Linear System of Equations

Let us look at some examples of linear systems: Suppose a, b ∈ Consider the system ax = b. If a 6= 0 then the system has a unique solution If a = 0 and: a) b 6= 0 then the system has no solution. b) b = 0 then the system has infinite number… Continue reading Linear System of Equations


How To Reach To The Equilibrium Relative Humidity

How equilibrium relative humidity (ERH) works is obvious in one way but quit stable when trying to apply the concepts to real life situation. To begin with, you will have to imagine invisible water molecules moving around in the air. The important fact: Most materials absorb water to a greater or lesser extent The next… Continue reading How To Reach To The Equilibrium Relative Humidity


Amazon is warning customers and refunding unreliable eclipse glasses sold on its site — Quartz

We’re nine days from the first total solar eclipse to be seen in America in nearly a century, and eclipse-watchers are frantically organizing travel and equipment to ensure a good view, including protective glasses. But some people who purchased those glasses on Amazon received warnings today from the retailer not to use them. Amazon’s email… via… Continue reading Amazon is warning customers and refunding unreliable eclipse glasses sold on its site — Quartz


Vertical cities: farewell horizontal?

I love this urban style, it is perfect

Paul Dobraszczyk

Robin Hood’s Bay, North Yorkshire

Recently, whilst holidaying on the northeast coast of England, I became fascinated by the vertical quality of the built environment there. In the Yorkshire coastal settlements of Staithes, Runswick Bay, Whitby and Robin Hood’s Bay, many of the houses are constructed on steep-sided land fronting natural bays or man-made harbours. Built mainly from the 16th century onwards, these villages and towns presented a remarkably dense built environment, presumably to take full advantage of what nature had provided – to cash in on the lucrative coming together of sea and land, whether through fishing in the case of Staithes and Whitby or smuggling at Robin Hood’s Bay.


Whitby harbour

The density of these settlements – their small houses all connected by extremely narrow cobbled paths and steep steps – and their fascinating vertical topography reminded me of the favelas of Rio-de-Janeiro and other informal housing…

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America’s Plastic Legacy

important post


I type this on a plastic keyboard, my lunch leftovers stored in a plastic container, as my infant daughter sleeps nearby next to her plastic pacifier in a rocking sleeper made of plastic. Plastics are one of humanity’s most wide-reaching, versatile and practical inventions, an influential creation arguably on par with the smelting of metal, but these unnatural materials have levied high ecological costs. Plastic bits pollute the world’s oceans, beaches, and rivers. Plastics’ parent chemicals move through the food chain, from plankton to people, into our cells.

Is there a patch of planet earth untouched by plastics? At Aeon, Rebecca Altman visits New Jersey’s old Union Carbide plant, where her father used to work, and where modern petrochemical plastic was first manufactured. Through this father-daughter tour, she assess the worldwide legacy of petrochemistry, its origins, etymology and toxic ubiquity, and her dad talks about what he saw…

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