Knowledge Of Flow Rate Research Articles

Controlled nanoparticle synthesis via opposite-polarity electrospray pyrolysis

We report on a novel approach for the controlled synthesis of nanoparticles of uniform size and composition that is well suited to particle functionalization and scaleup. It relies on Electrospray Pyrolysis (ESP) in which charged, monodisperse liquid precursor droplets are first generated, then electrically neutralized by a second ES of opposite polarity and finally carried through a furnace for the synthesis of the desired nanoparticle, with each droplet serving as a nanoreactor in an environment of independently controlled temperature and residence time. We apply the approach to metal nitrates and synthesize a variety of metal oxides and mixed metal oxides, carbon coated nanoparticles, and hybrid structures of metal oxide-decorated graphene. In a proof-of-concept demonstration of inexpensive scale-up of the technique, we synthesize metal oxides using an array of ESs operating in parallel and a corona discharge to neutralize them, demonstrating the expected increase in nanoparticle production rate. Electrospray scaling laws and knowledge of flow rate(s) as well as physical properties of the liquid precursor(s) enable apriori determination of nanoparticle size, facilitating the selection of the synthesis protocol.

Acoustic profilers and urban pollutant fluxes

ABSTRACT A prudent management of networks, along with the minimisation of pollution discharged into receiving waters, requires an accurate knowledge of flow rates and pollutant loads conveyed in sewers. Conventional methods are based on well-known techniques, including acoustic devices and the sampling and analysis of total suspended solids. Although such methods yield satisfactory results for a typical gauging campaign, sensor implementation proves to be rather difficult. This study is intended to test the capabilities of acoustic Doppler profilers (ADP); the paper will present a PC-ADP profiler and the set of accompanying experiments. Initial results demonstrate great improvement offered by profiling techniques, in terms of both simultaneity and time savings.

20-, 23-, AND 25-GAUGE VITREOUS CUTTERS

The flow rate of nine vitreous cutters was tested in two different viscosity environments. Physical features of each probe, such as flexibility and internal lumen diameter, were measured. For each probe, a total of 26 aspiration tests were performed in two different liquids. The stiffness of the shaft of each probe was calculated by measuring the displacement of the tip of the probe under a known constant force. All the probes were dissected and the internal lumen diameter was measured. Significant differences in flow rates were observed among the three separate conditions, among the three different gauge groups (25-, 23-, and 20-gauge vitreous cutter), and also within each gauge group. Internal lumen diameters and probe stiffness characteristics are presented. Vacuum, internal lumen diameter, and duty cycle seem to be the critical features governing actual flow rate. Knowledge of flow rate and stiffness of the various probes may aid surgeons in making an educated choice and may improve patient care.

In vitro and in vivo rates of fluid flow through catheters in peripheral veins of dogs

Summary In vitro and in vivo fluid flow rates of 14-, 16-, 18-, and 20-gauge catheters at fluid heights of 0.91 and 1.75 m above the catheters were determined. Flow rates were significantly faster in vitro than in vivo, at a greater height, and with larger catheter radius. In vivo flow rates averaged 7% less than in vitro flow rates. Fluid flow increased approximately 50% for each gauge catheter when the height was raised from 0.91 to 1.75 m. Flow rates increased linearly with increasing catheter radius. The flow rate of each gauge of catheter was significantly different from flow rates of all other gauges that were used. In vivo flow rates for 14-, 16-, 18-, and 20-gauge catheters at fluid heights of 0.91 and 1.75 m were 137, 88, 75, and 45 ml/min and 206, 152, 114, and 75 ml/min, respectively. Knowledge of flow rates allows selection of a catheter gauge that will provide adequate volume loading for the size of patient being treated in the time needed.