Technical Challenge: The US government needed a noninvasive sensor to identify chemical warfare compounds and highly toxic chemicals inside sealed containers accurately and rapidly.
Solution: We developed the Acoustic Resonance Spectroscopy (ARS) and the Swept Frequency Acoustic Interferometry (SFAI) technique to noninvasively identify such chemicals accurately and in matter of seconds. The SFAI technique allowed determination of multiple physical properties of any fluid with a single measurement with very high accuracy.
Technical Challenge: The Chevron Corporation needed a sensor system to determine composition and flow of multiphase (oil/water/gas) hydrocarbons from oil/gas wells continuously and accurately. The existing instruments were either too expensive or had many limitations that did not fulfil the requirements.
Solution: The SFAI technique developed earlier for noninvasive identification of chemical weapons was a good starting point but required extensive modifications and enhancements to be applicable in the case of flowing multiphase fluids. The measurement also needed to be speeded up by four orders of magnitude. We developed a frequency-chirp technique that provided both real-time composition and flow measurement; this has been developed and extensively tested and validated in the field prior to commercialization.
Technical challenge: The US government needed a way to enhance the sensitivity of existing instruments to identify air-borne particulate matter. It needed to be simple, low maintenance, and used low power.
Solution: We developed an acoustic concentration approach with no moving parts that used the radiation force of sound to concentrate air-borne particulate matter in a continuous manner. This approach opened up a host of new possibilities and led to a large number of applications from acoustic flow cytometer for biological cell identification (commercial product by Life Sciences) to acoustic oil-water separation to acoustically engineered materials.
Technical challenge: The Chevron Corporation needed a way to the image the environment outside a borehole to monitor borehole integrity and other features.
Solution: The team used nonlinear acoustics and Fluorinert to create a collimated acoustic source with a frequency range 10-120 kHz and used this for imaging purposes. This frequency range provided some unique possibilities that were not realizable with either existing low frequency seismic sources or very high frequency (~ 1 MHz) sources. This frequency range provided the required depth penetration of several feet and spatial resolution of ~ 1 mm. In addition, several other types of collimated sources were developed that used acoustic metamaterials and a novel linear (axial) array source for use in boreholes.
This technique was also adapted for Chevron to develop a 3D acoustic imaging system to image objects submerged in optically opaque and acoustically highly attenuating fluids, such as drilling mud. There are many other uses of this imaging technique in other areas of technology including biomedical.
We employ postdoctoral fellows who are experimentalists with background in applied physics, signal processing, acoustics, wave propagation, nondestructive testing, materials and sensors. Our team is part of the Materials and Applications Division at LANL that has extensive capabilities in the areas of materials science and nanotechnology.
Contact: Dr. Dipen N. Sinha, Laboratory Fellow
Address: MPA-11, D429, Los Alamos National Laboratory, Los Alamos, NM 87545