Flow visualisation using tracer and particle techniques is well known to be susceptible to fallacious interpretation for unsteady shear flows. Recent experimental observations using these types of techniques have led to the conclusion that even for low Reynolds number flows, the vortex breakdown bubble in a torsionally driven cylinder is not closed and has an inflow/outflow asymmetry at its tai...

Determination of the distribution and quantity of non-aqueous phase liquids (NAPL) in the subsurface requires accurate evaluation of the effective parameters governing flow in porous media. A great deal of the work done towards the development of effective parameters has focused on analysis techniques for adapting parameters determined from a small-scale to a fieldscale system. These techniques...

Tracer-particles, massless particles that are advected throughout the flow domain, are an important factor in computational solutions. The utility of tracer-particles, which sample and report relevant solution data, is predicated upon an accurate advection algorithm. The objective of this research was to investigate the ability of existing techniques, physical-space and logical-space advection,...

ansi/ashrae 110-95 protocol is a widely acceptable method to assess the performance of laboratory hoods. in this test, sulfur hexafluoride (sf6) is applied as a tracer gas to quantitatively evaluate the performance of laboratory hoods. the environmentally hostile characteristics of sf6 as well as its cost are the major concerns. in the present study, the substitution of ethylene with sf6 in the...

Rapid multi-tracer PET aims to image two or more tracers in a single scan, simultaneously characterizing multiple aspects of physiology and function without the need for repeat imaging visits. Using dynamic imaging with staggered injections, constraints on the kinetic behavior of each tracer are applied to recover individual-tracer measures from the multi-tracer PET signal. The ability to rapid...

Abstract. The development and validation of management practices to mitigate greenhouse gas (GHG) emissions from livestock require accurate emission measurements. This study assessed the accuracy a practical inverse dispersion modelling (IDM) technique quantify methane (CH4) emitted small cattle herd (16 animals) confined 63 m × 60 experimental pen. IDM calculates increase in CH4 concentration ...

conclusions the results of this study led to the identification of many of the errors and conditions that affect the performance of controllers, providing the ability to define safety and ergonomic interventions to reduce the risk of human error. therefore, the results of this study can be a basis for planning atm to prioritize prevention programs and safety enhancement results the analysis of ...