A gauge for monitoring the relative height of two points comprises a generally tubular conduit extending from a first end thereof via a first limb thereof to a monitoring position spaced from the first end and via a second limb of the conduit from the monitoring position to a second end of the conduit in the region of its first end, two immiscible fluids of different densities, each in one of the first and second limbs with a mutual interface within the region of the monitoring position, means t...

A method and apparatus for measuring the relative density of a gas, for example natural gas. The gas is supplied through an inlet to a chamber and is output through an outlet. Using a control and an ultra-sonic transducer emitter and an ultra-sonic transducer receiver, the speed of sound in the gas corrected to standard conditions is calculated. Then, the control operates to measure the relative density RD of the gas using the formula where SoSsc is the speed of sound in the gas corrected to sta...

A humidity measurement process and humidity measurement scale are derived from the physics of relative humidity. Absolute moisture content is determined independent of any measurement or knowledge of the source temperature. The humidity measurement is equivalent to the volumetric fraction of water vapor in the measured gas mixture, expressed as a percentage in a fixed range from 0 to 100%. The operating principles of the measurement process and measurement scale are described for use with an ins...

A relative humidity sensor includes a printed circuit board having a central passageway therethrough and a dielectric film extending across the passageway with electrodes mounted on that portion of the film in the passageway so as to generate a capacitance which will vary directly with the amount of moisture content in the film.

A relative velocity sensing device for sensing an optical beam spot, for example, by using a tracking error difference signal that fluctuates as a sine-wave in accordance with a movement of the beam spot. The tracking error difference signal is converted into a first sawtooth wave signal, and a second sawtooth wave signal, having a phase which is offset from the first sawtooth wave signal by one half of the period thereof. A first differential signal is obtained in accordance with the first sawt...

An obliterating machine can be operated by means of a card, made of synthetic plastic material, that features longitudinal grooves and a toothing and that can be inserted in a receiving seat delimited by a pair of plates mounted within the machine and forming a profile complementar to the profile of the card. A couple of feeler pins, associated with respective micro-switches, are movable along directions perpendicular and parallel to the seat, and are designed to detect the presence of the card ...

A humidity measurement process and humidity measurement scale are derived from the physics of relative humidity. Absolute moisture content is determined independent of any measurement or knowledge of the source temperature. The humidity measurement is equivalent to the volumetric fraction of water vapor in the measured gas mixture, expressed as a percentage in a fixed range from 0 to 100%. The operating principles of the measurement process and measurement scale are described for use with an ins...

A relative pressure measuring instrument has a reference pressure feed that offers a high measure of safety and is easy to produce. Included is a relative pressure measuring cell having a pressure sensitive element, on whose process-facing side there is present during operation a pressure (p) to be measured, on whose process-averted side there is present during operation a reference pressure (p.sub.R) to which the pressure (p) to be measured is to be referred, a support on which the relative pre...

A driven element (100) has a first sheave (13) and a second moveable sheave (9). The sheaves (9 and 13) are rotatably tied together so that there is no relative motion between the two sheaves (9 and 13).

A method and a system for measuring a relative position and orientation of range cameras using a movement of an object within a scene. In general, the present invention determines the relative pose between two cameras by measuring a path the movement of the object makes within a scene and calculating transformation parameters based on these measurements. These transformation parameters are used to determine the relative position of each camera with respect to a base camera. In a preferred embodi...