Abstract: A method of measuring a flow rate of a fluid flowing along a path, the method comprising: transmitting successive pairs of periodic signals through the fluid, the respective signals of each pair being transmitted in opposite directions along, and from opposite ends of, the path; determining a difference in propagation times of each signal of each pair along the path; and determining a flow rate of fluid along the path based on the difference in propagation times of the signals of each pair along the path; wherein a phase of each signal is altered with respect to a phase of at least one other signal transmitted along the path.

Abstract: A method of measuring a flow rate of a fluid flowing along a path, the method comprising: transmitting successive pairs of periodic signals through the fluid, the respective signals of each pair being transmitted in opposite directions along, and from opposite ends of, the path; determining a difference in propagation times of each signal of each pair along the path; and determining a flow rate of fluid along the path based on the difference in propagation times of the signals of each pair along the path; wherein a phase of each signal is altered with respect to a phase of at least one other signal transmitted along the path.

Abstract: A device that provides a display indicating an absence of power to an LCD is disclosed. The device includes a continuous polarizing filter layer disposed within a display area that makes up a portion of the total display area of the LCD. A layer of liquid crystals is disposed between alignment gratings and optically coupled to the continuous polarizing filter layer. A discontinuous polarizing filter layer is optically coupled to the layer of liquid crystals. The discontinuous polarizing filter layer has a plane of polarization aligned with the plane of polarization of the continuous polarizing filter, and the discontinuous polarizing filter layer comprises a contour within the display area conforming to an image, so that the image is displayed in the absence of an electric field and indicates an absence of power.