4th Seminar on Tuesday
Location: Room 114 McAllister
Time: Tuesday, Dec 07, 2010, 05:00pm~05:45pm
Speaker: Zuowei Shen, National University of Singapore
Title:
Abstract:
3rd Seminar on Tuesday
Location: Room 106 McAllister
Time: Tuesday, Nov 11, 2010, 05:00pm~05:45pm
Speaker: Peter Gael, Penn State University
Title: Applied Computational Geometry at the Army Research Laboratory (A Research Internship Perspective)
Abstract: In this talk I will discuss my experience working for the US Army Research Laboratory. In addition to some details of my own research while in their employ, I plan to comment generally on areas of Army research and on what it's like to work for the Department of Defense. Regardless of whether you want to be a professor or not, you will find this talk interesting.
Seminar Series - Fall 2010
2nd Seminar on Tuesday
Location: Room 106 McAllister
Time: Tuesday, Sep 21, 2010, 12:10pm~01:25pm
Speaker: Wen Cheng, Penn State University
Title: A novel numerical method for a class of Cauchy problems
Abstract: In this talk we consider the parabolic equations with variable coefficients in $R^n$, and provide a novel approach to compute the solutions numerically. Our method is based on the newly developed Dyson-Taylor Commutator method, which approximates the Green's function for short time analytically. However, the results can be extended to large time as well by a bootstrap scheme. We also prove explicit error estimate in weighted Sobolev spaces, and test our results numerically and compare to other known methods.
1st Seminar on Tuesday
Location: Room 106 McAllister
Time: Tuesday, Sep 07, 2010, 12:10pm~01:25pm.
Speaker: Yanxiang Zhao, Penn State University
Title: Adhesion of Two-component Vesicle Membranes
Abstract: We study the adhesion of multi-component vesicle membrane to flat/curved substrates. By introducing a phase field function, we can distinguish the different components of the vesicle membranes, and formulate the total energy in terms of phase field function to describe the equilibrium shapes of the vesicle membranes. By numerically solving the equilibrium equations (Euler-Lagrange equations), we find a number of representative membrane shapes with a variety of parameter values. We discuss the stability of the vesicle membranes enduring the adhesion, and reveal that adhesion can promote the phase separation for the vesicle membranes.
Seminar Series - Spring 2010
Seminar on Tuesday
We had the first student seminar of 2010 on
Tuesday, Mar 2nd, 2010, 12:15pm~01:30pm, at Room 114 McAllister
Speaker: Tom Manteuffel, University of Colorado
Title: What is computational mathematics?
Abstract: This talk offers a general retrospection on the development of computational instruments and the numerical algorithms. Our ability to model complex physical systems has benefited more from new mathematical algorithms than from the explosive growth in computer speed. To continue the success, we demand new algorithms that possess both algorithmic and parallel scalability, deal with complex geometry and model complex coupled systems.
Seminar on Tuesday
We have 2rd student seminar on
Tuesday, Mar 23rd, 2010, 5:00pm~6:10pm, at Room 106 McAllister
Speaker: Tao Wang, Pennsylvania State University
Title: Optimal strategy for wildfire containment
Abstract: This talk introduces a new class of variational problems for differential inclusions, motivated by the control of forest fires. To block the fire, a wall can be constructed progressively in time, at a given speed. In the research, we study the possibility of constructing a wall which completely encircles the fire. Moreover, we derive necessary conditions for an optimal strategy, which minimizes the total area burned by the fire.
Seminar on Tuesday
We have 3rd student seminar on
Tuesday, Mar 30rd, 2010, 5:00pm~6:00pm, at Room 106 McAllister
Speaker: Yuanyuan Wan, Department of Economics, Pennsylvania State University
Title: Semiparametric estimation of binary decision games of incomplete information with correlated private signals
Abstract:
Seminar on Tuesday
We have 4th student seminar on
Tuesday, Apr 06, 2010, 5:00pm~6:00pm, at Room 106 McAllister
Speaker: Andong He, Pennsylvania State University
Title: Inertial corrections to the Darcy's law for Hele-shaw flows
Abstract:
Seminar on Tuesday
We have 5rd student seminar on
Tuesday, Apr 12, 2010, 12:00pm~01:15pm, at Room 106 McAllister
Speaker: Suzanne M. Shontz, Pennsylvania State University (CSE)
Title: Derivative-Free Optimization Algorithms for Mesh Quality Improvement
Abstract: Meshes are generated for use in the numerical solution of partial differential equations (PDEs), which arise in numerous science and engineering applications. It is essential that the meshes be of high quality in that the quality of the mesh affects the PDE solution accuracy as well as the execution time and conditioning of the relevant linear solver. Mesh quality improvement is necessary when the mesh is of less than desirable quality (either from mesh generation or deformation). In the first part of my talk, I will give an introduction to mesh quality improvement. In the second part of my talk, I will describe two derivative-free methods for mesh optimization, namely the pattern search (PS) and multidirectional search (MDS) mesh quality improvement methods, to be used with nondifferential objective functions representing the overall mesh quality. Such objective functions arise when the goal of the mesh optimization problem is to improve the worst quality element in the mesh. I will present numerical results demonstrating the effectiveness of these techniques in improving the worst quality elements of several finite element meshes.
Seminar on Tuesday
We have 6rd student seminar on
Tuesday, Apr 20, 2010, 12:00pm~01:15pm, at Room 114 McAllister
Speaker: Van Cyr, Vitaliy Gyrya and Manlin Li, Pennsylvania State University
Title: How to find a job?
Abstract: For this seminar we had three speakers. Van gave a comprehensive summary on applying for PostDoc in academic institution, including application materials, important dates for application and useful web resources etc. After Van, Vitaliy outlined his personal experience finding PostDoc in national lab. At last, Manlin delivered a uplifting speech, and shared his own philosophies about hunting job in industry.
Seminar Series - Fall 2009
Seminar on Tuesday, November 17th
We will have the 6th student seminar on
Tuesday, Nov 17th, 5:00pm~6:00pm, at 106 McAllister
Speaker: Xiang Xu
Title: Global existence and asymptotic behavior of the Ericksen-Leslie system
Abstract: In this talk we will discuss the classical solutions of a hydrodynamic system modeling the nematic liquid crystal materials. This system is a coupled system of Navier-Stokes equations and kinematic transport equations for the molecular orientations. First using different energetic variational approaches, we can recover the system in different ways and distinguish the conservative and dissipative parts of the induced stress terms. Next based on a modified Galerkin method and the study of higher order energy law, we can prove the existence of global classical solutions in both 2D and 3D cases, with some extra assumptions on those viscosity coefficients. Then by a suitable Lojasiewicz-Simon type inequality, we get the convergence of solutions to a steady state solution as time goes to infinity. Moreover, an estimation of convergence rate is provided. Finally, we reveal the relation between Parodi's condition and certain stability of the system.
Seminar on Tuesday
We will have the 5th student seminar on
Tuesday, Nov 3rd, 5:00pm~6:00pm, at 106 McAllister
Speaker: Brian Haines
Title: Effective Viscosity and Dynamics of Dilute Bacterial Suspensions: A Three-Dimensional Model
Abstract: We present a Stochastic PDE model for dilute suspensions of bacteria in a three-dimensional Stokesian fluid. This model is used to calculate the statistically-stationary bulk deviatoric stress and effective viscosity of the suspension from the microscopic details of the interaction of an elongated body with the background flow. A bacterium is modeled as a prolate spheroid with self-propulsion provided by a point force, which shows up in the model as an inhomogeneous delta function in the PDE. The bacterium is also subject to a stochastic torque in order to model tumbling (random reorientation). Due to a bacterium's asymmetric shape, interactions with a prescribed generic background flow, such as pure straining or planar shear, cause the bacterium to preferentially align in certain directions. Due to the stochastic torque, the steady-state distribution of orientations is unique for a given background flow. Under this distribution of orientations, self-propulsion produces a
reduction in the effective viscosity. For sufficiently weak background flows, the effect of self-propulsion on the effective viscosity dominates all other contributions, leading to an effective viscosity of the suspension that is lower than the viscosity of the ambient fluid. This is in agreement with recent experiments on suspensions of Bacillus subtilis..