348 research outputs found

    The Jordan normal form of higher order Osserman algebraic curvature tensors

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    We construct new examples of algebraic curvature tensors so that the Jordan normal form of the higher order Jacobi operator is constant on the Grassmannian of subspaces of type (r,s)(r,s) in a vector space of signature (p,q)(p,q). We then use these examples to establish some results concerning higher order Osserman and higher order Jordan Osserman algebraic curvature tensors

    Quantum energy levels of hydrogen adsorbed on nanoporous carbons: an intrinsic probe for pore structure, and improving Monte Carlo simulations of adsorption [abstract]

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    Only abstract of poster available.Track IV: Materials for Energy ApplicationsHydrogen is the lightest molecule in nature, making both rotational and translational degrees of freedom eminently quantum mechanical (especially at low temperatures). For isolated molecules the first excited (degenerate) rotational states are at about 175 K above the (non-degenerate) ground state. When the hydrogen molecule is adsorbed, however, interaction with the substrate partially eliminates this degeneracy due to the different adsorption strengths of the different rotational states of the molecule. In this talk, we consider the adsorption of hydrogen in nanometer-size pores in carbon. We show that the rotation-vibration energy levels are strongly dependent on the pore structure (geometry and size). This dependence may be probed by inelastic neutron scattering as a local, non-destructive, probe intrinsic to the system, to characterize nanopores (in fact, using H2 as the probe makes sure that the pore structure probed is relevant for H2 adsorption). The rotation-vibration energy levels were also used as input for grand canonical Monte Carlo simulations of H2 adsorption, improving the accuracy of the simulations. This material is based on work supported by the U.S. Department of Energy under Award No. DE-FG02-07ER46411."This material is based on work supported by the U.S. Department of Energy under Award No. DE-FG02-07ER46411.

    Structural and energetic factors in designing a perfect nano-porous sorbent for hydrogen storage [abstract]

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    Only abstract of poster available.Track IV: Materials for Energy ApplicationsCarbons are one of several promising groups of materials for hydrogen storage by adsorption. However, the heat of hydrogen physisorption in such materials is low, in the range of about 4-8 kJ/mol which limits the total amount of hydrogen adsorbed at P = 100 bar to ~2 wt% at room temperature and about ~10 wt% at 77 K. To get better storage capacity, the adsorbing surfaces must be modified, either by substitution of some atoms in the all-carbon skeleton by other elements, or by doping/intercalation with other species. Here we analyze the variation of interaction energy between a molecule of hydrogen and graphene-based sorbents prepared as hypothetical modifications of the graphene layer. In particular, we show that partial substitution of carbons (for example, by boron) modifies both the symmetry of the energy landscape and strength of hydrogen physisorption. The effect of substituent extends over several sites of graphene lattice making the surface more heterogeneous. This material is based on work supported by the U.S. Department of Energy under Award No. DE-FG02-07ER46411."This material is based on work supported by the U.S. Department of Energy under Award No. DE-FG02-07ER46411.

    Personal Assistant Robot

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    Since the boom in science and technology, humans have been trying to invent machines that could reduce their efforts in day to day activities. In this paper, we develop a personal assistant robot that could pick up objects and return it to the user. The robot is controlled using an android application in mobile phones. The robot can listen to user’s command and then respond in the best way possible. The user can command the robot to move to given location, capture images and pick objects. The robot is equipped with ultrasonic sensor and web camera that helps it to move to different location effectively. It is also equipped with sleds that play important role in object picking process. The robot uses a tiny YOLOv3 model which is rigorously trained on several images of the object. There are some possible improvements that can be achieved which could help this robot to be used in several other fields as well
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