Flow Characteristics of Closed Loop High PRF E-Beam or X-ray-Assisted Discharge Exciplex Laser

1984 ◽  
pp. 375-382
Author(s):  
S. M. Fournier ◽  
M. L. Sentis ◽  
B. M. Forestier ◽  
B. L. Fontaine
Keyword(s):  
Closed Loop ◽  
Flow Characteristics ◽  
X Ray

Techniques for arteriography and hydraulic analysis of coronary stenoses in unsedated dogs

1978 ◽  
Vol 235 (3) ◽  
pp. H350-H356 ◽  
Author(s):  
K. L. Gould ◽  
D. Lee ◽  
K. Lovgren
Keyword(s):  
Flow Velocity ◽  
Coronary Flow ◽  
Flow Characteristics ◽  
Doppler Velocity ◽  
Coronary Flow Velocity ◽  
X Ray ◽  
Pressure Losses ◽  
Coronary Stenoses ◽  
Velocity Pressure ◽  
Perivascular Cuff

This report describes techniques for obtaining pressure flow characteristics and arteriograms of controlled coronary stenoses in unsedated, trained dogs. Coronary flow velocity was recorded by calibrated Doppler velocity transducers linear to three times maximum coronary flow velocity. Pressure losses across stenoses were measured by a differential pressure transducer through small catheters implanted in the distal and proximal left circumflex coronary artery or ascending aorta, a system that was linear within +/-5% to 30 Hz. Coronary stenoses were produced by saline-filled, perivascular cuff constrictors inflated to constant pressure by a pressure regulator. Catheters were implanted in the pulmonary artery for injection of intravenous drugs or diffusible radionuclides and in the left atrium for injection of radionuclide microspheres. Contrast medium was injected through the proximal coronary catheter, and high-resolution arteriograms were obtained by single-spot filming on ultra detail X-ray film and cassettes at end diastole by triggering X-ray exposures from the electrocardiogram. In 13 dogs studied consecutively, the surgical mortality was 15.4%. All implanted instruments functioned for an average of 8 wk per dog.

Wavefront Closed-Loop Correction for X-Ray Microfocusing Active Optics

2007 ◽  
Author(s):  
Pascal Mercère ◽  
Mourad Idir ◽  
Thierry Moreno ◽  
Gilles Cauchon ◽  
Guillaume Dovillaire ◽  
...  
Keyword(s):  
Closed Loop ◽  
Loop Correction ◽  
Active Optics ◽  
X Ray

Dynamic Modelling and Performance of a Two Stage Piezoelectric Servovalve

2016 ◽  
Author(s):  
Johan Persson ◽  
Andrew R. Plummer ◽  
Christopher R. Bowen ◽  
Phil L. Elliott
Keyword(s):  
Closed Loop ◽  
Dynamic Modelling ◽  
Flow Characteristics ◽  
The Other ◽  
Step Response ◽  
Hydraulic Fluid ◽  
Two Stage ◽  
Second Stage ◽  
And Performance ◽  
Spool Valve

This paper describes the design, simulation and testing of a piezoelectrically-actuated two stage spool valve. The first stage is a small spool controlled by a piezoelectric ring bender and the second stage is a closed loop position controlled main spool. A dynamic mathematical model of the valve has been derived. Step response tests for both the first stage and second stage are presented, and experimental second stage frequency response results are shown. The mathematical models for the amplifier, first stage and second stage spool behaviour are validated against experimental data. The second stage spool behaviour is found to be very sensitive to the first stage flow characteristics. In addition, the displacement of the hydraulic fluid by the piezoelectric ring bender, from one side of the piezoelectric ring bender to the other, had a significant impact on the valve characteristics.

scholarly journals Optimization of X-ray Tube Voltage to Improve the Precision of Two Phase Flow Meters Used in Petroleum Industry

2021 ◽  
Vol 13 (24) ◽  
pp. 13622
Author(s):  
Abdullah K. Alanazi ◽  
Seyed Mehdi Alizadeh ◽  
Karina Shamilyevna Nurgalieva ◽  
John William Grimaldo Guerrero ◽  
Hala M. Abo-Dief ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Detection System ◽  
Petroleum Industry ◽  
Flow Characteristics ◽  
Absolute Error ◽  
Phase Flow ◽  
Tube Voltage ◽  
Two Phase ◽  
X Ray ◽  
Feature Extraction Method

To the best knowledge of the authors, in all the former studies, a fixed value of X-ray tube voltage has been used for investigating gas–liquid two-phase flow characteristics, while the energy of emitted X-ray radiations that depends on the tube voltage can significantly affect the measurement precision of the system. The purpose of present study is to find the optimum tube voltage to increase the accuracy and efficiency of an intelligent X-ray radiation-based two-phase flow meter. The detection system consists of an industrial X-ray tube and one detector located on either side of a steel pipe. Tube voltages in the range of 125–300 kV with a step of 25 kV were investigated. For each tube voltage, different gas volume percentages (GVPs) in the range of 10–90% with a step of 5% were modeled. A feature extraction method was performed on the output signals of the detector in every case, and the obtained matrixes were applied to the designed radial basis function neural networks (RBFNNs). The desired output of the networks was GVP. The precision of the networks in every voltage and every number of neurons in the hidden layer were obtained. The results showed that 225 kV tube voltage is the optimum voltage for this purpose. The obtained mean absolute error (MAE) for this case is less than 0.05, which demonstrates the very high precision of the metering system with an optimum X-ray tube voltage.

scholarly journals Topological Charge of Soft X-ray Vortex Beam Determined by Inline Holography

2021 ◽  
Author(s):  
Yuta Ishii ◽  
Hironori Nakao ◽  
Masaichiro Mizumaki ◽  
Yusuke Wakabayashi ◽  
Taka-hisa Arima ◽  
...  
Keyword(s):  
Topological Charge ◽  
Closed Loop ◽  
Fresnel Zone ◽  
Topological Defects ◽  
Vortex Beam ◽  
Magnetic Texture ◽  
X Ray ◽  
Pair Annihilation ◽  
Propagation Axis ◽  
Present Technique

Abstract A Laguerre–Gaussian (LG) vortex beam having a spiral wavefront can be characterized by its topological charge (TC). The TC gives the number of times that the beam phase passes through the interval [0, 2π] following a closed loop surrounding the propagation axis. Here, the TC of soft X-ray vortex beams is determined using the in-line holography technique, where interference between vortex waves produced from a fork grating and divergent waves from a Fresnel zone plate is observed as a holographic image. The analyses revealed the phase distributions and the TC for the LG vortex waves, which reflects topological number of the fork gratings, as well as for the Hermite–Gaussian (HG) mode waves generated from the other gratings. We also conducted a simulation of the present technique for pair annihilation of topological defects in a magnetic texture. These results may pave the way for development of probes capable of characterizing the topological numbers of magnetic defects.

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