University Events

Description: Part of the Joint UMass Dartmouth – Naval Undersea Warfare Center (NUWC) Seminar Series

Speakers: Mr. Thomas R. Howarth and Mr. Christian R. Schumacher
Naval Sea Systems Command, Division Newport, Newport, RI

Location: Liberal Arts Building Room 117
Abstract:

Traditional acoustic transduction sources typically begin with the generation of an electrical excitation pulsed through an amplifier into an electroacoustic material (such as a piezoelectric ceramic or piezocomposite or a magnetostrictive ferromagnetic compound) to create a mechanical vibration. This vibration is then converted into an acoustic wave to produce sound. The lower the preferred transmitting frequency (and hence, longer acoustic detection range) desired, the larger the size of conventional transducer is required. Often this means that for acoustic projectors producing sound at frequencies below a few kHz, that the electroacoustic device will need to be very large in order to produce very long sound waves. This has a limitation for incorporating low frequency, long range detection sonars on smaller autonomous underwater vehicles (AUVs).

The topic of our presentation is an acoustic source technology that relies on the conversion of thermal energy into acoustic energy. Though this principle of thermal acoustics is not new, it is the advent of carbon nanotube (CNT) materials that offers a potential means to provide low frequency sound in thin transduction packages. The discussions will begin with an overview of thermal acoustics and then introduce these initial U.S. Navy studies for incorporating the CNTs into a useable transduction device. These discussions will include a detailing of our recent and on-going efforts for the encapsulation and packaging.

Biographies:

Dr. Thomas R. Howarth is involved in the research, development, testing and evaluation (RDT&E) of acoustic transduction technologies with an emphasis on implementing recent laboratory materials into prototyping devices for U.S. Navy applications. In particular, he is a chief architect for developing piezocomposite materials and cymbal flextensionals into SONAR devices for acoustical applications. More recently Howarth has been conducting research with acoustical metamaterials and carbon nanotube transducers. Since 2000 he has been stationed at the Naval Sea Systems Command Division Newport in Newport, RI where he holds the Distinguished Chair for Transduction and Acoustic Sensors.

Christian R. Schumacher graduated from Boston University with a BS in Mechanical Engineering and a MS in the area of Engineering Materials Science. His research at BU focused on applied materials processing, primarily focused on Solid State energy conversion devices, funding was provided by the Department of Energy (DOE). Christian started working for the Department of the Navy (DON), initially in two year Navy wide rotation program (NCWPD), during which he gained research experience working with NAVSEA, NRL, SPAWAR, and shipyard experience working on both surface ships and submarines. At the completion of the program, Christian accepted a full time position at NUWC in Code 8535: Energy and Propulsion Branch.

Faculty, staff and students are encouraged to attend.
Refreshments will be served.

More information: Dr. Ramprasad Balasubramanian, 508.910.6919 or r.bala@umassd.edu.