Sound Velocity Estimation Research Articles

Pulse centroid echo method and apparatus for enhanced sound velocity estimation in vivo

A method and apparatus of enhancing the accuracy of in vivo sound velocity estimation by identifying segments of different sound velocity along a tracked ultrasound beam. The effects of refraction on the tracked beam at the interface between tissue regions are estimated. Also disclosed is a technique for estimating the refractive effects of naturally occurring and artificially introduced acoustical contrast fluids. The accuracy of the sound velocity measurements is increased by utilizing the centroid-to-centroid distance between the pulses produced by ultrasound sending and receiving transducers in calculating the ultrasound beam velocity.

Pulse echo method and apparatus for sound velocity estimation in vivo

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Method for enhancing the accuracy of in vivo sound velocity estimation

A method of enhancing the accuracy of in vivo sound velocity estimation by identifying segments of different sound velocity along a tracked ultrasound beam. The effects of refraction on the tracked beam at the interface between tissue regions are estimated. Also disclosed is a technique for estimating the refractive effects of naturally occurring and artificially introduced acoustical contrast fluids.

4777958 Method for enhancing the accuracy of in vivo sound velocity estimation

4777958 Method for enhancing the accuracy of in vivo sound velocity estimation

Two-sensor methods for the measurement of sound intensity and acoustic properties in ducts

A unified theoretical approach to the development of two-sensor methods is presented. It is shown that various methods developed in the last 10 years for sound intensity measurement and for the measurement of acoustic properties in ducts may be systematically derived from a general decomposition theory. In the decomposition theory, the incident and reflected wave auto and cross spectra are obtained from a set of decomposition equations using the measurement of the total acoustic pressure at two arbitrary points in a one-dimensional steady, random sound field. The application of the wave spectra to the measurement of sound intensity and acoustic properties follows directly. It is further shown that the decomposition theory predicts a set of characteristic wavenumbers at which two-sensor methods fail to yield meaningful data. Experimental data are presented showing the application of the decomposition theory to acoustic property determination, sound intensity measurement, and the estimation of sound pressure and particle velocity in a duct.

Estimation of Sound Velocity, Tensile Strength and Damping Capacity of Cast Iron with Effective Area Fraction Model

Estimation of Sound Velocity, Tensile Strength and Damping Capacity of Cast Iron with Effective Area Fraction Model

An In Vivo Technique for Estimation of Size and Relative Sound Velocity of Breast Tumor using Distorted Image in Ultrasonic Tomogram

A technique is proposed for estimation of size and sound velocity of a massive tissue relative to its surroundings that is larger with ultrasonic beam width. This technique is based on a distorted image of a plane reflector behind a massive tissue in an ultrasonic tomogram, which is caused by ultrasonic refraction. An example of a breast tumor with an obscure boundary is shown to demonstrate the usefulness of this technique.

Estimation of sound-velocity by the method of coincidences

The isolated perfused mammalian heart preparation was established in 1897 by Oscar Langendorff. The method was developed on the basis of the isolated perfused frog heart established by Elias Cyon at the Carl Ludwig Institute of Physiology in Leipzig, Germany in 1866. Observations made using both methods at the end of the 19th and at the beginning of the 20th century led to important discoveries, forming the basis for our understanding of heart physiology. This included the role of temperature, oxygen and calcium ions for heart contractile function, the origin of cardiac electrical activity in the atrium, the negative chronotropic effect of vagus stimulation and the chemical transmission of impulses in the vagus nerve by acetylcholine. Langendorff himself demonstrated that the heart receives its nutrients and oxygen from blood via the coronary arteries and that cardiac mechanical function is reflected by changes in the coronary circulation.The method underwent many modifications but its general principle remains the same today. Blood, or more commonly crystalloid perfusates, are delivered into the heart through a cannula inserted in the ascending aorta, either at constant pressure or constant flow. Retrograde flow in the aorta closes the leaflets of the aortic valve and as a consequence, the entire perfusate enters the coronary arteries via the ostia at the aortic root. After passing through the coronary circulation the perfusate drains into the right atrium via the coronary sinus.The simplicity of the isolated mammalian heart preparation, the broad spectrum of measurements which can be done using this method, its high reproducibility and relatively low cost make it a very useful tool in modern cardiovascular and pharmacological research, in spite of a few shortcomings. In the last decade the method has brought many important advances in many areas including ischemia–reperfusion injury, cell-based therapy and donor heart preservation for transplant.