Saturday, 4 August 2012

How does ballast-less track provide safe travel?

Ballast is a prime component of the track that acts as a vibrant medium to transmit from the rail surface the weight of the train down to the formation, the wells set on prepared terrain. It ensures a cushioned and smooth run for the train and precludes the longitudinal displacement of the rail called creep. In ballast-less track, as the name suggests the ballast is replaced by a bed of concrete.
          The rails rest on rubber pads placed over concrete sleepers, which are fixed on the concrete bed. The ballast-less track helps to eliminate the evils of dust and noise pollution and proves suitable for underground railway also. So it is also safe for travel.

Like ordinary paints do metallic paints also fade?

Metallic paints do fade. It depends on the quality and the type of the aluminium paste used. Usually in most of the metallic paints, the commonly used pigment is aluminium pigment in the form of paste. Two types of aluminium pigments are available in the market. One is leafing, and the other is the non-leafing aluminium pigment will not get dispersed (or dispersed partially) with the resin while mixing, whereas the non-leafing will get completely dispersed with the resin during mixing.
            So, if the metallic paint contains the leafing aluminium pigment it will get faded over a period of time, whereas if it contains a non-leafing aluminium pigment it will not fade for a longer period.Example: The street lampposts on the roads and highways which are coated with metallic paints appear dull after a short period of coating, whereas cars coated with metallic paints shine even after a long time.

Why do runners run in anti-clockwise direction?

As the heart is on the left side, for humans and animals, running anticlockwise makes the centrifugal force of the body to act from left to right.Whereas it is from right to left for clockwise running.
        Superior venacava (the principal vein carrying blood to the heart) takes blood to the heart aided by heart suction.This vein carries blood from left to right.
        Centrifugal force due to anticlockwise running helps this suction.If we run clockwise, the centrifugal force impedes suction. That is why, in olden days, health officers ensured that all carnival merri-go-rounds were run only in the anticlockwise direction.
        Racing tracks, animal shows in circuses, bullock-drawn pelton wheels, all mostly have only left turns. Stairways in temple towers have only left turns for going up. Clockwise running tires people, especially, children, easily.