Note on the prong configuration of an x-array hot-wire probe.
The x-array hot-wire probe with prongs perpendicular to the mean flow is found to be unacceptable for turbulence measurements.
LOW-COST WIND TUNNEL FOR AEROSOL INHALATION STUDIES
A low-cost wind tunnel for aerosol studies has been designed, constructed, and evaluated for aerosol uniformity with 2- and 0.46-micron particles. A commercial nebulizer was used to produce the suspended test particles, and a custom-made, four-hole injector was used to introduce the aerosol into the wind tunnel. A commercially available optical par...
Application of optical coherence interferometry to measure the spatial profile of fluid flow velocity
The spatial profile of fluid flow velocity in transparent glass conduits is measured using optical Doppler tomography (ODT). The flow velocity at any spatial location in the conduits is determined by measuring the Doppler shift of backscattered light from moving microspheres in the fluid. ODT is an accurate and inexpensive method for high resolutio...
Variability of a three-layered appearance in intravascular ultrasound coronary images: a comparison of morphometric meas...
The purpose of the study was to compare four intravascular ultrasound (IVUS) machines in vitro for their image representation of coronary arterial walls. There has been considerable variability among reported studies on the accuracy of morphometric measurements of coronary arteries by IVUS. This variability may be caused in part by the difference i...
Variability in tissue characterization of atherosclerotic plaque by intravascular ultrasound: a comparison of four intra...
Different intravascular ultrasound (IVUS) systems vary in their image presentation. The purpose of this study was to compare four IVUS systems in vitro to determine the accuracy of tissue characterization of atherosclerotic plaque compared with histology. Ninety-eight plaque segments from 23 formalin-fixed human iliac arteries were imaged in saline...
Optical Doppler tomographic imaging of fluid flow velocity in highly scattering media.
An optical Doppler tomography (ODT) system that permits imaging of fluid flow velocity in highly scattering media is described. ODT combines Doppler velocimetry with the high spatial resolution of low-coherence optical interferometry to measure fluid flow velocity at discrete spatial locations. Tomographic imaging of particle flow velocity within a...
Measurement of fluid-flow-velocity profile in turbid media by the use of optical Doppler tomography.
Optical Doppler tomography is demonstrated to be a simple, accurate, and noncontact method for measuring the fluid velocity of laminar flow in small-diameter (~0.5-mm) ducts. Studies are described that utilize circular (square) plastic (glass) ducts infused with a moving suspension of polymer microspheres in air and buried in an optically turbid me...
First experience with imaging core wires.
This study is the first assessment of feasibility and clinical usefulness of an imaging wire. The device used is a 0.018" flexible cable mounting a 30 MHz piezoelectric crystal at the end. The only possible application of the wire in its current configuration is the assessment of balloon expansion with over-the-wire balloon catheters. In this study...
Noninvasive imaging of in vivo blood flow velocity using optical Doppler tomography.
We report the development of an optical technique for noninvasive imaging of in vivo blood flow dynamics and tissue structures with high spatial resolution (2-10 microm) in biological systems. The technique is based on optical Doppler tomography (ODT), which combines Doppler velocimetry with optical coherence tomography to measure blood flow veloci...
A comparative study of human skin thermal response to sapphire contact and cryogen spray cooling
Surface cooling, in conjunction with various thermally mediated therapeutic procedures, can provide a means to protect superficial tissues from injury while achieving destruction of deeper targeted structures. We have investigated the thermal response of in-vivo human skin to: 1) contact cooling with a sapphire window (6-12 degrees C); and 2) spray...
