Search

Model-Based Systems Engineering (MBSE) is an adopted modelling and development approach for correct-by- construction of complex software systems, such as space applications. TASTE [1] is a pragmatic and mature MBSE toolset supported by ESA that enables and provides automation for most of the phases of software system development: (i) heterogeneous system design through several modelling and programming languages (e.g., ASN.1, AADL, SDL, C/C++), (ii) code generation, build and deployment of the binary application(s), (iii) validation through static analysis and simulation, and (iv) formal verification of properties by model-checking. The formal verification capabilities have been recently added to the TASTE toolset in the ESA project Model-Checking for Formal Verification of Space Systems (MoC4Space) and validated on two real-life case studies. Within this paper we report on the results and lessons learned during the project.

Made available in DSpace on 2018-08-29T15:57:03Z (GMT). No. of bitstreams: 1 4157_7993.pdf: 1971415 bytes, checksum: 407c14ee7a0a660d75ca3f4a2c17356a (MD5) Previous issue date: 2015-06-23

The estimated equilibrium melting points of the poly(e-caprolactone) (PCL) fraction in poly(styrene-co-maleic anhydride)/poly(e-caprolactone) blends (PSMA14/PCL), where the PSMA has 14 mol% of maleic anhydride units, were successfully analyzed by means of the Nishi-Wang equation yielding a negative Flory-Huggins interaction parameter ( c = -1.46 ). This result indicates strong interactions between the blend components, whose magnitude do not change with composition. The kinetics of the PCL spherulitic growth was investigated as a function of composition and crystallization temperature by polarized optical microscopy and analyzed using the traditional Lauritzen-Hoffman (LH) secondary nucleation theory, as well as a modified version of it. The composition dependence of nucleation constants, Kg, in crystal growth regime II suggests that crystal fold energy, se, decreases with the addition of PSMA14, but when the concentration of PSMA14 reaches 20% or more, non additional effect is observed, a fact that was attributed to the PCL effective concentration considered in the Lodge and McLeisch model for miscible blends Mediante la ecuación de Nishi-Wang se llevó a cabo en este trabajo un análisis de los puntos de fusión en equilibrio estimados de la fracción de poli(e-caprolactona) (PCL) contenida en mezclas de poli(estireno-co-anhídrido maleico)/poli(e-caprolactona) (PSMA14/PCL), donde el PSMA posee 14% molar de unidades de anhídrido maleico. Como resultado se obtuvo un parámetro de interacción de Flory-Huggins negativo (c = -1.46), resultado que indica la existencia de fuertes interacciones entre los componentes de la mezcla, cuya magnitud no cambia con la composición. La técnica de microscopía óptica de luz polarizada permitió estudiar la cinética de crecimiento esferulítico de la PCL en función de la composición y de la temperatura de cristalización. Posteriormente, se aplicó la tradicional teoría de nucleación secundaria de Lauritzen-Hoffman (LH), así como también una de sus versiones modificadas. La dependencia de las constantes de nucleación, Kg, con la composición en el régimen de crecimiento II sugiere que la energía de pliegue disminuye con la adición de PSMA14. Sin embargo, cuando la concentración de PSMA14 alcanza el 20% o más, no se observa efecto adicional, hecho que se atribuyó a la concentración efectiva de PCL que se considera en el modelo de Lodge y McLeisch para mezclas miscibles

Dada la versatilidad de la Policaprolactona (PCL) para la elaboración de mezclas poliméricas, éste polímero fue mezclado con un componente amorfo, el Poli(Estireno-co-Anhídrido Maleico) (SMA) con 14% p/p de anhídrido maleico (SMA14). Se encontró que el sistema SMA14/PCL es miscible en la zona amorfa en todo el rango de composiciones, demostrándose mediante Espectroscopia Infrarroja por Transformada de Fourier y Resonancia Magnética Nuclear que tal miscibilidad es producto de interacciones físicas y no de reacciones químicas entre los componentes. El comportamiento térmico de este sistema depende de la composición, siendo posible la obtención de mezclas que cristalizan durante el enfriamiento, mezclas que no cristalizan y mezclas que cristalizan en frío. La miscibilidad se refleja en la depresión de la temperatura de fusión y cristalización de la fracción de PCL a medida que se incrementa el contenido de SMA14, y la presencia de una única Tg ubicada a temperaturas intermedias a las de los polímeros puros, las cuales se ajustan bien a lo predicho por la ecuación de Fox, especialmente a altos contenidos de SMA14. Los resultados morfológicos mostraron la formación de esferulitas con banding sin evidencias de segregación interesferulítica del componente amorfo producto del mezclado de los componentes a nivel molecular. Due to the versatility of the Polycaprolactone (PCL) for the preparation of polymer blends, we blended it with an amorphous component, Poly(Styrene-co-Maleic Anhydride) (SMA) containing 14% wt of maleic anhydride. We found that the polymer blend system SMA14/PCL is miscible in the amorphous region in the whole composition range. It was demonstrated through Fourier Transformed Infrared Spectroscopy and Nuclear Magnetic Resonance that such miscibility results from physical interactions and not from chemical reactions between the components. The thermal behaviour of this system depends on composition, with a variety of results from blends that crystallize on cooling, blends that do not crystallize to blends that cold-crystallize. The miscibility leads to a depression of the melting and crystallization temperatures of the PCL fraction as the SMA14 content increases. The existence of a single Tg located at temperatures in between those of the neat polymers evidences the miscibility on a macroscopic scale. These temperatures can be well predicted by using the Fox equation, especially for high SMA14 contents. The morphological results showed the formation of banded spherulites without interspherulitic segregation of the amorphous component as a result of the molecular mixing of the components.

Dissertação de mestrado em Ciências da Comunicação (área de especialização em Informação e Jornalismo), Esta dissertação parte da experiência do estágio curricular desenvolvido na Revista Projetar Casa Magazine, uma publicação online sobre arquitetura, design e decoração. Portanto, o mote está dado, uma das matérias primordiais e que está no “epicentro” da esfera dos Media é todo este processo de migração que se tem registado nos últimos anos para a esfera digital. Este contato com a área, como estagiária, suscitou diversas dúvidas e questões de trabalho, numa experiência diária de como é, e o que significa trabalhar a partir do e para o universo digital. Assim sendo, a primeira parte deste relatório de estágio consiste na narração das tarefas e experiências que vivi enquanto estagiária, uma espécie de viagem até ao mês de setembro, onde serão descritas todas as etapas decorrentes destes três meses de estágio profissionalizante. Na segunda parte será apresentada uma parte mais teórica, com reflexão mais aprofundada sobre este tema, com especial enfoque nas novas exigências que este novo jornalismo - o jornalismo online - trouxe para o panorama atual., This dissertation is based on the experience of a curricular training developed in Projetar Casa Magazine, an online publication of architecture, design and decoration. Therefore, the theme is given, one of the primary issues that is at the "epicentre" of the media sphere is the whole process of migration that has occurred in recent years for the digital realm. This contact with the area as a trainee, raised several concerns and working issues, in a daily experience of how it was and what it meant to work from and to the digital universe. Thus, the first part of this probation report is intended to describe the tasks and experiences that I have experienced during the three months of professional training period. Afterwards, it will be presented a more theoretical part, with a deeper reflection on the theme, with special focus on new requirements that the new journalism - online journalism - has brought to the current communication panorama.