Optical inspection of laser drilled cooling holes in jet engine blades

In ultramicrotomy, the two basic tool materials are glass and diamond. Glass because of its low cost and ease of manufacture of the knife itself is still widely used despite the superiority of diamond knives in many applications. Both kinds of knives produce plastic deformation in the microtomed section due to the nature of the cutting process and microscopic chips in the edge of the knife. Because glass has no well defined slip planes in its structure (it's an amorphous material), it is very strong and essentially never fails in compression. However, surface flaws produce stress concentrations which reduce the strength of glass to 10,000 to 20,000 psi from its theoretical or flaw free values of 1 to 2 million psi. While the microchips in the edge of the glass or diamond knife are generally too small to be observed in the SEM, the second common type of defect can be identified. This is the striations (also termed the check marks or feathers) which are always present over the entire edge of a glass knife regardless of whether or not they are visable under optical inspection. These steps in the cutting edge can be observed in the SEM by proper preparation of carefully broken knives and orientation of the knife, with respect to the scanning beam.

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Material analysis techniques using the ion mill

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100167639 ◽

1996 ◽

Vol 54 ◽

pp. 1034-1035

Author(s):

J. P. Benedict ◽

R. M. Anderson ◽

S. J. Klepeis

Keyword(s):

Polished Surface ◽

Surface Material ◽

Analysis Techniques ◽

Material Analysis ◽

Optical Inspection ◽

Electron Microscopy Analysis ◽

Microscopy Analysis ◽

Argon Ions ◽

The Impact ◽

Scanning Electron

Ion mills equipped with flood guns can perform two important functions in material analysis; they can either remove material or deposit material. The ion mill holder shown in Fig. 1 is used to remove material from the polished surface of a sample for further optical inspection or SEM ( Scanning Electron Microscopy ) analysis. The sample is attached to a pohshing stud type SEM mount and placed in the ion mill holder with the polished surface of the sample pointing straight up, as shown in Fig 2. As the holder is rotating in the ion mill, Argon ions from the flood gun are directed down at the top of the sample. The impact of Argon ions against the surface of the sample causes some of the surface material to leave the sample at a material dependent, nonuniform rate. As a result, the polished surface will begin to develop topography during milling as fast sputtering materials leave behind depressions in the polished surface.

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Human resources sensitivity to system design tradeoff alternatives: Feasibility test with jet engine data.

PsycEXTRA Dataset ◽

10.1037/e440862004-001 ◽

1973 ◽

Author(s):

William B. Askren ◽

Kenneth D. Korkan ◽

George W. Watts

Keyword(s):

Human Resources ◽

System Design ◽

Jet Engine ◽

Feasibility Test

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DETERMINATION OF THE TYPE OF A SINGLE-USE GRENADE LAUNCHER BASED ON ITS COMPOSITE PARTS AND FRAGMENTS OF REACTIVE GRENADE FOUND AT THE PLACE OF ACCIDENT

Theory and Practice of Forensic Science and Criminalistics ◽

10.32353/khrife.2017.31 ◽

2017 ◽

Vol 17 ◽

pp. 245-252

Author(s):

V. V. Somov

Keyword(s):

Combustion Chamber ◽

Structural Features ◽

Outlet Section ◽

Technical Expertise ◽

Jet Engine ◽

Size Ofthe ◽

Single Use ◽

Nozzle Block ◽

Considerable Damage

In carrying out an investigation into the explosion, among others, the investigative version of the use of a single-use reactive grenade launcher is being considered. The most common for criminal explosions are applied grenade launchers RPG-18, RPG-22, RPG-26. Their use is due to a number of such properties as small size and weight, which makes it possible to transfer them covertly, the range of the shot significantly exceeding the range of the hand grenade throw, the high detonating effect of the rocket grenade explosion. The single-use rocket launchers are generally of the same design. Their differences are in the features of the components construction and dimensional characteristics, which are given in the article. On the basis of expert practice, details ofgrenade launchers that remain at the site of the explosion and have the least damage are determined. These details are the objects of investigation of the explosion technical expertise. These objects include launchers of grenade launchers and rocket parts ofjet grenades. The design features of the launchers, their dimensional characteristics and marking symbols make it possible to determine their belonging to a specific type of jet grenade launchers. Missile parts of jet grenades differ in the form of the combustion chamber of the jet engine, nozzle, in the size ofthe outlet section of the nozzle, in the form and size of the stabilizerfeathers. To determine the belonging of the rocket part of the grenade to a specific type ofjet grenade launcher, it’s necessary to establish a set of structural features and dimensional characteristics. At considerable damage of the combustion chamber of the jet engine, as a rule, the nozzle block remains intact that allows to define diameter of critical section of a nozzle, and on it to establish type of the used single-use grenade launcher.

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