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Wuerker, R. F.

Publications and source records attributed to Wuerker, R. F..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Recording fluid currents by holography

Convection in fluids can be studied with aid of holographic apparatus that reveals three-dimensional motion of liquid. Apparatus eliminates images of fixed particles such as dust on windows and lenses, which might mask behavior of moving fluid particles. Holographic apparatus was developed for experiments on fluid convection cells under zero gravity. Principle is adaptable to study of fluid processes-for example, electrochemical plating and combustion in automotive engines.

Heflinger, L. O.↗
NASA NTRS1980

Holography on the NASA Space Shuttle

The SL-3 flight on the Space Shuttle will carry a 25 mW He-Ne laser holographic recorder for recording the solution growth of triglycine sulfate (TGS) crystals under low-zero gravity conditions. Three hundred holograms (two orthogonal views) will be taken (on SO-253 film) of each growth experiment. Processing and analysis (i.e., reconstructed imagery, holographic schlieren, reverse reference beam microscopy, and stored beam interferometry) of the holographic records will be done at NASA/MSFC. Other uses of the recorder on the Shuttle have been proposed.

Wuerker, R. F.↗
NASA NTRS1977

Spatial filter for Q-switched lasers

A spatial filtered Q-switched laser system is reported that prevents ionization of air in close proximity to the aperture of the spatial filter. A compound lens system having an astigmatic focus is positioned between the laser and the spatial filter for defocusing the light beam emanating from the laser in the vicinity of the aperture of the spatial filter to an intensity below that which produces ionization of air. The preferred construction of the compound lens system as viewed from the laser comprises a cylindrical lens and a pair of positive lenses.

Wuerker, R. F.↗
NASA NTRS1977

Spatial filter for Q-switched laser

Set of compound lenses reduces ionization and sparks that frequently occur around pinhole aperture in spatial filter. Lens system produces astigmatic focus near pinhole, reducing energy level there below ionization theshold.

Heflinger, L. O.↗
NASA NTRS1977

Dual-purpose holocamera

Camera utilizes same basic structure to record bright-field holograms (single and double exposure interferograms) or, with minor adjustments, record forward scattered light holograms. Components that must be interchanged to convert camera can be mounted on sliding plate.

Heflinger, L. O.↗
NASA NTRS1976

Particle and flow field measurements by laser holography

Holograms make transmission recordings of aerodynamic events which are real-illuminated with ground-glass light diffusers and with no requirements for precision. The three-dimensional interferograms can be recorded by stored-beam, double-exposure, and double-plate techniques. Weak traveling shock waves, generated by rotating blade rows of an aircraft fan compressor, can be visualized by rapid double-exposure holograms recorded with a ruby laser. The same laser technique can also determine flow velocities from holograms of small flow-entrained particles. Particles larger than one-quarter millimeter are recorded under rear diffuse illumination conditions. Smaller particles can be recorded by their own forward scattering of laser light through the sensitivity of the holographic process for weak signals. Since the holographic apparatus can be path-matched, both particle and flow interferograms can be recorded with lasers of short coherence length.

Wuerker, R. F.↗
NASA NTRS1974

Application of holography to flow visualization within rotating compressor blade row

Two holographic interblade row flow visualization systems were designed to determine the three-dimensional shock patterns and velocity distributions within the rotating blade row of a transonic fan rotor, utilizing the techniques of pulsed laser transmission holography. Both single- and double-exposure bright field holograms and dark field scattered-light holograms were successfully recorded. Two plastic windows were installed in the rotor tip casing and outer casing forward of the rotor to view the rotor blade passage. The viewing angle allowed detailed investigation of the leading edge shocks and shocks in the midspan damper area; limited details of the trailing edge shocks also were visible. A technique was devised for interpreting the reconstructed holograms by constructing three dimensional models that allowed identification of the major shock systems. The models compared favorably with theoretical predictions and results of the overall and blade element data. Most of the holograms were made using the rapid double-pulse technique.

Wuerker, R. F.↗
NASA NTRS1972

Holographic interferometry.

Review of the techniques and applications of holographic interferometry. The recording of a 'reflected-light' hologram with a gas laser is described in order to illustrate the unique optical properties of a hologram. Special types of interferometric measurement, such as stored-beam holographic interferometry and double-exposure holographic interferometry, are then discussed. Applications of gas-laser holographic interferometry to the detection of internal flaws in steel tubing are cited, as well as applications involving the testing of aircraft and automotive tires and aircraft honeycomb composites for bond integrity and the prediction of failure in mechanical components. Finally, applications of the pulsed solid-state ruby laser in holographic interferometry are considered.

Wuerker, R. F.↗
NASA NTRS1971

Multifrequency laser beams for holographic contouring

Pulsed ruby laser emits two optical frequencies simultaneously so holographic recordings of test object give images showing desired range contours. Process enables generation of contour maps for practical applications such as gaging size and shape of mechanical parts and other structures.

Heflinger, L. O.↗
NASA NTRS1971

Holographic interferometry

Holographic interferometry application to laser NDT of objects with nonoptical surfaces, describing techniques and industrial uses

Wuerker, R. F.↗
NASA NTRS1970

Pulsed laser holography

Pulsed laser holography, discussing illumination source and holocameras for high contrast recording with Q switched ruby lasers

Heflinger, L. O.↗
NASA NTRS1970

Microbalance

A reed is vibrated by the minute vibrations of a base frame which, in turn, is vibrated by a driver mechanism. The vibration of the reed is picked off and fed back to the driver means, causing the base frame to be vibrated at the resonant frequency of the reed. A counter is connected to the feedback loop to measure the frequency of the reed oscillations. By adding the mass to be weighed to the reed, the resonant frequency of the reed will be changed, which will in turn change the reading at the counter by an amount which is proportional to the added mass.

Heflinger, L. O.↗
NASA NTRS1970

Pulsed laser holography

High speed pulsed ruby laser holography, discussing transmission-reflection holocameras and applications

Heflinger, L. O.↗