FEM applied to building physics: modeling solar radiation and heat transfer of PCM enhanced test cells

In passive solar buildings, energy can be stored using either sensible heat materials or latent heat materials. Phase change materials (PCM) can contribute to temperature control in passive solar buildings when melting occurs near to comfort temperature required for building’s interior spaces. The use of finite element method (FEM) as a numerical methodology for solving the thermal problem associated with heat transfer in current building materials and PCMs make sense, as it is a well-known technique, generalized and dominated, however, still little applied to the domain of building physics. In this work, a solar model was developed and applied in order to simulate numerically the effect of solar radiation incidence on each face of the test cells (with different solar exposures) without neglecting the main objective of the recommended numerical simulation: the study of the action of PCM. During the experimental campaign, two test cells with distinct inner layers were used to evaluate the effect of solar radiation: (i) REFM test cell (without PCM) with a reference mortar; (ii) PCMM test cell (with PCM) with a PCM mortar. The temperatures monitored inside the REFM and PCMM test cells were compared with the values resulting from the numerical simulation, using FEM with 3D discretization and the explicit modeling of the solar radiation, and the obtained results revealed a significant coherence of values

Dynamic FE model updating using particle swarm optimization method: A methodology to design critical mechanical composite structures

To increase the performance of an industrial cutting machine, this work studied the possibility of replacing its current main steel gantry by a Carbon Fibre Reinforced Polymer (CFRP) composite solution. This component strongly influences the most relevant characteristics of the equipment, namely accuracy and maxima allowed accelerations. The flexibility of composites in terms of number, thickness and orientation of layers and the challenging trade-offs between weight and stiffness motivated the development of an optimisation process. The Particle Swarm Optimisation method (PSO) was used to develop a solution able to ensure higher accelerations and the required accuracy of the equipment, by optimizing continuously the FE model algorithm input and output assessment and updating it. The process resulted in a near optimal solution allowing a 43% weight reduction and an increase of the maximum allowed acceleration in 25%, while ensuring the same accuracy.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020 and the scholarship SFRH/BD/51106/2010

Litoestratigrafía del “Dominio Esquisto-Grauváquico” en Portugal: una reevaluación

A synthesis of the knowledge of the Schist-Greywacke Domain (SGD) in Portugal is here presented. Until recently, this sequence assumed the designation of Dúrico-Beirão Supergroup composed by the Douro Group (DG) and the Beiras Group (BG). The DG is considered of Neoproterozoic – Cambrian age and the BG is of Neoproterozoic age. The identification and mapping in the BG of an unconformity as the Cadomian unconformity identified in Spain, which splits the Neoproterozoic in “lower Alcudian” and “upper Alcudian”, is a turning point for the understanding and establishment of consistent stratigraphic sequences that now compose the Fróia and the Lousã groups assembled in the Beiras Supergroup. These new groups are correlated with the Neoproterozoic sequences currently recognized in Spain: the Lousã group is equivalent to the Ibor Group (upper Alcudian) and the Fróia Group is equivalent pro parte, to the Domo Extremeño Supergroup.  En este trabajo se presenta una síntesis del conocimiento actual del Dominio del Complejo Esquisto-Grauváquico en Portugal. Hasta al presente esta secuencia ha sido designada como Supergrupo Dúrico-Beirão, compuesto por el Grupo Douro (GD) y por el Grupo Beiras (GB). El GD se consideraba de edad Ediacárico superior – Cámbrico inferior y el GB era atribuido al Neoproterozoico. La identificación y cartografía en el GB de una discordancia correlacionable con la del Cadomiense identificada en España, que divide el Neoproterozoico en "Alcudiense inferior" y "Alcudiense superior", es un punto de inflexión para la comprensión y el establecimiento de secuencias estratigráficas consistentes, que ahora componen los grupos Fróia y Lousã reunidos en el Supergrupo Beiras. Estos nuevos grupos se correlacionan con las secuencias neoproterozoicas actualmente reconocidas en España: el Grupo Lousã es equivalente al Grupo Ibor (Alcudiense Superior) y el Grupo Fróia es equivalente, pro parte, al Supergrupo Domo Extremeño

Litoestratigrafía del “Dominio Esquisto-Grauváquico” en Portugal: una reevaluación

[Abstract] A synthesis of the knowledge of the Schist-Greywacke Domain (SGD) in Portugal is here presented. Until recently, this sequence assumed the designation of Dúrico-Beirão Supergroup composed by the Douro Group (DG) and the Beiras Group (BG). The DG is considered of Neoproterozoic – Cambrian age and the BG is of Neoproterozoic age. The identification and mapping in the BG of an unconformity as the Cadomian unconformity identified in Spain, which splits the Neoproterozoic in “lower Alcudian” and “upper Alcudian”, is a turning point for the understanding and establishment of consistent stratigraphic sequences that now compose the Fróia and the Lousã groups assembled in the Beiras Supergroup. These new groups are correlated with the Neoproterozoic sequences currently recognized in Spain: the Lousã group is equivalent to the Ibor Group (upper Alcudian) and the Fróia Group is equivalent pro parte, to the Domo Extremeño Supergroup.[Resumen] En este trabajo se presenta una síntesis del conocimiento actual del Dominio del Complejo Esquisto-Grauváquico en Portugal. Hasta al presente esta secuencia ha sido designada como Supergrupo Dúrico-Beirão, compuesto por el Grupo Douro (GD) y por el Grupo Beiras (GB). El GD se consideraba de edad Ediacárico superior – Cámbrico inferior y el GB era atribuido al Neoproterozoico. La identificación y cartografía en el GB de una discordancia correlacionable con la del Cadomiense identificada en España, que divide el Neoproterozoico en "Alcudiense inferior" y "Alcudiense superior", es un punto de inflexión para la comprensión y el establecimiento de secuencias estratigráficas consistentes, que ahora componen los grupos Fróia y Lousã reunidos en el Supergrupo Beiras. Estos nuevos grupos se correlacionan con las secuencias neoproterozoicas actualmente reconocidas en España: el Grupo Lousã es equivalente al Grupo Ibor (Alcudiense Superior) y el Grupo Fróia es equivalente, pro parte, al Supergrupo Domo Extremeño

Estimation of the specific enthalpy–temperature functions for plastering mortars containing hybrid mixes of phase change materials

The use of phase change materials (PCMs) for the building sector is increasingly attracting attention from researchers and practitioners. Several research studies forwarded the possibility of incorporating microencapsulated PCM in plastering mortars for building facades, in pursuit of increased energy efficiency associated with the heat storage capacity of PCM. However, most of these studies are centred in the use of a single type of PCM, which is bound to be more adequate for a given season of the year (e.g. winter or summer) than for all the seasons. The study proposed in this work regards the evaluation of the possibility of using more than one kind of PCM, with distinct melting ranges, here termed as hybrid PCMs, in plastering mortars, to achieve adequately advantageous performance in all seasons of the year. To characterize the PCM, the specific enthalpy and phase change temperature should be adequately measured. The main purpose of this study was to show the conceptual feasibility of combining PCMs in mortars and to evaluate the behaviour of the resulting mortars with differential scanning calorimeter. The results showed that the behaviour of the mortar that contains more than one type of PCM can be predicted through the superposition of effects of the independent PCMs and no interaction occurs between them. The knowledge obtained from the experimental testing established bases for a framework of numerical simulation of real-scale applications, which can be used to ascertain the feasibility of the hybrid PCM concept for decreases in energy consumption of heating/cooling demands in the buildings.Fundação para a Ciência e a Tecnologia (FCT

A Multicenter, Non-Interventional Study to Evaluate the Disease Activity in Multiple Sclerosis after Withdrawal of Natalizumab in Portugal

Objectives: Natalizumab (NTZ) is very effective for treatment of relapsing-remitting multiple sclerosis (RRMS), its use is mainly limited by safety issues. Discontinuation of NTZ is associated with recurrence of disease activity (reactivation and rebound). The best strategy for subsequent therapy and the predictive factors for recurrence in such patients are areas of active research. We aimed to evaluate predictors of reactivation in a multicentric study. Patients and methods: Multicentric retrospective observational study in five portuguese MS referral centers. Demographic, clinical and imagiological data were collected in the year prior, during and in the year following NTZ discontinuation. Predictors of reactivation and rebound after NTZ suspension were studied using a multivariate Cox model. Results: Sixty-nine patients were included. They were mainly non-naïve patients (97%), with a mean age of 29.1 ± 8.3 years at diagnosis, and a mean age of 37.2 ± 10.3 years at NTZ initiation. The mean annualized relapse rate (ARR) previous, during and after NTZ was 1.6 ± 1.2, 0.2 ± 0.5 and 0.6 ± 1.0, respectively. The median EDSS before, during and after NTZ was 3.5 (IQR 3.3), 3.5 (IQR 3.5) and 4.0 (IQR 3.8), respectively. The median number of infusions was 26.0 (IQR 12.5) and the main reason to NTZ discontinuation was progressive multifocal leukoencephalopathy (PML) risk (70%). After NTZ suspension, reactivation was observed in 25 (36%) patients after a median time of 20.0 (IQR 29.0) weeks. Reactivation predictors in our sample included NTZ suspension for reasons other than PML (adjusted HR = 0.228, 95% CI [0.084- 0.616], p = 0.004), ARR before NTZ (adjusted HR = 1.914 95% [CI 1.330-2.754], p < 0.001) and a longer disease duration at time of NTZ initiation (adjusted HR = 1.154, 95% CI [1.020-1.306], p = 0.023). Rebound occurred in 5 (7%) patients after a median time of 20 (IQR 34.5) weeks. Conclusion: Significant predictors of disease reactivation in our cohort were discontinuation of NTZ for reasons other than PML risk, higher disease activity before NTZ treatment, and longer disease duration. Our study provides valuable data of portuguese patients after NTZ withdrawal.info:eu-repo/semantics/publishedVersio

Complicações agudas da diabetes mellitus

Estudaram-se retrospectivamente 83 processos clínicos, correspondentes à totalidade dos doentes internados, no Serviço de Medicina, por complicações agudas da Diabetes Mellitus, num periodo compreendido entre os anos de 1986 e 1993, no total de oito anos. Foram analizadas algumas variaveis clínicas (idade, tipo de complicação e frequência, forma de apresentação, causa desencadeante, características bioquímicas e actuação terapêutica) e tratadas estatísticamente, comparando se as populações pelo método de Tde Student, não emparelhado. Os resul tados obtidos, foram comparados com os referidos na Literatura da Especialidade, permitindo apurar algumas conclusões significativas.A retrospective study was made of 83 diabetic patients admitted to the Department of Internal Medicine between January 1986 and December 1993, with acute intercurrence of the disease. The authors considered some clinical features (age, type and frequency of complication, form of presentation, causal aetiology, laboratory findings and therapeutic options). Statistical relationships between different populations were made using the unpaired Student’s T. method. Results were compared with those in the literature, leading to some significant conclusions.info:eu-repo/semantics/publishedVersio

Antioxidants in Portuguese wild mushrooms: a phenolic profile

The implication of oxidative and nitrosative stress in the etiology and progression of several acute and chronic clinical disorders such as cancer, cardiovascular and neurodegenerative diseases, has led to the suggestion that natural antioxidants can have health benefits as prophylactic agents (1). In this perspective, the presence of mushrooms in our diet which contain significant amounts of bioactive phytochemicals, may provide desirable health benefits, beyond basic nutrition. Many studies have concluded that mushrooms possess potent antioxidant properties related to phenolic compounds. In the present work, the analysis of phenolic compounds in Portuguese wild mushroom species was carried out by high-performance liquid chromatography coupled to photodiode array detector (HPLC-DAD). Four phenolic acids (protocatechuic, p-hydroxybenzoic, p-coumaric and cinnamic acids) were found and quantified. Fistulina hepatica showed the highest concentration in phenolic acids (111.72 mg/Kg, dry matter) due to the significant contribution of protocatechuic (67.62 mg/Kg) and p-hydroxybenzoic (41.92 mg/kg) acids. Results will be discussed highlighting the potential prophylactic capacity of these natural antioxidants

Synthesis, structural and magnetic characterization of lead-metaniobate/cobalt-ferrite nanocomposite films deposited by pulsed laser ablation

Detailed structural, microstructural and magnetic measurements were performed on (PbNb2O6)(1-x) -(CoFe2O4) (x) nanocomposite thin films deposited by laser ablation on Si(001)\Pt substrates, with different cobalt ferrite concentrations. The tuning of the lead concentration, due to the lead volatility, was found to be particularly important in order to obtain the orthorhombic (ferroelectric) lead niobate phase. The lattice parameter of CoFe2O4 was below the bulk value, indicating the presence of compressive strains on this phase. A magnetic anisotropy was observed, which favored the orientation of the magnetization in the direction perpendicular to the plane of the films, for cobalt ferrite concentrations 40-50 %. The shape, stress and magnetocrystalline anisotropy fields on the composites were calculated and compared. It was found that the perpendicular magnetic anisotropy was induced by the presence of strain on the ferrite phase in the films.- This work has been supported by Fundacao para a Ciencia e Tecnologia (FCT) and FEDER, through the projects POCI/CTM/60181/2004 and PTDC/CTM/099415/2008. J. Barbosa and I. T. Gomes gratefully acknowledge Ph.D. grants from Fundacao para a Ciencia e Tecnologia (SFRH/BD/41913/2007 and SFRH/BD/36348/2007, respectively).info:eu-repo/semantics/publishedVersio

The national inventory of geological heritage: methodological approach and results

A existência de um inventário nacional de património geológico é fundamental para se poderem implementar estratégias de geoconservação. Este trabalho apresenta a metodologia usada no desenvolvimento do mais completo inventário de geossítios, realizado até ao momento em Portugal, assim como os principais resultados obtidos. O inventário vai integrar o Sistema de Informação do Património Natural e o Cadastro Nacional dos Valores Naturais Classificados, ambos geridos pelo Instituto de Conservação da Natureza e da Biodiversidade.The existence of a national inventory of the geological heritage is of paramount importance for the implementation of a geoconservation strategy. This paper presents the methodological approach used to produce the most complete geosites inventory in Portugal, so far, and the obtained results. This inventory will be uploaded into the National Database of Natural Heritage managed by the Portuguese authority for nature conservation.Este trabalho é apoiado pela Fundação para a Ciência e a Tecnologia, através do financiamento plurianual do CGUP e do projecto de investigação “Identificação, caracterização e conservação do património geológico: uma estratégia de geoconservação para Portugal” (PTDC/CTE-GEX/64966/2006).info:eu-repo/semantics/publishedVersio