Recording transmitted beam current for X-ray microanalysis in a scanning transmission electron microscope

A method of measuring transmitted beam current stability during and between X-ray microanalyses in a STEM is described. This facility also allows analytical artefacts due to charging, drift, contamination and mass loss to be detected during an analysis.     

An Indentation Method for Measuring Matrix-Fiber Frictional Stresses in Ceramic Composites

A simple method for measuring frictional stresses between the mairix and individual fibers in a ceramic composite is described. A standard microhardness indenter is used to apply a force to the end of the fiber and depress it below the matrix surface. The frictional stress is calculated from measurement of the applied force and the amount of slipping between the fiber and matrix.     

Effect of surfactant systems on the water sensitivity of latex films

The effects of three different types of surfactant systems (ionic, polymeric, and electrosteric stabilizers) on the water sensitivity of poly(butyl acrylate‐co‐methyl methacrylate) latex films was examined. The water sensitivity was found to be strongly dependent on the surfactant system used in their preparation. A number of factors, such as the surfactant mobility and crystallinity and surfactant/polymer polarity appeared to affect the water uptake of the films. Highly mobile and crystallizable surfactants yielded high water sensitivity for films containing ionic surfactants, whereas the surfactant polarity had a greater effect on latices stabilized by polymeric surfactants, with the more hydrophilic systems providing greater water uptake. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1813–1823, 2004     

Novel, uniform nanostructured catalytic membranes

Nanostructured membrane structures have been fabricated by a combination of anodic aluminum oxidation (AAO) and atomic layer deposition (ALD) for use as platforms for the synthesis of highly uniform heterogeneous catalysts. The ALD method makes it possible to control pore diameters on the Angstrom scale even when the overall pore diameter is 10’s to 100’s of nanometers. AAO membranes imbedded in an aluminum sealing ring have been tested for flow properties and found to follow Knudsen diffusion behavior. Vanadia-coated membranes have been tested for the catalytic oxidative dehydrogenation of cyclohexane and show improved selectivity at the same conversion compared to conventional powdered alumina supported vanadia catalysts.     

A model of diatom shape and texture for analysis, synthesis and identification

We describe tools for automatic identification and classification of diatoms that compare photographs with other photographs and drawings, via a model. Identification of diatoms, i.e. assigning a new specimen to one of the known species, has applications in many disciplines, including ecology, palaeoecology and forensic science. The model we build represents life cycle and natural variation of both shape and texture over multiple diatom species, derived automatically from photographs and/or drawings. The model can be used to automatically produce drawings of diatoms at any stage of their life cycle development. Similar drawings are traditionally used for diatom identification, and encapsulate visually salient diatom features. In this article, we describe the methods used for analysis of photographs and drawings, present our model of diatom shape and texture variation, and finish with results of identification experiments using photographs and drawings as well as a detailed evaluation.     

Loss of platinum from platinised titanium in hypochlorite cells at low electrolyte temperatures

The conditions under which platinum is lost from platinised titanium anodes during the electrolysis of dilute brine solutions have been studied. The phenomenon is explained in terms of a potential-dependent change in surface structure and it is shown that platinum loss can be avoided by control of the anode potential.     

Application of fourier transform analysis to determine transient condensation heat transfer coefficients in reactor containment experiments

The method of Fourier transform analysis is used to determine the instantaneous values of condensation heat transfer coefficient at a point within the containment vessel of a simple blowdown rig. The shape of the measured heat transfer transient appears to be similar to that of the energy outflow from the blowdown pressure vessel, and a heat transfer coefficient which varies in this way is shown to give close fit to the shape of containment pressure transient when used in a lumped parameter calculation.