Sustainable Development of the Cement Industry and Blended Cements to Meet Ecological Challenges

The world production of cement has greatly increased in the past 10 years. This trend is the most significant factor affecting technological development and the updating of manufacturing facilities in the cement industry. Existing technology for the production of cement clinker is ecologically damaging; it consumes much energy and natural resources and also emits pollutants. A new approach to the production of blended or high-volume mineral additive (HVMA) cement helps to improve its ecological compatibility. HVMA cement technology is based on the intergrinding of portland cement clinker, gypsum, mineral additives, and a special complex admixture. This new method increases the compressive strength of ordinary cement, improves durability of the cementbased materials, and -at the same time -uses inexpensive natural mineral additives or industrial by-products. This improvement leads to a reduction of energy consumption per unit of the cement produced. Higher strength, better durability, reduction of pollution at the clinker production stage, and decrease of landfill area occupied by industrial by-products, all provide ecological advantages for HVMA cement

The low-mass stellar population in the young cluster Tr37: Disk evolution, accretion, and environment

We present a study of accretion and protoplanetary disks around M-type stars in the 4 Myr-old cluster Tr37. With a well-studied solar-type population, Tr37 is a benchmark for disk evolution. We used low-resolution spectroscopy to identify 141 members (78 new) and 64 probable members, mostly M-type stars. H\alpha\ emission provides information about accretion. Optical, 2MASS, Spitzer, and WISE data are used to trace the SEDs. We construct radiative transfer models to explore the structures of full-disks, pre-transition, transition, and dust-depleted disks. Including the new and previously known members, we confirm that a substantial fraction (~2/5) of disks show signs of evolution, either as radial dust evolution (transition/pre-transition disks) or as a more global evolution (low small-dust masses, dust settling, and weak/absent accretion signatures). Accretion is strongly dependent on the SED type. About half of the transition objects are consistent with no accretion, and dust-depleted disks have weak (or undetectable) accretion signatures, especially among M-type stars. The analysis of accretion and disk structure suggests a parallel evolution of dust and gas. We find several distinct classes of evolved disks, based on SED type and accretion, pointing to different disk dispersal mechanisms and probably different evolutionary paths. Dust depletion and opening of inner holes appear to be independent processes: most transition disks are not dust-depleted, and most dust-depleted disks do not require inner holes. The differences in disk structure between M-type and solar-type stars in Tr37 (4 Myr) are not as remarkable as in the young, sparse, Coronet cluster (1-2 Myr), suggesting that other factors, like the environment/interactions, are likely to play a role in the disk evolution and dispersal. Finally, we also find some evidence of clumpy star formation or mini-clusters within Tr37.Comment: 21 pages, 16 figures, plus appendix with tables and figures. Accepted by A&

Assessment of the quantitative accuracy of Rietveld/XRD analysis of crystalline and amorphous phases in fly ash

An internal standard method based on Rietveld/XRD whole-pattern fitting analysis of fly ash is used to assess the quantitative accuracy to determine its crystalline and amorphous phases under various conditions such as internal standards (types, SiO2 or Al2O3 and dosages, 10–50%), incident X-rays (laboratory or synchrotron) and refinement software (GSAS or TOPAS). The results reveal that the quantitative stability is quite sensible to minor phases, identical to the internal standard, in fly ash. Errors positively correlate with the weight fraction of that minor phase and negatively correlate with the dosage of an internal standard and amorphous phase content in fly ash. The original equation for the amorphous phase calculation is not applicable for a case with a higher inherent quartz content (>2.5%) in fly ash while the dosages of the internal standard is lower than 20%. The original equation is modified as proposed. Based on it, the quantitative results of five different patterns report a good reproducibility with the arithmetic mean errors and the standard errors of identified main phases of around 1%.The access to the beamline BL14B1 facilities at the SSRF is appreciated and the support of SSRF management, User Office and beamline staff is highly appreciated. This Research is supported by the National Natural Science Foundation of China (No. 51602126), the National Key Research and Development Plan of China (2016YFB0303505) and the Program for Scientic Research Innovation Team in Colleges and Universities of Shandong Province

Combined investigation of collective amplitude and phase modes in a quasi-one-dimensional charge-density-wave system over a wide spectral range

We investigate experimentally both the amplitude and phase channels of the collective modes in the quasi-1D charge-density-wave (CDW) system, K0.3MoO3, by combining (i) optical impulsive-Raman pump-probe and (ii) terahertz time-domain spectroscopy (THz-TDS), with high resolution and a detailed analysis of the full complex-valued spectra in both cases. This allows an unequivocal assignment of the observed bands to CDW modes across the THz range up to 9 THz. We revise and extend a time-dependent Ginzburg-Landau model to account for the observed temperature dependence of the modes, where the combination of both amplitude and phase modes allows one to robustly determine the bare-phonon and electron-phonon coupling parameters. While the coupling is indeed strongest for the lowest-energy phonon, dropping sharply for the immediately subsequent phonons, it grows back significantly for the higher-energy phonons, demonstrating their important role in driving the CDW formation. We also include a reassessment of our previous analysis of the lowest-lying phase modes, whereby assuming weaker electronic damping for the phase channel results in a qualitative picture more consistent with quantum-mechanical treatments of the collective modes, with a strongly coupled amplitudon and phason as the lowest modes

From superhydrophilicity to superhydrophobicity: high-resolution neutron imaging and modeling of water imbibition through porous surfaces treated with engineered nano-coatings

This paper reports on a superhydrophilic to superhydrophobic transformation of TiO2 nanoparticles doped zinc phosphate coating systems when a hydrophobic agent is applied. The objective of the reported research was to demonstrate the feasibility of a neutron imaging technique for evaluating the performance of the proposed nano-coating system and reveal the differences in water ingress mechanisms which are specific to plain, superhydrophilic, overhydrophobic, and superhydrophobic specimens. The engineered nano-coatings were designed to improve hydrophobic response with inducing the required roughness pattern and introducing the photocatalytic performance. The effectiveness of the coatings was assessed using high-resolution neutron imaging (HR-NI), SEM, CLSM, and XRD techniques. High-resolution neutron imaging revealed that the superhydrophobic coating effectively prevents water ingress into the porous ceramic substrate, whereas water imbibition was observed for superhydrophilic coating during the test duration. The moisture transport kinetics was modeled based on the Richards equation for plain ceramic and superhydrophilic specimens using obtained penetration depth values from HR-NI. SEM, CLSM, and XRD studies confirm the desired TiO2-doped zinc phosphate coatings with increased surface roughness, photocatalytic reactivity, and chemical bonding. The research results demonstrated that a two-layer superhydrophobic system is capable of creating effective water barriers on the surface with contact angles of 153°, which remained effective even after surface damage

Enhanced UV Light-Emission of Zinc-Phosphate-Hydrate Hydrothermally-Grown on Cu Metal Substrates for Opto-Electronic Applications

In the present study, polycrystalline films of layered zinc phosphate hydrate are produced by a facile, low-temperature single-step hydrothermal fabrication method on top of Cu metal substrates. Despite containing structural water, the as-grown films remain crystalline, chemically stable, and electrically conductive. The photoluminescence spectrum obtained at room-temperature reveals the presence of a spectrally narrow, high-intensity ultraviolet band that consists of two Gaussian peaks at ≈377 and 383 nm and a UV-to-visible peak emission intensity ratio of ≈5.3. The electrical charge-transport properties remain Ohmic for electric fields of up to ≈2 kV m−1 and temperature (T) range of ≈223–368 K. The electrical conductivity is further found to vary exponentially with the inverse temperature, and the thermal activation energy, Ea is 285 ± 8 meV. A moderate UV-vis photoconduction effect is registered and assigned to light-assisted electronic transitions that involve near-band edge defect states. This study can potentially open a door to the engineering and deployment of water-based compounds with advanced, semiconducting-like attributes in short-wavelength opto-electronic devices

Desempeño de compuestos con fibras de alcohol polivinílico y nano-fibras/tubos de carbono

[ES] La adición de fibras en morteros compuestos a base de cemento portland es una práctica común para la prevención de la formación de grietas y para incrementar la resistencia a la flexión. En esta investigación, se estudiarán morteros Compuestos Fibro-Reforzados (CFR) con Fibras de Alcohol Polivinílico (FAP), reforzadas con Nanofibras de Carbono (NFC) o Nanotubos de Carbono (NTC) para el desarrollo de sistemas de Supervisión de la Salud Estructural (SSE). Los especímenes fabricados fueron ensayados a la resistencia a la flexión, absorción de agua y a la conductividad eléctrica en agua o en solución con NaCl. Los resultados demostraron una dependencia de los especímenes al tipo de solución a la cual fueron expuestos. Se demostró que la sensitividad a la deformación y a la solución de NaCl puede ser incrementada por la adición de los NTC. Los resultados en el incremento de la conductividad con los compuestos de NTC pueden ser escalables para las aplicaciones de monitoreo no-destructivo en estructuras de autodetección de concreto que requieran una mejora integral bajo las cargas aplicadas y estabilidad en ambientes deletéreos.Hoheneder, J.; Flores Vivian, I.; Vergara Alvarez, L.; Sobolev, K. (2018). Desempeño de compuestos con fibras de alcohol polivinílico y nano-fibras/tubos de carbono. En HAC 2018. V Congreso Iberoamericano de hormigón autocompactable y hormigones especiales. Editorial Universitat Politècnica de València. 321-327. https://doi.org/10.4995/HAC2018.2018.6473OCS32132