Apparatus for measuring an aircraft's speed and height

An apparatus for measuring aircraft horizontal speed and height above ground without the need for airborne cooperative devices is presented. Two ground level TV cameras separated by a measured distance and pointed at zenith are placed in line with the projection of the expected path of the aircraft. Speed is determined by measuring the time that it takes the aircraft to travel between the fields of view of the two TV cameras using zenith crossings as the reference points. Height is determined by correlating the speed with the time required to cross the field of view of either of the two cameras

Preparation of highly fluorinated diols containing ether linkages.

Hydroxy-terminated perfluoroethers and polyurethane resins derived from ethers have outstanding chemical resistance and good thermal properties. They can be used as potting compounds, coatings, and seals. The hydroxy-terminated ethers serve as intermediates in the synthesis of highly fluorinated elastomers and adhesives

Highly fluorinated polyurethanes

The reaction perfluorinated hydroxyl terminated polyether with diisocyanate to form polyurethane is discussed. Data are given on the resin's oxidation stability, chemical resistance, and low temperature flexibility

Preparation of highly fluorinated polyurethanes

New polyurethanes, formed from a reaction of a prepolymer diol and a perfluorinated diisocyanate, are nonflammable and possess high corrosion resistance and good low temperature flexibility. Polymer hardness increases rapidly with increasing ratio of diisocaynate to diol, but its glass transition temperature is not adversely affected

Hydroxy terminated perfluoro ethers Patent

Chemical synthesis of hydroxy terminated perfluoro ethers as intermediates for highly fluorinated polyurethane resin

Preparation of perfluoropolyether prepolymers

Fluorinated prepolymers are used to generate highly fluorinated polymers which possess most of the desirable properties of polytetrafluoroethylene, such as nonflammability and high corrosion resistance, while retaining good low temperature flexibility

Soft parton resummation in the current region of semi-inclusive deep inelastic scattering

We discuss resummation of large logarithmic terms that appear in the cross-section of semi-inclusive DIS in the case when the final-state hadron follows the direction of the incoming electroweak vector boson in the c.m. frame of the vector boson and the initial-state proton.Comment: Presented at the 8th International Workshop on Deep Inelastic Scattering (DIS2000), Liverpool, U.K., April 2000; 4 pages, 2 fig

Film advance indicator

A film advancement indicator which includes an optical sensor that detects the rotational movement of a disc that rotates only when the film advance is described. When the film does not advance, an indicator light is activated. A counter is included in the electronic circuit to determine the number of film frames advanced