Microwave Methods for Cryogenic Liquid and Slush Instrumentation

Ellerbruch,

doi:10.1109/tim.1970.4313938

Cited by 10 publications

(3 citation statements)

References 4 publications

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“…For the non-differential type densimeter, the sensitivities are 0.284 pF at 500 kHz and 0.414 pF at 1.0 MHz respectively, indicating that the densimeter sensitivity increases with the frequency, corresponding to the theoretical analysis shown by in Eq. (7). The sensitivity of the differential type densimeter is 3.718 pF at 1.0 MHz, which is much higher than that of the non-differential type and slightly higher than the theoretical value of 3.156 pF, calculated by Eq.…”

Section: Influence Of the Frequency On The Densimeter Sensitivitymentioning

confidence: 57%

“…So far, various techniques have been developed to determine the densities of slush fluids, mainly including microwave method, gammaray method and capacitance method. Ellerbruch [7] used microwave instruments to measure the density of slush hydrogen and obtained the uncertainty of less than ±2%. Due to the reflection of microwave by the inner wall of dewar, the wave-absorbent material is required to improve the measurement accuracy.…”

Section: Introductionmentioning

confidence: 99%

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Density determination of slush nitrogen by the improved capacitance-type densimeter

Jiang

Zhang

2011

Experimental Thermal and Fluid Science

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Section: Influence Of the Frequency On The Densimeter Sensitivitymentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Density determination of slush nitrogen by the improved capacitance-type densimeter

Jiang

Zhang

2011

Experimental Thermal and Fluid Science

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“…The concept of microwave sensor detection of solid mass flow was proposed in 1970 [12,13], and the feasibility of this technology was later studied by HAMID et al [14]. M ISA et al [15].…”

Section: Introductionmentioning

confidence: 99%

Design and testing of a microwave Doppler-based yield estimation system for machine-picked seed cotton

Li,

Feng,

Zhang

et al. 2024

Preprint

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Accurately obtaining crop yields is an important part of the precision agriculture technology system; with the increased mechanisation of cotton planting and harvesting, it has become particularly important to accurately obtain seed cotton yield data. In order to achieve accurate estimation of machine-picked seed cotton yield, this paper designs a machine-picked seed cotton yield estimation system based on microwave Doppler principle. Based on LabVIEW software, the signal acquisition circuit is designed; the power spectrum of the echo signal is estimated; the signal echo power is obtained; the relationship model between echo power and seed cotton mass is established by using multiple regression equations; and the reliability of the model is verified by using statistical methods. By adjusting the rotational speed of the fan, the wind speed at the inlet of the cotton pipeline was 10 m/s, 15 m/s and 20 m/s, and the yield estimation tests were carried out at the three wind speeds, and the data showed that the average absolute percentage errors of the estimation at the three wind speeds were 7.36%, 7.72% and 8.17%, and the mean squared errors were 2.699, 4.938 and 4.026, respectively. The test results show that the accuracy of seed cotton mass estimation under the three wind speeds basically meets the needs of the yield measurement system, and the systematic error of seed cotton yield estimation is the smallest when the wind speed is 10 m/s.

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Microwave radar sensor as solid flow counter

Isa

High Frequency Postgraduate Student Colloquium, 2004

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Absrruct: Microwave Radar Sensors (MRS) studies are usually based on the analysis of the frequency response of the reflected signal. A MRS system operating at I0.6GHz with computer integration has been built to study the signal characteristic of solid flows. Beans of hi4 in size have been used in this study. The amplitude of the reflected signal has been found to be useful in describing the flow characteristic. The amplitude response can be converted into a digital counter with the application of advance signal processing to eliminate noise and unwanted signal. In fact, the system not only counts the number of solids flowing but was also able to identify the size of the solids. Experimental results will be presented in this paper.

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Microwave Methods for Cryogenic Liquid and Slush Instrumentation

Cited by 10 publications

References 4 publications

Density determination of slush nitrogen by the improved capacitance-type densimeter

Density determination of slush nitrogen by the improved capacitance-type densimeter

Design and testing of a microwave Doppler-based yield estimation system for machine-picked seed cotton

Microwave radar sensor as solid flow counter

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