Velocity Measurement
Velocity Measurement - Related Videos
08:41
Ultrasound Velocity Measurement in a Liquid Metal Electrode
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Cited by 14 •
2015
Ultrasound velocimetry is used to study mixing by fluid flow in liquid metal electrodes. The focus of this manuscript is to illustrate the methods used for making precise, spatially-resolved ultrasound measurements while limiting oxidation and controlling and monitoring temperature, applied current, and the heater power being supplied.
10:56
Automated Measurement of Microcirculatory Blood Flow Velocity in Pulmonary Metastases of Rats
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Cited by 2 •
2014
A method is presented to measure microcirculatory blood flow velocity in pulmonary cancer metastases of the pleural surface in rats in an automated fashion, using closed-chest pulmonary intravital microscopy. This model has potential to be used as a widespread tool to perform physiologic research on pulmonary metastases in rodents.
07:53
Micro-particle Image Velocimetry for Velocity Profile Measurements of Micro Blood Flows
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Cited by 12 •
2013
Micro-particle image velocimetry (μPIV) is used to visualize paired images of micro particles seeded in blood flows which are cross-correlated to give an accurate velocity profile. Shear rate, maximum velocity, velocity profile shape, and flow rate, each of which has clinical applications, can be derived from these measurements.
07:32
Phagosome Migration and Velocity Measured in Live Primary Human Macrophages Infected with HIV-1
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Cited by 4 •
2016
We describe a method to measure the velocity of phagosomes moving towards the cell center in living cells infected with or without the human immunodeficiency virus (HIV) type 1, using spinning disk confocal fluorescence microscopy to identify fluorescent infected cells and bright field microscopy to detect phagosomes.
10:28
Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids
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Cited by 15 •
2014
This paper demonstrates the experimental procedure to measure terminal settling velocities of spherical particles in surfactant-based shear thinning viscoelastic fluids. Fluids over a wide range of rheological properties are prepared and settling velocities are measured for a range of particle sizes in unbounded fluids and fluids between parallel walls.
FAQs
Doppler ultrasound estimates blood-flow velocity from changes in reflected sound waves. Moving blood cells alter the frequency of the returning signal, and that shift provides information about how quickly blood is moving relative to the measurement system. The result connects a measurable signal change with circulation through vessels and helps characterize cardiovascular motion.
Velocity measurement includes direction, not only the rate of motion. In medical imaging, reflected signals can contain frequency or phase changes associated with moving structures. Interpreting these changes helps distinguish the direction of blood or fluid movement, which adds physiological meaning beyond a single speed value and supports assessment of motion within vessels and the heart.
Tracking displacement over time determines motion by comparing position changes across a time interval. Signal-based methods instead infer motion from changes in reflected frequency or phase. Both approaches quantify velocity, but they rely on different observable features of motion. This distinction explains why medical systems can assess movement either through positional information or through signal behavior.
A Doppler ultrasound examination detects sound waves reflected from moving blood cells and evaluates the resulting frequency shifts. Those shifts are used to infer blood-flow velocity, including its directional component. The measurement therefore proceeds from signal reflection to shift detection and then to a quantitative description of circulation, making the technique relevant to vascular and cardiac assessment.
Phase-contrast MRI uses changes in the phase of imaging signals to map fluid motion. Applied to vessels and the heart, this approach produces information about how fluid moves through those structures rather than relying only on anatomical appearance. The resulting velocity information can support evaluation of circulation and cardiac function within a broader medical imaging study.
Velocity measurements help relate physical motion to clinically relevant physiology. In medicine, they can support assessment of circulation, cardiac function, vascular disease, and response to treatment. Doppler ultrasound is suited to blood-flow evaluation through reflected sound-wave shifts, while phase-contrast MRI can map fluid motion across vessels and the heart, allowing investigators to study complementary aspects of cardiovascular function.