonstra a importância de se depositar espécimes nas coleções helmintológicas abrindo possibilidade de novos estudos com estas lâminas.

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Herpes simplex virus types 1 and 2 are the main infectious agents associated with oral and genital ulcerations. These infections are now widely recognized as sexually transmitted diseases. Among treatment options, low-level laser therapy (LLLT) has shown promising clinical results as a longer-lasting suppression therapy. Two clinical cases are described with recurrent labial herpes for which LLLT was used. Following treatment, both patients remained symptom free during the 17-month clinical follow-up period.

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Viral vectors are playing an increasingly important role in the vaccine and gene therapy elds. The broad spectrum of potential applications, together with expanding medical markets, drives the e orts to improve the production processes for viral vaccines and viral vectors. Developing countries, in particular, are becoming the main vaccine market. It is thus critical to decrease the cost per dose, which is only achievable by improving the production process. In particular advances in the upstream processing have substantially increased bioreactor yields, shifting the bioprocess bottlenecks towards the downstream processing. The work presented in this thesis aimed to develop new processes for adenoviruses puri cation. The use of state-of-the-art technology combined with innovative continuous processes contributed to build robust and cost-e ective strategies for puri cation of complex biopharmaceuticals.(...)

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We are constantly immersed in stimuli. Upon reaching our senses, stimuli are processed within various brain systems along various pathways into the brain, and eventually turned into a percept. However, there are percepts that do not result from responses to external source stimuli. A particular case of this situation is the auditory percept known as tinnitus. Tinnitus can be seen as a task-irrelevant auditory percept, commonly reported to interfere with normal daily tasks. This is known from reports made by tinnitus sufferers that refer to their phantom percept as distracting, and that it diverts their focus from the task-relevant stimuli.(...)

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In this study in the field of Consumer Behavior, brand name memory of consumers with regard to verbal and visual incongruent and congruent information such as memory structure of brands was tested. Hence, four experimental groups with different constellations of verbal and visual congruity and incongruity were created to compare their brand name memory performance. The experiment was conducted in several classes with 128 students, each group with 32 participants. It was found that brands, which are presented in a congruent or moderately incongruent relation to their brand schema, result in a better brand recall than their incongruent counterparts. A difference between visual congruity and moderately incongruity could not be confirmed. In contrast to visual incongruent information, verbal incongruent information does not result in a worse brand recall performance.

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This dissertation analyzes the possibilities of utilizing speech-processing technologies to transform the user experience of ActivoBank’s customers while using remote banking solutions. The technologies are examined through different criteria to determine if they support the bank’s goals and strategy and whether they should be incorporated in the bank’s offering. These criteria include the alignment with ActivoBank’s values, the suitability of the technology providers, the benefits these technologies entail, potential risks, appeal to the customers and impact on customer satisfaction. The analysis suggests that ActivoBank might not be in a position to adopt these technologies at this point in time.

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The work described in this thesis was performed at the Laboratory for Intense Lasers (L2I) of Instituto Superior Técnico, University of Lisbon (IST-UL). Its main contribution consists in the feasibility study of the broadband dispersive stages for an optical parametric chirped pulse amplifier based on the nonlinear crystal yttrium calcium oxi-borate (YCOB). In particular, the main goal of this work consisted in the characterization and implementation of the several optical devices involved in pulse expansion and compression of the amplified pulses to durations of the order of a few optical cycles (20 fs). This type of laser systems find application in fields such as medicine, telecommunications and machining, which require high energy, ultrashort (sub-100 fs) pulses. The main challenges consisted in the preliminary study of the performance of the broadband amplifier, which is essential for successfully handling pulses with bandwidths exceeding 100 nm when amplified from the μJ to 20 mJ per pulse. In general, the control, manipulation and characterization of optical phenomena on the scale of a few tens of fs and powers that can reach the PW level are extremely difficult and challenging due to the complexity of the phenomena of radiation-matter interaction and their nonlinearities, observed at this time scale and power level. For this purpose the main dispersive components were characterized in detail, specifically addressing the demonstration of pulse expansion and compression. The tested bandwidths are narrower than the final ones, in order to confirm the parameters of these elements and predict the performance for the broadband pulses. The work performed led to additional tasks such as a detailed characterization of laser oscillator seeding the laser chain and the detection and cancelling of additional sources of dispersion.

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Apesar do elevado potencial do metal magnésio como material útil em várias áreas cien-tíficas e tecnológicas, os seus métodos de produção tradicionais têm um impacto fortemente prejudicial no ambiente e um custo elevado. Este facto é um incentivo à procura de novas so-luções, nomeadamente as que recorrem à utilização da radiação solar partindo do óxido de magnésio. Alguns estudos têm já sido feitos nesse sentido, utilizando laser solar ou radiação solar concentrada mas a utilização concertada dos dois não tinha sido feita até ao momento. Neste trabalho, a exequibilidade da utilização concertada destes dois métodos será avaliada e será estudado o comportamento do óxido de magnésio face à radiação que nele incide.

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O revestimento com laser permite criar revestimentos localizados pela adição de uma liga similar ou dissimilar. O revestimento visa melhorar as características da superfície metálica, tais como a dureza, a resistência ao desgaste por atrito, à corrosão e à fadiga térmica dos componentes sujeitos a condições adversas de trabalho por prolongados períodos de tempo. Esta dissertação tem como objetivo o melhoramento da configuração, a automatização do sistema de revestimento com laser do Laboratório de Laser do Instituto Superior Técnico (IST) da Universidade de Lisboa, utilizado pelo Centro de Física e Engenharia de Materiais Avançados do Instituto Superior Técnico – CeFEMA e a realização de ensaios de deposições com o fim de validação. Foram estudadas as configurações possíveis para o sistema de posicionamento da amostra, do laser e a configuração para o posicionamento com precisão do bocal de adição de pós ao banho de fusão. Após este estudo foram apresentadas e implementadas as propostas de melhoria do sistema inicial. Para tornar o sistema funcional, foi desenvolvido um controlador para comandar as três guias motorizadas de movimento linear OWIS, o laser IPG YLR e o alimentador de pós PLASMA-TECHNIK. Para simplificar a utilização aos investigadores do CeFEMA foi ainda desenvolvida uma interface gráfica que permite ao utilizador definir os principais parâmetros do processo Para a validação do trabalho desenvolvido foram realizados diversos ensaios de deposição da liga Ti52Ta num substrato de titânio. Através dos ensaios de deposição foi estudada a influência de alguns parâmetros do processo na geometria do revestimento obtido, como a altura, a profundidade, o ângulo do cordão, a diluição entre o material de adição e o substrato, tendo ainda sido estudada a influência dos parâmetros do processo na eficiência de deposição.

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Welle Laser is a Brazilian company that manufactures marking and engraving machines mainly for large-scale industry segments providing solutions that help increase productivity. Welle laser has 60% market share in Brazil and decided to go internationally in 2015, mainly to increase revenues and diversify business risks. Welle opened an office in Switzerland and celebrated a contract with a Mexican company to distribute their machines in Mexico. The next step for Welle is expanding its operation to USA. In my project I accessed the viability and reasons to enter the US market, the region where Welle should start its operation, and the best entry mode strategy.

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As increasingly more sophisticated materials and products are being developed and times-to-market need to be minimized, it is important to make available fast response characterization tools using small amounts of sample, capable of conveying data on the relationships between rheological response, process-induced material structure and product characteristics. For this purpose, a single / twin-screw mini-extrusion system of modular construction, with well-controlled outputs in the range 30-300 g/h, was coupled to a in- house developed rheo-optical slit die able to measure shear viscosity and normal-stress differences, as well as performing rheo-optical experiments, namely small angle light scattering (SALS) and polarized optical microscopy (POM). In addition, the mini-extruder is equipped with ports that allow sample collection, and the extrudate can be further processed into products to be tested later. Here, we present the concept and experimental set-up [1, 2]. As a typical application, we report on the characterization of the processing of a polymer blend and of the properties of extruded sheets. The morphological evolution of a PS/PMMA industrial blend along the extruder, the flow-induced structures developed and the corresponding rheological characteristics are presented, together with the mechanical and structural characteristics of produced sheets. The application of this experimental tool to other material systems will also be discussed.

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Wool and silk are major protein fiber materials used by the textile industry. Fiber protein structure-function relationships are briefly described here, and the major enzymatic processing routes for textiles and other novel applications are deeply reviewed. Fiber biomodification is described here with various classes of enzymes such as protease, transglutaminase, tyrosinase, and laccase. It is expected that the reader will get a perspective on the research done as a basis for new applications in other areas such as cosmetics and pharma.