A Method for Determination of Particle Penetration Depths in a Filter

Nature ◽  
1958 ◽  
Vol 182 (4647) ◽  
pp. 1437-1438 ◽  
Author(s):  
JAN SISEFSKY
Keyword(s):  
Particle Penetration ◽  
Penetration Depths

The AC-Indentation Technique and its Application to Al and Al-Si Coatings

1991 ◽  
Vol 226 ◽  
Author(s):  
T.W. Wu
Keyword(s):  
Penetration Depth ◽  
High Sensitivity ◽  
Small Displacement ◽  
Depth Profiles ◽  
Indentation Technique ◽  
Indentation Process ◽  
Microindentation Technique ◽  
Penetration Depths ◽  
Selection Of

AbstractAn ac-microindentation technique, namely indenting with a small displacement modulation superimposed on an otherwise linear indenter motion, will be introduced. The basic principle and theory will also be illustrated by using a mechanical model to simulate the indenter behavior.Other than being as capable as conventional indentation, the ac-technique acquires the unloading slope simultaneously and continuously with the penetration depth and applied load during an entire indentation process. With this extra information, the conversion between the total depth and plastic depth can be executed right after a single indentation, and in turn the hardness as well as. contact modulus depth profiles can be calculated. This is in contrast to the conventional indentation technique where a group of indentations associated with different maximum loads are required in order to achieve the same purpose. Furthermore, it also avoids the subjectivity in the selection of the fitting portions from the unloading stage of an indentation curve to extract the unloading slopes as well as the plastic penetration depths.Another important advantage of using this ac-technique is the high sensitivity in detecting the indenter/surface contact. This advantage is very useful in the determination of the origins of penetration depths as well as in the investigation the evolution of the contact area, and both issues are very crucial in the microhardness calculations.The strain rate effect on the hardness measurements of a 1 μm thick Al-2%Si coating has been demonstrated by using the ac-technique. As the indenter loading speed increases from 2.5 to 10 nm/sec, the measured hardness of the coating can be increased from ∼20% to ∼80% depending on the penetration depth, and the shallower the penetration depth the larger the increment is. However, the contact modulus depth profiles remain unchanged for all the indentation rates.

Determination of Particle Penetration Factors in a Particle Transfer Line for Aero Gas Turbine Engine Exhaust Particle Measurement

2014 ◽  
Author(s):  
Mohamed A. Altaher ◽  
Hu Li ◽  
Paul Williams ◽  
Mark Johnson ◽  
Simon Blakey
Keyword(s):  
Critical Issue ◽  
Aircraft Engines ◽  
Measurement Instruments ◽  
Engine Exhaust ◽  
Particle Emissions ◽  
Reliable Determination ◽  
Particle Penetration ◽  
Transfer Line ◽  
Particle Measurement

There is a need to develop a reliable and standard PM (Particulate Matter) measurement method for aircraft engines. Due to safety and practicability of such measurements, a distance is required for the transportation of the exhaust samples from the aircraft engine exhaust exit to particle measurement instruments. The particle line loss during the transportation is therefore a critical issue for the accurate and reliable determination of particle emissions from aircraft engines. The work in this paper investigated the particle penetration/loss along a 25 meters ARP proposed particle sample transfer line by measuring the particle emissions from an aircraft auxiliary power unit (APU) at idle and full power. Two SMPS instruments were used to simultaneously measure exhaust particle size distributions at the entrance and exit of the 25 m transfer line. A catalytic stripper was used to remove volatile particles so that non-volatile particles can be measured. The particle penetration factors for the 25 m transfer line were found to be 0.6∼0.7 in general, excluding particles smaller than 10 nm. For the particles smaller than 10nm, particle penetrations were very poor and about 70–100% of parcel losses were observed. The volatile factions were roughly 20∼30% of the total concentrations.

Generation and Determination of Compressive Residual Stresses of Short Penetration Depths

2013 ◽  
Vol 768-769 ◽  
pp. 580-586 ◽  
Author(s):  
Regina Weingärtner ◽  
Jürgen Hoffmeister ◽  
Volker Schulze
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Fatigue Limit ◽  
Electrochemical Machining ◽  
Beneficial Effects ◽  
Integral Width ◽  
High Gradients ◽  
Stress States ◽  
Penetration Depths

Generating compressive residual stress states with high gradients and low penetration depths offers high capability regarding increase of fatigue limit of parts. In this work the determination of such specific residual stress distributions by using X-ray diffraction and a little material removal is introduced. Measurements are compared using two interference peaks of different penetration depths, at which confocal microscopy enables high accuracy in determination of the step sizes in electrochemical machining. Furthermore the realisation of these states by two different peening processes using micro blasting media is described. The suitability of the processes micro peening and ultrasonic wet peening as surface treatment methods to improve fatigue limit are shown. Micro peening is based on the shot peening principle with small shots and ultrasonic wet peening on the acceleration of small blasting particles by cavitation. The investigations were conducted at AISI 4140 in a quenched and tempered state. Besides the residual stresses and the integral width of interference peaks as well as the depth distributions, the surface topography was examined. The beneficial effects of these conditions on the fatigue limit in bending tests are described.

Collision of a comet with Jupiter: Determination of fragment penetration depths from the molecular spectra

JETP Letters ◽  
1996 ◽  
Vol 63 (6) ◽  
pp. 405-410 ◽  
Author(s):  
A. A. Berezhnoi ◽  
V. V. Shevchenko ◽  
B. A. Klumov ◽  
V. E. Fortov
Keyword(s):  
Molecular Spectra ◽  
Penetration Depths
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