Search results
Results from the WOW.Com Content Network
Utility frequency. The waveform of 230 V and 50 Hz compared with 120 V and 60 Hz. The utility frequency, (power) line frequency ( American English) or mains frequency ( British English) is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user.
After accumulating, for example, 70 hours of driving and on-duty time within a period of 8 days, a driver's daily driving limit may be reduced (70 / 8 = 8.75 driving hours per day). A driver may be allowed (but not required) to take 34 hours off-duty to reset the weekly total back to zero (also known as a "34-hour restart").
Sikorsky MH-60 Jayhawk Mitsubishi SH-60 Piasecki X-49. The Sikorsky SH-60/MH-60 Seahawk (or Sea Hawk) is a twin turboshaft engine, multi-mission United States Navy helicopter based on the United States Army UH-60 Black Hawk and a member of the Sikorsky S-70 family. The most significant modifications are the folding main rotor blades and a ...
The Sikorsky UH-60 Black Hawk is a four-blade, twin-engine, medium-lift utility military helicopter manufactured by Sikorsky Aircraft. Sikorsky submitted the S-70 design for the United States Army 's Utility Tactical Transport Aircraft System (UTTAS) competition in 1972. The Army designated the prototype as the YUH-60A and selected the Black ...
For a given sampling rate ( samples per second ), the Nyquist frequency ( cycles per second) is the frequency whose cycle-length (or period) is twice the interval between samples, thus 0.5 cycle/sample. For example, audio CDs have a sampling rate of 44100 samples/second. At 0.5 cycle/sample, the corresponding Nyquist frequency is 22050 cycles ...
The railway signalling system used across the majority of the United Kingdom rail network uses lineside signals to control the movement and speed of trains. The modern-day system mostly uses two, three, and four aspect colour-light signals using track circuit – or axle counter – block signalling. [1] [2] It is a development of the original ...
Design and development Origin In the early 1930s, Rolls-Royce started planning its future aero-engine development programme and realised there was a need for an engine larger than their 21-litre (1,296 cu in) Kestrel, which was being used with great success in a number of 1930s aircraft. Consequently, work was started on a new 1,100 hp (820 kW)-class design known as the PV-12, with PV standing ...
A 4-drum delayed coking unit in a petroleum refinery. A delayed coker is a type of coker whose process consists of heating a residual oil feed to its thermal cracking temperature in a furnace with multiple parallel passes. This cracks the heavy, long chain hydrocarbon molecules of the residual oil into coker gas oil and petroleum coke. [1] [2] [3]