CO2 Laser Measurements on Shock Fronts

1974 ◽  
Vol 52 (21) ◽  
pp. 2083-2087 ◽  
Author(s):  
A. R. Strilchuk ◽  
A. A. Offenberger
Keyword(s):  
Co2 Laser ◽  
Atmospheric Pressure ◽  
Low Pressure ◽  
Shock Velocity ◽  
Piezoelectric Transducers ◽  
Angle Of Incidence ◽  
Laser Measurements ◽  
Heterodyne Technique ◽  
Shock Fronts ◽  
Good Agreement

CO2 laser measurements on reflectivity of shock fronts in N2, Ar, and CO2 at atmospheric pressure and N2 at low pressure are presented as well as results of shock velocity determination using a heterodyne technique. The measured and expected variation of reflectivity with angle of incidence show good agreement as do velocities compared with those determined using piezoelectric transducers.

scholarly journals Impedance Spectroscopy of Lead-Free Ferroelectric Coatings

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 221
Author(s):  
Mariya Aleksandrova ◽  
Ivailo Pandiev
Keyword(s):  
Composite Coatings ◽  
Electrical Circuit ◽  
Ferroelectric Materials ◽  
Piezoelectric Transducers ◽  
Lead Free ◽  
Electrical Behavior ◽  
Oxide Composite ◽  
Before And After ◽  
Frequency Dependences ◽  
Good Agreement

This paper presents impedance measurements of ferroelectric structures involving lead-free oxide and polymer-oxide composite coatings for sensing and energy harvesting applications. Three different ferroelectric materials grown by conventional microfabrication technologies on solid or flexible substrates are investigated for their basic resonant characteristics. Equivalent electrical circuit models are applied to all cases to explain the electrical behavior of the structures, according to the materials type and thickness. The analytical results show good agreement with the experiments carried out on a basic types of excited thin-film piezoelectric transducers. Additionally, temperature and frequency dependences of the dielectric permittivity and losses are measured for the polymer-oxide composite device in relation with the surface morphology before and after introduction of the polymer to the functional film.

scholarly journals Experimental study on the effect of spray cone angle on the characteristics of horizontal jet spray flame under sub-atmospheric pressure

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2941-2952 ◽  
Author(s):  
Kai Xie ◽  
Xingqi Qiu ◽  
Yunjing Cui ◽  
Jianxin Wang
Keyword(s):  
Atmospheric Pressure ◽  
Cone Angle ◽  
Flame Temperature ◽  
Normal Pressure ◽  
Low Pressure ◽  
Dimensionless Temperature ◽  
Thermal Imager ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Matlab Programming

The burning state of a plateau environment is attracting more and more attention. In this paper, in order to have a deeper scientific understanding of diesel spray combustion and the characteristics of a flame under different spray cone angles in a plateau environment, experiments were carried out in a low pressure chamber. The flame morphology was recorded by a high speed video instrument, and the temperature change was recorded by a thermal imager and thermocouples. The MATLAB programming was used to process the video image of the flame, and the probability of its binarization was calculated. The results indicate that the flame becomes longer and wider under different pressures with the same spray angle. The variation is more pronounced at a smaller spray taper angle. The flame uplifted height characteristic is mainly negatively related to the atmospheric pressure. According to the normalized flame temperature and the dimensionless horizontal projection, the length can be divided into three regions. In the region of buoyancy flame, the dimensionless temperature varies with sub-atmospheric pressure more than with normal pressure. In addition, under different spray cone angle conditions, the law of variation in the normalized flame temperature under sub-atmospheric pressure is exactly opposite to that under normal pressure. This study is of great significance to the scientific research on flames in a low pressure environment, and the design of different fuel nozzles for application in a plateau environment.

scholarly journals Characterization of Periodic Incoming Wakes in a Low-Pressure Turbine Cascade Test Section by Means of a Fast-Response Single Sensor Virtual Three-Hole Probe

2019 ◽  
Vol 4 (3) ◽  
pp. 26
Author(s):  
Julien Clinckemaillie ◽  
Tony Arts
Keyword(s):  
Total Pressure ◽  
High Speed ◽  
Control Volume ◽  
Low Pressure ◽  
Fast Response ◽  
Pressure Probe ◽  
Flow Angle ◽  
Low Pressure Turbine ◽  
Wide Range ◽  
Good Agreement

This paper aims at evaluating the characteristics of the wakes periodically shed by the rotating bars of a spoked-wheel type wake generator installed upstream of a high-speed low Reynolds linear low-pressure turbine blade cascade. Due to the very high bar passing frequency obtained with the rotating wake generator (fbar = 2.4−5.6 kHz), a fast-response pressure probe equipped with a single 350 mbar absolute Kulite sensor has been used. In order to measure the inlet flow angle fluctuations, an angular aerodynamic calibration of the probe allowed the use of the virtual three-hole mode; additionally, yielding yaw corrected periodic total pressure, static pressure and Mach number fluctuations. The results are presented for four bar passing frequencies (fbar = 2.4/3.2/4.6/5.6 kHz), each tested at three isentropic inlet Mach numbers M1,is = 0.26/0.34/0.41 and for Reynolds numbers varying between Re1,is = 40,000 and 58,000, thus covering a wide range of engine representative flow coefficients (ϕ = 0.44−1.60). The measured wake characteristics show fairly good agreement with the theory of fixed cylinders in a cross-flow and the evaluated total pressure losses and flow angle variations generated by the rotating bars show fairly good agreement with theoretical results obtained from a control volume analysis.

Experimental research of a multipass transverse excitation atmospheric-pressure CO2 laser

2013 ◽  
Vol 52 (4) ◽  
pp. 049701 ◽  
Author(s):  
Fei Liu ◽  
Johannes Rothe ◽  
Robert Horton ◽  
Alain Semet ◽  
Russell Evans ◽  
...  
Keyword(s):  
Experimental Research ◽  
Co2 Laser ◽  
Atmospheric Pressure ◽  
Transverse Excitation

scholarly journals Transfer of POCl3 diffusion processes from atmospheric pressure to high throughput low pressure

2018 ◽  
Author(s):  
Sabrina Lohmüller (née Werner) ◽  
Stefan Schmidt ◽  
Elmar Lohmüller ◽  
Alexander Piechulla ◽  
Udo Belledin ◽  
...  
Keyword(s):  
High Throughput ◽  
Atmospheric Pressure ◽  
Diffusion Processes ◽  
Low Pressure

Effect of CO2 Laser Beam Angle of Incidence in the Oral Cavity

1991 ◽  
Vol 9 (3) ◽  
pp. 209-213 ◽  
Author(s):  
Lajos Gáspár ◽  
Miklós Kásler ◽  
Mihály Orosz
Keyword(s):  
Oral Cavity ◽  
Laser Beam ◽  
Co2 Laser ◽  
Angle Of Incidence ◽  
Beam Angle
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