Other materials science stories that may be of interestPublished on July 9th, 2012 | By: firstname.lastname@example.org
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A newly published article in Physical Review Letters eliminates one of the top unsolved theoretical problems in chemical physics as ranked by the National Research Council in 1995. Scientists now can more accurately predict the dynamic behavior of electrons in atoms and molecules in chemical reactions that govern a wide range of phenomena, including the fuel efficiency of combustion engines and the depletion of the atmospheric ozone. The paper by David Mazziotti, professor in chemistry at the University of Chicago, solves what specialists call the “N-representability problem.” Mazziotti’s goal was to find a way to calculate the properties of many-electron systems via a two-electron technique, where the two electrons represent the other electrons in the system. “The two-electron models provide a platform for exploring a whole range of chemistry and physics,” Mazziotti says. “If you are calculating, let’s say, the water molecule, which has 10 electrons, your two-electron model has only two of the 10 electrons . But the probability for finding those two electrons must be consistent with the other eight electrons in the real system.”
Researchers at the McCormick School of Engineering, working with a team of scientists from the US and abroad, have recently developed a design that allows electronics to bend and stretch to more than 200 percent their original size, four times greater than is possible with today’s technology. The key is a combination of a porous polymer and liquid metal. “With current technology, electronics are able to stretch a small amount, but many potential applications require a device to stretch like a rubber band,” said Yonggang Huang, Joseph Cummings Professor of Civil and Environmental Engineering and Mechanical Engineering. One challenge facing these researchers has been overcoming a loss of conductivity in stretchable electronics. Huang’s team has found a way to overcome these challenges. First, they created a highly porous three-dimensional structure using a polymer material, poly(dimethylsiloxane), that can stretch to three times its original size. Then they placed a liquid metal (EGaIn) inside the pores, allowing electricity to flow consistently even when the material is excessively stretched.
(Nature Nanotechnology) In atomic force microscopy a cantilever with a sharp tip attached to it is scanned over the surface of a sample, and information about the surface is extracted by measuring how the deflection of the cantilever—which is caused by interactions between the tip and the surface—varies with position. In the most common form of atomic force microscopy, dynamic force microscopy, the cantilever is made to vibrate at a specific frequency, and the deflection of the tip is measured at this frequency. But the motion of the cantilever is highly nonlinear, and in conventional dynamic force microscopy, information about the sample that is encoded in the deflection at frequencies other than the excitation frequency is irreversibly lost. Multifrequency force microscopy involves the excitation and/or detection of the deflection at two or more frequencies, and it has the potential to overcome limitations in the spatial resolution and acquisition times of conventional force microscopes. Here we review the development of five different modes of multifrequency force microscopy and examine its application in studies of proteins, the imaging of vibrating nanostructures, measurements of ion diffusion and subsurface imaging in cells.
(Gizmag) Researchers at Aalto University in Finland have discovered a novel way to write and present information using only water and air. They used the water-repelling properties of the lotus leaf as inspiration for an experiment with a superhydrophobic, dual-scale surface that allows the writing, erasing, rewriting and storing of optically displayed information in plastrons related to different length scales. The research was carried out in partnership with the Nokia Research Center and University of Cambridge and was led by Robin Ras at Aalto University. The surface was placed inside a container filled with water and featured microposts of ten micrometers in size and tiny nanofilaments grown on the posts. This type of two-level surface allows the air layer to exist in two different shapes that correspond to the two size scales. Using a nozzle, the scientists succeeded in switching between dry and wet states by creating excessive or insufficient pressure in the water in order to change the air layer to either state. The switching only involves a change in the shape of the air layer while nothing actually happens to the solid surface itself, allowing them to write shapes on the surface underwater by making use of the contrast between the states. It can be done with precision, pixel-by-pixel. The whole “screen” then can be deleted by removing it from water. The surface comes out dry, with no sign of writing on its surface.
Iran’s Nanotechnology Initiative Council reports that Iranian and Italian researchers succeeded in the synthesis of lithium-mica nanocrystal glass-ceramic through a new sol-gel method. The synthesized material has certain advantages like appropriate optical properties and can be machined. The research group synthesized lithium-mica nanocrystal glass-ceramic through sol-gel methods by using raw materials such as Mg(NO3)2.6H2O, LiNO3, aluminium isoperoxide, NH4F and silica. No report has so far been observed for the synthesis of this compound through the said method. Analysis results showed that the crystals synthesized through the new sol-gel method were smaller than the crystals produced in the ordinary methods. By using the model suggested by Marotta, the researchers calculated the crystalline activation energy and Avrami parameter, and they explained the growth of the crystals by using the same method. Since the crystals are distributed homogeneously within the glassy phase in sol-gel method, the use of this method results in the homogeneity of the glass-ceramic structure, which is mandatory for the machining.
(University World News) Mohamed Morsi has become the fifth president of Egypt after winning 51.7% of votes in a run-off election, making him the first university professor to rule a country in the Arab world. His election is of considerable significance to higher education. Morsi was born in August 1951 in Sharqiya province. He received a bachelor of engineering degree from Cairo University in 1975, and a masters in metallurgy from the same university in 1978. Then in 1982, he obtained a PhD in engineering from the University of Southern California in the US. He worked as a lecturer and a teacher assistant in the faculty of engineering at Cairo University, and at the University of Southern California. He also worked as an assistant professor at the University of North Ridge in California between 1982 and 1985. From 1985 until 2010 Morsi was a professor and head of materials engineering at Zagazig University in the Egyptian city of the same name. He was elected a member of the faculty staff club at Zagazig. According to his election programme, he plans gradually to increase spending on research and development to 2.5 percent of gross domestic product, to link research institutes to industry, and to promote the protection of intellectual property.
(GigaOm) Hadoop is a big machine. Once you get it up to speed it’s great at crunching your data. Get the disks spinning forward as fast as you can. However, each time you want to analyze the data (say after adding, modifying or deleting data) you have to stream over the entire dataset. If your dataset is always growing, this means your analysis time also grows without bound. So, how does Google manage to make its search results increasingly real-time? By displacing Google MapReduce in favor of an incremental processing engine called Percolator. By dealing only with new, modified, or deleted documents and using secondary indices to efficiently catalog and query the resulting output, Google was able to dramatically decrease the time to value. Coming from the Large Hadron Collider (an ever-growing big data corpus), this topic is near and dear to my heart. Some datasets simply never stop growing.
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