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Made available in DSpace on 2014-12-17T14:57:51Z (GMT). No. of bitstreams: 1 MarcoASR_TESE.pdf: 5586767 bytes, checksum: d92d904a4f89177a814a13f5f7230b94 (MD5) Previous issue date: 2011-07-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In this study were conducted experimental procedures for determination of variation of the expandability of rigid polyurethane foam (PUR) from a natural oil polyol (NOP), specifically the Castor oil plant, Ricinus communis, pure and additions of the vermiculite in phase dispersed in different percentage within a range from 0% to 20%, mass replacement. From the information acquired, were defined the parameters for production of bodies of test, plates obtained through controlled expansion, with the final volume fixed. Initially, the plates were subjected to thermal performance tests and evaluated the temperature profiles, to later be extracted samples duly prepared in accordance with the conditions required for each test. Was proceeded then the measurement of the coefficient of thermal conductivity, volumetric capacity heat and thermal diffusivity. The findings values were compared with the results obtained in the tests of thermal performance, contributing to validation of the same. Ultimately, it was investigated the influence that changes in physical-chemical structure of the material had exerted on the variation of thermophysical quantities through gas pycnometry, scanning electron microscopy (SEM) combined with energy dispersive X-ray fluorescence spectroscopy (EDXRF), infrared spectroscopy using Fourier transform (FTIR), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Based on the results obtained was possible to demonstrate that all load percentage analyzed promoted an increase in the potential expansion (PE) of the resin. In production of the plates, the composites with density near at the free expansion presented high contraction during the cure, being the of higher density adopted as definitive standard. In the thermal performance tests, the heating and cooling curves of the different composites had presented symmetry and values very close for lines of the temperature. The results obtained for the thermophysical properties of composites, showed little difference in respect of pure foam. The percentage of open pores and irregularities in the morphology of the composites were proportionate to the increment of vermiculite. In the interaction between the matrix and dispersed phase, there were no chemical transformations in the region of interface and new compounds were not generated. The composites of PUR-NOP and vermiculite presented thermal insulating properties near the foam pure and percentage significantly less plastic in its composition, to the formulation with 10% of load / Neste estudo, foram realizados procedimentos experimentais para determina??o da varia??o da expansibilidade da espuma r?gida de poliuretano (PUR) de um poliol de ?leo natural (NOP), especificamente o de mamona, Ricinus communis, puro e acrescido de vermiculita na fase dispersa, em distintos percentuais, dentro de uma faixa de 0% a 20%, de substitui??o em massa. A partir das informa??es adquiridas, foram definidos os par?metros para produ??o dos corpos de prova, placas obtidas atrav?s de expans?o controlada, com volume final fixo. Inicialmente, as placas foram submetidas a testes de desempenho t?rmico, sendo avaliados os perfis de temperatura, para posteriormente serem extra?das amostras, devidamente preparadas conforme as condi??es exigidas para cada ensaio. Procedeu-se ent?o a medi??o do coeficiente de condutividade t?rmica, capacidade t?rmica volum?trica e difusividade t?rmica. Os valores encontrados foram comparados com os resultados obtidos nos testes de desempenho t?rmico, contribuindo para valida??o dos mesmos. Por fim, foi investigada a influ?ncia que as altera??es na estrutura f?sico-qu?mica do material, exerceram sobre a varia??o das grandezas termof?sicas, por meio de picnometria a g?s, microscopia eletr?nica de varredura (MEV) combinada com espectroscopia de fluoresc?ncia de raios-X por energia dispersiva (EDXRF), espectroscopia de infravermelho com transformada de Fourier (FTIR), an?lise termogravim?trica (TGA) e an?lise t?rmica diferencial (DTA). Com base nos resultados obtidos foi poss?vel demonstrar que todos os percentuais de carga analisados promoveram um aumento do potencial de expans?o (PE) da resina. Na produ??o das placas, os comp?sitos com densidade pr?xima ? expans?o livre apresentaram grande contra??o na cura, sendo adotados os de maior densidade como padr?o definitivo. Nos ensaios de desempenho t?rmico, as curvas de aquecimento e resfriamento dos diferentes comp?sitos apresentaram simetria e valores muito pr?ximos para as linhas de temperatura. Os resultados obtidos para as propriedades termof?sicas dos comp?sitos, demonstraram pouca diferen?a em rela??o aos da espuma pura. O percentual de poros abertos e irregularidades na morfologia dos comp?sitos foram proporcionais ao incremento da vermiculita. Na intera??o entre matriz e fase dispersa n?o ocorreram transforma??es qu?micas na regi?o de interface e n?o foram gerados novos compostos. Os comp?sitos de PUR-NOP e vermiculita apresentaram propriedades isolantes t?rmicas pr?ximas as da espuma pura e percentual significativamente menor de pl?stico em sua composi??o, para a formula??o com 10% de carga

There are several frauds against biometric systems (BSs) and several techniques exist to secure BSs against these frauds. One of the techniques is liveness detection. To fool fingerprint sensors, latent fingerprints, dummy fingers and wafer-thin layer attached to the finger are being used. Liveness detection is being used also when scanning fingerprints. Several different characteristics of the live finger can be used to detect liveness, for example sweat, conductivity etc. In this thesis, new approach is examined. It is based on the expandability of the finger as an effect of heartbeats/pulsation. As the skin is expanding, also the distances between papillary lines are expanding. Whole finger expands approximately in range of 4,5 ľm , the distance between two neighbor papillary lines in 0,454 ľm . This value collides with wavelength of blue and green light. The result from this work is following. The resolution of the capturing device is not high enough to capture the expandability on distance between two neighbor papillary lines. Also, because of collision with wavelength, the diffraction effect is presented and the result images are influenced by this error.