Sapientia
Repositório Científico da UAlg
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Validation of industrial waste blast furnace slag and copper slag as replacement of cement and aggregates in concrete
Publication . Parrón-Rubio, M. E.; Lima-Rodríguez, A. M.; Oliveira, Miguel José; Pérez-García, F.; Rubio-Cintas, M. D.; Rubio-Hernández, F. J.
The combined use of ground granulated blast furnace slag (GGBFS) and copper slag (CS) in concrete was investigated. Three mixes were assessed: a reference concrete and two blended-slag concretes with 50% cement replacement by GGBFS and 60–100% replacement of the medium aggregate by CS. Fresh-state was characterized by slump testing and absolute rheometry. Hardened performance was evaluated through compressive and flexural strength, density–porosity–water absorption, capillary suction, abrasion resistance, shrinkage, and carbonation resistance. The mixture containing 50% GGBFS and 60% CS achieved the best overall performance, reaching approximately 78 MPa at 90 days and showing the lowest porosity, water absorption and capillary suction. SEM–EDS and XRD revealed a compact matrix containing calcite, dolomite and hydrotalcite. Leaching results showed low trace-element release, while the preliminary carbon-footprint assessment indicated a 42.6% reduction compared with the reference concrete. These results support the controlled use of GGBFS and CS in durable, lower-impact concrete.
From clinical theory to user reality: A multi-phase co-design protocol of an analog serious game for fall prevention
Publication . Tome, Ana Maria; Tomás, Maria Teresa; Pais, Sandra; de Almeida Fontes, Ana Paula; Rosa, Marlene
Introduction: Developing serious games for geriatric rehabilitation requires bridging the gap between clinical guidelines and user engagement. This study presents a novel methodological protocol used in the co-development of an analog serious game for fall prevention in older adults. The objective was to validate a comprehensive co-design framework that integrates multidisciplinary stakeholder insights with end-user creativity through a sequential, participatory methodology, ensuring both clinical fidelity and high playability.
Memórias do futuro - um diálogo com o passado sustentável
Publication . Lima, Miguel Carlos; Tavares, Mirian; Teixeira, Luís
O projeto “Memórias do Futuro” propõe uma intervenção artística no Sanatório de Mont’alto (Valongo, Portugal), um espaço de ruína arquitetónica e memória cultural. Utilizando fotografias digitais do local, processadas através de inteligência artificial (IA) generativa, foram criados catorze vídeos curtos que reimaginam o edifício abandonado como um cenário revitalizado por princípios de sustentabilidade ecológica. A figura de um boneco Panda, integrada nas imagens, funciona como um agente narrativo que simboliza o cuidado ambiental. A obra manifesta-se num artefacto interativo para tablet e num filme não interativo. Este artigo detalha o enquadramento histórico do sanatório e a metodologia de curadoria humano-máquina do projeto, analisando a obra no quadro teórico da pós-fotografia e do património digital. A experiência da sua exposição in situ é discutida à luz da teoria da Interação Humano-Computador (HCI) e da crise da narração de Walter Benjamin. Adicionalmente, desenvolve uma discussão crítica sobre as implicações desta práxis artística, analisando o deslocamento do conceito de “aura” para o prompt na era da reprodução por IA e confrontando a temática ecológica do projeto com a pegada ambiental da própria tecnologia utilizada (o paradoxo da “Red AI” vs. “Green AI”), estabelecendo um diálogo entre a criação artística e os paradoxos da sustentabilidade digital.
Piecewise rational affine maps, multidimensional generalized shifts, and computation over the real numbers
Publication . Graça, Daniel
In this paper we study the computational power of certain classes of dynamical systems defined by the iteration of piecewise rational affine maps on the compact set [0, 1] n as a model of computation over the real numbers. To achieve this aim we use symbolic dynamics to study the dynamics of this class of piecewise rational affine maps and in the process introduce multidimensional generalized shifts, which are an extension of the generalized shift of Moore to higher dimensional spaces. We show that multidimensional generalized shifts are not equivalent (conjugate) to (one-dimensional) generalized shifts. We then establish that computable analysis, which allows to extend computability based on Turing machines to real numbers, is computationally equivalent to multidimensional generalized shifts, both at a computability and at a computational complexity (polynomial time) level. This implies that a certain class of dynamical systems defined by the iteration of rational piecewise affine maps on the unit ball can thus compute any function computable over the real numbers in the computable analysis sense. These results highlight that several distinct models of computation over the real numbers, such as computable analysis, Claude Shannon’s General Purpose Analog Computer, certain classes of piecewise rational affine maps, and the generalized shift, are all computationally equivalent.
It takes a village: how plant-associated bacterial communities socialise to shape plant growth and health
Publication . Escudero-Martínez, Carmen; Tkacz, Andrzej; Albareda Contreras, Marta; Sánchez-Cañizares, Carmen; Rachel Wheatley
Plants outsource many functions to an associated microbiome, an ‘outside gut’ composed of socially interacting bacterial communities that support plant growth and health. These dynamic and diverse microbiomes span different plant microenvironments and form complex networks shaped by the environmental context and the plant’s genetics. While some microbes cause disease, many others contribute to essential functions, influencing plant fitness, survival, and ultimately soil health. Although the host genetics and abiotic factors structure these communities, the functional diversity and ecological roles of plant-associated bacteria are ultimately shaped by microbe–microbe interactions. These interactions also play a critical role in the successful colonisation of plant tissues. Beneficial members of these communities enhance plant nutrient uptake, modulate phytohormones to shape root architecture, or prime plant systemic immunity to repel pathogens. Deciphering how plant-associated bacterial communities assemble and interact, both with their host and with one another, is essential for uncovering the mechanisms that underpin bacterial social behaviours within the plant holobiont, such as quorum sensing, metabolite exchange, and contact-dependent interactions. Here we review several recent publications that shed new light on the social lives of plant-associated bacteria, with a particular focus on their competition mechanisms and strategies for colonisation and establishment. In this context, we highlight how the rational design of plant bioinoculants based on microbial consortia represents a powerful strategy for promoting sustainable agriculture in a rapidly changing environment.