Final Report

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Dr. Brian Anderson, Department of Physical and Mathematical Science

How well the academic objectives of the proposed research were met, along with a description of the results and findings of the project

The proposed project was to study three potential uses of time reversal acoustics to obtain preliminary results that might lead to external funding. These three uses were 1. Targeted speech communications for hostage rescue and covert operations, 2. A means of delivering opposite phase sound for active noise control, and 3. To provide a means to study large amplitude, nonlinear sound from a controlled source. I will now discuss how each area is panning out:

1. Targeted speech communications – Michael Denison, a graduate student has done the bulk of the work in this research. William Black and Joel Temple, both undergraduate students have also helped with this work. Michael has been conducting a numerical modeling study to determine the quality of the focused speech using time reversal by determining how many loudspeakers are needed depending on the room in which we wish to provide targeted speech. His work has been presented at a BYU Student Research Conference and will be presented at an international meeting of the Acoustical Society of America in May 2018 in Minneapolis, Minnesota. Michael’s work is similar to previous work that others have done but it has uncovered some significant limitations in the applicability of the results done by others. Michael’s work will be written up and submitted for peer review journal articles this summer as he finished up his Master of Science degree. Michael’s work has laid the foundation for a proposal that is currently being written in collaboration with Los Alamos National Laboratory and has a high chance of being awarded through a subcontract to BYU.
2. Active noise control – Trent Furlong, an undergraduate student, has been leading this research effort. Trent was a new student to research near the start of this MEG. His work has been presented at a BYU Student Research Conference and it will be presented at an internal meeting of the Acoustical Society of America in May 2018 in Minneapolis, Minnesota. His work started from ground level with no prior work done in this area and so it took time to get Trent up to speed and to start producing results. We have submitted 2 proposals for National Institute of Health funding on this topic. The first proposal made it to the final round of reviews and it was ranked, but unfortunately not funded. We spoke with the funding officer and received some great feedback. We resubmitted our proposal and the second time around it did not make it to the final round of reviews, even though we felt the proposal was much stronger. We are preparing a proposal to submit in Feb. 2018 that includes Trent’s most relevant results, which we feel will make the proposal as strong as it can be. Trent’s work has shown that it is indeed possible to use time reversal acoustics to deliver an active noise control signal. His research has focused on the scope of applicability of time reversal. He has very recently been conducting proof of concept experiments in the BYU MRI facility and these results are promising. We plan to write up Trent’s work and submit it for a peer reviewed journal article.
3. Large amplitude focusing – Miles Clemens, a graduate student, Matthew Willardson, an undergraduate student, and most recently Brian Patchett, a graduate student have been working on this topic. Miles work led to a peer reviewed journal publication, an international conference presentation, and a BYU Student Research Conference presentation before he decided to switch research areas. Matthew completed a senior thesis on this topic and has done the bulk of the research. Matthew has presented his research at an international conference and at the BYU Student Research Conference. Matthew’s research resulted in the development of some significant ways in which to greatly increase the amplitude of time reversal focusing and his work is currently under peer review for the Journal of the Acoustical Society of America. Matthew’s research has led to surprising results that were not expected and provides a new area of study that Brian Patchett has now taken over to explore. It was only recently that we were able to do the crowning experiments and see how loud the 2 focusing could be. We then determined that our equipment was not adequate to measure the actual loudness. Brian has found new sensors that we will be using shortly. These results should be very applicable to understanding how blast waves travel and it could provide a very different kind of tool than what is currently available to study the impact of blast waves on hearing protection of soldiers. We plan to submit research proposals to the U.S. Army and possibly the National Science Foundation. Sarah Young and Christopher Heaton have done very related research with elastic waves in solid media and the applications we study in this area have benefitted from this research as well, publishing a peer reviewed journal article on their work.

In total 2 peer reviewed journal articles have been published with another paper currently under review from work conducted for this MEG project and several more papers are planned to be submitted for peer review this year. Additionally, 13 presentations have been given at international conferences, university colloquia, and at the BYU Student Research Conference. Two proposals have been submitted based on the results and several more are planned to be submitted from each of the three areas studied.

Evaluation of the mentoring environment

The mentoring experience provided by this MEG helped to develop student researchers in a meaningful way, which is perhaps the biggest impact of this funding. This was new research conducted at BYU, rather than the continuation of existing work, so it took some time to get experiments setup and obtain results that can lead to papers and proposals for funding. The students learned practical research skills and they made meaningful contributions to it. Matthew is now in a graduate program at the University of Pennsylvania, Christopher is running his own pest control business in Colorado, and the other students are continuing their studies with future plans for graduate school or for jobs they hope to get this year.

List of students who participated and academic deliverables (including anticipated)

The following individuals participated in this research during the grant period (only dates from Jan 2016 – Dec 2017 are shown):

Undergraduate students:

  • Matthew Willardson (Jan. 2016 – Aug. 2017)
  • Trent Furlong (Mar. 2016 – Dec. 2017)
  • William Black (Jan. 2016 – Apr. 2016)
  • Joel Temple (Apr. 2016 – Sep. 2016)
  • Christopher Heaton (Jan. 2016 – Jun. 2016)
  • Paige Simpson (Sep. 2017 – Dec. 2017)

Graduate students:

  • Sarah Young (Jan. 2016 – Dec. 2017)
  • Miles Clemens (Jan. 2016 – Jun. 2016)
  • Michael Denison (Aug. 2016 – Dec. 2017)
  • Brian Patchett (Aug. 2017 – Dec. 2017)

The following academic deliverables were achieved during the grant period: (student co-authors marked with an asterisk)

Publications:

3) M. L. Willardson, B. E. Anderson, S. M. Young, and M. H. Denison, “Time reversal focusing of high amplitude sound in a reverberation chamber,” J. Acoust. Soc. Am., under review.
2)* B. E. Anderson, M. Clemens, and M. L. Willardson, “The effect of transducer directionality on time reversal focusing,” J. Acoust. Soc. Am. 142(1), EL95-El101 (2017). http://dx.doi.org/10.1121/1.4994688
1)* C. Heaton, B. E. Anderson, and S. M. Young, “Time reversal focusing of elastic waves in plates for educational demonstration purposes,” J. Acoust. Soc. Am. 141(2), 1084-1092 (2017). http://dx.doi.org/10.1121/1.4976070

Undergraduate senior theses which included work from the grant period:
1. Christopher Heaton – “Time reversal focusing of elastic waves in plates for educational demonstration purposes”, Aug. 2016.
2. Matthew Willardson – “Time reversal focusing of high amplitude sound in a reverberation chamber”, Aug. 2017.

Conference talks given by students which included work from the grant period: (student co-authors marked with an asterisk)

13) B. E. Anderson, “Focused acoustic energy through time reversal,” Utah Valley University Physics Department Colloquium, Nov. 2017. Invited Talk.
12) S. Young* and B. E. Anderson, “Optimization of time reversal focusing in a resonant system through various signal processing techniques,” Qual. Rev. of Nondestruct. Eval., (2017).
11) M. L. Willardson* and B. E. Anderson, “Optimization of time reversal focusing in a reverberation chamber,” Brigham Young University Student Research Conference, Provo UT, Mar. 2017.
10) S. Young* and B. E. Anderson, “Optimization of time reversal focusing in elastic media,” Brigham Young University Student Research Conference, Provo UT, Mar. 2017.
9) M. Denison* and B. E. Anderson, “Understanding the effect of room parameters on acoustic time reversal,” Brigham Young University Student Research Conference, Provo UT, Mar. 2017.
8) T. Furlong* and B. E. Anderson, “Using time reversal focusing for active control of magnetic resonance imaging noise,” Brigham Young University Student Research Conference, Provo UT, Mar. 2017.
7) S. Young*, M. L. Willardson*, M. Denison*, T. Furlong*, and B. E. Anderson, “Optimization of time reversal focusing in resonant and non-resonant systems through various signal processing techniques,” J. Acoust. Soc. Am. 141(5), 3906 (2017).
6) S. M. Young*, C. Heaton*, and B. E. Anderson, “’Knocked Over!’: Demonstration of time reversal focusing using bending waves in a thin plate,” J. Acoust. Soc. Am. 139(4), 2083 (2016). 4
5) M. L. Williardson*, M. Clemens*, and B. E. Anderson, “Use of time reversal focusing to create a high amplitude focus of sound in air,” J. Acoust. Soc. Am. 139(4), 2083 (2016).
4) M. Clemens*, M. Williardson*, and B. E. Anderson, “The effect of transducer directivity on properties of time reversal focusing,” J. Acoust. Soc. Am. 139(4), 2083 (2016).
3) B. E. Anderson, “Time reversal for energy focusing in fluid and elastic media,” Idaho State University, Physics Department Colloquium, Apr. 2016. Invited Talk.
2) B. E. Anderson, “Time reversal for energy focusing in fluid and elastic media,” The Pennsylvania State University, Center for Acoustics and Vibration Seminar, Apr. 2016. Invited Talk.
1) M. Clemens* and B. E. Anderson, “The effect of transducer directivity on properties of time reversal focusing,” Brigham Young University Student Research Conference, Provo UT, Mar. 2016.

Description of how the budget was spent

The budget was originally allocated as follows:

Undergrad research $8,000
Graduate research $10,000
Supplies $2,000

Since the College of Physical and Mathematical Sciences greatly expanded their support of undergraduate student research, I ended up using more of the money to support graduate students than proposed and less spent on undergraduates. Also, I spent more money than $2,028 on the supplies used but I used startup funds to supplement the rest of the cost of those supplies. Here are the details on the spent funds:

Undergrad research in 2016 $1,118
Graduate research in 2016 $7,100
Supplies in 2016 $2,028
Undergrad research in 2017 $2,654
Graduate research in 2017 $7,100
Supplies in 2017 $0
Total $20,000

The funds in the undergrad research category were used to support these students as research assistants either partially or fully during the grant period (many of the students listed previously were supported by other sources of funding):

Undergraduate students:

  •  Matthew Willardson (Jan. 2016 – Aug. 2017)
  • Trent Furlong (Mar. 2016 – Dec. 2017)

Graduate students:

  • Miles Clemens (Jan. 2016 – Jun. 2016)
  • Michael Denison (Aug. 2016 – Dec. 2017)

The funds in the Supplies category were used to pay for loudspeakers and cables.