Year: 2015

Our outstanding students are winning honors and awards again. Emily Thompson (Junior) is a winner of the Barry M. Goldwater Scholarship and the Outstanding Junior in Science in the College of Engineering and Science. Marharyta (Margo) Petukh is the Outstanding Graduate Researcher in the College of Engineering and Science.

Biophysics student Marharyta (Margo) Petukh has been named Clemson University’s Outstanding Graduate Researcher for 2015.

The Spring 2013 issue of Schrödinger’s Tiger described the Department’s participation in the newly awarded NASA sounding rocket experiment “MTeX,” led by the University of Alaska to study turbulence in the mesosphere-lower thermosphere region. During the holiday break of 2014/2015 I was fortunate enough to travel with Clemson coinvestigator Dr. Gerald Lehmacher to Fairbanks for a one-week period to see firsthand the preparation for the launch of two sounding rockets with MTeX science payloads at the Poker Flat Research Range. With the launch window opening a week after our visit, we mainly oversaw the assembly of the payloads and prepared the CONE ionization gauge before it became inaccessible under the nosecone. The MTeX mission aimed to explore ways in which meteorological conditions can influence the impact of solar radiation received by the atmosphere.

With neutral density as a tracer, turbulence measurements during specific atmospheric conditions of a mesospheric inversion layer allow us to identify a representative distribution of turbulence activity and, thus, better characterize turbulent transport in the upper atmosphere between 60 and 120 km. Two rockets were launched on January 26, 2015 at 00:13 and 00:46 a.m. in order to obtain in situ measurements of turbulence, density and temperature. With the CONE ionization gauge, turbulence is identifiable as small oscillations of 0.1 to 1% in the observed ion current, which is proportional to density. The remaining instruments in the science package (positioned on the four deployable booms) measured aspects of atmospheric plasma using different forms of Langmuir probes, as well as an impedance probe. As a significantly cheaper and as yet unproven method of measuring turbulence and density variations, a three-axis MEMS accelerometer was included in the payload, the subject of my research for the past few semesters. The plasma and accelerometer experiments were built by Embry-Riddle Aeronautical University. Working with Dr. Lehmacher, the Sounding Rocket Instrumentation Creative Inquiry section has explored how we might be able to use the output of the sensitive accelerometer to provide a further means of measuring the atmospheric drag and density. With micro-g resolution and 5 kHz sampling rate, I have previously characterized the amount of noise present in the signal by spectral analysis on data from drop tests performed from the breezeway, as well as at rest in the lab. With the rockets having recently flown we now have flight data and will use it to potentially verify some structures seen by CONE and later calculate drag coefficients of the rocket in flight. The observed accelerometer shows 35 seconds of in-flight measurements. During this period of time, the rocket is being configured for the upward leg science window of the flight. We first see a period of intense modulation from the rocket engine which tapers off as the second stage motor burns out. Then spin effects and precession of the rocket’s velocity vector are visible from 40 seconds to 50 seconds. At this point the nosecone is ejected from the payload. When the nosecone and its shroud clear all the instruments, it is pushed out of the same trajectory as the payload by ejecting a slug radially at high velocity. The despin stage then brings down the rotation rate to 2 Hz followed by booms deploying and payload separation in rapid succession. As final preparation for measurement, attitude control systems further adjust the spin rate and orientation.

Another part of my experience was the lidar which was also at Poker Flat. This technology was used to measure the telltale temperature structure indicative of a mesospheric inversion layer needed for launch. Using powerful pulsed solid-state and dye lasers, certain atmospheric constituents left from meteorite trails are excited and the resulting photons are collected or, (in case of a Rayleigh lidar), backscatter from nitrogen and oxygen is observed to determine counts and doppler shifts at heights from 40 km to over 100 km. With the Rayleigh lidar, a brilliant green beam was visible shooting into the atmosphere that was truly an amazing sight. The facility also operates an iron lidar, which requires an ultraviolet laser and is, thus, invisible to the human eye. We stayed into the night to watch as a team of graduate students and Dr. Richard Collins, who is also the principal investigator of MTeX, calibrated and operated the system and obtained a temperature profile in preparation for the launch window.

Lastly we did indulge in a bit of tourist allure on our expedition to the final frontier. Heavily layered and armed with a rudimentary knowledge of photography, we stayed late into the night atop Ester Dome to watch the aurora. The hours of 10 p.m. to 2 a.m. were filled with spurts of activity in green from atomic oxygen, as well as periods of nothing more than a dull glow. After tweaking a few camera settings, we obtained some reasonably picturesque scenes of green ribbons decorating the sky. Then as we gave up for the night already quite content with the show, we were blown away by striking white and pink streaks which writhed and darted about at a rapid pace. These colors only show up as a combination of the same green and a red also produced by atomic oxygen at higher altitudes only visible during periods of high solar fluxes.

– Brandon Burkholder, Graduating Senior 2015

Introductory Physics and Astronomy courses are available online this summer. See what is offered and how to take them.

It is said that the excitement of learning separates youth from old age, and that we stay young as long as we are learning. A true testament to this statement was the recent “Nanotechnology Day,” cohosted by the Clemson Nanomaterials Center (CNC) and the Roper Mountain Science Center (RMSC) in Greenville, South Carolina. On March 14, 2015, “Pi Day,” as it is called (for its similarity to the ubiquitous irrational number π), attracted about 800 visitors aged 7 to 70 years, who attended the Nanotechnology Day event despite the pouring rain. While it was raining outside, it was enthusiasm and curiosity that was pouring inside the RMSC. The enthusiasm of kids and senior citizens alike reaffirmed the fact that no matter Clemson Nanomaterials Center Faculty and Research Group how old you are, learning about about things at the nanoscale is definitely fun.

To captivate the enthusiasm and unleash the imagination of its young visitors, CNC brought its nanolab to the doorstep and illustrated intriguing physics phenomena through simple experiments. Some such activities included: the art of levitation, which demonstrated a floating piece of graphene on magnets, (much like the magic carpet of the Arabian nights); the extraction of graphene from graphite in pencil that won the Nobel prize (pencil to Nobel); and, the magic of ferro fluids, the power of nano-sponges, the nano -movers and shakers (nano diving-board like cantilevers), just to name a few. Other nano activities using the RMSC’s Network Nano Days Physical Kit from the Nanoscale Informal Science Education (NISE) grant were also included. The audience was awed by the possibility of delivering nanomedicine and storing energy using nanomaterials. Indeed, many of them truly learned, despite its size, that nanotechnology is no small thing. “It was a really fun and exciting experience to teach kids about nanoscience,” remarked Dr. Sriparna Bhattacharya, Research Assistant Professor at CNC, “I believe learning went both ways. We learned as much as they did.”

Anthony Childress, a Physics and Astronomy graduate student, and a member of CNC, presented “The Magic of Nanomaterials,” a thirty-minute talk where he introduced the interesting physical phenomena at the nano-level. The audience, which included both kids and seniors, was thrilled and asked him many interesting questions. He concluded his talk with a live demonstration of making nanosweets (nanocarbons from sugar and drain cleaner) that undoubtedly piqued the interest of everyone. “Clemson is being recognized as an international center of excellence for nanomanufacturing,” said Dr. Apparao M. Rao, Director of CNC, “One of our goals is to convey the excitement of cutting-edge research developed at CNC to K-12 and undergraduate students through programs such as the Nanotechnology Day.”

“We intend to develop a larger workforce in South Carolina and the nation,” explained Dr. Ramakrishna Podila, Assistant Professor of Physics at Clemson. “We want to train the next generation scientist to solve future challenges in the fields of energy and biomedicine through innovations in nanoscience.”