The University of Mississippi
Department of Physics and Astronomy

Seminars/Colloquia, Fall 2017

Unless noted otherwise, Tuesday Colloquia are at 4:00 PM
with refreshments served 15 minutes before each colloquium.

Scheduling for additional seminars will vary.

Date/Place Speaker Title (and link to abstract)
Tue, Aug 10
Lewis 101
John Clem
Department of Physics and Astronomy
University of Delaware
NASA Balloon Programs AESOP-lite and ANITA
(PDF)
Tue, Aug 22
Lewis 101
Department Faculty
Department of Physics and Astronomy
University of Mississippi
Introduction to Department Research, followed by Ice Cream Social.(PDF)
Tue, Aug 29
Lewis 101
Mike Reep and Scott Watkins
Department of Physics and Astronomy
University of Mississippi
Machine Shop Physics
Tue, Sep 5
Lewis 101
Vahid Naderyan
Department of Physics and Astronomy
University of Mississippi
MEMS Microphones
Tue, Sep 12
Lewis 101
No Colloquium
 
 
(Graduate Student Comprehensive Examinations)
Tue, Sep 19
Lewis 101
Ron Miles
Department of Mechanical Engineering
State University New York — Binghamton

The Nanophone: Sensing Sound with Nanoscale Spider Silk

Tue, Sep 26
Lewis 101
Farhad Farzbod
Department of Mechanical Engineering
University of Mississippi
Vibrations: from Periodic Structures to the Human Face
Tue, Oct 3
Lewis 101
John Thompson
Department of Physics and Aastronomy
University of Maine
Student Understanding at the Physics-Mathematics Interface
Tue, Oct 10
Lewis 101
Alex Yakovlev
Department of Electrical Engineering
University of Mississippi
Recent Developments on Graphene and Graphene Periodic Surfaces at Microwave and Terahertz Frequencies
Tue, Oct 17
Lewis 101
Jenny Ross
Department of Physics
University of Massachusetts — Amherst
Microtubule Biophysics
Fri, Oct 20
Lewis 101
Brian Daly
Department of Physics and Astronomy
Vassar College
Picosecond Ultrasonics: Nanoscale Imaging and GHz Surface Acoustic Wave Studies
Tue, Oct 31
Lewis 101
 
 
 
 
Tue, Nov 7
Lewis 101
Jake Bennett
Department of Physics
Carnegie Mellon University
The Belle II Detector
Tue, Nov 14
Lewis 101
Matthias Kaminski
Department of Physics and Aastronomy
University of Alabama
Gauge/Gravitational Holography — Strong Physics far from Equilibrium
Tue, Nov 21
Lewis 101
Thomas Turkey
Department of Nutrition
Virginia Tech
Continuing Advantages of a Vegetarian Diet
Tue, Nov 28
Lewis 101
Shaon Ghosh
Center for Gravitation, Cosmology and Astrophysics
University of Wisconsin — Milwaukee
Multi-Messenger Astronomy
Tue, Dec 05
Lewis 101
Final Exam Week  

This page has been viewed 32578 times.
The physics colloquium organizer is Katherine Dooley
This page is maintained by David Sanders
Latest update: Thursday, 21-Sep-2017 12:36:20 CDT

Past semesters: 

Abstracts of Talks


Department Faculty
Department of Physics and Astronomy
University of Mississippi

Introduction to Department Research, followed by Ice Cream Social.

3:00 PM — Society for Physics Students (SPS) greets new undergrads and gives tour of Lewis Hall
3:30 PM — Undergrad / Faculty Pizza Social
4:00 PM — Colloquium: Department Research Overview
4:30 PM — Grad Student / Faculty Ice Cream Social


Mike Reep and Scott Watkins
Department of Physics and Astronomy
University of Mississippi

Machine Shop Physics

Experimental physics depends on instrumentation made in the University of Mississippi's Physics machine shop. Instruments made for Acoustics, Atmospheric physics, Condensed Matter physics, and Particle physics will be shown.


Vahid Naderyan
Department of Physics and Astronomy
University of Mississippi

MEMS Microphones

MEMS (Micro-Electro-Mechanical Systems) microphones are acoustic sensors which translate sound waves to an electrical signal. Recent developments in MEMS technology have led to the development of very small size and high-performance microphones. Silicon fabrication creates the MEMS elements with the geometries of the order of microns. Due to their small size and high performance, MEMS microphones are used in mobile phones, hearing aids, “Internet of Things” devices, small electronic devices, etc. In this talk, I will explain the basic principles of the capacitive MEMS microphones and will talk about the Acoustical, Mechanical, and Electrical domains in a MEMS microphone and their connections.


Ron Miles
Department of Mechanical Engineering
State University New York — Binghamton

The Nanophone: Sensing Sound with Nanoscale Spider Silk

Hundreds of millions of years of evolution resulted in hair-based flow sensors in terrestrial arthropods that stand out among the most sensitive biological sensors known. These tiny sensory hairs can move with a velocity close to that of the surrounding air at frequencies near their mechanical resonance, in spite of the low viscosity and low density of air. No man-made technology to date demonstrates comparable efficiency. Here we show that nanodimensional spider silk captures fluctuating airflow with maximum physical efficiency (Vsilk/Vair ≈1) from 1Hz to 50kHz, providing an unparalleled means for miniaturized flow sensing. Our mathematical model shows excellent agreement with experimental results for silk with various diameters: 500nm, 1.6µm, 3µm. When a fiber is sufficiently thin, it can move with the medium flow perfectly due to the domination of forces applied to it by the medium over those associated with its mechanical properties. By modifying a spider silk to be conductive and transducing its motion using electromagnetic induction, we demonstrate a miniature, directional, broadband, passive, low cost approach to detect airflow with full fidelity over a frequency bandwidth that easily spans the full range of human hearing, as well as other mammals, birds, amphibians, and reptiles.


Farhad Farzbod
Department of Mechanical Engineering
University of Mississippi

Vibrations: from Periodic Structures to the Human Face

This talk covers four different and yet connected subjects; Resonant Ultrasound Spectroscopy (RUS), vibration analysis of periodic structures, and using facial vibrations in wearable computers. RUS is a technique to characterize the elastic and anelastic properties of materials. It is based on the measurements of the vibration eigenmodes of a sample with simple geometry such as a parallelepiped. In Laser RUS, the excitation part is done by a pulsed laser, generating thermoelastically excited ultrasonic pulse. In the detection side, a photorefractive interferometer is used to detect ultrasound. Measured eigenmodes along with eigenfrequencies reveal much information with regard to micro-structural state of the sample material. Novel techniques/problems in laser RUS is discussed in this section. In the second part, periodic structures are discussed. In periodic lattice structures, analysis of wave propagation to uncover dispersion relationships can be greatly simplified by invoking the Floquet-Bloch theorem. The accompanying Bloch formalism, which was first introduced for the study of quantum mechanics and has been borrowed in structural analysis, allows a system's degrees of freedom to be reduced to a small subset contained in a single unit cell. When this is combined with the finite element method, the result is a powerful framework for analyzing wave propagation and dispersion in complex media. In this section, among other things, the manner in which damping affects dispersion is talked about. In the next part, I talk about reciprocity in acoustics and how to break it; one way to break time reversal symmetry is to have a moving wave propagation medium. If the acoustic wave vector and the moving fluid velocity are collinear, we can use the wave vector shift caused by the fluid flow to break reciprocity. An alternative approach we have taken, is to use a fluid velocity field which enters the differential equation of the system as a cross product term with the wave vector. In the final part, bone conduction hearing is discussed; how it helps hearing and how it can be utilized for better communications in wearable technologies.