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The tree provides distributed mechanical support, reducing localised mechanical deflections, which in turn reduces optical distortion. [4] Unlike the applications described above, which are two-dimensional, the whippletrees in telescope mirror support cells are three-dimensional designs, [ 5 ] since the tree must support multiple points over an ...
Early on, it was customary to trim and top a tree making it into a 'spar pole' or 'spar tree' for the purpose of supporting the head blocks but gradually the use of wooden spars gave way over the 20th century to the use of steel spars stood up for the purpose. In any event the spars are supported by a number of guy wires. [1]
Selecting a tree as a spar is a particularly important task, so the strength and importance of the spar came to hold symbolic meaning for early loggers of the West. The use of spar trees in logging is now rare, having been replaced since the 1970s by portable towers, called yarders , which can be erected on logging sites and moved as needed.
Some trees have a second swab valve, the two arranged one on top of the other. The intention is to allow rigging down equipment from the top of the tree with the well flowing while preserving the two-barrier rule. With only a single swab valve, the upper master valve is usually closed to act as the second barrier, forcing the well to be shut in ...
A sail plan is a drawing of a sailing craft, viewed from the side, depicting its sails, the spars that carry them and some of the rigging that supports the rig. [1] By extension, "sail plan" describes the arrangement of sails on a craft. [2] [3] A sailing craft may be waterborne (a ship or boat), an iceboat, or a sail-powered land vehicle.
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Drawing the tree as a node-link diagram thus requires exponential amounts of space to be displayed. One approach is to use a hyperbolic tree, first introduced by Lamping et al. [1] Hyperbolic trees employ hyperbolic space, which intrinsically has "more room" than Euclidean space. For instance, linearly increasing the radius of a circle in ...
Diagram 3 shows three rope parts supporting the load W, which means the tension in the rope is W/3. Thus, the mechanical advantage is three-to-one. Thus, the mechanical advantage is three-to-one. By adding a pulley to the fixed block of a gun tackle the direction of the pulling force is reversed though the mechanical advantage remains the same ...