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A caustic is the envelope of light rays reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface. A familiar example of optical caustics is the bright line seen in a coffee cup on a bright sunny day. Here the caustic is formed by the envelope of the light rays reflected by the curved surface of the coffee cup. Caustics are formed in an anisotropic media because the direction of the group velocity and the phase velocity or the wave vector does not coincide. New theoretical work shows the existence of spin wave caustics in nanoscale ferrites, ferromagnetic and antiferromagnetic materials. Based on their theoretical results, the researchers have proposed a new device called a high frequency 'router'.
Jan 31st, 2011
Patterns of news coverage on nanotechnology are developing in ways that mirror issue cycles for previous technologies, including agricultural biotechnology. In particular, early coverage of nanotechnology was dominated by a general optimism about the scientific potential and economic impacts of this new technology. This is in part related to the fact that a sizeable proportion of nanotechnology news coverage - at least in newspapers - continues to be provided by a handful of science journalists and business writers. This is an initial draft of an article that what will eventually become a chapter on public attitudes toward nanotechnology in a new book on risk communication and public perception of nanotechnology. It's meant to be a current update and comprehensive overview of what we know (and don't know) at this point.
Jan 24th, 2011
At the nanoscale, the properties of materials - mechanical, electrical, thermal, optical - often differ significantly from their bulk behavior. And while nanostructured and nanoengineered products are appearing in the marketplace, researchers are still trying to understand all aspects of materials properties of nanostructures and how they can be modified and controlled. Vacancies (also called Schottky defect) play a major role in the electrical and thermal transport as well as the mechanical behavior of materials. A vacancy is the simplest defect which can be created in a material - it corresponds to a lack of an atom in the lattice. New theoretical work calculates the size effect on the vacancy formation energy, the vacancy formation entropy and the vacancy concentration into nanomaterials through a top-down approach by using classical thermodynamics.
Jan 18th, 2011
Self-cleaning, water and dirt-repellent coatings have differing properties, functional principles and manufacturing processes. Self-cleaning of the 'Lotus Effect' type has its basis in chemical-physical principles - these surfaces are characterised by a special roughness and are strongly water-repellent; in the ideal case, rain is sufficient for cleaning. 'Easy-to-Clean' materials, in contrast, have a particularly flat surface, which is both water and dirt-repellent on the basis of chemical aspects. Although the amount of mechanical cleaning may be reduced, they are not self-cleaning. A third form of self-cleaning is that based on photo catalysis by nano titanium dioxide. On such surfaces UV radiation produces oxygen radicals that decompose organic material, which in turn is removed in the rain by a water film.
Jan 11th, 2011
The OECD has just published a 111-page book on nanotechnology business that attempts to provide comprehensive, internationally comparable information on how different types of companies are affected by nanotechnology, how they use it in their innovative activities, how they acquire or develop relevant competences, as well as on the specific commercialization challenges they face. It also addresses the different role that new and small as well as larger companies will play in the commercialization of nanotechnology.The case studies provide qualitative insights into the commercialization of nanotechnology from the viewpoint of companies and thus complement studies which have relied primarily on publication and patent data or statistical surveys.
Jan 10th, 2011
Global warming, caused by a build-up of greenhouse gases, in particular carbon dioxide, in the atmosphere, has led to numerous proposals on how to capture and store CO2 in order to mitigate the damaging emissions from fossil fuels. Today we take a look at carbon sequestration and subsequent storage in geological formations (geosequestration) - a proposal that is already being tested on a large scale. The idea behind coal-bed geosequestration is that you inject a huge amount of carbon dioxide into deep unmined coal seams. Due to strong adsorption forces, the carbon dioxide will be adsorbed in coal. It will not be desorbed and gradually transform to solid rocks. Moreover the technology is already developed and in use for oil and gas mining. However, the fundamental problem is so-called adsorption-induced deformation of coal or any other porous material.
Nov 30th, 2010
Since 2009, NT-MDT Co. has been holding a contest of scientific art images obtained by atomic force microscopes (AFM). Each month, researchers from around the world submit their AFM scans to the dedicated ProIMAGE contest site where they are then subject to online voting by site visitors. According to NT-MDT, a simple gender analysis of monthly winners shows that a) the percentage of women has been rising for two years, and b) women attract more votes originating from social networks. Of course, these observations are more trivia than hard scientific facts. Nevertheless, they appear to reveal a phenomenon of higher online communication skills among female scientists. It remains to be seen to what degree social networks a la Facebook and LinkedIn will change the way the scientific community interacts and communicates.
Nov 23rd, 2010
The automotive sector is a major consumer of material technologies - and nanotechnologies promise to improve the performance of existing technologies significantly. Applications range from already existing - paint quality, fuel cells, batteries, wear-resistant tires, lighter but stronger materials, ultra-thin anti-glare layers for windows and mirrors - to the futuristic - energy-harvesting bodywork, fully self-repairing paint, switchable colors, shape-shifting skin. The basic trends that nanotechnology enables for the automobile are: lighter but stronger materials; improved engine efficiency and fuel consumption for gasoline-powered cars; reduced environmental impact from hydrogen and fuel cell-powered cars; improved and miniaturized electronic systems; and better economies. This article provides an overview of a large number of efforts and applications involving nanotechnologies in the automotive industry.
Nov 12th, 2010