Schrodinger equation for the one particle density matrix of thermal systems: An alternative formulation of Bose-Einstein condensation

We formulate a linear Schrodinger equation with the temperature-dependent potential for the one-particle density matrix and obtain the condensation temperature of the Bose-Einstein condensate from a bound-state condition for the Schrodinger equation both with and without the confining trap. The results are in very good agreement with those of the full statistical physics treatment. This is an alternative to the Bose-Einstein condensation in the standard ideal Bose gas treatment.Comment: 4 pages, 2 figure

A Hardy's Uncertainty Principle Lemma in Weak Commutation Relations of Heisenberg-Lie Algebra

In this article we consider linear operators satisfying a generalized commutation relation of a type of the Heisenberg-Lie algebra. It is proven that a generalized inequality of the Hardy's uncertainty principle lemma follows. Its applications to time operators and abstract Dirac operators are also investigated

Chaotic exploration and learning of locomotion behaviours

We present a general and fully dynamic neural system, which exploits intrinsic chaotic dynamics, for the real-time goal-directed exploration and learning of the possible locomotion patterns of an articulated robot of an arbitrary morphology in an unknown environment. The controller is modeled as a network of neural oscillators that are initially coupled only through physical embodiment, and goal-directed exploration of coordinated motor patterns is achieved by chaotic search using adaptive bifurcation. The phase space of the indirectly coupled neural-body-environment system contains multiple transient or permanent self-organized dynamics, each of which is a candidate for a locomotion behavior. The adaptive bifurcation enables the system orbit to wander through various phase-coordinated states, using its intrinsic chaotic dynamics as a driving force, and stabilizes on to one of the states matching the given goal criteria. In order to improve the sustainability of useful transient patterns, sensory homeostasis has been introduced, which results in an increased diversity of motor outputs, thus achieving multiscale exploration. A rhythmic pattern discovered by this process is memorized and sustained by changing the wiring between initially disconnected oscillators using an adaptive synchronization method. Our results show that the novel neurorobotic system is able to create and learn multiple locomotion behaviors for a wide range of body configurations and physical environments and can readapt in realtime after sustaining damage

Development of a chromium-thoria alloy

Low temperature ductility and high temperature strength of pure chromium and chromium-thoria alloy prepared from vapor deposited powder

First order wetting of rough substrates and quantum unbinding

Replica and functional renormalization group methods show that, with short range substrate forces or in strong fluctuation regimes, wetting of a self-affine rough wall in 2D turns first-order as soon as the wall roughness exponent exceeds the anisotropy index of bulk interface fluctuations. Different thresholds apply with long range forces in mean field regimes. For bond-disordered bulk, fixed point stability suggests similar results, which ultimately rely on basic properties of quantum bound states with asymptotically power-law repulsive potentials.Comment: 11 pages, 1 figur

STATIC TESTS ON COLLAPSING GUARDRAIL DESIGNS

A modified turned-down guardrail terminal which uses retrofit clips to hold up the guardrail has been in use on Nebraska Highways for several years. During this time, the Nebraska Department of Roads has become aware of a problem with this design. After being exposed to temperature fluctuations and vibrations from passing traffic the retrofit clips expand and the guardrail drops to the ground. Twelve different designs were tested on an actual guardrail field installation and a design consisting of strategically placed shear bolts was recommended

Effect of metal precursor on Cu/ZnO/Al₂O₃ synthesized by flame spray pyrolysis for direct DME production

Cu/ZnO/Al2O3 catalysts were synthesized by flame spray pyrolysis (FSP). The effect of different metal precursor types, i.e. metal nitrates and organometallics, on the catalytic properties was investigated. Organometallic precursors are commonly used for flame spray pyrolysis because small nanoparticles can be produced. In this study, we have obtained nanosized copper and zinc oxide clusters also from the nitrate precursors. Characterization was applied to reveal the difference between the clusters obtained from the different precursor types. Both precursors allowed the formation of well-ordered Cu/ZnO/Al2O3 particles with similar size according to TEM investigations. However, the catalyst from metal nitrate precursors possessed a lower reduction temperature, a higher active copper surface area, and a lower overall BET surface area than the one from the organometallic precursor. The catalytic performance of the obtained catalysts was investigated in the direct DME synthesis from synthesis gas. Methanol dehydration catalyst, H-ZSM-5, was therefore admixed to the FSP powders in a pre-defined amount; the FSP powders served as methanol synthesis catalyst in the mixture. The catalyst from metal nitrate precursors showed higher conversion of syngas than the catalyst from the organometallic precursors at same reaction conditions. This effect can be explained mainly by the higher copper surface area. Catalysts with different Cu/Zn ratio were also tested and the best catalyst was further studied by variation of the reaction conditions. In conclusion, we have demonstrated an efficient utilization of less expensive precursor materials for flame spray pyrolysis for production of Cu/ZnO/Al2O3 catalysts