EBSD investigation of the effect of the solidification rate on the nucleation behavior of eutectic components in a hypoeutectic Al-Si-Cu alloy

This article represents a study of the influence of the solidification rate on the crystallographic orientation of eutectic components with respect to the primary ??-Al in the tested hypoeutectic alloy. Electron backscattering diffraction (EBSD) patterns were produced from the Al-Si cast specimens that were solidified with different cooling rates and prepared via ion etch polishing as a complementary method after mechanical polishing. The results indicated a strong orientation relationship between the primary ??-Al and eutectic Al phase at all cooling rates. It was also found that the silicon eutectic flakes were heterogeneously nucleated in the interdendritic eutectic liquid. The increase of the cooling rate from 2 to 80 mm/min was found to be effective in lowering the intensity of the relationship between the primary ??-Al and eutectic Al phases, and changing the misorientation angle clustering between the primary ??-Al and eutectic Si phases in the interval from 41?C60° to lower angle intervals.     

Al<Subscript>2</Subscript>O<Subscript>3</Subscript> nanoparticle reinforced Fe-based alloys synthesized by thermite reaction

It is very difficult to manufacture oxide nanoparticle strengthened alloys through the conventional casting in the gravity field or even in the space microgravity environment. A thermite reaction process was used to produce molten metal that was then solidified in a graphite mold in super gravity field caused by centrifugal force; we were able to obtain Al₂O₃ nanoparticle reinforced Fe-based alloys. The formation of Al₂O₃ nanoparticles was related to the addition of TiO₂ xerogel to the thermite mixture, and their uniform distribution in the alloy can be explained by their assembly in (Ni, Fe)Al intermetallics during solidification owing to the low interfacial energy between them.     

Real-time scan assistant for echocardiography

A real-time scan assistant (SA) for use with echocardiography is presented. The motivation is to aid nonexpert users in capturing apical 4-chamber views (A4CH) during echocardiography. The algorithm is based on a parametric multi-chamber model of the A4CH view, updated in an extended Kalman filter framework. The regional model goodness-of-fit is used to calculate a score, which is provided to the user during acquisition, together with an icon (emoticon) indicating whether the current view is acceptable or not. The SA was implemented on a commercially available scanner. A feasibility test was performed using two healthy volunteers as models and 10 medical students acting as nonexpert users. The students examined the models on two occasions, separated more than four days in time. Half of the students used the SA during the first exam and no SA at the second exam. The other half used the opposite order. The recordings were later rated by a cardiologist. A Wilcoxon signed pair rank test revealed a statistically significant improvement when using SA. Nine cases were rated as poor without using the SA. In eight (89%) of these cases, view quality improved to acceptable when the SA was used.     

Electrical and gas sensing properties of <Emphasis Type="Italic">por</Emphasis>-Si/SnO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> nanocomposite layers

The electrical characteristics and chemical reactant sensitivity of layers of heterogeneous nanocomposites based on porous silicon and nonstoichiometric tin oxide por-Si/SnO _x , fabricated by the magnetron sputtering of tin with subsequent oxidation, are studied. It is shown that, in the nanocomposite layers, a system of distributed heterojunctions (Si/SnO _x nanocrystals) forms, which determine the electrical characteristics of such structures. The sensitivity of test sensor structures based on por-Si/SnO _x nanocomposites to NO₂ is determined. A mechanism for the effect of the adsorption of NO₂ molecules on the current-voltage characteristics of the por-Si(p)/SnO _x (n) heterojunctions is suggested.     

Replacing fossil oil with fresh oil – with what and for what?

Industrial chemicals and materials are currently derived mainly from fossil‐based raw materials, which are declining in availability, increasing in price and are a major source of undesirable greenhouse gas emissions. Plant oils have the potential to provide functionally equivalent, renewable and environmentally friendly replacements for these finite fossil‐based raw materials, provided that their composition can be matched to end‐use requirements, and that they can be produced on sufficient scale to meet current and growing industrial demands. Replacement of 40% of the fossil oil used in the chemical industry with renewable plant oils, whilst ensuring that growing demand for food oils is also met, will require a trebling of global plant oil production from current levels of around 139 MT to over 400 MT annually. Realisation of this potential will rely on application of plant biotechnology to (i) tailor plant oils to have high purity (preferably >90%) of single desirable fatty acids, (ii) introduce unusual fatty acids that have specialty end‐use functionalities and (iii) increase plant oil production capacity by increased oil content in current oil crops, and conversion of other high biomass crops into oil accumulating crops. This review outlines recent progress and future challenges in each of these areas. Practical applications: The research reviewed in this paper aims to develop metabolic engineering technologies to radically increase the yield and alter the fatty acid composition of plant oils and enable the development of new and more productive oil crops that can serve as renewable sources of industrial feedstocks currently provided by non‐renewable and polluting fossil‐based resources. As a result of recent and anticipated research developments we can expect to see significant enhancements in quality and productivity of oil crops over the coming decades. This should generate the technologies needed to support increasing plant oil production into the future, hopefully of sufficient magnitude to provide a major supply of renewable plant oils for the industrial economy without encroaching on the higher priority demand for food oils. Achievement of this goal will make a significant contribution to moving to a sustainable carbon‐neutral industrial society with lower emissions of carbon dioxide to the atmosphere and reduced environmental impact as a result.