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Colloquia & Seminars, Fall 2016

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Thesis Defense

Characterizing Radio Continuum Sources in a Sample of Hi-GAL Massive Cores

Speaker: Mr. Jason Armstrong
Date: Friday, December 16, 2016
Time: 1pm
Room: 402 Currens Hall

Abstract: In 2012 and 2013, Olmi and collaborators conducted a survey for 6.7 GHz methanol masers with the Arecibo Telescope toward far infrared sources selected from the Hi-GAL catalog of massive cores. They reported a number of sources with weak 6.7 GHz methanol masers, possibly indicating regions in early stages of star formation. Follow-up observations were conducted with the Karl G. Jansky Very Large Array (VLA) in New Mexico to characterize the sources. This thesis presents the results of radio continuum observations of nine of the Arecibo regions. A total of 33 radio continuum sources were detected. The nature of the radio continuum sources was analyzed based on their spectral indices. Most of the sources have negative spectral indices, which is indicative of synchrotron radiation. Many of the synchrotron sources are associated with a supernova remnant in our Galaxy, while the rest are likely background radio galaxies and quasars. Evidence for thermal bremsstrahlung radiation was found toward six sources associated with the Arecibo regions, which is consistent with the interpretation of gas ionized by young high-mass stellar objects.

About the speaker:  Jason Armstrong is a physics graduate student.

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Ordering of Polyethylene Glycol (PEG) Functionalized Magnetic Iron Oxide (Fe3O4) Nanoparticles on Liquid Surfaces

Speaker: Mr. Nicholas Breslin
Date: Friday, November 11, 2016
Time: 4pm
Room: 205 Currens Hall

Abstract: Magnetic nanoparticles are of particular interest in condensed matter physics due to the nature of magnetic properties at the nanoscale that have been demonstrated to be different than in macro-scale. There has been growing motivation to create predetermined assembly of nanoparticles to fabricate two dimensional (2D) meta-materials for various applications. Prior experiments have shown the ability to create short range to long range 2D and 3D ordering using single and double stranded DNA (ssDNA/dsDNA) functionalized nanoparticles, but the logistical inability to upscale the use of DNA creates a need to explore alternative options such as polymers. Using Polyethylene Glycol (PEG) chains we can graft iron oxide (Fe3O4) nanoparticles of desired sizes. Factory manufactured oleic acid coated Fe3O4 nanoparticles are placed in toluene with Silane-PEG to achieve ligand exchange. Prior studies have shown that by introducing salts to PEG functionalized nanoparticle solutions, the nanoparticles rise to the surface forming local ordering and even crystallize at the vapor-liquid interface. Synchrotron X-ray reflectivity (XRR) and grazing incidence small angle x-ray scattering (GISAXS) conducted at the Advanced Photon Source at Argonne National Laboratory reveal that the self-assembled 2D PEG-functionalized Fe3O4-NPs only form short-range order but do not crystallize at any salt concentration. This may be due to the fact that the grafting density of the PEG on the nanoparticles is not high enough, or alternatively due to the fact that the longest Silane-PEG chains available are of 1K monomer length which could be too short to induce migration to the surface unless salt concentrations are high. It has been shown that NPs that are grafted with longer chains are more efficient for assembly and crystallization at the interface.

About the speaker:  Nicholas Breslin is a senior majoring in physics. He is the Honors College Scholar for Fall 2016. Under the Science Undergraduate Laboratory Internship (SULI) program of the US Department of Energy, he completed a summer internship at the Ames National Laboratories in Summer 2016. This internship presentation is based on the research he carried out this summer.

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Nano-Optical Phenomena of 2D Layered Materials

Speaker: Dr. Zhe Fei
Date: Friday, November 4, 2016
Time: 4pm
Room: 205 Currens Hall

Abstract: Nano-optics is a frontier of research that studies light-matter interactions in the nanometer length scale. In this talk, we present nano-optical studies of novel two-dimensional (2D) layered materials using the state-of-the-art scanning near-field optical microscopy – a unique technique allowing efficient excitation and high-resolution imaging of a variety of polaritonic modes. With this technique, we performed nano-optical imaging of plasmon polaritons in graphene, graphene layers and graphene nanostructures, phonon polaritons in hexagonal boron nitride, as well as exciton polaritons in transition-metal dichalcogenides. Novel physics and applications associated with these polaritons will be discussed.

About the speaker: Dr. Zhe Fei is an Assistant Professor at the Department of Physics & Astronomy, Iowa State University. His research interests include exploration of nanoscale light-matter interactions in a variety of novel materials including graphene, two-dimensional layered materials beyond graphene, and other complex materials.

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Engineering and Leadership at John Deere

Speaker: Cory Randolph
Production Supervisor at John Deere Harvester Works
Date: Friday, September 30, 2016
Time: 4pm
Room: 205 Currens Hall

Abstract: This presentation will cover my work experience at John Deere. It will start with covering my engineering internships and some of the projects I was given as a summer intern. After going over my engineering internships, I will then speak to my full time experiences right out of college as the Lead Manufacturing Engineer for the Articulating Dump Truck product line and some of the projects I was given. Finally, I will discuss how the manufacturing experience I gained helped me to become a production supervisor at Harvester Works.

About the speaker: Mr. Cory Randolph is an Engineering Physics graduate of WIU. Currently, he works as a Production Supervisor at John Deere Harvester Works. His daily responsibilities include managing 40 operators in two different departments to help achieve daily production goals. This will often include working with Engineering, Quality, and Supply Management to overcome manufacturing issues that can hinder the manufacturing process.

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Special Mathematica Workshop

Speaker: Mrs. Natalia Andreev
Department of Physics, WIU
Date: Friday, September 16, 2016
Time: 3pm
Room: 205 Currens Hall

Abstract: This is a special introductory training session on Mathematica. We will start with basic aspects of using Mathematica. The training session will last for approximately 2 hrs. All students are invited to come and learn to use Mathematica. Those who are already familiar with the program can also attend and gain more practice.