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American wire gauge. American Wire Gauge (AWG) is a logarithmic stepped standardized wire gauge system used since 1857, predominantly in North America, for the diameters of round, solid, nonferrous, electrically conducting wire. Dimensions of the wires are given in ASTM standard B 258. [1] The cross-sectional area of each gauge is an important ...
The recent formula used by the Brannock device assumes a foot length of 2 barleycorns less than the length of the last; thus, men's size 1 is equivalent to a last's length of 8 + 1 ⁄ 3 in (21.17 cm) and foot's length of 7 + 2 ⁄ 3 in (19.47 cm), and children's size 1 is equivalent to 4 + 1 ⁄ 4 in (10.8 cm) last's length and 3 + 7 ⁄ 12 in ...
Snellen chart. Purpose. Snellen chart is used to estimate visual acuity (last three rows are 20/15, 20/13 and 20/10) A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen who developed the chart in 1862 as a measurement tool for the acuity formula ...
Grade (slope) The grade (US) or gradient (UK) (also called stepth, slope, incline, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a special case of the slope, where zero indicates horizontality. A larger number indicates higher or steeper ...
It is defined as the pressure exerted by a column of water of 1 inch in height at defined conditions. At a temperature of 4 °C (39.2 °F) pure water has its highest density (1000 kg/m 3). At that temperature and assuming the standard acceleration of gravity, 1 inAq is approximately 249.082 pascals (0.0361263 psi). [2]
For 6/6 = 1.0 acuity, the size of a letter on the Snellen chart or Landolt C chart is a visual angle of 5 arc minutes (1 arc min = 1/60 of a degree), which is a 43 point font at 20 feet. [10] By the design of a typical optotype (like a Snellen E or a Landolt C), the critical gap that needs to be resolved is 1/5 this value, i.e., 1 arc min.
The wheel size is the size designation of a wheel given by its diameter, width, and offset. The diameter of the wheel is the diameter of the cylindrical surface on which the tire bead rides. The width is the inside distance between the bead seat faces. The offset is the distance from the wheel's true centerline (half the width) to the wheel's ...
Nominal Pipe Size (NPS) is a North American set of standard sizes for pipes used for high or low pressures and temperatures. [1] " Nominal" refers to pipe in non-specific terms and identifies the diameter of the hole with a non-dimensional number (for example – 2-inch nominal steel pipe" consists of many varieties of steel pipe with the only criterion being a 2.375-inch (60.3 mm) outside ...