Sina Rostami successfully defended his PhD prospectus titled "The characterization of radiation forces in the near field of ultrasonic beams".  Sina's research advisor is Dr. Joel Mobley.

Nate Hill successfully defended his PhD dissertation titled "Characterization of Vibrational Response of a Helical Coil Subject to Environmental Exposure and Structural Modifications".  Dr. Joel Mobley was Nate's research advisor.

Claudia Chambliss, one of our undergraduate researchers, graduated and was accepted into the Cornell biophysics program.  Dr. Cecille Labuda was Claudia's research advisor.

Scott Chumley defended his honors thesis on the characterization of the mechanical response of helical antennas for satellite communication.  Scott's research was directed by Dr. Joel Mobley.  Scott has completed his BS in Physics and will go on to graduate school at the University of Alabama Birmingham.

Claudia Chambliss, our newest member of the group, gave a poster on her research involving the ultrasonic properties of white and gray matter in mammalian brain.

The Acoustical Society of America's 179th meeting was virtual (Acoustics Virtually Everywhere).  Cecille Labuda presented a talk on work involving the ultrasonic properties of mammalian brain that she has been working on with some collaborators at the meeting and contributed to a second presented talk.

• Labuda C, Newman WR and Hoffmeister BK.  Parametric imaging of ultrasonic backscatter of fixed sheep brain.  The Journal of the Acoustical Society of America 148, 2774 (2020); https://doi.org/10.1121/1.5147723
• Newman WR, Labuda C and Hoffmeister BK.  Spatial variation of ultrasonic attenuation and speed of sound in brain tissue visualized by parametric imaging The Journal of the Acoustical Society of America 148, 2774 (2020); https://doi.org/10.1121/1.5147722

Cecille Labuda gave a talk at the July 20 - 23 Ultrasonics 2020 conference.  The talk title was "Development of a Tissue-Mimicking Phantom of the Brain for Ultrasonic Studies".  The conference is usually held in Lisbon, Portugal but moved to remote on Zoom due to the covid-19 pandemic.

A paper titled "Thermal property and shear wave speed indicators of phase transitions in a micellar fluid" has been accepted for publication in the Journal of the Acoustical Society of America Express Letters.  The paper is authored by E.G. Sunethra K. Dayavansha and Cecille Labuda.  https://doi.org/10.1121/10.0000945

Dr. Joel Mobley was elected a 2019 Fellow of the Acoustical Society of America for contributions to the ultrasonic characterization of dispersive systems.

Fellowship in the Acoustical Society of America is an honor.  An ASA fellow is deemed to be in the top 10% of the membership of the Technical Committee in his or her chosen area of interest.

Election to fellowship depends on several factors.  These include technical contributions to acoustics as evidenced by publications and presentations, patents, projects, service to the Society, participation in Society activities, contributions to the teaching or dissemination of knowledge of acoustics, leadership activities in other acoustical societies and Standards activities.

Dr. Joel Mobley is Professor of Physics and Astronomy at the University of Mississippi and Senior Scientist at the National Center for Physical Acoustics at the University of Mississippu.

A paper titled "Broadband wave packet dynamics of minimally diffractive ultrasonic fields from axicon and stepped fraxicon lenses" has been accepted for publication in the Journal of the Acoustical Society of America in June 2019. The paper is authored by Robert Lirette and Joel Mobley.  https://doi.org/10.1121/1.5116011

Bobby Lirette has successfully defended his PhD dissertation.  His work involved the design of fraxicon and Fresnel lenses to manipulate ultrasound beams to increasing their focal power efficiency and use them to extract droplets between fluid-fluid interfaces.

Several people in the group will be giving talks at the upcoming 177th Meeting of the Acoustical Society of America.  The talks are listed below.

• Droplet extraction and manipulation at a fluid interface using fraxicon modified ultrasound. Robert L. Lirette, Joel Mobley and Likun Zhang.
• Focal power efficiencies achieved with aluminum Fresnel and fraxicon low-profile lenses. Robert L. Lirette and Joel Mobley.
• Development of vibrational metrics for internal damage scenarios of a scaled transnuclear-32 dry storage cask for spent nuclear fuel. Kevin Y. Lin, Joel Mobley, Wayne E. Prather, Zhiqu Lu, Gautam Priyadarshan, and Josh R. Gladden.
• Graduate study in physical acoustics at the University of Mississippi. Joel Mobley, Josh R. Gladden, Cecille Labuda and Likun Zhang.

A paper titled "Development of a Tissue-Mimicking Phantom of the Brain for Ultrasonic Studies" has been accepted for publication in Ultrasound in Medicine Biology on August 17 2018.  The paper is authored by Somayeh Taghizadeh, Cecille Labuda and Joel Mobley.

Three of the graduate students in the group defended their dissertations and theses during the summer of 2018.  Sunethra Dayavansha earned her PhD left to take a postdoctoral position in Cincinnati. Ukesh Koju earned his PhD and moved to Oregon.  Somayeh Taghizadeh earned her master's degree and left to start a medical physics PhD in Arizona.  We wish all our new graduates the best in their new positions.

The 174th Meeting of the Acoustical Society of America is taking place in New Orleans, LA from December 4 - 9 2017.  Joel Mobley is the chair of the organizing committee with Cecille Labuda and Likun Zhang as committee members.

Several students in the group are giving talks at the meeting.  A list of talks given by people in the research group are as follows.

• E. G. Sunethra K. Dayavansha, Cecille Labuda, and Joel Mobley.  "Temperature and frequency dependent behavior of high intensity focused ultrasound (HIFU)-induced shear waves in a viscoelastic micellar fluid."
• Kevin Y. Lin, Wayne E. Prather, Zhiqu Lu, Joel Mobley, and Josh R. Gladden.  "Vibrometric characterization of a TN-32 dry storage cask for spent nuclear fuel."
• Kevin Y. Lin, Wayne E. Prather, Zhiqu Lu, Joel Mobley, and Josh R. Gladden.  "The determination of mode shapes of a scaled model TN-32 spent nuclear fuel dry storage cask."
• Robert L. Lirette and Joel Mobley.  "Focal zone characteristics of stepped Fresnel and axicon acoustic lenses."
• Somayeh Taghizadeh, Cecille Labuda, and Joel Mobley.   "Development of tissue-mimicking phantom of the brain for ultrasonic studies."
• Likun Zhang, Joel Mobley, Xue Jiang and Yong Li.  "Metamaterial-based passive phased arrays: Resolution, losses, and characterization."

Joel Mobley and Ukesh Koju attended the ASA Boston meeting.  Ukesh gave a talk on phononic crystals at the meeting.

Sunethra Dayavansh, Ukesh Koju and Somayeh Taghizadeh gave talks at the Mississippi Academy of Sciences 2017 conference in the Physics and Engineering Division.  Somayeh also gave a poster presentation and won second prize from a field of more than 100 posters.

Three of our graduate students, Sunethra Dayavansha, Ukesh Koju and Somayeh Taghizadeh will give talks on their research in the UM Department of Physics colloquium on Februrary 14.  Sunethra will talk about her work on micellar fluids, Ukesh will talk about his work on metamaterials and Somayeh will talk about her worn on development of tissue-mimicking phantoms.

Somayeh Taghizadeh and Sunethra Dayavansha participated in the University of Mississippi 3 Minute Thesis talks.  Somayeh and Somayeh gave condensed talks about their research.  Somayeh works on tissue phantom development and Sunethra works on shear wave studies.

The National Center for Physical Acoustics, where our Ultrasonics Laboratory is located, celebrated its 30th anniversay on Friday October 14.  To celebrate this remarkable milestone, an open house was held at NCPA with tours of the lab and acoustic demos.  The Ultrasonics group put on two demos, the flame tube and the acoustic fountain.

Here, Cecille Labuda demonstrates standing waves on a flame tube.

Visitors see sound waves in flame at the open house and demonstrations at the 30th anniversary celebration at NCPA. Photo by Kevin Bain/Ole Miss Communications

Ukesh Koju demonstrates the acoustic fountain using a high intensity focused ultrasound transducer.

Ukesh Koju, a ph.D. student in Physics, shows what sound can do to water during the open house at the NCPA's 30th anniversary celebration. Photo by Kevin Bain/Ole Miss Communications

To celebrate the 30th anniversary of the National Center for Physical Acoustics, a luncheon followed by an open house will be held this Friday October 14.  Acoustics demos will be put on by various research groups during the open house.  The Ultrasonics group will put on several demos including the acoustic fountain, Rijke tube and flame tube.  All are invited to attend.  A description of the event can be found here.

Sunethra Dayavansha, Ukesh Koju and Somayeh Taghizadeh gave talks in the PGSA Symposium held in Lewis Hall at the University of Mississippi.  The students reported on their recent research.

Sunethra discussed shear waves in micellar fluids, Ukesh discussed metamaterials and Somayeh discussed development of brain tissue-mimicking phantoms.  The symposium was organized by the Physics Graduate Student Association.

Nazanin Omidi earned her MS during the summer of 2016 and is leaving the group to take up and internship.  We wish Nazanin well and will miss her as she was one of the integral members of the ultrasonics group.

Nazanin Omidi and Sunethra Dayavansha gave a tak on kinetic and potential energy in the Girls STEM Camp held in the School of Engineering at the University of Mississippi.  The camp is held annually for girls in grades 6 - 8 and is run by Tiffany Gray.

Nazanin Omidi successfully defended her MS thesis on Computation of Ultrasonics Fields in Feline Brain.  Nazanin was advised by Charles C. Church and Cecille Labuda and Joel Mobley was one her thesis committee.  She recently gave a talk on her thesis research at the Acoustical Society of America meeting in Utah.

Joel Mobley will give a lecture on Acoustic Metamaterials and Dispersive Media at the 2016 Physical Acoustics Summer School (PASS).  Kevin Lin will be a student participant.  PASS 2016 starts June 16 and ends June 21.  The schedule of lectures may be found here.

Cecille Labuda gave an introduction to waves at the "Waves, Here, There and Everywhere" workshop for teachers.  The workshop was organized by UM Physics LIGO group in collaboration with the UM Center for Math education.  The workshop concludes with a tour of the National Center for Physical Acoustics.

Sunethra Dayanvansha successfully defended her PhD prospectus on June 1.  She will study the propagation of acoustic waves through micellar fluids.

The Acoustical Society of America is livestreaming some of its sessions.  Stream links can be found here: http://acousticalsociety.org/content/streaming-broadcast.  Nazanin Omidi will be giving a talk in the Focused Ultrasound for Brain Treatment session.  That stream can be found here at the appropriate time (2:00 pm local in Utah): https://attendee.gotowebinar.com/register/5481891571892706306

Cecille Labuda will give a talk on acoustics at the UM Women in STEM Spring Dinner to be held on the University of Mississippi campus on April 21.  Kate Dooley, another of the UM Physics faculty will also give a talk on gravitational waves. The talk is titled "Ultrasound: The Sound That You Can't Hear".

Joel Mobley gave a fun-filled Science Cafe on the physics of MRI.  He used several demos to explain magnetic spin, the response of protons in the body to resonant magnetic fields and how MRI collects and manipulates data.

Nazanin Omidi will give a talk at the 171st Acoustical Society of America meeting in Salt Lake City Utah.  The meeting will be this upcoming May 2016.

Nazanin Omidi, Cecille Labuda, Charles C. Church.  Computation of Ultrasonic Pressure Fields in Feline Brain​.

In 1975, Dunn et al. (JASA 58:512-514) showed that a simple relation describes the ultrasonic threshold for cavitation–induced changes in the mammalian brain. The thresholds for tissue damage were estimated for a variety of acoustic parameters in exposed feline brain. The goal of this study was to improve the estimates for acoustic pressures and intensities present in vivo during experimental exposures rather than estimating them using linear theory. In our current project, the acoustic pressure waveforms produced in the brains of anesthetized felines were numerically simulated for a spherically focused, nominally f1-transducer (focal length = 13 cm) at increasing values of the source pressure at frequencies of 1, 3, and 9 MHz. The corresponding focal intensities were correlated with the experimental data of Dunn et al. The focal pressure waveforms were also computed at the location of the true maximum. For low source pressures, the computed waveforms were the same as those determined using linear theory, and the focal intensities matched experimentally determined values. For higher source pressures, the focal pressure waveforms became increasingly distorted; similar results were obtained with increasing frequency.

Joel Mobley will give a Science Cafe on March 22 on the physics of magnetic resonance imaging.  The Science Cafe will be held at Lusa Bakery Bistro and Bar, 1120 North Lamar Blvd, Oxford.  The Oxford Science Cafe website can be found here: https://www.phy.olemiss.edu/oxfordsciencecafe/

Abstract

Magnetic Resonance Imaging (MRI) has revolutionized the diagnosis and treatment of a broad spectrum of medical conditions. Since its clinical debut in the 1980’s, it has evolved to provide a level of anatomical detail not possible with any other imaging modality, all without the focus of an ultrasound probe or the directionality of an x-ray beam. The fundamental principles at work in MRI include quantum physics, spinning tops, flipping magnets and simple patterns of bright and dark. The aim of this talk is to remove some of the mystery of how the manipulation of the weakest magnets in the atom leads to the MR image and to look at emerging medical treatments enabled by MRI.

Sunethra's paper titled "Temperature Dependence of Shear Wave Speed in a Micellar Fluid" was accepted for publication in Proceedings on Meetings in Acoustics (POMA).

Three of our graduate students will give talks in the University of Mississippi Physics Graduate Student Association (PGSA) Symposium to be held this Saturday February 27.  Ukesh is one of the main organizers of the symposium.  The talks are described below.

• Sunethra Dayansha et al.  Temperature Dependence of Shear Wave Speed in a Viscoelastic Micellar Fluid.
• Ukesh Koju et al. Propagation of Pulsed Ultrasonic Fields in a Band Gap of a Two Dimensional Phononic Crystal.
• Kevin Lin et al.  Multimodal Nondestructive Dry Cask Basket Structure and Spent-Fuel Evaluation - Initial Stage Simulation.​​

Three of our students, Ukesh Koju, Nazanin Omidi and Sunethra Dayavansha attended the MAS meeting and gave talks and posters at the meeting. Here they are at the meeting. 

Nazanin Omidi was the fourth place winner in the Mississippi Academy of Sciences poster competition. Nazanin also participated in the Mississippi IDeA Network of Biomedical Research Excellence (INBRE) symposium.

Participation in the competition was by invitation.

Nazanin Omidi was selected as one of 50 students to participate in the Mississippi Idea Network of Biomedical Research Excellence (INBRE) Symposium at the Mississippi Academy of Sciences (MAS) annual meeting to be held from February 18 - 19 2016 in Hattiesburg, Mississippi.  The students will compete for top presentation prizes in the symposium.  Two of the other students in the group, Sunethra Dayavansha and Ukesh Koju will also be giving talks at the meeting.