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J.C.C. Abrantes
ProMetheus-Research Unit in Materials, Energy and Environment for Sustainability, Instituto Politécnico de Viana do Castelo, 4900-347 Viana do Castelo, Portugal

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Journal article
Published: 18 February 2021 in Sustainability
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The present study aimed to optimize the struvite chemical precipitation process in nitrogen-rich anaerobic co-digestion systems. Struvite precipitation experiments were carried out using a mixture of cattle slurry liquid fraction and sewage sludge, with and without ultrasound pretreatment. Marine salt or MgCl2 were used as magnesium source in NH4 +:Mg2+ stoichiometric proportions of 1:1.5 and 1:3. Under the tested conditions, ammonium nitrogen and orthophosphate were removed from the mixed liquor with a maximum observed efficiency of 43% and 92%, respectively, when the ultrasound treatment was applied prior to struvite precipitation, using MgCl2 as source of magnesium (NH4 +:Mg2+ of 1:3). The operating time was 40 min. Different pretreatments were tested prior to the biomethanization experiments, struvite precipitation, ultrasound, or a combination of both pretreatments. The application of ultrasound (with an energy input of 218 kJ L−1) and struvite precipitation (NH4 +:Mg2+ of 1:3) increased the methane content in the biogas by 82% and reduced hydraulic retention time by 28%, when compared to the anaerobic co-digestion assays without pretreatment. The hydrolytic pretreatment increased the bioavailability of nitrogen by 5%, thus enhancing the removal efficiency of ammonium nitrogen by 20%. Consequently, an increase in the carbon to nitrogen ratio was observed, favoring the methanogenesis process.

ACS Style

Renata Coura; Ana Rodrigues; Joaquim Alonso; Ana Ferraz; Luis Brito; João Abrantes; António Guerreiro Brito. Combined Pretreatment by Ultrasound and Struvite Precipitation of Raw Substrates: A Strategy to Overcome C/N Ratio Unbalance in Nitrogen-Rich Anaerobic Co-Digestion Systems. Sustainability 2021, 13, 2175 .

AMA Style

Renata Coura, Ana Rodrigues, Joaquim Alonso, Ana Ferraz, Luis Brito, João Abrantes, António Guerreiro Brito. Combined Pretreatment by Ultrasound and Struvite Precipitation of Raw Substrates: A Strategy to Overcome C/N Ratio Unbalance in Nitrogen-Rich Anaerobic Co-Digestion Systems. Sustainability. 2021; 13 (4):2175.

Chicago/Turabian Style

Renata Coura; Ana Rodrigues; Joaquim Alonso; Ana Ferraz; Luis Brito; João Abrantes; António Guerreiro Brito. 2021. "Combined Pretreatment by Ultrasound and Struvite Precipitation of Raw Substrates: A Strategy to Overcome C/N Ratio Unbalance in Nitrogen-Rich Anaerobic Co-Digestion Systems." Sustainability 13, no. 4: 2175.

Journal article
Published: 16 December 2020 in Biomedical Materials
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A F M Rodrigues; P M C Torres; M J S Barros; R Presa; N Ribeiro; J C C Abrantes; J H Belo; J S Amaral; M Bañobre-López; A Bettencourt; A Sousa; S M Olhero. Effective production of multifunctional magnetic-sensitive biomaterial by an extrusion-based additive manufacturing technique. Biomedical Materials 2020, 16, 015011 .

AMA Style

A F M Rodrigues, P M C Torres, M J S Barros, R Presa, N Ribeiro, J C C Abrantes, J H Belo, J S Amaral, M Bañobre-López, A Bettencourt, A Sousa, S M Olhero. Effective production of multifunctional magnetic-sensitive biomaterial by an extrusion-based additive manufacturing technique. Biomedical Materials. 2020; 16 (1):015011.

Chicago/Turabian Style

A F M Rodrigues; P M C Torres; M J S Barros; R Presa; N Ribeiro; J C C Abrantes; J H Belo; J S Amaral; M Bañobre-López; A Bettencourt; A Sousa; S M Olhero. 2020. "Effective production of multifunctional magnetic-sensitive biomaterial by an extrusion-based additive manufacturing technique." Biomedical Materials 16, no. 1: 015011.

Paper
Published: 24 January 2020 in Dalton Transactions
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Structure, conductivity and magnetism of orthorhombic and fluorite Ln10Mo2O21 (Ln = Gd, Dy, Ho) polymorphs.

ACS Style

Anna V. Shlyakhtina; Maxim Avdeev; Nikolay Viktorovich Lyskov; João C.C. Abrantes; E. Gomes; Ksenia Denisova; I. V. Kolbanev; Sergei Chernyak; O. S. Volkova; Alexander Vasiliev. Structure, conductivity and magnetism of orthorhombic and fluorite polymorphs in MoO3–Ln2O3 (Ln = Gd, Dy, Ho) systems. Dalton Transactions 2020, 49, 2833 -2842.

AMA Style

Anna V. Shlyakhtina, Maxim Avdeev, Nikolay Viktorovich Lyskov, João C.C. Abrantes, E. Gomes, Ksenia Denisova, I. V. Kolbanev, Sergei Chernyak, O. S. Volkova, Alexander Vasiliev. Structure, conductivity and magnetism of orthorhombic and fluorite polymorphs in MoO3–Ln2O3 (Ln = Gd, Dy, Ho) systems. Dalton Transactions. 2020; 49 (9):2833-2842.

Chicago/Turabian Style

Anna V. Shlyakhtina; Maxim Avdeev; Nikolay Viktorovich Lyskov; João C.C. Abrantes; E. Gomes; Ksenia Denisova; I. V. Kolbanev; Sergei Chernyak; O. S. Volkova; Alexander Vasiliev. 2020. "Structure, conductivity and magnetism of orthorhombic and fluorite polymorphs in MoO3–Ln2O3 (Ln = Gd, Dy, Ho) systems." Dalton Transactions 49, no. 9: 2833-2842.

Journal article
Published: 01 December 2019 in Materials Science and Engineering: C
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Cuttlefish bone (CB) has been explored as biomaterial in the bone tissue-engineering field due to its unique porous structure and capacity of the aragonite mineral to be hydrothermally converted into calcium phosphates (CaPs). In the present study, undoped and ion (Sr2+, Mg2+ and/or Zn2+) doped biphasic calcium phosphate (BCP) scaffolds were prepared by hydrothermal transformation (HT, 200 °C, 24 h) of CB. The obtained scaffolds were sintered and then coated with two commercial polymers, poly(ε-caprolactone) (PCL) or poly(DL-lactide) (PDLA), and with two synthesized ones, a poly(ester amide) (PEA) or a poly(ester urea) (PEU) in order to improve their compressive strength. The scaffolds were characterized by X-ray diffraction (XRD) coupled with structural Rietveld refinement, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The results demonstrate that CB could be entirely transformed into BCPs in the presence or absence of doping elements. The initial CB structure was preserved and the polymeric coatings did not jeopardize the interconnected porous structure. Furthermore, the polymeric coatings enhanced the compressive strength of the scaffolds. The in vitro bio-mineralization upon immersing the scaffolds into simulated body fluid (SBF) demonstrated the formation of bone-like apatite surface layers in both uncoated and coated scaffolds. Overall, the produced scaffolds exhibit promising properties for bone tissue engineering applications.

ACS Style

Ana Sofia Neto; Ana C. Fonseca; João Abrantes; Jorge Coelho; José M.F. Ferreira. Surface functionalization of cuttlefish bone-derived biphasic calcium phosphate scaffolds with polymeric coatings. Materials Science and Engineering: C 2019, 105, 110014 .

AMA Style

Ana Sofia Neto, Ana C. Fonseca, João Abrantes, Jorge Coelho, José M.F. Ferreira. Surface functionalization of cuttlefish bone-derived biphasic calcium phosphate scaffolds with polymeric coatings. Materials Science and Engineering: C. 2019; 105 ():110014.

Chicago/Turabian Style

Ana Sofia Neto; Ana C. Fonseca; João Abrantes; Jorge Coelho; José M.F. Ferreira. 2019. "Surface functionalization of cuttlefish bone-derived biphasic calcium phosphate scaffolds with polymeric coatings." Materials Science and Engineering: C 105, no. : 110014.

Journal article
Published: 01 August 2019 in Materials
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Sm2−xCaxZr2O7−x/2 (x = 0, 0.05, 0.1) and Gd2−xCaxZr2O7−x/2 (x = 0.05, 0.1) mixed oxides in a pyrochlore–fluorite morphotropic phase region were prepared via the mechanical activation of oxide mixtures, followed by annealing at 1600 °C. The structure of the solid solutions was studied by X-ray diffraction and refined by the Rietveld method, water content was determined by thermogravimetry (TG), their bulk and grain-boundary conductivity was determined by impedance spectroscopy in dry and wet air (100–900 °C), and their total conductivity was measured as a function of oxygen partial pressure in the temperature range: 700–950 °C. The Sm2−xCaxZr2O7−x/2 (x = 0.05, 0.1) pyrochlore solid solutions, lying near the morphotropic phase boundary, have proton conductivity contribution both in the grain bulk and on grain boundaries below 600 °C, and pure oxygen–ion conductivity above 700 °C. The 500 °C proton conductivity contribution of Sm2−xCaxZr2O7−x/2 (x = 0.05, 0.1) is ~ 1 × 10−4 S/cm. The fluorite-like Gd2−xCaxZr2O7−x/2 (x = 0.1) solid solution has oxygen-ion bulk conductivity in entire temperature range studied, whereas proton transport contributes to its grain-boundary conductivity below 700 °C. As a result, of the morphotropic phase transition from pyrochlore Sm2−xCaxZr2O7−x/2 (x = 0.05, 0.1) to fluorite-like Gd2−xCaxZr2O7−x/2 (x = 0.05, 0.1), the bulk proton conductivity disappears and oxygen-ion conductivity decreases. The loss of bulk proton conductivity of Gd2−xCaxZr2O7−x/2 (x = 0.05, 0.1) can be associated with the fluorite structure formation. It is important to note that the degree of Ca substitution in such solid solutions (Ln2−xCax)Zr2O7−δ (Ln = Sm, Gd) is low, x < 0.1. In both series, grain-boundary conductivity usually exceeds bulk conductivity. The high grain-boundary proton conductivity of Ln2−xCaxZr2O7−x/2 (Ln = Sm, Gd; x = 0.1) is attributable to the formation of an intergranular CaZrO3-based cubic perovskite phase doped with Sm or Gd in Zr sublattice.

ACS Style

A.V. Shlyakhtina; J.C.C. Abrantes; E. Gomes; N.V. Lyskov; E.Yu. Konysheva; Sergei Chernyak; E.P. Kharitonova; O.K. Karyagina; I.V. Kolbanev; L.G. Shcherbakova. Evolution of Oxygen–Ion and Proton Conductivity in Ca-Doped Ln2Zr2O7 (Ln = Sm, Gd), Located Near Pyrochlore–Fluorite Phase Boundary. Materials 2019, 12, 2452 .

AMA Style

A.V. Shlyakhtina, J.C.C. Abrantes, E. Gomes, N.V. Lyskov, E.Yu. Konysheva, Sergei Chernyak, E.P. Kharitonova, O.K. Karyagina, I.V. Kolbanev, L.G. Shcherbakova. Evolution of Oxygen–Ion and Proton Conductivity in Ca-Doped Ln2Zr2O7 (Ln = Sm, Gd), Located Near Pyrochlore–Fluorite Phase Boundary. Materials. 2019; 12 (15):2452.

Chicago/Turabian Style

A.V. Shlyakhtina; J.C.C. Abrantes; E. Gomes; N.V. Lyskov; E.Yu. Konysheva; Sergei Chernyak; E.P. Kharitonova; O.K. Karyagina; I.V. Kolbanev; L.G. Shcherbakova. 2019. "Evolution of Oxygen–Ion and Proton Conductivity in Ca-Doped Ln2Zr2O7 (Ln = Sm, Gd), Located Near Pyrochlore–Fluorite Phase Boundary." Materials 12, no. 15: 2452.

Journal article
Published: 09 January 2019 in Inorganic Chemistry Frontiers
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Based on rhombohedral structure (R3̄) complex Nd10Mo2O21 compound has proton conductivity ∼8 × 10−4 S cm−1 at 600 °C.

ACS Style

Anna V. Shlyakhtina; Maxim Avdeev; João C.C. Abrantes; E. Gomes; Nikolay Lyskov; E. P. Kharitonova; I. V. Kolbanev; L. G. Shcherbakova. Structure and conductivity of Nd6MoO12-based potential electron–proton conductors under dry and wet redox conditions. Inorganic Chemistry Frontiers 2019, 6, 566 -575.

AMA Style

Anna V. Shlyakhtina, Maxim Avdeev, João C.C. Abrantes, E. Gomes, Nikolay Lyskov, E. P. Kharitonova, I. V. Kolbanev, L. G. Shcherbakova. Structure and conductivity of Nd6MoO12-based potential electron–proton conductors under dry and wet redox conditions. Inorganic Chemistry Frontiers. 2019; 6 (2):566-575.

Chicago/Turabian Style

Anna V. Shlyakhtina; Maxim Avdeev; João C.C. Abrantes; E. Gomes; Nikolay Lyskov; E. P. Kharitonova; I. V. Kolbanev; L. G. Shcherbakova. 2019. "Structure and conductivity of Nd6MoO12-based potential electron–proton conductors under dry and wet redox conditions." Inorganic Chemistry Frontiers 6, no. 2: 566-575.

Journal article
Published: 01 January 2019 in Procedia Structural Integrity
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C. Oliveira; C. Reis; João Abrantes; L.T. Silva; P.L. Silva; J.F. Silva. Study of the dust produced in rehabilitation works. Procedia Structural Integrity 2019, 22, 144 -150.

AMA Style

C. Oliveira, C. Reis, João Abrantes, L.T. Silva, P.L. Silva, J.F. Silva. Study of the dust produced in rehabilitation works. Procedia Structural Integrity. 2019; 22 ():144-150.

Chicago/Turabian Style

C. Oliveira; C. Reis; João Abrantes; L.T. Silva; P.L. Silva; J.F. Silva. 2019. "Study of the dust produced in rehabilitation works." Procedia Structural Integrity 22, no. : 144-150.

Journal article
Published: 19 September 2018 in Materials Science and Engineering: C
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Advances on the fabrication of sintering-free biphasic calcium phosphate (BCP)/natural polymer composite scaffolds using robocasting as additive manufacturing technique are presented in the present work. Inks with high amounts of BCP powders (45 vol%) containing different HA/β-TCP ratios, in presence of crosslinked polymer, were successfully fine-tuned for extrusion by robocasting. The non-existence of sintering step opened the possibility to obtain drug loaded scaffolds by adding levofloxacin to the extrudable inks. The drug presence induced slightly changes on the rheological behaviour of the inks, more emphasized for the BCP compositions with higher amounts of β-TCP, and consequently, on the microstructure and on the mechanical properties of the final scaffolds. The strong interaction of β-TCP with chitosan difficult the preparation of suitable rheological inks for printing. Drug delivery studies revealed a fast release of levofloxacin with a high burst of drug within the first 30 min. Levofloxacin loaded samples also presented bacteria growth inhibition ability, proving that antibiotic was not degraded during the fabrication process and its bactericidal efficacy was preserved. From the results obtained, the composite scaffolds containing higher amounts of HA (around 80% HA/20% β-TCP) constitute a promising bi-functional synthetic bone substitute for simultaneous local bone regeneration and infection treatments.

ACS Style

Catarina F. Marques; Susana Olhero; Paula M C Torres; João Abrantes; Sara Fateixa; Helena Seguro Nogueira; Isabel Ribeiro; Ana Bettencourt; Aureliana Sousa; Pedro Granja; José M.F. Ferreira. Novel sintering-free scaffolds obtained by additive manufacturing for concurrent bone regeneration and drug delivery: Proof of concept. Materials Science and Engineering: C 2018, 94, 426 -436.

AMA Style

Catarina F. Marques, Susana Olhero, Paula M C Torres, João Abrantes, Sara Fateixa, Helena Seguro Nogueira, Isabel Ribeiro, Ana Bettencourt, Aureliana Sousa, Pedro Granja, José M.F. Ferreira. Novel sintering-free scaffolds obtained by additive manufacturing for concurrent bone regeneration and drug delivery: Proof of concept. Materials Science and Engineering: C. 2018; 94 ():426-436.

Chicago/Turabian Style

Catarina F. Marques; Susana Olhero; Paula M C Torres; João Abrantes; Sara Fateixa; Helena Seguro Nogueira; Isabel Ribeiro; Ana Bettencourt; Aureliana Sousa; Pedro Granja; José M.F. Ferreira. 2018. "Novel sintering-free scaffolds obtained by additive manufacturing for concurrent bone regeneration and drug delivery: Proof of concept." Materials Science and Engineering: C 94, no. : 426-436.

Journal article
Published: 01 August 2018 in Materials Characterization
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High quality factor and a temperature stable resonant frequency make BaLa4Ti4O15 (BLT) ceramics attractive materials for microwave applications. Aiming to exploit the effects of external stresses on the development of textured and anisotropic microstructures to optimise MW properties, the influence of applied external pressure during sintering of BLT ceramics is analysed. HRTEM and geometric phase analysis (GPA) showed that stresses applied during sintering, trigger the nucleation and growth of faults hypothesised to be due to the errors in the AO3 layer (basal plane) stacking sequence of the hexagonal perovskite structure. The results reveal a strong correlation between the high concentration of structural defects and the development of anisotropic microstructures, which tune the properties of BLT. Stresses applied during sintering are therefore a promising tool to design material properties.

ACS Style

Nivas Babu Selvaraj; Manuela Fernandes; Ian M. Reaney; João C.C. Abrantes; Thibaud Denneulin; Etienne Snoeck; Paula Maria Vilarinho; Ana Maria Senos. Linking sintering stresses to nano modification in the microstructure of BaLa4Ti4O15 by transmission electron microscopy. Materials Characterization 2018, 142, 1 -8.

AMA Style

Nivas Babu Selvaraj, Manuela Fernandes, Ian M. Reaney, João C.C. Abrantes, Thibaud Denneulin, Etienne Snoeck, Paula Maria Vilarinho, Ana Maria Senos. Linking sintering stresses to nano modification in the microstructure of BaLa4Ti4O15 by transmission electron microscopy. Materials Characterization. 2018; 142 ():1-8.

Chicago/Turabian Style

Nivas Babu Selvaraj; Manuela Fernandes; Ian M. Reaney; João C.C. Abrantes; Thibaud Denneulin; Etienne Snoeck; Paula Maria Vilarinho; Ana Maria Senos. 2018. "Linking sintering stresses to nano modification in the microstructure of BaLa4Ti4O15 by transmission electron microscopy." Materials Characterization 142, no. : 1-8.

Journal article
Published: 01 May 2018 in Ceramics International
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Alpha-tricalcium phosphate (α-TCP) is a component of particular interest in the formulation of apatitic calcium phosphate based bone cements. During the setting reaction of this type of cements, a calcium deficient hydroxyapatite with composition similar to bone hydroxyapatite is formed. But the purity levels of the commercially available products based on α-TCP are generally low, and their prices are prohibitive. Such stringent conditions are pushing most of the researchers in the area of bone cements towards preparing α-TCP in their own laboratories. The low degree of purity of α-TCP based products is generally due to an incomplete β-TCP → α-TCP phase transformation and/or to a partial α-TCP → β-TCP reversal during cooling. Despite extensive research efforts, contradictory reports exist about the effects of composition of the starting material, cooling rates and the importance of quenching for maintaining α-TCP purity. The present work aims at shedding further light on this issue by controlling the relevant parameters of wet synthesis of the starting β-TCP powders and their heat treatment schedule in order to transform them in high purity α-TCP products. The key experimental variables investigated included the composition of the starting β-TCP powders, namely the Ca/P ratio, the maximum heat treatment temperatures, and the cooling rates.

ACS Style

Daniela Brazete; Paula M C Torres; João Abrantes; J.M.F. Ferreira. Influence of the Ca/P ratio and cooling rate on the allotropic α↔β-tricalcium phosphate phase transformations. Ceramics International 2018, 44, 8249 -8256.

AMA Style

Daniela Brazete, Paula M C Torres, João Abrantes, J.M.F. Ferreira. Influence of the Ca/P ratio and cooling rate on the allotropic α↔β-tricalcium phosphate phase transformations. Ceramics International. 2018; 44 (7):8249-8256.

Chicago/Turabian Style

Daniela Brazete; Paula M C Torres; João Abrantes; J.M.F. Ferreira. 2018. "Influence of the Ca/P ratio and cooling rate on the allotropic α↔β-tricalcium phosphate phase transformations." Ceramics International 44, no. 7: 8249-8256.

Journal article
Published: 01 December 2017 in Ceramics International
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Catarina Marques; Susana Olhero; J.C.C. Abrantes; Ana Marote; Sónia Ferreira; Sandra I. Vieira; José Ferreira. Biocompatibility and antimicrobial activity of biphasic calcium phosphate powders doped with metal ions for regenerative medicine. Ceramics International 2017, 43, 15719 -15728.

AMA Style

Catarina Marques, Susana Olhero, J.C.C. Abrantes, Ana Marote, Sónia Ferreira, Sandra I. Vieira, José Ferreira. Biocompatibility and antimicrobial activity of biphasic calcium phosphate powders doped with metal ions for regenerative medicine. Ceramics International. 2017; 43 (17):15719-15728.

Chicago/Turabian Style

Catarina Marques; Susana Olhero; J.C.C. Abrantes; Ana Marote; Sónia Ferreira; Sandra I. Vieira; José Ferreira. 2017. "Biocompatibility and antimicrobial activity of biphasic calcium phosphate powders doped with metal ions for regenerative medicine." Ceramics International 43, no. 17: 15719-15728.

Journal article
Published: 01 June 2017 in Ceramics International
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ACS Style

N. Vitorino; F.A.C. Oliveira; T. Marcelo; J.C.C. Abrantes; B. Trindade. Corrigendum to “Electrical characterization of La9.33Si2Ge4O26 oxyapatite for prospective intermediate-temperature solid oxide fuel cells” [Ceram. Int. 43 (2017) 3847–3853]. Ceramics International 2017, 43, 6636 .

AMA Style

N. Vitorino, F.A.C. Oliveira, T. Marcelo, J.C.C. Abrantes, B. Trindade. Corrigendum to “Electrical characterization of La9.33Si2Ge4O26 oxyapatite for prospective intermediate-temperature solid oxide fuel cells” [Ceram. Int. 43 (2017) 3847–3853]. Ceramics International. 2017; 43 (8):6636.

Chicago/Turabian Style

N. Vitorino; F.A.C. Oliveira; T. Marcelo; J.C.C. Abrantes; B. Trindade. 2017. "Corrigendum to “Electrical characterization of La9.33Si2Ge4O26 oxyapatite for prospective intermediate-temperature solid oxide fuel cells” [Ceram. Int. 43 (2017) 3847–3853]." Ceramics International 43, no. 8: 6636.

Journals
Published: 15 March 2017 in Journal of Materials Chemistry B
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Combining Mn and Sr co-doping β-TCP powder with sucrose addition in the setting liquid enhances injectability, mechanical and biological performance of brushite-forming cements, renders them promising for minimally invasive surgery applications.

ACS Style

P. M. C. Torres; A. Marote; A. R. Cerqueira; António José Calado; J. C. C. Abrantes; Susana Olhero; Odete A. B. Da Cruz E Silva; S. I. Vieira; José Ferreira. Injectable MnSr-doped brushite bone cements with improved biological performance. Journal of Materials Chemistry B 2017, 5, 2775 -2787.

AMA Style

P. M. C. Torres, A. Marote, A. R. Cerqueira, António José Calado, J. C. C. Abrantes, Susana Olhero, Odete A. B. Da Cruz E Silva, S. I. Vieira, José Ferreira. Injectable MnSr-doped brushite bone cements with improved biological performance. Journal of Materials Chemistry B. 2017; 5 (15):2775-2787.

Chicago/Turabian Style

P. M. C. Torres; A. Marote; A. R. Cerqueira; António José Calado; J. C. C. Abrantes; Susana Olhero; Odete A. B. Da Cruz E Silva; S. I. Vieira; José Ferreira. 2017. "Injectable MnSr-doped brushite bone cements with improved biological performance." Journal of Materials Chemistry B 5, no. 15: 2775-2787.

Journal article
Published: 01 March 2017 in Materials & Design
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Nuno M.D. Vitorino; Andrei Kovalevsky; Marta Ferro; João Abrantes; Jorge Frade. Design of NiAl2O4 cellular monoliths for catalytic applications. Materials & Design 2017, 117, 332 -337.

AMA Style

Nuno M.D. Vitorino, Andrei Kovalevsky, Marta Ferro, João Abrantes, Jorge Frade. Design of NiAl2O4 cellular monoliths for catalytic applications. Materials & Design. 2017; 117 ():332-337.

Chicago/Turabian Style

Nuno M.D. Vitorino; Andrei Kovalevsky; Marta Ferro; João Abrantes; Jorge Frade. 2017. "Design of NiAl2O4 cellular monoliths for catalytic applications." Materials & Design 117, no. : 332-337.

Journal article
Published: 08 December 2016 in Ceramics International
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La9.33Si2Ge4O26 materials have been fabricated from La2O3, SiO2 and GeO2 powders by high speed mechanical alloying followed by conventional and microwave hybrid sintering at different temperatures and holding times. XRD data showed that the apatite phase is formed after 1 h of mechanical alloying at 850 rpm. This phase remained stable after conventional sintering in an electric furnace with density increasing as sintering temperatures and holding times were increased. However, the highest density was achieved for samples sintered in the microwave furnace (5.44 g cm−3), corresponding to a relative density of 98%. The electrical conductivity of the samples microwave sintered at 700 and 800 ºC are 4.72×10−3 and 1.93×10−2 S.cm−1, respectively, with a correspondent activation energy of 0.952 eV.

ACS Style

N. Vitorino; F.A.C. Oliveira; T. Marcelo; J.C.C. Abrantes; B. Trindade. Electrical characterization of La 9.33 Si 2 Ge 4 O 26 oxyapatite for prospective intermediate-temperature solid oxide fuel cells. Ceramics International 2016, 43, 3847 -3853.

AMA Style

N. Vitorino, F.A.C. Oliveira, T. Marcelo, J.C.C. Abrantes, B. Trindade. Electrical characterization of La 9.33 Si 2 Ge 4 O 26 oxyapatite for prospective intermediate-temperature solid oxide fuel cells. Ceramics International. 2016; 43 (4):3847-3853.

Chicago/Turabian Style

N. Vitorino; F.A.C. Oliveira; T. Marcelo; J.C.C. Abrantes; B. Trindade. 2016. "Electrical characterization of La 9.33 Si 2 Ge 4 O 26 oxyapatite for prospective intermediate-temperature solid oxide fuel cells." Ceramics International 43, no. 4: 3847-3853.

Journal article
Published: 01 September 2016 in Key Engineering Materials
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The use of some additions as cement replacement has played an important role in the amount of clinker reduction. Due to its huge worldwide availability one of the most important and recognised replace agent is the fly ash, but is also estimated that only 30 to 40% of fly ash is used, although there are some challenges to be overcome, such as the reactive potential quantification. Chemical analysis is typically determined by the oxides content and does not take into account the vitreous and crystalline phase ratio. Therefore, this paper describes in detail one selective dissolution method, based in the hydrofluoric acid attack, to the quantification of the vitreous phase (reactive) and crystalline phases (not reactive). Fly ash from Portuguese Pego thermoelectric power plant was submitted to different attacks. To confirm the method and its effects, chemical and physical analysis were performed, such as STA, XRF, XRD with Rietveld refinement, SEM, EDS and laser diffraction granulometry. The results can be used to quantify the potential reactivity of this type of fly ash. The best results were achieved with 1% hydrofluoric acid attack during 6 hours.

ACS Style

Rui Reis; M.J.P. Ribeiro; João Abrantes; Aires Camões; Elisabete Teixeira; Raphaele Malheiro. Methodology for Analysis of the Reactivity of Coal Fly Ash Using Selective Dissolution by Hydrofluoric Acid. Key Engineering Materials 2016, 711, 1126 -1133.

AMA Style

Rui Reis, M.J.P. Ribeiro, João Abrantes, Aires Camões, Elisabete Teixeira, Raphaele Malheiro. Methodology for Analysis of the Reactivity of Coal Fly Ash Using Selective Dissolution by Hydrofluoric Acid. Key Engineering Materials. 2016; 711 ():1126-1133.

Chicago/Turabian Style

Rui Reis; M.J.P. Ribeiro; João Abrantes; Aires Camões; Elisabete Teixeira; Raphaele Malheiro. 2016. "Methodology for Analysis of the Reactivity of Coal Fly Ash Using Selective Dissolution by Hydrofluoric Acid." Key Engineering Materials 711, no. : 1126-1133.

Journal article
Published: 01 September 2016 in Energy Conversion and Management
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Selection guidelines are primary criterion for optimization of materials for specific applications in order to meet simultaneous and often conflicting requirements. This is mostly true for technologies and products required to meet the main societal needs, such as energy. In this case, gaps between supply and demand require strategies for energy conversion and storage, including thermal storage mostly based on phase change materials. Latent heat storage is also very versatile for thermal management and thermal control by allowing high storage density within narrow temperature ranges without strict dependence between stored thermal energy and temperature. Thus, this work addressed the main issues of latent heat storage from a materials selection perspective, based on expected requirements of applications in thermal energy storage or thermal regulation. Representative solutions for the kinetics of latent heat charge/discharge were used to derive optimization guidelines for high energy density, high power, response time (from fast response to thermal inertia), etc. The corresponding property relations were presented in graphical forms for a wide variety of prospective phase change materials, and for wide ranges of operating conditions, and accounting for changes in geometry and mechanisms. (C) 2016 Elsevier Ltd. All rights reserved

ACS Style

Nuno Vitorino; João Abrantes; Jorge Frade. Quality criteria for phase change materials selection. Energy Conversion and Management 2016, 124, 598 -606.

AMA Style

Nuno Vitorino, João Abrantes, Jorge Frade. Quality criteria for phase change materials selection. Energy Conversion and Management. 2016; 124 ():598-606.

Chicago/Turabian Style

Nuno Vitorino; João Abrantes; Jorge Frade. 2016. "Quality criteria for phase change materials selection." Energy Conversion and Management 124, no. : 598-606.

Journal article
Published: 01 August 2016 in Materials Science Forum
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Cellular ceramics were prepared by emulsification of aqueous alumina suspensions with liquid paraffin, using collagen as a shape stabilizer and a dispersant to adjust viscosity. Rheological measurements of emulsions and microstructural analysis of the sintered samples were performed. The results show that the concentration of collagen, dispersant content and stirring rate affect directly the emulsion viscosity which causes changes in porosity and average cell size.

ACS Style

Mariana Ferreira Sanches; Nuno Miguel Dias Vitorino; João Carlos De Castro Abrantes; Jorge Ribeiro Frade; João Batista Rodrigues Neto; Dachamir Hotza. Rheological Behavior of Paraffin-Alumina Emulsions and their Microstructural Effects. Materials Science Forum 2016, 869, 85 -90.

AMA Style

Mariana Ferreira Sanches, Nuno Miguel Dias Vitorino, João Carlos De Castro Abrantes, Jorge Ribeiro Frade, João Batista Rodrigues Neto, Dachamir Hotza. Rheological Behavior of Paraffin-Alumina Emulsions and their Microstructural Effects. Materials Science Forum. 2016; 869 ():85-90.

Chicago/Turabian Style

Mariana Ferreira Sanches; Nuno Miguel Dias Vitorino; João Carlos De Castro Abrantes; Jorge Ribeiro Frade; João Batista Rodrigues Neto; Dachamir Hotza. 2016. "Rheological Behavior of Paraffin-Alumina Emulsions and their Microstructural Effects." Materials Science Forum 869, no. : 85-90.

Journal article
Published: 01 April 2016 in International Journal of Hydrogen Energy
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This paper examines the effect of the Pr3+/Pr4+ ratio on the mechanism of ionic and electronic transport in the (Pr2−xZrx)Zr2O7+x/2 (x = 0.15), Pr2Zr2O7, and Pr2(Zr2−xPrx)O7−x/2 (x = 0.1) pyrochlore phases and Pr3ZrOx with the fluorite structure and on the behavior of their thermal expansion coefficient (TEC). The solid solutions were prepared through coprecipitation followed by firing of the green compacts in air at a high temperature of 1550 °C for 4 h. The Pr3+/Pr4+ ratio was shown to decrease in going from the (Pr2−xZrx)Zr2O7+x/2 (x = 0.15), Pr2Zr2O7, and Pr2(Zr2−xPrx)O7−x/2 (x = 0.1) pyrochlores to the Pr3ZrOx fluorite, leading to changes in the conductivity type from mixed (ionic–electronic) to electronic and in the color of the materials from beige to black and to an anomalous deviation of the TEC from linearity in fluorite Pr3ZrOx, i.e. at the highest Pr4+ content. According to impedance spectroscopy results, (Pr2−xZrx)Zr2O7+x/2 with x = 0.15 has purely oxide-ion conductivity (3 × 10−3 S/cm at 1000 °C) in a wide range of oxygen partial pressures: from 10−10 to 102 Pa. With increasing Pr content, p-type electronic conductivity becomes significant, reaching a maximum in fluorite Pr3ZrOx: ∼0.5 S/cm at 1000 °C. According to XPS data, all pyrochlore samples (Pr2−xZrx)Zr2O7+x/2 (x = 0.15), Pr2Zr2O7 and Pr2(Zr2−xPrx)O7−x/2 (x = 0.1) contain only Pr3+ at room temperature, whereas Pr3ZrOx contains both Pr3+ and Pr4+. The considerable deviation of the TEC of Pr3ZrOx from linearity above 500 °C is due to partial reduction of Pr4+. The reduction process Pr4+ + e′ → Pr3+ followed by oxygen release in the range 500–1100 °C has been identified in Pr3ZrOx by thermal analysis and mass spectrometry in a He atmosphere.

ACS Style

A.V. Shlyakhtina; J.C.C. Abrantes; E. Gomes; A.N. Shchegolikhin; G.A. Vorobieva; K.I. Maslakov; A.V. Knotko; L.G. Shcherbakova. Effect of Pr3+/Pr4+ ratio on the oxygen ion transport and thermomechanical properties of the pyrochlore and fluorite phases in the ZrO2–Pr2O3 system. International Journal of Hydrogen Energy 2016, 41, 9982 -9992.

AMA Style

A.V. Shlyakhtina, J.C.C. Abrantes, E. Gomes, A.N. Shchegolikhin, G.A. Vorobieva, K.I. Maslakov, A.V. Knotko, L.G. Shcherbakova. Effect of Pr3+/Pr4+ ratio on the oxygen ion transport and thermomechanical properties of the pyrochlore and fluorite phases in the ZrO2–Pr2O3 system. International Journal of Hydrogen Energy. 2016; 41 (23):9982-9992.

Chicago/Turabian Style

A.V. Shlyakhtina; J.C.C. Abrantes; E. Gomes; A.N. Shchegolikhin; G.A. Vorobieva; K.I. Maslakov; A.V. Knotko; L.G. Shcherbakova. 2016. "Effect of Pr3+/Pr4+ ratio on the oxygen ion transport and thermomechanical properties of the pyrochlore and fluorite phases in the ZrO2–Pr2O3 system." International Journal of Hydrogen Energy 41, no. 23: 9982-9992.

Journal article
Published: 14 March 2016 in Microscopy and Microanalysis
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Manuela A.C. Fernandes; João P. Bóia; Nivas Babu Selvaraj; João C.C. Abrantes; Ana M.R. Senos; Paula M. Vilarinho. Statistical analysis of grain size distributions in pressure-assisted BaLa4Ti4O15 microstructures. Microscopy and Microanalysis 2016, 22, 36 -37.

AMA Style

Manuela A.C. Fernandes, João P. Bóia, Nivas Babu Selvaraj, João C.C. Abrantes, Ana M.R. Senos, Paula M. Vilarinho. Statistical analysis of grain size distributions in pressure-assisted BaLa4Ti4O15 microstructures. Microscopy and Microanalysis. 2016; 22 (S4):36-37.

Chicago/Turabian Style

Manuela A.C. Fernandes; João P. Bóia; Nivas Babu Selvaraj; João C.C. Abrantes; Ana M.R. Senos; Paula M. Vilarinho. 2016. "Statistical analysis of grain size distributions in pressure-assisted BaLa4Ti4O15 microstructures." Microscopy and Microanalysis 22, no. S4: 36-37.