Papers by Keyword: Minerals

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Authors: Shi Chun Mu, M. Pan, Run Zhang Yuan
Abstract: Some minerals were considered to store hydrogen on the basis of their porous crystal structure. Besides of crystal graphite and zeolite, some natural clay minerals such as palygorskite-sepiolite minerals with nano-scale channels and polar surface can also store hydrogen. The hydrogen storage mechanism of porous minerals was discussed. The experimental results showed a potential application of palygorskite-sepiolite minerals as the media of hydrogen storage.
2441
Authors: Y. Kabalov, E. Sokolova, V. Gorbatova, J. Schneider, A. Konev
994
Authors: Sandra Piazolo, David J. Prior, M.D. Holness, Andreas O. Harstad
Abstract: Annealing is an important mechanism of microstructural modification both in rocks and metals. In order to relate directly changes in crystallographic orientation to migrating boundaries the researcher has the option to investigate either samples where the grain boundary motion can be directly tracked or a series of samples exhibiting successively higher degrees of annealing. Here we present results from rock samples collected from two well characterised contact aureoles (a volume of rock heated by the intrusion of a melt in its vicinity): One quartz sample in which patterns revealed by Cathodoluminescence (CL) indicate the movement of grain boundaries and a series of calcite samples of known temperature history. Electron backscatter diffraction (EBSD) analysis is used to link the movement of grain, twin boundaries and substructures with the crystallographic orientation / misorientation of a respective boundary. Results from the quartz bearing rock show: (a) propagation of substructures and twin boundaries in swept areas both parallel and at an angle to the growth direction, (b) development of slightly different crystallographic orientations and new twin boundaries at both the growth interfaces and within the swept area, and (c) a gradual change in crystallographic orientation in the direction of growth. Observations are compatible with a growth mechanism where single atoms are attached and detached both at random and at preferential sites i.e. crystallographically controlled sites or kinks in boundary ledges. Strain fields caused by defects and/or trace element incorporation may facilitate nucleation sites for new crystallographic orientations at distinct growth interfaces but also at continuously migrating boundaries. Calcite samples show with increasing duration and temperature of annealing: (a) systematic decrease of the relative frequency of low angle grain boundaries (gbs), (b) decrease in lattice distortion within grains, (c) development of distinct subgrains with little internal lattice distortion, (d) change in lobateness of gbs and frequency of facet parallel gbs and (e) change in position of second phase particles. These observations point to an increasing influence of grain boundary anisotropy with increasing annealing temperature, while at the same time the influence of second phase particles and subtle driving-force variations decrease. This study illustrates the usefulness of using samples from natural laboratories and combining different analysis techniques in microprocess analysis.
333
Authors: Johar Banjuraizah, Mohamad Hasmaliza, Zainal Arifin Ahmad
Abstract: α Cordierite is very important phase in MgO-Al2O3-SiO2 system because of their very outstanding thermal, chemical and electrical properties. In this presents study non-stoichiometry cordierite (MgO:Al2O3:SiO2 = 3:1.5:5) using 2 different initial raw materials ( (i)mixture of pure oxide, and ii) mainly mixture of minerals) were fabricated and compared in terms of phase transformation and physical properties. Cordierite was prepared by glass method at low melting temperature (1350oC). Low melting temperature has resulted in partly crystalline glass which has possesses higher hardness, required longer milling time and result in contamination from grinding media. However, α-cordierite has successfully crystallized and fully densified at 850oC/2h. Activation energy for densification was investigated from thermal expansion coefficient (TCE) results. Other properties that were discussed included thermal properties using DTA/TGA.
196
Authors: Yu Wei Feng, Li Zhen Ma, Yu Can Du, San Hong Fan, Rui Tong Dai
Abstract: Crude protein, total lipids, moisture, total ashes and selected mineral (Ca, Mg, Fe, Zn, Cu, Mn) content, fatty acid and amino acid composition were determined in the muscle tissue of three widely consumed fish species (sardine, anchovy and mackerel) obtained from Quanzhou of China. All fish species were high in protein (21.46%~22.75%), with total lipid and moisture content varied from 2.24% to 8.23% and from 69.7% to 74.9%, respectively, depending on the species. Total ash content range from 1.25%~1.63% but macrominerals content varied considerably with Mg content ranged from 470.24mg/100g to 687.45mg/100g and Ca levels ranged from 16.40mg/100g~109.22 mg/100g depending on the species. The most abundant microminerals were Fe and Zn followed by Cu and Mn. In all the three species, palmitic acid (28.44%~30.62%) was the predominant saturated fatty acid. Oleic acid (11.23%~22.15%) was the most abundant monounsaturated fatty acid. DHA was the main polyunsaturated fatty acids, followed by EPA. Sardine had the highest DHA (12.74%). Amino acid compositions were similar for the three species which were high in glutamate, lysine, leucine and aspartate and low in cysteine. Almost all amino acids content of anchovy were higher than other two species.
900
Authors: Run Chen, Yong Qin
Abstract: CO2 storage in coal seam is the important way of reducing CO2 emission into atmosphere and enhancing coal-bed methane (CBM) recovery. This paper based upon the results of CO2 storage in coal seam in theoretical research and demonstration project, analyzed the mechanism of CO2 storage in coal seam, and recognized that the process is a complex process from a single physical process to physical, chemical, and microbial effect process. The paper also summarized the fluid-solid coupling actions between H2O-CO2 and minerals in coal seam and its effect on coal reservoir characteristics. It is considered that after H2O-CO2 action, the components of coal petrography changed. At the same time, there has been marked change in coal physical properties: the porosity enhanced, mechanics property reduced, and the changed of adsorptivity and permeability need further researches. This paper can guide the prediction storage ability and assessment the safety of CO2 in coal seam.
2283
Authors: M. Mohsen, Ehsan. A.H. Gomaa, H. Schut, A. van Veen
402
Authors: Stanislav V. Naumov, Michael N. Ignatov, Anna M. Ignatova, Arseny O. Artemov
Abstract: Slag bases for welding materials have been developed from mineral raw materials and man–made mineral formations of the Urals. Successful comprehensive studies and tests of fused fluxes and also of weld metal and weld joints obtained by these welding materials have been carried out. It has been clearly established that the obtained weld metal has low content of harmful impurities ([S] is as low as 0.01 wt%) due to the use of the electric arc furnace method, purity of the feedstock minerals and technogenic raw materials and physicochemical reactions during the welding process.
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