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Spigarelli S.,Marche Polytechnic University | El Mehtedi M.,Marche Polytechnic University | Ciccarelli D.,Marche Polytechnic University | Bamberger M.,Technion City | And 2 more authors.
Materials Science Forum | Year: 2010

The high temperature response in torsion and creep of two extruded Mg-Zn alloys was investigated in the present study. The alloy 0 (Mg-2Zn-1Mn) was found to exhibit a lower strength than the alloy 2 (Mg-0.55Zn-0.79Mn-0.75Al-0.17Ca), even if the activation energy for creep was similar for both materials (170-180 kJ/mol). The difference in flow stress was here preliminarily attributed to the precipitation of fine Al2Ca particles. © (2010) Trans Tech Publications.

Lai L.,Worcester Polytechnic Institute | Liang Y.,Syracuse University | Shitz S.S.,Technion City
2013 IEEE/CIC International Conference on Communications in China, ICCC 2013 | Year: 2013

In this paper, the sum capacity of the Poisson Z-interference channel that models optical communication systems with multiple transceivers is investigated. First, the capacity region of the Poisson Z-interference channel is shown to remain the same if we approximate the Poisson Z-interference channel with a discrete time memoryless binary input binary output Z-interference channel. Second, building on this result, the sum capacity of the Poisson Z-interference channel when the cross link coefficient is either sufficiently small or sufficiently large is characterized. When the cross link coefficient is sufficiently small, the sum capacity is achieved by treating interfering signal (if any) as noise. However, unlike the Gaussian Z-interference channel, the user not experiencing the interference does not necessarily transmit at its largest possible rate to achieve the sum capacity. When the cross link coefficient is sufficiently large, the sum capacity is achieved by letting the user experiencing the interference decode both messages. © 2013 IEEE.

Harel G.,Technion City | Bamberger M.,Technion City | Rami Y.,Alubin Ltd. | Spigarelli S.,Marche Polytechnic University | And 2 more authors.
Materials Science Forum | Year: 2010

The market share of wrought Magnesium products such as structural and functional components is recently increasing. Extrusion at elevated temperatures is used to produce reliable plastic deformation, since magnesium alloys have limited ductility at room temperature. In order to produce sound extruded products, high quality billets are required. Understanding the influence of direct chill casting conditions on the production properties such as quality, safety, workability and microstructure have a profound importance. Comprehensive computer simulations were used in order to model the casting so that process parameters can be identified and controlled, resulting in significant benefits. The aim of modeling is to provide temperature profiles for a more accurate solidification analysis, predict the solidification time and the effect of cooling on the solidification. The experimental study included castings of several Magnesium alloys, each with 7 (seven) thermocouples that were submerged into the billet. Verification of the simulations was carried out based on the data collected. Complimentary work was conducted on microstructure analysis in as cast and as-extruded states. © (2010) Trans Tech Publications.

Filin S.,Technion City | Baruch A.,Technion City
Photogrammetric Engineering and Remote Sensing | Year: 2010

Airborne laser scanning technology is primarily perceived as a means for gathering detailed three-dimensional information about the surface and objects on it. The dense 3D data contain information about surface features and geohazards, some of which are of subtle form. Geohazards are usually embedded within the terrain, and scarcely form distinct shape-transition to their surroundings; therefore their detection is challenging. We address in this paper detection of subtle terrain features and demonstrate it on collapse sinkholes. Collapse sinkholes are surface depressions whose formation has severe effect on the environment and on regional development. We present an autonomous model for their extraction and characterization. Sinkholes within the studied regions appear in various size, forms, from their embryonic to a well developed formation. The level of sinkhole detection is high, and as demonstrated, the model performs well under varying landforms and surface texture, with little influence on the correctness of the extracted sinkholes. As the results show, features of approximately 20 cm deep can be identified and separated from their surroundings in the data. © 2010 American Society tor Photogrammetry and Remote Sensing.

Mor T.,Technion City | Weinstein Y.,Technion City
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

Algorithmic cooling (AC) of spins applies entropy manipulation algorithms in open spin systems in order to cool spins far beyond Shannon's entropy bound. Algorithmic cooling of nuclear spins was demonstrated experimentally and may contribute to nuclear magnetic resonance spectroscopy. Several cooling algorithms were suggested in recent years, including practicable algorithmic cooling (PAC) and exhaustive AC. Practicable algorithms have simple implementations, yet their level of cooling is far from optimal; exhaustive algorithms, on the other hand, cool much better, and some even reach (asymptotically) an optimal level of cooling, but they are not practicable. We introduce here semioptimal practicable AC (SOPAC), wherein a few cycles (typically two to six) are performed at each recursive level. Two classes of SOPAC algorithms are proposed and analyzed. Both attain cooling levels significantly better than PAC and are much more efficient than the exhaustive algorithms. These algorithms are shown to bridge the gap between PAC and exhaustive AC. In addition, we calculated the number of spins required by SOPAC in order to purify qubits for quantum computation. As few as 12 and 7 spins are required (in an ideal scenario) to yield a mildly pure spin (60% polarized) from initial polarizations of 1% and 10%, respectively. In the latter case, about five more spins are sufficient to produce a highly pure spin (99.99% polarized), which could be relevant for fault-tolerant quantum computing. © 2011 American Physical Society.

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