Subsurface deformation of steel by solid particle impact investigated by ion beam slope cutting and scanning electron microscopy

In recent years, polyethylene (PE) has found increasing use in applications involving impact and erosion. This paper describes a detailed study of the properties of PE subjected to solid particle impact. Flat discs of the material were eroded by sieved sand (300-600 pm) accelerated by using an air blast rig in which the important variables of velocity, angle and mass flux rate are accurately controllable and measurable. Scanning electron microscopy of lightly eroded specimens enabled four basic crater types to be identified: smooth, ploughed, cut, and dented. The proportions of each were established over a range of angles. Long time erosion experiments were conducted in which the flux rate for each angle was adjusted to keep the number of impacts per unit time constant. The dimensionless erosion parameter, e (mass lost per unit mass of erodent that has struck) was computed by using the rate of mass loss when steady-state erosion had been established. Most erosion was found to occur at an angle of 20—30°, the mass loss becoming zero at around 80°. An analysis by D. R. Andrews is presented, showing that the flux rates used in these experiments are well below those needed to cause wear by thermal mechanisms, and this was confirmed by changing the flux rate: mass loss increased in proportion. Macroscopic particles were used to model sand grain impacts, spheres for rounded particles and square plates for sharp ones. A range of techniques was used in this study including high-speed photography (framing speed of 5 x 10 4 s -1 ), scanning electron microscopy, and moire methods (both in-plane and out-of-plane). A deformation map was constructed for steel sphere im pacts giving the type of crater to be expected at a given angle and speed. It was observed that sand grains required much lower speeds at a given angle to produce a given crater type. High-speed photography enabled mass-loss mechanisms for single-particle impact to be identified. These were the drawing-out of filaments and the machining-out of chips. Quantitative data on kinetic energy losses were obtained, and these, combined with moire methods that gave the sizes of deformed zones, enabled an estimate of the temperature rise per impact to be made (25 K).

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Ultrastructural Features of Normal and Diseased Hair Revealed by Ion Beam Etching and Freeze Fracture

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115419 ◽

1975 ◽

Vol 33 ◽

pp. 358-359

Author(s):

M. Spector ◽

A. C. Brown

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Ectodermal Dysplasia ◽

Ion Beam ◽

Freeze Fracture ◽

Ion Current ◽

Ion Beam Etching ◽

Pili Torti ◽

Argon Ion ◽

Scanning Electron

Ion beam etching and freeze fracture techniques were utilized in conjunction with scanning electron microscopy to study the ultrastructure of normal and diseased human hair. Topographical differences in the cuticular scale of normal and diseased hair were demonstrated in previous scanning electron microscope studies. In the present study, ion beam etching and freeze fracture techniques were utilized to reveal subsurface ultrastructural features of the cuticle and cortex.Samples of normal and diseased hair including monilethrix, pili torti, pili annulati, and hidrotic ectodermal dysplasia were cut from areas near the base of the hair. In preparation for ion beam etching, untreated hairs were mounted on conducting tape on a conducting silicon substrate. The hairs were ion beam etched by an 18 ky argon ion beam (5μA ion current) from an ETEC ion beam etching device. The ion beam was oriented perpendicular to the substrate. The specimen remained stationary in the beam for exposures of 6 to 8 minutes.

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Microscopy Methods for Biofilm Imaging: Focus on SEM and VP-SEM Pros and Cons

Biology ◽

10.3390/biology10010051 ◽

2021 ◽

Vol 10 (1) ◽

pp. 51

Author(s):

Michela Relucenti ◽

Giuseppe Familiari ◽

Orlando Donfrancesco ◽

Maurizio Taurino ◽

Xiaobo Li ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Ion Beam ◽

Ruthenium Red ◽

Variable Pressure ◽

Sem Images ◽

Advantages And Disadvantages ◽

Pros And Cons ◽

Microscopy Techniques ◽

Scanning Electron

Several imaging methodologies have been used in biofilm studies, contributing to deepening the knowledge on their structure. This review illustrates the most widely used microscopy techniques in biofilm investigations, focusing on traditional and innovative scanning electron microscopy techniques such as scanning electron microscopy (SEM), variable pressure SEM (VP-SEM), environmental SEM (ESEM), and the more recent ambiental SEM (ASEM), ending with the cutting edge Cryo-SEM and focused ion beam SEM (FIB SEM), highlighting the pros and cons of several methods with particular emphasis on conventional SEM and VP-SEM. As each technique has its own advantages and disadvantages, the choice of the most appropriate method must be done carefully, based on the specific aim of the study. The evaluation of the drug effects on biofilm requires imaging methods that show the most detailed ultrastructural features of the biofilm. In this kind of research, the use of scanning electron microscopy with customized protocols such as osmium tetroxide (OsO4), ruthenium red (RR), tannic acid (TA) staining, and ionic liquid (IL) treatment is unrivalled for its image quality, magnification, resolution, minimal sample loss, and actual sample structure preservation. The combined use of innovative SEM protocols and 3-D image analysis software will allow for quantitative data from SEM images to be extracted; in this way, data from images of samples that have undergone different antibiofilm treatments can be compared.

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