Depending
on the location, time of year, and time of day, any or all of the following
differences between cities and their surroundings) can be important: albedo (reflectivity
of the surface), surface roughness, emissions of heat, emissions of moisture,
and emissions of particles (that affect net radiation)and the growth of cloud
droplets.
It is not
surprising, therefore, that the highest ratio of oil and gas pools to volume of
sediment is found in rock no older than 2.5 million years—young enough so that
little of the petroleum has leaked away—and that nearly 60 percent of all oil
and gas discovered so far has been found in strata that formed in the last 65
million years.
In order for the
structure to achieve the size and strength necessary to meet its purpose,
architecture employs methods of support that, because they are based on
physical laws, have changed little since people first discovered them——even while
building materials have changed dramatically.(44)
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