With the assistance of heat treatment, forsterite (Mg 2SiO 4) powder was successfully synthesized using talc and magnesium oxide as the basic starting materials. Sintering behavior and mechanical properties were evaluated upon sintering... more
With the assistance of heat treatment, forsterite (Mg 2SiO 4) powder was successfully synthesized using talc and magnesium oxide as the basic starting materials. Sintering behavior and mechanical properties were evaluated upon sintering the synthesized forsterite compacts from 1200 °C to 1500 °C. Forsterite phase without any secondary phase were observed at all sintering temperatures analyzed by X-ray diffractometer (XRD). Results also showed that relative density of 90.7% was obtained at sintering temperature of 1500 °C. Optimal fracture toughness (4.88 MPa.m 1/2) and Vickers micro-hardness (7.11 GPa) were achieved when sintered at 1400 °C.
The notch root elasto-plastic strains of circumferentially grooved round specimen of cast magnesium WE43-T6 were experimentally measured using the electronic speckle pattern interferometry (ESPI) and numerically evaluated using the finite... more
The notch root elasto-plastic strains of circumferentially grooved round specimen of cast magnesium WE43-T6 were experimentally measured using the electronic speckle pattern interferometry (ESPI) and numerically evaluated using the finite element analysis (FEA). The specimens have notch radii of 1.6 mm and 0.8 mm and an opening angle of 60°. The technique of ESPI showed its accuracy in measuring three-dimensional surface deformations on large negatively curved manifolds. The measured nominal stress for rupture is well beyond the ultimate strength, suggesting the existence of significant biaxial stress at the notch root region. The ESPI-based strains on the notch tips were shown to be in agreement with those evaluated by the FEA. The FEA also showed that the maximum elastic strain is shifted away from the notch root surface as the plastic strain is predominant.
In order to test whether or not methane producing archaea may survive solely on the products forming through the hydration of olivine, we have analyzed the products formed from the low temperature incubation of natural forsterite sand in... more
In order to test whether or not methane producing archaea may survive solely on the products forming through the hydration of olivine, we have analyzed the products formed from the low temperature incubation of natural forsterite sand in buffered water. Already after one month of incubation, the molecular hydrogen concentration was high enough to theoretically sustain the survival of methanogenic archaea at temperatures above 30° C. Also, many important trace elements were present as well as a low enough redox potential. Introduction Hydrocarbons are known to be formed through the reduction of CO2 by H2 in the so called Fischer-Tropsch Type or Sabatier reaction in hydrothermal systems (Charlou 2002; Holm 1998; Rushdi A. 2001), but the temperatures used are often higher than at least 100° C. (McCollom 2009). Hydrocarbon and/or hydrogen formation in lower temperature environments would expand the plausible sites for the existence and growth of microbial communities and possibly also t...
In the present study, phase pure forsterite was obtained in sintered bodies from powder mixtures that did not undergo a heat treatment process prior to sintering. This is contrary to the practice reported in the literature where the... more
In the present study, phase pure forsterite was obtained in sintered bodies from powder mixtures that did not undergo a heat treatment process prior to sintering. This is contrary to the practice reported in the literature where the powder mixture is normally subjected to a heat treatment at about 1200 °C prior to sintering process. The present results revealed that pure forsterite could be obtained after sintering the powder mixture above 1300 °C. The study found that the mechanical properties of forsterite increased with increasing sintering temperature. A maximum Vickers hardness and fracture toughness of 7.68 GPa and 5.16 MPam1/2 were measured for samples sintered at 1500 °C.
"The current study is to examine the effect of ultrasonication on the synthesis of forsterite (Mg2SiO4) powder. Ultrasonication and ball milling were performed using talc and magnesium oxide as starting precursors, followed by heat... more
"The current study is to examine the effect of ultrasonication on the synthesis of forsterite (Mg2SiO4) powder. Ultrasonication and ball milling were performed using talc and magnesium oxide as starting precursors, followed by heat treatment to obtain forsterite. The X-ray diffraction results of the powders heat treated at 1200 °C showed that the 2 hours ultrasonication followed by 3 hours ball milling was beneficial in retaining the forsterite phase in the matrix. The results were similar to ball milling for 10 hours prior to heat treatment. The derived powders also exhibited very fine crystallite size in the range of 28 to 35 nm thus indicating the viability of using ultrasonication as part of the processing steps in the synthesizing of forsterite ceramics.
Porous silica materials are widely known for various applications from adsorbents, catalysis, and as template to metal oxide. In recent years, ordered mesoporous silica xerogels had gained considerable attention in various field because... more
Porous silica materials are widely known for various applications from adsorbents, catalysis, and as template to metal oxide. In recent years, ordered mesoporous silica xerogels had gained considerable attention in various field because of the reduced production cost and improved properties. Recently, a low-cost attempt on producing nanosized perovskite, spinels, and mesoporous carbon via silica xerogel templating route, where the silica xerogel used had the structural characteristics similar to mesoporous silica materials, is reported in this chapter. The chapter focuses on the attempt to produce silica xerogels with similar properties as MCM type silica materials using renewable resources of palm oil derived hydrocarbons in nanometer size oil-in-water droplets emulsion. To study the application of the silica xerogels as silica support materials, “one-pot” functionalization method using phenol red were carried out and the resulting materials were characterized accordingly. Nanoporous silica xerogels with high surface area, pore volume, and fine spherical morphology with particle size from ca. 50 nm were successfully synthesized using the palm oil derivatives of fatty alcohols employing acoustic emulsification. The oil droplets in the presence of co-solvent such as short-chain alcohols to act as dispersant behaved as template where the hydrolysis and condensation-polymerization of silica could take place.
"In the present study, phase pure forsterite was obtained in sintered bodies from powder mixtures that did not undergo a heat treatment process prior to sintering. This is contrary to the practice reported in the literature where the... more
"In the present study, phase pure forsterite was obtained in sintered bodies from powder mixtures that did not undergo a heat treatment process prior to sintering. This is contrary to the practice reported in the literature where the powder mixture is normally subjected to a heat treatment at about 1200 °C prior to sintering process. The present results revealed that pure forsterite could be obtained after sintering the powder mixture above 1300 °C. The study found that the mechanical properties of forsterite increased with increasing sintering temperature. A maximum Vickers hardness and fracture toughness of 7.68 GPa and 5.16 MPam1/2 were measured for samples sintered at 1500 °C.
