Sonoluminescent tomography

A novel optical imaging technique called sonoluminescent tomography (SLT) was developed for cross-sectional imaging of strongly scattering media noninvasively. Sonoluminescence, which was generated internally in the medium by continuous-wave ultrasound, was used to produce a two-dimensional image of an object embedded in a scattering medium by raster scanning the medium. The image had a high contrast and good spatial resolution. The spatial resolution was limited by the focal spot size of the ultrasound and can be improved by tightening the focus. This inexpensive imaging technique has potential applications in medicine and other fields related to scattering media

Two-dimensional imaging of dense tissue-simulating turbid media by use of sonoluminescence

An optical imaging technique that is believed to be novel was developed for noninvasive cross-sectional imaging of tissuelike turbid media. By use of a sonoluminescence signal generated internally in the media with a 1-MHz continuous-wave ultrasound, two-dimensional images were produced for objects embedded in turbid media by a raster scan of the media. Multiple objects of different shapes were resolved with this imaging technique. The images showed a high contrast and good spatial resolution. The spatial resolution was limited by the focal size of the ultrasonic focus

Sonoluminescent tomography of strongly scattering media

A novel optical imaging technique called sonoluminescent tomography was developed for cross-sectional imaging of strongly scattering media noninvasively. Sonoluminescence, which was generated internally in the medium by cw ultrasound, was used to produce a two-dimensional image of an object embedded in a scattering medium by means of raster scanning the medium. The image had a high contrast and good spatial resolution. The spatial resolution was limited by the focal-spot size of the ultrasound, and one could improve the resolution by tightening the focus. This inexpensive imaging technique has potential applications in medicine and other fields related to scattering media

Deep subwavelength optical imaging using correlated nano-torches

The authors propose and numerically demonstrate an ultra-high resolution (wavelength/50∼40 nm at wavelength λ=2.08 μm, high-throughput (∼66%), and non-destructive optical lens with a large contrast-to-noise ratio, based on the notion of correlated nano-torches formed in a subwavelength metallic grating. The correlations between the torches also allow the determination of the complex refractive index of the sample

Sonoluminescence tomography of turbid media

A novel optical imaging technique was developed for noninvasive cross-sectional imaging of tissue-like turbid media. By use of a sonoluminescence signal generated internally in the media by continuous-wave ultrasound, two-dimensional images were produced for objects embedded in turbid media by raster scanning the media. Multiple objects of different shapes were resolved using this imaging technique. The images showed a high contrast and good spatial resolution. The spatial resolution was limited by the focal size of the ultrasonic focus

Strength of bolted ring-type connections of solid round leg members of guyed communication towers.

The objective of the investigation is to study the strength of bolted ring-type connections used for solid-round leg members of all-welded steel towers subjected to tensile loads and to determine whether the current practice of ignoring the eccentricity of the connection can be justified or not. The load carrying capacity and maximum gap were determined experimentally and by finite element analysis. A total of eighteen specimens divided into three groups were tested. Group 1 consisted of six specimens of 25.4 mm (1.0 in.) leg size and 22.2 mm (7/8 in.) bolt size with no girls, group 2 consisted of six specimens of 38.1 mm (1.5 in.) leg size and 22.2 mm (7/8 in.) bolt size with girts, while group 3 consisted of six specimens of 50.8 mm (2.0 in.) leg size and 31.8 mm (1-1/4 in.) bolt size with girts. All the specimens were subjected to tension loading. The investigation focused on: load-gap relationship under tension loading and the tensile capacity of the connections. In the finite element analysis, three-dimensional finite element models were developed with the ABAQUS package in order to simulate the strength and gap behavior of the bolted ring connections. It was found that the results from the finite element models agreed closely with the experimental values and that the strength of the connection increased with increase in leg size (for the same size bolt). The results from both the finite element analysis and the experiments show that the failure loads are less than the axial load capacities according to Canadian Standard for all groups. Comparing experimental failure loads to the axial load capacities according to AISC-LRFD, they are less for Groups 1 and 3 and are almost the same for Group 2.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2002 .S54. Source: Masters Abstracts International, Volume: 42-03, page: 1001. Adviser: K. S. Madugula. Thesis (M.A.Sc.)--University of Windsor (Canada), 2003

Sound and light in turbid media

Two imaging techniques combining ultrasound and light are reviewed. The motivation is to combine the advantages of optical information and acoustic imaging resolution. The first technique is sonoluminescence tomography, where a sonoluminescence signal generated internally in the media by continuous-wave ultrasound is used. Two-dimensional images can be produced for objects embedded in turbid media by raster scanning the media. The second technique is ultrasound- modulated optical tomography, where a frequency-swept ultrasonic wave was used to modulate the laser light passing through a scattering medium. Multiple 1D images obtained at various positions perpendicular to the ultrasonic axis were composed to obtain a 2D tomographic image of the medium

Combining sound and light in scattering media

Two imaging techniques combining ultrasound and light are reviewed. The motivation is to combine the advantages of optical information and acoustic imaging resolution. The first technique is sonoluminescence tomography, where a sonoluminescence signal generated internally in the media by continuous-wave ultrasound is used. 2D images can be produced for objects embedded in turbid media by raster scanning the media. The second technique is ultrasound-modulated optical tomography, where a frequency-swept ultrasonic wave was used to modulate the laser light passing through a scattering medium. Multiple 1D images obtained at various positions perpendicular to the ultrasonic axis were composed to obtain a 2D tomographic image of the medium

Focusing light through scattering media by full-polarization digital optical phase conjugation

Digital optical phase conjugation (DOPC) is an emerging technique for focusing light through or within scattering media such as biological tissue. Since DOPC systems are based on time reversal, they benefit from collecting as much information about the scattered light as possible. However, existing DOPC techniques record and subsequently phase-conjugate the scattered light in only a single-polarization state, limited by the operating principle of spatial light modulators. Here, we develop the first, to the best of our knowledge, full-polarization DOPC system that records and phase-conjugates scattered light along two orthogonal polarizations. When focusing light through thick scattering media, such as 2 mm and 4 mm-thick chicken breast tissue, our full-polarization DOPC system on average doubles the focal peak-to-background ratio achieved by single-polarization DOPC systems and improves the phase-conjugation fidelity

Suppressing excitation effects in microwave induced thermoacoustic tomography by multi-view Hilbert transformation

Microwave induced thermoacoustic tomography (TAT) images usually suffer from distortions arising from the microwave polarization effect and standing wave effect. The microwave polarization effect, resulting from linearly polarized microwave illumination, splits the image of the object along the polarization direction, while the standing wave effect, when the object size is larger than the microwave wavelength within the object, modulates the image of the object. Both effects cause non-uniform energy distribution in a uniformly absorbing object and create artifacts in the reconstructed images. To address these problems in TAT, we propose an image reconstruction method that combines multi-view Hilbert transformation with the back-projection algorithm. We experimentally validate this method by imaging breast and brain tumor phantoms, showing that the aforementioned distortions are significantly suppressed. We anticipate that this method will contribute to clinical tumor diagnosis