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In this work we investigate numerically turbulent flow of low electrical conductivity fluid subject to electromagnetic ͑EMHD͒ forcing. The configuration is similar to the one considered in the experimental work of Henoch and Stace ͓Phys. Fluids 7, 1371 ͑1995͔͒ but in a channel geometry. The lower wall of the channel is covered with alternating streamwise electrodes and magnets to create a Lorentz force in the positive streamwise direction. Two cases are considered in detail corresponding to interaction parameter values of 0.4 ͑case 1͒ and 0.1 ͑case 2͒. The effect of switching off and on the electrodes is also studied for the two cases. At the Reynolds number considered ͑Re Ϸ200͒, a drag increase was obtained for all cases, in agreement with the experiments of Henoch and Stace. A Reynolds stress analysis was performed based on a new decomposition of the gradients normal to the wall of the Reynolds stress ϪuЈvЈ. It was found that the vortex stretching term wЈw 2 Ј and the spanwise variation of the stress component uЈwЈ are responsible for the drag increase. More specifically, the term ‫(ץ‬uЈwЈ)/‫ץ‬x 3 is associated with secondary vortical motions in the near-wall and becomes large and positive for large shear stress in regions where fluid is moving toward the wall. In contrast, negative values are associated with regions of lower shear where fluid is being lifted away from the wall. Unlike the unperturbed flow, in the controlled flow high speed near-wall streamwise jets are present ͑case 1͒ even in the time-averaged fields. Other changes in turbulence structure are quantified using streak spacing, vortex lines, vorticity quadrant analysis, and plots of the rms value of the vorticity angle.

The success of an on demand e-business requires that business process, application, and information technology (IT) infrastructure integration merge into a comprehensive and cohesive architecture, where business process transformation drives serviceoriented development and on demand enterprise computing. This enabling architecture is often described as a service-oriented architecture (SOA) and is a prerequisite accelerator for on demand solutions. The primary focus of SOA has been on dynamic reconfiguration of services from defined business processes, and on developing business services based on Web services and, more recently, grid services. Current descriptions of SOA are less focused on overall IT infrastructure enablement, both from a business policy perspective and within the context of service-oriented development. In this paper, we extend the current thinking on SOA to include a more comprehensive integration of business process transformation and the enabling technologies of service-oriented development and policy-based IT management. We call this extension on demand SOA. We develop these concepts by using an existing scenario: a financial services sector ''Life Change'' business process scenario, which involves distributed and disjoint transactions as well as stateless high-performance computing (HPC) applications.Over the last 40 years, information technology (IT) architectures and development approaches have dealt with increasing levels of IT complexity and integration challenges. Constrained budgets continue to mandate that legacy systems be reused rather than replaced. Growth by merger and acquisition requires that entire IT organizations be integrated and absorbed. Additionally, easy access to the Web has created the possibility for new business models, which must be evaluated for their potential.At the same time, the traditional needs of IT organizations persist-primarily focused on quick response to new requirements, typically consisting in turn of corporate management pushing for better IT utilization, skills simplification, greater return on investment (ROI), continued integration of historically separate systems, and faster implementation of new ones. The endless varieties of hardware, operating systems, middleware, languages, and data Ó

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In systems that exhibit a bistability between nonlinear traveling waves and the basic state, pairs of fronts connecting these two states can form localized wave pulses whose stability depends on the interaction between the fronts. We investigate wave pulses within the framework of coupled GinzburgLandau equations describing the traveling-wave amplitudes. We find that the introduction of resonant temporal forcing results in a new, tunable mechanism for stabilizing such wave pulses. In contrast to other localization mechanisms the temporal forcing can achieve localization by a repulsive as well as by an attractive interaction between the fronts. Systems for which the results are expected to be relevant include binary-mixture convection and electroconvection in nematic liquid crystals.