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A diffusion tube consists of a small, hollow, usually transparent, acrylic or polypropylene plastic tube, roughly 70mm long, with a cap at each end. One of the caps (coloured white) is either completely removed to activate the tube (in the case of nitrogen dioxide sampling) or contains a filter allowing in just the gas being studied.
In chemical engineering, a Stefan tube is a device that was devised by Josef Stefan in 1874. [1] It is often used for measuring diffusion coefficients . [ 1 ] [ 2 ] It comprises a vertical tube, over the top of which a gas flows and at the bottom of which is a pool of volatile liquid that is maintained in a constant-temperature bath.
Dialysis tubing. Dialysis tubing, also known as Visking tubing, is an artificial semi-permeable membrane tubing [1] used in separation techniques, that facilitates the flow of tiny molecules in solution based on differential diffusion.
Fick's experiments (modeled on Graham's) dealt with measuring the concentrations and fluxes of salt, diffusing between two reservoirs through tubes of water. It is notable that Fick's work primarily concerned diffusion in fluids, because at the time, diffusion in solids was not considered generally possible. [3]
Crookes X-ray tube from around 1910 Another Crookes x-ray tube. The device attached to the neck of the tube (right) is an "osmotic softener". When the voltage applied to a Crookes tube is high enough, around 5,000 volts or greater, [16] it can accelerate the electrons to a high enough velocity to create X-rays when they hit the anode or the glass wall of the tube.
Dialysis is the process used to change the matrix of molecules in a sample by differentiating molecules by the classification of size. [6] [7] It relies on diffusion, which is the random, thermal movement of molecules in solution (Brownian motion) that leads to the net movement of molecules from an area of higher concentration to a lower concentration until equilibrium is reached.
The electrons in these tubes moved in a slow diffusion process, never gaining much speed, so these tubes didn't produce cathode rays. Instead, they produced a colorful glow discharge (as in a modern neon light ), caused when the electrons struck gas atoms, exciting their orbital electrons to higher energy levels.
A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. [2] The images may represent electrical waveforms on an oscilloscope , a frame of video on an analog television set (TV), digital raster graphics on a computer monitor , or ...