For example, when the desired reference axis is the x-axis, the second moment of area I _ { xx } ( often denoted as I _ x ) can be computed in Cartesian coordinates as
2.
The reference axis are the " cardo " ( north south, via Madonna and via Garibaldi ) and the " Decumano " ( east west, via Matteotti and via Porta Ronca ).
3.
:Ray, EPLLA means the area of the effective light-emitting surface of a lamp, measured by determining the area of the 2-dimensional graphic representation of the lamp's lit lens area on a plane perpendicular to the lamp's reference axis and touching the most exterior point of the lens . " Reference axis " means the H V axis used for photometric requirements, " i . e . ", the effective centre of the lamp's beam pattern as produced at the lamp.
4.
:Ray, EPLLA means the area of the effective light-emitting surface of a lamp, measured by determining the area of the 2-dimensional graphic representation of the lamp's lit lens area on a plane perpendicular to the lamp's reference axis and touching the most exterior point of the lens . " Reference axis " means the H V axis used for photometric requirements, " i . e . ", the effective centre of the lamp's beam pattern as produced at the lamp.
5.
:To simplify this and bring it into the realm of practical application outside of a compliance laboratory setting : The reference axis of most automotive and motorcycle lighting devices is reasonably easy to determine; it is " straight back " from the device " with the device oriented in space exactly as it is oriented when installed on the vehicle " . if you will place a sheet of fine-grid graph paper such that it forms a vertical plane at 90?to the lamp's reference axis, move the paper such that it just barely touches whatever part ( s ) of the lens protrude closest to the paper, illuminate the lamp, trace the blob ( s ) of light on the side of the paper opposite the lamp, and then calculate the area enclosed by your trace, you will have a close enough approximation of the device's EPLLA for most purposes.
6.
:To simplify this and bring it into the realm of practical application outside of a compliance laboratory setting : The reference axis of most automotive and motorcycle lighting devices is reasonably easy to determine; it is " straight back " from the device " with the device oriented in space exactly as it is oriented when installed on the vehicle " . if you will place a sheet of fine-grid graph paper such that it forms a vertical plane at 90?to the lamp's reference axis, move the paper such that it just barely touches whatever part ( s ) of the lens protrude closest to the paper, illuminate the lamp, trace the blob ( s ) of light on the side of the paper opposite the lamp, and then calculate the area enclosed by your trace, you will have a close enough approximation of the device's EPLLA for most purposes.
मोबाइल