Woodchip humidity measurements using EM pulse propagation time

2012 ◽  
Author(s):  
Alessandro Cazzorla ◽  
Antonio Moschitta ◽  
Marco Dionigi ◽  
Paolo Carbone ◽  
Michele D'Amico ◽  
...  
Keyword(s):  
Pulse Propagation ◽  
Propagation Time ◽  
Humidity Measurements

Damage Evaluation in Smart Materials Using Time-Frequency Analysis

2011 ◽  
Vol 311-313 ◽  
pp. 2299-2306 ◽  
Author(s):  
Chin Kian Liew ◽  
Martin Veidt
Keyword(s):  
Smart Materials ◽  
Pulse Propagation ◽  
Guided Wave ◽  
Propagation Time ◽  
Damage Evaluation ◽  
Conditional Moment ◽  
Time Frequency ◽  
Reinforced Composite ◽  
Imaging Results ◽  
Present Information

An approach to identify damages in materials particularly aerospace composites has been developed based on application of wavelet analysis on guided wave transient signals. The wave response was convoluted against a suitable wavelet to present information in the time-frequency domain for baseline comparison of signals. By evaluating the time-frequency conditional moment, sensitive indices were computed to identify the presence of damage. Normalisation of these indices was found to be an important procedure to reduce measurement discrepancies from baseline comparison. Extending this further was the correlation of these parameters to pulse propagation time from actuator to sensor positions to generate a tomographic representation of the damage in the scanned material. These damage evaluation processes were investigated in an ultrasonic health monitoring system inspecting carbon fibre reinforced composite panels with simulated delamination. The imaging results displayed positive damage characterisation capabilities for implementation within the methodology of smart or intelligent materials.

scholarly journals Phase Error and Pulse Propagation Time of Parabolic Equation Method

2006 ◽  
Vol 33 (2) ◽  
pp. 97-105
Author(s):  
Jun NAOI ◽  
Ryoichi IWASE ◽  
Toshiaki KIKUCHI ◽  
Koich MIZUTANI
Keyword(s):  
Parabolic Equation ◽  
Pulse Propagation ◽  
Phase Error ◽  
Equation Method ◽  
Propagation Time ◽  
Parabolic Equation Method

scholarly journals Assimilation of atmospheric infrasound data to constrain tropospheric and stratospheric winds

2020 ◽  
Author(s):  
Javier Amezcua ◽  
Peter Nasholm ◽  
Marten Blixt ◽  
Andrew Charlton-Perez
Keyword(s):  
Ensemble Kalman Filter ◽  
Pulse Propagation ◽  
Atmospheric Model ◽  
Propagation Time ◽  
Wind Component ◽  
Atmospheric Models ◽  
Recording Station ◽  
Middle Atmospheric Dynamics ◽  
The Difference ◽  
Back Azimuth

<p>We use acoustical infrasound from explosions to probe an atmospheric wind component from the ground up to stratospheric altitudes. Planned explosions of old ammunition in Finland generate transient infrasound waves that travel through the atmosphere. These waves are partially reflected back towards the ground from stratospheric levels, and are detected at a receiver station located in northern Norway at 178 km almost due North from the explosion site. The difference between the true horizontal direction towards the source and the back-azimuth direction of the incoming infrasound wave-fronts, in combination with the pulse propagation time, are exploited to provide an estimate of the average cross-wind component in the penetrated atmosphere. <br>We perform offline assimilation experiments with an ensemble Kalman filter and these observations, using the ERA5 ensemble reanalysis atmospheric product as background (prior) for the wind at different vertical levels. Information from both sources is combined to obtain analysis (posterior) estimates of cross-winds at different vertical levels of the atmospheric slice between the explosion site and the recording station. The assimilation makes greatest impact at the 12-60 km levels, with some changes with respect to the prior of the order of 0.1-1.0 m/s, which is a magnitude larger than the typical standard deviation of the ERA5 background. The reduction of background variance in the higher levels often reached 2-5%. <br>This is the first study demonstrating  techniques to implement assimilation of infrasound data into atmospheric models. It paves the way for further exploration in the use of infrasound  observations (especially natural and continuous sources) to probe the middle atmospheric dynamics and to assimilate these data into atmospheric model products.  </p>

scholarly journals CUFF-LESS MEASUREMENT OF BLOOD PRESSURE BY USING NEURAL NETWORKS

2021 ◽  
pp. 160-163
Author(s):  
Oleh Viunytskyi ◽  
Vyacheslav Shulgin ◽  
Alexander Totsky ◽  
Valery Sharonov
Keyword(s):  
Machine Learning ◽  
Blood Pressure ◽  
Pulse Propagation ◽  
Continuous Measurement ◽  
Propagation Time ◽  
New Approach ◽  
Estimation Algorithms ◽  
Individual Calibration ◽  
Blood Pressure Estimation ◽  
Electrocardiogram Ecg

This article attempts to consider a new approach to continuous measurement of blood pressure (BP), based on the pulse propagation time between two points of a blood vessel (PTT). The measuring of PTT based on the signal processing and analysis of the electrocardiogram (ECG), photoplethysmogram (PPG). The PTT-based blood pressure estimation algorithms, used by most authors, suggest their individual calibration for each patient. More flexible is a different approach - the use of machine learning. It is especially noted that the use of machine learning reduce the error in blood pressure measuring.

Nonlinear Pulse Propagation and Modulation Instability in Periodic Media with and without Defects

PIERS Online ◽  
2006 ◽  
Vol 2 (2) ◽  
pp. 177-181
Author(s):  
V. Grimalsky ◽  
Svetlana Koshevaya ◽  
Javier Sanchez-Mondragon ◽  
Margarita Tecpoyotl Torres ◽  
J. Escobedo Alatorre
Keyword(s):  
Pulse Propagation ◽  
Modulation Instability ◽  
Periodic Media ◽  
Nonlinear Pulse Propagation
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