Lie discrete symmetries of lattice equations

We extend two of the methods previously introduced to find discrete symmetries of differential equations to the case of difference and differential-difference equations. As an example of the application of the methods, we construct the discrete symmetries of the discrete Painlev\'e I equation and of the Toda lattice equation

Multiscale expansion and integrability properties of the lattice potential KdV equation

We apply the discrete multiscale expansion to the Lax pair and to the first few symmetries of the lattice potential Korteweg-de Vries equation. From these calculations we show that, like the lowest order secularity conditions give a nonlinear Schroedinger equation, the Lax pair gives at the same order the Zakharov and Shabat spectral problem and the symmetries the hierarchy of point and generalized symmetries of the nonlinear Schroedinger equation.Comment: 10 pages, contribution to the proceedings of the NEEDS 2007 Conferenc

Evaluation of Masters Choice Corn Silage on Growing Steer Performance

A growing study evaluated three corn silage hybrids on growing steer performance. Th e three hybrids were: a conventional hybrid- Farm Choice (CON) commonly grown in Eastern Nebraska which served as the control, Masters Choice hybrids MCT6365 RIB (MC1) selected to improve fi ber and starch digestion and MCT6733 GT3000 (MC2) that has been selected to improve fi ber digestion in cattle. Relative to CON, feeding hybrid MC1 resulted in similar DMI, but numerically increased ADG which significantly improved F:G compared to CON. Feeding MC2 led to greater DMI, similar ADG, and poorer (greater) F:G compared to CON. Feeding Masters Choice hybrid MCT6365 RIB (MC1) corn silage at 80% of the diet DM likely improved digestion and energy availability to the steers, which allowed greater ADG and improved F:G, while the opposite was true for MC2. Differences in hybrids exist when fed to growing cattle at 80% of the diet

Thermal characterization of a multilayer coating for seismic and energy building renovation

Many buildings built in Italy in the 60s and 70s need an energy requalification and at the same time an improvement of the seismic behaviour. A non-invasive method for a joint requalification consists of an anti-seismic plaster layer and a thermal coating. In this work, a multi-layer package of 3 cm of SFRM coating and 8 cm of wood fiber placed on a 20 cm masonry wall is analyzed. Numerical and experimental analysis allowed to characterize the wall, and to determine the influence of the connecting elements

Isolated Chargers for EVs Incorporating Six-Phase Machines

This paper considers two isolated solutions for fast charging of electric vehicles (EVs). The isolation is located on the grid side (off board), whereas the rest of the charging apparatus is placed on board the EV, and it entirely consists of the existing power electronics components that would be otherwise used only for propulsion. Thus, substantial savings on space, weight, and cost are achieved. The considered configurations fully incorporate either a symmetrical or an asymmetrical six-phase machine, as well as a six-phase inverter, into the charging process. Due to the nature of the connections, torque production is avoided during the charging/vehicle-to-grid (V2G) modes of operation. Thus, the machines do not have to be mechanically locked, and their rotors naturally stay at standstill. Control schemes for both configurations are elaborated, and theoretical results are validated by experiments for the two configurations in both charging and V2G modes

Mesons and Flavor on the Conifold

We explore the addition of fundamental matter to the Klebanov-Witten field theory. We add probe D7-branes to the ${\cal N}=1$ theory obtained from placing D3-branes at the tip of the conifold and compute the meson spectrum for the scalar mesons. In the UV limit of massless quarks we find the exact dimensions of the associated operators, which exhibit a simple scaling in the large-charge limit. For the case of massive quarks we compute the spectrum of scalar mesons numerically.Comment: 19 pages, 3 figures, v2: typos fixe

Modelling Approaches for Triple Three-Phase Permanent Magnet Machines

Standard modelling approaches for a triple three-phase (i.e. nine-phase) machine include vector space decomposition (VSD) and triple d-q modelling procedure. Each is characterised with certain benefits and shortcomings. This paper introduces a novel transformation, applicable to multiple three-phase winding machines in general, especially aimed at facilitating the power (current) sharing between the three-phase systems. The easiness of the current sharing with the novel transformation, introduced here, is demonstrated via simulations in MATLAB

Multiscale reduction of discrete nonlinear Schroedinger equations

We use a discrete multiscale analysis to study the asymptotic integrability of differential-difference equations. In particular, we show that multiscale perturbation techniques provide an analytic tool to derive necessary integrability conditions for two well-known discretizations of the nonlinear Schroedinger equation.Comment: 12 page

A Novel Synthetic Loading Method for Multiple Three-phase Winding Electric Machines

The paper develops a version of the synthetic loading method, suitable for testing of multiphase machines with multiple three-phase distributed windings. The method is at first discussed in general terms for a structure with k three-phase stator windings (i.e. total number of phases is n = 3k). Subsequent detailed development is described for a dual three-phase (six-phase) stator winding configuration. With a control architecture that allows the use of half of the three-phase windings as a motor and the other half as a generator, the machine (and/or the converter) can be tested under full rated power without the need for any mechanical load. Moreover, the power consumed from the grid is in essence equal only to the total losses of the system. Modelling, based on the double d-q approach, and the control layout that includes full cross-coupling decoupling are described for a permanent magnet (PM) synchronous machine. An experimental test rig with a double three-phase PM machine of 150 kW rating is detailed and the samples of experimental results are provided to verity the theoretical considerations

Modelling Approaches for Triple Three-Phase Permanent Magnet Machines

Standard modelling approaches for a triple three-phase (i.e. nine-phase) machine include vector space decomposition (VSD) and triple d-q modelling procedure. Each is characterised with certain benefits and shortcomings. This paper introduces a novel transformation, applicable to multiple three-phase winding machines in general, especially aimed at facilitating the power (current) sharing between the three-phase systems. The easiness of the current sharing with the novel transformation, introduced here, is demonstrated via simulations in MATLAB