scholarly journals Integrating Electrical Analogy and Computer Modeling of Groundwater Flow for Teaching Flownet Concepts

2013 ◽  
Vol 3 (4) ◽  
pp. 39
Author(s):  
Murthy Kasi ◽  
Yaping Chi ◽  
G. Padmanabhan
Keyword(s):  
Groundwater Flow ◽  
Steady Flow ◽  
Computer Model ◽  
Flow Problem ◽  
Lesson Plan ◽  
Mathematical Formulation ◽  
Electrical Current ◽  
Experimental Setup ◽  
Electrical Analogy ◽  
Electrical Current Flow

Laplace equation is the basic differential equation that governs the steady flow of a fluid through an isotropic and homogeneous porous medium and also the steady flow of current in a conducting medium. Therefore, a steady-state groundwater flow problem can be formulated as an analogous electrical current flow problem. A flow net, set of grids formed by orthogonally intersecting equipotential lines and flow lines, is a graphical solution to the equations of steady groundwater flow. By definition, flownet for the original groundwater problem and the corresponding analogous electrical problem should be similar. This feature allows the possibility of introducing the concepts of flownets to students using the easily demonstrable electrical counterpart of the problem in a laboratory setting. This paper discusses the efforts of the authors to widen the scope of an experiment already included in the Fluid Mechanics laboratory course of a Civil Engineering curriculum and to better teach flownet principles using the electrical analogy of groundwater flow problems. Students used a simple experimental setup to obtain flownets for selected groundwater flow situations with different boundary conditions using the electrical analogy concept. Students also used a groundwater flow computer model to obtain flownets for the same flow situations and compared the results. The laboratory lesson plan consisted of five steps: (i) study and understand the selected physical groundwater problems, (ii) conceptualize the corresponding analogous electrical problems (iii) use the electrical analogy experimental setup to obtain flownets, (iv) study and understand the mathematical formulation of the problems, and (v) compare the analogous results with those obtained from a groundwater flow computer model. Sample results obtained by students are presented. The student feedback indicated that this approach resulted in an effective learning of the concepts involved.

A computer model for the study of electrical current flow in the human thorax

1992 ◽  
Vol 22 (5) ◽  
pp. 305-323 ◽  
Author(s):  
Christopher R. Johnson ◽  
Robert S. MacLeod ◽  
Philip R. Ershler
Keyword(s):  
Computer Model ◽  
Current Flow ◽  
Electrical Current ◽  
Electrical Current Flow ◽  
Human Thorax

Electrical current flow at conductive nanowires formed in GaN thin films by a dislocation template technique

2010 ◽  
Vol 96 (19) ◽  
pp. 193109 ◽  
Author(s):  
Shin-ichi Amma ◽  
Yuki Tokumoto ◽  
Keiichi Edagawa ◽  
Naoya Shibata ◽  
Teruyasu Mizoguchi ◽  
...  
Keyword(s):  
Thin Films ◽  
Current Flow ◽  
Electrical Current ◽  
Electrical Current Flow

scholarly journals Моделирование источника ультрахолодных нейтронов на реакторе ПИК

2022 ◽  
Vol 92 (2) ◽  
pp. 327
Author(s):  
А.К. Фомин ◽  
А.П. Серебров
Keyword(s):  
Monte Carlo ◽  
Dipole Moment ◽  
Electric Dipole Moment ◽  
Computer Model ◽  
Electric Dipole ◽  
Monte Carlo Model ◽  
Ultracold Neutrons ◽  
Neutron Guide ◽  
Experimental Setup ◽  
Guide System

The paper presents the simulation of a complex of reserch with ultracold neutrons at the reactor PIK (Gatchina, Russia). The complex is being built on the basis of a high-intensity source of ultracold neutrons at the channel GEK-4. A Monte Carlo model has been developed, which includes a source, a neutron guide system and an experimental setup for search for the electric dipole moment of a neutron, taking into account their real location in the main hall of the reactor. Using the developed computer model the density of ultracold neutrons in the setup was obtained, which is 200 <sup>-3</sup>. It is 50 times higher than at the source at the Institut Laue-Langevin (Grenoble, France). This density will allow to achieve a sensitivity of measurements in the experiment of 1·10<sup>-27</sup> е·cm/year.

Effect of Current Direction on the Reliability of Different Capped Cu Interconnects

2005 ◽  
Vol 863 ◽  
Author(s):  
C. L. Gan ◽  
C. Y. Lee ◽  
C. K. Cheng ◽  
J. Gambino
Keyword(s):  
Failure Analysis ◽  
Current Flow ◽  
Void Nucleation ◽  
Electrical Current ◽  
Nucleation Site ◽  
Time To Failure ◽  
Current Direction ◽  
Electron Current ◽  
Electrical Current Flow ◽  
Better Than

AbstractThe reliability of Cu M1-V1-M2-V2-M3 interconnects with SiN and CoWP cap layers was investigated. Similar to previously reported results, the reliability of CoWP capped structures is much better than identical SiN capped structures. However, it was also observed that the reliability of CoWP capped interconnects was independent of the direction of electrical current flow. This phenomenon is different from what was observed for SiN capped structures, where M2 lines with electron current flow in the upstream configuration (“via-below”) have about three times larger median-time-to-failure than identical lines in the downstream configuration (“viaabove”). This is because the Cu/SiN interface is the preferential void nucleation site and provides the fastest diffusion pathway in such an architecture. Failure analysis has shown that fatal partially-spanned voids usually had formed directly below the via for “via-above” configuration, and fully-spanned voids occurred in the lines above the vias for “via-below” configuration.On the other hand, failure analysis for CoWP-coated Cu structures showed that partiallyspanned voids below the via do not cause fatal failures in the downstream configuration. This is because the CoWP layer is conducting, and thus able to shunt current around the void. As a result, a large fully-spanning void is required to cause a failure, just like the upstream configuration. Thus the lifetime of an interconnect with a conducting cap layer is independent of whether the current is flowing upstream or downstream.

scholarly journals Solution of the 3D density-driven groundwater flow problem with uncertain porosity and permeability

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Litvinenko ◽  
Dmitry Logashenko ◽  
Raul Tempone ◽  
Gabriel Wittum ◽  
David Keyes
Keyword(s):  
Groundwater Flow ◽  
Flow Problem ◽  
Two Phase ◽  
Contaminant Plumes ◽  
Quasi Monte Carlo ◽  
Strongly Nonlinear ◽  
Groundwater Aquifers ◽  
Porosity And Permeability ◽  
Liquid Flows ◽  
Computational Resources

AbstractThe pollution of groundwater, essential for supporting populations and agriculture, can have catastrophic consequences. Thus, accurate modeling of water pollution at the surface and in groundwater aquifers is vital. Here, we consider a density-driven groundwater flow problem with uncertain porosity and permeability. Addressing this problem is relevant for geothermal reservoir simulations, natural saline-disposal basins, modeling of contaminant plumes and subsurface flow predictions. This strongly nonlinear time-dependent problem describes the convection of a two-phase flow, whereby a liquid flows and propagates into groundwater reservoirs under the force of gravity to form so-called “fingers”. To achieve an accurate numerical solution, fine spatial resolution with an unstructured mesh and, therefore, high computational resources are required. Here we run a parallelized simulation toolbox ug4 with a geometric multigrid solver on a parallel cluster, and the parallelization is carried out in physical and stochastic spaces. Additionally, we demonstrate how the ug4 toolbox can be run in a black-box fashion for testing different scenarios in the density-driven flow. As a benchmark, we solve the Elder-like problem in a 3D domain. For approximations in the stochastic space, we use the generalized polynomial chaos expansion. We compute the mean, variance, and exceedance probabilities for the mass fraction. We use the solution obtained from the quasi-Monte Carlo method as a reference solution.

scholarly journals Nonconservative current-induced forces: A physical interpretation

2011 ◽  
Vol 2 ◽  
pp. 727-733 ◽  
Author(s):  
Tchavdar N Todorov ◽  
Daniel Dundas ◽  
Anthony T Paxton ◽  
Andrew P Horsfield
Keyword(s):  
Physical Interpretation ◽  
Current Flow ◽  
Test Procedure ◽  
Electrical Current ◽  
Stimulated Emission ◽  
General Definition ◽  
Noninvasive Test ◽  
Electrical Current Flow ◽  
Definition Of ◽  
A Current

We give a physical interpretation of the recently demonstrated nonconservative nature of interatomic forces in current-carrying nanostructures. We start from the analytical expression for the curl of these forces, and evaluate it for a point defect in a current-carrying system. We obtain a general definition of the capacity of electrical current flow to exert a nonconservative force, and thus do net work around closed paths, by a formal noninvasive test procedure. Second, we show that the gain in atomic kinetic energy over time, generated by nonconservative current-induced forces, is equivalent to the uncompensated stimulated emission of directional phonons. This connection with electron–phonon interactions quantifies explicitly the intuitive notion that nonconservative forces work by angular momentum transfer.

scholarly journals Peridynamic Formulation for Coupled Thermoelectric Phenomena

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Migbar Assefa ◽  
Xin Lai ◽  
Lisheng Liu ◽  
Yang Liao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Partial Differential Equations ◽  
Analytical Solutions ◽  
Current Flow ◽  
Numerical Technique ◽  
Electrical Current ◽  
Numerical Examples ◽  
Electrical Current Flow ◽  
Thermoelectric Convertor

Modeling of heat and electrical current flow simultaneously in thermoelectric convertor using classical theories do not consider the influence of defects in the material. This is because traditional methods are developed based on partial differential equations (PDEs) and lead to infinite fluxes at the discontinuities. The usual way of solving such PDEs is by using numerical technique, like Finite Element Method (FEM). Although FEM is robust and versatile, it is not suitable to model evolving discontinuities. To avoid such shortcomings, we propose the concept of peridynamic theory to derive the balance of energy and charge equations in the coupled thermoelectric phenomena. Therefore, this paper presents the transport of heat and charge in thermoelectric material in the framework of peridynamic (PD) theory. To illustrate the reliability of the PD formulation, numerical examples are presented and results are compared with those from literature, analytical solutions, or finite element solutions.

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