8,044 research outputs found
Composite mobile system for holographic nondestructive testing
Innovation provides a single system flexible enough to test objects ranging from large amplitude displacement and/or velocities down to extremely small displacements and/or velocities by making only a few minor adjustments in the component arrangements
Photography of random motion with a holographic camera
Three-dimensional system uses two additional mirrors and path compensators. It is essentially three mutually-orthogonal one-dimensional systems with common focus. Laser beam is split into four parts, three of which are object beams; and fourth is reference beam. Size of each ellipse depends on magnitude of velocity vectors
Holographic system for nondestructive testing
A description is given of a holographic system for nondestructive testing. The system is comprised of a mirror which illuminates the test object surface; the mirror is positionable to direct illumination on an object at varying angles with respect to a line normal to the surface of the object. In this manner holograms may be produced with varying degrees of sensitivity enabling optimum observation of dimensions of deformation of an object occurring between test exposures
Hybrid holographic non-destructive test system
An automatic hybrid holographic non-destructive testing (HNDT) method and system capable of detecting flaws or debonds contained within certain materials are described. This system incorporates the techniques of optical holography, acoustical/optical holography and holographic correlation in determining the structural integrity of a test object. An automatic processing system including a detector and automatic data processor is used in conjunction with the three holographic techniques for correlating and interpreting the information supplied by the non-destructive systems. The automatic system also includes a sensor which directly translates an optical data format produced by the holographic techniques into electrical signals and then transmits this information to a digital computer for indicating the structural properties of the test object. The computer interprets the data gathered and determines whether further testing is necessary as well as the format of this new testing procedure
Coherence-length extender
Holograms of large objects may be formed by using several coherent low-intensity laser sources. If several low intensity laser sources are available, they can be applied simultaneously. Each source is then used to establish one object beam and one reference beam whose path lengths are equal, recording a small portion of the total object
Real time moving scene holographic camera system
A holographic motion picture camera system producing resolution of front surface detail is described. The system utilizes a beam of coherent light and means for dividing the beam into a reference beam for direct transmission to a conventional movie camera and two reflection signal beams for transmission to the movie camera by reflection from the front side of a moving scene. The system is arranged so that critical parts of the system are positioned on the foci of a pair of interrelated, mathematically derived ellipses. The camera has the theoretical capability of producing motion picture holograms of projectiles moving at speeds as high as 900,000 cm/sec (about 21,450 mph)
Time-series spectroscopy of the rapidly oscillating Ap star HR 3831
We present time-series spectroscopy of the rapidly oscillating Ap star HR
3831. This star has a dominant pulsation period of 11.7 minutes and a rotation
period of 2.85 days. We have analysed 1400 intermediate-resolution spectra of
the wavelength region 6100--7100 AA obtained over one week, using techniques
similar to those we applied to another roAp star, Alpha Cir.
We confirm that the H-alpha velocity amplitude of HR 3831 is modulated with
rotation phase. Such a modulation was predicted by the oblique pulsator model,
and rules out the spotted pulsator model. However, further analysis of H-alpha
and other lines reveal rotational modulations that cannot easily be explained
using the oblique pulsator model. In particular, the phase of the pulsation as
measured by the width of the H-alpha line varies with height in the line.
The variation of the H-alpha bisector shows a very similar pattern to that
observed in Alpha Cir, which we have previously attributed to a radial node in
the stellar atmosphere. However, the striking similarities between the two
stars despite the much shorter period of Alpha Cir (6.8 min) argues against
this interpretation unless the structure of the atmosphere is somewhat
different between the two stars. Alternatively, the bisector variation is a
signature of the degree l of the mode and not the overtone value n.
High-resolution studies of the metal lines in roAp stars are needed to
understand fully the form of the pulsation in the atmosphere.Comment: 13 pages, 20 figures, accepted by MNRA
Hybrid holographic system using reflected and transmitted object beams simultaneously Patent
Hybrid holographic system using reference, transmitted, and reflected beams simultaneousl
Hybrid holographic system
Improved holographic system has high degree of resolution and capability of providing a hologram of a moving object without requiring that the system have a high mechanical stability
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