Colloquium
Department of Mathematics
And
Department of Physics
Michigan Technological University
Monday, July 22, 2013
at 11:00 am
Room 125 Fisher Hall
Play-doh and Packing
Elizabeth Chen
Department of Applied Mathematics
Harvard University
The Michigan Tech News story “Beyond Silicon: Transistors without Semiconductors” has been picked up and shared by several news outlets.
Minimalist model of ice microphysics in mixed-phase stratiform clouds
Fan Yang
Advisor: Raymond Shaw
Mixed-phase clouds, which can exist days even weeks, are frequently observed in the Arctic region where they play an important role in the radiation balance. Observations also show that ice particles precipitate from these clouds nearly all time. The question of whether persistent ice crystal precipitation from supercooled layer clouds can be explained by time-dependent, stochastic ice nucleation is explored using an approximate, analytical model, and a large-eddy simulation (LES) cloud model. The updraft velocity in the cloud defines an accumulation zone, where small ice particles cannot fall out until they are large enough, which will increase the residence time of ice particles in the cloud. Ice particles reach a quasi-steady state between growth by vapor deposition and fall speed at cloud base. The analytical model predicts that ice water content (wi) has a 2.5 power law relationship with ice number concentration (ni). wi and ni from a LES cloud model with stochastic ice nucleation also confirm the 2.5 power law relationship. The prefactor of the power law is proportional to the ice nucleation rate, and therefore provides a quantitative link to observations of ice microphysical properties. Figure 1 shows LES results for two ice nucleation rates: Blue points correspond to low ice nucleation rate and red points to high ice nucleation rate. It’s clearly to see that points follow the 2.5 power law as our analytical model expected. The intercept shift predicted by the minimalist model is 1.05, which is very close to the best fitted line shift in Figure 1, 5.77-4.75=1.03. This provides a compelling link between ice microphysical properties and the ice nucleation rate within the cloud, which may be used in future analysis of cloud observation.
Reference
Yang, F., M. Ovchinnikov, R.A. Shaw (2013), Minimalist model of ice microphysics in mixed-phase stratiform clouds, Geophys. Res. Lett. doi: 10.1002/grl.50700 (accepted)
Dr. Bhabana Pati visited the department on Friday, July 12, 2013. Bhabna graduated in 1997 with a Ph.D. after working with Dr. Jacek Borysow as a “laser junkie.” She developed the single mode tunable titanium sapphire laser and subsequently tunable ultraviolet laser via sum frequency generation in a non-linear crystal.
Today she is a principal scientist at Q-Peak Co. and still a “laser junkie,” trying among many other things to shoot lasers at the Moon to find out its composition via Laser Induced Breakdown Spectroscopy.
Michigan Tech has launched a new virtual tour of campus and the local area. Fisher Hall is included among the virtual walking tours. There are interactive panoramas of Fisher 135 and a First-Year Physics Lab as well.
Associate Professor Claudio Mazzoleni (Physics) and his graduate student, Swarup China, published an article in the journal Nature Communications on the structure and properties of soot produced by biomass burning.
From Tech Today.
Morphology and mixing state of individual freshly emitted wildfire carbonaceous particles
The March/April edition of the magazine Rocks & Minerals would be considerably slimmer if physics professor John Jaszczak’s contributions were extracted.
With John Rakovan (Miami University), he coordinated a series of articles on mining in the Arusha region of Tanzania. He coauthored “Miracle at Merelani,” an article on minerals found at the Karo Mine, providing electron microscope images and photos of many showy specimens from the Seaman Mineral Museum. He also edited a pictorial of Merelani, a village near the mine.
In addition, he coauthored “Fluorapatite from a Remarkable Occurrence of Graphite and Associated Minerals,” providing three photos for the article.
Lastly, Jaszczak wrote the Word to the Wise column entitled “Raman Spectroscopy in the Identification and Study of Minerals,” which introduced readers to this powerful tool for identifying and characterizing minerals.
From Tech Today.
Yoke Khin Yap (Physics) has received a $140,000 research grant for “Synthesis and Characterization of Functional Boron Nitride Nanostructures” from the National Science Foundation. It is for the first year of a three-year project totaling $420,000.
From Tech Today.
Associate Professor Will Cantrell (Physics) is quoted in an article about how to find the best professors, published on the web site OnlineSchools.org. See Online Schools.
From Tech Today.
The Faculty Factor: How to Pick the Best Professors
Learning that takes place outside of the classroom is also equally important, and frequent interaction with professors can lead to greater gains in personal development and general education knowledge, the study found. It’s all about having a professor who is accessible.
“If you can go to a professor’s office and ask him or her for help, you will be able to learn a lot more,” says Will Cantrell, an associate professor of physics at Michigan Technological University. “A lot of university-level material is difficult. You probably will get stuck on something. There’s no substitute for having someone who has already mastered the material help you get unstuck.”
When you’re looking for a new dentist or hair dresser, it’s almost a no-brainer that you get the word-of-mouth before you’re sitting in the chair and it’s too late. The same can go for professors. When shopping for classes, ask current students in your area of study for recommendations on teachers they’ve liked.
“Talk to other students. There is no substitute for this,” says Cantrell. “Ask other students what classes they liked, and more importantly, why they liked those classes and professors. Take classes from professors that helped students learn, not just the ones who were easy.”
Read more on Education Debate at Online Schools.
Claudio Mazzoleni (Physics) has received $39,937 grant from the US Department of Energy, for a three-year, $132,465 research project, ” Atmospheric Transport: Understanding Results from the DOE’s 2010 CARES and 2012 ClearfLo Campaigns.”
From Tech Today.