We propose a new experimental protocol to investigate the atmospheric dispersion of dense gas in wind-tunnel experiments. Simultaneous measurements concentration and velocity are performed by coupling flame ionisation detector (FID) hot-wire anemometer (HWA), whose probes located sufficiently close each other so that respective correspond same sampling volume. The heavy emission consists mixtur...

UNLABELLED Dopamine transporter (DAT) function is altered by many neurodegenerative diseases. For instance, in Parkinson disease DAT density has been shown to decrease in early disease and to play a role in the occurrence of motor complications. DAT is thus an important imaging target with potential therapeutic relevance in humans and animal models of disease. The PET DAT marker (11)C-methylphe...

We report scanning tunneling microscopy observations, which imply that all atoms in a Cu(001) surface move frequently, even at room temperature. Using a low density of embedded indium "tracer" atoms, we visualize the diffusive motion of surface atoms. Surprisingly, the indium atoms seem to make concerted, long jumps. Responsible for this motion is an ultralow density of surface vacancies, diffu...

In this presentation a multilayer perceptron is used to classify coloured tracers. In fluid mechanics a nonintrusive measuring method delivering experimental information with a Lagrangian point of view (i.e. following the flow) would be extremely useful to clarify the origin, birth and development of vortical structures in technical systems. For this purpose Particle-Tracking-Velocimetry (PTV) ...

This paper theoretically describes and experimentally verifies two mechanisms leading to longitudinal dispersion of a passive tracer in a random array of circular cylinders. We focus on moderate Reynolds numbers of order 10–1000, specifically the range characterized by unsteady cylinder wakes. In this regime, two mechanisms contribute to dispersion, each associated with a distinct region of the...

Understanding the hydrodynamics of three-phase stirred tanks, such as froth flotation cells, is paramount for characterisation turbulence, stability and performance. Although positron emission particle tracking (PEPT) known its effectiveness in measuring particles opaque, high solid content systems, it has not been widely used characterising liquid phase. This work presents a new, neutrally buo...

This research describes the goals, design and implementation of a quasi natural gradient, laboratory scale, sand tank (aquifer) model experiment. The model was used to study the transport of an inorganic tracer (Chloride) in groundwater, within a tropical aquifer (porous medium) material. Three-dimensional sand tank (1.8 m × 0.3 m × 0.8 m) experiments were conducted to investigate contaminant t...

This paper motivates, develops and reviews elementary models for turbulent tracers with a background mean gradient which, despite their simplicity, have complex statistical features mimicking crucial aspects of laboratory experiments and atmospheric observations. These statistical features include exact formulas for tracer eddy diffusivity which is non-local in space and time, exact formulas an...