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Abstract

GGABBRO. Gabbro is a deep-seated and often very coarse-grained igneous rock composed of plagioclase feldspar, usually labradorite or bytownite and monoclinic pyroxene, with occasionally as accessories olivine (when it is then called olivine gabbro), biotite, magnetite, ilmenite, and hornblende. Norite is a variety of gabbro, carrying orthorhombic pyroxene, usually hypersthene instead of the monoclinic sort. Troctolite is essentially olivine and plagioclase. Quartz gabbros are known and have probably been derived from magmas somewhat oversaturated with silica. On the other hand, essexites represent gabbros whose parent magma doubtless had an insufficiency of silica resulting in the formation of nephelite. Gabbros are frequently rich in sulfides that may be of commercial value, a notable occurrence of which is at Sudbury, Canada. Here a norite carrying chalcopyrite and nickeliferous pyrrhotite forms the most important deposits of nickel known. Gold, silver and platinum are also recovered from this ore.

Automation experiments in physics laboratories

“…This work proposes a system design that operates similarly to commercial devices that automatically switches a bulb at the twilight, turning it on Figure 9 exemplifies the called civil twilight that is the first of three-twilight stage and occurs when the geometric sun centre angle relative to the horizon is between 0° and 6°. Usual outdoor activities in this period do not yet require artificial light in clear days and the higher light intensity is between 410 and 585 lux and the lower is between 2.0 and 3.5 lux [3].…”

Study of biomorphic calcium deficient hydroxyapatite fibres derived from a natural Harakeke (Phormium tenax) leaf fibre template

“…XRD analysis of the fibres heated to 120 • C, 140 • C and 160 • C, displayed the sequential diminishing peaks of MCPM, which is related to the conversion of MCPM into monetite and free phosphoric acid, however the phosphoric acid may have, itself, started to dehydrate, which resulted in its dissociation. It has been reported in the literature that when phosphoric acid is heated above 200 • C, it dehydrates and dissociates into a series of products ranging from pyrophosphoric acid (H 4 P 2 O 7 ) to metaphosphoric acid (H 3 PO 4 ) n [84]. XRD analysis at 180 • C, 200 Figure 13 presents the diffraction patterns of solution treated fibres at incrementally higher temperatures.…”