Never complain about what God did not give… be happy with
what you have ~ there are so many hindrances that you do not come your way !
In Chennai, it is winter ~ can hear that it is
cool in the morning and that one perhaps needs to cover the ears – lest one
catches cold… Chennai is hot for most part of the year ~ if you do not know
much about Chennai – it is 29°C and the
low can be around 19°C; away in London it is 1°C and there are Antarctica, Alaska, Siberia and
more…. There is no debating that the highland
interior of Antarctica is the coldest region
on earth. Only a handful of research stations exist in this hostile environment
and the Russian station at Vostok is the coldest of all. It is reported that there are more than a
score of researchers during summer and around a dozen in winter. The world’s lowest observed surface air
temperature was recorded on July 21, 1983 when a reading of -128.6°F (-89.2°C)
was made. There are bone chilling
places and what we perceive at Chennai as cold is no mosquito-bite even.
When it rains [very few spells at Chennai even during
monsoons], it damages the roads and it becomes a nightmare to drive on pot-hole
filled roads after rains. Elsewhere there are problems of different kind ~ in
sub-zero temperatures at places, water freezes……… and when thawing occurs,
there would be floods.
In countries affected by winter, roads would turn to ice
and vehicles cannot move on. The only safe way to treat icy surfaces is to
clear excess snow with a snow shovel or stiff broom, and sprinkle sharp sand
which provides a degree of traction to prevent slipping. Like what is being
experienced in London now, US has had
some nasty winters lately — from the "Snowmageddon" of early 2010 to
more recent blizzards that crippled New York City and even theDeep South - there roads are de-iced to enable vehicular
movements. Salt is a good de-icer
because it lowers the freezing point of water, letting it remain a liquid at
colder temperatures. Highway agencies across the U.S. dump roughly 15 million
tons of road salt every winter, capitalizing not only on its antifreeze
abilities, but also its large granules, which can provide traction for
vehicles' tires against existing ice (often with the help of sand). The state
uses a salt and dirt mix to clear snow and ice off the roads.
Winter
in Manchester Airport
Sure have studied of - MgCl2 - Magnesium
chloride, is the name for the chemical
compounds of salts. These salts are typical ionic halides, being
highly soluble in water. The hydrated magnesium chloride can be extracted from
brine or sea water.
In countries where the winter is extreme, there is
‘de-icing’ i.e., the removal of snow, ice or frost from a surface. Anti-icing
is understood to be the application of chemicals that not only de-ice, but also
remain on a surface and continue to delay the reformation of ice for a certain
period of time, or prevent adhesion of ice to make mechanical removal
easier. De-icing is accomplished by
mechanical methods (scraping, pushing); through the application of heat; by use
of dry or liquid chemicals designed to lower the freezing point of water (various salts or brines, alcohols, glycols);
or by a combination of these different techniques.
Road being
de-iced
Understand that de-icing of roads traditionally is done with salt, spread by
snowplows or dump trucks designed to spread it, often mixed with sand and
gravel, on slick roads. Sodium chloride (rock salt) is normally used, as it is
inexpensive and readily available in large quantities. Even this could be affected as salt water
still freezes at −18 °C (−0 °F). The
disadvantage is that salt has a strong tendency to cause corrosion, rusting the
steel used in most vehicles and the rebar in concrete bridges.
Some see more dangers out of road salt as they link it to
diverse array of environmental ills, from aquatic "dead zones" and
salt-damaged plants to poisoned amphibians, wounded pets and possibly even
increased cancer risk in humans. Also
read that a group of trucking companies is asking Connecticut lawmakers to ban
an ice-melting chemical the state uses on its roads, saying it’s too
corrosive. The association wants
de-icers like magnesium chloride to be declared illegal as they claim that the chemical is corroding trucks at an
unprecedented rate and officials should be worried about it affecting bridge
metal.
In Western countries, there are concrete roads…. Concrete,
when setting from a plastic to hardened condition, goes through a number of
chemical reactions. It is stated that Magnesium
chloride for deicing is effective in reducing the temperature at which water
freezes. The problem begins as the magnesium chloride comes into contact with
the now deiced concrete surface and remains contained in the melt water, and
permeates into the concrete, damaging it and making financial impact more felt
when it comes to relaying.
Different places, different atmosphere, and
different problems… far more than what we can think of….
With regards – S. Sampathkumar
24th Jan 2013.
Photo courtesy : www.dailymail.co.uk
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