Uncertainty analysis of vibration measurements of tools inside fluids by laser Doppler techniques

1998 ◽  
Author(s):  
Roberto Marsili ◽  
Luciano Pizzoni ◽  
Gianluca L. Rossi
Keyword(s):  
Uncertainty Analysis ◽  
Laser Doppler ◽  
Vibration Measurements ◽  
Doppler Techniques

Vibration measurements of tools inside fluids by laser Doppler techniques: uncertainty analysis

Measurement ◽  
2000 ◽  
Vol 27 (2) ◽  
pp. 111-120 ◽  
Author(s):  
Roberto Marsili ◽  
Luciano Pizzoni ◽  
Gianluca Rossi
Keyword(s):  
Uncertainty Analysis ◽  
Laser Doppler ◽  
Vibration Measurements ◽  
Doppler Techniques

Reflex control of the cutaneous circulation during passive body core heating in humans

2000 ◽  
Vol 88 (5) ◽  
pp. 1756-1764 ◽  
Author(s):  
Jochen K. Peters ◽  
Takeshi Nishiyasu ◽  
Gary W. Mack
Keyword(s):  
Blood Pressure ◽  
Heat Stress ◽  
Lower Body Negative Pressure ◽  
Venous Pressure ◽  
Laser Doppler ◽  
Vascular Conductance ◽  
Arterial Blood ◽  
Body Core ◽  
Doppler Techniques ◽  
The Impact

The impact of body core heating on the interaction between the cutaneous and central circulation during blood pressure challenges was examined in eight adults. Subjects were exposed to −10 to −90 mmHg lower body negative pressure (LBNP) in thermoneutral conditions and −10 to −60 mmHg LBNP during heat stress. We measured forearm vascular conductance (FVC; ml ⋅ min−1 ⋅ 100 ml−1 ⋅ mmHg−1) by plethysmography; cutaneous vascular conductance (CVC) by laser-Doppler techniques; and central venous pressure, arterial blood pressure, and cardiac output by impedance cardiography. Heat stress increased FVC from 5.7 ± 0.9 to 18.8 ± 1.3 conductance units (CU) and CVC from 0.21 ± 0.07 to 1.02 ± 0.20 CU. The FVC-CVP relationship was linear over the entire range of LBNP and was shifted upward during heat stress with a slope increase from 0.46 ± 0.10 to 1.57 ± 0.3 CU/mmHg CVP ( P < 0.05). Resting CVP was lower during heat stress (6.3 ± 0.6 vs. 7.7 ± 0.6 mmHg; P < 0.05) but fell to similar levels during LBNP as in normothermic conditions. Data analysis indicates an increased capacity, but not sensitivity, of peripheral baroreflex responses during heat stress. Laser-Doppler techniques detected thermoregulatory responses in the skin, but no significant change in CVC occurred during mild-to-moderate LBNP. Interestingly, very high levels of LBNP produced cutaneous vasodilation in some subjects.

SCANNING LASER DOPPLER TECHNIQUES FOR VIBRATION TESTING

2008 ◽  
Vol 16 (6) ◽  
pp. 21-26 ◽  
Author(s):  
P. Sriram ◽  
J. I. Craig ◽  
S. Hanagud
Keyword(s):  
Laser Doppler ◽  
Scanning Laser ◽  
Vibration Testing ◽  
Doppler Techniques
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