The Microscope - Volume 58, Fourth Quarter 2010
IN THIS ISSUE:
On the cover: Orthochrysotile from Thetford Mines, Quebec, Canada, viewed in crossed polarized light at 200X magnification. See Use of Malachite Green Stain as an Auxiliary Technique for Differentiation of Asbestiform Sepiolite From Chrysotile Asbestos by Lou Solebello.
Editorial: Lucy B. McCrone, 1923-2011
Gary J. Laughlin
The Microscope 58 (4), p ii
Excerpt: Just before going to press with this issue of The Microscope, I received the sad news of the death of my dear friend, colleague and mentor of 23 years, Lucy B. McCrone. McCrone Research Institute’s co-founder and matriarch succumbed to complications from pancreatic cancer on February 10. She was 87 years old. Full article (PDF)
SEM Characterization of Epitaxially Grown Aluminum Oxide Employed as Sensor Substrates
Martin Kocanda and Bryn M. Wilke
The Microscope 58 (4), pp 147-158
Abstract: Anodic aluminum oxide (AAO) films have been used as protective coatings since the 1950s and more recently as a decorative metallic finish. The porosity, surface morphology and fabrication methods of these films have been studied extensively. Common to the commercial AAO films is the anodization process of aluminum fabricated in the (100) crystallographic plane using inorganic electrolytes. A more recent application of this anodic process, using low solubility salts, has been the fabrication of hexagonal templates to grow domains of nanowires and nanotubes.
The use of microelectronic fabrication methods to epitaxially grow (111) aluminum thin films, and the subsequent anodization method, has been recently employed to implement nanostructured AAO materials as commercial moisture sensors and as substrates to study the adsorption response of volatile organic compounds (VOCs) and biochemical compounds. These epitaxially grown films contain nanoporous structures having pore morphologies similar to the (100) film but appear to grow radially from the tetrahedral and hexagonal domains. In this work, the surface morphology of epitaxially grown porous nanostructures is elucidated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Full article (PDF)
Use of Malachite Green Stain as an Auxiliary Technique for Differentiation of Asbestiform Sepiolite From Chrysotile Asbestos
The Microscope 58 (4), pp 161-166
Abstract: Most matrixes submitted to environmental laboratories for asbestos analysis are considered routine and do not present unique analytical challenges. Occasionally, materials are encountered that contain non-regulated asbestiform minerals, which can be misidentified as asbestos. The clay mineral sepiolite, Mg4Si6O15 (OH)2·6H2O, can be asbestiform and is used as a substitute to chrysotile, Mg3Si2O5(OH)4 in some applications. Asbestiform sepiolite is structurally, compositionally and optically similar to chrysotile, which can exhibit a variability that complicates differentiation. The similarity of sepiolite to chrysotile, combined with chrysotile compositional variability, can result in false positives. Malachite green stain is a relatively simple and quick technique for differentiation of sepiolite from chrysotile in conjunction with polarized light microscopy (PLM) analysis. Full article (PDF)
Critical Focus | The Good Guide to Bad Lectures
Brian J. Ford
The Microscope 58 (4) pp 167-172
Excerpt: Do you love the sound of your own voice? Are you wrapped up in a state of rapture by the sight of an audience? Have you learned all there is to know about presenting your work in public? Are you far more knowledgeable than the folks in the audience? If the answers are yes, then please, whatever else you do, never give a lecture. Those are all the wrong reasons. You’re there to please the people, not yourself. The only individuals who should ever pontificate at a conference are those who may know their subject, but who are profoundly worried about doing it well. Good lecturers begin as poor speakers. People learn more when things go wrong, rather than when they’re doing it right, and in time they improve. This is Lecture Darwinism at work. Full article (PDF)
Tricks of the Trade | Making a Custom Microscope Shield
The Microscope 58 (4), pp 175-176
Excerpt: While a skilled microscopist is able to manually minimize sample loss and contamination, there is still a need to be cleaner and safer. A microscope shield provides an ideal barrier of protection. The least expensive microscope shields available from science supply companies sell for around $40. These shields have fixed dimensions and cannot be customized. This “Tricks of the Trade” method explains how to make an inexpensive alternative that can be easily fitted on any microscope. Full article (PDF)
The Microscope Past: 50 Years Ago | Conifer Needles
Sonia Turler, Hans-Rudolf Birchler and Ernst Woessner
The Microscope 58 (4), p 177-179. Originally published in The Microscope, Vol. 12, No. 9, July-August 1960.
Excerpt: Conifer needles form an interesting and rewarding subject for microscopical study. The needles are easy to section, and after staining, make attractive permanent mounts. There is also the advantage that, with the exception of those of the larch, material can be found at any time of the year. This article is intended as an encouragement to others to try it for themselves, and as an introduction to the subject for those who may go further into the matter. Full article (PDF)
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