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2019
Rovisco, Ana, Rita Branquinho, Jorge Martins, Elvira Fortunato, Rodrigo Martins, and Pedro Barquinha. "{Growth Mechanism of Seed-Layer Free ZnSnO3 Nanowires: Effect of Physical Parameters}." Nanomaterials. 9 (2019): 1002. AbstractWebsite

ZnSnO3 semiconductor nanostructures have several applications as photocatalysis, gas sensors, and energy harvesting. However, due to its multicomponent nature, the synthesis is far more complex than its binary counter parts. The complexity increases even more when aiming for low-cost and low-temperature processes as in hydrothermal methods. Knowing in detail the influence of all the parameters involved in these processes is imperative, in order to properly control the synthesis to achieve the desired final product. Thus, this paper presents a study of the influence of the physical parameters involved in the hydrothermal synthesis of ZnSnO3 nanowires, namely volume, reaction time, and process temperature. Based on this study a growth mechanism for the complex Zn:Sn:O system is proposed. Two zinc precursors, zinc chloride and zinc acetate, were studied, showing that although the growth mechanism is inherent to the material itself, the chemical reactions for different conditions need to be considered.

Clemente, Pedro, Marta Calvache, Paula Antunes, Rui Santos, Jorge Orestes Cerdeira, and Maria João Martins. "Combining social media photographs and species distribution models to map cultural ecosystem services: The case of a Natural Park in Portugal." Ecological Indicators. 96 (2019): 59-68. AbstractWebsite
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Duarte, Susana, Helena Carvalho, and V. Cruz-Machado. "Editorial." International Journal of Advanced Operations Management. 11 (2019): 1-7. Abstract
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Duarte, Susana, and V. Cruz-Machado. "Green and lean supply-chain transformation: a roadmap." Production Planning & Control (2019). Abstract

Green and lean are manufacturing management paradigms that identify new opportunities to improve the business to be more competitive. The purpose of this research is to contribute for the understanding of how to address green–lean approaches in a supply chain. The objective is to provide basic mechanisms to implement an organization’s supplychain based on an integrated green and lean approach. To attain this objective, some relevant initiatives for a green and lean transformation were considered first. Second, a multiple case study was conducted in the automotive industry to test qualitatively the several integrated green and lean initiatives and see how they are being implemented in the real world. Based on the literature review and the case study, an oriented-tool is suggested, which involves a roadmap to achieve a green–lean supply-chain transformation. The proposed roadmap can serve as the basis for further research in green and lean supply chain management, providing insights into the implementation of a green–lean approach.

Gao, Tian, Jingyu Yan, Chang-Cheng Liu, Angelina S. Palma, Zhimou Guo, Min Xiao, Xi Chen, Xinmiao Liang, Wengang Chai, and Hongzhi Cao. "{Chemoenzymatic Synthesis of O-Mannose Glycans Containing Sulfated or Nonsulfated HNK-1 Epitope.}." Journal of the American Chemical Society. 141 (2019): 19351-19359. Abstract

The human natural killer-1 (HNK-1) epitope is a unique sulfated trisaccharide sequence presented on O- and N-glycans of various glycoproteins and on glycolipids. It is overexpressed in the nervous system and plays crucial roles in nerve regeneration, synaptic plasticity, and neuronal diseases. However, the investigation of functional roles of HNK-1 in a more complex glycan context at the molecular level remains a big challenge due to lack of access to related structurally well-defined complex glycans. Herein, we describe a highly efficient chemoenzymatic approach for the first collective synthesis of HNK-1-bearing O-mannose glycans with different branching patterns, and for their nonsulfated counterparts. The successful strategy relies on both chemical glycosylation of a trisaccharide lactone donor for the introduction of sulfated HNK-1 branch and substrate promiscuities of bacterial glycosyltransferases that can tolerate sulfated substrates for enzymatic diversification. Glycan microarray analysis with the resulting complex synthetic glycans demonstrated their recognition by two HNK-1-specific antibodies including anti-HNK-1/N-CAM (CD57) and Cat-315, which provided further evidence for the recognition epitopes of these antibodies and the essential roles of the sulfate group for HNK-1 glycan-antibody recognition.

Vieira, F., B. Sarmento, A. S. Reis-Machado, J. Facão, M. J. Carvalho, MJ Mendes, E. Fortunato, and R. Martins. "{Prediction of sunlight-driven CO2 conversion: Producing methane from photovoltaics, and full system design for single-house application}." Materials Today Energy. 14 (2019). Abstract

CO2 capture and utilization (CCU) technologies are being immensely researched as means to close the anthropogenic carbon cycle. One approach known as artificial photosynthesis uses solar energy from photovoltaics (PV), carbon dioxide and water to generate hydrocarbon fuels, being methane (CH4) a preferential target due to the already in place infrastructures for its storage, distribution and consumption. Here, a model is developed to simulate a direct (1-step) solar methane production approach, which is studied in two scenarios: first, we compare it against a more conventional 2-step methane production route, and second, we apply it to address the energetic needs of concept buildings with usual space and domestic hot water heating requirements. The analysed 2-step process consists in the PV-powered synthesis of an intermediate fuel – syngas – followed by its conversion to CH4 via a Fischer–Tropsch (methanation) process. It was found that the 1-step route could be adequate to a domestic, small scale use, potentially providing energy for a single-family house, whilst the 2-step can be used in both small and large scale applications, from domestic to industrial uses. In terms of overall solar-to-CH4 energy efficiency, the 2-step method reaches 13.26{%} against the 9.18{%} reached by the 1-step method. Next, the application of the direct solar methane technology is analysed for domestic buildings, in different European locations, equipped with a combination of solar thermal collectors (STCs) and PV panels, in which the heating needs that cannot be fulfilled by the STCs are satisfied by the combustion of methane synthesized by the PV-powered electrolyzers. Various combinations of situations for a whole year were studied and it was found that this auxiliary system can produce, per m2 of PV area, in the worst case scenario 23.6 g/day (0.328 kWh/day) of methane in Stockholm, and in the best case scenario 47.4 g/day (0.658 kWh/day) in Lisbon.

Marques, Marta, Bruno J. Guerreiro, Rita Cunha, and Carlos Silvestre. "Trajectory planning and control for drone replacement for multidrone cinematography." 21st IFAC Symposium on Automatic Control in Aerospace (ACA 2019), IFAC-PapersOnLine. Vol. 52. 2019. 334-339. Abstract
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Torrisi, Giacomo, João S. Luis, Olalla Sanchez-Sobrado, Rosario Raciti, Manuel J. Mendes, Hugo Águas, Elvira Fortunato, Rodrigo Martins, and Antonio Terrasi. "{Colloidal-structured metallic micro-grids: High performance transparent electrodes in the red and infrared range}." Solar Energy Materials and Solar Cells. 197 (2019): 7-12. Abstract

One of the most promising approaches to produce industrial-compatible Transparent Conducting Materials (TCMs) with excellent characteristics is the fabrication of TCO/metal/TCO multilayers. In this article, we report on the electro-optical properties of a novel high-performing TCO/metal/TCO structure in which the intra-layer is a micro-structured metallic grid instead of a continuous thin film. The grid is obtained by evaporation of Ag through a mask of polystyrene colloidal micro-spheres deposited by the Langmuir-Blodgett method and partially dry-etched in plasma. IZO/Ag grid/IZO structures with different thicknesses and mesh dimensions have been fabricated, exhibiting excellent electrical characteristics (sheet resistance below 10 $Ømega$/□) and particularly high optical transmittance in the near-infrared spectral region as compared to planar (unstructured) TCM multilayers. Numerical simulations were also used to highlight the role of the Ag mesh parameters on the electrical properties.

Caeiro, Frederico, L{\'ı}gia Henriques-Rodrigues, and Dora Prata Gomes. "A simple class of reduced bias kernel estimators of extreme value parameters." Computational and Mathematical Methods (2019): e1025. AbstractWebsite
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Gavinho, Sílvia R., Pedro R. Prezas, Diogo J. Ramos, Isabel Sá‐Nogueira, Joao P. Borges, Carmo M. Lança, Jorge C. Silva, Célia MR Henriques, Eduardo Pires, Jakka Suresh Kumar, and M. P. F. Graça. "{Nontoxic glasses: Preparation, structural, electrical and biological properties}." International Journal of Applied Ceramic Technology (2019): ijac.13243. AbstractWebsite
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Alexandre, Miguel, Manuel Chapa, Sirazul Haque, Manuel J. Mendes, Hugo Águas, Elvira Fortunato, and Rodrigo Martins. "{Optimum Luminescent Down-Shifting Properties for High Efficiency and Stable Perovskite Solar Cells}." ACS Applied Energy Materials. 2 (2019): 2930-2938. AbstractWebsite
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Silva, Sara, Maria João Falcão Silva, Paula Couto, and Fernando Pinho. "Energetic Rehabilitation of Building Towards BIM Methodology." CIAC2019 - 1st Conference on Automation Innovation in Construction. Leiria 2019.
Pinho, Fernando F. S. "Curso de pós-Graduação em Construção e Reabilitação Sustentável da FCT NOVA." Jornal de Negócios. Ano XVI, Nº 4046 (2019).
Brandao Moniz, António, and Bettina-Johanna Krings. "Social conditions of human-machine interaction: decision, control, qualilification." Kolloquium at Weizenbaum Institute (2019). Berlin: Weizenbaum Institute, WZB, 2019. Abstract

Due to the ongoing technical advancements in robotics, new organizational and occupational impacts are expected in different sectors. The contribution of António Moniz and Bettina-Johanna Krings focuses on the social conditions under which technology is embedded into production processes. Thus, social distribution processes, demographic change, sustainability becomes more and more important when reflecting about "technology futures".
In particular they will ask:
How does automation change work & working conditions?
Which expectations on technology are strengthen-ing the concepts of work?
Which regulations and ethics principles must be considered (safety, autonomy, control)?
Which new competences and qualification dimen-sions will be raised for non-routine tasks in auto-mated environments?
Which new types of human-machine interaction can be developed with increased cyber-physical system application at the shopfloor?

da Silva, Pedro Boto Semblano, Corneliu Cismasiu, and José Vieira de Lemos. "Avaliação da vulnerabilidade sísmica de um arco em alvenaria utilizando o método dos elementos discretos." SÍSMICA 2019 - 11º Congresso Nacional de Sismologia e Enhenharia Sísmica. Lisboa 2019. final_sismica2019.pdf
Brandao Moniz, António. "Emerging problems of human-machine interaction and innovative solutions." Séminaire CRAN-Centre de Recherche en Automatique de Nancy. Nancy: Université de Nancy, 2019.
Rebelo, H. B., D. Lecompte, C. Cismaşiu, A. Jonet, B. Belkassem, and A. Maazoun. "3D printed PLA sacrificial honeycomb cladding blast mitigation." 18th International Symposium for the Interaction of Munitions with Structures (ISIEMS). Panama City Beach, FL, USA 2019.
Yang, Yongming, Hugo Biscaia, Manuel A. G. Silva, and Carlos Chastre. "Monotonic and quasi-static cyclic bond response of CFRP-to-steel joints after salt fog exposure." Composites Part B: Engineering. 168 (2019): 532-549. AbstractWebsite

Deterioration of adhesively bonded CFRP/steel systems in salt fog environment, i.e., deicing salts and ocean environments, has to be taken into account in the design of steel strengthened structures. In the present work, monotonic and quasi-static cyclic loading were applied to CFRP-to-steel double strap joints for two kinds of CFRP laminates after being aged for a period of 5000 h to evaluate the bond behavior. The bonded joints exposed to salt fog had a different failure mode than that observed in the control specimens (0 h of exposure). The severe reduction of the maximum bond stress resulted from damage initiation that occurred in the corrosion region of the steel substrate, associated with final partial rupture on the corroded steel substrate around the edge of the bonded area: it was also correlated with reduced load carrying capacity. Results of pseudo-cyclic tests showed that the relationship between a local damage parameter (D) and normalized local dissipated energy (Wd/Gf) and the normalized slip increment (ΔS/ΔSult) exhibited almost the same trend in the un-aged and aged bonded joints. The normalized slip increment can be seen as a direct indicator for the local and global damage for the un-aged and aged bonded joints. However, monotonic and quasi-static cyclic tests results revealed that the stress concentration due to local corrosion of steel substrate could lead to brittle rupture or accelerated cumulative damage once the aged bonded interface had become weaker. The bonded joints have exhibited also a smaller relative deformation capacity between CFRP and steel.

Pacheco, João Nuno, Jorge de Brito, Carlos Chastre, and Luís Evangelista. "Statistical analysis of Portuguese ready-mixed concrete production." Construction and Building Materials. 209 (2019): 283-294. AbstractWebsite

This paper evaluates and compares the statistics of compressive strength data from three Portuguese ready-mixed concrete plants. A hierarchical model showed that different groups of concrete strength records are not statistically equivalent, even if they were produced in the same plant and using the same concrete composition. This finding is related to autocorrelation. For the same specified strength class, compositions produced less often result in higher average compressive strength and variability. The statistics of one of the plants were quite different from those of the others, even though the concrete of this plant also complied with the specifications. It was found that the average compressive strength of a mix may be quite dependent on the plant that produced it, even if the compressive strength complies with quality control specifications. Conformity with the target slump and strength class was checked following the conformity criteria of EN 206-1 for continuous production. Nonconformity with slump is more frequent than failure to comply with the strength class. A bias factor for reliability analyses was proposed.

Pacheco, J., J. de Brito, C. Chastre, and L. Evangelista. "Uncertainty models of reinforced concrete beams in bending: code comparison and recycled aggregate incorporation." Journal of Structural Engineering. 145 (2019): 04019013. AbstractWebsite

The bias factor of the Eurocode 2 [CEN (European Committee for Standardization) (2008). Eurocode 2: Design of ConcreteStructures–Part 1-1: General Rules and Rules for Buildings] and ACI 318 [ACI (American Concrete Institute) (2014). Building CodeRequirements for Structural Concrete and Commentary] flexural resistance models of reinforced concrete beams are compared withemphasis on the effect of the incorporation of coarse recycled aggregates sourced from concrete waste. The bias factor of the yielding momentcalculations according to both codes is also investigated, and the bias in the cracking moment when Eurocode 2 material clauses are used. Thedatabase was composed of 174 beams, and the criteria that led to its development are discussed. The effect of recycled aggregate incorporationon the statistical descriptors of the bias factor is evaluated and probabilistic modeling using lognormal distributions is argued for. Preliminarypartial safety factors for the bias factor of recycled aggregate concrete beams are proposed. No significant differences in the bias of theultimate moment were found between the two comparison vectors: Eurocode 2 versus ACI 318 specifications and recycled versus naturalcoarse aggregate. The bias of the cracking moment increased when coarse recycled aggregates were incorporated, most probably due to thehigher heterogeneity of recycled aggregates.

Pacheco, J., J. de Brito, C. Chastre, and L. Evangelista. "Experimental investigation on the variability of the main mechanical properties of concrete produced with coarse recycled concrete aggregates." Construction and Building Materials. 201 (2019): 110-120. AbstractWebsite

Research on the variability of the properties of recycled aggregate concrete is lacking and is necessary for the development of reliability analyses and code calibration procedures. This paper presents an experimental programme on the within-batch variability of the compressive strength, Young’s modulus, and splitting tensile strength of several recycled and natural aggregate concrete mixes. The influence of the recycled concrete aggregates on the mechanical properties and variability of concrete is analysed and discussed and benchmarks with standard predictions for the variability of natural aggregate concrete are made. It was found that full recycled aggregate concrete incorporation did not increase the variability of any of the properties tested, but intermediate ratios of recycled aggregate incorporation did. The properties of high-strength concrete mixes were more variable than that of all other mixes, irrespective of recycled aggregate incorporation. All properties of all compositions were suitably modelled by normal distributions. The coarse recycled aggregates were sourced from concrete waste.

Yang, Yongming, Manuel A. G. Silva, Hugo Biscaia, and Carlos Chastre. "Bond durability of CFRP laminates-to-steel joints subjected to freeze-thaw." Composite Structures. 212 (2019): 243-258. AbstractWebsite

The degradation mechanisms of bonded joints between CFRP laminates and steel substrates under severe environmental conditions require more durability data and studies to increase the database and better understand their causes. Studies on bond properties of double-strap CFRP-to-steel bonded joints with two different composite materials as well as adhesive coupons subjected to freeze-thaw cycles for 10,000 h were conducted to reduce that gap. In addition, the equivalent to the number of thermal cycles and their slips induced in the CFRP laminates was replicated by an equivalent (mechanical) loading-unloading history condition imposed by a static tensile machine. The mechanical properties of the adhesive coupons and the strength capacity of the bonded joints were only slightly changed by the artificial aging. It was confirmed that the interfacial bond strength between CFRP and adhesive is critically related to the maximum shear stress and failure mode. The interfacial bond strength between adhesive and steel degraded with the aging. However, the equivalent thermal cyclic bond stress caused no detectable damage on the bond because only the interfacial elastic regime was actually mobilized, which confirmed that pure thermal cycles aging, per se, at the level imposed, have a low impact on the degradation of CFRP-to-steel bonded joints.

Biscaia, Hugo C., Carlos Chastre, and Manuel A. G. Silva. "Estimations of the debonding process of aged joints through a new analytical method." Composite Structures. 211 (2019): 577-595. AbstractWebsite

The estimation of the long-term durability of adhesively bonded interfaces between Fiber Reinforced Polymers (FRP) and concrete substrates is crucial because degradation potentiates FRP premature debonding. One of the main reasons for mistrusting the use of FRP composites is the premature debonding phenomenon, which, associated to degradation, has been preventing their widespread use. In this research work, an analytical model is proposed that introduces ageing to estimate the effects of degradation of Glass (G) FRP externally bonded to concrete. Cycles were used to experimentally accelerate ageing of beam specimens, namely, (i) salt fog cycles; (ii) wet-dry cycles with salted water; (iii) temperature cycles between −10 °C and +30 °C; and (iv) temperature cycles between +7.5 °C and +47.5 °C. Based on the experimental results obtained and a corresponding bond-slip curve, the analytical model predicts the complete debonding process between FRP composites and a substrate. Consequently, the temporal evolution of the degradation of the bonded interfaces can be calculated and compared with the initial situation prior to exposure. The effects of the environmental conditions are reported and compared.

Gião, Rita, Valter Lúcio, and Carlos Chastre. "Gravity load effects on the behaviour of reinforced concrete beam critical zones subjected to cyclic loads." Engineering Structures. 181 (2019): 503-518. AbstractWebsite

The aim of the present study was to proceed to a numerical analysis of the gravity load effects on the behaviour of reinforced concrete beam critical zones when subjected to cyclic loads. A parametric study to assess the influence of different levels of gravity load on RC beam critical zones subjected to cyclic loading was carried out. For this purpose, assuming the level of gravity load as a variable parameter, a nonlinear numerical model of a beam-column connection, previously calibrated with experimental data, was used. In order to evaluate the gravity load effects in the global response, a numerical study of a RC frame system is also presented. The numerical results are analysed in terms of global hysteretic response, accumulated energy dissipation and equivalent viscous damping ratio. In this numerical study, it was observed that the hysteretic response depends on the load path. In the presence of higher gravity load levels, the structure hysteretic behaviour exhibits higher damage levels, associated to a failure mechanism corresponding to the formation of four span plastic hinges. Thus, the proper test procedure should involve the imposition of a reverse cyclic displacement history starting each cycle from the gravity load effects.

Chaparro, Catarina IP, Liliana R. Loureiro, Manuel Almeida Valente, Paula A. Videira, Joao Paulo Borges, and Paula I. P. Soares. "Application of Hyperthermia for Cancer Treatment: Synthesis and Characterization of Magnetic Nanoparticles and their internalization on Tumor Cell Lines." IEEE, 2019. 1-4. Abstract
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