Web-based access control system

This article describes a web-based system to control and manage the access to the ESTCB, which it is under development as a student’s final project. Beyond an important pedagogical and technological value, we believe that this work is an important step towards offering strong and efficient security management for access control systems. We make use of standard technologies in use on the Web, to make an effective campus-wide security system. The system management and configuration, the consultation of access information for schedules, users, spaces, among others, will be carried out through the Internet. The proposed model is based on the use of two data nets: a CAN field bus to which are connected magnetic cards readers, door locks and sensors of each access place and the Ethernet that establishes connection between different CAN field bus and servers, which contain information about users and access rules

The Sociopolitical Conflict In Hydroelectric Enterprises

Electrical energy is the basis of the lifestyle of contemporary society, whose main source in Brazil, is the dam, requiring the construction of major infrastructure projects. These projects drive contradictory social and political processes. In these processes, we glimpse the conflict between the Specific Purpose Entities (SPE), proponents of hydropower, and the Touched, representative parts of local populations forcibly displaced as a result of these works Movement of Affected by Dams. Having locus as the basin of Uruguay, southern Brazil, this article discusses the conflict through a "loop analysis" consists of hydropower and resettlement. We sought to understand the frequency and the motivations of those affected to participate politically in later demonstrations against their relocation hydropower. Therefore, we use a methodology that links qualitative and quantitative tools based on empirical research. The study enables us to understand that the primary motivator for participation of those affected in later for their resettlement mobilizations is human solidarity.192456

Experimental assessment of the performance of two marine coatings to curb biofilm formation of microfoulers

Biofilms formed on submerged marine surfaces play a critical role in the fouling process, causing increased fuel consumption, corrosion, and high maintenance costs. Thus, marine biofouling is a major issue and motivates the development of antifouling coatings. In this study, the performance of two commercial marine coatings, a foul-release silicone-based paint (SilRef) and an epoxy resin (EpoRef), was evaluated regarding their abilities to prevent biofilm formation by Cyanobium sp. and Pseudoalteromonas tunicata (common microfoulers). Biofilms were developed under defined hydrodynamic conditions to simulate marine settings, and the number of biofilm cells, wet weight, and thickness were monitored for 7 weeks. The biofilm structure was analyzed by confocal laser scanning microscopy (CLSM) at the end-point. Results demonstrated that EpoRef surfaces were effective in inhibiting biofilm formation at initial stages (until day 28), while SilRef surfaces showed high efficacy in decreasing biofilm formation during maturation (from day 35 onwards). Wet weight and thickness analysis, as well as CLSM data, indicate that SilRef surfaces were less prone to biofilm formation than EpoRef surfaces. Furthermore, the efficacy of SilRef surfaces may be dependent on the fouling microorganism, while the performance of EpoRef was strongly influenced by a combined effect of surface and microorganism.This research was funded by Base Funding - UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology, and Energy - LEPABE - funded by national funds through the FCT/MCTES (PIDDAC), “CVMAR+i - Industrial Innovation and Marine Biotechnology Valorization” project, funded by INTERREG V Espanha Portugal (POCTEP) (0302_CVMAR_I_1_P), and UIDB/04423/2020 and UIDP/04423/2020 (CIIMAR). The research work was also supported by UIDB/04046/2020 and UIDP/04046/2020 research units grants, Portugal (to BioISI). R.T.-S. thanks the receipt of a junior researcher fellowship from the Project PTDC/BII-BIO/29589/2017 POCI-01-0145-FEDER-029589 funded by FEDER funds through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES. L.C.G. thanks the Portuguese Foundation for Science and Technology (FCT) for the financial support of her work contract through the Scientific Employment Stimulus-Individual Call-[CEECIND/01700/2017]. Atomic force microscopy technique was performed at the Biointerface and Nanotechnology i3S Scientific Platform with the assistance of Manuela Brás

Stability and electrochemical performance of nanostructured La2CuO4þd cathodes

La2CuO4þd cathode layers are prepared by spray-pyrolysis deposition and their structural, microstructural and electrical properties are compared with those of submicrometric powders obtained from freeze-dried precursors. In order to improve the cathode performance, three different electrode architectures have been proposed: (i) powder cathodes obtained by conventional screen-printing and sintering, and cathodes deposited by spray-pyrolysis on: (ii) as-prepared electrolyte surfaces and (iii) porous electrolyte backbones. The cathode activity for the oxygen reduction reaction has been investigated as a function of the microstructure and the sintering temperature. The microstructural optimization of the cathodes and the low fabrication temperature minimize the instability problems between the electrolyte and the cathode materials, leading to polarization resistances as low as 0.14 U cm2 at 600 C.MINECO (Ministerio de Economía y Competitividad), MAT2016-77648-R y EC2014-53906-

Durability and performance of CGO barriers and LSCF cathode deposited by spray-pyrolysis

Ce0.9Gd0.1O1.95 (CGO) protective layers are prepared by two different methods to prevent the reaction between the Zr0.84Y0.16O1.92 (YSZ) electrolyte and the La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode. In the first method, the CGO layers are deposited by an airbrushing technique from an ink containing CGO particles without and with cobalt as sintering aids. The second strategy consists in preparing both a dense CGO barrier layer and a porous LSCF cathode by spray-pyrolysis deposition, in order to further reduce the fabrication temperature and minimize the reaction between the cell components. The samples prepared by spray-pyrolysis exhibit better performance and durability than those obtained by conventional sintering methods. The results suggest that the interfacial reactivity between YSZ and LSCF as well as the Sr-enrichment at the cathode surface can be avoided by using low-temperature fabrication methods and by operating at temperatures lower than 650 °C.Ministerio de Ciencia e Innovación, EC2014-53906-R y MAT2016-77648-

Highly efficient La0.8Sr0.2MnO3-δ - Ce0.9Gd0.1O1.95 nanocomposite cathodes for solid oxide fuel cells

La0.8Sr0.2MnO3-δ-Ce0.9Gd0.1O1.95 (LSM-CGO) nanostructured cathodes are successfully prepared in a single process by a chemical spray-pyrolysis deposition method. The cathode is composed of nanometric particles of approximately 15 nm of diameter, providing high triple-phase boundary sites for the oxygen reduction reactions. A low polarization resistance of 0.046 Ω cm2 is obtained at 700 °C, which is comparable to the most efficient cobaltite-based perovskite cathodes. A NiO-YSZ anode supported fuel cell with the nanostructured cathode generates a power output of 1.4 W cm−2 at 800 °C, significantly higher than 0.75 W cm−2 for a cell with conventional LSM-CGO cathode. The results suggest that this is a promising strategy to achieve high efficiency electrodes for Solid Oxide Fuel Cells in a single preparation step, simplifying notably the fabrication process compared to traditional methods.Ministerio de Ciencia e Innovació

Effect of Zn addition on the structure and electrochemical properties of codoped BaCe0.6Zr0.2Ln0.2O3-δ (Ln=Y, Gd, Yb) proton conductors

In this work, BaCe0.6Zr0.2Y0.2-xYbxO3-δ and BaCe0.6Zr0.2Gd0.2-xYbxO3-δ (x=0–0.20), proton conducting materials are prepared by the freeze-drying precursor method. The sintering conditions were optimized by adding Zn (NO3)2·6H2O as sintering additive. The materials are thoroughly characterized by different structural and microstructural techniques, including X-ray diffraction, scanning and transmission electron microscopy, and thermogravimetric-differential thermal analysis. The addition of Zn favours the phase formation and densification at lower sintering temperatures; however, it leads to the segregation of a Zn-rich secondary phase, with general formula BaLn2ZnO5 (Ln˭Y, Gd and Yb), which is identified and quantified for the first time. All samples with Zn as sintering aid exhibit cubic structure; however, the samples without Zn crystallize with orthorhombic or cubic structure, depending on the composition and thermal treatment. The electrical properties are studied by impedance spectroscopy. A deep analysis of the bulk and grain boundary contributions to the conductivity has revealed that the bulk conductivity remains almost unchanged along both series over Yb-doping; however, the grain boundary resistance decreases. The highest conductivity values are found for the intermediate members of both series, BaCe0.6Zr0.2Y0.1Yb0.1O3-δ and BaCe0.6Zr0.2Gd0.1Yb1O3-δ, with 33 and 28 mS cm−1 at 750 °C, respectively.Ministerio de Economía y Competitividad), MAT2016-77648-

Reionization: Characteristic Scales, Topology and Observability

Recently the numerical simulations of the process of reionization of the universe at z>6 have made a qualitative leap forward, reaching sufficient sizes and dynamic range to determine the characteristic scales of this process. This allowed making the first realistic predictions for a variety of observational signatures. We discuss recent results from large-scale radiative transfer and structure formation simulations on the observability of high-redshift Ly-alpha sources. We also briefly discuss the dependence of the characteristic scales and topology of the ionized and neutral patches on the reionization parameters.Comment: 4 pages, 5 figures (4 in color), to appear in Astronomy and Space Science special issue "Space Astronomy: The UV window to the Universe", proceedings of 1st NUVA Conference ``Space Astronomy: The UV window to the Universe'' in El Escorial (Spain