Cooperative Institute for Research in Environmental Sciences

All day
 
 
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Atmospheric Chemistry Program Seminar

Atmospheric Chemistry Program Seminar

Chemistry of peroxy radicals and soot formation at combustion conditions by Prof Sandeep Sharma, CU Boulder, PChem

Abstract:
"In this presentation, I will focus on the chemistry of peroxy radicals and soot formation at combustion conditions. Both these topics are of immense technological importance and will also allow me to present the latest theoretical techniques used to study them. These include the use of automated mechanism generators to build complex reaction mechanisms, the use of transition state theory to calculate rates of elementary reactions, and the use of the semiclassical method for calculating the partition function of anharmonic vibrational modes. The aim is to physically motivate these techniques and highlight the conditions under which we expect them to be predictive and also discuss their shortcomings. I will end the presentation with a short review of the latest work from my group that aims to address some of the shortcomings."
 

date

Monday, October 30, 2017
12:00pm to 1:00pm

location

Ekeley S274

contact

Anne.Handschy@Colorado.EDU
2017-10-30
 
INSTAAR Noon Seminar

INSTAAR Noon Seminar

Laurentide ice sheets, the Isthmus of Panamá, & the Great American Biotic Interchange: A tectonic red herring inserted between climatic cause and biological consequence by Dr. Peter Molnar
Geological Sciences & CIRES, University of Colorado Boulder


Two events occurred virtually simultaneously at ~2.5 Ma: the first big ice sheet of Northern Hemisphere Ice Ages reached as far south as St. Louis, and largely large mammals crossed through the Isthmus of Panamá from North to South America and vice versa in the Great American Biotic Interchange.  An emergent isthmus is necessary for such animals to change hemispheres.  In a popular myth, recited by textbooks, the isthmus emerged near ~2.5 Ma or perhaps slightly earlier, and by doing so, it altered Atlantic Circulation sufficiently to enable ice sheets grow on Canada.  I contend that such logic is inverted. Large Laurentide ice sheets pushed the intertropical convergence zone (ITCZ) southward so as to cool and aridify eastern Panamá, and create a savannah-like environment.  Most of the animals involved in the Great American Biotic Interchange seem to have been savannah-dwellers, and I presume that they would have avoided the swamps, jungles, snakes, crocodiles, mosquitoes, and other nasty predators in eastern Panamá before savannah-like environments drew them in and facilitated safe passage.  So, the Great American Biotic Interchange is not a symptom of a tectonic change that enabled Ice Ages, but instead a consequence of those Ice Ages.

 

Coffee and social hour @ 11:45 am. 

date

Monday, October 30, 2017
12:15pm

location

SEEC room S228 (Sievers Conference Room)
2017-10-30