Listar QICM - Artículos por título
Mostrando ítems 11-30 de 133
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Belite cements and their activation
(Elsevier, 2020-11)Belite cements, BCs, containing mainly belite, alite and calcium aluminates, are currently used as low heat cements. These binders produce high amounts of C–S–H gel and have very good durability properties which are reviewed. ... -
Belite clinkers with increasing aluminium content: effect of calcium aluminates on calcium silicate hydration
(Elsevier, 2022)Belite cements (BCs) could have advantages over Portland cements concerning durability, low heat development and the use of less demanding raw materials. The activation of BCs by sulfur addition at the clinkering stage and ... -
Belite hydration at high temperature and pressure by in situ synchrotron powder diffraction
(2020-10-16)Portland cements are currently used as Oil‐Well‐Cements for the sheath between the metal casing and the borehole. At high pressures and temperatures, the resulting C-S-H gel(s) is partly unstable and it can react to give ... -
Bimetallic Niobium-Based Catalysts Supported on SBA-15 for Hydrodeoxygenation of Anisole
(ACS, 2021-12-17)The effect of adding iron, cobalt or nickel to a prepared niobium-supported catalyst using mesoporous silica SBA-15 as a support was evaluated in the hydrodeoxygenation (HDO) reaction of anisole, chosen as a model compound ... -
Boosting the Performance of La0.8Sr0.2MnO3-δ Electrodes by The Incorporation of Nanocomposite Active Layers
(Wiley, 2022-07-07)The use of active layers is a promising strategy to improve the properties of air electrodes for solid oxide fuel cells (SOFCs). In this work, La0.8Sr0.2MnO3-δ is combined with different oxide ion conductors Ce0.9Gd0.1O1.95, ... -
“Breathing” in Adsorbate-Responsive Metal Tetraphosphonate Hybrid Materials
(Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim, 2009-05-28)The structures of various layered calcium tetraphosphonates (CaH6DTMP; H8DTMP=hexamethyl- tetrakis(methylenephosphonic acid)), have been determined. Starting from CaH6DTMP·2H2O, thermal treatment and subsequent exposure ... -
C-S-H seeding activation of Portland and Belite cements: An enlightening in situ synchrotron powder diffraction study
(Elsevier, 2022-11)C-S-H seeding in Portland cements is well known from basic scientific works and field applications. Moreover, this activation approach could be beneficial for low-CO2 cements under development where a general drawback is ... -
Calcium aluminate cement conversion analysed by ptychographic nanotomography
(Elsevier, 2020-08-17)Calcium aluminate cements are used for special applications but are nowadays banned for general structural purposes due to the calcium aluminate hydrate conversion, that has led, for concretes fabricated with high water ... -
Catalytic Activity of Mixed Al2O3-ZrO2 Oxides for Glucose Conversion into 5-Hydroxymethylfurfural
(MDPI, 2020-08-04)In the present work, a series of catalysts based on aluminum and zirconium oxides was studied for the transformation of glucose into 5-hydroxymethylfurfural. These catalysts were characterized by using experimental techniques, ... -
Catalytic transfer hydrogenation of furfural to furfuryl alcohol over calcined MgFe hydrotalcites
(Elsevier B.V., 2019-11-07)Catalytic transfer hydrogenation is an alternative catalytic approach for the reduction of carbonyl groups, instead of the use of dihydrogen gas. In this sense, a series of catalysts has been prepared by thermal treatment ... -
Chemistry and Mass Density of Aluminum Hydroxide Gel in Eco-Cements by Ptychographic X-ray Computed Tomography
(ACS, 2017)Eco-cements are a desirable alternative to ordinary Portland cements because of their lower CO2 footprints. Some ye’elimite-based ecocements are attracting a lot of interest. Understanding the reasons for the mechanical ... -
Clinkering and hydration of belite-ye'elimite-alite cement
(Elsevier, 2017)Some belite-ye´elimite-ferrite (BYF) cements present low mechanical strengths mainly due to the slow reactivity of belite. A solution to this problem may be the activation of BYF clinkers by preparing them with a coexistence ... -
Common Structural Features in Calcium Hydroxyphosphonoacetates. A High-Throughput Screening
(2011-03-11)R,S-Hydroxyphosphonoacetic acid (H3HPA) is an inexpensive multidentate organic ligand widely used for the preparation of organo-inorganic hybrid materials. There are reports of several crystal structures and the variability ... -
A comparative study of experimental configurations in synchrotron pair distribution function
(MDPI - Publisher of Open Access Journals, 2019-04-25)The identification and quantification of amorphous components and nanocrystalline phases with very small crystal sizes, smaller than ~3 nm, within samples containing crystalline phases is very challenging. However, this ... -
Crystal engineering in confined spaces. A novel method to grow crystalline metal phosphonates in alginate gel systems
(The Royal Society of Chemistry, 2012)In this paper we report a crystal growth method for metal phosphonate frameworks in alginate gels. It consists of a metalcontaining alginate gel, in which a solution of phosphonate ligand is slowly diffused. Crystals of ... -
Difracción de rayos-x (DRX) y cementos: desde la investigación hasta el control de calidad
(2019-06-20)Los materiales de construcción son componentes complejos de gran interés comercial. Por ello, el conocimiento cuantitativo de su mineralogía a través de la difracción de rayos X (DRX) es de crucial importancia para optimizar ... -
Divalent Metal Vinylphosphonate Layered Materials: Compositional Variability, Structural Peculiarities, Dehydration Behavior, and Photoluminescent Properties
(American Chemical Society, 2011-09-27)A family of M-VP (M = Ni, Co, Cd, Mn, Zn, Fe, Cu, Pb; VP = vinylphosphonate) and M-PVP (M = Co, Cd; PVP = phenylvinylphosphonate) materials have been synthesized by hydrothermal methods and characterized by FTIR, elemental ... -
Durability and performance of CGO barriers and LSCF cathode deposited by spray-pyrolysis
(Elsevier, 2018-03-19)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, ... -
Early-age reactivity of calcined kaolinitic clays in LC3 cements: a multitechnique investigation including pair distribution function analysis
(Taylor & Francis, 2022-09)Limestone Calcined Clay Cements, LC3, allows CO2 emissions savings up to 40%. The resulting binders have competitive mechanical performances after a week. However, the reactivity of LC3 at early ages is slow and should be ... -
Effect of boron and water-to-cement ratio on the performances of laboratory prepared Belite-Ye'elimite-Ferrite (BYF) cements
(2021)The effect of superplasticiser, borax and the water-to-cement ratio on BYF hydration and mechanical strengths has been studied. Two laboratory-scale BYF cements—st-BYF (with -C2S and orthorhombic C4A3 S) and borax-activated ...