Browsing by Subject "Numerical Modeling"

Now showing 1 - 3 of 3
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    The anti-arrhythmic effects of constant diastolic interval pacing in a numerical model of a canine cardiac ventricular fiber
    (2016-06) Johnson, Christopher
    Beat to beat changes in action potential duration (APD) are known as alternans. Alternans are precursors for cardiac arrhythmias that may lead to heart failure and sudden cardiac death. Sudden cardiac death makes up 15-20% of all deaths annually in the United States (Deo, [28]). Alternans are known to form in association with periodic pacing protocol, during which the basic cycle length (BCL) is held constant. Periodic pacing incorporates feedback from the previous action potential, allowing for the formation of alternans. Constant diastolic interval (DI) pacing relies on the elimination of feedback within the system, and through the elimination causes the suppression of alternans. It has previously been shown that alternans suppression within a single cell model is possible (McIntyre, [22]). This research focuses on the presence and behavior of alternans in a 150 cell (1.5cm) and a 300 cell (3cm) cable during constant BCL and constant DI pacing. Alternans did appear for constant DI pacing for DI values lower than 20ms, representing a non-physiological range. However, we found that alternans could be controlled using a constant DI pacing protocol for both a short and long cable when using physiological ranges for DI, above 30ms.
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    Numerical Model for the propagation of Alfven Waves produced by Jupiter's moon Io
    (2022-11-28) Lysak, Robert L; lysak001@umn.edu; Lysak, Robert L; Minnesota Institute for Astrophysics Space Physics Group
    We present first results from a new numerical model to describe the propagation of these Alfvén waves in the Io-Jupiter system. The model is cast in magnetic dipole coordinates and includes a dense plasma torus that is centered around the centrifugal equator. Results are presented for two density models, showing the dependence of the interaction on the magnetospheric density. The effect of the conductance of Jupiter’s ionosphere is considered. A model for the development of parallel electric fields is introduced, indicating that the main auroral footprints of Io can generated parallel potentials of up to 100 kV.
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    Supporting data for A Model Sensitivity Study of Ocean Surface Wave Modulation Induced by Internal Waves
    (2022-11-03) Wu, Jie; Ortiz-Suslow, David G; Hao, Xuanting; Wang, Qing; Shen, Lian; wuxx1417@umn.edu; Wu, Jie; University of Minnesota Fluid Mechanics Lab
    The dataset is generated using the two-layer fluid model to simulate internal and surface wave interaction. It can be used to analyze the impact of internal wave and surface wave properties on internal wave-induced surface wave modulation.