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[en] The authors conducted the research to identify a mechanism for polyphenylsiloxane inclusion into a cement composition and proposed an easier way to introduce an organosilicon modifier into cement clinker. In particular, the authors found out that polyphenylsiloxane reacts with portland clinker minerals during mechanochemical activation. The interreaction products were identified and studied. The authors synthesized the polymetallorganosiloxane compounds similar to the products obtained due to the reaction between polyphenylsiloxane and cement clinker at mechanochemical activation. It was demonstrated that polyphenylsiloxane reacting with calcium oxide and calcium carbonate results in polycalciumphenylsiloxane obtaining. Further, the article presents the comparative study of the physical and chemical and resistance characteristics of the cement compositions modified with polyphenylsiloxane and polycalciumphenylsiloxane. It was demonstrated that polycalciumphenylsiloxane improves cement composition freeze resistance as well as bending and compression resistance better than polyphenylsiloxane. (paper)
[en] In this study, we investigated the preparation process of lithium metal using a novel carbothermic reduction process. Herein, thermodynamic calculations and experimental research methods were used to investigate the novel carbothermal reduction process of LiAlO2 for preparing lithium metal in a vacuum. The results suggest that the temperature of the chemical reaction can be significantly reduced by reducing the pressure in the system. When the system pressure was 10 Pa, the reduction temperature, reduction time, molar ratio of C/LiAlO2, and reduction rate were 1623 K, 120 min, 0.9, and 79.01%, respectively. Furthermore, the lithium content in the reduction residue was 2.1 wt%, suggesting the presence of the LiAl5O8 phase. Under these conditions, when 20% CaO was added, the reduction rate of lithium increased to 99.38%, and the lithium in the reduction residue takes the form of CaAl2O4. This shows that CaO, as an additive, can promote reduction, compromise the effect of LiAl5O8, and increase the reduction rate of lithium. (paper)
[en] ZrO2:CaO and ZrO2:Y2O3 systems have been examined for possible ordered compounds. Fluorite related ordered compounds CaZr4O9 and Zr3Y4O12 have been successfully prepared and identified. While it is believed that the former is monoclinic with a = 17.813 +- 0.005A, b = 14.612 +- .004A, c = 12.065 +- .003A and β = 119.5 +- .020 and isostructural with CaHf4O9, the latter appears to be isostructural with M7O12 type of compounds with a = 9.723 +- .001A and c = 9.090 +- 0.002A, which is formed commonly in compounds containing tri and tetravalent cations and is characterized by a chain oxygen vacancy along a  of the original fluorite. No other fluorite related ordered compound could be detected in these systems
[en] A semi-quantitative X-ray diffractometric study, compared to CaO analysis, for the evaluation of the percentage of amphibole present in cosmetic talcs is presented. Scanning electron images show these needle-like minerals togheter with talc; these minerals can cause from simple allergies to serious health problems to the human being. (Author)
[pt]Apresenta-se um metodo semi-quantitativo de difratometria em raios-X comparado com a analise do CaO, para a avaliacao da percentagem de anfibolio presente nos talcos cosmeticos. (A.R.H.)
[en] The composition and phase equilibrii of the system CaO-VOsub(1.5)-VOsub(2) have been studied. The order of transformation steps during oxidation in air of individual compounds Casub(0.15)VOsub(2) and CaV2O4 have been established by X-ray analysis, DTA, and infrared spectroscopy
[en] Over the last few years, "4"7Sc has attracted significant attention for potential use in cancer theranostics due to its favorable nuclear decay characteristics (t_1_/_2 = 3.35 d; average β energy, 162 keV; Eγ, 159 keV). No-carrier-added (NCA) "4"7Sc can be produced via the "4"6Ca(n,γ)→"4"7Sc reaction in a nuclear reactor. For this purpose, 1 mg of CaO (98 % enrichment of "4"6Ca) target was irradiated for 7 d at a flux of 1 × 10"1"4 n.cm"-"2.s"-"1 at the Dhruva reactor of our research centre. The irradiated target was dissolved in 5 ml of 1 M HCl inside a lead shielded facility. The resultant solution was evaporated to near dryness, reconstituted in 20 ml of 0.15 M lithium citrate solution and transferred to the electrochemical cell. The electrochemical separation involved selective amalgamation of Ca from Ca/Sc mixture into mercury-pool cathode. The influence of different experimental parameters (such as applied potential, pH of the electrolyte, time of electrolysis and amount of Ca"2"+ ions in the electrolyte) on the separation process was investigated and optimized for the quantitative electroamalgamation of Ca
[en] When optical active ions are doped into a host, two different methods for determining the composition ratio are usually employed. In one method, the condition for the number of cations was satisfied, in the other method, the condition for the amount of cation charge was satisfied. Until now the two different methods have been adapted, although the local sites of the dopant ions in the host are well known. By comparing the luminescence properties of samples synthesized with different compositions, we observed that the condition for the amount of cation charge (charge compensation) played a key role in the preparation of phosphor materials by enhancing both their crystallinity and covalency. These results demonstrate that the charge compensation is significantly effective in enhancing the emission intensity of the phosphor. Also, when Bi3+ ions are incorporated into the CaMoO4:Eu3+ phosphor, they break the symmetry of the crystal field around the Eu3+ ions and result in an enhancement of the PL intensity by a factors of 1.7 ∼ 2.7 (condition for the number of cations) and 6.2 (condition of charge compensation).
[en] El-Sibaiya phosphorites represent a part of the Middle East to North Africa phosphogenic province. They encountered in the Gabal (G.) Duwi Formation of Late Cretaceous to Paleogene age. The studied samples have been collected from the eastern and western sides of the Nile River. Major elemental analysis of the collected samples declared positive correlations between P2 O5 an d CaO and F. These correlations indicate that these elements are contained in the apatite phase. On the other hand, P2O5 shows negative correlations with other major elements such as Al2O3 , SiO2, Fe2O3 and MgO. Some trace elements such Cr, Sr and V s how positive correlation with P2O5 . The average of the total rare earth elements (∑REEs) in the studied phosphorites is 262 ppm. Chondrite-normalized patterns of ∑REEs of the studied phosphorites show a good coherence with the world average of shale suggesting that ∑REEs in the studied phosphorites were derived from the associated clastic debris through the diagenetic remobilization. The week negative Ce and Eu anomaly of the studied samples and the marked enrichment in LREEs emphasize that the studied phosphorites subjected to a later post-depositional modification. Laser ablation analysis showed that apatite mineral of the studied phosphorites is enriched in some elements such as Ca, F, Cr, Sr, V, Zn, Ba and REEs. This explains the major role of substitution processes of these elements within apatite lattice. The uranium average in El-Sibaiya East phosphorites is 81.6 ppm, while in El-Sibaiya West is 51.1 ppm. Apatite minerals play an important role in the accumulation of U within the studied phosphorites
[en] Detection of latent fingerprint was performed using zinc oxide nanoparticles which were produced by simple and efficient method in aqueous media from zinc nitrate. Synthesized ZnO nanoparticles were characterized by XRD, SEM and AFM for ZnO purification and particle size examination. In this paper an effort has been made to compare the results of using ZnO nanoparticles and conventional fingerprint powders such as ZnO bulk powder, CaO, TiO2, printer toner powder and graphite. Fingerprints on different materials were also examined by the use of ZnO and Graphite powder, which is currently used in the Central Intelligence Department of Myanmar Police Force.From this research, it was observed that zinc oxide nanoparticles powder produced a much clearer picture of the fingerprints, compared to conventional powders and it has very good quality at sticking to the fingerprint residue but not to the background surface.
[en] Research activities into the physical properties of metals and ceramics at Lawrence Berkeley Laboratory during 1976 are reported. Topics covered include: high field superconductivity; microstructure and mechanical behavior of ceramics, glass-metal, and ceramic-metal systems; high temperature reactions; relation of microstructure to properties in ceramics; and structure and properties of carbon materials and composite materials