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Thursday, January 24, 2013

Feeling the winter in Chennai ~ thank God you are in Chennai

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.
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