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In footnotes or endnotes please cite AIP interviews like this:
Interview of Mack Breazeale by Henry E. Bass on 2007 August 9,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Mack Breazeale has been an active member of the Acoustical Society of America and the IEEE almost his entire career. He was born August 15, 1930 in a mining community in Virginia. He later moved to a small town in Tennessee near the current Oak Ridge Laboratory. From there he attended undergraduate school at Berea College and received his Masters from the University of Missouri where he began his studies of ultrasound in liquids. He then studied with Professor Hiedemann at Michigan State. There he continued his studies of ultrasound in liquids. At Michigan State he studied with Bill Cooke and Walter Meyer who went on to recognition in acoustics. He then spent a year on a Fulbright Fellowship in Germany with Professor Kneser. Soon after his return he accepted a position at the University of Tennessee where he spent much of his career studying nonlinear properties of solids. During his time at the University of Tennessee, he directed theses and dissertations of about 50 graduate students. In 1988, he moved to the National Center for Physical Acoustics at the University of Mississippi where he has continued his studies of nonlinear properties of solids.
My name is Henry Bass. Today’s date is August 9th, 2007. We are at the National Center for Physical Acoustics in the University of Mississippi campus in the State of Mississippi, USA. The time is 14:00 hours, and I’m about to interview Mack Breazeale for the Acoustical Society of America Technical Committee on Physical Acoustics. First, Mack, what is your present address?
At present, my home address is 1035 Zilla Avent Drive, Oxford. And the NCPA address is University 38677.
What is your present telephone number?
My present telephone number at NCPA is 915-7490. The home telephone number is 234-4534.
Who is your present employer?
University of Mississippi.
What is their present business?
Whatever universities do.
Not much, probably, huh? [Chuckles] What is your job title?
Distinguished Research Professor of Physics.
How long have you been at the University of Mississippi?
What do you do here?
Okay. The next set of questions are Acoustical Society of America-related questions. Give your best answer. What year did you join the Acoustical Society of America?
What was your age and profession at that time?
I was 27 years old, and I was Assistant Professor of research at Michigan State.
What area of acoustics were you interested then?
Any special problems you were working on at that time?
We were working on non-linear acoustics.
Well, no, in liquids.
Who were you working with there?
I was working with Professor Hiedemann.
He was the same one who directed your dissertation.
What were your reasons for joining the Acoustical Society of America?
Actually, Hiedemann recommended that.
So he was one who encouraged you to join.
Yes, he had coached me.
And what rational did he give?
He suggested that the Acoustical Society was the most important society for our interest.
What ASA committees were you or are you a member of?
I’ve been a member of education committee, the membership committee, and the physical acoustics committee.
Have you held any offices in the ASA?
I was associate editor of the journal for 21 years.
Wow. When was that?
That was ended in 2001, I think.
So you went all the way back to Bruce Lindsay’s era?
Is there any particular ASA meeting that stands out as being very special to you?
Probably, the Honolulu meeting of 1988. I was awarded the silver medal in physical acoustics at that time.
Where was the first meeting that you attended?
I don't remember exactly. I think it was the meeting in Rhode Island — Providence, Rhode Island.
Are there any other ASA members other than Professor Hiedemann who had a strong influence on your career?
Probably Floyd Dunn and Bruce Lindsay. Bruce, of course, appointed me as associate editor first.
Right. And what role did Floyd play?
Floyd is a respectable person.
He is. He truly is. Is there anything you would like to say about the acoustical society at past, present, or future?
Well, I think the journal is important, and the journal had Bruce Lindsay as editor-in-chief, and then Dan Martin, and currently, it’s Al Pierce.
How about the interaction within the society? Do you care to comment on that?
There has to be an interaction and a stimulation for research that comes from the interaction.
What other professional organizations do you belong to?
American Physical Society, The American Association of University Professors, and the IEEE.
How would you compare the IEEE meetings to ASA meetings?
The IEEE meetings are more specialized. They are devoted more specifically to certain aspects of acoustics, and the ASA meetings are more generalized and more university-oriented, I think.
Is the number of people who attend the meetings about the same?
About the same. I think we had about 700 at meetings of the IEEE, and probably an equal number at the ASA.
Have you provided an oral history interview for any other organization?
No, I haven’t; this is it.
Let’s go back and talk about some of your early history. I’ll tax your memory here and see where you fail or pass. When and where were you born?
I was born August 15th, 1930, in Leona Mines, Virginia. It no longer exists.
What did your parents do?
My father was a coal miner.
Oh, is that right. So do you watch some of these things that are taking place with the problems that the coal miners have with the collapses?
I watch them, but they can’t do much about them.
Can you identify with them?
I can identify with the complaints. Oh, yeah.
Before you entered college, other than Virginia, where did you live?
I lived in Wheat, Tennessee, and I was a Cumberland Homesteader. Wheat, Tennessee no longer exists, either. It’s now called Oak Ridge.
So you lived there before it was Oak Ridge?
Yes, that’s right.
Were you there when they started construction of Oak Ridge?
We had gone to the homesteads by that time.
You went where?
The Cumberland Homesteads. It’s at Crossville.
Oh, okay. So you moved away from the Oak Ridge area?
That’s right. We moved probably 50 miles away.
And did you go to high school there?
I went to high school in Cumberland County, yes.
How would you describe yourself during those early years?
Probably the best description is rural. I had lots of time to myself.
Did you enjoy anything special like reading or sports?
I enjoyed hunting, yes, and I had a special dog.
When you were young, what did you want to be when you grew up?
I don't remember anything that I wanted to be.
When you moved to Cumberland, was your father still in the mining business?
My father was not in the mining business. He became a stonemason.
Before college, what kind of hobbies did you have other than hunting?
Hunting and fishing.
Did you have any heroes — sports heroes or other heroes — that you remember?
I don't remember any of them.
Was church a big part of your family during that era?
It was a big part of my growing up, but looking back, I think I can remember the principal of the high school, B. M. Carr, and Ms. Lowe was one of the grade school teachers, and Mrs. Byrd was very influential; she was the principal of the junior high that I attended.
What activities, subjects, and things did you enjoy most in high school?
Probably geography and science in general.
Did they offer physics in high school?
So did they have physical science or chemistry?
Physical science, yes.
How about chemistry?
I think chemistry was offered, too.
Did you have any particularly good teachers for those courses, as you remember?
No, I remember the teacher of typing. She’s the only one who gave me a C.
Let’s go on and talk about your college years. First of all, the undergraduate level. Where did you first go to college?
I went to Berea College in Kentucky.
It was a matter of expense.
Was it nearest where you lived?
It was 200 miles away.
So the expense was tuition, things like that, that was cheaper?
That’s right. There was no tuition.
Oh, that’s a pretty good deal. Even for out-of-state students?
That’s true. There’s no tuition today.
How do they stay in existence?
Well, I guess that’s one way to do it. What was your major when you first started?
How did you choose physics, having never had a physics course up to that point?
Well, I probably chose it because of the logic of physics.
How did you know of the logic of physics if you never had a physics course?
Well, I listened to Waldemar Noll. He was the head of the physics department at Berea.
When you went there, though, you signed up for physics before you ever met him, didn’t you?
So you probably met him before you declared physics as a major. That’s interesting.
Probably, I declared physics because of one of my colleagues.
The colleague might have known more about what physics was?
I think he may have.
How was your math preparation in high school? Were you ready for physics?
I was ready for physics, yes. Preparation for math in high school was not exceptional, but when I got to Berea, there was a good math department and a wise head of the math department. I never had calculus, because I studied it one summer, and in the fall, I skipped calculus and went on beyond calculus.
So you just went right to differential equations?
As an undergraduate, did you ever change your major?
No, it’s always been physics.
You know it’s not unusual. Students who end up majoring in physics most often start up in physics. Some transfer out, but not a lot of them transfer in. I’m not sure why. As an undergraduate, did you belong to any special clubs or participate in any special school activities?
Yes, I belonged to the math club, and I was a member of the choir, and a few things like that.
Did they have a physics club — Sigma Pi Sigma, or anything like that?
Yes, we had Sigma Pi Sigma, and I was member of that.
Tell us something about your undergraduate days. Was there a particular person or particular professor or particular event that really stands out?
Probably Dr. Noll in the physics department stands out, and Rude Osolnik stands out. He was a machinist, or he was in the woodworking shop, and I learned woodworking from him. And probably the most intellectually challenging person was Dr. Ross.
Was woodworking shop part of the physics department?
So how did you get to know him?
I needed a job, and so I worked in the woodworking shop for several years, and learned woodworking at that time.
How many students were there in the physics department?
There were probably eight.
In one class or all together?
So it was pretty much a small group; you knew everyone?
How many professors?
Usually one or two.
Has it changed much? Has the college grown? Do you get a chance to go back?
The enrollment has been kept at around 1500, which I think is wise. There is a selection process for freshmen entering, and that selection process would rule out all of my children.
Why is that?
I earn too much money.
Being from a small town in Tennessee, how did you even learn of it?
My sister went to Berea and my brother went to Berea, so I learned of it through them.
Great. During the period of your life when you were at the undergraduate level, were there any other particular heroes or role models that you can remember?
I don't remember any.
So you didn’t fall in love with the idea of Albert Einstein or anything like that?
No, Albert was young at that time.
Did you participate in any political activities — any rallies? Did you march up and down the road for any reason?
No, I didn’t. I marched up and down, but it was usually as part of the choir.
Looking back, considering your resources available to you, and considering where you’re from, would you have made the same choice?
How about physics? Would you still have chosen physics?
Yes, definitely physics.
Good. Let’s go on and talk about graduate school. Did you go to the same school for a master’s and a Ph.D.?
No, as a matter of fact, there’s no master’s program at Berea, so I had to change to another college for a master’s, and I went to the University of Missouri at Rolla.
But you went to get your Ph.D. at a different University after that, so you went to three?
That’s right. The University of Missouri at Rolla at that time only offered a master’s degree, and so at the end of the master’s degree, I had to change institutions again.
What made you choose the University of Missouri at Rolla?
But there were lots of schools, and you probably could have applied many places.
Well, I probably could have applied to a number of places, but when I found a definite offer of an assistantship, there was no point in it.
Did anyone at Berea College influence that application or steer you in that direction?
Dr. Noll probably was in contact with Dr. Fuller at Missouri.
And you say you got an assistantship, was that a teaching assistantship, a research assistantship?
Teaching assistantship, yes.
So you taught physics labs?
How long did that take?
I got my master’s in a year.
Wow, so you didn’t stretch it out at all. That must have meant that you were quite well prepared when you got to Rolla.
I probably was.
So the undergraduate education you received was pretty strong.
And the math training was sufficient so that I could handle the mathematics.
So after that you went on beyond that. Did you do a master’s thesis, or just a non-thesis master’s?
I did a master’s thesis, and I started the investigation of ultrasound at the University of Missouri at Rolla.
Oh, did you? Did they have a professor there who was interested in that topic?
Dr. Fuller was interested in the topic, but he was actually a nuclear physicist, so I was pretty much on my own.
Sometimes, that’s better. You know the University of Missouri still has a fairly strong history in nuclear physics and reactor physics and things like that. That’s sort of a continuing theme for them. So do you remember the title of your master’s thesis?
Someplace, I’ve written it down. Well, I remember the subject, anyway. It was “The Velocity of Ultrasound in Fluids”.
Water. At that time, not too many fluids had been examined.
Right. Well you know, at that time, I don't think sonar had come into significant use. It came into use at World War II, yeah?
The research was going on for sonar, yeah.
Who else at the University of Missouri had a big influence on your career and your life other than Professor Fuller?
I think Fuller has had the most influence. Dr. Lund was a theoretical physicist that I remember.
Let’s go on now to the Ph.D. What college did you go through there?
I went to Michigan State.
What led you to choose Michigan State?
How did you meet him or know about him?
I knew his reputation before I knew him, but Dr. Hiedemann was director of research in Germany, and he had come after the Second World War to Michigan State, and so I joined him there.
Before you arrived there, you knew about him; you were familiar with his reputation?
Yes. He had published quite a number of papers, and he was in contact with Sir C. V. Raman, the Nobel Prize winner, who began research in the diffraction of light by ultrasound.
When you arrived in Michigan State, how were you supported there?
So he had research funds to do that?
What specific projects did you work on there?
I worked on the interaction of light with ultrasound, and we began research on the nonlinear acoustics at that time.
You say the interaction of light with ultrasound. Was this in fluids?
In fluids, yes.
And still in water, or did you go into other fluids at that time?
I investigated other fluids. I found that carbon tetrachloride is not a good fluid to investigate.
What was your doctoral thesis?
My doctoral thesis was “The Use of Light To Measure Sound Pressure Amplitudes”.
Who other than Professor Hiedemann had a strong influence on you at Michigan State?
I think Hiedemann was the most important person at Michigan State for me. Professor Meixner in the math department also was influential. Professor Meixner went back to Aachen. He was in Michigan State for two years, and I had gotten a number of math courses with him.
During the time Professor Hiedemann was at Michigan State, there were a number of individuals that went on to be big names in acoustics that graduated from Michigan State. Did you meet some of those, or are you familiar with some of those that continue with you in a career in acoustics?
I’m the fourth person that Hiedemann hired, and I know all of them.
Who are they?
Bill Cooke, Walter Meyer… Well, at least I remember those two. We had quite a large group of people in acoustics at Michigan State.
What other professors did you have in acoustics?
Was Logan Hargrove one of Hiedemann’s students?
Logan Hargrove, yes, as a matter of fact. He was there at the same time as I was.
Who else followed you? Do you recall? Wasn’t Kenny Gilbert there at one time?
I didn’t know Ken, but he was there, yes.
How about Ralph Goodman? Was he there?
No, but subsequently I met Ralph. Ralph was at Colorado State.
Was he? That was after he graduated, though. But didn’t he go to school at Michigan State, or was that University of Michigan?
It was University of Michigan.
Other academic activities. While you were a student, did you ever conduct any classes for the college or the university? Did you teach classes?
I taught at Missouri. I was the teaching assistant at Missouri, so I taught there. And probably at Michigan State, my primary interaction was instruction rather than teaching on a one-to-one basis.
So tutoring students on a one-to-one basis?
Let’s go into other topics that formed your background. Were you ever in the military?
Did you ever go to a technical or trade school?
No, I didn’t go to technical or trade school.
Let’s go on, then, to your professional career. After college, you said you stayed on after your Ph.D. at Michigan State?
Actually, I stayed on as research assistant professor at Michigan State, and the reason was I wanted a Fulbright Scholarship, and I knew that I couldn’t get one the year that I got my degree, and I applied the year I got my degree, and I was research assistant professor during the time I was waiting for the Fulbright.
Did you get a Fulbright?
I did, yes.
And so your next place of employment, then, was somewhere over in Europe?
Yeah, I went to Germany, and I learned German.
I’m sure you learned other things, too.
A few other things, yes.
But who did you work with while there?
Kneser, for those who are listening to this tape but aren’t familiar with him, was perhaps one of the best known people in physical acoustics at that time, and if not in Europe, maybe in the world. He was really a dominant figure at the time.
Yes, he was.
What kind of work did you do for Kneser?
I measured the attenuation of sound in hydrogen chloride.
Gaseous hydrogen chloride?
Liquid and gaseous.
Both of them?
I would change the temperature.
So he must have, perhaps, since you were American, considered you expendable?
Well, the apparatus was.
So was this an era when he was looking at relaxation in hydrogen chloride?
So he was measuring dispersion as a function of frequency?
As a matter of fact, we published some of my data. There was a publication with Kneser and Hans Bauer.
Hans Bauer was here for a while.
I knew him before he came here.
Great guy, smart guy.
Yes, he is.
Have you, by any chance, heard from him in the last decade?
I haven’t heard from him in the last decade. I assume that he’s still at Stuttgart, but he was not made professor at the technical university. A person from Goettingen was made professor. (Eisenmenger)
Last I heard from Hans has been probably a little bit more than ten years, and at the time, he was devoting much of his time to music. I don't know if you know he played with a fairly well-known band in Europe, and a fair amount of his time was music, but at the time, he didn’t say what the illness was, but he was quite sick; he was quite ill. I don't know what the problem was, but he was very down at the time. Okay, so how long did you stay there?
I stayed a year.
And then you came back to the States?
Yes, that’s right.
Were you married at the time?
When did you get married?
I was married in Berea.
Oh, so while you were an undergraduate?
Did you have children at this time?
Our first child was born after I got my Ph.D. at Michigan State.
So the child was born in Michigan between the time you got your Ph.D. and the time you went to Europe?
So you went to Europe with a one-year-old?
No, she was eight months old.
Even worse — more difficult to travel.
Actually, she was a good traveler, and I learned that she was also a good contact with grandmothers who would teach me German.
So after the year, then you came back to the United States. Where did you go to when you came back?
I came back to Michigan State. I was at Michigan State for two additional years after.
And you were still working with Hiedemann?
And you continued your work on measurements of velocities in fluids?
And development of non-linear acoustics.
And after that two-year period, what was your next job?
I went to University of Tennessee.
You must have been there a long time, then, because if I add it up right, that’s about four years out of graduate school, so you probably were what, 28, 29 years old?
Probably — 28, probably. And I went as associate professor.
That certainly led to a very long and distinguished career there. It’s hard to ask about your career at Tennessee, since it spans such a long period of time. I’ll probably come back and circle that several times. But during the time there, what do you think was your greatest achievement?
Probably the greatest achievement was in development of nonlinear acoustics in solids.
And I first knew you from some graduate students that you trained in nonlinear acoustics in solids, but how many graduate students did you have while you were there?
Half Ph.D., half master’s.
That’s quite a number. How many of those do you still keep track of?
All of them.
I try to.
Are they all still alive?
Some of my graduate students have retired, and it’s very sobering to learn that your graduate students are retired.
I’ve learned recently of the death of one of my Ph.D. students, so I’ve reached that level where my Ph.D. students are beginning to depart, so it’s pretty sobering also. In fact, my first Ph.D. student died.
As a matter of fact, one of my Ph.D. students will join me. He has an apartment in Paris, but he’ll join me in Madrid.
While you were at the University of Tennessee, do you have any idea how many articles you published in scientific journals?
150, probably — more than 150.
How about books and things like that? Did you publish books?
Yes, I published one book.
What was the title of the book?
It was the proceedings of a conference that Oswald LeRoy and I had in Belgium.
So you edited the proceedings?
Let’s circle back around and come to the time you left the University of Tennessee and came to the University of Mississippi. That was how long ago?
So you’re approaching 20 years.
And since you’ve been at the University of Mississippi, what do you consider to be your greatest achievement?
Probably the graduate students that I have had at Ole’ Miss.
How many have you had?
I’ve had four or five. One of the graduate students came with me from UT, and he did his research here but went back to UT for his degree.
Are there other things in that era as far as career activities that you thought should be mentioned and could be considered important? I know for example, during that period of time, you were associate editor of the journal for many years. Are there any particular stories or things that stick out in your mind while you were doing that?
Well, editorial work is work.
Yes, it is. And it’s a lot of work. I know that also during that period of time, you were a traveling lecturer for something for the IEEE. What was that?
I was made distinguished lecturer for IEEE for one year, and I gave lectures in China and in Europe as well as in the United States.
What years was that?
Probably 1986 or ’87.
And when did you receive the silver medal in acoustics?
1988, I think. I think it was 1988.
We’ll come back to some of this, perhaps, in just a few minutes. But the next topic they’ve asked me to cover is to talk something about your family. I know that you are married now. You want to put your wife’s name?
My wife’s name is Mary Louise, but she has several names after that.
I know that you were married many, many years to your former wife. What was her name?
I know Joanne moved here with you from Tennessee, and unfortunately died not too long after that. What is your wife’s occupation?
My wife is retired. She was Louise Scott, and she had a business. Scott’s Forge was her business.
What was Scott’s Forge?
It was a framing shop, and she sold black powder for her husband.
Where was this?
It was actually in a building that has burned. It was in the old building that housed Scott’s Forge and a number of other businesses.
Here in Oxford?
In Oxford, yes.
I think the building was called The Warehouse.
Yes. (It was constructed as a Cotton gin.)
When did you meet your wife?
I met my wife soon after my first wife died.
Actually, I thought your first wife and your current wife actually knew each other.
Actually, they did.
They were friends, or just knew each other?
They just knew each other. They were members of the same fraternity or sorority.
Okay. So how did you meet your current wife?
My current wife I met in the choir.
And where did you meet your first wife?
I met my first wife at Berea.
In the choir.
We were in the choir together, yes.
So you’ve been married twice?
When did you marry your first wife? You said in Berea. That would have been about when?
And then your second wife, you married her…
How about your children? You have how many children?
I have three children. My daughter was eight months old when we went to Germany, and she is in Knoxville, and she’s a librarian in Knoxville.
Does she have children?
She has one son who has a library in Roanoke Virginia. And my oldest son has a business in Corinth, Mississippi. It’s a steel business. They manufacture steel for sale throughout the world.
What’s his name?
And does David have children?
David has two sons. One of them has a degree from the University of Tennessee, and the second one is in college at the moment. He’s a pilot. He already has his pilot’s license.
And the third child?
The third child is William, who is associate curator at a museum in California in Sacramento.
Does he have children?
I guess that means that you have three grandchildren?
I have three grandsons, no granddaughters.
How old are they?
The oldest grandson has a degree from UT, so he’s probably 23, and the youngest grandson is still in college.
Today’s date is 9 August ’07, and we are at the National Center for Physical Acoustics at the University of Mississippi in the State of Mississippi, and the country is United States. The time is about 1500, and I am in the process of interviewing Mack Breazeale for the Acoustical Society of America Technical Committee on Physical Acoustics, and this is tape number two. Okay, Mack, we’re back. We were talking about your children when we sort of went away, and I guess the question that we see here is, is there anything special about any of your children? I can’t imagine there not being, but if there’s anything in particular you would like to mention about any of your children, this is a good time to do it.
Probably, my daughter is special because it was through her that I learned German. It was not that she taught me German, but she was a good intermediary with grandmothers who enjoyed talking with her in German, and I could listen.
Does she now speak German?
No, no. I speak more German than she does.
I guess children learn it fast, but it maybe doesn’t stick around so long.
They forget it fast, too.
When Hans Bauer’s children were here, they picked up English immediately. They took a driving trip to Mexico, and within a few days, the children were speaking Spanish. Hans could only speak German. Let’s go into the next category. The next category has to do with some of your personal interests. What is your favorite form of entertainment?
Any particular type of music you enjoy?
Probably baroque music.
For many, many years, you were in Tennessee and the University of Tennessee. Did you not pick up a taste for country music during that time?
Nope. My son-in-law did. He makes banjos.
Oh, great. That part of the country is really famous for their famous banjo players, and a lot of people have them.
He usually would win the country music banjo-picking contest.
The next question is asking you to name some of your favorite authors of books.
Probably the most recent book was Nobel Prize. It was written recently.
Do you remember the author?
No, I don’t.
I remember what the book was about, but I don't remember the author, either. How about movie stars?
I don’t enjoy movies.
I don’t, either. I agree with you. How about music? Singers or songs that you particularly like?
Classical music, I guess, is my favorite.
Do you like opera?
I can live with it.
Or without it?
How about television?
Television, well, news programs are interesting for me. And public broadcasting. Some of the specials public broadcasting are very nice.
How about special sports activities? Do you like football or baseball or basketball?
Well, actually, I saw one football game at UT. I took my father, but that’s the only football game. Since I’ve come to Ole’ Miss, I’ve learned to watch football.
Well, it’s religion here more than it is sports, so we’ll put that in a different category.
And my wife is interested in it.
Does she enjoy more than football?
Yes, we all enjoy basketball, too.
How about the women’s team in Tennessee?
My sister was a basketball player, but I wasn’t.
How about a particular artist or art type that you enjoy?
Well, I’ll leave it to my son to enjoy the art.
He tells you what’s good?
That’s good. Is there a particular quote that you carry around with you that you like to pass on to others?
Well, I wrote down a quotation: “Scientific progress ultimately depends upon absolute integrity and honesty. A scientist therefore must pursue truth in such a manner that the path between himself and his goal can never be totally obstructed by any other human being.”
And who do you attribute it to, yourself?
I wrote it.
What are your hobbies today? Do you have hobbies?
Hunting and fishing, probably.
You like to travel, too, don’t you?
I do, but travel involves making sure that all of the passengers are not armed and such things. It’s a little bit time-consuming — not as much fun.
But you are still planning on going to Madrid?
Yes, I’m planning on going to Madrid for the international conference on acoustics.
That would be an interesting trip. I think Madrid is relatively safe, although they had the subway explosion.
Well, I was in Madrid 30 years ago, and my wife broke her arm in Madrid.
Is that right? By a fall?
What are your future plans? Other than going to Madrid, what do you have planned for the next few years?
For the next few years, probably do some research.
On what topic?
With what particular problem do you want to address?
Non-linear acoustics. And one aspect of non-linear acoustics that’s interesting to me is parametric acoustics — acoustical parametric oscillation. This is a subject that I’ve been interested in for a number of years. Probably, my first publication was in 1970 or something like that on parametric oscillations. I’ve investigated parametric oscillation, and I found out that acoustical parametric oscillation at least dates from 1958.
Are you going to look at specific non-linear materials that you have in mind to study the parametric oscillation?
Well, actually, the phenomenon is very interesting. It’s essentially a resonance phenomenon, and there are special conditions under which parametric oscillation exists.
Parametric oscillation depends on some property or some nature of the non-linear constant, doesn’t it?
Actually, parametric oscillation depends on — well, it’s a resonance phenomenon, and probably the parametric oscillation is interesting, because at one driver’s frequency, the response is half that frequency. So it’s a rather interesting phenomenon.
Let’s talk about some of the research that you’ve done in the past, and I’ll key on certain things that I’m familiar with, although you might have the things that you would like to put in that perhaps are of more interest to you. When I first became familiar with your work, it was because of the nonlinear properties of solids that you were studying using ultrasonic techniques. What was the primary outcome of that, do you think?
I learned that all solids are nonlinear. And of course, we measured the nonlinearity parameters on a number of solids.
Weren’t you able to relate some of the nonlinear parameters, the harmonic properties, to structures of the crystal — properties of the crystal itself?
All crystals are nonlinear, and we studied the nonlinear properties of cubic crystals, primarily.
And nonlinearity comes from Van Der Wahl’s forces or whatever that holds the crystal together?
That’s right. Actually, the nonlinearity is obvious when one realizes that a linear crystal requires a parabolic force, and the force between atoms is not parabolic, and so parabolic approximation is Hook’s law, and Hook’s law has been around a long time, but it is an approximation. And we’re going beyond that approximation.
A very small amplitude approximation.
Actually, I investigated that and found that even at zero amplitude, the crystal is nonlinear.
I guess you never can get all the way at the bottom of that well, can you?
When you get to the bottom of the well, you’ll find that the bottom of the well is not a parabola.
These are some of the things that I remember about the large body of your research. Are there any things that you’ve learned like from other research topics?
Well, I’ve done a lot of investigation of such things as Bragg diffraction of light by ultrasound. Bragg diffraction is a very interesting phenomenon. Of course, the diffraction of X-rays is necessary to determine the spacing of atoms in a crystal. But Bragg diffraction of X-rays is a phenomenon that doesn’t allow imaging, Bragg diffraction of light by ultrasound allows one to do imaging of the ultrasonic wave front, and that has always been a fascination for me, because it’s a phenomenon that is unique to Bragg diffraction of light by ultrasound.
I’ve noticed that you’ve also done a fair amount of Schlieren work. What was the motivation for that?
That’s a good one!
But Schlieren imaging is a good way to determine the acoustical properties of a solid or a reflector. Actually, the reflection phenomenon was the reason for investigating Schlieren. We were able to reflect sound from a solid-liquid interface, and then we realized that the incident sound wave on the interface produces a surface wave, and the propagation of the surface wave is very interesting, because the energy goes from the liquid into the surface wave, and then is reflected back into the liquid. So there is a displacement of the reflected beam. That displacement is the result of the interaction of the surface wave with the incident wave. And we have been playing with that, because if the surface has a periodicity, then the periodicity can change the phase of the wave, and the result is that a 180-degree change of the phase means that the velocity goes backwards rather than forward. And so the incident beam can excite a backward-directed surface wave, and then this backward-directed surface wave can excite a beam in the liquid. And the result is that if there is a periodicity, and if the angle is proper, then the surface wave can propagate in the backward direction. And so this is an interesting phenomenon that probably has been observed in the Roman auditoria, and the periodicity comes from the fact that the seats are at a specific distance from each other, and I think that that can be the reason that some of the Roman auditoria are so good, because of this backward-directed surface wave.
I know that we talked earlier about you liking travel. Where have you enjoyed traveling most?
Yes. One time I was in Hawaii, and I read in the newspaper that there had been an earthquake in Japan. Fortunately, I had left Japan just the day before the earthquake.
So it made you appreciate Hawaii more.
Well it sure is a beautiful place. I think this covers the questions I wanted to ask. I think after you have a chance to think about this, you might want to add something. And if other things come to mind that you would like to have in this, in the next couple of days we can add that. Other than that, I think we’ve covered all the things that we have on the list. This is the closing of the oral history interview with Mack Breazeale. It is now 15:15. We are at the University of Mississippi. I am closing at this point.