PEGASUS Seminar Series: Structure and dynamics of materials under pressure (Xue Yong)

Please join us this Tuesday, August 16 in Physics 175 for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Xue Yong, who studies the effects of pressure and temperature on materials.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar.
Title: Structure and dynamics of materials under pressure
Abstract: The response of a material to increasing pressure and temperature is an interesting and practical research that attracts many investigator in geophysics and geochemistry, as well as in material science. High pressure and temperature provide large compression energy (PV) and thermal (TS) energies, which are able to break intermolecular or intra-molecular interactions in most stable materials. Therefore, at extreme conditions, most ambient-pressure liquid and solid materials become unstable and transform into new phases with higher densities. In this talk I am going to present some interesting results bout the response of materials to high pressure by computer simulation. Three examples will be presented. First is the using of high pressure technique to synthesis high energetic materials based extended CO2. Second is the novel interactions of silicate with small molecular gas at high pressure and temperature. Third is the a new sheared – ice-Ih under moderate pressure

PEGASUS Seminar Series: Investigation of Solar Influence on Thermospheric Density Variation (Clifford Ridley)

Please join us this Tuesday, August 2nd in Physics 175 for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Clifford Ridley from ISAS, who investigates the effects of the interaction of the Sun’s magnetic field with the earth on particles in the thermosphere.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar.

Title: Investigation of Solar Influence on Thermospheric Density Variation

Abstract: Due to undulations in the heliospheric current sheet, the Earth’s orbit is divided into sectors where the sun’s interplanetary magnetic field (IMF) at the Earth is primarily directed towards or away from the sun. During the year 2003, the IMF direction at the Earth changes with a nearly consistent periodicity of 12-15 days, leading to well defined IMF sectors. During this same period, thermospheric neutral particle densities and electron content are higher during times when the IMF is directed towards the sun, and lower when the IMF is directed away from the sun. Possible links between the IMF polarity and thermospheric densities were investigated, with a focus on the spatial distribution of thermospheric density variations between IMF sectors, as well as the temporal changes of solar wind and IMF parameters and geomagnetic activity indices during the Earth’s transition between IMF sectors.