what is metamorphic rock

Metamorphic rocks are formed by the recrystallisation of older rocks, when subjected to intense heat or pressure or both, within the earth’s crust. Clay is metamorphosed to slate, limestone to marble and sandstone to quartzite Slate Slate is derived from fine-grained sand-free clay sediments. The characteristic cleavage planes of slate were produced when the clay …

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soda lime silica glass

Modern glass is manufactured from sand (silica), soda ash (sodium carbonate) and limestone (calcium carbonate), with small additions of salt-cake (calcium sulphate) and dolomite (magnesian limestone). This gives a final composition of typically 70–74% silica, 12–16% sodium oxide, 5–12% calcium oxide, 2–5% magnesium oxide with small quantities of aluminium,iron and potassium oxides. The addition of …

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green wall detail

Green walls (living walls) are constructed with the appropriate growing medium contained in matting or blocks fixed directly to the building façade. Provision for watering and maintenance is necessary and the whole system requires refurbishment at regular intervals. Green walls derived from climbing plants supported on stainless steel rods, ropes and mesh are more easily …

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runway aiming point

Aiming points are placed on runways of at least 4000 ft in length to provide enhanced visual guidance for landing aircraft. Aiming point markings consist of two bold stripes, 150 ft long, 30 ft wide, spaced 72 ft apart symmetrically about the runway centerline, and beginning 1020 ft from the threshold.