andalusite, kyanite and sillimanite occur in well-defined zones in the ardara aureole, nwireland. temperature and pressure conditions of the al2sio5-bearing pelites in this aureole wereestimated using ten different calibrations of garnet-biotite thermometry and five calibrations of garnetplagioclase-al2sio5-quartz barometry. the different calibrations provide different estimates oftemperature a...

Aluminium, the third most abundant element in the earth’s crust, occurs in nature in combination with silicon and oxygen (i.e. as aluminium silicate). When subject to tropical weathering, aluminium silicate may react to form aluminium hydroxide. Rock containing high concentrations of aluminium hydroxide is called bauxite. This rock is the usual starting material for the production of aluminium....

The objective of the present study was to investigate the use of propranolol-magnesium aluminium silicate intercalated complexes as drug reservoirs in hydroxypropylmethylcellulose tablets. The matrix tablets containing the complexes were prepared and characterised with respect to propranolol release and were subsequently compared with those loading propranolol or a propranolol-magnesium alumini...

This article reviews the analytical methods for crystalline silica polymorphs and summarizes promising techniques for compliance with health-related regulations. X-ray diffraction analysis appears to be the most promising method of determining quartz and cristobalite content at this threshold in many bulk mineral and chemical systems. Other analytical techniques can be used in some mineral and ...

With the increasing demands of high surface irregularities and machining of composites, conventional machining processes are now being replaced by high speed Computer Numerical Control (CNC) machines. In this paper aluminium silicate made from alloying aluminium and silicon oxide made from rice husk are used. The machining of the alloy on CNC machine is carried out. In addition to speed, feed a...

Silicon isotope fractionation factors for mantle silicate minerals, including olivine, wadsleyite, ringwoodite, pyroxenes, garnet (pyrope), majorite, and Mg-perovskite, are calculated using density functional theory. Our results show that equilibrium fractionations of Si isotopes are negligible among pyroxenes, olivine, and pyrope, but are significant between olivine and its polymorphs (wadsley...

Introduction Elemental beryllium is a steel gray appearing alkaline earth metal with properties like brittleness and high rigidity being the lightest among metals. The majority of beryllium is found in minerals and soils rather than in its elemental form. Beryllium is found in about 30 different mineral species like different compounds including aluminium e.g. Beryl (beryllium aluminium silicate).

A molecular dynamics study of the aluminosilicate chains structure in Al-rich calcium silicate hydrated (C-S-H) gels A molecular dynamics study of the aluminosilicate chains structure in Al-rich calcium silicate hydrated (C-S-H) gels. Calcium silicate hydrated (C-S-H) gel is the principal binding phase of the cement paste and responsible for its strength. It is basically composed of silicate ch...

Glasses and glass-ceramics (GCs) used for sealing, coating and high voltage applications belong to a special class of materials in which among other requirements, matching of thermal expansion coefficient with that of metal as closely as possible up to set temperature is an important consideration. In this paper I shall concentrate on some indigenous efforts carried out in my laboratory on the ...

It is a well-known fact that the spectra of oxygen-rich circumstellar dust envelopes around evolved stars show great diversity, especially in the 10 μm silicate band profiles, but also in the longer infrared wavelength range covered by ISO. This supports earlier conclusions that the concept of a universal cosmic silicate is inadequate and that it is reasonable to consider a wider variety of pos...