Laser Doppler Measurements of Localized Pulsatile Fluid Velocity

1971 ◽  
Vol BME-18 (6) ◽  
pp. 416-420 ◽  
Author(s):  
Satsuki Morikawa ◽  
Otto Lanz ◽  
Curtis C. Johnson
Keyword(s):  
Fluid Velocity ◽  
Laser Doppler

Laser vibrometry for combustion diagnostics in thermoacoustic research

2015 ◽  
Vol 82 (11) ◽  
Author(s):  
Johannes Peterleithner ◽  
Jakob Woisetschläger
Keyword(s):  
Heat Release ◽  
Density Fluctuation ◽  
Fluid Velocity ◽  
Density Fluctuations ◽  
Laser Doppler ◽  
Acoustic Oscillations ◽  
Laser Vibrometry ◽  
Laser Doppler Vibrometry ◽  
Novel Technique ◽  
Combustion Diagnostics

AbstractA novel technique for time- and space-resolved measurement of density fluctuation is presented. It is nonintrusive and based on laser Doppler vibrometry. The density fluctuations reveal information on dynamic heat release and fluid velocity. The significance of this technique is proven by recording thermo-acoustic oscillations in a model combustor.

Uncomplicated Setting Apparatus for Measurement of Fluid Flow Rate Using Laser Doppler Technique: Physics Teaching

2013 ◽  
Vol 770 ◽  
pp. 366-369
Author(s):  
Chatchalong Apiputikul ◽  
Kheamrutai Thamaphat ◽  
Monrudee Ranusawad ◽  
Pichet Limsuwan
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Doppler Shift ◽  
Laser Doppler Anemometry ◽  
Scattered Light ◽  
Fluid Velocity ◽  
Water Flow Rate ◽  
Processing System ◽  
Laser Doppler ◽  
Single Observation

Laser Doppler velocimetry (LDV) or laser Doppler anemometry (LDA) is the technique of using the Doppler shift in a laser beam to determine the fluid velocity. In this work, dual beam mode (two incident beams, single observation location) was selected to use. A cost effective and easy module for measurement of water flow rate was designed and constructed. A He-Ne laser with a wavelength of 632.8 nm was used as a light source. The laser was passed through a beam splitter and divided into two beams with identical intensity and coherence. Subsequently, the two laser beams travelled to a focusing lens with a focal length of 100 mm and focused on a center of water flow channel in quartz cuvette with a dimension of 1 × 1 × 5 cm3. The beam angle was set at 4.96°. When the seeding particles, bubbles and microorganism in water, were moving through the intersection point of two beams, the light was scattered. The scattered light was collected by photodetector connected to processing system. The frequency of scatterred light is shifted according to the Doppler shift relations due to effect of Rayleigh scattering. The water flow rate can be calculated from Doppler shift frequency.

Laser-Doppler measurements of concentration and velocity of moving blood cells in rat cerebral circulation

1997 ◽  
Vol 160 (1) ◽  
pp. 123-132
Author(s):  
C. BARFOD ◽  
N. AKGÖREN ◽  
M. FABRICIUS ◽  
U. DIRNAGL ◽  
M. LAURITZEN
Keyword(s):  
Blood Cells ◽  
Cerebral Circulation ◽  
Laser Doppler

The response of skin perfusion and of rheological and immunological variables to intravenous prostanoid administration in Raynaud’s phenomenon secondary to collagenosis

VASA ◽  
2005 ◽  
Vol 34 (4) ◽  
pp. 243-249 ◽  
Author(s):  
Drinda ◽  
Neumann ◽  
Pöhlmann ◽  
Vogelsang ◽  
Stein ◽  
...  
Keyword(s):  
Laser Doppler Flowmetry ◽  
Raynaud’S Phenomenon ◽  
Raynaud's Phenomenon ◽  
Plasma Viscosity ◽  
Laser Doppler ◽  
Erythrocyte Aggregation ◽  
Control Group ◽  
Long Term Effects ◽  
Doppler Flowmetry

Background: Prostanoids are used in the treatment of Raynaud’s phenomenon and acral perfusion disorders secondary to collagenosis. In subjective terms, intravenous administration of these agents produces success in more than 50% of patients. The therapeutic outcome of clinical administration of alprostadil or iloprost may vary from individual to individual. Patients and methods: The following variables were analysed in a cross-over study in 27 patients with collagenosis and Raynaud’s phenomenon: plasma viscosity and erythrocyte aggregation (rheological variables), partial pressure of oxygen and laser Doppler flowmetry in the finger region, and lymphocyte phenotyping and interleukin (IL) determinations (immunological variables). Results: Laser Doppler flowmetry revealed significant differences between patients with secondary Raynaud’s phenomenon and a control group of 25 healthy subjects. Laser Doppler readings did not change significantly as a result of the treatments. Therapy with iloprost produced a reduction in IL-1beta, L-selectin (CD 62 L) and IL-6. Conclusion: The change in immunological variables due to iloprost may explain the long-term effects of prostaglandins in the treatment of Raynaud’s phenomenon. From our results it is not possible to infer any preference for iloprost or alprostadil.

Exploration par anémométrie laser Doppler de l'écoulement dans une pompe hélico-axiale

2001 ◽  
pp. 34-39 ◽  
Author(s):  
M. El Hajem ◽  
R. Morel ◽  
J. Y. Champagne ◽  
R. Vilagines ◽  
P. Pagnier
Keyword(s):  
Laser Doppler

Veränderungen der Mikrozirkulation bei Patienten mit Unterschenkelerysipelen vor, während und nach antibiotischer Therapie

Phlebologie ◽  
1998 ◽  
Vol 27 (04) ◽  
pp. 131-137
Author(s):  
S. Roszinski ◽  
W. Schmeller ◽  
S. Kock
Keyword(s):  
Laser Doppler ◽  
Doppler Flux

ZusammenfassungBei 12 Patienten mit Erysipelen am Unterschenkel erfolgten Messungen der Mikrozirkulation in Ruhe und bei hämodynamischen Funktionstests. Bestimmt wurden: Hauttemperatur, Erythemstärke (a-Wert der Colorimetrie), transkutaner Sauerstoffpartialdruck (tcPO2 bei 37° C und 44° C Elektrodentemperatur) sowie Laser-Doppler-Flux (LDF). Die Messungen wurden im Zentrum der Erysipele und an den gesunden kontralateralen Beinen zu Beginn, während und eine Woche nach Ende der Antibiotikatherapie durchgeführt. Zum Zeitpunkt der akuten Entzündung zeigten alle Parameter deutliche Veränderungen; diese wiesen Reaktionsmuster auf, wie sie auch bei Dermatosen mit morphologischen Veränderungen des Kapillarsystems gefunden werden. Nach klinischer Abheilung wiesen tcPO2 bei 37° C und Laser-Doppler-Flux sowohl in Ruhe als auch bei den Funktionstests noch deutliche Veränderungen auf.

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