A hybrid transport-diffusion model for radiative transfer in absorbing and scattering media

International audienceA new multi-scale hybrid transport-diffusion model for radiative transfer calculations is proposed. In this model, the radiative intensity is decomposed into a macroscopic component calculated by the diffusion equation, and a mesoscopic component. The transport equation for the mesoscopic component allows to correct the estimation of the diffusion equation, and then to obtain the solution of the linear radiative transfer equation. In this work, results are presented for stationary and transient radiative transfer cases, in examples which concern solar concentrated and optical tomography applications. The Monte Carlo and the discrete-ordinate methods are used to solve the mesoscopic equation. It is shown that the multi-scale model allows to improve the efficiency of the calculations when the medium is close to the diffusive regime. Moreover, the development of methods for coupling the radiative transfer equation with the diffusion equation becomes easier with this model than with the usual domain decomposition methods

Parylene C as a Multipurpose Material for Electronics and Microfluidics

Funding Information: This work was financed by national funds from FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the projects LA/P/0037/2020, UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication—i3N. Furthermore, the work received funding from FCT in the scope of projects UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB. This work also received funding from the European Community’s H2020 program under grant agreements 716510 (ERC-2016-StG TREND), 787410 (ERC-2019-AdG DIGISMART) and 952169 (SYNERGY, H2020-WIDESPREAD-2020-5, CSA), 101008701 (EMERGE, H2020-INFRAIA-2018-2020). B. J. Coelho acknowledges FCT for the attribution of grant SFRH/BD/132904/2017 and grant COVID/BD/152453/2022. Publisher Copyright: © 2023 by the authors.Poly(p-xylylene) derivatives, widely known as Parylenes, have been considerably adopted by the scientific community for several applications, ranging from simple passive coatings to active device components. Here, we explore the thermal, structural, and electrical properties of Parylene C, and further present a variety of electronic devices featuring this polymer: transistors, capacitors, and digital microfluidic (DMF) devices. We evaluate transistors produced with Parylene C as a dielectric, substrate, and encapsulation layer, either semitransparent or fully transparent. Such transistors exhibit steep transfer curves and subthreshold slopes of 0.26 V/dec, negligible gate leak currents, and fair mobilities. Furthermore, we characterize MIM (metal–insulator–metal) structures with Parylene C as a dielectric and demonstrate the functionality of the polymer deposited in single and double layers under temperature and AC signal stimuli, mimicking the DMF stimuli. Applying temperature generally leads to a decrease in the capacitance of the dielectric layer, whereas applying an AC signal leads to an increase in said capacitance for double-layered Parylene C only. By applying the two stimuli, the capacitance seems to suffer from a balanced influence of both the separated stimuli. Lastly, we demonstrate that DMF devices with double-layered Parylene C allow for faster droplet motion and enable long nucleic acid amplification reactions.publishersversionpublishe

Microwave hydrodiffusion and gravity: an emergent technology for green extraction of non-volatile compounds

Microwave technologies are more and more present in food applications due to their performance in shortening the time of treatments such as drying, pasteurization, defrosting, or postharvesting. While solvent-free microwave extraction has been extensively used as a green procedure for essential oil and volatile compounds from aromatic herbs [1], its applications have been extended to enhance extraction of phytocompounds simultaneously with drying. In this work, microwave hydrodiffusion and gravity was performed in a laboratory microwave oven (NEOS-GR, Milestone, Italy), in order to evaluate its efficiency in the extraction of nonvolatile compounds such as: free sugars, f1bers, colour, and phenolic compounds. Five different matrices were tested: broccoli by-products (90% moisture), apple pomace (80% moisture), spent coffee grounds (65% moisture), Pterospartum tridentatum inflorescences, and brown algae, the latter two in dried state. The flow behaviour was very dependent on matrix (Figure 1): for broccoli, the time to obtain 50 ml aliquots increased along time while for apple pomace it was always the same after the initial and final heating periods, and for the spent coffee grounds it was always decreasing. Good recoveries were observed when using high water content matrices, such as apple pomace and broccoli. However, when using hydrated matrices, such as brown algae and Pterospartum tridentatum inflorescences, it was observed that the amount of material extracted is very low. In the case of spent coffee qrounds (a material where water is added to the ground coffee when preparing espresso coffee), the initial low recoveries can be overcome by the eo-addition of ethanol, allowing to obtain fractions rich in phenolic compounds, as well as brown compounds (with antioxidant activity) and caffeine. NEOS-GR, using microwave hydrodiffusion and gravity is a green extraction technology obtain hydrophilic compounds from wet matrices using its own water, allowing the extraction of valuable non-volatile compounds.info:eu-repo/semantics/publishedVersio

Microwave hydrodiffusion and gravity: an emergent technology for green extraction of non-volatile compounds

Microwave technologies are more and more present in food applications due to their performance in shortening the time of treatments such as drying, pasteurization, defrosting, or post-harvesting [1]. While solvent-free microwave extraction has been extensively used as a green procedure for essential oil and volatile compounds from aromatic herbs [2], its applications have been extended to enhance extraction of phytocompounds simultaneously with drying. In microwave drying, operational cost is lower because energy is not consumed in heating the walls of the apparatus or the environment [3].info:eu-repo/semantics/publishedVersio

HERA - Environmental Risk Assessment of a contaminated estuarine environment: a case study

Sado River estuary is located in the west coast of Portugal. Previous environmental studies identified industrial contamination, non-point anthropogenic sources and contamination coming from the river, all promoting accumulation of polluted sediments with known impacts on the ecological system. Surrounding human populations have intense economic fishery activities. Together with agriculture, estuary fishing products are available to local residents. Food usage previously characterized through ethnographic studies suggests exposure to estuarine products, farming products, and water in daily activities, as potential routes of contamination. It is well established that long term exposure to heavy metals are associated with renal and neurological diseases, most heavy metals are classified as carcinogenic and teratogenic.Instituição Financiadora: FCT; Instituições participantes: IMAR -Instituto do Mar (coord.)e PRÓ-INSA, Associação para a Promoção da Investigação em Saúde, Instituto Nacional de Saúde Doutor Ricardo Jorg

Manual de boas práticas e sustentabilidade no turismo

info:eu-repo/semantics/publishedVersio

Práticas artísticas no ensino básico e secundário

A educação pela arte faz-se através dos seus materiais, da sua operação, da transformação das matérias em ideias novas, em novas coisas. No seu sucesso está implicada uma literacia, uma capacidade interpretativa, ou crítica, sobre a semiosfera cada vez mais povoada, saturada de mensagens parasitárias. A educação implica uma leitura do mundo (Paulo Freire), que se projeta na interpretação de todas as camadas de expressão contemporânea, muitas vezes massificada, por vezes ainda identitária e significativa. Fala-se aqui de valorizar a identidade, exercer a pedagogia da diferença através de uma capacidade problematizadora. No seu contexto, podem exercer-se pedagogias que exploram a visão crítica do artista em interação com a escola, o artista em residência, no movimento A/ R/ Tography. Ou também exercer-se uma pedagogia triangular, centrando a arte, o contexto, a produção e a sua leitura como uma metodologia (Ana Mae Barbosa). O contexto contemporâneo é pós digital, os conteúdos não pesam nos suportes, e transmitem-se por “dentes azuis” ou redes com muitos Gs (G de Geração sem peso que sucede ao peso da aceleração gravítica). Neste campo pode delinear-se uma metodologia que alicerça o projeto ancorado nos estudos críticos sobre Cultura Visual (Fernando Hernández). Digamos que as práticas pedagógicas se cruzam em diversas direções, tacteando eficácias, expressões, capacidades, inovação. O contexto é cada vez mais voraz: a pele da cultura gosta de massagens (Kerkhove; McLuhan). A Matéria-Prima de que se fala nesta revista é aquela que devolve ao seu lugar um ponto crítico da pós modernidade: o do significante. Os sintagmas são sempre processos, e neles se formam as subjectividades, ou seja, as identidades: no desenrolar do ser, onde se produz verdadeiramente o sentido, bem junto do aqui-e-agora onde está a Matéria-Prima (Foucault).info:eu-repo/semantics/publishedVersio