The Damage Capacity of Cavitating Flow From Pulse Height Analysis

1989 ◽  
Vol 111 (4) ◽  
pp. 502-509 ◽  
Author(s):  
S. A. Fry
Keyword(s):  
Circular Cylinder ◽  
Pulse Height ◽  
Pulse Amplitude ◽  
Flow Conditions ◽  
Noise Levels ◽  
Linear Calibration ◽  
Cavitation Noise ◽  
Pulse Height Analyser ◽  
Pulse Height Analysis ◽  
Digital Pulse

Digital pulse amplitude acquisition systems are reviewed and an analogue pulse height analyser (PHA) is described. Cavitation experiments are reported in which pressure pulses in the liquid (water) are picked up by a flush mounted pressure transducer and measured using the PHA. Tests were carried out on two cavitation sources: a 60 deg symmetric wedge and a circular cylinder. Despite generating similar r.m.s. noise levels the wedge is 21 times as damaging as the circular cylinder at peak noise flow conditions (at V = 16 m/s). By imposing thresholds on the spectra parameters it had been possible to find a linear calibration beween noise and erosion applicable to both cavitation sources over a range of flow velocities. A good correlation between cavitation noise and erosion was found by simply measuring the number of pulses above a suitable threshold.

Energy-dependent dead-time correction in digital pulse processors applied to silicon drift detector's X-ray spectra

2018 ◽  
Vol 25 (2) ◽  
pp. 484-495 ◽  
Author(s):  
Suelen F. Barros ◽  
Vito R. Vanin ◽  
Alexandre A. Malafronte ◽  
Nora L. Maidana ◽  
Marcos N. Martins
Keyword(s):  
Dead Time ◽  
Pulse Height ◽  
Height Distribution ◽  
Pulse Height Distribution ◽  
Dead Time Correction ◽  
Time Model ◽  
X Ray ◽  
Digital Pulse ◽  
Analytical Correction ◽  
Energy Dependent

Dead-time effects in X-ray spectra taken with a digital pulse processor and a silicon drift detector were investigated when the number of events at the low-energy end of the spectrum was more than half of the total, at counting rates up to 56 kHz. It was found that dead-time losses in the spectra are energy dependent and an analytical correction for this effect, which takes into account pulse pile-up, is proposed. This and the usual models have been applied to experimental measurements, evaluating the dead-time fraction either from the calculations or using the value given by the detector acquisition system. The energy-dependent dead-time model proposed fits accurately the experimental energy spectra in the range of counting rates explored in this work. A selection chart of the simplest mathematical model able to correct the pulse-height distribution according to counting rate and energy spectrum characteristics is included.

scholarly journals Arterial Digital Pulse Photoplethysmography in Patients with Suspected Thoracic Outlet Syndrome: A Study of the “Ca+Pra” Maneuver

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1128
Author(s):  
Jeanne Hersant ◽  
Pierre Ramondou ◽  
Francine Thouveny ◽  
Mickael Daligault ◽  
Mathieu Feuilloy ◽  
...  
Keyword(s):  
Thoracic Outlet Syndrome ◽  
Pulse Amplitude ◽  
Receiver Operating Characteristics ◽  
Upper Limbs ◽  
Operating Characteristics ◽  
Digital Pulse ◽  
Arterial Inflow ◽  
Receiver Operating

The level of pulse amplitude (PA) change in arterial digital pulse plethysmography (A-PPG) that should be used to diagnose thoracic outlet syndrome (TOS) is debated. We hypothesized that a modification of the Roos test (by moving the arms forward, mimicking a prayer position (“Pra”)) releasing an eventual compression that occurs in the surrender/candlestick position (“Ca”) would facilitate interpretation of A-PPG results. In 52 subjects, we determined the optimal PA change from rest to predict compression at imaging (ultrasonography +/− angiography) with receiver operating characteristics (ROC). “Pra”-PA was set as 100%, and PA was expressed in normalized amplitude (NA) units. Imaging found arterial compression in 23 upper limbs. The area under ROC was 0.765 ± 0.065 (p < 0.0001), resulting in a 91.4% sensitivity and a 60.9% specificity for an increase of fewer than 3 NA from rest during “Ca”, while results were 17.4% and 98.8%, respectively, for the 75% PA decrease previously proposed in the literature. A-PPG during a “Ca+Pra” test provides demonstrable proof of inflow impairment and increases the sensitivity of A-PPG for the detection of arterial compression as determined by imaging. The absence of an increase in PA during the “Ca” phase of the “Ca+Pra” maneuver should be considered indicative of arterial inflow impairment.

Multiparameter pulse-height analysis with a PDP-8/e computer

1974 ◽  
Vol 121 (3) ◽  
pp. 573-580 ◽  
Author(s):  
N.S. Kendrick ◽  
D.A. McClure
Keyword(s):  
Pulse Height ◽  
Pulse Height Analysis

A new soft x-ray pulse height analysis array in the HL-2A tokamak

2009 ◽  
Vol 80 (12) ◽  
pp. 126104 ◽  
Author(s):  
Y. P. Zhang ◽  
Yi Liu ◽  
J. W. Yang ◽  
X. Y. Song ◽  
M. Liao ◽  
...  
Keyword(s):  
Pulse Height ◽  
X Ray ◽  
Pulse Height Analysis

scholarly journals Plasma impurities observed by a pulse height analysis diagnostic during the divertor campaign of the Wendelstein 7-X stellarator

2018 ◽  
Vol 89 (10) ◽  
pp. 10F111 ◽  
Author(s):  
M. Kubkowska ◽  
A. Czarnecka ◽  
T. Fornal ◽  
M. Gruca ◽  
S. Jabłoński ◽  
...  
Keyword(s):  
Pulse Height ◽  
Pulse Height Analysis ◽  
Plasma Impurities
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