557 research outputs found

    Simulation of Micro-Electronic FlowFET Systems

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    A microelectronic fluidic system has been investigated by modeling and 3D simulation of fluid flow controlled by an applied gate voltage. The simulations have helped to characterize a novel FlowFET (a fluidic Field Effect Transistor) device under fault-free conditions. The FlowFET operates by applying a voltage field from a gate electrode in the insulated side wall of a microchannel to modulate the ␣-potential at the shear plane [1]. The change in ␣-potential can be used to control both the magnitude and direction of the electroosmotic flow in the microchannel

    Behavioral metabolution: the adaptive and evolutionary potential of metabolism-based chemotaxis

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    We use a minimal model of metabolism-based chemotaxis to show how a coupling between metabolism and behavior can affect evolutionary dynamics in a process we refer to as behavioral metabolution. This mutual influence can function as an in-the-moment, intrinsic evaluation of the adaptive value of a novel situation, such as an encounter with a compound that activates new metabolic pathways. Our model demonstrates how changes to metabolic pathways can lead to improvement of behavioral strategies, and conversely, how behavior can contribute to the exploration and fixation of new metabolic pathways. These examples indicate the potentially important role that the interplay between behavior and metabolism could have played in shaping adaptive evolution in early life and protolife. We argue that the processes illustrated by these models can be interpreted as an unorthodox instantiation of the principles of evolution by random variation and selective retention. We then discuss how the interaction between metabolism and behavior can facilitate evolution through (i) increasing exposure to environmental variation, (ii) making more likely the fixation of some beneficial metabolic pathways, (iii) providing a mechanism for in-the-moment adaptation to changes in the environment and to changes in the organization of the organism itself, and (iv) generating conditions that are conducive to speciatio

    Predicting the chances of a live birth after one or more complete cycles of in vitro fertilisation : population based study of linked cycle data from 113 873 women

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    Funding: This work was supported by a Chief Scientist Office postdoctoral training fellowship in health services research and health of the public research (ref PDF/12/06). The views expressed here are those of the authors and not necessarily those of the Chief Scientist Office. The funder did not have any role in the study design; the collection, analysis, and interpretation of data; the writing of the report; nor the decision to submit the paper for publication. DJM had full access to all the data in the study and had final responsibility for the decision to submit for publication.Peer reviewedPublisher PD

    Modeling of Micro-Electronic Fluidic Systems

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    A microelectronic fluidic system is studied using modeling and simulation of fluid flow controlled by applying gate voltage. 2D simulations were used to characterize the fluidic Field Effect Transistor (FlowFET) device under fault-free conditions. The FlowFET operates by applying a voltage from a gate electrode in the insulated side wall of a microchannel, to modulate the z-potential at the shear plane. The change in z-potential can be used to control both the magnitude and the direction of the electroosmotic flow in the microchannel

    Отказоустойчивый многофазный асинхронный электропривод с несинусоидальными токами

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    Рассмотрен принцип построения многофазного асинхронного электропривода, позволяющего при неоднократных отказах преобразователя частоты и двигателя обеспечить отказоустойчивое управление, на основе программируемых несинусоидальных токов с восстановлением работоспособности за счет активизации алгоритма восстановления в управляющем микроконтроллере. Приведены результаты моделирования для аварийной ситуации типа "обрыв фазы" для случая трехфазного двигателя с частичным восстановлением работоспособности асинхронного двигателя
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