It is now well accepted and demonstrated that calcium silicate, calcium aluminate and calcium sulfo aluminate (ettringite, AFm) phases exhibit a good capability to fix metals and metalloids. Unfortunately the role of minor phases and especially calcium-ferric aluminate phase, shorthand C4AF is not well defined. In other systems like in soils or sediments iron phases play a key role in the fixat...

Sub-wavelength nanostructured systems with tunable electromagnetic properties, such as hyperbolic metamaterials (HMMs), provide a useful platform to tailor spontaneous emission processes. Here, we investigate system comprising Eu3+(NO3)3·6H2O nanocrystals on an HMM structure featuring hexagonal array of Ag nanowires in porous Al2O3 matrix. The HMM-coupled Eu3+ ions exhibit up 2.4 fold increase ...

The present study investigates the effect of β-hemihydrate gypsum (HG) dosages on mechanical and microstructural performance cemented paste backfill (CPB) produced from sulphide-rich mine tailings using NaOH-activated slag (NAS) as major binder. X-ray diffraction (XRD), scanning electron microscopy (SEM) mercury intrusion porosimetry (MIP) analyses were carried out to elucidate mineralogical co...

The major hydraulic phase in all the calcium aluminate cements including ciment fondue is CA (CaAl2O4). Once hydrated, it starts to form the hexagonal crystals of CAH10 and C2AH8 that depending on the time and temperature of hydration convert to the cubic crystals of C3AH6 and AH3. The nature, sequence, ...

We explored the B-C-O system at pressures in the range 0-50 GPa by ab initio variable-composition evolutionary simulations in the hope of discovering new stable superhard materials. A new tetragonal thermodynamically stable phase B4CO4, space group I4[combining macron], and two low-enthalpy metastable compounds (B6C2O5, B2CO2) have been discovered. Computed phonons and elastic constants show th...

Most of calcium silicate hydrate or calcium aluminosilicate hydrate, CS(A)H, and related phases are relevant to Cement industry and have potential as geothermal well sealants as well as autoclaved construction materials. The CS(A)H system is highly complex and is comprised of crystalline to amorphous phases with variable composition that build up a wide family of phases, which are interesting f...

A first-principles study of the vibrational modes of PbTiO3 in the ferroelectric tetragonal phase has been performed at all the main symmetry points of the Brillouin zone ~BZ!. The calculations use the local-density approximation and ultrasoft pseudopotentials with a plane-wave basis, and reproduce well the available experimental information on the modes at the G point, including the LO-TO spli...

The thermal performance of a phase change energy storage building envelope with the ventilated cavity was evaluated. CaCl2·6H2O-Mg(NO3)2·6H2O/expanded graphite (EG) employed to combined for year-round management. consumption caused by under different influence parameters evaluated numerically. results indicated that CaCl2·6H2O-8wt %Mg(NO3)2·6H2O/EG should be installed on south wall heating seas...

The purpose of this study was to use a tape casting technique to develop an Al2O3 fiber-reinforced Al2O3-based ceramic material (Al2O3-fiber/Al2O3 composite) into a new type of dental ceramic. The Al2O3-based ceramic used a matrix consisting of 60 wt% Al2O3 powder and 40 wt% SiO2-B2O3 powder. The prepreg sheets of Al2O3-fiber/Al2O3 composite (in which uniaxially aligned Al2O3 fibers were infilt...