DESCRIPTION

The primary goal of Basic Research is to increase scientific understanding.   Although increased understanding is the main objective, there is often a large benefit to society from using the understanding from basic research to solve practical problems.   As an example, Charles H. Townes was awarded the Nobel Prize in Physics in 1964 for fundamental research that led to the laser, a device that is now common in areas as diverse as space probes, medicine, and supermarkets.   Thus, basic research is important because it provides farsighted, high-payoff research, including the critical enabling technologies necessary for technological progress.

DIRECTORY

RESEARCH PROGRAMS

NCPA has active basic research programs in Atmospheric Acoustics, Materials Science, and Thermoacoustics. Each program has contributed to a better understanding of the fundamental science and to a solution of practical problems.

Research in Atmospheric Acoustics involves experimental and theoretical study of the propagation of audible sound in the atmosphere as well as “infrasound” sound below audible range), which can travel thousands of miles.

Figure Caption:  Upward-refracting daytime atmosphere with turbulence.

The research in Materials Science uses “ultrasound” (sound above audible range) to study the fundamental, physical properties of exotic manmade materials such as metallic glasses, ceramics, and biomaterials and to perform non-destructive testing of materials. In addition to giving valuable information on how a material responds to stress, a thermal profile of physical properties can illuminate subtle phase transitions that other measurements cannot detect.

Figure Caption:  A skutterudite sample mounted between transducers.

The Thermoacoustics program studies the transfer of heat in acoustic processes. Such research has let to thermoacoustic refrigerators, gas liquefiers, and engines that run off waste heat.

Figure Caption:  A stack filled with a porous ceramic disk.

MAJOR ACCOMPLISHMENTS

The Atmospheric Acoustics research program has been recognized worldwide for over 20 years.   Because of its recognized leadership in atmospheric acoustics, in 2002 NCPA became a core institution in the U.S. Army Acoustics Center of Excellence, with the mission to carry out basic research in outdoor sound propagation.   In 1998, NPCA was asked by the Department of Defense to supervise the installation of U.S. infrasound stations as part of the global nuclear monitoring function.

The Material Science research program is a new research effort at NCPA.   A state-of-the-art laboratory for resonant ultrasound spectroscopy (RUS) was established in 1999.   The laboratory is unique in that it can use RUS to measure the physical properties of samples at temperatures exceeding 1000 K.

NCPA has been involved in Thermoacoustic studies since 1991.   Fundamental theoretical and experimental studies have been carried out on thermoacoustic refrigeration and thermoacoustic engines.   Recently, a method for using inert gas condensation in thermoacoustic refrigeration was patented.

FUTURE GOALS

As a core institution in the U.S. Army Acoustic Center of Excellence, NCPA will be provide cutting-edge scientific knowledge and technology to Army acoustic laboratories responsible for the design and fielding of future military acoustics systems.   The scientific potential of the worldwide network of 60 infrasound listening stations has just begun to be tapped.   NPCA will serve as the focal point for scientific uses of the global infrasound monitoring system.

The Materials Science program is just beginning, but has a very bright future due to the growing use of new manmade classes of materials.   Studies using acoustic methods, such as RUS, will provide the experimental guidance needed to understand existing materials and to design new materials with desired physical, chemical, and electronic properties.

The future focus of the Thermoacoustics program will be the development of experimental and theoretical models to optimize power generation in small thermoacoustic devices.   The work will be carried out in collaboration with the University of Utah.