Ul

ULF
Abbreviation of Ultra Low Frequency.
Ullage
The amount that a container, such as a fuel tank, lacks of being full.
Ullage Rocket
A small rocket used in space to impart an acceleration to a tank system to insure that the liquid propellants collect in the tank in such a manner as to flow properly into the pumps or thrust chamber.
ULSI
Abbreviation of Ultra Large Scale Integration.
Ultimate Elongation
Alternate term for elongation of material at rupture under tensile loading.
Ultimate Load
The absolute maximum magnitude of load which a structure can sustain, limited only by ultimate failure.
Ultimate Strength
Maximum stress at point of rupture.
Ultimate Vacuum
The limiting pressure approached in a vacuum system after sufficient pumping time to establish that further reductions in pressure will be negligible.
Ultra High Frequency
Radio frequencies that are between 300 to 3000 MHz.
Ultra Large Scale Integration
A chip with over 1,000,000 components.
Ultra Low Frequency
The portion of the electromagnetic spectrum below 3 Hz.
Ultrafine Particles
EPA classification of particles having aerodynamic diameters less than or equal to 0.1 micrometer.
Ultramarine
A blue pigment derived from lapis lazuli.
Ultrasonic
Sound at frequencies above the audible range, i.e. above about 20 kHz.
Ultrasonic Cleaning
An effective cleaning process for small items and fine detail where the item is immersed in a bath of cleaning fluid that is excited at ultrasonic frequenices.
Ultrasonic Machining
Material-removal operation in which an abrasive slurry flows between a tool, vibrating at a high frequency, and a workpiece.
Ultrasonic Testing
A method of non destructive testing of steel bars, plates or parts with high frequency sound waves produced with electronic equipment.
Ultraviolet Catastrophe
A shortcoming of the Rayleigh-Jeans formula, which attempted to describe the radiancy of a blackbody at various frequencies of the electromagnetic spectrum.
Ultraviolet Light
Electromagnetic radiation with wavelength longer than that of x-rays but shorter than that of visible light.