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Polymer-based microfluidic chips are becoming increasingly important for biological applications and fluidic control. In this article, we report and demonstrate a novel fabrication process of a Poly(dimethylsiloxane) (PDMS) device by casting fabrication technology, sometimes called soft lithography, which involves creation of positive mold containing the sub-20μm width microchannel microstructures...
The central task of current profile control during the ramp-up phase of a tokamak discharge is to find the actuator trajectories that are necessary to achieve certain desired current profile at some time between the end of the ramp-up phase and early stage of the flattop phase. The magnetic diffusion partial differential equation (PDE) models the dynamics of the poloidal magnetic flux profile, which...
The iterative learning control (ILC) technique is extended to distributed parameter systems governed by parabolic partial differential equations (PDEs). ILC arises as an effective method to approach constrained optimization problems in PDE systems. We discuss both P-type and D-type ILC schemes for a distributed parameter system formulated as a general linear system Sigma(A,B,C,D) on a Hilbert space,...
The accuracy of first-principles predictive models for the evolution of plasma profiles is sometimes limited by the lack of understanding of the plasma transport phenomena. It is possible then to develop approximate transport models for the prediction of the plasma dynamics which are consistent with the available diagnostic data. This data-driven approach, usually referred to as phenomenological modeling,...
The potential operation of a tokamak fusion reactor in a highly-efficient, steady-state mode is directly related to the achievement of certain types of radial profiles for the current flowing toroidally in the device. The evolution in time of the toroidal current profile in tokamaks is related to the evolution of the poloidal magnetic flux profile, which is modeled in normalized cylindrical coordinates...
In this paper, we study an optimal control problem arising in plasma transport which is governed by a singularly perturbed system. Time-scale separation allows us to focus on an uncoupled parabolic PDE with diffusivity-interior-boundary actuation. We prove the existence of the optimal control solution and carry out numerical experiments using quadratic programming (SQP).
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