Listar QICM - Artículos por título
Mostrando ítems 11-30 de 117
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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 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 ... -
“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 ... -
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, ... -
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, ... -
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 ... -
Effect of calcium sulfate source on the hydration of calcium sulfoaluminate eco-cement
(2014)The availability of cements, including eco-cements, with tailored mechanical properties is very important for special applications in the building industry. Here we report a full study of the hydration of calcium sulfoaluminate ... -
Effect of Microencapsulated Phase Change Materials on the Flow Behavior of Cement Composites
(2019)Microencapsulated phase change materials (MPCMs) were incorporated into cement pastes of Portland cement (PC). Minislump tests and rheological properties of cement pastes containing three MPCMs with different surfaces ... -
Effect of Zn addition on the structure and electrochemical properties of codoped BaCe0.6Zr0.2Ln0.2O3-δ (Ln=Y, Gd, Yb) proton conductors
(Elsevier, 2018-05-02)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 ... -
The effects of MgO, Na2O and SO3 on industrial clinkering process: phase composition, polymorphism, microstructure and hydration, using a multidisciplinary approach
(2019-07-02)The present investigation deals with how minor elements (their oxides: MgO, Na2O and SO3) in industrial kiln feeds affect (i) chemical reactions upon clinkering, (ii) resulting phase composition and microstructure ... -
Effects of sulfates on the hydration of Portland cement – A review
(2021)Presented within is a critical overview of the effect of sulfates on cement hydration, properties, and optimum sulfate content in Portland cement. Calcium sulfate is used in Portland cement to control the C3A reaction ...