Physics Newsblog

New Funding for Pandey and Nemiroff

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Ravi Pandey (Phys) has received $75,000 (with a potential award total of $726,291) from the US Department of Defense-Army Research Laboratory for the first year of a potential three-year research and development project titled “First Principles Studies of Structure-Property Relationships in Two-dimensional Nanomaterials Beyond Graphene for Defense Applications.”

Robert Nemiroff (Phys) has received $30,000 of $238,362 from the National Aeronautics and Space Administration for the first year of a three-year project titled “Supporting Astronomy Picture of the Day.”

Read more at Tech Today.

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Thresholdless nanoscale lasers and the promises of metallic nano-cavities

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Mercedeh Khajavikhan
Mercedeh Khajavikhan

Physics Colloquium
Michigan Technological University
Thursday September 25, 2014
4:00 pm 139 Fisher Hall

Thresholdless nanoscale lasers and the promises of metallic nano-cavities

Mercedeh Khajavikhan
Assistant Professor, College of Optics and Photonics (CREOL), University of Central Florida

Partially sponsored/funded/by the Visiting Women & Minority Lecturer/Scholar Series

View the Abstract

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Jaszczak Publishes on Spectacular Sulfides

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The Mineralogical Record
The Mineralogical Record

Professor John Jaszczak (Physics), adjunct curator at the A. E. Seaman Mineral Museum, published a paper in the September/October issue of The Mineralogical Record, “Spectacular Sulfides from the Merelani Tanzanite Deposit, Manyara Region, Tanzania.” The paper’s coauthors are Simon Harrison, Mike Keim, Mike Rumsey (Natural History Museum, London) and Michael Wise (Smithsonian Institution).

Vol. 45, No. 5 September – October 2014

From Tech Today.

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Super-Terminal Raindrops Verified

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Warp-Speed Raindrops

It’s a rain race out there. In the meteorological equivalent of breaking the light-speed barrier, new research shows that the smaller droplets in a rainstorm often surpass what appears to be the speed limit for rain.

“What surprised us was not so much seeing the superterminal drops,” says physicist and co-author Raymond Shaw of MTU, “but seeing the deeper, compelling patterns.” He explains that as rain falls harder, the fraction of superterminal, or speeding, small drops increases.

Read more at Science Magazine, by Phil Berardelli. This article was posted on June 12, 2009.

Geophysical Research Letters 2014
Geophysical Research Letters 2014

Further evidence for super-terminal raindrops
M. L. Larsen1, A. B. Kostinski and A.R. Jameson
DOI: 10.1002/2014GL061397

A network of optical disdrometers (including laser precipitation monitors and a 2-dimensional video disdrometer) was utilized to determine whether the recent reports of “super-terminal” raindrops were spurious results of drop breakup occurring on instrumentation. Results unequivocally show that super-terminal raindrops at small (less than 1 mm) sizes are ubiquitous, are measurable over an extended area, and appear in every rain event investigated.

Read more at Geophysical Research Letters, published by Wiley Online Library in 2014.

Confirmed: Some raindrops fall faster than they should

Five years ago, scientists reported that raindrops, especially small ones, often fall through the air much faster than they should. Some researchers have suggested that these “super-terminal” raindrops (ones traveling more than 30% faster than their terminal velocity, at which air resistance prevents further acceleration due to gravity) were fragments of larger drops that had splattered off the team’s instruments, with the smaller bits retaining the speed the larger drop had before it struck the instrument. But new research hints that the speedier-than-expected drops are the result of natural processes—and that, moreover, they make up a substantial fraction of rainfall.

Read more at Science Magazine, by Sid Perkins. This article was posted on August 26, 2014.

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Kamal Dhungana Research

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Kamal Dhungana Research
Schematic diagram of a fluorinated boron nitride nanotube based spin filter device.

Fluorinated boron nitride nanotube as an ideal spin filter

Advisor: Dr. Ranjit Pati

Understanding the electronic structure and the transport property of nano scale materials is of fundamental importance, since these materials are the ultimate candidates for the future of nano technology. Several nano materials, such as quantum dots, semiconducting nano-wires, and organic molecules, have been explored both theoretically and experimentally as the components of electronic circuitry over the last two decades. Among several interesting nano materials, metal free magnetic nano materials are found to be very enticing due to the presence of magnetism in the absence of magnetic ions. Traditionally, the magnetism comes from partially occupied d and f states in the materials; however, this understanding is not always true since s and p states are found to contribute to the magnetism in the metal free magnetic materials. The main advantage of these materials is their high Curie temperature; as a result, they can be utilized in room temperature spin-electronics (spintronics). Recently, using a first-principles approach, we have demonstrated that the fluorinated boron nitride nanotube (BNNT), which is a metal-free magnetic entity, can be used as an excellent spin filter. All majority spin carriers are almost completely blocked while passing through the fluorinated BNNT channel, allowing only the minority spin carriers to pass. We have shown that the long range ferromagnetic spin ordering in fluorinated BNNTs occurs at a temperature much above room temperature.

For more information, please visit my webpage: http://www.phy.mtu.edu/~kbdhunga

By Kamal B. Dhungana

Reference:

Kamal B. Dhungana, Ranjit Pati, Fluorinated Boron Nitride Nanotube Quantum Dots: A Spin Filter. J. Am. Chem. Soc., 2014, 136, 11494–11498. 

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