The use of X-ray diffraction, microscopy, and magnetic measurements for analysing microstructural features of a duplex stainless steel

X-ray diffraction, light optical microscopy, and magnetization saturation measurements were employed to analyse the microstructural features of a UNS S31803 duplex stainless steel modified by high-temperature treatments. The samples were heated to 1300 °C and cooled by different ways to produce five different microstructures. Solution treatments at 1000 °C were also employed to produce another five conditions. Three methods were employed to determine the austenite/ferrite proportions. X-ray diffraction gave higher austenite values than the other methods, due to the influence of texture, but can be successfully used to determine the microstrain level in each phase. Magnetic saturation measurement is a very simple and precise method for quantification of austenite and ferrite volume fractions in samples that were fast-cooled and slow-cooled. Light microscopy can give a fast and precise measurement of the phase proportions and reveals important features related to the morphology of the phases, but in the samples where the austenite content is low, quantification becomes difficult and imprecise.     

Hepatic hemangioma. Analysis of 103 cases. Clinical considerations and imaging methods

Hemangiomas are the most common benign vascular tumor found in the liver. In this study, 103 cases of hepatic hemangiomas were analysed in a retrospective manner. Image aspects such as those seen in ultrassonography, computed tomography, nuclear magnetic resonance and arteriography are discussed. The incidence was higher amongst the female sex, between individuals from 40 to 60 years old, which presented predominantly without symptoms (66%) and localized mainly in the right hepatic lobe (74%). The meaning of those aspects, when adopted, permits the clinicians to differentiate benign from malignant nodular lesions in the liver.     

On the Internet: Turbulence and 1001 Nights of Networked Performance

In this issue, Art Beat looks at networked performance, featuring Turbulence, a net art portal. Turbulence's Helen Thorington and Jo-Ann Green discuss their blog, Networked_Performance, which provides an extensive archive of networked performances. We also profile performance artist Barbara Campbell's 1,001 Nights Cast, a durational networked performance project. Multimedia researchers interested in Web 2.0 might want to help develop a template or standard that lets performance artists share and search their work on the Web. Such work could also ensure that certain software, when it fades away, is translatable or included in new versions of software so that viewing art isn't contingent on outdated file formats.     

A novel biomagnetic method to study gastric antral contractions

A novel non-invasive method to study the motion associated with gastric antral contractions is discussed. The method is based on magnetic flux changes detected by an a.c. biosusceptometer, produced by a magnetic test meal within the stomach. Measurements are made at the surface of the torso and are easy to perform. Simultaneous measurements were made with electrogastrography and scintigraphy showing remarkable coincidence. The effect of a drug on the amplitude of antral contractions was also assayed with the new method.     

Rheological characterization of egg yolk processed by spray-drying and lipid-cholesterol extraction with carbon dioxide

The present work studies the rheological properties of avian egg yolks processed by spray-drying and by lipid-cholesterol extraction with CO₂ under near-critical conditions. The results have been compared with those obtained from native egg products in order to analyze the effect of processing on the microstructure and rheological properties of egg yolks. The rheological study included linear viscoelasticity measurements by means of dynamic oscillatory shear and creep tests, which provided information about the unperturbed structure of the material, as well as steady-state flow measurements. The thermal denaturation of proteins, which was produced during the spray-drying of egg yolk, was responsible for the dramatic change from fluid to gel-like behavior. The thermal denaturation of proteins promotes the formation of a gel-like network, which may be attributed to exposure of internal hydrophobic groups that favor protein aggregation. Lipid (and cholesterol) extraction from yolk increased the viscoelasticity functions and flow properties due to the increased protein concentration.     

Analytic model for the post-breakdown conductance of sub-5-nm SiO/sub 2/ gate oxides

A new model for the post-breakdown conductance of ultrathin gate oxides based on the generalized diode equation is presented. The model is expressed in terms of the Lambert W function, that is, the inverse of the function w/spl rarr/we/sup w/. We show that this alternative formulation improves a previous one, the quantum point contact model, especially in the low bias range, where the role played by the semiconductor electrodes cannot be overlooked. The practical implementation of the proposed equations is discussed.     

Optimised immobilisation of microbial lipase on hydrous niobium oxide

The aim of this work was to establish appropriate conditions for immobilising Candida rugosa lipase on a low‐cost inorganic matrix, hydrous niobium oxide, using a multivariate statistical approach. A 2³ full factorial design was employed to determine the effects of support activation with glutaraldehyde (concentration 2.5–4.5%, pH 7–10) and lipase loading (200‐700 U g^?1 matrix) on the hydrolytic and synthetic activities of the immobilised derivatives. From the results the following conditions were established: lipase loading of 450 U g^?1 matrix and niobium oxide activation with glutaraldehyde at a concentration of 2.5% and pH 8. Under these conditions, high activity recovery (47.21%) and esterification yield (86.90%) were attained. The results also show that hydrous niobium oxide can be a valid alternative to replace high‐cost, commercially available inorganic matrices such as controlled pore silica. Copyright © 2006 Society of Chemical Industry