When the rays of the sun or a candle, or dark radiation from a warm body, are incident on the vanes, the dark side of each vane is repelled more than the bright side, and thus the vanes are set into rotation with accelerated speed, which becomes uniform when the forces produced by the radiation are balanced by the friction of the pivot and of the residual air in the globe.
The nearly vertical vanes is balanced by the convection currents.
Centrifugal pumps, constructed with several stages or sets of vanes, and suitable for high lifts, have been introduced for mine service.
The best-known of Joule's experiments was that in which a brass paddle consisting of eight arms rotated in a cylindrical vessel of water containing four fixed vanes, which allowed the passage of the arms of the paddle but prevented the water from rotating as a whole.
The style of cultivation vanes according to the)43 209,942 266,982 nature of the ground, terraces sup ~52 14,709 11,910 ported by stone walls being much;83 173,537 322,627 used in mountainous districts.
In length, actuating a universal joint on the first spindle of the register; it consisted of an air-tight thin metal tube with a coned fore-end, carrying flat metal vanes set at an angle.
The typical mine fan consists of a shaft upon which are mounted a number of vanes enclosed in a casing; the air entering a central side inlet is caught up by the revolving vanes and thrown out at the periphery by the centrifugal force thus generated.
Was whether the mechanical impulsion was a direct effect of the light, or whether the radiation only set up internal stresses, acting in and through the residual air, between the vanes and the walls of the enclosure.
If the light exerted direct impulsion on the vanes, their motion would gradually drag the case round after them, by reason of the friction of the residual air in the bulb and of the pivot.
On the other hand, if the effects arose from balanced stresses set up inside the globe by the radiation, the effects on the vanes and on the case would be of the nature of action and reaction, so that the establishment of motion of the vanes in one direction would involve impulsion of the case in the opposite direction; but when the motion became steady there would no longer be any torque either on the vanes or on the case, and the latter would therefore come back to its previous position of equilibrium; finally, when the light was turned off, the decay of the motion of the vanes would involve impulsion of the case in the direction of their motion until the moment of the restoring torque arising from the suspension of the case had absorbed the angular momentum in the system.
The important part played by the residual air in the globe had also been deduced by Osborne Reynolds from observing that on turning off the light, the vanes came to rest very much sooner than the friction of the pivot alone would account for; in fact, the rapid subsidence is an illustration of Maxwell's great theoretical discovery that viscosity in a gas (as also diffusion both of heat and of the gas itself) is sensibly independent of the density.
He lays stress on the dimensional relations of the problem, pointing out that the phenomena which occur with large vanes in highly rarefied gas could also occur with proportionally smaller vanes in gas at higher pressure.
Hull; some months earlier Lebedew had published in the Annalen der Physik a verification for metallic vanes so thin as to avoid the gasaction, by preventing the production of sensible difference of temperature between the two faces by the incident radiation.
Lebedew in 1900 succeeded, by operating on metallic vanes so thin that the exposed and averted faces were practically at the same temperature, in satisfactorily verifying the relation for metals; and very soon after, E.
Body of Grenade Sleeve with Vanes Regulating Pin 'FIG.15 ' 8peoial Cartridge Discharger Barrel Attachment the spring of 1878.
Each channel is divided into a series of pockets by equally spaced vanes inclined at 45°.
The air-ways k, k, in the fixed vanes establish communication between the cores of the vortices and the atmosphere.
The remiges and rectrices indicate perfect feathers, with shaft and complete vanes which were so neatly finished that they must have possessed typical radii and hooklets.
That velocity would be gradually destroyed by the resistance of the air to the forward flight; it was, therefore, the office of the steamengine and the vanes it actuated simply to repair the loss of velocity; it was made, therefore, only of the power a,nd weight necessary for that small effect."