Multimedia Technology and 3D Environments used in the Preservation and Dissemination of Portuguese Cultural Heritage

Cultural heritage is an extremely valuable set of materiality, traditions and knowledge from the Past that should be used to better understand the Past itself. However, even nowadays there are still some difficulties to manage, preserve and disseminate cultural heritage sites. The usage of multimedia technology and 3D environments in cultural heritage has reduced these difficulties; nonetheless, there are still some remaining problems. In the last years, some multimedia technology and 3D environments have been applied to the cultural heritage in Portugal. A few of them are used for scientific research purposes and others are used for dissemination purposes. In this article, the authors will refer to some representative Portuguese case studies using Virtual Environments to maintain, preserve and promote Cultural Heritage. A critical reading of these projects will be made in order to stress out their success and to point out their weaknesses and limitations

Enrollment time as a requirement for biometric hand recognition systems

Biometric systems are increasingly being used as a means for authentication to provide system security in modern technologies. The performance of a biometric system depends on the accuracy, the processing speed, the template size, and the time necessary for enrollment. While much research has focused on the first three factors, enrollment time has not received as much attention. In this work, we present the findings of our research focused upon studying user’s behavior when enrolling in a biometric system. Specifically, we collected information about the user’s availability for enrollment in respect to the hand recognition systems (e.g., hand geometry, palm geometry or any other requiring positioning the hand on an optical scanner). A sample of 19 participants, chosen randomly apart their age, gender, profession and nationality, were used as test subjects in an experiment to study the patience of users enrolling in a biometric hand recognition system.by FCT – Fundação para a Ciência e Tecnologia within the Project Scope UID/CEC/00319/20

Macro-, meso- and microstructural characterization of metallic lattice structures manufactured by additive manufacturing assisted investment casting

Cellular materials are recognized for their high specific mechanical properties, making them desirable in ultra-lightweight applications. Periodic lattices have tunable properties and may be manufactured by metallic additive manufacturing (AM) techniques. However, AM can lead to issues with un-melted powder, macro/micro porosity, dimensional control and heterogeneous microstructures. This study overcomes these problems through a novel technique, combining additive manufacturing and investment casting to produce detailed investment cast lattice structures. Fused filament fabrication is used to fabricate a pattern used as the mold for the investment casting of aluminium A356 alloy into high-conformity thin-ribbed (~ 0.6 mm thickness) scaffolds. X-ray micro-computed tomography (CT) is used to characterize macro- and meso-scale defects. Optical and scanning electron (SEM) microscopies are used to characterize the microstructure of the cast structures. Slight dimensional (macroscale) variations originate from the 3D printing of the pattern. At the mesoscale, the casting process introduces very fine (~ 3 µm) porosity, along with small numbers of (~ 25 µm) gas entrapment defects in the horizontal struts. At a microstructural level, both the (~ 70 μm) globular/dendritic grains and secondary phases show no significant variations across the lattices. This method is a promising alternative means for producing highly detailed non-stochastic metallic cellular lattices and offers scope for further improvement through refinement of filament fabrication.This work was supported by Portuguese FCT, under the reference project UIDB/04436/2020. We are grateful to the funding from the European Research Council through the ERC grant CORREL-CT, number 695638 to enable VHC to visit the Henry Royce Institute to undertake the X-ray CT studies. Tis work was supported by the Henry Royce Institute for Advanced Materials, funded through EPSRC grants EP/R00661X/1, EP/S019367/1, EP/P025021/1 and EP/P025498/1 and the Henry Moseley X-ray Imaging Facility funded by EP/T02593X/1

Dynamic piezoelectric stimulation enhances osteogenic differentiation of human adipose stem cells

This work reports on the influence of the substrate polarization of electroactive β-PVDF on human adipose stem cells (hASCs) differentiation under static and dynamic conditions. hASCs were cultured on different β-PVDF surfaces (non-poled and “poled -”) adsorbed with fibronectin and osteogenic differentiation was determined using a quantitative alkaline phosphatase assay. “Poled -” β-PVDF samples promote higher osteogenic differentiation, which is even higher under dynamic conditions. It is thus demonstrated that electroactive membranes can provide the necessary electromechanical stimuli for the differentiation of specific cells and therefore will support the design of suitable tissue engineering strategies, such as bone tissue engineering.This work is funded by FEDER funds through the "Programa Operacional Fatores de Competitividade – COMPETE" and by national funds arranged by FCT- Fundação para a Ciência e a Tecnologia, project references PTDC/CTM-NAN/112574/2009 and PEST-C/FIS/UI607/2014. The authors also thank funding from Matepro –Optimizing Materials and Processes”, ref. NORTE-07-0124-FEDER-000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 – O Novo Norte), under the “Quadro de Referência Estratégico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). CR, VS and VC thank the FCT for the SFRH/BPD/90870/2012, SFRH/BPD/64958/2009 and SFRH/BPD/97739/2013 grants, respectively. Academy of Finland is acknowledged for research funding (projects 136288 (VH) and 256931 (JP))

Lusitanian toadfish song reflects male quality

Lusitanian toadfish males that provide parental care rely on acoustic signals (the boatwhistle) to attract females to their nest. We test the hypothesis that male quality, namely male size and condition that are relevant for parental success, is reflected in vocal activity and boatwhistle characteristics and thus advertised to females. We recorded 22 males over a week during the peak of the breeding season. Calling rate and calling effort (percentage of time spent calling) strongly reflected male condition (lipid content of somatic muscles) and to a smaller extent sonic muscle hypertrophy and larger gonads. Males in better condition (increased body lipid and relative higher liver mass) also contracted the sonic muscles at faster rate as shown by the shorter boatwhistle pulse periods. Amplitude modulation reflected the degree of sonic muscle hypertrophy. None of the measured male quality parameters were good predictors of boatwhistle duration and dominant frequency. Altogether this study strongly suggests that Lusitanian toadfish males advertise their quality to females primarily with boatwhistle calling rate and calling effort, which mainly reflect male condition. Because pulse period had low variability, consistent with the existence of a vocal central pattern generator, we suggest that males that sustain sonic muscles contraction at a very fast rate close to their physiological limit may be honestly advertising their quality (condition). Similarly, males that produce boatwhistles with higher amplitude modulation, a feature that seems dependent on sonic muscle hypertrophy, could be more attractive to females.Fundação para a Ciência e Tecnologiainfo:eu-repo/semantics/publishedVersio

Piezoresistive silicon thin film sensor array for biomedical applications

N-type hydrogenated nanocrystalline silicon thin film piezoresistors, with gauge factor −28, were deposited on rugged and flexible polyimide foils by Hot-wire chemical vapor deposition using a tantalum filament heated to 1750 °C. The piezoresistive response under cyclic quasi-static and dynamical (up to 100 Hz) load conditions is reported. Test structures, consisting of microresistors having lateral dimensions in the range from 50 to 100 μm and thickness of 120 nm were defined in an array by reactive ion etching. Metallic pads, forming ohmic contacts to the sensing elements, were defined by a lift-off process. A readout circuit for the array consisting in a mutiplexer on each row and column of the matrix is proposed. The digital data will be processed, interpreted and stored internally by an ultra low-power micro controller, also responsible for the communication of two-way wireless data, e.g. from inside to outside the human body.© 2011 Elsevier B.V. All rights reservedFundação para a Ciência e a Tecnologia (FCT

Experimental and Techno-Economic Study on the Use of Microalgae for Paper Industry Effluents Remediation

Humanity is facing some major global threats, namely lack of environmental sustainability, the energy crisis associated with the unsustainable reliance on fossil fuels, and water scarcity, which will be exacerbated with the rapid growth of urban areas. Researchers have drawn their attention to microalgae, photosynthetic microorganisms known for their environmental applications, such as wastewater remediation and lipids accumulation, to produce third-generation biofuels to solve some of these major issues. Considering this dual role, this study evaluated the potential of the microalga Chlorella vulgaris on nutrient removal from a paper industry effluent and bioenergy production. Firstly, experiments were performed to assess the potential of this microalga to: (i) successfully grow in different concentrations of a paper industry effluent (20% to 100%); and (ii) treat the industrial effluent, reducing phosphorus concentrations to values below the accepted legal limits. Then, a techno-economic assessment was performed to study the viability of a C. vulgaris biorefinery targeting the remediation of a paper industry effluent and bioenergy production. The results have shown that C. vulgaris was able to successfully grow and treat the paper industry effluent. Under these conditions, average biomass productivities determined for this microalga ranged between 15.5 +/- 0.5 and 26 +/- 1 mg dry weight (DW) L-1 d(-1), with maximum biomass concentrations reaching values between 337 +/- 9 and 495 +/- 25 mg DW L-1 d(-1). Moreover, final phosphorus concentrations ranged between 0.12 +/- 0.01 and 0.5 +/- 0.3 mg P L-1, values below the legal limits imposed by the Portuguese Environment Agency on the paper industry. Regarding the proposal of a microalgal biorefinery for the bioremediation of paper industry effluents with bioenergy production, the techno-economic study demonstrated that six of the seven studied scenarios resulted in an economically-viable infrastructure. The highest net present value (15.4 million euros) and lowest discounted payback period (13 years) were determined for Scenario 3, which assumed a photosynthetic efficiency of 3%, a lipids extraction efficiency of 75%, and an anaerobic digestion efficiency of 45%. Therefore, it was possible to conclude that besides being economically viable, the proposed biorefinery presents several environmental benefits: (i) the remediation of an industrial effluent; (ii) CO2 uptake for microalgal growth, which contributes to a reduction in greenhouse gases emissions; (iii) production of clean and renewable energy; (iv) soil regeneration; and (v) promotion of a circular economy

Degradation of the dielectric and piezoelectric response of b-poly(vinylidene fluoride) after temperature annealing

The effect of annealing temperature and time on the dielectric and piezoelectric response of poly(vinylidene fluoride), PVDF, has been studied. The observed decrease in the value of the dielectric, έ, and piezoelectric, d33, constants is related to depoling of the material and not to variations of the degree of crystallinity or the electroactive β-phase content. In a general way, the dielectric and piezoelectric responses decrease strongly in the first four hours at a given temperature, in particular for temperatures higher that 80 ºC, reaching stable values for longer annealing times. For most applications, the temperature of 100 ºC will set the limit of suitable performance. Nevertheless, the material still retains stable piezoelectric response of ~ 4 pC/N after reaching temperatures of 140 ºC. The mechanisms behind the observed behavior have been discussedFundação para a Ciência e a Tecnologia (FCT) - bolsa PTDC/CTM/73030/2006, NANO/NMed-SD/0156/2007, bolsa SFRH/BPD/63148/200

Influence of ferrite nanoparticle type and content on the crystallization kinetics and electroactive phase nucleation of poly(vinilidene fluoride)

This work reports on the nucleation of the β-phase of poly(vinylidene fluoride), PVDF, by incorporating CoFe2O4 and NiFe2O4 nanoparticles, leading in this way, to the preparation of magnetoelectric composites. The fraction of filler nanoparticles needed to produce the same β- to α-phase ratio in crystallized PVDF is one order of magnitude lower in the Cobalt nanoparticles. The interaction between nanoparticles and PVDF chains induce the all trans conformation in PVDF segments and this structure then propagates in crystal growth. The nucleation kinetics is enhanced by the presence of nanoparticles, as corroborated by the increasing number of spherulites with increasing nanoparticle content and by the variations of the Avrami’s exponent. Further, the decrease of the crystalline fraction of PVDF with increasing nanoparticles content indicates that an important fraction of polymer chains are confined in interphases with the filler particle.Centro de Investigación Principe FelipeInstituto de Salud Carlos III (Ministry of Science and Innovation).FEDER funds through the "Programa Operacional Factores de Competitividade – COMPETE"Fundação para a Ciência e a Tecnologia (FCT) - NANO/NMed-SD/0156/2007, PTDC/CTM/69316/2006, SFRH/BPD/63148/2009Conselleria de Sanidad (Generalitat Valenciana)Spanish Ministry of Education through project No. MAT2010-21611-C03-01, EUI2008-0012

Topologies and operation modes of rail power conditioners in AC traction grids: review and comprehensive comparison

Electric locomotives in AC traction power systems represent a huge single-phase non-linear load and, detrimentally, affect the power quality and the efficiency of the three-phase power grid. Nevertheless, along the last decades, power electronics are being used to mitigate power quality problems in the three-phase power grid. In particular, Rail Power Conditioner (RPC) helps to increase the loading capacity of traction substations and improve the power quality of three-phase power grids. As the main characteristics, an RPC can supply reactive power, suppress current harmonics and overcome currents imbalance of the three-phase power grid. On the other hand, the traction substations may be constituted by different types of power transformers. For instance, single-phase power transformers and open-delta (V/V) power transformers are widely used, while Scott power transformers are less frequently used, since they are more complex and expensive. In this framework, this work presents a review study of RPC topologies, including their operation modes, and a comprehensive comparison between the characteristics of the RPC topologies when using different types of AC traction substations and power transformers. This helps to ensure the correct selection of the RPC topology for a specific application, according to the main structure of the traction substation. Consequently, and based on the established review, it is possible to sort and allocate each RPC topology for limited or wider applications.This work was supported by the Portuguese Foundation of Science and Technology (FCT) (in Portuguese, Fundação para a Ciência e Tecnologia, within the R&D Units Project Scope: UIDB/00319/2020). The first author Mohamed Tanta is supported by FCT Ph.D. grant with a reference PD/BD/127815/2016