1,762 research outputs found

    Intelligent Based Terrain Preview Controller for a 3-axle Vehicle

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    Presented at 13th International Symposium on Advanced Vehicle Control, AVEC'16; Munich 13-16/09/2016The paper presents a six-wheel half longitudinal model and the design of a dual level control architecture. The first (top) level is designed using a Sugeno fuzzy inference feedforward architecture with and without preview. The second level of controllers are locally managing each wheel for each axle. As the vehicle is moving forward the front wheels and suspension units will have less time to respond when compared to the middle and rear units, hence a preview sensor is used to compensate. The paper shows that the local active suspensions together with the Sugeno Fuzzy, (locally optimised using subtractive clustering), Feedforward control strategy is more effective and this architecture has resulted in reducing the sprung mass vertical acceleration and pitch accelerations

    Measurement of an integral of a classical field with a single quantum particle

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    A method for measuring an integral of a classical field via local interaction of a single quantum particle in a superposition of 2^N states is presented. The method is as efficient as a quantum method with N qubits passing through the field one at a time and it is exponentially better than any known classical method that uses N bits passing through the field one at a time. A related method for searching a string with a quantum particle is proposed.Comment: 3 page

    Is Small Perfect? Size Limit to Defect Formation in Pyramidal Pt Nanocontacts

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    We report high resolution transmission electron microscopy and ab initio calculation results for the defect formation in Pt nanocontacts (NCs). Our results show that there is a size limit to the existence of twins (extended structural defects). Defects are always present but blocked away from the tip axes. The twins may act as scattering plane, influencing contact electron transmission for Pt NC at room temperature and Ag/Au NC at low temperature.Comment: 4 pages, 3 figure

    Entanglement and the nonlinear elastic behavior of forests of coiled carbon nanotubes

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    Helical or coiled nanostructures have been object of intense experimental and theoretical studies due to their special electronic and mechanical properties. Recently, it was experimentally reported that the dynamical response of foamlike forest of coiled carbon nanotubes under mechanical impact exhibits a nonlinear, non-Hertzian behavior, with no trace of plastic deformation. The physical origin of this unusual behavior is not yet fully understood. In this work, based on analytical models, we show that the entanglement among neighboring coils in the superior part of the forest surface must be taken into account for a full description of the strongly nonlinear behavior of the impact response of a drop-ball onto a forest of coiled carbon nanotubes.Comment: 4 pages, 3 figure

    Curved Graphene Nanoribbons: Structure and Dynamics of Carbon Nanobelts

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    Carbon nanoribbons (CNRs) are graphene (planar) structures with large aspect ratio. Carbon nanobelts (CNBs) are small graphene nanoribbons rolled up into spiral-like structures, i. e., carbon nanoscrolls (CNSs) with large aspect ratio. In this work we investigated the energetics and dynamical aspects of CNBs formed from rolling up CNRs. We have carried out molecular dynamics simulations using reactive empirical bond-order potentials. Our results show that similarly to CNSs, CNBs formation is dominated by two major energy contribution, the increase in the elastic energy due to the bending of the initial planar configuration (decreasing structural stability) and the energetic gain due to van der Waals interactions of the overlapping surface of the rolled layers (increasing structural stability). Beyond a critical diameter value these scrolled structures can be even more stable (in terms of energy) than their equivalent planar configurations. In contrast to CNSs that require energy assisted processes (sonication, chemical reactions, etc.) to be formed, CNBs can be spontaneously formed from low temperature driven processes. Long CNBs (length of ∌\sim 30.0 nm) tend to exhibit self-folded racket-like conformations with formation dynamics very similar to the one observed for long carbon nanotubes. Shorter CNBs will be more likely to form perfect scrolled structures. Possible synthetic routes to fabricate CNBs from graphene membranes are also addressed

    Proposed experiment for the quantum "Guess my number" protocol

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    An experimental realization of the entanglement-assisted "Guess my number" protocol for the reduction of communication complexity, introduced by Steane and van Dam, would require producing and detecting three-qubit GHZ states with an efficiency eta > 0.70, which would require single photon detectors of efficiency sigma > 0.89. We propose a modification of the protocol which can be translated into a real experiment using present-day technology. In the proposed experiment, the quantum reduction of the multi-party communication complexity would require an efficiency eta > 0.05, achievable with detectors of sigma > 0.47, for four parties, and eta > 0.17 (sigma > 0.55) for three parties.Comment: REVTeX4, 4 pages, 1 figur

    Size Limit Of Defect Formation In Pyramidal Pt Nanocontacts.

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    We report high resolution transmission electron microscopy and ab initio calculation results for defect formation in sharp pyramidal Pt nanocontacts. Our results show that there is a size limit to the existence of twins (extended structural defects). These defects are always present but blocked away from the tip axes. They may act as scattering planes, influencing the electron conductance for Pt nanocontacts at room temperature and Ag/Au nanocontacts at low temperature (<150 K).9925550

    Mechanical Deformation Of Nanoscale Metal Rods: When Size And Shape Matter.

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    Face centered cubic metals deform mainly by propagating partial dislocations generating planar fault ribbons. How do metals deform if the size is smaller than the fault ribbons? We studied the elongation of Au and Pt nanorods by in situ electron microscopy and ab initio calculations. Planar fault activation barriers are so low that, for each temperature, a minimal rod size is required to become active for releasing elastic energy. Surface effects dominate deformation energetics; system size and shape determine the preferred fault gliding directions which induce different tensile and compressive behavior.10605550

    Portuguese Adaptation of Students Engagement in Schools International Scale (SESIS)

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    The importance of student’s engagement has been recently pointed out in research. However, there has been a lack of engagement assessment instrument, pertaining psychometric qualities. Objective: This paper presents the Portuguese adaptation of the “Student’s Engagement in School International Scale” (SESIS), drawn up from a12 countries international study (Lam et al., 2012; Lam et al., in press). Method: Psychometric properties of this scale were examined with data from 685 students from different grades (6th, 7th, 9th and 10th), from both sexes, and different regions of the country. Results: Factorial analysis of the results, with varimax rotation, lead to three different factors which explain 50.88% of the variance. The scale integrates the original 33 items, and cognitive, affective and behavioural dimensions. For the external validity study, the relationship between student’s engagement in school results and other school variables — academic performance, self-concept — was considered, and significant relations were observed, as expected. Conclusion: The data presented highlights the qualities of SESIS, as well as its usefulness for research purposes. Suggestion: It is suggested the investigation of the extension of SESIS’s three-dimensionality, in future studiesKeywords: Innovation, technology, research projects, etc. [Arial 10-point, justified alignment]
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