This invention relates to an airfoil for an aircraft and more. particularly to an airfoil with a design Mach number in the range .7 to 1.0 and having an upper surface designed to delay shock wave induced boundary layer separation until high subsonic Mach numbers well above the critical Mach number are reached. The airfoil has an upper surface shaped to control flow accelerations and pressure distribution over the upper surface and prevents separation of the boundary layer due to shock wave formulation at high subsonic speeds well above the critical Mach number. A highly cambered trailing edge section improves overall airfoil lifting efficiency.

SUPPRESSION OF FLUTTER

NASA Case No. LAR-10682-1

Great Britain, Japan, France,
Canada, West Germany, Italy,
Sweden

Address inquiries to:
Langley Research Center
Attn: Patent Counsel
Mail Code: 456

Langley Station

Hampton, VA 23365
U.S.A.

[Corresponding U.S. Patent-Application Pending]

An active aerodynamic control system is described for controlling flutter over a large range of oscillatory frequencies unaffected by mass, stiffness, elastic axis, or center of gravity location of the system, mode of vibration, or subsonic Mach number. It consists of one or more pairs of leading edge and trailing edge, hinged or deformable control surfaces, each pair operated in concert by a stability augmentation system. Torsion and bending motions or deflections of the fluttering member are sensed and converted by the stability augmentation system into leading and trailing edge control surface deflections which produce lift forces and pitching moments to suppress flutter.

This invention is an Optical Radiation Frequency Converter employing metal vapor which is useful in the ultraviolet region of the spectrum. The invention comprises a cell for retaining the metal vapor or gas which is surrounded by an oven. Monochromatic radiation passes through windows in the cell and oven. In the preferred embodiment, the metal vapor for accomplishing third harmonics is one which has its fundamental harmonic frequencies resonance in the spectral region between the fundamental frequencies and the third harmonic. The metal vapor must have a suitable refractive index to provide for phase matching.

The invention illustrates and describes a method and apparatus for eliminating the noise and debris of explosive welding techniques. This is accomplished by placing the explosive in a complete enclosure so that both the sound and debris of the explosion are contained in the enclosure. The welding is accomplished by the explosive pressure applied through the wall of the enclosure to the pieces to be joined.

The novelty of the invention is in eliminating the safety hazards and detrimental psychological effects of the loud noises and scattering of debris which result from use of unconfined explosive welding while maintaining the inherent simplicity of the technique.

BACTERIAL ADENOSINE TRIPHOSPHATE AS A
MEASURE OF URINARY TRACT INFECTION

NASA Case No. GSC-11092-2

Great Britain, France, Canada,
West Germany, Italy, Japan

Address inquiries to:

Goddard Space Flight Center
Attn: Patent Counsel

Mail Code: 204

Greenbelt, MD 20771
U.S.A.

[Corresponding U.S. Patent-Application Pending]

A method is provided for determining bacterial levels in urine samples, which method depends on the quantitative determination of bacterial adenosine triphosphate (ATP) in the presence of non-bacterial adenosine triphosphate. After the removal of nonbacterial ATP, the bacterial ATP is released by cell rupture and is measured by an enzymatic bioluminescent assay using an enzyme obtained from the firefly.