We show clear experimental evidence that in the laminar flow regime, there is a continuous redistribution of population on different vibrorotational energy levels as the flow rate increases. Such redistribution comes to an abrupt stop when the flow changes to turbulence. The population distribution then remains almost unchanged even up to the flow rate 10 times the laminar to turbulent transiti...

In an earlier paper in Entropy [1] we hypothesized that the entropy generation rate is the driving force for boundary layer transition from laminar to turbulent flow. Subsequently, with our colleagues we have examined the prediction of entropy generation during such transitions [2,3]. We found that reasonable predictions for engineering purposes could be obtained for flows with negligible strea...

the present study aimed to investigate two numerical solutions of the navier-stokes equations. for this purpose, the mentioned flow equations were written in two different formulations, namely (i) velocity-pressure and (ii) vorticity-stream function formulations. solution algorithms and boundary conditions were presented for both formulations and the efficiency of each formulation was investiga...

The National Institute of Standards and Technology (NIST) has performed calibrations of gas flowmeters using piston and bell provers for three decades. Most of the meters calibrated have been either critical flow nozzles or laminar flowmeters since these meter types are generally chosen as the working standards or transfer standards by other flow calibration laboratories. Often the same meters ...

A prospective study of the use of a laminar flow cabinet, an exhaust-ventilated safety hood, and the open bench for the microbiological examination of blood is described. Blood samples from 1600 patients were subcultured on the open bench, 2700 in a safety hood, and 2607 in a laminar flow cabinet. Use of the laminar flow cabinet produced a significantly greater level of contamination than the o...

PURPOSE To evaluate the sterility of the sterile surgical helmet system (SSHS) during elective total hip and knee arthroplasty in theatres with (n=20) and without (n=20) laminar flow. METHODS Three surgeons performed 14 total knee arthroplasties (TKAs) and 6 total hip arthroplasties (THAs) in a laminar flow theatre and 15 TKAs and 5 THAs in a non-laminar flow theatre. An SSHS was used in all ...

Disturbed flow can eliminate the alignment of endothelial cells in the direction of laminar flow, and significantly impacts on atherosclerosis in collateral arteries near the bifurcation and high curvature regions. While shear stress induced Rac polarity has been shown to play crucial roles in cell polarity and migration, little is known about the spatiotemporal map of Rac under disturbed flow,...

OBJECTIVE Laminar shear stress plays critical roles in vascular homeostasis and exerts various metabolic effects on endothelial cells (ECs). Stearoyl-CoA desaturase-1 (SCD1), which catalyzes the biosynthesis of monounsaturated fatty acids, affects the lipid composition and fluidity of the cell membrane. Thus, we examined the effect of laminar flow on SCD1 expression in ECs. METHODS A flow cha...