scholarly journals The mechanisms of cavitation erosion of raw and sintered basalt

2019 ◽  
Vol 51 (4) ◽  
pp. 409-419 ◽  
Author(s):  
Marko Pavlovic ◽  
Marina Dojcinovic ◽  
Radica Prokic-Cvetkovic ◽  
Ljubisa Andric
Keyword(s):  
Image Analysis ◽  
Electron Microscope ◽  
Cavitation Erosion ◽  
Test Method ◽  
Cavitation Damage ◽  
G 32 ◽  
Cavitation Effect ◽  
Time Of Operation

The paper analyzes the morphology of cavitation damage of raw and sintered basalt samples. The experiment was conducted using the ultrasonic vibratory cavitation test method according to the ASTM G-32 standard. During the determination of the resistance to the effect of cavitation, a change in the mass of samples was observed in the function of the cavitation time of operation. The morphology of damage caused by the effect of cavitation was followed by scanning with an electron microscope, and the level of degradation of the surface of the samples was quantified using the image analysis. The results showed a significantly higher degree of resistance of sintered basalt, with a cavitation rate of 0.019 mg/min relative to raw basalt, with a cavitation rate of 0.738 mg/min. After 120 minutes of exposure to the cavitation effect, a smaller number of small pits on the surface of sintered basalt were observed, while a higher level of damage to the surface with the appearance of numerous pits was found in raw basalt, which can be connected in some places to larger and deeper pits in some places. The obtained results indicate the possibility of using sintered basalt for the production of parts that will be exposed to the effects of high cavitation loads.

Microstructure of Copper Alloy Effects on Cavitation Damage

2011 ◽  
Vol 239-242 ◽  
pp. 575-579
Author(s):  
Wen Jing Xing
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Copper Alloy ◽  
Cavitation Erosion ◽  
Nacl Solution ◽  
Cavitation Damage ◽  
Transmission Electron ◽  
The Matrix ◽  
Scanning Electron

The cavitation erosion behavior of ZQAl9-4-4-2 nickel-alum inium bronze in 2.4%NaCl solution was investigated by using a magnetostrictive – induced cavitation facility. The micrographs of damaged surface were observed by scanning electron microscope (SEM) and transmission electron microscopy(TEM). The results showed that the cavitation microcrack in the a phase adjacent to the k phase. They propagated and connected with each other in the a phases, resulted in the removal of a phases and detachment of the kphase from the matrix in the following test period followed. The microcracks tended to propagate parallelly to the eroded surfaces.

scholarly journals Determination of resistance to cavitation of pyrophyllite samples

2021 ◽  
Vol 62 (2) ◽  
pp. 126-134
Author(s):  
Ljubiša Andrić ◽  
Marko Pavlović ◽  
Marina Dojčinović ◽  
Dragan Radulović
Keyword(s):  
Electron Microscopy ◽  
Cavitation Erosion ◽  
Surface Damage ◽  
Test Method ◽  
Test Time ◽  
Cavitation Resistance ◽  
Initial Sample ◽  
Erosion Test ◽  
Scanning Electron

The resistance under the action of cavitation of sintered pyrophillite samples was investigated. The initial sample of pyrophillite from the Parsovic-BiH deposit was ground a vibrating mill to a granulation of 20 mm, pressed and sintered at temperatures (⁰C): 100; 1100; 1200. To assess cavitation resistance, the change in sample mass as a function of cavitation time was monitored. The cavitation erosion test was performed using the ultrasonic vibratory cavitation test method according to the ASTM G-32 standard. Cavitation velocites were calculated for all samples, as a basic indicator of the resistance of the material under the action of cavitation. The change in the morphology of the surface with the test time was followed by scanning electron microscopy. Based on the values of cavitation velocity and analysis of the surface damage morphology, the cavitation resistance of the tested samples based on pyrophillite was determined. The obtained results indicate that the samples of sintered pyrophillite have satisfactory resistance to the action of cavitation and be applied in conditions of lower cavitation loads.

The Analysis of Dislocations Using a Symmetry Criterion

1972 ◽  
Vol 30 ◽  
pp. 660-661
Author(s):  
J. C. Ingram ◽  
P. R. Strutt ◽  
Wen-Shian Tzeng
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Displacement Field ◽  
Standard Technique ◽  
Residual Image ◽  
Symmetry Criterion

The invisibility criterion which is the standard technique for determining the nature of dislocations seen in the electron microscope can at times lead to erroneous results or at best cause confusion in many cases since the dislocation can still show a residual image if the term is non-zero, or if the edge and screw displacements are anisotropically coupled, or if the dislocation has a mixed character. The symmetry criterion discussed below can be used in conjunction with and in some cases supersede the invisibility criterion for obtaining a valid determination of the nature of the dislocation.The symmetry criterion is based upon the well-known fact that a dislocation, because of the symmetric nature of its displacement field, can show a symmetric image when the dislocation is correctly oriented with respect to the electron beam.

Feasibility of Molecular Structure Determination With a High Resolution Electron Microscope

1968 ◽  
Vol 26 ◽  
pp. 338-339
Author(s):  
T. A. Welton
Keyword(s):  
Electron Microscope ◽  
Substrate Surface ◽  
Helical Axis ◽  
Base Plane ◽  
Resolution Electron ◽  
High Resolution Electron Microscope ◽  
High Degree ◽  
Degree Of Order ◽  
Purine Pyrimidine

An ultimate design goal for an improved electron microscope, aimed at biological applications, is the determination of the structure of complex bio-molecules. As a prototype of this class of problems, we propose to examine the possibility of reading DNA sequence by an imaginable instrument design. This problem ideally combines absolute importance and relative simplicity, in as much as the problem of enzyme structure seems to be a much more difficult one.The proposed technique involves the deposition on a thin graphite lamina of intact double helical DNA rods. If the structure can be maintained under vacuum conditions, we can then make use of the high degree of order to greatly reduce the work involved in discriminating between the four possible purine-pyrimidine arrangements in each base plane. The phosphorus atoms of the back bone form in projection (the helical axis being necessarily parallel to the substrate surface) two intertwined sinusoids. If these phosphorus atoms have been located up to a certain point on the molecule, we have available excellent information on the orientation of the base plane at that point, and can then locate in projection the key atoms for discrimination of the four alternatives.

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

A quantitative image analysis method for the determination of cocontinuity in polymer blends

1993 ◽  
Vol 51 ◽  
pp. 894-895
Author(s):  
William A. Heeschen
Keyword(s):  
Image Analysis ◽  
Polymer Blends ◽  
Quantitative Measurement ◽  
Morphological Evolution ◽  
Phase Ratio ◽  
Irregular Shapes ◽  
Quantitative Image ◽  
Discrete Domains ◽  
A Domains

Two new morphological measurements based on digital image analysis, CoContinuity and CoContinuity Balance, have been developed and implemented for quantitative measurement of morphology in polymer blends. The morphology of polymer blends varies with phase ratio, composition and processing. A typical morphological evolution for increasing phase ratio of polymer A to polymer B starts with discrete domains of A in a matrix of B (A/B < 1), moves through a cocontinuous distribution of A and B (A/B ≈ 1) and finishes with discrete domains of B in a matrix of A (A/B > 1). For low phase ratios, A is often seen as solid convex particles embedded in the continuous B phase. As the ratio increases, A domains begin to evolve into irregular shapes, though still recognizable as separate domains. Further increase in the phase ratio leads to A domains which extend into and surround the B phase while the B phase simultaneously extends into and surrounds the A phase.

Tire Treadwear — A Comprehensive Evaluation of the Factors: Generic Type, Aspect Ratio, Tread Pattern, and Tread Composition Part I: Introduction and Details on the Organization of the Program

1986 ◽  
Vol 14 (4) ◽  
pp. 201-218 ◽  
Author(s):  
A. G. Veith
Keyword(s):  
Aspect Ratio ◽  
Comprehensive Evaluation ◽  
Test Method ◽  
Interactive Effects ◽  
Data Analyses ◽  
Main Effect ◽  
Systematic Determination ◽  
Relationship Of ◽  
The Relationship

Abstract This four-part series of papers addresses the problem of systematic determination of the influence of several tire factors on tire treadwear. Both the main effect of each factor and some of their interactive effects are included. The program was also structured to evaluate the influence of some external-to-tire conditions on the relationship of tire factors to treadwear. Part I describes the experimental design used to evaluate the effects on treadwear of generic tire type, aspect ratio, tread pattern (groove or void level), type of pattern (straight rib or block), and tread compound. Construction procedures and precautions used to obtain a valid and functional test method are included. Two guiding principles to be used in the data analyses of Parts II and III are discussed. These are the fractional groove and void concept, to characterize tread pattern geometry, and a demonstration of the equivalence of wear rate for identical compounds on whole tread or multi-section tread tires.

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