The total-count technique: A new principle in flow measurement

Hull, D. E.

doi:10.1016/0020-708x(58)90020-6

Cited by 37 publications

(9 citation statements)

References 2 publications

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“…This was accomplished in [4] by modeling the detection process as a radioactive flow measurement [8], such as employed in high-performance radioactive liquid chromatography [9], by defining an effective residence time…”

Section: Radon Transport As a Process Of Macroscopic Diffusionmentioning

confidence: 99%

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Analysis of Residence Time in the Measurement of Radon Activity by Passive Diffusion in an Open Volume: A Micro-Statistical Approach

Silverman¹

2017

WJNST

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Residence time in a flow measurement of radioactivity is the time spent by a pre-determined quantity of radioactive sample in the flow cell. In a recent report of the measurement of indoor radon by passive diffusion in an open volume (i.e. no flow cell or control volume), the concept of residence time was generalized to apply to measurement conditions with random, rather than directed, flow. The generalization, leading to a quantity r t ∆ , involved use of a) a phenomenological alpha-particle range function to calculate the effective detection volume, and b) a phenomenological description of diffusion by Fick's law to determine the effective flow velocity. This paper examines the residence time in passive diffusion from the micro-statistical perspective of single-particle continuous Brownian motion. The statistical quantity "mean residence time" r T is derived from the Green's function for unbiased single-particle diffusion and is shown to be consistent with r t ∆ . The finite statistical lifetime of the randomly moving radioactive atom plays an essential part. For stable particles, r T is of infinite duration, whereas for an unstable particle (such as 222 Rn), with diffusivity D and decay rate λ , r T is approximately the effective size of the detection region divided by the characteristic diffusion velocity Dλ . Comparison of the mean residence time with the time of first passage (or exit time) in the theory of stochastic processes shows the conditions under which the two measures of time are equivalent and helps elucidate the connection between the phenomenological and statistical descriptions of radon diffusion.

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Section: Radon Transport As a Process Of Macroscopic Diffusionmentioning

confidence: 99%

“…Use of the preceding expressions (8) and (9) together with relations (4) and (5) leads to the following closed form expression for the residence time…”

Section: Radon Transport As a Process Of Macroscopic Diffusionmentioning

confidence: 99%

Analysis of Residence Time in the Measurement of Radon Activity by Passive Diffusion in an Open Volume: A Micro-Statistical Approach

Silverman¹

2017

WJNST

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“…The indicator dilution technique for discharge measurement existed as early as the turn of the twentieth century (Hamilton, 1953). The dilution technique did not require knowledge of the flow depth, width, or velocity and could be performed rapidly (Hull, 1958). Fegler (1953 introduced heat as an indicator using the dilution technique for determining cardiac output in mongrel dogs.…”

Section: Introductionmentioning

confidence: 99%

CHANNEL DISCHARGE MEASUREMENT BY THERMODILUTION¹

Wittier¹,

Abt²,

Sanders

1987

J American Water Resour Assoc

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An investigation was conducted to determine the feasibility of applying thermodilution technology to discharge measurements in small open channels. A series of tests were performed in which the time‐temperature dilution curves were recorded and analyzed. The independent variables included the channel discharge, the injectate drop height, the volume of tracer, and the mixing distance. Flows ranged from 0.67 cfs to 2.45 cfs with Froude numbers less than 0.30. The results indicated that the thermodilution technique is a feasible method for discharge measurement. It was determined that a heat content, 1°, of 40°C provides a design criteria in which the mixing distance was related to the flow depth and discharge in a rectangular channel. An empirical expression was derived to determine the approximate mixing distance as a function of the flow depth.

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“…Radioisotopes have been used in different manners for measurements of discharge and sediment movement [International Atomic Energy Agency, 1963Agency, , 1967Belikov et al, 1964;Schuster, 1965;Stout, 1967;Hull, 1958;Crickmore and Lean, 1962;Kidson and Cart, 1962;Hubbell and Sayre, 1964]. To the writers' knowledge no research has been published concerning tracing individual radioactive particles for flow velocity measurement.…”

Section: Introductionmentioning

confidence: 99%

Velocity Measurement with Radioactive Spheres

Yen¹,

McGillivray²

1970

Water Resources Research

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Experimental evidence shows that the use of radioactive spheres as a flow velocity tracer is feasible. The technique involves trapping a small amount of radioisotope inside a sphere and then measuring the motion of the sphere in the flow. For steady uniform subcritical turbulent flows tested with the Reynolds number up to 13,000 and the flow depth to sphere diameter ratio greater than 1.7 the accuracy of flow velocity measurement with floating tracers is usually within ± 7%. The accuracy can be improved if the correction for the relative velocity between the fluid and the sphere is made. The advantages of this technique are its simplicity, its relatively small contamination problem, its low cost, and its potential to be used in a wide range of flow conditions.

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The total-count technique: A new principle in flow measurement

Cited by 37 publications

References 2 publications

Analysis of Residence Time in the Measurement of Radon Activity by Passive Diffusion in an Open Volume: A Micro-Statistical Approach

Analysis of Residence Time in the Measurement of Radon Activity by Passive Diffusion in an Open Volume: A Micro-Statistical Approach

CHANNEL DISCHARGE MEASUREMENT BY THERMODILUTION¹

Velocity Measurement with Radioactive Spheres

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The total-count technique: A new principle in flow measurement

Cited by 37 publications

References 2 publications

Analysis of Residence Time in the Measurement of Radon Activity by Passive Diffusion in an Open Volume: A Micro-Statistical Approach

Analysis of Residence Time in the Measurement of Radon Activity by Passive Diffusion in an Open Volume: A Micro-Statistical Approach

CHANNEL DISCHARGE MEASUREMENT BY THERMODILUTION1

Velocity Measurement with Radioactive Spheres

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CHANNEL DISCHARGE MEASUREMENT BY THERMODILUTION¹