Characteristics of time-varying intracranial pressure on blood flow through cerebral artery: A fluid-structure interaction approach.

Elevated intracranial pressure is a major contributor to morbidity and mortality in severe head injuries. Wall shear stresses in the artery can be affected by increased intracranial pressures and may lead to the formation of cerebral aneurysms. Earlier research on cerebral arteries and aneurysms involves using constant mean intracranial pressure values.

Movable fiber probe for gas-phase laser-induced breakdown spectroscopy.

A movable probe that fiber couples both the beam delivery and the signal collection functions of gas-phase laser-induced breakdown spectroscopy (LIBS) measurements was evaluated. The adjustable probe was used to investigate the effect of delivery fiber curvature on plasma characteristics and the associated effect on LIBS spectra and to further identify issues remaining to facilitate fully fiber-coupled gas-phase LIBS measurements. LIBS data were collected from lean methane-air mixtures of various equivalence ratios and spectroscopically analyzed to establish the ability to determine relative fuel-air ratio.

Fiber-optic spark delivery for gas-phase laser-induced breakdown spectroscopy.

This article reports what are to the authors' knowledge the first gas-phase laser-induced breakdown spectroscopy (LIBS) measurements using a fiber-optically delivered spark. A silver- and polymer-coated hollow fiber delivered high-energy nanosecond 1064 nm Nd:YAG laser pulses, which were focused to generate high-energy-density plasmas in ultra-lean methane-air mixtures. Emissions from these plasmas were collected and spectroscopically analyzed to quantify relative fuel-to-air ratio.

Miniature rainbow schlieren deflectometry system for quantitative measurements in microjets and flames.

Recent interest in small-scale flow devices has created the need for miniature instruments capable of measuring scalar flow properties with high spatial resolution. We present a miniature rainbow schlieren deflectometry system to nonintrusively obtain quantitative species concentration and temperature data across the whole field. The optical layout of the miniature system is similar to that of a macroscale system, although the field of view is smaller by an order of magnitude.

High-intensity rocket noise: nonlinear propagation, atmospheric absorption, and characterization.

Analyses of rocket noise data measured at far-field locations during the launch of a large rocket and a smaller rocket are presented. Weak shocks are present in all of the data sets. In order to characterize these shocks, those segments of the waveforms where the acoustic pressure is increasing are isolated and the rate of increase in pressure plotted versus magnitude of pressure rise.