RCIPL
Repositório Institucional do Politécnico de Lisboa
Entradas recentes
Implementing composting and awareness campaigns in a higher education institution to promote circularity
Publication . Craveiro, Ana Lúcia; Santos, Maria Teresa; Rodrigues, Alexandra
Sustainable waste management is essential for environmental protection and climate change mitigation. In mainland Portugal, 59% of municipal waste was sent to landfills in 2023, while only 8% underwent organic valorization. Domestic composting offers low-cost, local solutions to reduce landfill dependency and promote a circular economy. When produced with quality, compost can be used in parks and gardens, improving soil structure, supplying nutrients for plants, and promoting water retention. This study describes the implementation of a composting program at a Higher Education Institution in Lisbon, focusing on community engagement, awareness-raising actions, process monitoring, and challenges faced. The training sessions increased the participants' knowledge, who reported personal constraints in urban areas, such as limited space and slow composting rates. The results from the composting assays showed that the temperature and the pH followed the expected patterns, with the pH ranging from 4 to 9. Although the composting process progressed satisfactorily, the maximum temperature reached was approximately 45 degrees C, a value that can occur in home composting systems. The compost analysis showed a mature compost with pH values around 8, a dark color, and an earthy smell, proper for use. Nonetheless, challenges remain, including contaminants found in some composters and the need for increased community participation and awareness to fully engage all stakeholders.
One-loop pseudoscalar mass in a 2HDM with a Z3 symmetry
Publication . Ferreira, Pedro; Pinto, Tomás F.
A two-Higgs doublet model with a discrete Z3 symmetry acquires, in its scalar and gauge sectors, an accidental continuous U(1) symmetry. One therefore finds, after spontaneous symmetry breaking of those symmetries, that a massless pseudoscalar arises, as expected by Goldstone's theorem. In the fermion sector, however, it is possible to obtain Yukawa matrix textures which distinguish between the Z3 and U(1) symmetries, so one expects loop corrections to originate a non-zero pseudoscalar mass for the Z3 case. We perform an explicit calculation that shows that at one-loop the pseudoscalar remains massless for all but one tested Z3 Yukawa matrices. The pseudoscalar mass thus found is highly suppressed by the hierarchy of fermion masses.
Finite element analysis of non-uniform functionally graded multi-cracked Timoshenko beams using an equilibrium-based formulation
Publication . Freixial Argente dos Santos, Hugo Alexandre; Silberschmidt, V. V.
A novel finite element formulation is introduced for the static analysis of non-uniform functionally graded multi-cracked Timoshenko beams with small deformations. The cracks, assumed to remain open, are modelled using the so-called discrete spring approach, in which Dirac delta generalized functions are introduced into the bending flexibility of the beams. The formulation is derived on the basis of a complementary variational approach that involves only the elements' shear forces and bending moments as the fundamental unknown fields. The corresponding element flexibility matrix is obtained in closed-form, with the crack contributions explicitly separated from the standard bending and shear flexibility terms. The numerical solutions produced by the formulation are strictly equilibrated, i.e., they satisfy all equilibrium conditions of the associated boundary-value problem in strong form. The effectiveness and accuracy of the formulation are numerically assessed through its application to several benchmark problems. The obtained results are analysed and compared, where possible, to exact (or reference) solutions and solutions given by the standard displacement-based finite element formulation, clearly illustrating the capability of the formulation to deliver highly accurate results for both thin and thick beams, even on meshes with only a few degrees-of-freedom.
Ghostance: on the materiality feeling of dancing bodies in virtual reality
Publication . Pinto Coelho, Silvia; De Lima, Cecília; Antunes, Rui Filipe
ABSTRACT - The GhostDance research project explores the changes in dancers' body perception when interacting with virtual bodies. Virtual reality's volatile and insubstantial nature, with its liquid architectures (Novak, 1992) and massless, weightless and fluid bodies, can be seen as inherently ghostly. The study aims to investigate how the presence and interaction with a body are influenced by the existence of a spectral dimension, be it our own body or that of another person or virtual entity. The research includes a live performance where two dancers contrast dance between physical and virtual reality partners, creating a phantasmagorical dialogue between human and virtual bodies. The study looks at changes in sensory-motor perception, kinesphere awareness, tactile experience, and the perception of weight and effort of dancers performing with virtual characters. It draws upon first-hand accounts from dancers to shed light
on the complex interaction between physical and virtual elements in the dancers’ experience. The study’s findings pave the way for reflections onthe implications of these interactions
Plane frame structures: optimization and design solutions clustering
Publication . Gaspar, Joana S. D.; Loja, Amélia; Barbosa, Joaquim
This work aims to constitute a framework dataflow based on the prediction, optimization, and characterization of optimal solutions. To this purpose, a metaheuristic optimization method is used to obtain the optimal design solutions for discrete plane frame structures considering as objective function the minimization of their maximum resultant displacement, subjected to side and behavioral constraints. The design variables that lead to the optimal solutions are constituted into datasets which are subsequently submitted to a clustering analysis. The results obtained provide pertinent insights about the optimal solutions clusters’ ranges, giving effective support to a specific solution selection.