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Later systems have used modern electronic controls and quickly reversible motors with good slow-speed control to the hoist winch motors, so as to give a positioning accuracy of inches. Some early systems used controllable hydraulic gearboxes to achieve the same result, but these added complexity and cost and so were only popular where high ...
A simplified version of the Rabi method consists of a beam of atoms, all having the same speed and the same direction, sent through one interaction zone of length .The atoms are two-level atoms with a transition energy of (this is defined by applying a field ‖ in an excitation direction ^, and thus = | ‖ |, the Larmor frequency), and with an interaction time of = / in the interaction zone.
A steam donkey or donkey engine is a steam-powered winch once widely used in logging, mining, maritime, and other industrial applications. Steam-powered donkeys were commonly found on large metal-hulled multi-masted cargo vessels in the later decades of the Age of Sail on through the Age of Steam, particularly heavily sailed skeleton-crewed ...
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. 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, Diagram 3a. This is an example of the Luff tackle.
The winch is either controlled with a detachable cable, a button inside the car or wireless remote. Older vehicles may have a PTO winch, controlled via the car's transmission, a secondary clutch maybe used so the vehicle does not need to be moving while winching. Some winches are powered by the pressure generated in the hydraulic steering system.
The 800 series was replaced with the 8000 series by 1978, which offered more powerful engine configurations and an improved hydraulic lift option, yet retained the eight-speed transaxle. Many of the parts for the 800 and 8000 series designs, excepting the engine, are the same or compatible, and are readily available as new and used parts online ...
Vitruvius, a military engineer writing about 28 BC, defined a machine as "a combination of timber fastened together, chiefly efficacious in moving great weights."About a century later, Hero of Alexandria summarized the practice of his day by naming the "five simple machines" for "moving a given weight by a given force" as the lever, windlass, screw for power, wedge, and tackle block (pulley).
In 1930, in a paper entitled 'On a Problem of Formal Logic,' Frank P. Ramsey proved a very general theorem (now known as Ramsey's theorem) of which this theorem is a simple case. This theorem of Ramsey forms the foundation of the area known as Ramsey theory in combinatorics .