Laser driven shockwaves from nanosecond pulsed lasers were evaluated for pressure magnitude and duration using photon Doppler velocimetry (PDV). Specific investigations performed on Ti-6Al-4V alloys 7085-T7651 aluminum with laser full-width half-max pulse lengths ranging 6 to 20 ns intensities of 2–10 GW/cm2. The rear surface velocity data obtained a heterodyne PDV system an automated signal pr...

Laser vibration sensing provides a sensitive non-contact means of measuring vibrations of objects. These measurements are used in industrial quality control and wear monitoring as well as the analysis of the vibrational characteristics of objects. In laser vibrometry, the surface motion is monitored by heterodyne laser Doppler velocimetry, and the received heterodyne signal is sampled to produc...

BACKGROUND Intrauterine growth restriction /retardation (IUGR) is defined as birth weight below the 10th percentile for a given gestational age. Placental insufficiency is the primary cause of intrauterine growth retardation in normally formed fetuses and can be identified using umbilical artery Doppler velocimetry which is a non-invasive technique. The objective of this study was to compare pe...

Experimental observations of a purely elastic flow instability occurring in the lid-driven cavity flow of two semi-dilute polymer solutions are reported and the effect of cavity aspect ratio on the dynamical structure of the unstable flow is quantitatively investigated. The spatial and temporal characteristics of the secondary flow are measured using flow visualization, laser Doppler velocimetr...

Self-mixing laser sensors require few components and can be used to measure velocity. The self-mixing laser sensor consists of a laser emitting a beam focused onto a rough target that scatters the beam with some of the emission re-entering the laser cavity. This 'self-mixing' causes measurable interferometric modulation of the laser output power that leads to a periodic Doppler signal spectrum ...

PURPOSE There is a long-standing interest in the study of retinal blood flow in humans. In the recent years techniques have been established to measure retinal perfusion based on optical coherence tomography (OCT). In the present study we used a technique called dual-beam bidirectional Doppler Fourier-domain optical coherence tomography (FD-OCT) to characterize the effects of 100% oxygen breath...

Purpose: To evaluate the effects of enoxaparin and unfractionated heparin (UFH) administered in prophylactic and therapeutic doses on fetal vessels in healthy pregnant Wistar rats, according to Doppler velocimetry measurements. Methods: Fifty animals were assigned to one of five groups: controls (saline), prophylactic and therapeutic enoxaparin (1 and 2 mg/kg/day, respectively), and prophyl...

The authors implied that the abnormal uterine artery Doppler velocimetry is one of the risk markers for preeclampsia in the second or third trimester and that its abnormality is practically defined at 22–24 weeks as bilateral notching with mean resistance index (RI) > 0.55 (i.e., > 50th centile), unilateral notching with mean RI > 0.65 (> 90th centile), or no notching with mean RI > 0.70 (> 95t...

This paper is concerned with spatially-varying acoustic liner impedance in aeroacoustic ducts, the presence of a high sound pressure level. It shown that discontinuity leading order parameter definition variation. A large yields normal velocity variation, to significant nonlinear effects. An iterative numerical strategy proposed predict over liner. Bayesian inference process coupled surrogate m...