Abstract: A method of determining a velocity of air flowing in an air flow direction through an opening. The method includes locating first and second transducer assemblies in the opening, to position the first and second transducer assemblies spaced apart by a predetermined distance along a substantially straight line of sight defining a non-zero angle in a horizontal plane between the line of sight and the air flow direction. A controller is operatively connected with the first and second transducer assemblies respectively, via a four-wire interface in which two of the wires are for power transmission and two of the wires are for transmitting signals. The transducer assemblies are time-synchronized. First and second electronic signal pulses are transmitted between the first and second transducer assemblies. Based on the transit times, the non-zero angle, and the predetermined distance, the velocity of the air flowing in the air flow direction is determined.

Abstract: A method of determining a velocity of air flowing in an air flow direction through an opening. The method includes locating first and second transducer assemblies in the opening, to position the first and second transducer assemblies spaced apart by a predetermined distance along a substantially straight line of sight defining a non-zero angle in a horizontal plane between the line of sight and the air flow direction. A controller is operatively connected with the first and second transducer assemblies respectively, via a four-wire interface in which two of the wires are for power transmission and two of the wires are for transmitting signals. The transducer assemblies are time-synchronized. First and second electronic signal pulses are transmitted between the first and second transducer assemblies. Based on the transit times, the non-zero angle, and the predetermined distance, the velocity of the air flowing in the air flow direction is determined.

Abstract: The card is preferably made of cardboard and has two precut elements. The first one has an elongated rectangular base from which projects a representation of a known personage, preferably a showbusiness or sports star, which is printed on one or both sides of the card. The base has two opposite ends in which transverse slots are precut. The second element precut in the card is in the shape of an elongated rectangular band foldable at mid-length, which has two opposite ends in which slots are also precut. The slots of the base and the band are positioned so that, when the first and second elements have been cut and the band has been folded at mid-length, the slots of the band are engageable into the slots of the base of the first element to fix the band to the base and thus forms a triangular support from which the representation of the known personage extends perpendicularly. Positioning of this support on a horizontal surface gives a standing full length portrait of the personage on this horizontal surface.