scholarly journals Shape and surface area measurements using scanning electron microscope stereo-pair images of volcanic ash particles

Geosphere ◽  
2010 ◽  
Vol 6 (6) ◽  
pp. 805-811 ◽  
Author(s):  
Owen P. Mills ◽  
William I. Rose
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Area ◽  
Volcanic Ash ◽  
Stereo Pair ◽  
Scanning Electron

scholarly journals Micropore Structure and Fractal Characteristics of Low-Permeability Coal Seams

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Guang-zhe Deng ◽  
Rui Zheng
Keyword(s):  
Fractal Dimension ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Coal Seam ◽  
Linear Relationship ◽  
Surface Area ◽  
Pore Volume ◽  
Low Permeability ◽  
Coal Seams ◽  
Scanning Electron

With the raw coal from a typical low-permeability coal seam in the coalfield of South Junger Basin in Xinjiang as the research object, this paper examined six kinds of coal samples with different permeabilities using a scanning electron microscope and a low-temperature nitrogen adsorption test that employed a JSM-6460LV high-resolution scanning electron microscope and an ASAP2020 automatic specific surface area micropore analyzer to measure all characteristic micropore structural parameters. According to fractal geometry theory, four fractal dimension calculation models of coal and rock were established, after which the pore structure characteristic parameters were used to calculate the fractal dimensions of the different coal seams. The results show that (1) the low-permeability coal seam in the coalfield of South Junger Basin in Xinjiang belongs to mesoporous medium, with a certain number of large pores and no micropores. The varying adsorption capacities of the different coal seams were positively correlated with pore volume, surface area, and the mesoporous surface area proportions, from which it was concluded that mesopores were the main contributors to pore adsorption in low-permeability coal seams. (2) The raw coal pore fractal dimension had a negative linear relationship to average pore size, a positive linear relationship with total pore volume, total surface area, and adsorption capacity, and a positive correlation with the mesoporous surface area proportion; that is, the higher the fractal dimension, the larger the pore volume and surface area of the raw coal. (3) The permeability of the low-permeability coal seam had a phase correlation with the micropore development degree; that is, the permeability had a phase negative correlation with the pore distribution fractal dimension, and there was a positive correlation between permeability and porosity. These results are of theoretical significance for the clean exploitation of low-permeability coal seam resources.

The texture of an english fuller's earth

Clay Minerals ◽  
1982 ◽  
Vol 17 (2) ◽  
pp. 255-258 ◽  
Author(s):  
R. H. S. Robertson ◽  
D. Tessier ◽  
J. L. White
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Lower Cretaceous ◽  
Volcanic Ash ◽  
Glass Fragment ◽  
Basaltic Glass ◽  
Fuller’S Earth ◽  
Scanning Electron

It is generally agreed that the English mid-Jurassic and Lower Cretaceous fuller's earths were derived from volcanic ash. In the Lower Cretaceous fuller's earth of Woburn, Kerr (1932) recognized partially decomposed relics of shards in a matrix of montmorillonite, and Grim (1933, 1935) described montmorillonite pseudomorphs after glass fragments in the Bath fuller's earth of Bathonian age. Jeans et al. (1977) published twenty-two SEM pictures of pyroclasts, including sanidine, sphene, trachytic pumice, and a basaltic glass fragment. Photomicrographs of the Lower Cretaceous fuller's earth show shard relicts ranging in length from 0·8-1·26 mm (median ∼1·12 mm) and in thickness from 5-15µm (Jeans et al., 1977, fig. 14a). However, much remains obscure about the shape, size and mode of packing of the argillized vitric particles which make up the bulk of fuller's earths. This note describes the texture of an English fuller's earth which was freeze-fractured (Tessier, 1978), prior to examination with a scanning electron microscope.

Considerations in Making Stereo Micrographs with the Scanning Electron Microscope - Positioning the Stereo Window

1976 ◽  
Vol 34 ◽  
pp. 508-509
Author(s):  
Earl R. Walter
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Tilt Angle ◽  
Field Of View ◽  
Stereo Pair ◽  
The Difference ◽  
Scanning Electron

A variety of factors must be controlled in order to obtain stereo micrograph pairs with the SEM which provide maximum effectiveness along with ease of viewing. These include the following:1. Where possible, micrographs should be sharp from edge to edge. This may require the use of an Autofocus attachment although somewhat the same effect can be obtained by maintaining the point of sharpest focus near opposite edges of the two micrographs forming the stereo pair.2. The difference in tilt angle between the two micrographs of the pair should be kept in the 4to 6° range to provide a normal perspective.3. Micrographs forming a stereo pair should be made at relatively low tilt angles to prevent large differences in the field of view of the two micrographs and to minimize the left to right magnification variations.

Preparation of Red-Green Stereo Lantern Slides from SEM Micrographs

1972 ◽  
Vol 30 ◽  
pp. 412-413
Author(s):  
Michael Nemanic
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Slide Projector ◽  
Stereo Pair ◽  
Sem Micrographs ◽  
Lantern Slide ◽  
Color Slide ◽  
Scanning Electron

The procedure detailed allows the projection and viewing of stereoscopic slides without the use of a special stereo projector or a polarizing screen; a standard lantern slide projector is used, and the slides are viewed through red and green acetate filters.A stereo pair is taken on a scanning electron microscope with a tilt difference of 7° (Fig. 1). After the first member of the pair is taken, the sample is tilted. The image is refocused by means of the z-axis control and recentered by means of the x- and y-axis controls. These two manipulations ensure that both micrographs in the stereo pair are at the same magnification and that they will be superimposed properly on the color slide.A Polaroid MP-3 Industrial Viewer, a Graflex 120 roll film back, and a framing table (or equivalent equipment) can be used to make stereo slides from stereo pairs.

scholarly journals Synthesis ofMnO2Microfiber with Secondary Nanostructure by Cotton Template

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Huan-qin Wang ◽  
Ming-bo Zheng ◽  
Jin-hua Chen ◽  
Guang-bin Ji ◽  
Jie-ming Cao
Keyword(s):  
Crystal Structure ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Single Crystal ◽  
Surface Area ◽  
Single Crystal Structure ◽  
Bet Surface Area ◽  
Low Concentration ◽  
Adsorption Desorption ◽  
Scanning Electron

HierarchicalMnO2microfibers were prepared by using cotton as the template andKMnO4as the precursor via an ultrasonic assistance route. The results of scanning electron microscope characterization showed that the concentration ofKMnO4had a significant effect on the morphology ofMnO2microfiber. At low concentration ofKMnO4, the microfiber was composed ofMnO2nanorods with single crystal structure. With increasing the concentration ofKMnO4, the secondary nanostructure ofMnO2microfibers had a transformation from nanorod to nanoparticle. The results ofN2adsorption-desorption analysis indicated thatMnO2microfibers had BET surface area of about 25 m2/g. This synthesis provides a new way to control the secondary nanostructure ofMnO2microfiber by adjusting the concentration of precursor. Furthermore, the mechanism for the replication was proposed and discussed.

scholarly journals The Effect of Fly Ash on Some Surface Characteristics and Microstructure of β-C2S

1997 ◽  
Vol 15 (6) ◽  
pp. 407-417
Author(s):  
Kh.A. Khalil ◽  
A.A. Amer
Keyword(s):  
Electron Microscope ◽  
Fly Ash ◽  
Scanning Electron Microscope ◽  
Specific Surface ◽  
Surface Area ◽  
Nitrogen Adsorption ◽  
Surface Characteristics ◽  
Ash Content ◽  
Sem Investigation ◽  
Scanning Electron

The effect of the addition of fly ash (0–15 wt. %) on the surface characteristics of β-C2S and its microstructure was investigated using nitrogen adsorption at −196°C together with scanning electron microscope (SEM) techniques. The results obtained revealed that the addition of fly ash up to 5 wt. % increased the specific surface area by 32% followed by a decrease of 34% when the fly ash content was increased up to 15 wt. %. SEM investigation showed that the hydrates produced form an outer shell which coats the fly ash particles.

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