Within the overall transport process, attenuation processes may cause movement of the
chemical to differ from that of the bulk flowing groundwater, for example dispersion, sorption
and chemical or biological degradation of the chemical. Such attenuation processes
potentially act to mitigate the impact of chemicals and are a function of both the specific
chemical and geologic domain. Indeed, attenuation may vary significantly between individual
chemicals and within different geological settings.
The International Year of Planet Earth (IYPE) was established as a means of raising
worldwide public and political awareness of the vast, though frequently under-used,
potential the Earth Sciences possess for improving the quality of life of the peoples
of the world and safeguarding Earth’s rich and diverse environments.
The International Year project was jointly initiated in 2000 by the International
Union of Geological Sciences (IUGS) and the Earth Science Division of the United
Nations Educational, Scientiﬁc and Cultural Organisation (UNESCO).
Humankind’s fascination with Mars predates
recorded history. The bright planet with the reddish tint
is unique among the other celestial objects. Tycho
Brahe’s observations of its unpredictable motion were
deciphered by Johannes Kepler in the early 17th century
as he developed his laws of planetary motion.
Galileo trained his telescope on Mars and saw it as a
disk in 1610. Later in the 1600s, Christiaan Huygens
and Gian Cassini drew the first maps of the Martian
This report is a product of the Committee on USGS Water Resources
Research, which provides consensus advice to the Water Resources Division
(WRD) of the U.S. Geological Survey (USGS) on scientific, research, and
programmatic issues. The committee is one of the groups that works under the
auspices of the Water Science and Technology Board (WSTB) of the National
Research Council. The committee considers a variety of topics that are
important scientifically and programmatically to the USGS and the nation and
issues reports when appropriate....
Applications of mechanical engineering are found in the records of many ancient and medieval societies throughout the globe. In ancient Greece, the works of Archimedes (287 BC–212 BC) deeply influenced mechanics in the Western tradition and Heron of Alexandria (c. 10–70 AD) created the first steam engine. In China, Zhang Heng (78–139 AD) improved a water clock and invented a seismometer, and Ma Jun (200–265 AD) invented a chariot with differential gears.