A cor na pintura balinesa: caracterização dos pigmentos da pintura balinesa

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Conservação e Restauro

Time – intangible tangible –

Dissertação para obtenção do Grau de Mestre em Arte e Ciência do Vidro

O Mosteiro de Sta. Maria da Vitória e a vocação moralizante das gárgulas do panteão duartino

The Portuguese monument called Batalha’s monastery has occupied an important place in Art History especially the unfinished chapels destined to be the Pantheon of the King D. Duarte. There we observe some interesting gargoyles, moral representations as an approach to the late medieval imaginary in the national context, but also common with the thoughts of King D. Duarte. Gargoyles mirrored the daily life of medieval men and women and displayed the confrontation between the religious and the social spheres by criticizing the behaviour of the sinful body, taking on an important educational role amongst audiences. This article aims to understand the moral sense and sexual behaviour that can observe in these gargoyles and its relation with the book Leal Conselheiro, written by D. Duarte some decades before.

Photochemical control of rheology

The main objective of the research work developed in the framework of this PhD thesis was the preparation and development of novel photorheological fluids. This was pursued following two distinct strategies. The first one focused on the synthesis of tripodal compounds functionalized with photodimerizable moieties of cinnamic acid, coumarin and anthracene. Two sets of compounds were prepared, varying the central unit as well as spacers resulting in molecules with different solubilities and molecular weight. All compounds were characterized towards their photochemical properties and all exhibited photoreactivity upon irradiation with ultra-violet light. In particular, both coumarin derivatives exhibited the greatest photopolymerization reactivity, resulting in the formation of dendrimeric nanoparticles or in the increase of viscosity of organic solutions. The second strategy was focused on the careful design of photosensitive ionic liquids, based on the results of several quantitative structure-property relationship studies. Thus, photosensitive ionic liquids were synthesized bearing cinnamic acid or coumarin moieties in the organic cation. Upon irradiation, all compounds exhibited reactivity, which resulted in changes in their physical properties, such as melting point or viscosity. In addition, novel coumarin chromophores with different photophysical and photochemical properties were developed. It is expected that these compounds may find application in the preparation of new photosensitive ionic liquids.

A prestação de contas e o regime especial da invalidade das deliberações

The obligation of accountability, or the need to make known the economic and financial state of the companies, ceased to be a purely internal activity, becoming a necessity of a general nature. The knowledge of the financial state of the companies, wich is provided by accountability documents, reveals more and more elementary for all interested in the results obtained, whether in terms of profitability, either with a view to assessing the economic and financial health of the companies. This essay aims to a deeper analysis to matters of accountability, in particular, to the special invalidity scheme of corporate resolutions, wich is enshrined in art. 69º of Portuguese Companies Code. We chose to reference the accrual basis accounts approval, through the analysis of financial statements, laying down a set of principles and criteria applicable to different entities. After consideration of the special scheme versed in art. 69º, we conclude there is a certain ambiguity in the adoption of the criteria do delimit each of the hypotheses of the precept, since the legislator uses indeterminate concepts. Nevertheless, if there is a rule, this will be the annulment, and only exceptionally will apply the nullity scheme, where there is injury to the public interest and the interests of the creditors.

Using an LED as a sensor and visible light communication device in a smart illumination system

The need for more efficient illumination systems has led to the proliferation of Solid-State Lighting (SSL) systems, which offer optimized power consumption. SSL systems are comprised of LED devices which are intrinsically fast devices and permit very fast light modulation. This, along with the congestion of the radio frequency spectrum has paved the path for the emergence of Visible Light Communication (VLC) systems. VLC uses free space to convey information by using light modulation. Notwithstanding, as VLC systems proliferate and cost competitiveness ensues, there are two important aspects to be considered. State-of-the-art VLC implementations use power demanding PAs, and thus it is important to investigate if regular, existent Switched-Mode Power Supply (SMPS) circuits can be adapted for VLC use. A 28 W buck regulator was implemented using a off-the-shelf LED Driver integrated circuit, using both series and parallel dimming techniques. Results show that optical clock frequencies up to 500 kHz are achievable without any major modification besides adequate component sizing. The use of an LED as a sensor was investigated, in a short-range, low-data-rate perspective. Results show successful communication in an LED-to-LED configuration, with enhanced range when using LED strings as sensors. Besides, LEDs present spectral selective sensitivity, which makes them good contenders for a multi-colour LED-to-LED system, such as in the use of RGB displays and lamps. Ultimately, the present work shows evidence that LEDs can be used as a dual-purpose device, enabling not only illumination, but also bi-directional data communication.