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Ostrava, Czech Republic

Parik P.,University of Pardubice | Jansa J.,Research Institute for Organic Syntheses VUOS | Holesova S.,Nanotechnology Center | Marek A.,Czech Institute of Organic Chemistry And Biochemistry | Klimesova V.,Charles University
Journal of Heterocyclic Chemistry

Reactivity of 2-(4-hydroxyphenyl)-1H-imidazoline and 2-(4-hydroxyphenyl)- 1H-imidazole toward substituted phenyl isocyanates was studied. When mentioned imidazoline was treated with 2.5 equiv of substituted phenyl isocyanate, three N,O-dicarboxamides were prepared (substituents are H, 4-NO2, and 4-CH3). Subsequently, N,O-diacetylated 2-(4-hydroxyphenyl)-1H- imidazoline was prepared and selective deprotection method was developed for preparation of 1-acetyl-2-(4-hydroxyphenyl)-1H-imidazoline using diethylamine in acetone. Six carbamates derived from this imidazoline were then prepared using 1.1 equiv of substituted phenyl isocyanates (substituents are H, 4-CH 3, 4-OCH3, 4-NO2, 4-CN, and 3-CF3). Finally, two carbamates were prepared from 2-(4-hydroxyphenyl)-1H-imidazole (substituents are 4-NO2 and 4-CN). No reactivity to imidazole ring was observed in this case. Eight derivatives were subjected to antimycobacterial screening. Concurrently, reactivity of 2-(2-aminophenyl)- and 2-(2-hydroxyphenyl)-1H-imidazole toward aliphatic and aromatic isocyanates was studied. Eight ureas were prepared using equivalent mixture of 2-(2-aminophenyl)-1H-imidazole and isocyanate (Et, Pr, isoPr, terc-Bu, Cy, Ph, 4-CH3C6H4, 4-CNC6H4). Similar attempts to obtain related carbamates from 2-(2-hydroxyphenyl)-1H- imidazole lead only to three substituted phenyl carbamates (substituents are 4-CH3, 4-NO2, and 4-CN). In both cases, no reactivity to imidazole ring was observed again. © 2013 HeteroCorporation. Source

Rieder M.,Nanotechnology Center
Mineralogical Magazine

Data based on end-member formulae of 4872 minerals (4975 entries) were subjected to numerical treatment and plotting. Most conspicuous among the findings is the hydration trend that spans the whole mineralogical system - something that may be related to the geological history of mineral formation on Earth. Interesting negative relationships were confirmed for pairs O and F, O and Cl, and Al and Si, while the O vs. S graph documents the dual nature of the behaviour of sulfur. Determinations of Al and Si have the potential of alarming the analyst that his phase might contain hydrogen. The dataset available also permitted the plotting of histograms that illustrate the preferred concentration distribution of individual elements throughout the mineral kingdom. © 2016 The Mineralogical Society. Source

Rieder M.,Nanotechnology Center
European Journal of Mineralogy

All minerals in the mineralogical system can be projected onto a plane using four pairs of functions: each pair consists of the InfEnt function and one of four Qual functions. InfEnt is the information entropy (a function of the stoichiometry of a mineral formula), and Qual-1... Qual-4 are different but related functions of the atomic numbers of the elements present. The InfEnt vs. Qual plots for mineral groups or for the whole system offer a new insight into the behavior of chemical elements in minerals. They also permit plotting of scalar physical properties as a third dimension. The InfEnt and Qual data for 4872 mineral end-members are stored in a file that can be searched and used to identify unidentified or new mineral phases. © 2014 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart. Source

Kubonova L.,Institute of Environmental Technology | Fridrichova D.,Institute of Environmental Technology | Fridrichova D.,Energy Units for Utilization of Non Traditional Energy Sources | Peikertova P.,Institute of Environmental Technology | And 7 more authors.
NANOCON 2015 - 7th International Conference on Nanomaterials - Research and Application, Conference Proceedings

Three different ordered mesoporous silica materials, such as MCM-41, Al containing MCM-41 (mass ratio Si/Al = 10) and SBA-15, were prepared. In a next step, cobalt (5-8 wt%) as an active metal for redox reactions, was introduced by the impregnation. The prepared catalysts were characterized by AAS, EDX, N2 physisorption, XRD, DR UV-Vis spectroscopy, Raman spectroscopy, TPR-H2 and their catalytic properties were evaluated for N2O decomposition and reduction. The catalysts showed poor activity in N2O decomposition while the use of reducing agent (carbon monoxide) was beneficial for their catalytic activities. The lowest catalytic activity showed Co/Al-MCM indicating that the aggregated CoxOy species present in this catalyst were inactive and not beneficial for the catalytic activity. Source

Crawled News Article
Site: http://www.nanotech-now.com/

Abstract: Dynamic optoelectric trapping and deposition of multiwalled carbon nanotubes Avanish Mishra1, Katherine Clayton1, Vanessa Velasco2, Stuart J. Williams2 and Steven T. Wereley1 1Birck Nanotechnology Center, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA and 2Department of Mechanical Engineering, University of Louisville, KY 40292, USA. Correspondence: Steven T. Wereley In the path toward the realization of carbon nanotube (CNT)-driven electronics and sensors, the ability to precisely position CNTs at well-defined locations remains a significant roadblock. Highly complex CNT-based bottom–up structures can be synthesized if there is a method to accurately trap and place these nanotubes. In this study, we demonstrate that the rapid electrokinetic patterning (REP) technique can accomplish these tasks. By using laser-induced alternating current (AC) electrothermal flow and particle–electrode forces, REP can collect and maneuver a wide range of vertically aligned multiwalled CNTs (from a single nanotube to over 100 nanotubes) on an electrode surface. In addition, these trapped nanotubes can be electrophoretically deposited at any desired location onto the electrode surface. Apart from active control of the position of these deposited nanotubes, the number of CNTs in a REP trap can also be dynamically tuned by changing the AC frequency or by adjusting the concentration of the dispersed nanotubes. On the basis of a calculation of the stiffness of the REP trap, we found an upper limit of the manipulation speed, beyond which CNTs fall out of the REP trap. This peak manipulation speed is found to be dependent on the electrothermal flow velocity, which can be varied by changing the strength of the AC electric field. A system that uses a laser and electrical current to precisely position and align carbon nanotubes represents a potential new tool for creating electronic devices out of the tiny fibers. Because carbon nanotubes have unique thermal and electrical properties, they may have future applications in electronic cooling and as devices in microchips, sensors and circuits. Being able to orient the carbon nanotubes in the same direction and precisely position them could allow these nanostructures to be used in such applications. However, it is difficult to manipulate something so small that thousands of them would fit within the diameter of a single strand of hair, said Steven T. Wereley, a professor of mechanical engineering at Purdue University. "One of the things we can do with this technique is assemble carbon nanotubes, put them where we want and make them into complicated structures," he said. New findings from research led by Purdue doctoral student Avanish Mishra are detailed in a paper that has appeared online March 24 in the journal Microsystems and Nanoengineering, published by the Nature Publishing Group. The technique, called rapid electrokinetic patterning (REP), uses two parallel electrodes made of indium tin oxide, a transparent and electrically conductive material. The nanotubes are arranged randomly while suspended in deionized water. Applying an electric field causes them to orient vertically. Then an infrared laser heats the fluid, producing a doughnut-shaped vortex of circulating liquid between the two electrodes. This vortex enables the researchers to move the nanotubes and reposition them. "When we apply the electric field, they are immediately oriented vertically, and then when we apply the laser, it starts a vortex, that sweeps them into little nanotube forests," Wereley said. The research paper was authored by Mishra; Purdue graduate student Katherine Clayton; University of Louisville student Vanessa Velasco; Stuart J. Williams, an assistant professor of mechanical engineering at the University of Louisville and director of the Integrated Microfluidic Systems Laboratory; and Wereley. Williams is a former doctoral student at Purdue. The technique overcomes limitations of other methods for manipulating particles measured on the scale of nanometers, or billionths of a meter. In this study, the procedure was used for multiwalled carbon nanotubes, which are rolled-up ultrathin sheets of carbon called graphene. However, according to the researchers, using this technique other nanoparticles such as nanowires and nanorods can be similarly positioned and fixed in vertical orientation. The researchers have received a U.S. patent on the system. The experimental work was performed at the Birck Nanotechnology Center in Purdue's Discovery Park. Future research will explore using the technique to create devices. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

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