scholarly journals Naturally Occurring Asbestiform Minerals in Italian Western Alps and in Other Italian Sites

2020 ◽  
Vol 26 (1) ◽  
pp. 39-46
Author(s):  
Elena Belluso ◽  
Alain Baronnet ◽  
Silvana Capella
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Field Survey ◽  
Western Alps ◽  
Natural Occurrence ◽  
High Magnification ◽  
Naturally Occurring ◽  
Transmission Electron ◽  
The World ◽  
Asbestiform Minerals

ABSTRACT The natural occurrence of asbestos (NOA) in rocks and soil has been known for many years in several areas of the world, differently from the natural presence of asbestiform minerals. In Italy, the mapping of NOA is mandatory according to the 2001 and 2003 regulations. An investigation, not yet concluded, has revealed that in Italy, NOA is represented by chrysotile and tremolite asbestos with minor amounts of actinolite asbestos and anthophyllite asbestos. A field survey conducted in the Italian Western Alps (IWA), dealing with the natural occurrence of asbestiform minerals non-asbestos classified and not regulated, started many years ago and is still ongoing. It revealed that the following kinds of asbestiform silicates are present (in decreasing order of frequency): asbestiform polygonal serpentine and asbestiform antigorite, asbestiform diopside, asbestiform carlosturanite, asbestiform forsterite, asbestiform sepiolite, asbestiform balangeroite, and asbestiform talc. The asbestiform non-silicates brugnatellite and brucite have been rarely detected. Outside the IWA, asbestiform zeolite (erionite and offretite), asbestiform sodium amphibole (fluoro-edenite), and a few other asbestiform silicates have been also detected. For some asbestiform minerals, the identification is problematic and needs the use of transmission electron microscopy combining imaging at high magnification and electron diffraction and chemical data. This investigation is particularly important to distinguish four kinds of asbestiform minerals (antigorite, polygonal serpentine, carlosturanite, and balangeroite) from chrysotile since only the last one is regulated. The issue is much more complicated by the intergrowth of different fibrous species on the submicrometer scale.

scholarly journals Recent Advances in Transmission Electron Microscopy for Materials Science at the EMAT Lab of the University of Antwerp

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1304 ◽  
Author(s):  
Giulio Guzzinati ◽  
Thomas Altantzis ◽  
Maria Batuk ◽  
Annick De Backer ◽  
Gunnar Lumbeeck ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Materials Science ◽  
Electron Tomography ◽  
High Resolution Imaging ◽  
Rapid Progress ◽  
Transmission Electron ◽  
The World ◽  
Resolution Imaging ◽  
The University

The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium’s foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab’s recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science.

Subcellular Elemental Analysis With the Abalytiual Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 74-75
Author(s):  
J.A. Chandler ◽  
C.K. Chou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Elemental Analysis ◽  
Broad Spectrum ◽  
X Ray ◽  
Transmission Electron ◽  
The World ◽  
First Time ◽  
Water Borne

Water-borne copper-chrome-arsenate preservatives(CCA) are now recognised throughout the world as the most effective broad-spectrum preservatives and are extensively used today for a wider range of purposes than any other preservative type. The mode of action of this preservative against decaying fungi, however, is little known and this paper reports investigations into an understanding of the process of treatment. The combination of transmission electron microscopy and x-ray microanalysis has for the first time allowed an accurate location for analysis of the consistuent elements in this preservative when applied to wood.

Transmission Electron Microscopy of Green Sheet Ceramic Specimens Prepared by Ultramicrotomy

1970 ◽  
Vol 28 ◽  
pp. 464-465
Author(s):  
Ronald M. Anderson ◽  
Fred W. Schneider
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Internal Structure ◽  
High Magnification ◽  
Transmission Electron ◽  
Green Sheet ◽  
Scanning Electron

It is often desirable to make high-magnification observations of the internal structure of green sheet ceramic. Scanning electron microscopy and replication microscopy have been unsatisfactory in studying the structure of green sheet ceramic. The feasibility of another technique, that of combining ultramicrotomy with transmission electron microscopy (TEM), seemed, therefore, worth investigating. Mullite and alumina green sheets were studied.Narrow (1 × 10mm) strips of green sheet ceramic were cut and mounted in “Beem” microtome capsules. A mixture of Cargille NYSEM epoxy embedding materials was prepared and poured into the capsules, care being taken to keep the specimen centered, especially at the tapered end of the capsule.

Ultrastructural assessment of cryofractured primate spermatozoon by analytical scanning electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 246-247
Author(s):  
R. P. Apkarian ◽  
K. Gopalkrishnan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Sample ◽  
High Magnification ◽  
Transmission Electron ◽  
Large Numbers ◽  
Imaging Mode ◽  
Analytical Scanning Electron Microscopy ◽  
Scanning Electron

A cryofracture technique for scanning electron microscopy (SEM) was developed to provide an ultrastructural assessment of large numbers of chimpanzee sperm from a single centrifuged pellet. Normal spermatozoon observed in an analytical SEM at high magnification were used to determine the suitability of this technique for preserving the ultrastructural features of many sperm fractured through different regions. Although transmission electron microscopy (TEM) provides fine ultrastructural imaging of primate spermatozoon, this imaging mode does not provide large numbers of sperm in a single sample which can be rapidly scanned for profiles of ultrastructural abnormalities useful in infertility screening.

scholarly journals Breaking the Resolution Barrier in the Scanning Electron Microscope

2008 ◽  
Vol 16 (6) ◽  
pp. 28-35
Author(s):  
William Vanderlinde
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Spot Size ◽  
High Magnification ◽  
Transmission Electron ◽  
Very High ◽  
Tem Transmission Electron Microscopy ◽  
Scanning Electron

Everyone always wants better resolution from his or her microscopes. With semiconductor manufacturers now shipping product with sub-100 nm gates, measuring features and defects has become a challenge, even for the scanning electron microscope (SEM). For metrology below 100 nm, some manufacturers have begun routinely using TEM (transmission electron microscopy) which is tedious and expensive. As a microscopist, I find this quite disappointing since, in principle, the SEM should be capable of providing more than enough resolution well below 100 nm. Why is it that SEMs with 1 nm spot size can’t provide adequate resolution for 100 nm gates? It turns out that at very high magnification, SEM resolution is limited by how the electron beam interacts with the sample rather than simply the spot size of the beam.

scholarly journals Viral Architecture of SARS-CoV-2 with Post-Fusion Spike Revealed by Cryo-EM

2020 ◽  
Author(s):  
Chuang Liu ◽  
Yang Yang ◽  
Yuanzhu Gao ◽  
Chenguang Shen ◽  
Bin Ju ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clinical Research ◽  
Negative Staining ◽  
S Protein ◽  
Preliminary Results ◽  
Transmission Electron ◽  
The World ◽  
First Time ◽  
Virion Particles

AbstractSince December 2019, the outbreak of Coronavirus Disease 2019 (COVID-19) spread from Wuhan, China to the world, it has caused more than 87,000 diagnosed cases and more than 3,000 deaths globally. To fight against COVID-19, we carried out research for the near native SARS-CoV-2 and report here our preliminary results obtained. The pathogen of the COVID-19, the native SARS-CoV-2, was isolated, amplified and purified in a BSL-3 laboratory. The whole viral architecture of SARS-CoV-2 was examined by transmission electron microscopy (both negative staining and cryo-EM). We observed that the virion particles are roughly spherical or moderately pleiomorphic. Spikes have nail-like shape towards outside with a long body embedded in the envelope. The morphology of virion observed in our result indicates that the S protein of SARS-CoV-2 is in post-fusion state, with S1 disassociated. This state revealed by cryo-EM first time could provide an important information for the identification and relevant clinical research of this new coronavirus.

scholarly journals Comparative palynological analysis of Lygodium venustum Sw. and L. volubile Sw. (Lygodiaceae)

2013 ◽  
Vol 85 (2) ◽  
pp. 699-707 ◽  
Author(s):  
JUAN P. RAMOS GIACOSA ◽  
MARTA A. MORBELLI ◽  
GABRIELA E. GIUDICE
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Polar View ◽  
Middle Layer ◽  
Palynological Analysis ◽  
Herbarium Material ◽  
Equatorial Diameter ◽  
Transmission Electron ◽  
The World ◽  
Polar Diameter

The genus Lygodium Sw. is one of the few climbing ferns in the world. The spores of L. venustum Sw. and L. volubile Sw. were studied using light, scanning, and transmission electron microscopy. This work is based on herbarium material. The spores are trilete, triangular, with straight to convex sides in polar view. The equatorial diameter is 72-104 µm, and the polar diameter is 64-84 µm. The ornamentation in L. venustum is verrucate-tuberculate while in L. volubile, it is verrucate-tuberculate in the proximal face but with a few ridges on the distal face, where a micro-ornamentation constituted by verrrucae and tubercles is observed. An equatorial ridge is also present. The exospore is two-layered; in L. venustum, it is smooth in contrast with the ornamented exospore of L. volubile. The perispore of the two species analyzed is similar. This wall is four-layered with particular elements arranged radially in the middle layer. On the spores surface of both species, few spheroids are observed. The results introduced in the current study may be useful for the systematics of the genus as well as for phylogenetic purposes.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

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