Microstructural characterisation of the Ypresian clays (Kallo-1) at nanometre resolution, using broad-ion beam milling and scanning electron microscopy

AbstractBesides the Oligocene Boom Clay, the Ypresian clays – part of the Eocene Ieper Group (Kortrijk Formation and Kortemark Member) – are currently being investigated as an alternative host rock for the deep geological disposal of radioactive waste in Belgium and the Netherlands. In this study, broad-ion-beam milling and high resolution scanning electron microscopy (BIB-SEM) analyses were carried out to analyse the mineral fabrics and microstructures of representative Ypresian clay samples from different depths of the ON-Kallo-1 borehole (Kallo, Belgium). Qualitative microstructural observations indicate that mineral fabrics and pore morphologies in fine-grained samples are comparable to those found for fine-grained Boom Clay, but most of the Ypresian clay samples analysed also contained a significant silt fraction, which is associated with larger inter-aggregate pores, coated by a thin, very low porous clay layer. Quantitative pore-shape analysis shows lower axial ratios and elongations, as well as higher roundness and circularities for pores in the clay matrix of the more coarse-grained samples, compared to the fine-grained samples. The contribution of large pores (>1 × 107nm² pore area) to the total BIB-SEM observed porosity was found to correlate with the non-clay mineral (NCM) content of a sample. Frequencies of pore sizes within the clay matrix follow a power-law distribution, hinting towards the possibility of up-scaling of the nanometre-scale observations to larger scale (micro-) structural features of the material. Power-law exponents are comparable to values found for power-law pore-size distributions within the clay matrix of the Boom Clay, which indicates similarity of the pore-space morphologies within the clay matrix of the Boom Clay and the Ypresian clays. Wood's metal injection, followed by (cooled BIB)-SEM analysis shows that all visible pores are connected via pore throats of diameter down to ~10 nm.

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Pore space characteristics of the Upper Visean ‘Rudov Beds’: insights from broad ion beam scanning electron microscopy and organic geochemical investigations

Geological Society London Special Publications ◽

10.1144/sp484.9 ◽

2018 ◽

Vol 484 (1) ◽

pp. 205-228 ◽

Cited By ~ 1

Author(s):

D. Misch ◽

J. Klaver ◽

D. Gross ◽

J. Rustamov ◽

R. F. Sachsenhofer ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Pore Space ◽

Ion Beam ◽

Porous Solid ◽

Donets Basin ◽

Beam Scanning ◽

Solid Bitumen ◽

Pore Size Distributions ◽

Scanning Electron

AbstractThis study gives valuable insights into the microstructure and pore space characteristics of 17 compositionally variable Visean shale samples from the Ukrainian Dniepr-Donets Basin (the ‘Rudov Beds’). The representative imaging area varies considerably (from 10 000 to >300 000 µm2) as a function of the mineralogy and diagenetic overprinting. The pores hosted in organic matter (OM) are restricted to secondary solid bitumen. Based on high-resolution maps from broad ion beam scanning electron microscopy combined with organic geochemical and bulk mineralogical data, we propose that the amount of OM-hosted porosity responds to the availability of pore space, enabling the accumulation of an early oil phase, which is then progressively transformed to a porous solid bitumen residue. The type of OM porosity (pendular/interface v. spongy) is reflected in the individual pore size distributions: the spongy pores are usually smaller (<50 nm) than the pendular or OM–mineral interface pores. The OM-hosted porosity coincides with differences in the composition of the extract, with high amounts of extractable OM and saturated/aromatic compound ratios indicative of abundant porous solid bitumen. The average circularity and aspect ratio of the mineral matrix pores correlate with the corresponding values for the OM-hosted pores, which show a preferred bedding-parallel orientation, suggesting that compaction influenced both types of pore.

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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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