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Kiev, Ukraine

Zgalat-Lozynskyy O.,IPMS | Herrmann M.,IKTS | Ragulya A.,IPMS | Andrzejczuk M.,WUT | Polotai A.,MRA Laboratories Inc
Archives of Metallurgy and Materials | Year: 2012

Consolidation of commercially available titanium nitride nanostructured powder as well as nanocomposite powders in the Si 3N 4-TiN and TiN-TiB 2 systems have been performed by Spark Plasma Sintering (SPS) in the temperature range from 1200°C to 1550 °C. The effect of non-linear heating and loading regimes on high melting point nanocomposites consolidation has been investigated. Source

Zgalat-Lozynskyy O.,IPMS | Andrzejczuk M.,WUT | Varchenko V.,IPMS | Herrmann M.,IKTS | And 2 more authors.
Materials Science and Engineering A | Year: 2014

A superplastic deformation of pre-sintered Si3N4-based nanocrystalline ceramics and Si3N4 nano-whisker reinforced composites has been investigated. Superplastic deformation tests have been carried out in the temperature range from 1500 to 1600°C under 56kN compression in nitrogen. During the tests, all nano-composites exhibited high rates of deformation (1.6-5.4×10-3s-1) corresponding to high activation energy in the range of 538-699kJ/mol. The composites enhanced by Si3N4 nano-whiskers exhibited the formation of anisotropic microstructure with anisotropic mechanical properties. The highest Vickers hardness ~19GPa and lowest coefficient of dry wear 0.39 was exhibited by the TiN-Si3N4 nano-composite. © 2014 Elsevier B.V. Source

Zgalat-Lozynskyy O.,IPMS | Varchenko V.,IPMS | Tischenko N.,IPMS | Ragulya A.,IPMS | And 2 more authors.
Tribology International | Year: 2015

A comprehensive study was performed to evaluate tribological performances of newly developed Si3N4-based nanocomposites enhanced by either Si3N4 nanowhiskers or TiN nanoparticles and consolidated via a Rate Controlled Sintering technique. A wear resistance of Si3N4-based nanocomposites was studied under dry sliding conditions using bearing steel, hard alloy, and Si3N4-based nanocomposites counterparts. The Si3N4-TiN nanocomposites exhibited low sliding friction coefficient o 0.35 with hard alloy and < 0.25 with Si3N4-based nanocomposite. A specific wear rate for the investigated nanocomposites was estimated to be in the range from 2 · 10-7 mm3/N m to 5 · 10-8 mm3/N m. A chemical resistance of the Si3N4-TiN nanocomposite was investigated in aggressive mediums, such as acids and bases at elevated temperatures. © 2015 Elsevier Ltd. All rights reserved. Source

News Article
Site: http://phys.org/technology-news/

Large public building complexes, such as exhibition halls, airports, shopping centers or museums, as well as hospitals and public authority buildings are sometimes like a maze. Arrows, maps and signs are supposed to make it clearer. But right when you enter the building for the first time, it is often very laborious and complicated to follow them through the maze of corridors, hallways, rooms and floors. Classic GPS-based navigation apps do not work in enclosed spaces, because the satellite signals are sometimes significantly disrupted by walls and ceilings. Researchers at the Fraunhofer Institute for Photonic Microsystems IPMS in Dresden, Germany have found a way to use smartphones for navigation inside buildings too. For this they rely on WLAN: With local radio networks, the researchers locate smartphones indoor to within about two meters. To determine the position, the software evaluates the signal strength of the WLAN spots. The app, which was originally developed for use in hospitals, is based on the Android mobile phone operating system. When starting the app, different targets can be selected – for example, examination rooms, patient rooms, cafeterias and restrooms or mobile inventory, such as beds and wheelchairs. As with navigation devices in cars, the user sees the building plan in a two-dimensional bird's-eye view. The target and current position are marked with dots and the shortest route is shown on the map. If the user moves, so does his position point. If the destination is outside the screen or on a different floor, arrows show the way. The hospital provides the material for the desired maps. Emergency evacuation plans can often be used as a template. "We can bring any large map sharply and without any annoying delays onto every screen," says Christian Scheibner from the Department of Wireless Microsystems of the IPMS. The app receives all the necessary data from the user's server. Thanks to open interfaces, the positioning and navigation algorithms as well as the graphical representations can be installed simply and straightforwardly in customers' applications. In the apps of trade fairs organizers, for example, which often lack maps, route planning or position determination. "Hospitals have caught up considerably in terms of wireless hot spots in recent years. For example, there are more and more medical devices which are equipped with WLAN and which can be used for indoor navigation" says the hardware and software developer Scheibner. The software works in all indoor areas where WLAN is available. The navigation destinations can be linked with other information. As a result, a user in a shopping mall, for example, will find his way directly and quickly to the rack with special deals. A demo system of the app is running successfully at the IPMS. "Interested parties can try it on site at the Institute at any time," says Scheibner. The technology was developed on behalf of an infrastructure outfitter for hospitals. They are being presented at the MEDICA international trade fair in Dusseldorf from November 16 to 19, 2015. Explore further: WLAN leads the way

News Article
Site: http://phys.org/technology-news/

Scanning electron micrograph of a sample of V-like nanoscopic electrostatic drives actuator. (a) Two cuts are made with a focused ion beam after sacrificial layer releases etch. (b-e) Cross sections that detail the NED elementary actuator cell. Credit: Fraunhofer Institute for Photonic Microsystems IPMS Researchers from the Mesoscopic Actuators and Systems (MESYS) project group at Fraunhofer Institute for Photonic Microsystems IPMS have been developing novel electrostatic microactuators, so-called nanoscopic electrostatic drives (NED), for three years. Now, this highly interesting scientific approach is being introduced to the public for the first time in an article appearing in the Nature Communications journal. Prof. Dr. Harald Schenk, Director of the Fraunhofer IPMS and Professor of Micro and Nanosystems at Brandenburg Technical University Cottbus-Senftenberg (BTU), is delighted, "We are very proud of the appreciation of our work and our results being published in this prestigious professional journal. After three years of basic research, we were able to demonstrate a completely new actuatory principle." The CMOS compatible actuator class technology developed by MESYS solves fundamental problems of electrostatic actuators. Previously, deflection was very limited due to the so-called pull-in-effects and the movement of conventional actuators was restricted to approximately 33 percent of the electrode spacing. This problem has now been solved. Group Leader Holger Conrad explains, "By means of suitable lever mechanisms, deflections which are much greater than the electrode separations are now available. Therefore, nanometer-small electrode spacings can be deployed, enabling actuators to make use of the enormous force of electrostatic fields." The patented actuator class can greatly improve the performance of microsystems such as capacitive ultrasonic transducers, tilting micro-mirrors and microvalves in the future. In addition, the actuator class provides completely new design solutions for microsystems such as micropumps, MEMS loud speakers or micro positioning systems. Conrad concludes, "Our vision is to develop electrostatic actuators with extremely small gap distances for high deflections at moderate control voltages. We want to extend the developed principle to enable in-plane movement and believe that the new electrostatic bender actuators could perspectively replace or supplement piezoelectric or electrostrictive materials as well. This would then allow for RoHs-compliant bender actuators." The article was published on Nature Communications and is freely available as Open Access: Explore further: New chip provides better bioimaging performance

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