1,426 research outputs found

    Use of Engines Manufactured by SE "Zorya"-"Mashproekt" GTR&PC for Renovation of the Gas Transportation System of "Ukrtransgaz" PJSC

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    The article observes potential participation of SE "Zorya"―"Mashproekt" GTR&PC in implementation of the program for renovation of Ukraine’s gas transportation system facilities. The mentioned state enterprise, as an originator of the method of compressor stations renovation by means of a heavy upgrading of gas pumping units, has a long experience of successful implementation of tens of such projects in the Russian Federation, Ukraine, Bulgaria. The examples and propositions for modernization of gas pipe-lines of "Ukrtransgaz" PJSC gas transportation sys-tem are set forth in the article

    Pinned Low Energy Electronic Excitation in Metal Exchanged Vanadium Oxide Nanoscrolls

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    We measured the optical properties of mixed valent vanadium oxide nanoscrolls and their metal exchanged derivatives in order to investigate the charge dynamics in these compounds. In contrast to the prediction of a metallic state for the metal exchanged derivatives within a rigid band model, we find that the injected charges in Mn2+^{2+} exchanged vanadium oxide nanoscrolls are pinned. A low-energy electronic excitation associated with the pinned carriers appears in the far infrared and persists at low temperature, suggesting that the nanoscrolls are weak metals in their bulk form, dominated by inhomogeneous charge disproportionation and Madelung energy effects.Comment: 4 figure

    Personalization framework for adaptive robotic feeding assistance

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    The final publication is available at link.springer.comThe deployment of robots at home must involve robots with pre-defined skills and the capability of personalizing their behavior by non-expert users. A framework to tackle this personalization is presented and applied to an automatic feeding task. The personalization involves the caregiver providing several examples of feeding using Learning-by- Demostration, and a ProMP formalism to compute an overall trajectory and the variance along the path. Experiments show the validity of the approach in generating different feeding motions to adapt to user’s preferences, automatically extracting the relevant task parameters. The importance of the nature of the demonstrations is also assessed, and two training strategies are compared. © Springer International Publishing AG 2016.Peer ReviewedPostprint (author's final draft

    Electrochemical Reducing of Terbium and Holmium Ions in the Sodium and Potassium Chlorides Melt with Equimolar Composition

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    Interest to rare-earth metals (REM) and their alloys is due to the possibility of using them for the creation of new materials need for modern technology. For instance, REM as alloying components allows for preparation of material with special magnetic properties. A promising method for forming such coating is the surface treatment of metals. This process has an electrochemical character as such for the organization of technology the knowledge of kinetics and mechanism of these processes is important. Despite significant interest in rare-earth metals, these issues are not well described in the literature. In order to choose an adequate mathematical model for calculation of kinetic primers, preliminary experiments that allow evaluating the reversibility of the electrode process have been conducted. Based on that, it was concluded that cathodic reduction of terbium and holmium ions in equimolar NaCl-KCl melt is irreversible. By means of voltammetric analysis, kinetic parameters (transfer coefficients, heterogeneous constants of charge transfer rate) of terbium and holmium electroreduction in equimolar NaCl-KCl melt were determined. The experiment was conducted in a three-electrode cell under a purified argon atmosphere. A dependency of kinetic parameters on the concentration of terbium and holmium chlorides wt (%): 1, 3, 5, 7, 10, was determined. The experiment was conducted in 1073–1173K temperature range. Values of kinetic parameters increase with temperature but decrease with the increase of REM chloride. Based on obtained data, it was found that electroreduction of chloride complexes LnCl63– (Ln–Tb, Ho) in equimolar NaCl-KCl melt is irreversible in the studied range of temperatures and REM concentrations. In summary of experimental data, in range of temperature and rare-earth chloride concentration, and assumption was made that reduction of terbium and holmium ions occurs in two stages. The process includes the preceding stage of complex dissociation. A mechanism of LnCl63– complex reduction in the mentioned melt is proposed. The obtained results are in agreement with literate data for analogues systems

    Efficient Model Learning for Human-Robot Collaborative Tasks

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    We present a framework for learning human user models from joint-action demonstrations that enables the robot to compute a robust policy for a collaborative task with a human. The learning takes place completely automatically, without any human intervention. First, we describe the clustering of demonstrated action sequences into different human types using an unsupervised learning algorithm. These demonstrated sequences are also used by the robot to learn a reward function that is representative for each type, through the employment of an inverse reinforcement learning algorithm. The learned model is then used as part of a Mixed Observability Markov Decision Process formulation, wherein the human type is a partially observable variable. With this framework, we can infer, either offline or online, the human type of a new user that was not included in the training set, and can compute a policy for the robot that will be aligned to the preference of this new user and will be robust to deviations of the human actions from prior demonstrations. Finally we validate the approach using data collected in human subject experiments, and conduct proof-of-concept demonstrations in which a person performs a collaborative task with a small industrial robot
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