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The effect of barium on the formation, structure and phase transition of tricalcium silicate (C3S) has been studied by X-ray powder diffraction combined with Rietveld method, Differential scanning calorimetry and Fourier transform infrared spectroscopy. The results showed that the low contents of barium was favorable the formation of C3S with up to 1.5% BaO. Higher amounts of BaO inhibited the C3S crystallization and lead to preferential formation of dicalcium silicate solid solution. Three triclinic forms T1, T2 and T3 of C3S were stabilized. The lattice parameters changed linearly to the barium content, however the discontinuity appeared at the phase transformation boundary, which follows the Vegards law. The crystallographic structure of T1 and T2 was similar to that of T3. The SiO44- tetrahedra were distorted in T1 and T2, while that was approximately regular tetrahedron in T3. The phase transitions of C3S were influenced by the incorporation of barium. It was believed that the stabilization of high temperature polymorphs of C3S was related to the lattice distortion caused by ionic substitution.

The paper analyses the structural peculiarity and design methods of the adjustable heat pump, bring forward a new project which used adjustable heat pump system for paper machine dryers. The system can enhance the steam’s function, accelerate the speed and economize the energy.

TEMPO-oxidized cellulose nanofibers (TOCNs) were used as nanofillers in this work. Composite nanofibers of polyvinyl alcohol (PVA)/waterborne polyurethane (WPU) reinforced with TOCNs were produced by electrospinning. The reinforcing capability of TOCNs was investigated by tensile tests. Scanning electron microscopy (SEM), X-ray diffraction, and thermogravimetry analyses were also carried out in order to characterize the appearance, crystallinity, and reinforcing effect of the cellulose nanofibers. SEM results showed that PVA/WPU/TOCNs composite nanofibers presented a highly homogeneous dispersion of TOCNs. The reinforced composites had about 44% increase in their mechanical properties with addition of only 5 wt % of TOCNs while about 42% decrease in elongation at break. The TOCNs reinforced composite nanofibers were more thermally stable than pure PVA/WPU nanofibers. The development of crystalline structure in the composite fibers was observed by XRD. Since PVA, WPU, and TOCNs are hydrophilic, non-toxic, and biocompatible, and therefore, these nanocomposite nanofibers could be used for tissue scaffolding, filtration materials, and medical industries as wound dressing materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41051.