Investigation of the rupture of a plexiglas plate by means of an optical method involving high-speed filming of the shadows originating around holes drilled in the plate

1966 ◽  
Vol 2 (4) ◽  
Author(s):  
Peter Manogg
Keyword(s):  
Optical Method ◽  
High Speed ◽  
Plexiglas Plate

scholarly journals An optical method for measuring exhaust gas pressure from an internal combustion engine at high speed

2017 ◽  
Vol 88 (12) ◽  
pp. 125004 ◽  
Author(s):  
Felix C. P. Leach ◽  
Martin H. Davy ◽  
Dmitrij Siskin ◽  
Ralf Pechstedt ◽  
David Richardson
Keyword(s):  
Internal Combustion Engine ◽  
Optical Method ◽  
High Speed ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Gas Pressure ◽  
Exhaust Gas

Optical Measurements of Unducted Fan Flutter

1993 ◽  
Vol 115 (1) ◽  
pp. 189-196 ◽  
Author(s):  
A. P. Kurkov ◽  
O. Mehmed
Keyword(s):  
Wind Tunnel ◽  
Mode Shape ◽  
Optical Method ◽  
High Speed ◽  
Nonlinear Vibrations ◽  
Optical Measurements ◽  
Optical Data ◽  
Strain Gages ◽  
Trailing Edge ◽  
Blade Tip

The paper describes a nonintrusive optical method for measuring flutter vibrations in unducted fan or propeller rotors and provides detailed spectral results for two flutter modes of a scaled unducted fan. The measurements were obtained in a high-speed wind tunnel. A single-rotor and a dual-rotor counterrotating configuration of the model were tested; however, only the forward rotor of the counterrotating configuration fluttered. Conventional strain gages were used to obtain flutter frequency; optical data provided complete phase results and an indication of the flutter mode shape through the ratio of the leading- to trailing-edge flutter amplitudes near the blade tip. In the transonic regime the flutter exhibited some features that are usually associated with nonlinear vibrations. Experimental mode shape and frequencies were compared with calculated values that included centrifugal effects.

scholarly journals Experimental visualization of aerodynamic sound sources using parallel phase-shifting interferometry

2020 ◽  
Vol 61 (9) ◽  
Author(s):  
Risako Tanigawa ◽  
Kohei Yatabe ◽  
Yasuhiro Oikawa
Keyword(s):  
Optical Method ◽  
High Speed ◽  
Near Field ◽  
Phase Shifting ◽  
Flat Plates ◽  
Noise Sources ◽  
Sound Sources ◽  
Aerodynamic Sound ◽  
Phase Shifting Interferometry ◽  
Pressure Fields

Abstract Aerodynamic sound is one of the causes of noise in high-speed trains, automobiles, and wind turbines. To investigate the characteristics of aerodynamic sound generation, measurements around the sound sources are required. Aerodynamic sound is typically measured using microphones. However, microphones cannot capture the near-field of aerodynamic sound because they become new noise sources inside the air flow. To observe the aerodynamic sound near-field, we performed two-dimensional visualization of aerodynamic sound using an optical method. The optical method used in this research, parallel phase-shifting interferometry (PPSI), can detect the pressure within the measurement area as variations of the phase of light. PPSI can therefore visualize the pressure fields. We visualized both the sound pressure and flow components of the sound generated by flow around a square cylinder and flat plates. The visualized pressure fields are provided as animations in the online resources. Analysis of the sound and flow component time variations confirmed the correlations between them. Graphic abstract

Acquisition of 3-D Optical Information

1989 ◽  
Vol 1 (4) ◽  
pp. 255-255
Author(s):  
Masanori Idesawa
Keyword(s):  
Optical Method ◽  
High Speed ◽  
Distance Measurement ◽  
Optical Systems ◽  
Target Point ◽  
Optical Information ◽  
Universal Method ◽  
Distance Information ◽  
Speed Measurement

In order for a machine to have the capacity to operate flexibly in a 3-D environment, it is indispensable for it to be equipped with space information acquisition capability, and tools for distance measurement are in turn indispensable for obtaining space information. Indeed distance measurement is basic and important not only for a robot, but also for science and technology in general. Many methods have been proposed for obtaining distance information, ranging from the mechanical contact type through optical and acoustic to electric and magnetic methods, and many are in practical use. Among them the optical method permits measurement of distance without contact and from a remote position, advantages which have led to it being widely applied. One of the most important principles for measuring distance is the triangulation principle. This permits determination of the position of an object from the distance between two observation points together with the angles in the triangle formed by these two points and a target point on the object. Based on this principle, the detection of one specific point in each of the two images obtained from two sets of image input equipment installed at two observation points permits determination of coordinate values in 3-D space. However, this extraction of the point in the second image corresponding to a specified point in the first image is a very difficult subject of study, and no universal method has been developed. To cope with this, active methods, which evade the problem by applying projection of laser light on the surface of an object to identify a bright point or bright line, are widely used. The special feature articles on obtaining 3-D optical information in this issue present some principles and new trial applications of distance acquisition methods for 3-D information, the optical method in particular. There are three reports on active method optical systems developed for robots. These include (1) a high speed measurement method applying space encoding which employs a liquid crystal lattice to project light in changing lattice patterns onto an object dynamically; (2) realization of high speed measurement through projecting and processing multiple light spots; (3) development of a visual sensor for disaster prevention use which can detect objects in flames and smoke utilizing projection of a CO2 gas laser. These are nearly at the level of operational use and are expected to become visual sensors for robots.

Optical Measurements of Unducted Fan Flutter

1991 ◽  
Author(s):  
Anatole P. Kurkov ◽  
Oral Mehmed
Keyword(s):  
Wind Tunnel ◽  
Mode Shape ◽  
Optical Method ◽  
High Speed ◽  
Nonlinear Vibrations ◽  
Optical Measurements ◽  
Optical Data ◽  
Strain Gages ◽  
Trailing Edge ◽  
Blade Tip

The paper describes a nonintrusive optical method for measuring flutter vibrations in unducted fan or propeller rotors and provides detailed spectral results for two flutter modes of a scaled unducted fan. The measurements were obtained in a high-speed wind tunnel. A single-rotor and a dual-rotor counterrotating configuration of the model were tested; however, only the forward rotor of the counterrotating configuration fluttered. Conventional strain gages were used to obtain flutter frequency; optical data provided complete phase results and an indication of the flutter mode shape through the ratio of the leading- to trailing-edge flutter amplitudes near the blade tip. In the transonic regime the flutter exhibited some features that are usually associated with nonlinear vibrations. Experimental mode shape and frequencies were compared with calculated values that included centrifugal effects.

scholarly journals Optical method for fuel atomization control using high-speed video

2020 ◽  
Vol 16 (2) ◽  
pp. 19-26
Author(s):  
Alexander V. Eskov ◽  
Ivan I. Kiryushin
Keyword(s):  
Optical Method ◽  
High Speed ◽  
Video Camera ◽  
Optical Methods ◽  
Atmospheric Conditions ◽  
High Speed Video ◽  
Fuel Atomization ◽  
High Speed Video Camera ◽  
Fuel Jet ◽  
Surface Diameter

The article discusses the description of one of the optical methods for determining the parameters of fuel atomization in atmospheric conditions and recording the results using a high-speed video camera. The possibility of interpreting images of a fuel jet in development over time as the distribution of the concentration of a dispersed medium with a constant volume-surface diameter (Sauter), which is an optical method for controlling fuel atomization, is shown.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

The on-line use of histogram data for high-speed correction and alignment of electron microscope images

1984 ◽  
Vol 42 ◽  
pp. 556-557
Author(s):  
William Krakow
Keyword(s):  
Power Spectrum ◽  
High Speed ◽  
Direct Memory Access ◽  
Digital Television ◽  
Contrast Transfer Function ◽  
The Past ◽  
High Resolution Tem ◽  
On Line ◽  
Correction Of Astigmatism ◽  
The Fourier Transform

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.

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