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Taboão da Serra, Brazil

Timber-frame and solid timber construction methods have recently found their way not just into prefabricated house construction but also, to an ever greater extent, multi-family dwellings. Currently used light weight structures have little sound insulation in the lower frequency range and particularly in the range below 100 Hz. Recent literature has consistently pointed out the importance of considering this frequency range in acoustic evaluations, even though there are few data available with regard to measuring accuracy and reproducibility. For the inter-laboratory test both a vertically laminated wooden floor and a wooden joist floor were chosen since the two timber construction methods vary in terms of the airborne and impact sound insulation characteristics. In comparison to other inter-laboratory tests all results show the expected values for the repeatability value r and the reproducibility value R for the traditional frequency range of 100 Hz to 3150 Hz. The results regarding the spectrum adaptation terms show that they are distinctly affected by the frequency range below 100 Hz. If this frequency range is given greater weight, the result is adversely high values for the repeatability value r and, even worse, the reproducibility value R. Source

Roozen N.B.,Catholic University of Leuven | Muellner H.,Federal Institute of Technology | Labelle L.,Catholic University of Leuven | Rychtarikova M.,Catholic University of Leuven | And 2 more authors.
Journal of Sound and Vibration | Year: 2015

Structural details and workmanship can cause considerable differences in sound insulation properties of timber frame partitions. In this study, the influence of panel fastening is investigated experimentally by means of standardized sound reduction index measurements, supported by detailed scanning laser Doppler vibrometry. In particular the effect of the number of screws used to fasten the panels to the studs, and the tightness of the screws, is studied using seven different configurations of lightweight timber frame building elements. In the frequency range from 300 to 4000 Hz, differences in the weighted sound reduction index RW as large as 10 dB were measured, suggesting that the method of fastening can have a large impact on the acoustic performance of building elements. Using the measured vibrational responses of the element, its acoustic radiation efficiency was computed numerically by means of a Rayleigh integral. The increased radiation efficiency partly explains the reduced sound reduction index. Loosening the screws, or reducing the number of screws, lowers the radiation efficiency, and significantly increases the sound reduction index of the partition. © 2015 Elsevier Ltd. All rights reserved. Source

Vargas R.,Sao Paulo State University | Mathias-Neto W.P.,Sao Paulo State University | Da Silva L.G.W.,Federal Institute of Technology | Mantovani J.R.S.,Sao Paulo State University
2015 IEEE PES Innovative Smart Grid Technologies Latin America, ISGT LATAM 2015 | Year: 2015

This paper presents a new technical approach based on mixed integer nonlinear mathematical formulation for the automatic restoration problem of distribution networks with distributed generation (DG), using node-depth encoding (NDE) and tabu search (TS) metaheuristic. The mathematical model considers the possibility of DG isolated operation and two principal objectives of restoration problem, that are to minimize number of consumers without energy supply outside the affected area, and to minimize the number of required switching. This methodology provides a switching logic sequence, which guaranties to attend operational aspects of distribution grids avoiding creating loops or generating short-circuits throughout the manually or automatic switching process. Finally, results of the proposed methodology for a 135 bus-system are presented in single-faulted and multiple-faulted scenarios, showing the effectiveness of the algorithm. © 2015 IEEE. Source

Joy J.,TATA Elxsi | Joy J.,Federal Institute of Technology | Raghu A.,TATA Elxsi
Lecture Notes in Electrical Engineering | Year: 2013

The need for better technologies and features prompted vehicle manufactures to use specialized hardware devices in vehicle. Improved functionality as always comes with increased cost. Manufacturers look at giving better functionality at reduced cost. The driver information and entertainment features in the vehicle are closely in line with consumer electronics, which is growing at a very fast rate than the vehicle. It is always better to provide the connectivity to the consumer devices. One good alternative in In-vehicle infotainment is using a tablet in place of traditional inbuilt mechanism. The tablet will provide the technology advancements in the area of entertainment, connectivity and a development environment, on top of which the OEM can trademark their infotainment system. Present embedded systems on vehicles are developed to address the safety and not security requirements. But connecting third party equipment to the vehicle system causes serious security concerns. We need a full proof security mechanism for connecting tablets to our vehicle network. This integration could also pave way for a new business model in the automotive industry, something on the lines of "App Stores". Any application from the OEM store can be downloaded and installed in the vehicle. This paper proposes architecture for secure tablet integration in automotive network. © 2013 Springer-Verlag. Source

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

DGIST announced on Tuesday August 2, 2016 that Professor Choi Hong-soo's research team from the Department of Robotics Engineering developed ciliary microrobots with high propulsion efficiency in highly-viscous fluid environments in the human body such as blood by mimicking the movement of paramecia's cilia. Professor Choi's research team succeeded in fabricating the world's first ciliary microrobots utilizing ultra-fine three-dimensional processing technology and asymmetric magnetic drive technology by applying microorganism's ciliary movement, which thus far had only been theorized but never put into practice. Microfluidic environments in which microorganisms move include highly viscous environments like the human body's internal fluids; thus, in a macro environment, it is difficult to create propulsion with swimming-based mechanisms such as inertia-based symmetrical rowing like that used by large animals such as humans. As such, microorganisms moving in highly-viscous environments utilize various other propulsion techniques such as spiral drive motion, progressive wave motion, ciliary asymmetric reciprocating motion, and the like. Microrobots that use propulsion mechanisms such as spiral drive motion and progressive wave motion were first realized and implemented at the Zurich Federal Institute of Technology, Switzerland; University of Twente, Netherlands; and Harvard University, USA. However, the development of microrobots that move utilizing ciliary motion has thus far been absent due to the difficulty of producing a microstructure with a large number of cilia as well as with asymmetrical drive. Professor Choi's research team has produced a ciliary microrobot with nickel and titanium coating on top of photo-curable polymer material, using three-dimensional laser process technology and precise metal coating techniques. In addition, the team verified that the speed and propulsion efficiency of their newly-developed microrobots were much higher than those of existing conventional microrobots moving under magnetic attraction drive after measuring the ciliary microrobots' movement utilizing asymmetrical magnetic actuation technology. The maximum speed of ciliary microrobots with a length of 220 micrometers and a height of 60 micrometers is 340 micrometers per second, thus they can move at least 8.6 times faster and as much as 25.8 times faster than conventional microrobots moving under magnetic attraction drive. In comparison to previously developed microrobots, Professor Choi's ciliary microrobots are expected to deliver higher amounts of chemicals and cells to target areas in the highly viscous body environment thanks to their ability to freely change direction and to move in an 80 micrometer-diameter sphere to the target point shown in the experiment using the magnetic field. Professor Choi from DGIST's Department of Robotics Engineering said, "With precise three-dimensional fabrication techniques and magnetic control technology, my team has developed microrobots mimicking cilia's asymmetric reciprocation movement, which has been never realized so far. We'll continually strive to study and experiment on microrobots that can efficiently move and operate in the human body, so that they can be utilized in chemical and cell delivery as well as in non-invasive surgery." Explore further: 'Brobots': Sperm-inspired robots controlled by magnetic fields may be useful for drug delivery, IVF, cell sorting More information: Sangwon Kim et al. Fabrication and Manipulation of Ciliary Microrobots with Non-reciprocal Magnetic Actuation, Scientific Reports (2016). DOI: 10.1038/srep30713

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