ULTRA ACCELATOR– Vulcanization is a cross linking process in which individual molecules of rubber (polymer) are converted into a three-dimensional network of interconnected (polymer) chains through chemical cross links (of sulphur). … Both discovered the use of Sulphur and White Lead as a vulcanization system for Natural Rubber.
ULTRAVIOLET LIGHT– Ultraviolet light is a type of electromagnetic radiation that makes black-light posters glow, and is responsible for summer tans — and sunburns. However, too much exposure to UV radiation is damaging to living tissue.
UV radiation is widely used in industrial processes and in medical and dental practices for a variety of purposes, such as killing bacteria, creating fluorescent effects, curing inks and resins, phototherapy and suntanning. Different UV wavelengths and intensities are used for different purposes.
Ultraviolet light is a form of radiation which is not visible to the human eye. It’s in an invisible part of the “electromagnetic spectrum”. Radiated energy, or radiation, is given off by many objects: a light bulb, a crackling fire, and stars are some examples of objects which emit radiation.
Both UVA and UVB rays can cause damage to your skin. Sunburn is a sign of short-term overexposure, while premature aging and skin cancer are side effects of prolonged UV exposure.
Ultimate analysis – Precise determination, by chemical means, of the elements and compounds in coal.
Upcast – The passage from and in a mine through which air passes.
Undercut – To cut below or undermine the coal face by chipping away the coal by pick or mining machine. In some localities the terms “undermine” or “underhole” are used.
Underground mine – Also known as a “deep” mine. Usually located several hundred feet below the earth’s surface, an underground mine’s coal is removed mechanically and transferred by shuttle car or conveyor to the surface.
Underground station – An enlargement of an entry, drift, or level at a shaft at which cages stop to receive and discharge cars, personnel, and material. An underground station is any location where stationary electrical equipment is installed. This includes pump rooms, compressor rooms, hoist rooms, battery-charging rooms, etc.
Unit train – A long train of between 60 and 150 or more hopper cars, carrying only coal between a single mine and destination.
Universal coal cutter – A type of coal cutting machine which is designed to make horizontal cuts in a coal face at any point between the bottom and top or to make shearing cuts at any point between the two ribs of the place. The cutter bar can be twisted to make cuts at any angle to the horizontal or vertical.
Upcast shaft – A shaft through which air leaves the mine.