The Medieval Global Temperature Optimum, sometimes referred
to as the Medieval Warm Period, took place between 950 AD and 1250 AD. During
this time, an unusual climate lasted in the North Atlantic region that may have
been related to other climate events during the time. While the period saw
unusually warm temperatures in some regions, globally the climate was cooler. Evidence
suggests that even in the Northern Hemisphere where the climate was most
visible, temperatures are now beyond those experienced during medieval times. The
known causes of this time period were higher than average solar radiation and
less volcanic activity. Evidence also suggests that changes in ocean
circulation patterns played a role in bringing warmer seawater into the North
Atlantic. After the Medieval Warm Period, the Little Ice Age was a period of
cooling that occurred between 1300 AD and 1870 AD. This period is linked
directly to advances in technology harnessing more natural power and
fossil-fueled power near the end of the period. It also created specialized areas
of agricultural regions, and aided in the expansion of maritime Europe. Due to
technological advances and agricultural revolutions brought on by this climate
change, populations flourished. This is evidenced by the art and architecture
from the time period, expressing ice-skaters and enjoyable winters, indicating
people were more able to withstand these climate shifts.
Saturday, October 25, 2014
Air Pollution in London
Air pollution, the presence or introduction into the air of
a substance which has harmful or poisonous effects, has a moderate effect on
the city of London, England. According to the Real Time Air Quality Index, London
generally emits air ratings of “good” or “moderate”. A good rating indicates
that air quality is considered satisfactory and that the pollution poses little
health risks. A moderate rating indicates that air quality is acceptable, but
that some pollutants can cause a moderate health risk for a small amount of
people who are unusually sensitive to air pollution. Most pollution in London
is caused by road transport and domestic and commercial heating systems. The
two pollutants of most concern are microscopic airborne particles, known as
PM10, and nitrogen dioxide (NO2) - a toxic gas. There is also evidence that
much of the pollution in the southern UK comes from winds bringing up pollution
from the continent of Europe. In order to reduce the amount of air pollution,
the city has put in new regulations. To reduce emissions from transport, the
city is cleaning the bus fleet, capping the age of their taxi’s, setting new
and tighter standards for the London Low Emission Zone, encouraging electric
and low emission vehicles, and investing in cycling. In general, the city is
also improving energy efficiency in homes and embedding air quality within the
planning system.
To view the real time updates from the Air Quality Index, visit the London site here
Friday, October 3, 2014
Titanium
Titanium, Ti, is a transition metal with a silver color and
atomic number of 22. It was discovered in Cornwall, Great Britain, by William
Gregor in 1791. The metal has low density, but high strength and is highly
resistant to corrosion in sea water and chlorine. It is also paramagnetic and
has low electrical and thermal conductivity. It is widely distributed in the
Earth’s crust and is found in most living things such as rocks, water, and
soil. The most common compound is titanium dioxide, which is used in the
manufacturing of white pigments. Other notable compounds include titanium
tetrachloride, which is a component of smoke screens and catalysts, and
titanium trichloride, which is used as a catalyst in the production of
polypropylene. It can also be alloyed with iron, aluminum, vanadium, and
molybdenum, and various other elements to produce strong, lightweight alloys
for jet engines, missiles, spacecraft, military, medical prostheses, orthopedic
implants, dental instruments, sporting goods, jewelry, and many other products.
Since it is non-toxic even in large doses, titanium can be used without too
much threat. However, as a powder or in the form of metal shavings, it can be a
significant fire hazard and when heated, an explosion hazard.
Below is a map of titanium production worldwide
Subscribe to:
Posts (Atom)