Papers by Keyword: Garnet

Abstract: The aim of the work was to characterize the clay from Amuda-Isuochi, Abia state Nigeria. Preliminary research works on the area is scanty. The characterization involved chemical and elemental analyses, X-ray diffraction, specific surface area analysis, thermal analyses (TGA, DTA) and particle size distribution. The results showed that the clay is kaolin. Specific surface area of 251m²/g was observed, with average particle size of 84.67d.nm and polydispersity index of 0.203. The sample will find applications in oil and gas industry as lost circulation control material and for manufacture of proppants for hydraulic fracturing activities. Similarly, it can be used as an adsorbent and has potential applications for ceramic tile, paper, paints, fibre glass and starting material for alum. The kaolin clay will also be suitable as a nano-material. The output indicates an addition to local contents for Nigeria’s industrial development.

Abstract: Li₇La₃ZrSnO₁₂ was successfully prepared by conventional solid-state synthesis. Diffraction data show that the prepared sample has a mixture of two different phases. Both phases have tetragonal crystal symmetry but two different space groups, which are I41/acd and I4/mmm. Rietveld refinements were performed by using the models of the initial structures based on Li₇La₃Zr₂O₁₂ (I41/acdz) and Li₇La₃Ce₂O₁₂ (I4/mmm). It used to quantify the ratio between those two phases by employing Relative Intensity Ratio (RIR) technique. Crystal structure analysis showed that atomic arrangement in Li₇La₃Zr₂O₁₂ (I41/acdz) has more connected 3D tunnel for Li ions migration compared to Li₇La₃Ce₂O₁₂ (I4/mmm) that only connected tunnel at the edge of unit cell. Therefore, the existence of tetragonal phase with the space group of I4/mmm may resulting low ionic conductivity of Li ions at room temperature.

Abstract: Synthesis of YSAG:Yb ceramic powders with different stoichiometry by chemical precipitation method was carried out. It has been established that scandium can replace both dodecahedral and octahedral positions of garnet. It is shown that scandium is embedded in those positions that become available to it when the YAG:Yb composition deviates from stoichiometric. Thus, scandium can compensate for the lack of one of the components of the oxide composition Y₂O₃, Yb₂O₃, and Al₂O₃ during the formation of the garnet phase.

Abstract: The article presents the results of experimental studies of differences in the nature of impact destruction of single garnet grains penetrating the target material, and presents the results of numerical simulation (modeling) of the contact interaction of an abrasive particle with a flat obstacle, which allowed determining the volume ablation of the material under the action of a single abrasive particle, and makes it possible to predict the performance of waterjet cutting.

Abstract: The Nimba Range and its western extension are located in the Nimba region on the borders of the Republic of Guinea, Liberia and Côte d'Ivoire. It is a mountainous region made up of metavolcanic and metasedimentary rocks. Metavolcanic rocks are gneisses, granites, amphibolites and quartzites, which constitute the lower part of Archean age. The upper part consists of Proterozoic rocks of metasedimentary origin. It contains important deposits of itabirites which occupy the top of the mountains and hills of the region. The petrographic study of the banded iron formations reveals the existence of silicate banded iron formations (SIF) and oxidized banded iron formations (OIF). The results of the scanning electron microscope (SEM) and metallogenic analyzes show the presence of iron minerals (magnetites, hematites, pyrites, goethites, martites and siderites). These analyzes also reveal the presence of the metamorphic index minerals associated with the banded iron formations, hence the existence of several types of ferriferous formations (silicate (SIF) and oxidized (OIF) banded iron formations). Overall, there is an increase in the degree of regional metamorphism from east to west of the Nimba region. The geochemical analysis of the banded iron formations reveals that with the exception of Na₂O, all the major elements have a negative linear correlation although dispersed with Fe₂O₃. This correlation is explained by a decrease in quartz, garnet, micas (muscovite and biotite), amphibole, pyroxene, plagioclase, titanium and phosphorus contents. Conversely, there is an increase in iron ore content: magnetites, pyrites, hematites, goethite. But the alkali content remains constant in these banded iron formations. Then, the lower the Fe₂O₃ content, the higher the FeO content, while those of SiO₂ and Al₂O₃ are constant in all of these formations in the Nimba region except in the chlorite banded iron formation where both are anticorelated. Finally, the ratio SiO₂ / Fe₂O₃ vs MgO + CaO + MnO / Fe₂O₃ of the banded iron formations of the Nimba region compared to the same formations of the whole world allows to give them Proterozoic age. Some itabirites have high levels of magnetite, hematite, and goethite (same feature as itabirites of Lac supérieur and Pic de fon) and only chlorite itabirite has a low to medium Mg-Si-BIF content.

Abstract: For the examination of freeze-thaw action, which is a durability deterioration factor of concrete, this study aimed to investigate the deterioration of concrete under the freeze-thaw condition of the high-performance concrete manufactured using both fiber and mineral admixture. After 300 freeze-thaw cycles, the relative dynamic moduli of the FA-PP-02 and SF-01 specimens were 85.7% and above 92.9%, respectively, and the compressive strengths of the FA-PP-02 and GA-Ny-03 specimens were 61% and above 83%, respectively. Among the high-performance concrete specimens, the specimen that used only Steel Fiber and the specimen that used both Garnet and Nylon showed the most outstanding freeze-thaw resistance.

Abstract: This study investigated the resistance of garnet fiber concrete (hereinafter, GFC) to magnesium sulfate. GFC was fabricated in various mix ratios using GA, nylon (Ny), polypropylene (PP), and others. Plain concrete without GA was also fabricated for comparison with GFC. The test pieces were soaked in 10% magnesium sulfate for up to 210 days to test their compressive strengths, sulfate deterioration factors (SDFs), and mass losses. It was observed from the test results that the compressive strength test pieces mixed with GA and Ny, which perform the pozzolanic reaction, had excellent performances under the influence of sulfate. The plain concrete underwent greater mass loss compared to the GFC test pieces. The test results showed that the GFC mixed with 10% GA and Ny was more resistant to magnesium sulfate than the GFC with PP.

Abstract: The previously revealed features of orientation dependences in the experimental research devoted to the channeling of ions in the multicomponent crystals of yttrium iron garnet are the reflection of the complex structure of a crystalline material. The study incorporates the development of a numerical model describing the distribution of fast ion flux in the crystal of garnet in the framework of the binary collision theory. The model is intended for the detailed elucidation of the causes of the discovered features. The calculation demonstrated the orientation dependence features similar to those established in the experiments.

Abstract: The purpose of this study is to evaluate the flexural behavior of hybrid high performance RC beams with web openings (Hy-HPRWO) that are constructed by using circle steel tube, hybrid fibers and Garnet, Fly-ash. One regular RC beam with openings (HPRC) and four Hy-HPRWO specimens were manufactured and tested under monotonic loading. It was evaluated by flexural experiment of Hy-HPRWO through comparison of failure mode, load-deflection curves, ductility and ultimate load (V_u). Test results showed that the ultimate load of the Hy-FPSC3 specimens were approximately 5.82% better than that of the HPRC, in addition their ductility behavior was 68.1% better than the HPRC.

Abstract: Eight hybrid fiber reinforced cement mortar (HFRC) mixes reinforced with Garnet-Nylon, Polypropylene (PP), Steel Fiber (SF) was tested in order to examine the effect of the W/B and replacement ratio of the Garnet-Nylon, PP, SF on the properties of matter and different material properties of HFRC. Main variables investigated were W/B and replacement ratio of the Garnet and Nylon, PP, SF. The measured material properties of fiber reinforced NS (Nylon-SF) specimens were analyzed using the two types of strength and compared with those recorded with PS (PP-SF) specimens. The flow of HFRC increased with the increase of the W/B. In addition, compressive strength, bending of HFRC was higher than those of replacement ratio of the Garnet-fibers, though the total HFRC was lower than that with NS-GA-01 specimen. For enhancing the toughness and strength of HFRC, using the GA of 5 % and Nylon of 0.1 %, PP of 0.1%, SF of 0.4% replacement ratio was more effective than using the GA of 20 % and Nylon of 0.4 %, PP of 0.4%, SF of 0.8% replacement ratio.