Mozharivskyj's research looks at the factors that control the structure and magnetic properties of Gd5Si2Ge2 and related phases. He has shown that tuning both the structural and magnetic behavior of these materials can be achieved. He can't yet prepare a material whose properties exceed those of Gd5Si2Ge2; he has, however, developed an effective chemical toolbox for optimizing magnetocaloric properties. Paper SP.01. Lab website at: http://www.chemistry.mcmaster.ca/mozhar/MCE%20project.htm
SULFUR IN HARSH PLACES NEW MINERAL DISCOVERED
Ronald Peterson of Queen's University in Kingston, Ontario, will report the discovery of a new mineral, meridianiite (MgSO4-11H2O). Sulfate minerals occur in a wide variety of natural environments where they often precipitate from aqueous solution. Sulfate minerals also occur in mine waste through the interaction of water, oxygen, and sulphide minerals, such as the pyrite in the fine-grained waste rock discarded to the surface environment. These sulfate minerals are able to form in a wide range of temperature, relative humidity, and pH and often their crystal structures control the means by which metals and semi-metals are sequestered and then released from mine waste over time. Once crystallized, these minerals often continue to react in nature as environmental conditions change. These materials can react very quickly when removed from the conditions under which they are stable. The samples must be stabilized for transport or studied in place in the field.
The TERRA portable X-ray diffractometer allows the identification of these reactive materials as they are sampled. The new mineral meridianiite was found in sub-zero temperature fieldwork. The TERRA instrument is a commercial version of the X-r
|Contact: Phillip Schewe|
American Institute of Physics