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Full-Text Articles in Physical Sciences and Mathematics

Full Isolation Number Of Matrices: Some Extremal Results, David Tate, David Brown Dec 2015

Full Isolation Number Of Matrices: Some Extremal Results, David Tate, David Brown

David C. Brown

A set of nonzero entries of a (0,1)-matrix is an isolated set if no two entries belong to the same row, no two entries belong to the same column, and no two entries belong to a submatrix of the form [1 1; 1 1]. The isolation number of a matrix is the maximum size over all isolated sets. The isolation number of a matrix is a well-known and well-used lower bound for the matrix's Boolean rank. We will discuss the isolation number of the adjacency matrix of various graphs and develop some extremal results for n x n matrices with …


Localized Corrosion Risk Assessment Using Markov Analysis, K Mccallum, J Zhao, M Workman, M Iannuzzi, M Kappes, Joe Payer, Curtis Clemons, S Chawla, Kevin Kreider, Nao Mimoto, Gerald Young Sep 2015

Localized Corrosion Risk Assessment Using Markov Analysis, K Mccallum, J Zhao, M Workman, M Iannuzzi, M Kappes, Joe Payer, Curtis Clemons, S Chawla, Kevin Kreider, Nao Mimoto, Gerald Young

Gerald W Young

The objective of this work was to develop the foundation for an interactive corrosion risk management tool for assessing the probability of failure of equipment/infrastructure as a function of threats (such as pitting corrosion and coating degradation) and mitigation schemes (such as inhibitors and coatings). The application of this work was to assist with corrosion management and maintenance planning of equipment/infrastructure given dynamic changes in environmental conditions. Markov models are developed to estimate pitting damage accumulation density distributions as a function of input parameters for pit nucleation and growth rates. The input parameters are selected based upon characterization with experimental …


One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard Sep 2015

One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard

Gerald W Young

A one-dimensional mathematical model is developed to describe time-dependent damage evolution in well-mixed (spatially uniform species concentrations) galvanic systems using an IR drop approach. An asymptotic procedure taking advantage of disparity in length scales (thin film approximation for the electrolyte thickness) is used to derive the model. Limitations that result from the reduction of dimension are described, along with an analysis demonstrating the ability of the 1D model to capture physical phenomena, such as area ratio effects. Computed potential, current density, and corrosion damage profiles are compared and verified with experimental data available in the literature and 2D galvanic corrosion …


An Adaptive Level Set Approach For Modeling Damage Due To Galvanic Corrosion, Joseph Wilder, Curtis Clemons, Dmitry Golovaty, Kevin Kreider, Gerald Young, R. Lillard Sep 2015

An Adaptive Level Set Approach For Modeling Damage Due To Galvanic Corrosion, Joseph Wilder, Curtis Clemons, Dmitry Golovaty, Kevin Kreider, Gerald Young, R. Lillard

Gerald W Young

This article presents an approach to solving problems related to galvanic corrosion that involve moving boundaries (due to preferential corrosion of one of the metals in the system). The method incorporates an adaptive (node based, finite difference) grid technique for the treatment of boundary-related singularities that arise in the calculation of the electric potential. Simulation of the time evolution of the damage done by the corroding interface is performed using of a level set formulation. An analysis of the convergence of the method and a comparison with experimental data from the literature are included.


Global Magnetic Confinement For The 1.5d Vlasov-Maxwell System, Toan Nguyen, Truyen Nguyen, Walter Strauss Sep 2015

Global Magnetic Confinement For The 1.5d Vlasov-Maxwell System, Toan Nguyen, Truyen Nguyen, Walter Strauss

Truyen V. Nguyen

We establish the global-in-time existence and uniqueness of classical solutions to the ``one and one-half'' dimensional relativistic Vlasov--Maxwell systems in a bounded interval, subject to an external magnetic field which is infinitely large at the spatial boundary. We prove that the large external magnetic field confines the particles to a compact set away from the boundary. This excludes the known singularities that typically occur due to particles that repeatedly bounce off the boundary. In addition to the confinement, we follow the techniques introduced by Glassey and Schaeffer, who studied the Cauchy problem without boundaries.


One-Dimensional Pressureless Gas Systems With/Without Viscosity, Truyen Nguyen, Adrian Tudorascu Sep 2015

One-Dimensional Pressureless Gas Systems With/Without Viscosity, Truyen Nguyen, Adrian Tudorascu

Truyen V. Nguyen

A general global existence result for one-dimensional pressureless Euler/Euler-Poisson systems with or without viscosity is obtained by employing the “sticky particles” model. We first construct entropy solutions for some appropriate scalar conservation laws, then we show that these solutions encode all the information necessary to obtain solutions for the pressureless systems. Another novel contribution is the stability and uniqueness of solutions, which is obtained via a contraction principle in the Wasserstein metric.


One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard Sep 2015

One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard

Kevin L. Kreider

A one-dimensional mathematical model is developed to describe time-dependent damage evolution in well-mixed (spatially uniform species concentrations) galvanic systems using an IR drop approach. An asymptotic procedure taking advantage of disparity in length scales (thin film approximation for the electrolyte thickness) is used to derive the model. Limitations that result from the reduction of dimension are described, along with an analysis demonstrating the ability of the 1D model to capture physical phenomena, such as area ratio effects. Computed potential, current density, and corrosion damage profiles are compared and verified with experimental data available in the literature and 2D galvanic corrosion …


An Adaptive Level Set Approach For Modeling Damage Due To Galvanic Corrosion, Joseph Wilder, Curtis Clemons, Dmitry Golovaty, Kevin Kreider, Gerald Young, R. Lillard Sep 2015

An Adaptive Level Set Approach For Modeling Damage Due To Galvanic Corrosion, Joseph Wilder, Curtis Clemons, Dmitry Golovaty, Kevin Kreider, Gerald Young, R. Lillard

Kevin L. Kreider

This article presents an approach to solving problems related to galvanic corrosion that involve moving boundaries (due to preferential corrosion of one of the metals in the system). The method incorporates an adaptive (node based, finite difference) grid technique for the treatment of boundary-related singularities that arise in the calculation of the electric potential. Simulation of the time evolution of the damage done by the corroding interface is performed using of a level set formulation. An analysis of the convergence of the method and a comparison with experimental data from the literature are included.


Localized Corrosion Risk Assessment Using Markov Analysis, K Mccallum, J Zhao, M Workman, M Iannuzzi, M Kappes, Joe Payer, Curtis Clemons, S Chawla, Kevin Kreider, Nao Mimoto, Gerald Young Sep 2015

Localized Corrosion Risk Assessment Using Markov Analysis, K Mccallum, J Zhao, M Workman, M Iannuzzi, M Kappes, Joe Payer, Curtis Clemons, S Chawla, Kevin Kreider, Nao Mimoto, Gerald Young

Kevin L. Kreider

The objective of this work was to develop the foundation for an interactive corrosion risk management tool for assessing the probability of failure of equipment/infrastructure as a function of threats (such as pitting corrosion and coating degradation) and mitigation schemes (such as inhibitors and coatings). The application of this work was to assist with corrosion management and maintenance planning of equipment/infrastructure given dynamic changes in environmental conditions. Markov models are developed to estimate pitting damage accumulation density distributions as a function of input parameters for pit nucleation and growth rates. The input parameters are selected based upon characterization with experimental …


One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard Sep 2015

One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard

Dimitry Golovaty

A one-dimensional mathematical model is developed to describe time-dependent damage evolution in well-mixed (spatially uniform species concentrations) galvanic systems using an IR drop approach. An asymptotic procedure taking advantage of disparity in length scales (thin film approximation for the electrolyte thickness) is used to derive the model. Limitations that result from the reduction of dimension are described, along with an analysis demonstrating the ability of the 1D model to capture physical phenomena, such as area ratio effects. Computed potential, current density, and corrosion damage profiles are compared and verified with experimental data available in the literature and 2D galvanic corrosion …


On A Conjecture Of Gluck, James Cossey, Zoltan Halasi, Attila Maroti, Hung Nuguyen Sep 2015

On A Conjecture Of Gluck, James Cossey, Zoltan Halasi, Attila Maroti, Hung Nuguyen

James P. Cossey

Let F(G) and b(G) respectively denote the Fitting subgroup and the largest degree of an irreducible complex character of a finite group G. A well-known conjecture of D. Gluck claims that if G is solvable then |G:F(G)|≤b(G)2. We confirm this conjecture in the case where |F(G)| is coprime to 6. We also extend the problem to arbitrary finite groups and prove several results showing that the largest irreducible character degree of a finite group strongly controls the group structure.


One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard Sep 2015

One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard

Curtis B. Clemons

A one-dimensional mathematical model is developed to describe time-dependent damage evolution in well-mixed (spatially uniform species concentrations) galvanic systems using an IR drop approach. An asymptotic procedure taking advantage of disparity in length scales (thin film approximation for the electrolyte thickness) is used to derive the model. Limitations that result from the reduction of dimension are described, along with an analysis demonstrating the ability of the 1D model to capture physical phenomena, such as area ratio effects. Computed potential, current density, and corrosion damage profiles are compared and verified with experimental data available in the literature and 2D galvanic corrosion …


An Adaptive Level Set Approach For Modeling Damage Due To Galvanic Corrosion, Joseph Wilder, Curtis Clemons, Dmitry Golovaty, Kevin Kreider, Gerald Young, R. Lillard Sep 2015

An Adaptive Level Set Approach For Modeling Damage Due To Galvanic Corrosion, Joseph Wilder, Curtis Clemons, Dmitry Golovaty, Kevin Kreider, Gerald Young, R. Lillard

Curtis B. Clemons

This article presents an approach to solving problems related to galvanic corrosion that involve moving boundaries (due to preferential corrosion of one of the metals in the system). The method incorporates an adaptive (node based, finite difference) grid technique for the treatment of boundary-related singularities that arise in the calculation of the electric potential. Simulation of the time evolution of the damage done by the corroding interface is performed using of a level set formulation. An analysis of the convergence of the method and a comparison with experimental data from the literature are included.


Localized Corrosion Risk Assessment Using Markov Analysis, K Mccallum, J Zhao, M Workman, M Iannuzzi, M Kappes, Joe Payer, Curtis Clemons, S Chawla, Kevin Kreider, Nao Mimoto, Gerald Young Sep 2015

Localized Corrosion Risk Assessment Using Markov Analysis, K Mccallum, J Zhao, M Workman, M Iannuzzi, M Kappes, Joe Payer, Curtis Clemons, S Chawla, Kevin Kreider, Nao Mimoto, Gerald Young

Curtis B. Clemons

The objective of this work was to develop the foundation for an interactive corrosion risk management tool for assessing the probability of failure of equipment/infrastructure as a function of threats (such as pitting corrosion and coating degradation) and mitigation schemes (such as inhibitors and coatings). The application of this work was to assist with corrosion management and maintenance planning of equipment/infrastructure given dynamic changes in environmental conditions. Markov models are developed to estimate pitting damage accumulation density distributions as a function of input parameters for pit nucleation and growth rates. The input parameters are selected based upon characterization with experimental …


Localized Corrosion Risk Assessment Using Markov Analysis, K Mccallum, J Zhao, M Workman, M Iannuzzi, M Kappes, Joe Payer, Curtis Clemons, S Chawla, Kevin Kreider, Nao Mimoto, Gerald Young Sep 2015

Localized Corrosion Risk Assessment Using Markov Analysis, K Mccallum, J Zhao, M Workman, M Iannuzzi, M Kappes, Joe Payer, Curtis Clemons, S Chawla, Kevin Kreider, Nao Mimoto, Gerald Young

Nao Mimoto

The objective of this work was to develop the foundation for an interactive corrosion risk management tool for assessing the probability of failure of equipment/infrastructure as a function of threats (such as pitting corrosion and coating degradation) and mitigation schemes (such as inhibitors and coatings). The application of this work was to assist with corrosion management and maintenance planning of equipment/infrastructure given dynamic changes in environmental conditions. Markov models are developed to estimate pitting damage accumulation density distributions as a function of input parameters for pit nucleation and growth rates. The input parameters are selected based upon characterization with experimental …


Skew-Product Dynamical Dystems: Applications To Difference Equations, Saber Elaydi, Robert Sacker Aug 2015

Skew-Product Dynamical Dystems: Applications To Difference Equations, Saber Elaydi, Robert Sacker

Saber Elaydi

No abstract provided.


Asymptotic Solutions Of A Discrete Schrödinger Equation Arising From A Dirac Equation With Random Mass, Bernd Aulbach, Saber Elaydi, Klaus Ziegler Aug 2015

Asymptotic Solutions Of A Discrete Schrödinger Equation Arising From A Dirac Equation With Random Mass, Bernd Aulbach, Saber Elaydi, Klaus Ziegler

Saber Elaydi

For a Dirac particle in one dimension with random mass, the time evolution for the average wavefunction is considered. Using the supersymmetric representation of the average Green’s function, we derive a fourth order linear difference equation for the low-energy asymptotics of the average wavefunction. This equation is of Poincar´e type, though highly critical and therefore not amenable to standard methods. In this paper we show that, nevertheless, asymptotic expansions of its solutions can be obtained.


Difference Equations Versus Differential Equations, A Possible Equivalence For The Rössler System?, Christophe Letellier, Saber Elaydi, Luis Aguirre, Aziz Alaoui Aug 2015

Difference Equations Versus Differential Equations, A Possible Equivalence For The Rössler System?, Christophe Letellier, Saber Elaydi, Luis Aguirre, Aziz Alaoui

Saber Elaydi

When a set of non linear differential equations is investigated, most of the time there is no analytical solution and only numerial integration techniques can provide accurate numerical solutions. In a general way the process of numerical integration is the replacement of a set of differential equations with a continuous dependence on the time by a model for which these time variable is discrete. When only a numerical solution is researched, a fourth-order Runge-Kutta integration scheme is usually sufficient. Nevertheless, sometimes a set of differential equations may be required and, in this case, standard schemes like the forward Euler, backward …


Is The World Evolving Discretely?, Saber Elaydi Aug 2015

Is The World Evolving Discretely?, Saber Elaydi

Saber Elaydi

No abstract provided.


Global Stability Of Periodic Orbits Of Non-Autonomous Difference Equations And Population Biology, Saber Elaydi, Robert Sacker Aug 2015

Global Stability Of Periodic Orbits Of Non-Autonomous Difference Equations And Population Biology, Saber Elaydi, Robert Sacker

Saber Elaydi

Elaydi and Yakubu showed that a globally asymptotically stable(GAS) periodic orbit in an autonomous difference equation must in fact be a fixed point whenever the phase space is connected. In this paper we extend this result to periodic nonautonomous difference equations via the concept of skew-product dynamical systems. We show that for a k-periodic difference equation, if a periodic orbit of period r is GAS, then r must be a divisor of k. In particular sub-harmonic, or long periodic, oscillations cannot occur. Moreover, if r divides k we construct a non-autonomous dynamical system having minimum period k and which has …


Periodic Difference Equations, Population Biology And The Cushing-Henson Conjectures, Saber Elaydi, Robert Sacker Aug 2015

Periodic Difference Equations, Population Biology And The Cushing-Henson Conjectures, Saber Elaydi, Robert Sacker

Saber Elaydi

We show that for a k-periodic difference equation, if a periodic orbit of period r is globally asymptotically stable (GAS), then r must be a divisor of k. In particular sub-harmonic, or long periodic, oscillations cannot occur. Moreover, if r divides k we construct a non-autonomous dynamical system having minimum period k and which has a GAS periodic orbit with minimum period r. Our method uses the technique of skew-product dynamical systems. Our methods are then applied to prove two conjectures of J. Cushing and S. Henson concerning a non-autonomous Beverton-Holt equation which arises in the study of the response …


Nonautonomous Beverton-Holt Equations And The Cushing-Henson Conjectures, Saber Elaydi, Robert Sacker Aug 2015

Nonautonomous Beverton-Holt Equations And The Cushing-Henson Conjectures, Saber Elaydi, Robert Sacker

Saber Elaydi

In [3] Jim Cushing and Shandelle Henson published two conjectures (see Section 3) related to the Beverton-Holt difference equation (with growth parameter exceeding one), which said that the B-H equation with periodically varying coefficients (a) will have a globally asymptotically stable periodic solution and (b) the average of the state variable along the periodic orbit will be strictly less than the average of the carrying capacities of the individual maps. They had previously [2] proved both statements for period 2.


An Extension Of Sharkovsky’S Theorem To Periodic Difference Equations, Ziyad Alsharawi, James Angelos, Saber Elaydi, Leela Rakesh Aug 2015

An Extension Of Sharkovsky’S Theorem To Periodic Difference Equations, Ziyad Alsharawi, James Angelos, Saber Elaydi, Leela Rakesh

Saber Elaydi

We present an extension of Sharkovsky’s Theorem and its converse to periodic difference equations. In addition, we provide a simple method for constructing a p-periodic difference equation having an r-periodic geometric cycle with or without stability properties.


Asymptotic Stability Of Linear Difference Equations Of Advanced Type, Fozi Dannan, Saber Elaydi Aug 2015

Asymptotic Stability Of Linear Difference Equations Of Advanced Type, Fozi Dannan, Saber Elaydi

Saber Elaydi

Necessary and sufficient conditions are obtained for the asymptotic stability of difference equations of advanced typen of the form x(n) - ax(n+1) + bx(n+k) = 0, n = 0, 1, .. where a and b are arbitrary real numbers and k > 1. For a = 1, we establish an analogue of a result by Levin and May.


Basin Of Attraction Of Periodic Orbits Of Maps On The Real Line, Saber Elaydi, Robert Sacker Aug 2015

Basin Of Attraction Of Periodic Orbits Of Maps On The Real Line, Saber Elaydi, Robert Sacker

Saber Elaydi

We prove a conjecture by Elaydi and Yakubu which states that the basin of attraction of an attracting 2 k -cycle of the Ricker's map is where E is the set of all eventually 2 r -periodic points. The result is then extended to a more general class of continuous maps on the real line.


Poincaré Types Solutions Of Systems Of Difference Equations, Raghib Abu-Saris, Saber Elaydi, Sophia Jang Aug 2015

Poincaré Types Solutions Of Systems Of Difference Equations, Raghib Abu-Saris, Saber Elaydi, Sophia Jang

Saber Elaydi

No abstract provided.


Pixley-Roy Hyperspaces Of Ω-Graphs, Joe Mashburn Jul 2015

Pixley-Roy Hyperspaces Of Ω-Graphs, Joe Mashburn

Joe D. Mashburn

The techniques developed by Wage and Norden are used to show that the Pixley-Roy hyperspaces of any two ω-graphs are homeomorphic. The Pixley-Roy hyperspaces of several subsets of Rn are also shown to be homeomorphic.


Countable Covers Of Spaces By Migrant Sets, Zoltan Balogh, Joe Mashburn, Peter Nyikos Jul 2015

Countable Covers Of Spaces By Migrant Sets, Zoltan Balogh, Joe Mashburn, Peter Nyikos

Joe D. Mashburn

The motivation for this note is a paper by Hidenori Tanaka in which he shows that the Pixley-Roy hyperspace of a metric space X is normal if and only if X is an almost strong q-set.


Linearly Ordered Topological Spaces And Weak Domain Representability, Joe Mashburn Jul 2015

Linearly Ordered Topological Spaces And Weak Domain Representability, Joe Mashburn

Joe D. Mashburn

It is well known that domain representable spaces, that is topological spaces that are homeomorphic to the space of maximal elements of some domain, must be Baire. In this paper it is shown that every linearly ordered topological space (LOTS) is homeomorphic to an open dense subset of a weak domain representable space. This means that weak domain representable spaces need not be Baire.


A Comparison Of Three Topologies On Ordered Sets, Joe Mashburn Jul 2015

A Comparison Of Three Topologies On Ordered Sets, Joe Mashburn

Joe D. Mashburn

We introduce two new topologies on ordered sets: the way below topology and weakly way below topology. These are similar in definition to the Scott topology, but are very different if the set is not continuous. The basic properties of these three topologies are compared. We will show that while domain representable spaces must be Baire, this is not the case with the new topologies.