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Flooring is the general term for a permanent covering of a floor, or for the work of installing such a floor covering. Floor covering is a term to generically describe any finish material applied over a floor structure to provide a walking surface. Both terms are used interchangeably but floor covering refers more to loose-laid materials.
The board foot or board-foot is a unit of measurement for the volume of lumber in the United States and Canada [1]. It equals the volume of a board that is one foot (30.5 cm) in length, one foot in width, and one inch (2.54 cm) in thickness, or exactly 2.359 737 216 liters .
The first, a 665 foot (203 m) half-wave mast was installed at radio station WABC's 50 kW transmitter at Wayne, New Jersey in 1931. [ 4 ] [ 5 ] During the 1930s it was found that the diamond shape of the Blaw-Knox tower had an unfavorable current distribution which increased the power emitted at high angles, causing multipath fading in the ...
An adult human foot is about 28 cm (11 in) long. The decimetre ( SI symbol: dm ) is a unit of length in the metric system equal to 10 −1 metres ( 1 / 10 m = 0.1 m ). To help compare different orders of magnitude , this section lists lengths between 10 centimeters and 100 centimeters (10 −1 meter and 1 meter).
The operating principle of a parabolic antenna is that a point source of radio waves at the focal point in front of a paraboloidal reflector of conductive material will be reflected into a collimated plane wave beam along the axis of the reflector.
The lux (symbol: lx) is the unit of illuminance, or luminous flux per unit area, in the International System of Units (SI). [1] [2] It is equal to one lumen per square metre.In photometry, this is used as a measure of the irradiance, as perceived by the spectrally unequally responding human eye, of light that hits or passes through a surface.
Coaxial cable, or coax (pronounced / ˈ k oʊ. æ k s /), is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric (insulating material); many coaxial cables also have a protective outer sheath or jacket.
German physicist Heinrich Hertz first demonstrated the existence of radio waves in 1887 using what we now know as a dipole antenna (with capacitative end-loading). On the other hand, Guglielmo Marconi empirically found that he could just ground the transmitter (or one side of a transmission line, if used) dispensing with one half of the antenna, thus realizing the vertical or monopole antenna.