University of Wisconsin Madison College of Engineering

Upcoming Events

  1. Monday, December 1

    12:00 PM

    Engineering Physics Colloquium

    106 ERB

    Speaker: Dr. Zhijie (George) Jiao, Associate Research Scientist, University of Michigan, Ann Arbor

    "Ion Irradiation for Understanding of Neutron Radiation Damage in Reactor Materials"

    Abstract: Reactor materials in-service must withstand radiation damage accumulation to certain levels in aggressive environments. Cladding and structural materials for application in fast reactors and fusion reactors need to be structurally sound up to a damage level of hundreds of displacement per atom (dpa) at the end of life. Ion irradiation, with high damage rate, low cost and minimal sample activation, provides an ideal path for emulation of microstructure evolution under reactor radiations to very high doses. Evolution of major irradiated microstructure features including radiation-induced precipitation, radiation-induced segregation, dislocation loops, and voids in austenitic and ferritic-martensitic steels will be presented, with the focus on microstructural response at high doses. Irradiated features induced by ion beams are compared to available reactor radiation data at comparable irradiation conditions for fidelity check. The tailored ion irradiations can emulate the reactor-irradiated microstructure to a reasonable level of agreement across all the principal microstructures. The current research status using ion beams as well as the future direction of ion irradiation will be discussed.

    Bio: Dr. Zhijie (George) Jiao is currently an associate research scientist at the Department of Nuclear Engineering and Radiological Sciences at the University of Michigan, Ann Arbor. He received his B.S./M.E. in metal/materials physics from University of Science and Technology Beijing, and Ph.D in materials science from Polytechnic University, New York. Since he joined Prof. Gary Was’ research group in 2004, He has conducted extensive research in radiation effects on reactor materials and materials degradation issues such as irradiation-assisted stress corrosion cracking, resulting in over 30 peer-reviewed publications in the area. He is an expert on ion irradiations and characterization of radiation damage using TEM and APT. He is the receiver of the 2008 and 2011 Literary Award from the ANS- MSTD. He is an ORNL SHaRE User facilities and ANS -MSTD executive committee member and a regular reviewer for scientific journals and DOE proposals.

  2. Tuesday, November 25

    4:00 PM

    Engineering Physics Colloquium

    106ERB

    Speaker: Professor Mike Corradini, University of Wisconsin-Madison 

    "Advanced Nuclear Power Technology: Status and Future"

    Abstract: Nuclear science and technology has had an enormous impact in providing for the public good. With the growing demand for energy that has a minimal effect on the environment, nuclear energy represents one of the key ways to provide electrical power at any time of the day and at a competitive cost. Just as important it provides the US with a large-scale carbon-neutral power source domestically, enhancing our energy security. Nuclear power in the US remains safe, and we are enhancing the protections against extreme natural events. And most importantly, the first new generation of reactors since the 1980’s are now being built in a predictable and cost-effective manner. This talk provides a status of nuclear power in the US and worldwide and discusses issues that will affect its future.

    Bio: Michael L. Corradini is Wisconsin Distinguished Professor of Nuclear Engineering and Engineering Physics at the University of Wisconsin-Madison. He has published widely in areas related to vapor explosion phenomena, jet spray dynamics, and transport phenomena in multiphase systems.

  3. Monday, November 24

    4:00 PM

    Student visit session with Brian Albright, LANL

    514 ERB

    Our speaker for the Monday 922 seminar (11/24), Brian Albright, does plasma theory and computation at Los Alamos National Lab.  In place of the 4:00 seminar, I would like to hold a meeting for students to speak with Brian about post-graduation opportunities at LANL.  We will meet in 514 ERB, starting at 4:00 and lasting as long as the discussion goes.

  4. Monday, November 24

    12:00 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speaker: Brian Albright, LANL

    To be announced 

  5. Tuesday, November 18

    4:00 PM

    Engineering Physics Colloquium

    106 ERB

    Speaker: Brandon Deaner, Structural Analyst, Mercury Marine 

    Abstract:The midsection of an outboard marine engine experiences severe loading conditions, including high-speed impacts with submerged objects. Mercury Marine’s engineers have considered this along with other extreme load cases in order to ensure robust midsections are designed. Physical testing of the midsection components is necessary, but has several limitations, including: cost, time, equipment constraints, and the need for physical parts. However, computer simulations can help identify issues early in the design process at a greatly reduced cost. Yet, several factors make these simulations difficult, including: contact nonlinearities, plasticity, large deformations, and determining representative interactions and boundary conditions.

    This talk will discuss some of the finite element analysis (FEA) and computational fluid dynamics (CFD) simulations performed by the Design Analysis Group at Mercury Marine. Special attention is given to the midsection development and explicit dynamic impact simulations using a commercial FEA code (ABAQUS). Simulated results are compared to physical test data showing the usefulness along with the limitations of the simulation. In addition, some industry challenges which FEA analysts face will be presented along with a summary of lessons learned.

    Biography: Brandon Deaner joined the Design Analysis Group at Mercury Marine in the summer of 2013. He attended the University of Wisconsin – Madison for his undergraduate and graduate studies. Brandon received his B. S. in Engineering Mechanics and Astronautics in 2011 and his M. S. in Engineering Mechanics in 2013. As a graduate student, Brandon worked with Associate Professor Matthew S. Allen and studied the nonlinear damping associated with bolted joints. His thesis was titled “Modeling the Nonlinear Damping of Jointed Structures using Modal Models.” Brandon’s engineering related interests include: structural dynamics, topology optimization, high speed hydrodynamic instabilities, and explicit impact simulations. He also enjoys running, biking, volleyball, and attending Wisconsin sporting events.

  6. Friday, November 7

    12:00 PM

    Midwest Mechanics Seminar

    106 ERB

    Speaker: Prof. Peter Schmid, Imperial College, London

    "Adjoint-based optimization for flow analysis and flow control"

    Abstract: Over the past decade, gradient-based optimization techniques have become a common tool in the analysis of fluid systems. These techniques replace large-scale matrix decompositions and allow the generalization of classical stability and receptivity concepts towards a more flexible and powerful input-output and sensitivity framework. Gradient information is contained in the adjoint variables which arise from a variational form of an optimization problem.  Maximum energy amplification, largest frequency response and parameter sensitivities can be readily addressed within this formulation. We will show how to efficiently extract linearized and adjoint information directly from nonlinear simulation codes and how to use this information for determining common flow characteristics. We also extend this framework to deal with the optimization of less common norms. Examples from aeroacoustics and mixing will be presented to showcase the effectiveness of gradient-based flow analysis and control.

       


  7. Monday, November 3

    4:00 PM

    Engineering Physics Colloquium

    106 ERB

    Speaker: Dr. Michael R. Tonks, Microstructure Science Group Lead, Idaho National Laboratory

    "Multiscale Development of Predictive Materials Models Applied to Light Water Reactor Fuel Performance"

    Abstract: Nuclear energy is a critical part of our Nation’s energy future, but future reactors may look very different from our current fleet of light water reactors (LWRs). Various new reactor concepts are currently being considered, including accident tolerant LWR fuel, small modular reactors, and next generation nuclear plants. The development of these new reactor concepts can be accelerated by the development of predictive modeling and simulation capabilities that couple fuel performance, thermal fluids, and reactor physics. INL’s MOOSE framework is a powerful tool for the development of these multiphysics simulation tools.

    A critical aspect of these simulation tools must be the development of mechanistic materials models that, once validated, can predict material behavior in a range of conditions. I am using multiscale modeling and simulation and experiments to develop predictive materials models for reactor applications. I demonstrate this approach by showing how we are replacing the legacy empirical materials models used in fuel performance codes with mechanistic models that are based on microstructure rather than burn-up. I specifically show our UO2 model development efforts in the areas of grain growth, cracking, fission gas release, and thermal conductivity. This work was funded by the US Nuclear Energy Advanced Modeling and Simulation program and by internal INL funding.

    Bio: Dr. Michael R Tonks is the Computational Microstructure Science group lead in the Nuclear Fuels and Materials Division at Idaho National Laboratory, where he has worked since 2008. He received his Ph.D. in Mechanical Engineering from the University of Illinois at Urbana-Champaign in 2008. His main research area is using mesoscale computational approaches to predict the coevolution of microstructure and physical properties, and is the lead developer of INL’s mesoscale MARMOT code and two physics modules in the MOOSE framework. He has helped to pioneer the development of improved materials models for LWR fuel performance using multiscale modeling and simulation. He received multiple Laboratory Director’s awards at INL and received the TMS Structural Materials Division Young Leader Professional Development Award.

  8. Tuesday, October 28

    4:00 PM

    Engineering Physics Colloquium

    106 ERB

    Speaker: Brendan Kochunas, Assistant Research Scientist, University of Michigan

    "Frontiers in High Fidelity Simulations of Light Water Reactors"

    Abstract: This seminar will discuss the advances in Light Water Reactor (LWR) simulations during the past 10 years. The traditional industry approach used to design and analyze the majority of today's operating reactors will first be briefly described to provide a context for the next generation of high fidelity methods being developed today. The most important simulation capabilities and their value to the research community will be discussed within the context of the work being done by Consortium for the Advanced Simulation of LWRs (CASL), the DOE's nuclear modeling and simulation hub. Finally, the near and long term challenges facing researchers in the area of high fidelity computational reactor physics are presented and discussed along with the broader impacts that this research may have in the area of scientific computing.

    Bio: Brendan Kochunas has been working in the field of computational reactor physics since 2004 when he began work as an undergraduate with Professor Tom Downar at Purdue on the whole core neutron transport DeCART as part of INERI collaboration with ANL and KAERI. In 2009, Dr. Kochunas began his PhD research at the University of Michigan on the 3D method of characteristics. The MPACT code grew out of his PhD research and this past year MPACT was chosen to be the neutronics simulator of the VERA-CS core simulator for CASL. In 2011 Dr. Kochunas was awarded the inaugural CASL "Knight Award" as the technical contributor of the year for his contributions to the CASL project. 

    PhD, Nuclear Engineering, University of Michigan, 2013 

    MSE, Nuclear Engineering, University of California Berkeley, 2008 

    BS, Nuclear Engineering, Purdue University, 2006

  9. Tuesday, October 21

    4:00 PM

    Engineering Physics Colloquium

    106 ERB

    Speaker: Shannon M. Bragg-Sitton, Idaho National Laboratory

    "Integrated Nuclear – Renewable Energy Systems Development"

    Abstract: The U.S. Department of Energy (DOE) recognizes the need to transform the energy infrastructure of the U.S. and elsewhere to systems that can significantly reduce environmental impacts in an efficient and economically viable manner while utilizing both hydrocarbon resources and clean energy generation sources. Thus, DOE is supporting research and development that could lead to more efficient utilization of clean energy generation sources, including renewable and nuclear options. A concept being advanced by the DOE Offices of Nuclear Energy (NE) and Energy Efficiency and Renewable Energy (EERE) is tighter coupling of nuclear and renewable energy sources in a manner that better optimizes energy use for the combined electricity, industrial manufacturing, and the transportation sectors. This integration concept has been referred to as a “hybrid system” that is capable of providing energy (thermal or electrical) where it is needed, when it is needed. For the purposes of this work, the hybrid system would integrate two or more energy resources to generate two or more products, one of which must be an energy commodity, such as electricity or transportation fuel. This definition requires coupling of subsystems ‘‘behind’’ the electrical transmission bus, where energy flows are dynamically apportioned as necessary to meet demand and the system has a single connection to the grid that provides dispatchable electricity while capital intensive generation assets operate at full capacity. This presentation will provide an overview of the integrated energy system concept, technical gaps and challenges that must be addressed, and candidate region-specific opportunities and system configurations.

    Bio: Dr. Bragg-Sitton is a Senior Nuclear Engineer at Idaho National Laboratory in the Nuclear Science & Technology Directorate, Nuclear Fuels & Materials Division. Her education includes a Bachelor of Science in Nuclear Engineering from Texas A&M University; a Master of Science in Medical Physics from the University of Texas at Houston; and a Masters and Ph.D. in Nuclear Engineering from the University of Michigan. Dr. Bragg-Sitton currently serves in various leadership positions within Department of Energy programs related to advanced nuclear fuel development and advanced nuclear systems implementations.

    Within the Fuel Cycle Research and Development (FCRD) Program, Shannon is the Deputy National Technical Director for the Advanced Fuels Campaign (AFC). AFC encompasses research in advanced light water reactor fuels, with a recent focus on the development of accident tolerant fuels; transmutation fuels; cross-cutting capability development; and advanced fuel performance modeling and simulation.

    Within the Advanced Reactor Technologies (ART) Program, Shannon is the Co-Lead for Nuclear Hybrid Energy Systems Development, which proposes to tightly couple nuclear and renewable generation systems to produce both electricity and an additional commodity that may require thermal and/or electrical energy input to drive the process. Programmatic interest in this research area has recently increased in recognition of the need to think differently about energy systems of the future.

  10. Monday, October 20

    12:00 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speakers: Oliver Schmitz, UW And Gavin Weir, UW

    APS rehearsals


    Oliver Schmitz, UW

    "Impact of the plasma response in three-dimensional edge plasma transport modelling for RMP ELM control scenarios at ITER"

    Abstract: The constrains used in magneto-hydrodynamic (MHD) modeling of the plasma response to external resonant magnetic perturbation(RMP) fields have a profound impact on the three-dimensional (3-D) shape of the plasma boundary induced by RMP fields. In thiscontribution, the consequences of the plasma response on the actual 3D boundary structure and transport during RMP application atITER are investigated. The 3D fluid plasma and kinetic neutral transport code EMC3-Eirene is used for edge transport modeling. Plasmaresponse modeling is conducted with the M3D-C1 code using a single fluid, non-linear and a two fluid, linear MHD constrain. These approaches are compared to results with an ideal MHD like plasma response. A 3D plasma boundary is formed for all cases consisting of magnetic finger structures at the X-point intersecting the divertor surface in a helical footprint pattern. The width of the helical footprintpattern is largely reduced compared to vacuum magnetic fields when using the ideal MHD like screening model. This yields increasing peakheat fluxes in contrast to a beneficial heat flux spreading seen with vacuum fields. The particle pump out as well as loss of thermal energy isreduced by a factor of two compared to vacuum fields. In contrast, the impact of the plasma response obtained from both MHD constrainsin M3D-C1 is nearly negligible at the plasma boundary and only a small modification of the magnetic footprint topology is detected.Accordingly, heat and particle fluxes on the target plates as well as the edge transport characteristics are comparable to the vacuumsolution. This span of modeling results with different plasma response models highlights the importance of thoroughly validating both,plasma response and 3D edge transport models for a robust extrapolation towards ITER.


    Gavin Weir, UW

    "Comparison of Measurements of Profile Stiffness in HSX to Nonlinear Gyrokinetic Calculations"

    Abstract: Tokamaks and stellarators have observed significant differences in profile stiffness, defined as the ratio of the transient thermal diffusivity obtained from heat pulse propagation to the diffusivity obtained from steady-state power balance. Typically, stellarators have measured stiffness values below 2 and tokamaks have observed stiffness greater than 4. In this paper we present the first results on stiffness measurements in the quasihelically symmetric experiment HSX in which the neoclassical transport is comparable to that in a tokamak and turbulent transport dominates throughout the plasma. Electron Cyclotron Emission (ECE) is used to measure the local electron temperature perturbation from modulating the ECRH system on HSX. Spectral analysis of the ECE data yields a profile of the perturbed amplitude and a resulting transient electron thermal diffusivity that is close to the steady-state diffusivity. This evidence of a lack of stiffness in HSX agrees with the scaling of the steady-state heat flux with temperature gradient. The experimental data is compared to gyrokinetic calculations using the GENE code with two kinetic species. Linear calculations demonstrate that the Trapped Electron Mode (TEM) is the dominant long-wavelength microturbulence instability with growth rates that scale linearly with electron temperature gradient. Nonlinear gyrokinetic flux tube simulations indicate that the TEM contributes significantly to the saturated heat fluxes in HSX, shifting the transport-carrying wavenumbers to larger values than in typical Ion Temperature Gradient (ITG) turbulence. A set of nonlinear simulations are being executed, examining the saturated nonlinear heat flux as a function of the electron temperature gradient, to obtain a stiffness value from the simulations to compare with experimental results.

    Full abstracts for each speaker can be found here:

     http://www.cptc.wisc.edu/reports/Oliver-Schmitz_and_Gavin-Weir_abstracts_Oct20_2014.pdf

  11. Tuesday, October 14

    4:00 PM

    Engineering Physics Colloquium

    106 ERB

     Speaker: David Rothamer, University of Wisconsin-Madison, ME Department

    "Development and Application of Phosphor Thermography for Measurements in Combustion Systems"

    Abstract: Thermographic phosphors are composed of active ions doped into crystalline materials. The temperature dependence of their emission makes them useful as in situ sensors of local temperature in a variety applications. For combustion systems, temperature is a key parameter as it controls reaction rates and impacts heat losses. Seeding of micron-sized thermographic phosphor particles to enable simultaneous temperature and velocity measurements has been successfully demonstrated at low to moderate temperatures in gaseous flows. However, high rates of non-radiative relaxation at high temperatures makes achieving precise measurements in combustion environments a major challenge. This talk will review general background on thermographic phosphor measurements, first highlighting previous measurement at moderate temperatures. The challenges of applying the technique at higher temperatures with sufficient time resolution will be explored, and ongoing work to achieve these goals will be discussed. Potential future applications of the technique will also be presented.

    Bio: Prof. Rothamer is an associate professor in the Mechanical Engineering department at the University of Wisconsin-Madison. He is a principal investigator in the Engine Research Center (ERC) and is also a member of the Great Lakes Bioenergy Research Center. Rothamer received his PhD from Stanford University in 2008. Prior to his work at Stanford, he received his BS and MS from the University of Wisconsin-Madison. Rothamer was a recipient of the Masao Horiba award in 2008 given by Horiba Ltd. to young scientists who are devoting themselves to research and development of innovative technologies in analysis and measurement. In 2012, Rothamer received an NSF CAREER award to support research in the area of advanced temperature imaging diagnostics using thermographic phosphors with application to low temperature combustion in IC engines. Prof. Rothamer’s research is focused on problems involving fluid mechanics, chemical kinetics, and combustion, including: the design of alternative fuels and impact of fuel chemistry and properties on IC engine performance and emissions, understanding the fundamental mechanisms of soot formation in IC engines, and designing and applying advanced laser-based imaging diagnostics to study fundamental combustion problems and practical combustion systems.

  12. Monday, October 13

    4:00 PM

    Plasma Theory Seminar

    514 ERB

    Speaker:  Aaron Bader, UW

    "Multivariable Optimization Techniques Applied to HSX Coil Generation"

  13. Friday, October 10

    12:00 PM

    Midwest Mechanics Seminar

    106 ERB

    Speaker: Prof. Charles Meneveau, Johns Hopkins University

    "Turbulence in wind farm boundary layers"

    Abstract: Similar to other renewable energy sources, wind energy is characterized by low power density. Hence, in order for wind energy to make a significant contribution to our overall energy supply, large wind farms (on or off-shore) need to be envisioned. As it turns out, not much is known about the interactions between large wind farms and the atmospheric boundary layer. A case in point, as wind farms are getting larger, operators have begun to complain about the so-called "wind-farm underperformance" problem. This presentation will summarize our results that focus on understanding how wind turbines, when deployed in large arrays, extract kinetic energy from the atmospheric boundary layer. Large Eddy Simulations (LES) are used to improve our understanding of the vertical transport of momentum and kinetic energy across a boundary layer flow with wind turbines. A suite of LES, in which wind turbines are modeled using the classical `actuator disk' concept, are performed for various wind turbine arrangements, turbine loading factors, and surface roughness values. The results are used to develop improved models for effective roughness length scales and to obtain new optimal spacing distances among wind turbines in a large wind farm. We introduce the notion of generalized transport tubes as a new tool for flow visualization that is particularly useful to analyze the spatial transport of particular physical quantities (e.g. kinetic energy arriving at a particular wind turbine). Finally, we introduce a new engineering model, the Coupled Wake Boundary Layer model that reconciles wake expansion/superposition models currently used in industry with the vertical structure of the atmospheric boundary layer. This work is a collaboration with colleagues, postdocs and students involved in the WINDINSPIRE project and is supported by the US National Science Foundation.

    The full brochure can be found below:

    Meneveau_Flier_101014.pdf

  14. Monday, October 6

    12:00 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speaker: Stuart Hudson, Princeton Plasma Physics Laboratory

    "Chaotic coordinates for the Large Helical Device"

    Abstract: http://w3.pppl.gov/~shudson/Papers/Conference/2014ITC/HudsonITCabstract.pdf

  15. Monday, September 29

    12:00 PM

    Plasma Physics Seminar

    2535 Engineering Hall

     Speaker: Vadim Roytershteyn, Space Science Institute

    "Coherent structures and magnetic reconnection in collisionless turbulence from the perspective of kinetic particle simulations"

  16. Friday, September 26

    12:00 PM to 1:00 PM

    Midwest Mechanics Seminar

    106 ERB

    Speaker: Professor Robert W. Carpick, University of Pennsylvania

    Abstract: I will discuss recent atomic force microscopy studies of nanoscale single asperity contacts that reveal surprising new behavior and insights. First, the behavior of nanoscale contacts with truly 2-dimensional materials will be discussed. For nanoscale contacts to graphene, we find that the friction force exhibits a significant dependence on the number of 2-D layers [1]. An even stronger effect occurs when graphene is fluorinated, where experiments and simulations both show that friction between nanoscale tips and fluorinated graphene (FGr) monolayers exceeds that for pristine graphene by an order of magnitude. The results can be interpreted in the context of the Prandtl-Tomlinson model of stick-slip friction [2].

    I will then discuss new insights into the physics of nanoscale wear. A better understanding of wear would allow the development of rational strategies for controlling it at all length scales, and would help enable applications for which wear is a primary limitation such as micro-/nano-electromechanical systems (MEMS/NEMS). We have demonstrated the ability to characterize single-asperity wear with a high degree of precision by performing in-situ wear tests inside of a transmission electron microscope. For silicon probes slid against a flat diamond substrate, the shape evolution and volume loss due to wear are well described by kinetic model based on stress-assisted chemical bonding mechanisms [3]. This allows new insights to be gained about the kinetics of atomic-scale wear [4].

    Bio: Robert Carpick is John Henry Towne Professor and Chair, Dept. of Mechanical Engineering and Applied Mechanics, University of Pennsylvania. Previously, he was a faculty member at the University of Wisconsin-Madison (2000-2007). He received his B.Sc. from the University of Toronto (1991), and his Ph.D. from the University of California at Berkeley (1997), both in Physics, and was a postdoc at Sandia National Laboratory (1998-1999). He studies nanotribology, nanomechanics, and scanning probes. He is the recipient of a NSF CAREER award (2001), the ASEE Outstanding New Mechanics Educator award (2003), the ASME Newkirk award (2009), an R&D 100 Award (2009), and is a Fellow of the American Physical Society and the AVS. He holds 3 patents and has authored over 100 peer-reviewed journal publications.

    [1] Lee, C., Li, Q., Kalb, W., Liu, X.-Z., Berger, H., Carpick, R.W. and Hone, J. "Frictional Characteristics of Atomically-Thin Sheets," Science, 328, 2010, 76-80.

    [2] Li, Q., Liu, X. Z., Kim, S. P., Shenoy, V. B., Sheehan, P. E., Robinson, J. T. and Carpick, R. W. “Fluorination of graphene enhances friction due to increased corrugation,”. Nano Letters, published on line (2014). DOI: 10.1021/nl502147t.

    [3] Jacobs, T.D. and Carpick, R.W. "Nanoscale Wear as a Stress-Assisted Chemical Reaction," Nature Nanotech., 8, 2013, 108-112.

    [4] Jacobs, T.D., Gotsmann, B., Lantz, M.A. and Carpick, R.W. "On the Application of Transition State Theory to Atomic-Scale Wear," Tribol. Lett., 39, 2010, 257-271

  17. Monday, September 8

    4:00 PM

    Plasma Theory Seminar

    514 ERB

    Speaker: Eric Howell, UW

    "A parametric study of extended MHD effects on interchange modes in spheromak equilibria"

  18. Monday, September 8

    12:00 PM

    Plasma Physics Seminar

    1025 Engineering Centers Building

    Speaker: Dr. John Edwards

    Lawrence Livermore National Laboratory

    Location: 1025 Engineering Centers Building (ECB)

    *********************

    Informal discussion

    11am Tuesday September 9 in 1307 Engineering Research Building (ERB)

    Students and postdoctoral associates: We have scheduled an informal discussion meeting for you with Dr. Edwards. It will be held Tuesday, September 9, 11:00 AM - 12 noon in 1307 Engineering Research Building. This session will provide a chance to ask about career opportunities at the National Ignition Facility and to discuss broader scientific questions regarding high-energy-density research.

    *****************************************************************************

    Biography: Dr. John Edwards, associate NIF director for inertial confinement fusion (ICF) and high-energy-density (HED) science, has been responsible for defining the direction of ICF and HED experiments on NIF. Dr. Edwards has more than 20 years of experience in laser-driven ICF target physics and laboratory HED physics. He earned his Ph.D. in 1990 from Imperial College in London. During his graduate study, he conducted laser plasma physics experiments and developed an interest in simulation.

    Dr. Edwards then joined the UK's Atomic Weapons Research Establishment as a HED experimental designer. He later served as the group leader for HED physics and was responsible for defining research directions. He joined the Weapons and Complex Integration Directorate at LLNL in 1998, and over the next five years, laid much of the foundation for the HED laser program in place today. Dr. Edwards then turned his focus almost entirely to ICF, leading groups in most aspects of the target physics, and later serving as the ignition team leader.


  19. Monday, April 28

    12:00 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    SpeakerProf. Huishan Cai, University of Science and Technology of China

    "Influence of energetic ions on resistive wall mode in reversed field pinch"

    AbstractA stability analysis of the circulating energetic ions (CEIs) on resistive wall mode is carried out in the reversed field pinch (RFP). In contrast to the minor resonant effects of CEI on resistive wall mode (RWM) in tokamak, the resonant interaction between RWM and CEI is important for high toroidal mode number in RFP with high beta value. The resonance provides an energy dissipation channel of free energy, and stabilizes RWM. As the fraction of CEI is large enough, the RWM is fully suppressed by CEI in the low plasma rotation, even vanishing rotation. Further, a possibility to suppress the RWM by CEI is suggested.


  20. Monday, April 14

    12:00 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker: Slava Lukin  

    "Study of magnetic reconnection in the fluid regime: The variety of environments and outcomes"

  21. Monday, April 7

    12:00 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker: Bob Kirkwood, LLNL
    "The Plasma Physics of Fusion Indirectly Driven with a Laser"

  22. Monday, March 31

    12:00 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker: Dennis Whyte, MIT
    "Exploring Boundary plasma and PMI research at MIT with new diagnostics and experiments"

  23. Wednesday, February 26

    4:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Elia Merzari, Argonne National Laboratory
    "High fidelity simulations: what can supercomputing do to improve our understanding of flow physics?"

    Abstract: In this talk, we will examine how emerging technology is allowing researchers to perform multi-physics simulations of nuclear systems with an increasing degree of resolution and accuracy. Some recent achievements will be discussed that include a fully coupled three-dimensional thermal-hydraulics, neutronics and structural mechanics simulation for a sodium fast reactor. Our focus however will be on HPC-based computational fluid dynamics, which has been recently able to tackle an increasing number of real world engineering problems. These techniques, namely large eddy simulation (LES) and direct numerical simulation (DNS), require very minimal empirical modeling and rely largely on first principles to resolve the flow field. While largely relegated to academia in the past, as supercomputing progresses, such approaches will become accessible for a much larger portion of industrial flows. The potential increased accuracy and reduction in uncertainty will definitely benefit some particular application but it should not be understood as the main potential of these approaches. In fact, they represent an invaluable window in the flow physics, especially when used in conjunction with advanced methods such as linear stability analysis, adjoint based stability analysis, proper orthogonal decomposition, wavelet analysis, quadrant analysis etc... They can also be used to compute turbulence "budgets", to provide insight into turbulence modeling improvement. The knowledge obtained through these "numerical experiments", complements the irreplaceable knowledge gained by physical experiments. In the present talk we will examine how these methods have helped us gaining a much deeper understanding of the flow physics in variety of geometries, with a particular focus on the flow in fuel assemblies.

    Biography: Dr. Elia Merzari currently works at Argonne National Lab since 2009, with a joint appointment at the Nuclear Engineering Division and the Math and Computer Science Division. Prior to joining Argonne, Elia was a Postdoctoral Fellow at the Tokyo Institute of Technology. He received his B.S. in Engineering of Energy Systems and his M.S. in Nuclear Engineering from Milan Polytechnic University in Italy and his Ph.D. in Nuclear Engineering from Tokyo Institute of Technology.

  24. Monday, February 24

    12:00 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker: Scott Baalrud, University of Iowa
    "Transport Properties of Strongly Coupled Plasmas"

  25. Monday, February 17

    12:00 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker: Mark Hermann, Sandia National Laboratory
    "Using Magnetic Fields to Create and Control High Energy Density Matter"

  26. Monday, February 17

    12:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Phil Edmondson University of Oxford
    "Any Old Ion-Characterization Radiation Damage in Nuclear Materials"

    Abstract: As we continue to develop fission and fusion based reactors, one of the most challenging problems is the choice of materials for the core. Can materials be designed that are capable of withstanding the harsh environments of a reactor? Within the reactor core intense, energetic neutrons/atoms can interact with materials giving rise to modifications in the materials’ structure. This can take the form of either permanent displacement of the lattice atoms of the material, gas bubble formation from fission gas, or via transmutation effects during which impurities may form. Microstructural changes such as these have detrimental effects on the mechanical performance of the materials through embrittlement, phase stability or swelling. As a result it is critical that a thorough understanding of the behaviour of materials under irradiation is required, such that improved predictions can be made on the performance of materials in service. In order to achieve this on laboratory timescales, ion irradiation is commonly used as a proxy for neutron irradiation. In this presentation I will discuss ion-beam-induced radiation effects in two classes of advanced materials for nuclear applications: nanocrystalline binary oxide ceramics, and nanostructured ferritic alloys (NFAs). It will be shown that the nanocrystalline oxides subjected to heavy ion irradiation undergo grain growth due to defect-stimulated growth. Examination of interfaces (grain boundaries etc) within the material will also be presented with a focus on chemical and structural behaviour under irradiation. A combined transmission electron microscope (TEM) and atom probe tomography (APT) study of the nucleation and accumulation of He bubbles in an NFA will also be discussed. Particular attention will be paid to the distribution of the bubbles throughout the matrix and to microstructural traps such as grain boundaries and dislocations. It will also be shown that APT provided the first direct experimental evidence for He bubbles being trapped within the ultra-high density fine-scale clusters distributed throughout the matrix.

    Biography: Phil is currently an EPSRC Fellow in Nuclear Materials at the University of Oxford. His main research interest lies in the microstructural evolution of materials following irradiation with heavy ions and inert gas ions. This is achieved through a combination of transmission electron microscopy, including ion irradiations in situ of the microscope, and atom probe tomography. He is currently focusing on the role of defect microstructures and nanocluster precipitates and their role in the capturing of helium, and subsequent response under displacing irradiation, in ODS steels and tungsten alloys for use in the nuclear industry as part of the Materials for Fusion and Fission project.

  27. Friday, February 14

    12:00 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker: Hui Li, Los Alamos National Laboratory
    "Particle Acceleration during Relativistic Magnetic Reconnection in a Highly Magnetized Plasma"

    Abstract: Particle energization in astrophysical systems is a challenging yet fascinating subject. Observations from radio to gamma-rays of AGN jets, supernova remnants, pulsars, gamma-ray bursts, etc., have provided important clues. In this talk, we explore the energy conversion processes in a parameter regime when the magnetic energy density overwhelms the particle energy density (including its rest mass energy density). Such a condition has been discussed in the context of AGN jets and pulsars. We present two-dimensional and three-dimensional relativistic, full kinetic simulations that show fast magnetic reconnection can occur in highly magnetized plasmas, with the magnetization parameter ranging from unity to 1600. The fast magnetic dissipation leads to a fast, nonthermal particle acceleration, yielding a power law distribution with a hard spectrum. Detailed analyses show that the acceleration in the power-law range is mainly by a Fermi-like mechanism in the relativistic flows generated by reconnection. Implications for observations will be discussed.

  28. Monday, February 10

    12:00 AM

    Engineering Physics Department Colloquium

    106 Engineering Research Building

    Speaker: Jacob Notbohm Harvard School of Public Health
    "Mechanics of cell-matrix interactions in three dimensions"

    Abstract: The forces cells apply to their surroundings control biological processes such as growth, adhesion, development, and migration. Experimental techniques to quantify cellular forces have primarily focused on measuring tractions applied by cells to synthetic two-dimensional substrates, which do not mimic in vivo conditions. While recent work has begun to quantify cell tractions in a three-dimensional (3D) environment, cell-induced forces have not yet been measured in a natural fibrous matrix. Drawing on a combination of microscopic measurements of cell and matrix kinematics, direct imaging of micro-structural changes within the matrix, and a mechanical model for the matrix fibers, I will present a new set of experimental techniques for quantifying the mechanical interactions between cells and the surrounding matrix. I will apply these experimental techniques to two mechanical problems in cell biology. First, I will discuss cell division, wherein a mother cell splits into two daughter cells. In a 3D environment, dividing cells apply tensile force to the matrix fibers through thin, persistent extensions that in turn direct the orientation and location of the daughter cells. Second, I will describe a new physical mechanism for long range cell interactions that results from nonlinearity within a fibrous matrix.

    Biography: Dr. Jacob Notbohm’s research focuses on applying principles of mechanics of materials and applied mathematics to understand how physical interactions between cells and their surroundings control bio-logical processes such as migration, division, adhesion, and invasion. To conduct this interdisciplinary research, Jacob uses a range of experimental and theoretical tools such as high resolution microscopy, digital image correlation, atomic force microscopy, mi-cropipette aspiration, magnetic tweezers, analytical solutions, and finite element models. Dr. Notbohm is currently a postdocoral research fellow at the Harvard School of Public Health. He received his Ph.D. from the California Institute of Technology in Mechanical Engineering in 2013 and his B.S. from the University of Wisconsin in Engineering Mechanics in 2007.

  29. Monday, February 3

    12:00 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker:  Ivan Khalzov, University of Wisconsin - Madison
    "Theoretical foundations for the Plasma Dynamo Experiment"

  30. Friday, January 31

    12:05 PM

    Midwest Mechanics Seminar

    106 Engineering Research Building

    Speaker: Professor Ellen Kuhl, Stanford University
    "Extreme Mechanics of Growing Matter"

  31. Thursday, January 30

    4:00 PM to 6:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Julie Tucker Oregon State University
    "Microfabricated Expandable Sensor Networks for Intelligent Structures"

    Abstract: The development of long range ordered phases in Ni-Cr alloys can degrade material properties and is a potential concern for nuclear power systems. The ordering rate and the factors that influence it need to be better understood to predict behavior of Ni-Cr alloys during long term service at intermediate temperatures. In order to quantify the ordering kinetics, we apply a combined computational-experimental approach on model alloys, with Ni/Cr atomic ratios near 2:1. Isothermal agings were conducted at temperatures between 333°C-470°C for times up to 10,000 hours. The effects of alloying (0-9 wt.% Fe), cold work and excess vacancies were investigated and ordering was assessed by changes in the lattice parameter and hardness. Kinetic Monte Carlo simulations and experiments show that ordering is well described by Kolmogorov-Johnson-Mehl-Avrami kinetics. Solute-vacancy interactions of common alloying elements (Mo, Mn, Si, and Nb) were investigated via first-principles to better understand ordering in complex engineering alloys.

    Biography: Dr. Tucker earned her B.S. in Nuclear Engineering from the University of Missouri – Rolla. She attended graduate school at the University of Wisconsin – Madison as a Naval Nuclear Propulsion Fellow, where she received her M.S. and Ph.D. in Nuclear Engineering with an emphasis in Materials Science in 2008. After graduation, Dr. Tucker spent five years as a Principal Scientist at Knolls Atomic Power Laboratory (KAPL) in Schenectady, NY studying the thermal stability of structural alloys for nuclear power systems. She recently joined the Mechanical, Industrial, and Manufacturing Engineering department at Oregon State University as an Assistant Professor. Her research efforts are focused on nuclear materials and metallurgy and leverage both modeling and experimental approaches to gain fundamental understanding of materials degradation mechanisms.

  32. Monday, January 27

    12:00 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker:  Tom Intrator, LANL
    "Two LANL Laboratory Astrophysics Experiments"

  33. Wednesday, January 22

    12:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Dr. Tevis Jacobs, University of Pennsylvania
    "Microfabricated Expandable Sensor Networks for Intelligent Structures"
    Abstract: The atomic-scale mechanics, chemistry, and physics that govern the adhesion and wear of surfaces in contact are not well understood. Yet accurate description and prediction of such contact phenomena is critically important in advanced nanoscale applications, including micro-/nano-electromechanical systems (e.g., actuators, switches), nanomanufacturing processes (e.g., dip-pen nanolithography), and microscopy applications (e.g., nanoscale mapping of mechanical properties). In this work, nanoscale adhesion and wear tests were performed inside of a transmission electron microscope (TEM) using a commercial nanoindenter that was modified to enable contact between a flat diamond punch and the sharp nanoscale tip of an atomic force microscope (AFM) probe. This setup enables in situ interrogation of a contact interface while controlling the displacement of the two bodies and measuring normal forces with sub-nanonewton resolution. Quantitative data were extracted using custom analysis routines to resolve the geometry of the contacting bodies, adhesive forces, and volumes removed due to wear, all with unprecedented resolution. In the first part of the talk, TEM adhesion tests of carbon-based coatings on diamond performed using this setup will be discussed. Sub-nanonewton force resolution was paired with Angstrom-scale measurements of asperity geometry. Combined with complementary molecular dynamics simulations, these results revealed an order-of-magnitude eduction in apparent work of adhesion as tip roughness increased from atomic-scale corrugation to a root-meansquare value of 1 nm. These results demonstrate the strong effect of sub-nanoscale topography on adhesion, and highlight a key limitation of conventional approaches for measuring the work of adhesion. In the second part of the talk, in situ wear tests of silicon tips sliding on diamond at low applied loads reveal that wear occurs by atomic attrition: gradual material removal at the atomic scale. The process can be accurately described using stress-assisted chemical reaction kinetics. The activation parameters extracted from this approach are physically reasonable, and constitute the first direct validation of the atomic attrition process. This framework can be generalized to understand and potentially predict wear in many materials undergoing atomic attrition, and suggests strategies for rationally testing and choosing materials for improved wear resistance.
    Biography: Dr. Tevis Jacobs received his B.Sc. at the University of Pennsylvania with a double major in Mechanical Engineering and Materials Science and Engineering. He went on to receive an M.Phil. in Computer Modeling of Materials from the University of Cambridge, and an M.Sc. in Materials Science and Engineering from Stanford University. During his undergraduate and Masters’ studies, he conducted experimental and modeling investigations into mechanical failure in a variety of materials including bulk metallic glasses, superalloys for aerospace applications, and advanced dielectric materials for semiconductor devices. He then worked for two years in Research and Development at Animas Corporation, a Johnson & Johnson company. Dr. Jacobs obtained his Ph.D. from the University of Pennsylvania, working in the group of Prof. Robert Carpick. His doctoral research focused on the investigation of the fundamentals of nanoscale adhesion and sliding wear using quantitative in situ transmission electron microscopy. He is currently a Post-Doctoral Researcher in the group of Prof. Carpick, investigating failure mechanisms in disordered materials. He received a Graduate Student Gold Award from the Materials Research Society’s Graduate Student Award competition, and is the recipient of the Dorothy M. and Earl S. Hoffman Scholarship Award from the American Vacuum Society.

  34. Thursday, January 16

    12:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

     Speaker: Dr. Yuhang Hu, Harvard University
    "Poroelastic Materials: From Fundamental Mechanics to Novel Applications"
    Abstract: Poroelastic material is a two-phase system consisting of a porous solid skeleton filled with liquid. The poroelasticity was originally developed for studying the consolidation of soils. In this study, I explore its applicability on polymeric gels, which are composed of cross-linked polymer networks swollen in an aqueous solution. Gels have broad applications in many engineering fields, but are difficult to characterize through mechanical tests because of their soft and brittle characters. Among various testing methods, indentation is recognized as the most practical technique. However, interpreting data from indentation measurement is not trivial. In this talk, I will show that within the theory of poroelasticity, the force relaxation curves from indentation can be obtained in remarkably simple forms, enabling indentation to be used with ease as a method for determining the elastic constants and diffusivity of gels. Besides material characterization, I also explore the novel applications of poroelastic materials. In one example, I will show that the surface topography of a poroelastic material can be continuously tuned from a perfectly smooth one to a rough one due to the liquid's ability to flow and configure in response to the matrix deformation. In particular, I will demonstrate simultaneous control of the material's transparency and its ability to continuously manipulate various low-surface-tension droplets from free-sliding to pinned. In another example, I will show that the liquid's ability to flow and reconfigure also provides a unique gating mechanism. The micro pores of a poroelastic membrane can be se lectively opened and closed for gas and liquid transport while the liquid layer coating around the pores almost completely prevents fouling inside the pores. These novel properties of poroelastic membranes can benefit many industrial and biomedical applications.
    Biography: Dr. Yuhang Hu is currently a postdoctoral fellow In Wyss Institute of Bioinspired Engineering and School of Engineering and Applied Sciences at Harvard working with Professor Joanna Aizenberg. She received her bachelor's degree from the Department of Engineering Mechanics at Shanghai Jiao Tong University, China in 2005, and master's degree in Mechanics and Structures from the Department of Civil and Environmental Engineering at Nanyang Technological University, Singapore In 2007. She obtained her Ph.D. in Solid Mechanics from Harvard University working with Professor Zhigang Suo and Professor Joost Vlassak In 2011. Dr. Hu's research focuses on the mechanics of soft materials and bioinspired materials. Her study involves analytical and numerical modeling, mechanical tests, materials design, and fabrication.

  35. Wednesday, January 8

    2:00 PM

    Special Plasma Seminar

    503 Engineering Research Building

    Speaker: Tom Bird, IPP-Greifswald
    "Turbulent transport in non-axisymmetric magnetic geometry"
  36. Monday, December 16

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Brendan Lyons, Princeton Plasma Physics Lab
    "A new electron drift-kinetic equation solver for coupled neoclassical-magnetohydrodynamic simulations"

  37. Tuesday, December 10

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Dr. Nathan Salowitz, Stanford University
    "Microfabricated Expandable Sensor Networks for Intelligent Structures"
    Abstract: Recently there has been significant interest in intelligent materials and structures for feedback control of autonomous aerospace systems and robotics. Many challenges exist in creating and deploying the sensors and systems to create intelligent structures without substantial parasitic side effects. Micro-fabricated expandable sensor networks address many of the issues. These networks leverage nonstandard C-MOS micro and nano-fabrication techniques, like those used to create billions of transistors on a microchip, to mass fabricate integrated networks of micro-small scale sensors and then deploy them over areas on the order of square meters. The small scale of the components creates the potential to integrate them into structures in bond lines, replacing scrims, or between lamina in a composite material. The scales, techniques, and materials used to create these networks present many challenges and opportunities in system design and fabrication. This seminar will review several of the sensors and systems that have been created on stretchable networks, fabrication challenges, and new designs for more efficient devices.
    Biography: Nathan Picchietti Salowitz received the B.S. degree in Engineering Mechanics from The University of Wisconsin - Madison and the M.S. and Ph.D. degrees in Aeronautics and Astronautics from Stanford University, Stanford, CA. After earning the B.S. degree he worked as a Structural Analyst with Boeing for several years before pursuing graduate studies. Since receiving his Ph.D. he has been an Engineering Research Associate in the Structures and Composites Laboratory at Stanford University. His current research is focused on micro and nano scale sensor and actuator networks, including MEMS and NEMS, built on polymeric expandable substrates for structural health monitoring and intelligent structures. His past research has addressed failure mechanisms, damage detection, and structural health monitoring in composite and advanced fiber metal laminate materials. 

  38. Monday, December 9

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

    Speaker:  Professor Sergei Krasheninnikov, University California - San Diego
    "Multifaceted Physics of Edge Plasmas"

  39. Monday, December 9

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Professor James D. Callen, University of Wisconsin-Madison
    "Pedestal Structure Without And With 3D Fields" 

  40. Friday, December 6

    12:05 PM

    Midwest Mechanics Seminar

    106 Engineering Research Building

    Speaker:  Professor Allan F. Bower, Brown University
    “Mechanics of Deformation, Diffusion and Failure in Lithium Ion Insertion Electrodes”
    Abstract:  The materials used in lithium ion insertion electrodes experience large changes in volume as the battery is charged or discharged and they absorb or emit lithium.  For example, a graphitic electrode increases in volume by 10% when lithiated; while high-capacity materials such as Si expand by up to 300%.   The stress generated by this volume expansion can lead to plastic flow and fracture, which cause batteries to lose their capacity.  There is consequently great interest in designing failure resistant composite battery microstructures.  Modeling deformation and failure in candidate battery materials, together with careful experimental measurements of the behavior of battery materials during lithiation will be important steps in this process. To this end, we formulate the continuum field equations and constitutive equations that govern deformation, stress, and electric current flow in a Li-ion half-cell.  The model considers mass transport through the system, deformation and stress in the anode and cathode, electrostatic fields, as well as the electrochemical reactions at the electrode/electrolyte interfaces.  The influence of phase transformations in the electrode material will also be discussed. Model predictions are compared with experimental measurements of stress and electric potential in thin-film electrodes that are repeatedly lithiated and de-lithiated.  Calculations reveal a complex interplay between stress and chemistry in electrode materials – stresses can directly influence the electrical response of the electrode; and conversely, chemistry can have a profound influence on the stress state within the electrode, in some cases even changing the signs of the stresses.
    Biography:  Allan Bower is Royce Family Professor of Teaching Excellence and Professor of Engineering at Brown University.  He received undergraduate and graduate degrees from the University of Cambridge.   He has served as co-director of the GM-Brown collaborative research laboratory in computational materials research for the past 8 years. His research interests have included contact mechanics, fracture mechanics, thin films, electromigration failures in interconnects, multiscale modeling of formability in high strength steels and lightweight Aluminum and Magnesium alloys, and mechanics of energy storage materials.

  41. Thursday, December 5

    12:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Dr. Kurt A. Terrani, Oak Ridge National Laboratory
    "Critical Examination of SiC Technology for LWRs"
    Abstract: SiC-based materials have been proposed at least as late as a decade ago for utilization in light water reactor platforms. Specifically, applications in fuel bundle structures are being pursued due to good neutronic characteristics and irradiation resistance for nuclear grade SiC materials. However, many basic gaps remain on the path to full deployment that require detailed and fundamental research. This discussion outlines these gaps and provides the results of latest research at ORNL aiming to understand and address these areas. Specifically, detailed discussions on high-temperature water vapor oxidation and thermo-mechanical analysis of the in-pile performance of these structures are provided.
    Biography: Kurt Terrani is currently a Weinberg Fellow R&D staff member at Oak Ridge National Laboratory in the Nuclear Fuel Materials and Fusion Materials and Nuclear Core Structures Groups. He received his Ph.D. in nuclear engineering from University of California, Berkeley. During his graduate studies he was advised by Prof. Donald Olander while working on hydride fuel concepts for LWR applications. His current research focuses on advanced nuclear fuel development for LWR platforms. The range of his research activities includes fuel fabrication, characterization, modeling, severe accident analysis and testing, and in pile experimentation. He currently leads three irradiation and PIE experiments at US and international test reactors.  

  42. Monday, December 2

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

    Speaker: Dr. Liang Lin, University of California - Los Angeles
    "Energetic-Particle-Driven Instabilities and Induced Fast-Ion Transport in a Reversed Field Pinch"

  43. Tuesday, November 26

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Dr. Matthew R. Brake, Sandia National Laboratories
    "Introduction to and Progress towards the ASME Research Committee on the Mechanics of Jointed Structures' Joint Challenges"

  44. Monday, November 25

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

    Speaker: Professor Jan Egedal, University of Wisconsin-Madison
    "Introducing TREX, a Terrestrial Reconnection Experiment"

  45. Thursday, November 21

    12:30 PM

    Special Plasma Seminar

    4274 Chamberlin Hall

    Speaker: Prabal Chattopadhyay, IPR, Gandhinagar, India
    "Wave Propagation and Potential Structures in an Expanding Helicon Plasma"
    Abstract: Diverging magnetic fields are found naturally in universe including our magnetosphere and in solar coronal funnels.  Diverging magnetic fields are used in expanding plasmas to accelerate particles by electric fields produced by localized potential structures, called double layer, formed self consistently inside the plasma. Acceleration of charged particles in low temperature plasmas is of interest to surface function modification as well as to development of electrostatic thrusters. This presentation will discuss the role of diverging magnetic fields in helicon source operation and self consistent potential structure formation in bulk of plasma.  A geometrically expanding (small diameter source attached to a bigger diameter expansion chamber) linear helicon device along with various diagnostics is designed and built with a diverging magnetic field. The helicon plasma produced with an m = +1 half helical antenna powered by a 2.5 kW RF power source at 13.56 MHz is characterized. Mode transitions are observed and mode structures are studied at low magnetic fields (<100 G). Though a monotonic increase in density with magnetic field is expected for helicon plasma, multiple density peaks are observed for the first time for field variations at low magnetic fields and are explained on the basis of oblique resonance of helicon waves in a bounded geometry for the first time. Characterization on both sides of the antenna at low magnetic fields revealed the role of left circularly polarized waves in electron cyclotron absorption in bounded plasmas. Changing the magnetic field topology at low magnetic fields, it is found that diverging magnetic fields near antenna can increase the efficiency of the source as high as 80 % from the zero field case. With a magnetic field ~ 100 G near the source and ~ 10 G at the end of the expansion chamber, density peaks on axis are observed nearly two wavelengths away from the antenna where the field is ~ 35 G. Helicon wave phase measurements show that the wave does not propagate in the source region owing to the density cut-off of the wave but starts to propagate in the downstream for lower densities and magnetic fields. Finally, diverging magnetic fields and their gradient near the geometrical expansion location are varied to create strong potential structures along the magnetic field direction. Observation of multiple potential structures in current free plasmas will also be presented.

  46. Monday, November 18

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

    Speaker: Professor Hyeon K. Park, Ulsan National Institute of Science and Technology, Ulsan, Korea
    "2D/3D visualization of MHDs and Turbulence study in KSTAR"

  47. Thursday, November 14

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

     Speaker: Dr. Daniel Segalman, Sandia National Laboratories
    "Modeling Joint Structures: They are Nonlinear and Difficult"
    Abstract: The dynamics of built up structures – things put together with nuts and bolts, rivets, or other compression-type fittings – are demonstrably nonlinear. In our quest to obtain predictive models for structures, we are driven to account for that nonlinearity in our models. This move toward reproducing observable physics in our models presents several serious challenges:  1. Devising models for joint mechanics that are consistent with laboratory experiments on both full structures and on individual joints.  2. Incorporating those joint models into structural models.   3. Formulating those models so that they are computationally tractable.    Much has been accomplished in each of these issues in the last decade, and much of that progress is due to the Joints Research Team at Sandia National Laboratories. Though still primitive, these technologies substantially advance the predictive capability of dynamics of real structures.  Of particular focus in this talk are the numerical difficulties that arise as greater fidelity joint models are employed and a novel method of model reduction that mitigates some of this difficulty.
    Biography:  Dan Segalman is a Distinguished Member of Technical Staff at Sandia National Laboratories, where he has been since 1986. In that time he has worked in a wide variety of topics including the geo-mechanics of salt domes for the Strategic Petroleum Reserve, laser welding, aging of rubber components, mechanics of polyelectrolyte gels, and nonlinear vibrations and vibration of rotating structures. Most recently he has been working on uncertainty quantification (UQ) and quantification of margin and uncertainty (QMU).  Prior to coming to Sandia, Dr. Segalman performed research in reservoir simulation and in geo-mechanics at Atlantic Richfield Production Research Laboratories. Prior to that he studied tire mechanics at General Motors Research Laboratory.  Dr. Segalman earned his PhD in Engineering Mechanics from the University of Wisconsin, Madison.

  48. Tuesday, November 12

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

     Speaker: Professor Michael Arnold, University of Wisconsin - Madison
    "Semiconducting Carbon Nanomaterials for Advanced Electronics and Light Harvesting"
    Abstract: In this talk, I will detail two of our recent advances in (1) realizing carbon nanotube-based light harvesting materials and (2) graphene and graphene nanostructure engineering and CVD. (1) We have discovered how to efficiently harvest photons using semiconducting carbon nanotubes. Usually, when a film of nanotubes is illuminated, the photogenerated electron/hole pairs (excitons) are “stuck” to each other and rapidly lost to heat. We have overcome this problem and unlocked nanotubes’ potential as absorbers by (i) dramatically reducing their structural and electronic heterogeneity and (ii) discovering how to drive the dissociation of excitons in the materials using type-II donor/acceptor heterojunctions. (2) My group has pioneered a synthetic method for rationally growing graphene nanostructures by chemical vapor deposition (CVD) with tailored shape, size, and crystallographic orientation. Our approach called barrier-guided CVD (BG-CVD) confines the lateral crystal growth of monolayered graphene to nm-scale channels and features. This strategy for bottom-up growth coupled with the use of sub-10 nm lithographic templates formed using self-assembled block copolymers give us a powerful pathway for realizing wafer-scale arrays of high-quality nanostructured graphene materials with tailored and novel properties, with relevance for semiconductor electronics, infra-red optoelectronics, and spintronics.
    Biography:  Michael S. Arnold joined the faculty of the Department of Materials Science and Engineering at the University of Wisconsin-Madison as an assistant professor in August 2008. There, he has built a research program in the fundamental materials science of carbon nanomaterials (nanotubes, graphene, and related nanostructures). Prof. Arnold graduated summa cum laude from the University of Illinois at Urbana-Champaign with a Bachelor of Science degree in Electrical Engineering in 2001. He earned his Doctor of Philosophy degree in 2006 from Northwestern University in Materials Science and Engineering, pioneering carbon nanotube sorting with Prof. Samuel I. Stupp and Prof. Mark C. Hersam.  Prof. Arnold also conducted post-doctoral research at the University of Michigan at Ann Arbor, with Prof. Stephen R. Forrest, where he studied organic materials for white lighting and photovoltaics. Arnold has been a recipient of the ACS Arthur K. Doolittle Award in Polymeric Materials Science and Engineering (2012); the Presidential Early Career Award for Scientists and Engineers (PECASE) – nominated by the U.S. Department of Defense, Army Research Office (2011); the U.S. Department of Energy (DOE) Early Career Research Award (2011); and a 3M Non-Tenured Faculty Award (2011, 2012, 2013).

  49. Monday, November 4

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

    Speaker:  Dr. Brett Chapman, University of Wisconsin - Madison
    "Unified Parametric Dependence, Control, and Reconstruction of 3D Equilibria in the RFP"
    Speaker: Dr. Mark Nornberg, University of Wisconsin - Madison
    "Direct Measurement of Turbulent Resistivity"
    Abstract: We have directly measured the vector turbulent emf in a two-vortex flow of liquid sodium in the Madison Dynamo Experiment. Using a novel probe design, we simultaneously measure magnetic and flow fluctuations to determine their correlated effect on mean-field induction. Through our electromagnetic model for the flow-induced mean magnetic field, constrained by measurements throughout the flow, we construct the vector mean current density at the probe location. With this information we are able to construct the mean-field model for the alpha and beta-effect terms of the turbulent emf and compare them with the direct measurement of the time averaged correlated fluctuations. The measured turbulent emf is anti-parallel with the mean current and is almost entirely described by an enhanced resistivity. The residual turbulent resistivity presents a difficulty for establishing the onset of the kinematic dynamo in a laboratory turbulent flow in that the effective magnetic Reynolds number is reduced making it more difficult to exceed the critical Rm. We have demonstrated that this enhanced resistivity can be mitigated by eliminating the largest-scale eddies. By tailoring the large-scale flow, we have achieved flows operating near threshold for dynamo self-excitation.

  50. Monday, November 4

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Topic: dry runs for posters that will be presented during the American Physical Society (APS) meeting.
    Note:  there will be no Plasma Theory Seminar on November 11 or November 18, 2013 due to the APS meeting.

  51. Monday, October 28

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

    Speaker: Dr. Geoffroy Lesur, Centre National de la Recherche Scientifique, Institute of Planetology and Astrophysics of Grenoble
    "Non-Ideal MHD Effects in Protoplanetary Discs"
    Abstract: The magnetorotational instability (MRI) is the most promising mechanism by which angular momentum could be efficiently transported outwards in astrophysical discs. However, its application to protoplanetary discs remains problematic. These discs are so weakly ionised that they may not support magnetorotational turbulence in regions referred to as `dead zones'. The plasma dynamics inside these dead zones is highly sensitive "non ideal" MHD effects such Ohmic resistivity, Hall effect and ambipolar diffusion. Despite being largely dominant in protoplanetary discs, Hall and ambipolar diffusions have been largely ignored in numerical studies of the MRI until recently.
    In this seminar, I will present several key results on how these effects are likely to modify the behaviour of the gas in protoplanetary discs. After presenting the main physical properties of astrophysical discs, I will revisit the MRI problem including Hall and ambipolar diffusion. I will then introduce the first local, three-dimensional, resistive Hall-MHD simulations of the MRI in situations where the Hall effect dominates over Ohmic dissipation. Confirming linear stability analysis, I will demonstrate that the Hall effect allows the MRI to exist in plasmas with very low ionisation fractions. However, instead of vigorous and sustained magnetorotational turbulence, I will show that the MRI saturates quiescently by producing large-scale, long-lived, axisymmetric structures in the magnetic and velocity fields. Implications for protoplanetary disc structure and evolution, as well as for theories of planet formation, will be briefly surmised.

  52. Monday, October 28

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Eric Howell, University of Wisconsin - Madison
    "Analysis of Nonlinear Poisson Equation in a Corner with Application to Grad-Shafranov Equilibria" 

  53. Tuesday, October 22

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Professor Melih Eriten, University of Wisconsin-Madison
    "Nonlinearities in Presliding Friction"
    Abstract: Presliding friction is the resistance to tendency to move in stationary contacts, which appears ubiquitously in nature and engineered systems, such as tectonic plate interactions leading to earthquakes; transmission of traction in rolling motion; mechanical joints in assembled structures; fretting wear of human joint implants; friction-based sound generation in spiny lobsters; thin film and coating-substrate interfaces; fiber-matrix interactions in composites; particle interactions in granular materials; and atomic-scale stick-slip oscillations. In all of these examples, presliding friction constitutes the major source of energy losses and nonlinearities. Due to these energy losses and nonlinearities, sophisticated models of assembled structures fail to predict dynamic responses observed in practice. This, in turn, necessitates use of large safety factor, and expensive surface texturing and coating techniques in design and manufacturing. Researchers have been studying presliding friction since the 1940s. However, load-dependent nonlinearities observed in static friction coefficients, compliance and energy dissipation still remain unresolved. When deformation-based forces are prevalent during presliding, static friction coefficients and compliance are decreasing functions of external loading. In contrast, energy dissipation increases with increasing tangential loading. This rather complicated physics can be understood thoroughly only through testing and modeling at high spatial and temporal resolutions, and involving multiple disciplines including chemistry, materials science, tribology, mechanics, dynamics, and structural engineering. In this talk, I present a multiscale approach to the presliding problem and preliminary results explaining the load-dependent nonlinearities. This multiscale framework promises to couple material and surface properties to contact geometries and external loading. Multiscale nature in spatial and temporal domains is first resolved at asperity-scales, and then, scaled up to practical rough surface-scales. This talk will also highlight the broader applicability of the proposed approach in dynamical systems containing a multitude of contact interfaces. In particular, uneven distribution of nonlinear compliance and damping among vibrational modes of assembled structures will be attributed to nonlinearities in interfacial mechanics and presliding friction.
    Biography: Professor Melih Eriten received his bachelor’s degree in mechatronics engineering with a minor in mathematics from Sabanci University, Istanbul, in 2005; and his master’s degree in applied mathematics and Ph.D. in mechanical engineering from the University of Illinois at Urbana-Champaign (UIUC) in 2005 and 2011, respectively. He worked as a postdoctoral research associate at UIUC’s Linear and Nonlinear Dynamics and Vibrations Laboratory and served as a visiting lecturer. In July 2012, Dr. Eriten joined the faculty at the University of Wisconsin-Madison as a tenure-track assistant professor in the department of mechanical engineering. His research interests are in contact mechanics and tribology, multiscale testing, characterization and modeling of materials, and nonlinear dynamics of materials and assembled structures. He is the author/co-author of 20 journal articles and 18 articles in conference proceedings, and has delivered a number of technical presentations and invited talks. In 2012, Dr. Eriten received ASME’s Marshall B. Peterson Award for significant contributions in pre-sliding behavior of frictional contacts.

  54. Monday, October 21

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Professor James D. Callen, University of Wisconsin-Madison
    "Coulomb Collision Effects on Linear Landau Damping"

  55. Monday, October 21

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

    Speaker: Professor William Dorland, University of Maryland
    "Is ITER DEMO-Relevant?" 

  56. Tuesday, October 15

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Professor Andrew J. Dick, Rice University
    "Impact Response Characterization for Aerospace Structures"
    Abstract: In certain military and industrial applications, systems and structures can be exposed to extreme impact loading conditions. These conditions can result in the impulsive loading of the structure with very high magnitude and very short duration forces. The high magnitude loading can result in significant nonlinear influence in the response and the short durations can result in an input with frequency content extending up beyond the kHz range. While methods exist to address each of these properties separately, the combination of the two conditions presents a unique and interesting problem. In this work, we have focused on the development of computational tools in two areas: force identification and nonlinear modeling. Force identification techniques have been developed in order to use local response data to determine time-series information as well as the location where the impact force was applied. Through the use of local response behavior, this method does not require a model of the complete structure but only the portion where the impacts are expected to occur. By using response data from numerical simulations and experiments, these techniques have been studied and validated. Identified force information agrees well with simulated and experimentally measured values. A new modeling method has been developed in order to correctly capture high frequency content while accurately representing the nonlinear properties, either from finite amplitude response behavior or from effectively nonlinear material properties. The high fidelity performance has been obtained through the use of spectral-domain methods employing Fourier and wavelet transforms. In this initial work, simple structures such as rods, beams, and plates have been studied. Issues identified for existing nonlinear modeling methods have been eliminated and experimental validation of these methods is ongoing.
    Biography: Dr. Dick has been an assistant professor at Rice University since 2007. He received a Ph.D. in mechanical engineering from the University of Maryland, College Park. He research is focused on dynamics and vibrations of mechanical systems and structures with a focus on nonlinear phenomena. He has studied nonlinear dynamics in applications including micro-resonators, atomic force microscopes, structural vibration attenuation, and impact mechanics. He has published over 45 peer-reviewed journal and conference papers. He has organized/co-organized 9 symposia on topics related to his research. He is a member of the ASME technical committees on Dynamics and Control of Systems (Applied Mechanics Division) and Structures and Micro/Nano-Systems (Design Engineering Division).
  57. Monday, October 14

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

    Speaker: Professor Alain Brizard, Saint Michael's College
    "Beyond Linear Gyrocenter Polarization in Gyrokinetic Theory" 

  58. Monday, October 14

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Professor Carl Sovinec, University of Wisconsin - Madison
    "Simulated Flux-Rope Evolution During Non-Inductive Startup in Pegasus"

  59. Monday, October 7

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

    Speaker: Dr. Mohamed Sawan, University of Wisconsin - Madison
    "Nuclear Analysis Supporting ITER Blanket Design"

  60. Monday, October 7

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

     Speaker: Daniel Carmody, University of Wisconsin - Madison
    "The Role of Curvature Drift in the Collisionless Microtearing Mode"

  61. Monday, September 30

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Carson Cook, University of Wisconsin - Madison
    "The Effects of a Magnetic Island on Alfvenic Activity in MST"
  62. Monday, September 30

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

     Speaker:  Dr. Ian Parrish, Canadian Institute for Theoretical Astrophysics
    "Extended Heating in the Solar Wind: The Role of MHD Turbulence and Resonance"
    Abstract: The solar wind is an incredibly well-diagnosed collisionless plasma that exhibits a rich set of plasma physics phenomenology. As such, we can learn valuable lessons about other collisionless or anisotropic plasmas, including accretion onto the galactic center black hole, the intracluster medium of galaxy clusters, and even fusion experiments on earth. In this talk, I will focus on the long-standing problem of understanding the extended heating of the solar wind in the context of energy exchange between particles and waves, a ubiquitous theme in plasma physics. On the analytical side, I will discuss several resonant interactions (cyclotron and transit time damping) and Fermi Type-B interactions and the use of quasilinear theory to describe them. On the numerical side, I will focus on the use of test particle MHD as a numerical tool for studying wave-particle interactions. In particular, I will describe the computational method and highlight some of the fun numerical challenges in its development while highlighting its strengths and weaknesses. Finally, I will connect the analytical and numerical pieces to describe some of our results thus far on the heating of the solar wind. I'll also discuss where these results can be augmented by other computational approaches, such as hybrid methods or gyrokinetics, as well as discuss other possible applications of the test particle MHD method including relativistic particles and accretion disk turbulence.

  63. Tuesday, September 24

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    1152 Mechanical Engineering Building

    Speaker: Dr. Mark Anderson, University of Wisconsin - Madison
    “Advancements in High Temperature Energy Transfer for Electrical Power and Industrial Process Applications”
    Abstract: Dr. Mark Anderson will give an overview of some of the experiments and research currently being conducted in the UW-Madison Thermal Hydraulics Laboratory and department of Engineering Physics. This work relates to increased temperature and increased efficiency power production and high temperature energy transfer for industrial processes. Pushing operating conditions to higher temperatures in order to take advantage of Carnot efficiency limits requires advancements and understanding of limits in materials, fluids and existing power conversion technology. The development of power conversion systems such as the supercritical Carbon Dioxide power cycle begin to have efficiency and economic benefits as the working fluid temperature from nuclear and concentrating solar approach 600C. These cycles may also have benefits with regard to CO2 sequestration and are being considered for future fossil energy conversion power plants. In the case of nuclear or concentrated solar energy production higher outlet temperatures requires the use of high temperature heat transfer fluids such as liquid salts or liquid metals. These fluids may also help unlock trapped hydrocarbon resources through more environmentally benign technologies than are currently being pursued. Developing industry confidence and knowledge of working with these fluids along with the significant challenge of finding and qualifying compatible materials is a key goal of the thermal hydraulics Laboratory.

  64. Monday, September 23

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  Professor Stanislav Boldyrev, University of Wisconsin - Madison
    "Astrophysical Turbulence at Subproton Scales" 

  65. Monday, September 23

    12:05 PM

    Plasma Physics Seminar

    1800 Engineering Hall

    Speaker: Professor Anne White, Massachusetts Institute of Technology
    "New Turbulence Diagnostics for C-Mod and Progress on Transport Model Validation" 

  66. Tuesday, September 17

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

     Speaker:  Dr. James Miller, United States Department of Energy National Nuclear Security Administration
    "NNSA Nonproliferation Research and Development"
    Abstract: The Office of Nonproliferation R&D within NNSA’s Office of Defense Nuclear Nonproliferation provides the technical base for national agencies involved in the nuclear security and nonproliferation communities. This discussion will provide an overview of Nonproliferation R&D efforts with a focus on proliferation detection, arms control and treaty verification, and nuclear detonation detection, along with the capabilities at the National Center for Nuclear Security. A number of current projects will be highlighted. Scheduled for 45 minutes with an additional 15 minutes for Q&A.
    Biography: Dr. Miller is currently a NNSA Graduate Fellow in the Office of Nonproliferation R&D at the DOE’s National Nuclear Security Administration in Washington DC. Dr. Miller completed his PhD from Texas A&M University in 2013, and previously spent seven years working for Los Alamos National Laboratory as a Research Associate, where he completed research projects: (a) identifying and analyzing terrorist activities in South America; (b) conducting experiments of advanced spectroscopic portal monitors; (c) using open-source data mining to investigate worldwide unaccounted industrial radioactive sources.

  67. Monday, September 16

    12:05 PM

    Plasma Physics Seminar

    1610 Engineering Hall

    Speaker: Professor Walter Gekelman, University of California, Los Angeles
    "Chaos in Magnetic Flux Ropes" 

  68. Monday, September 9

    12:05 PM

    Plasma Physics Seminar

    2305 Engineering Hall

    Speaker: Professor Hartmut Zohm, Max-Planck-Institute of Plasma Physics (IPP), Garching Germany, and Visiting Professor, University of Wisconsin-Madison
    "Control of MHD Instabilities on ASDEX Upgrade"

  69. Monday, September 9

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

     Speaker:  Mordechai Rorvig, University of Wisconsin-Madison
    "Nature and Mechanisms of Optimal Shaping for ITG Modes"

  70. Wednesday, August 7

    12:00 PM

    Engineering Physics Seminar

    106 Engineering Research Building

    Speaker: Dr. Richard Martineau, Idaho National Laboratory
    "Advanced Simulation of LWRs using MOOSE"
    Biography: Dr. Richard Martineau (INL) began employment at the INL in July of 1989. He is manager of the Fuels Modeling and Simulation Department within the INL Nuclear Fuels and Materials Division. The department is responsible for those aspects of developing advanced numerical methods, scientific numerical packages, high-performance computing frameworks, and multiphysics analysis tools for nuclear fuel performance modeling and simulation. Dr. Martineau has twenty-four years experience conducting computational fluid dynamics research and investigations. Expertise includes computational fluid dynamics, nonlinear coupling methods for multiphysics applications, compressible material dynamics (including stress wave phenomena and shock physics), fluid dynamics and heat transfer theory, and thermodynamics. Dr. Martineau is the primary developer of the PCICE method and is leading the effort to develop the MOOSE-based application called Bighorn, which is designed to simulate single- and multi-phase conjugate heat transfer domains. He is also the programmatic and technical lead on the development of RELAP-7, the next generation nuclear reactor systems analysis capability. Dr. Martineau obtained a Ph.D. in Mechanical Engineering from the University of Idaho.

  71. Thursday, June 27

    3:00 PM to 4:30 PM

    Special Plasma Seminar

    1227 Engineering Hall

     Speaker: Dr. Michael Kotschenreuther, University of Texas - Austin
    "X-divertors and Snowflake Divertors in Tokamaks, and do they Generalize to Stellarators?"

  72. Thursday, May 23

    1:15 PM

    Special Plasma Seminar

    4274 Chamberlin Hall

    Speaker: Dr. Linda Sugiyama, Massachusetts Institute of Technology
    "Fast MHD Sawtooth Crash"
    Abstract: The m=1, n=1 sawtooth oscillation in a toroidal plasma is important for fusion burning, yet remains poorly understood. In the linear 1/1 internal kink mode in MHD (Bussac, 1976), toroidal mode coupling links the unstable m=1 kink over q<1 to more stable harmonics with m>1 over q>1. Nonlinear sawtooth theories, however, almost all use the m=1 harmonic alone. The result, reduced MHD, is too slow to explain observed sawtooth crashes at low resistivity; instead, non-MHD effects are usually invoked. 3D simulations have been difficult to interpret, so the incompressible RMHD result has been accepted for 3D MHD as well. Large scale numerical simulations, however, show that compressible and finite aspect ratio effects in full MHD completely change the picture, leading to a fast crash much closer to experiments. The crash can be qualitatively described by a large aspect ratio expansion, but not by RMHD. Sweet-Parker-type reconnection does not occur.  Both sound wave and compressional Alfven wave terms contribute and the crash does not follow the Kadomtsev model. Similar effects occur in other cross-field MHD instabilities in a torus and in fast reconnection in a slab configuration, as in space physics.

  73. Monday, May 13

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Mordechai Rorvig, University of Wisconsin - Madison
    "Optimal design of 2-D and 3-D shaping for linear ITG stability"

  74. Monday, May 6

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker: Professor John Sarff, University of Wisconsin - Madison
    "MST and the Reversed Field Pinch"

  75. Tuesday, April 30

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Dr. Dominque Brossard, University of Wisconsin-Madison
    "Media, Nuclear Energy, and Risk Perceptions Pre-Post Fukushima."
    Abstract: A common assumption among technical stakeholders is that media coverage is largely responsible for negative public perceptions toward nuclear energy. I will challenge this assumption through the discussion of two recent studies. The first examines risk perceptions toward nuclear power pre- and post- Fukushima using a nationally representative survey sample of American adults. The analysis goes beyond a simple look at aggregate risk perceptions, instead focusing on how specific subpopulations responded to the disaster event. In order to capture the role of social media in public discourse, the second study provides a systematic and comprehensive analysis of posts about nuclear energy on the popular microblog Twitter between December 2010 and May 2012. Implications for effective communication about nuclear energy will be discussed.
    Biography:  Dr. Dominique Brossard (Ph.D., Cornell University) is a Professor in the Department of Life Sciences Communication at the University of Wisconsin-Madison. She is on the Steering Committee of the UW-Madison Robert and Jean Holtz Center for Science and Technology Studies, and a member of the UW Center for Global Studies. She is also the leader of the Societal Implications of Nanotechnology group in NSF--funded Nanoscale Science and Engineering Center (NSEC). Dr. Brossard's research program concentrates on the intersection between science, media, and policy. One of the Board members of the International Network of Public Communication of Science and Technology, Brossard in an internationally known expert in public opinion dynamics related to controversial scientific technological innovation, such as biotechnology, stem cell research, nanotechnology and nuclear energy.
    Event Note: 3:45pm refreshments will be served.

  76. Monday, April 29

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker: Professor Houyang Guo, Institute of Plasma Physics Chinese Academy of Sciences, Hefei, Anhui, P.R. China; and chief experimental strategist of Tri Alpha Energy Inc.
         He will give two presentations:
    "Progress toward Long Pulse Operation in EAST Superconducting Tokamak"
    "Overview of C-2 Compact Toroid Merging Experiments"

  77. Monday, April 29

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Eric Howell, University of Wisconsin - Madison
    "Mercier Stability in Spheromak Equilibria"

  78. Tuesday, April 23

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Joyce Connery, Director of Nuclear Energy Policy for The White House.
                     This event is a special topic, open forum colloquium.
    Biography: Joyce Connery is the Director of Nuclear Energy Policy within the Office of International Economics on the National Security Council. In that position, Ms. Connery works to develop policy among agencies and align and coordinate programs covering nuclear safety, security and nuclear trade.  Previously, Ms. Connery served as Senior Policy Advisor to the Deputy Secretary of Energy. Prior to that post, she was the Director for Threat Reduction and Nuclear Energy Cooperation in the office of the WMD Coordinator at the National Security Council.  She served under both the Bush and Obama Administrations and was responsible for nuclear Cooperative Threat Reduction programs, the the Nuclear Security Summit, the President’s four year effort to secure vulnerable nuclear materials, international nuclear energy policy and bilateral security and trade agreements.
    Before working at the NSC, Ms. Connery served as Senior Policy Advisor to the Assistant Secretary for Defense Nuclear Nonproliferation at the National Nuclear Security Administration.  She also worked in various other capacities within that organization, to include:  nuclear security, nuclear safety, nonproliferation and export control policies. She served in Kazakhstan for two years, first as the Department of Energy's nonproliferation representative for the Embassy and then as the on-site project manager for the shut-down of the BN-350 fast breeder reactor.
    Event Note:  3:45pm refreshments will be served.

  79. Monday, April 22

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker:  Dr. Jeremy Hanson, Columbia University
    "Understanding and Controlling Resistive Wall Mode Stability in DIII-D" 

  80. Friday, April 19

    12:05 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker:  Dr. Oliver Schmitz, Institute for Energy and Climate Research of the Research Center Jülich, Germany
    "Three-Dimensional Edge Transport and the Impact on Plasma Surface Interactions with Resonant Magnetic Perturbation Fields at Tokamaks"
    Abstract: Three-dimensional (3D) magnetic perturbation fields are applied to high temperature plasma experiments to optimize the transport in the plasma edge and the resulting plasma wall interaction. While 3D magnetic field topologies are inherent to stellarator devices, the application of small, external 3D magnetic perturbation fields is a new and promising approach in tokamaks to control cyclic edge instabilities causing impulsive heat and particle loads to the first wall. The external 3D field applied breaks the axisymmetry and the standard assumptions for plasma edge transport have to be reconsidered. Thus the resulting plasma surface interaction is governed by the 3D field structure. This talk will survey experimental results on the formation of such a 3D plasma boundary and the stationary plasma edge transport is studied with a Monte-Carlo fluid plasma and kinetic neutral transport model (EMC3-Eirene) in direct comparison to the experiment at TEXTOR and DIII-D. It is shown that a 3D plasma boundary is induced resulting in 3D plasma surface particle and heat fluxes. Experimental quantification of the resulting material erosion at the wall elements shows that the net-erosion characteristic in a 3D boundary is highly dependent on the actual location in the 3D topology.  The consequences of these experimental observations for RMP ELM control at ITER are addressed using EMC3-Eirene modeling.

  81. Tuesday, April 16

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Dr. Paul A. Demkowicz, Idaho National Laboratory
    "Development and Performance Testing of Coated Particle Fuel for the Very High Temperature Gas-Cooled Reactor"
    Abstract: Modern tristructural isotropic (TRISO) fuel is extremely robust and capable of excellent fission product retention at normal reactor operating conditions and during high temperature accident scenarios where fuel temperature can peak near 1600°C or beyond. Development and testing of TRISO fuel is being performed in the US as part of the Very High Temperature Gas-Cooled Reactor (VHTR) project. This includes fuel fabrication, irradiation, and post-irradiation examination to assess fuel performance. The results of the first irradiation test have been very promising, with zero particle failures in-pile and low release of fission products through the TRISO coatings. Postirradiation examination of the fuel is providing an unprecedented level of information on fuel behavior in-pile, including characterization of kernel and coating microstructures, migration of fission products in the coating layers, and examination of specific particle defects that can lead to elevated fission product release. This presentation will provide an overview of the VHTR fuels program and discuss some of the latest results from irradiation testing and post-irradiation examination.
    Biography: Dr. Paul Demkowicz is a Distinguished Staff Scientist at the Idaho National Laboratory. He holds a BS degree in Ceramic Engineering from the University of Washington and MS and PhD degrees in Materials Science and Engineering from the University of Florida. He has worked at the Idaho National Laboratory for the last 10 years, where his current focused is on the development and characterization of fuels for advanced nuclear reactors. Dr. Demkowicz is the technical lead for the post-irradiation examination and high temperature safety testing of coated particle fuel for the Very High Temperature Reactor project.
    Event Note: 3:45pm refreshments will be served

  82. Tuesday, April 9

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Dr. Andrew T. Nelson, Los Alamos National Laboratory
    "Development of Structure-Property Relationships for UO2 in Extreme Environments and Implications to Development of Next-Generation Commercial Nuclear Fuels"
    Abstract: Uranium dioxide (UO2) represents the single most relevant fuel to nuclear reactors around the globe. Researchers at the Fuels Research Laboratory (FRL) at Los Alamos are currently working to address these challenges through deployment of advanced techniques to study the fundamental properties of actinide ceramics. The focus of this talk will be devoted to ongoing work in two areas. First, the oxidation kinetics of UO2 during exposure to water vapor has been of renewed interest following the events at Fukushim. Second, oxidation has been long understood to degrade thermal transport properties of UO2. Ongoing efforts in the modeling and simulation community have been working on this problem, but experimental data obtained at temperatures exceeding 1000°C is sparse and contradictory. The talk will conclude with discussion of the future of oxide ceramic nuclear fuels with an eye toward potential evolutionary chemical and microstructural tailoring techniques that may improve fuel performance in the decadal timeframe for deployment in the existing fleet.
    Biography: Dr. Andrew T. Nelson is a research scientist in the Materials Science and Technology Division at Los Alamos National Laboratory. He received his B.S. in Engineering Mechanics followed by his M.S. and Ph.D. in Nuclear Engineering from the University of Wisconsin-Madison. His research interests are focused on the study of thermophysical properties of both metals and ceramics at high temperatures, with an emphasis on materials for nuclear applications and development of advanced experimental techniques. Currently, Nelson is the Ceramic Fuels Irradiation Testing Lead within the DOE-NE Fuel Cycle Research and Development program and leads the Fuels Research Laboratory at Los Alamos.
    Event Note:  3:45pm refreshments will be served

  83. Monday, April 8

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Sherwood Fusion Theory Conference poster previews

  84. Monday, April 8

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker:  Professor Alan Hoskinson, Tufts University
    "Design, Diagnostics, and Applications of High-Frequency Microplasmas" 

  85. Friday, April 5

    12:05 PM to 1:00 PM

    Midwest Mechanics Seminar

    106 Engineering Research Building

    Speaker: Professor K.T. Ramesh, Decker Professor of Science & Engineering, The Johns Hopkins University
    "Rocks, Shocks and Asteroids"
    Abstract: Recent events (such as the Chelyabinsk meteoroid and asteroid 2012 DA14) have demonstrated the need to understand major impact and fragmentation events. Many of the fundamental problems of current interest in national security also involve impact and fragmentation, typically studied through large-scale computational simulations. We attempt to address these issues through fundamental high-strain-rate experiments, high-speed visualization, and theoretical and computational modeling of failure processes, and simulations of asteroid damage and disruption. We use ultra-high-speed photography (exposure times as short as 20 nanoseconds) to observe the dynamic failure processes in brittle solids, and correlate the high-speed photographs with time-resolved measurements of the stresses in the specimen. Next, we use similar experiments to examine the strength and failure of meteorites. Based on these results and analytical models for dynamically interacting cracks, we construct a scaling model for the strength and failure of brittle solids under impact loading. We explore the implications of this model for armor ceramics, impact cratering (e.g. the simple to complex crater transition on Mars and Mercury), and the disruption of incoming asteroids.  

  86. Monday, April 1

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker:  Dr. Matthew Reinke, Oak Ridge Institute for Science and Education
    "Mitigating the Tokamak Heat Exhaust Problem Using Impurity Radiation: Successes and Limitations" 

  87. Monday, April 1

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Dr. Peter Lyons, Assistant Secretary for Nuclear Energy, U.S. Department of Energy
    "The Office of Nuclear Energy: Roles, Objectives, and Priorities"
    Abstract: Dr. Lyons will speak on the Office of Nuclear Energy’s role, objectives, and priorities. Key areas of focus this year include small modular reactors, the Department of Energy’s Strategy for the Management and Disposal of Used Nuclear Fuel and High-Level Radioactive Waste and research impacts from the Fukushima Dai-ichi accident in Japan.
    Biography:  Dr. Peter B. Lyons was confirmed by the Senate as the Assistant Secretary for Nuclear Energy on April 14, 2011. Dr. Lyons was appointed to his previous role as Principal Deputy Assistant Secretary of the Office of Nuclear Energy in September, 2009. As Assistant Secretary, Dr. Lyons is responsible for all programs and activities of the Office of Nuclear Energy. Previously, the Honorable Peter B. Lyons was sworn in as a Commissioner of the Nuclear Regulatory Commission on January 25, 2005 and served until his term ended on June 30, 2009.
    He received his doctorate in nuclear astrophysics from the California Institute of Technology in 1969 and earned his undergraduate degree in physics and mathematics from the University of Arizona in 1964. Dr. Lyons is a Fellow of the American Nuclear Society, a Fellow of the American Physical Society, was elected to 16 years on the Los Alamos School Board and spent six years on the University of New Mexico-Los Alamos Branch Advisory Board.
    Event Note:  3:45pm refreshments will be served 

  88. Wednesday, March 20

    3:30 PM

    Special Seminar

    1163 Mechanical Engineering Building

    Speaker:  Dr. Tsahi Gozani, Rapiscan Systems Inc.
    "Active Nuclear Based Inspection Technologies for the Detection of Nuclear Materials and Other Threats"
    Event Note: The American Nuclear Society is a co-sponsor of this seminar

  89. Tuesday, March 19

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

     Speaker:  Professor Gregory Moses, University of Wisconsin - Madison
    "Fourteen Years of Blended learning – Worth it or Not?"
    Abstract: Dramatic improvements in student learning outcomes resulting from blended learning implemented in a flipped WisCEL lab classroom will be reported. Specifically, the percentage of students scoring 95-100% on proctored exams increased from 3% in 2008 to 45% in 2012 with little change in course content. The reasons for this dramatic improvement over what was in 2008 considered a “best practice” blended course will be proposed. This outcome of the blended learning format raises the stakes for advocates in favor of blended learning in the debate with those who argue it is not worth the additional faculty effort.
    Biography: Professor Moses' research interests include numerical modeling and computational engineering. His work currently involves modeling dense plasmas for inertial confinement fusion applications. His interests in fusion include radiation hydrodynamics modeling of ICF plasmas, and atomic physics associated with the radiative properties of dense plasmas. He is involved in the ICF reactor design effort that many of the aforementioned areas support. He is also pursuing education research in the area of technology enhanced learning using the internet.
    Event Note: 3:45 PM refreshments will be served

  90. Monday, March 18

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

     Speaker:  Robert Wilcox, University of Wisconsin - Madison
    "Overview of Results and Ongoing Work at the Helically Symmetric Experiment (HSX)"

  91. Monday, March 11

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

     Speaker:  Professor Chris Hegna, University of Wisconsin - Madison
    "Quasisymmetric Stellarator Optimization Studies"

  92. Monday, March 4

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

     Speaker:  Dr. Aaron Bader, University of Wisconsin - Madison
    "Edge Modeling for Advanced Stellarators"

  93. Monday, March 4

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker: Dr. George McKee, University of Wisconsin - Madison
    "Turbulence in Magnetically Confined Plasmas"

  94. Tuesday, February 26

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Dr. Anthony Scopatz, University of Chicago
    "Not Your Physicists' Entropy: Information Theory Applications to the Nuclear Fuel Cycle"
    Abstract:  "This talk will demonstrate existing and nascent entropy-based measures which were used to quantify the sensitivities and covariances of nuclear fuel cycle (NFC) input parameters to system-wide output metrics. Here, thirty independent fuel cycle parameters for a Fast Reactor-Light Water Reactor hybrid scenario were varied simultaneously and stochastically. This talk will also cover the essential physics, quasi-static fuel cycle simulator Bright which was written to obtain physically meaningful results in such a large option space. Over 100,000 distinct Bright instantiations were computed to achieve adequate statistics. This represents orders of magnitude more information than garnered by one-dimensional base case perturbation studies."
    Biography:  "Dr. Anthony Scopatz is currently a post-doctoral scholar in high energy density physics at the Flash Center at the University of Chicago. He received his Ph.D. in Nuclear Engineering at the University of Texas at Austin, specializing in computational fuel cycle and reactor physics modeling. He is also the founding treasurer and board member of NumFOCUS, Inc., -- a 501(c)3 non-profit promoting open source computational science."
    Event Note:  3:45 PM refreshments will be served.

  95. Monday, February 25

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Dr. Ping Zhu, University of Wisconsin - Madison
    "Plasmoid Formation in Current Sheet with Finite Normal Magnetic Component"

  96. Monday, February 25

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker: Professor Amy Wendt, University of Wisconsin - Madison
    "Observing Plasma Complexity: Optical Diagnostics for Electron Energy Distributions"

  97. Tuesday, February 19

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Professor Matt Allen, University of Wisconsin - Madison
    "Validation and Methods of Dynamic Substructuring"
    Abstract:  "Dynamic substructuring provides an analyst the ability to perform tests on small, simple structures and combine them into a single built-up structure. This methodology often decreases the cost of analysis because expensive tests and simulations on large models can be avoided in favor of smaller, component-level tests. Dynamic substructuring has been successfully utilized in the analytical domain for several decades; however, experimental substructuring has lagged behind. Experimental substructuring often gives poor results due to sensitivity of the applied constraints to experimental errors, causing some analysts to be reluctant to use it. A new method for substructuring, dubbed the Transmission Simulator Method, has shown promise to reduce this sensitivity by softening the constraints. However, even with this new methodology, substructuring can give poor results. It would be helpful to be able to perform a validation experiment to give confidence in the results predicted by substructuring. This validation experiment is ideally inexpensive to perform and analyze as to not add significant cost to performing a substructuring analysis. This presentation gives an overview of substructuring methodologies and explores a new validation approach that can be used to assess the experimental errors which can cause substructuring to go awry. A Monte-Carlo simulation is performed in which random errors are applied to the system before substructuring is performed. The approach is then validated by simulating experimental-analytical substructuring of an engine-generator system."

  98. Monday, February 18

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Dr. Nobumitsu Yokoi, Institute of Industrial Science, University of Tokyo
    "Dynamic Balance in Turbulent Magnetic Reconnection: A Self-Consistent Turbulence Model"
    Abstract: Through the enhancement of transport, turbulence may contribute to the fast reconnection. However the effects of turbulence are not so straightforward. In addition to the enhancement of transport, turbulence under some environment shows effects that suppress the turbulent transport. In the presence of turbulent cross helicity, such dynamic balance between the transport enhancement and suppression occurs. As this result of dynamic balance, the region of effective enhanced magnetic diffusivity is confined to a tiny region, leading to the fast reconnection. In order to confirm this idea, a self-consistent turbulence model for the magnetic reconnection is proposed. With the aid of numerical simulations where turbulence effects are incorporated in a consistent manner through the turbulence model, the dynamic balance in the turbulence magnetic reconnection is confirmed.

  99. Monday, February 18

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker:  Dr. John Santarius, University of Wisconsin - Madison
    "Overview of UW Fusion Technology Institute Inertial-Electrostatic Confinement and Other Research"

  100. Monday, February 11

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  Dr. M. J. Pueschel, University of Wisconsin - Madison
    "Fast Magnetic Reconnection in the Presence of Drift Waves"

  101. Monday, February 11

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker:  Professor Paolo Ricci, Ecole Polytechnique Fédérale de Lausanne (EPFL)
    "Progressive Steps Towards Global Validated Simulation of Edge Plasma Turbulence"
    Abstract:  The Global Braginskii Solver (GBS) code has been developed to simulate plasma turbulence in edge-relevant conditions. We have initially studied relatively simple configurations of increasing complexity, linear magnetic configurations and simple magnetized toroidal devices. GBS has now reached the capabilities of performing nonlinear self-consistent global three-dimensional simulations of the plasma dynamics in the Scrape-Off Layer (SOL). By solving the drift-reduced Braginskii equations, the code evolves self-consistently the plasma flux from the core, turbulent transport, and the plasma losses to the limiter plates. This gradual approach has allowed gaining a deep understanding of turbulence, from identifying the driving instabilities to estimating the turbulence saturation amplitude. A code validation development project has been conducted side by side with the GBS development and the methodology to carry out experiment-simulation comparison has been applied to quantify the level of agreement between the GBS results and the TORPEX experiment.  This work is supported by the Swiss National Science Foundation.

  102. Monday, February 4

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  David Sondak, Rensselaer Polytechnic Institute
    "New Large Eddy Simulation Turbulence Models for Magnetohydrodyanmics"

  103. Monday, February 4

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker:  Professor Cary Forest, University of Wisconsin - Madison
    "Introduction to the Madison Plasma Dynamo Experiment"

  104. Tuesday, January 29

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Dr. John H. Jackson, Idaho National Laboratory
    "Advanced Test Reactor, National Scientific User Facility and Industry Interactions"

  105. Monday, January 28

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Jupiter Bagaipo, University of Maryland
    "Boundary Induced Amplification and Nonlinear Instability of Interchange Modes"

  106. Monday, January 28

    12:05 PM

    Plasma Physics Seminar

    1153 Mechanical Engineering Building

    Speaker: Dr. Michael Bongard, University of Wisconsin - Madison
    "Stability and Startup Studies at Near-Unity Aspect Ratio"

  107. Tuesday, December 18

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Professor Annalisa Manera, University of Michigan
    "Multi-Scale and Multi-Physics CFD-Based Computational Tools for Nuclear Applications and the need for CFD-Grade Experiments"
    Abstract: The application of Computational Fluid Dynamics (CFD) in the development of multiscale and multiphysics coupled tools will be discussed. The presentation will focus on the results obtained on the coupling between the US NRC 1D best estimate-thermal hydraulic code TRACE and the CFD code ANSYS-CFX, with special emphasis on the challenges encountered with 1D/3D interfaces and appropriate code validation. Additionally, considerations will be presented for the development of a multiphysics coupling involving CFD, a neutron transport code and a chemistry code for the high fidelity simulation of crud deposition on PWR fuel rods. Finally, the talk will address the design and performance of CFD-grade experiments aimed at the validation of advanced computational methodologies in thermal-hydraulics.
    Event Note: 3:45pm refreshments will be served. 

  108. Tuesday, December 11

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Professor Sara Pozzi, University of Michigan
    "Detection of Correlated Particles from Fission for Nuclear Safeguards and Nonproliferation"

  109. Monday, December 10

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Professor Jean-Luc Thiffeault, University of Wisconsin - Madison
    "Stochastic Field Lines and Braids" 

  110. Monday, December 10

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker:  Professor David Maurer, Auburn University
    "The Application and Use of 3D Stellarator Fields on the Compact Toroidal Hybrid to Avoid Tokamak Disruptions"

  111. Monday, December 3

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

     Speaker: Dr. M. J. Pueschel, University of Wisconsin - Madison
    "The Non-Zonal Transition in ITG Turbulence"

  112. Monday, December 3

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker:   Dr. Jason TenBarge, University of Iowa
    "Gyrokinetic Simulations of Solar Wind Turbulence and Dissipation"
    Abstract: Turbulence plays an important role in space and astrophysical plasmas by mediating the transfer of energy from large-scale motions to the small scales at which the turbulence can be dissipated. Recent advances in solar wind data extending to sub-electron scales have increased the focus on turbulence and dissipation at kinetic scales. Due to the nature of plasma turbulence, gyrokinetics is well suited to study weakly collisional kinetic plasmas, such as the solar wind. We present nonlinear gyrokinetic simulation results including: (1) energy spectra spanning the entire dissipation range from ion to sub-electron scales that show striking agreement with in situ solar wind data, (2) identification of a dissipation range anisotropic cascade of energy in agreement with predictions of critical balance, and (3) constraints on the physical origin of energy dissipation at kinetic scales.

  113. Monday, November 26

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker:   Professor Fred Skiff, University of Iowa
    "Observing the Acceleration of Suprathermal Electrons by Alfven Waves using the Diagnostic of Whistler-Mode Wave Absorption"
    Abstract:  Shear Alfven waves are believed to accelerate plasma electrons through both linear and nonlinear wave-particle interactions. In the LAPD plasma device wave packets of nearly-periodic plane waves with dB/B~10E-5 are generated using an arbitrary spatial waveform antenna in the central region of the plasma. When the perpendicular wavelength is shortened to a few times the collisionless skin depth a parallel electric field is produced that should be able to accelerate plasma electrons. The difficulty in observing these electrons is that the change to the distribution function is small and should be greatest at high velocity where the total number of particles is small. Preliminary results of using whistler-mode wave absorption as a diagnostic of the suprathermal electrons indicate that it is indeed possible to observe the effects produced by electron acceleration. We will discuss the problems of separating out the effect of changes in the bulk plasma density (including ducting) from the effects of wave damping (of the whistler-mode wave) that enable us to measure the perturbed electron velocity distribution to high resolution.

  114. Monday, November 26

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

     Speaker: Professor Paul Terry, University of Wisconsin - Madison
    "The Effect of Magnetic Flutter on Residual Flows"

  115. Tuesday, November 20

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Professor Carl Sovinec, University of Wisconsin-Madison.
    "Some Mechanics of Magnetohydrodynamics and How It Affects Plasma Simulation"
    Abstract:  Operation of the ITER magnetic confinement experiment will require control of macroscopic stability to avoid or to mitigate disruptions of the plasma discharge and other transient bursts of energy that can damage the device. Large-scale simulation is contributing to our understanding of the underlying dynamics, but improvements are needed for modeling realistic parameters over the time-scales of interest. Basic properties of ideal magnetohydrodynamics influence our ability to simulate non-ideal evolution. Analogies with continuum mechanics for linearly elastic media help illustrate important effects and why they are demanding for numerical representations. Results from numerical harmonic analysis with standard and modified representations demonstrate a promising new approach that can be ported to non-ideal plasma simulation.
    Biography:  Professor Sovinec is currently a professor with the Engineering Physics department at the University of Wisconsin – Madison. He received his BS in Physics from the United States Air Force Academy, MS in Nuclear Engineering from the University of Washington, and PhD in Physics from Wisconsin. His research interests lie in the numerical simulation of plasmas and fluids. His recent efforts have focused on simulating nonlinear electromagnetic behavior in magnetically confined plasmas, where the extreme stiffness and anisotropy resulting from the magnetic field provide great challenges for numerical approaches.
    Event Note: 3:45pm refreshments will be served.

  116. Monday, November 19

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:   Kirit Makwana, University of Wisconsin - Madison
    "Gyrokinetic Analysis of Subdominant Modes in Zonal Flow Regulated Turbulence"

  117. Monday, November 19

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker:  Dr. Jay Anderson, University of Wisconsin - Madison
    "Fast Ion Confinement and Stability of an NBI-heated RFP"
    Abstract:  The envisioned burning plasma experiment, regardless of magnetic concept, relies on sufficient confinement of the charged fusion products for plasma self heating. As such, the confinement of fast ions and their impact on the bulk plasma are crucial issues. While well-studied in tokamak, ST and stellarator plasmas, relatively little is known in RFP plasmas about the dynamics of fast ions and the effects they cause as a large population. These studies are now underway in MST with an intense 25 keV, 1 MW hydrogen neutral beam injector (300 MW/m^2 at injection port). Fast particles are confined much better than thermal particles in the stochastic RFP magnetic field, and a significant population of fast ions develops during NB injection. TRANSP simulations predict a super-Alfvenic ion density of up to 25% of the electron density with both a significant velocity space gradient and a sharp radial density gradient. There are several effects on the background plasma including enhanced toroidal rotation, electron heating and an altered current density profile. The abundant fast particles affect the plasma stability. Fast ions at the island of the core-most resonant tearing mode have a stabilizing effect, and up to 60% reduction in the magnetic fluctuation amplitude is observed during NBI. Simultaneously, beam driven instabilities are observed for the first time in the RFP. Repetitive 50 us bursts of m=1 modes have scaling signatures of both Alfvenic and continuum energetic particle modes. The dominant modes are n=4 (EP-like) and n=5 (AE-like), which nonlinearly couple to an n=1 mode. The feedback of the altered plasma stability on the fast ion confinement is investigated

  118. Tuesday, November 13

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:   Dr. John C. Brigham, University of Pittsburgh
    "From Concrete to the Cardiovascular System: Computational Mechanics for Engineering Inverse Problems"
    Abstract:  Advancements in computational mechanics and computing technologies have led to dramatic improvements in the ability to simultaneously simulate several physical processes through multiple spatial and temporal scales. Furthermore, opportunities for leveraging these forward modeling advancements are highly prevalent for the optimization, control, and/or characterization of increasingly complex systems through the development and utilization of sophisticated computational inverse solution strategies. This talk will present strategies to utilize computational mechanics for the solution of problems in characterization of material properties in manmade structures as well as diagnosis of variations in organ function related to disease. In particular, examples will be provided to show how the same tools used to efficiently characterize structural material properties from nondestructive testing can be applied to identify patterns in the kinematic function of the human heart that could potentially provide metrics for improved disease diagnosis and prognosis.
    Biography:  Dr. John Brigham received a BE in civil and environmental engineering and mathematics from Vanderbilt University in 2003, and a MS and PhD in civil and environmental engineering from Cornell University in 2006 and 2008, respectively. In the fall of 2008 Dr. Brigham joined the University of Pittsburgh as an assistant professor in the Department of Civil and Environmental Engineering and the Department of Bioengineering. His research interests are centered around advancing the fields of computational mechanics and inverse problems, to create novel techniques for the characterization, control, and optimization of physical processes.

  119. Monday, November 12

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker:  Professor James Callen, University of Wisconsin - Madison
    "RMP-Flutter-Induced Plasma Transport in DIII-D"

  120. Monday, November 12

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  Carson Cook, University of Wisconsin - Madison
    "The Shear Alfven Spectrum in the Presence of a Magnetic Island"

  121. Friday, November 9

    12:00 PM

    Plasma Physics Seminar

    4274 Chamberlin Hall

    Speaker:  Professor James Drake, Royal Institute of Technology, Stockholm
    "Overview of System Identification applications to MHD control"
    (how to control MHD activity without using the MHD equations in the feedback model)
    Abstract:  To date the approach to MHD control has largely been dependent on incorporation of the well known MHD models to provide the predictive capability required for synthesis of real-time, closed-loop active control algorithms. Through the use of system identification techniques Erik Olofsson has shown that it is possible to model magnetohydrodynamic stability based on unprejudiced empirical data derived from experimental observation (i.e. no MHD equations in the derived magnetohydrodynamic stability model). The ambition has been to approach experimental modal analysis in a generic manner without invoking prior MHD model knowledge. As stated in the thesis, using EXTRAP T2R data it has been possible to iteratively develop and reality-check both dynamical systems estimation/identification and control synthesis techniques.

  122. Friday, November 2

    12:00 PM

    Midwest Mechanics Seminar

    106 Engineering Research Building

    Speaker:  Professor Tim Colonius, California Institute of Technology
    "Bubble Dynamics with Biomedical Applications"
    Abstract:  Shock and ultrasonic waves in water often induce the growth and collapse of cavitation bubbles, or clusters of bubbles, which, in turn, can lead to erosion and other types of damage to nearby materials and structures.  In traditional applications like marine propellors, cavitation erosion is unambiguously undesirable, but in medical procedures such as lithotripsy and histotripsy, cavitation can amplify shock energy and thereby mediate stone erosion and tissue ablation, respectively, but it can also lead to collateral damage and other bioeffects.  We pose a series of model problems aimed at understanding the mechanisms at play during shock-induced collapse of cavitation bubbles near surfaces.  Numerical simulations of one or a few bubbles allow us to quantify the stresses induced in nearby surfaces and understand the role played by secondary shocks emitted during bubble collapse.  Under repeated shocks or continuous irradiation, clusters or clouds containing many bubbles are formed, and the complex, collective behavior of the cloud can lead to even greater focussing of energy or, at sufficiently high void fractions, to undesirable scattering and dispersion of energy.  Continuum bubbly flow models have been employed to qualitatively describe these effects, but quantitative predictions, especially at relatively high void fractions, require both better models and less computationally intensive ways to represent a poly-disperse cloud of bubbles.  We close by describing recent a recent effort aimed at achieving these goals.

  123. Tuesday, October 23

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Dr. Barry D. Ganapol,  University of Arizona
    "The Analytical Solution to the 1D Multigroup Diffusion Equation in Heterogenous Media"
    Abstract:  The analytical solution to the time-independent multigroup diffusion equation in heterogeneous plane, cylindrical and spherical media will be presented. The solution features the simplicity of the one-group formulation while addressing the complication of multigroup diffusion in a fully heterogeneous medium. Beginning with the vector form of the diffusion equation, the approach, based on straightforward mathematics, resolves a set of coupled second order ODEs. The analytical form is facilitated through matrix diagonalization of the neutron interaction matrix rendering the multigroup equation as a series of one-group equations. Customized eigenmode solutions of the one-group diffusion operator then represent the homogeneous solution in a homogeneous region. Once the homogeneous solution is known, the particular solution naturally emerges through variation of parameters. The analytical expression is numerically implemented through recurrence. We end with applications to the 1D/C5G7 MOX benchmark and an Advanced Test Reactor (ATR) fuel plate.
    Biography:  Dr. Ganapol currently works at the Department of Aerospace and Mechanical Engineering at the University of Arizona in Tuscon, AZ. He earned his Ph.D. in 1971 from the University of California, Berkeley. Barry Ganapol's research interests include radiation and particle transport theory, fast reactor safety, applied mathematics, and satellite remote sensing.
    Event Note:  3:45pm refreshments will be served.

  124. Monday, October 22

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  Mark Schlutt, University of Wisconsin - Madison
    "Self-Consistent Simulations of Nonlinear MHD and Profile Evolution in Stellarator Configurations"

  125. Monday, October 22

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker:  Michael Jaworski, Princeton Plasma Physics Laboratory
    "Local and global plasma response and plasma-facing component performance of the liquid lithium divertor in NSTX"

  126. Tuesday, October 16

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Dr. Anton Moisseytsev, Argonne National Laboratory
    "Modeling of the Supercritical Carbon Dioxide Brayton Cycle or Why Nuclear Engineers Need Classes in Turbomachinery, Art, and Everything in Between"
    Abstract:  Supercritical carbon dioxide (S-CO2) Brayton cycles offer potential advantages over other power converter systems in terms of the higher cycle efficiency and remarkably small turbomachinery. The cycle benefits originate from the CO2 properties behavior near the critical point. To accurately simulate the cycle performance and transient behavior, one needs to pay close attention to the effect of the properties variation on the performance of the turbomachinery, heat exchangers, control mechanisms , and other components. Many, if not all, existing "commercial" codes either ignore some of these effects or simply fail to converge in the proximity of the critical point. The presentation discusses the development of the Plant Dynamics Code at Argonne National Laboratory for the design and transient analysis of the S-CO2 cycle for nuclear power reactor applications and describes various engineering disciplines involved in modeling the cycle.
    Biography:  Dr. Anton Moisseytsev is a Principal Computational Nuclear Engineer at Nuclear Engineering Division of Argonne National Laboratory. He has eight years of experience in modeling and simulation of various reactor systems, including design and analysis of the advanced reactors and energy conversion systems, safety analysis of nuclear reactors, and code development for steady-state and transient simulations of nuclear power plants. Anton has been involved in the development of the supercritical carbon dioxide Brayton cycle at Argonne since 2002.
    Event Note:  3:45 PM refreshments will be served.

  127. Monday, October 15

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  Dr. S. Satake, National Institute for Fusion Studies, Toki, Japan
    "Development of Simulation Code for Neoclassical Viscosity Calculation and its Application"

  128. Monday, October 15

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker:  Professor Dmitri Uzedensky, University of Colorado
    "Strong Beaming of High-Energy Particle Acceleration and Radiation in Magnetic Reconnection in Relativistic Pair Plasmas"

  129. Monday, October 1

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker:  Dr. Laila El-Guebaly, University of Wisconsin - Madison
    "Neutronics of ARIES and ITER: Progress and Challenges"

  130. Monday, October 1

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  Daniel Carmody, University of Wisconsin - Madison
    "A Look at the Mechanisms of the RFP Microtearing Mode"

  131. Friday, September 28

    12:05 PM to 1:00 PM

    Midwest Mechanics Seminar

    106 Engineering Research Building

    Speaker:  Professor Sanjay Govindjee, University of California, Berkeley
    "Application of Statistical Mechanics in Thermo-Mechanics and Its Effects on Free-Energy Structure"

  132. Tuesday, September 25

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Professor Benoit Forget, MIT
    "OpenMC: An Open Source Monte Carlo Code for High Performance Computing"
    Abstract: A new Monte Carlo code called OpenMC is currently under development at the Massachusetts Institute of Technology as a tool for simulation on high performance computing platforms. Given that many legacy codes do not scale well on existing and future parallel computer architectures, OpenMC has been developed from scratch with a focus on high performance scalable algorithms as well as modern software design practices. The present work describes the methods used in the OpenMC code and demonstrates the performance and accuracy of the code on a variety of problems with a particular emphasis on two key innovations: 1) massively parallel fission bank algorithm, and 2) decomposition of tallies for efficient memory management.
    Biography: Professor Benoit Forget is currently an Assistant Professor at the Massachusetts Institute of Technology. He graduated from École Polytechnique de Montréal with a B.Eng in Chemical Enginering and a M.Eng in Energy Engineering in 2003. He then completed a PhD in Nuclear Engineering at the Georgia Institute of Technology in 2006. He spent a year at the Idaho National Laboratory working in the nuclear fuel cycle and reactor physic methods groups, before joining MIT in January of 2008. He recently served as the Chair of the Reactor Physics Division of the American Nuclear Society.
    Event Note: 3:45 PM refreshments will be served

  133. Monday, September 24

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  Dr. Vladimir Mirnov, University of Wisconsin - Madison
    "Ion-Acoustic Waves in Galaxy Clusters"

  134. Monday, September 24

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker:  Dr. Ivan Khalzov, University of Wisconsin - Madison
    "Dynamos in Spherical Boundary-Driven Flows"

  135. Monday, September 17

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker: Dr. Jaeho Kim, National Institute of Advanced Industrial Science and Technology (AIST), Japan
    "Innovative Plasma CVD Technology for the Synthesis of Carbon Nanomaterials (Nano Crystalline Diamond Film and Grapheme Film)"

  136. Monday, September 17

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Mordechai Rorvig, University of Wisconsin - Madison
    "Proxy Functions for Turbulent Transport Optimization of Stellarators"

  137. Monday, September 10

    12:05 PM

    Plasma Physics Seminar

    1310 Sterling Hall

    Speaker:  Austin Roach, Princeton Plasma Physics Laboratory
    "Instabilities of a Magnetized Free Shear Layer in Rotating Liquid Metal"

  138. Monday, September 10

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:   John O'Bryan,  University of Wisconsin - Madison
    "Simulation of Current-Filament Dynamics and Relaxation in the Pegasus ST"

  139. Friday, June 22

    1:00 PM to 2:00 PM

    Special Seminar

    106 Engineering Research Building

    Speaker:  Professor Tuomisto Filip, Department of Applied Physics, Aalto University, Finland
    "Irradiation Damage in Metals and Semiconductors Studied with Positrons"
    Abstract:  Positron annihilation spectroscopy is an experimental method that is particularly suitable for the identification and quantification of vacancy defects in metals and semiconductors. In a crystalline solid, positrons can get trapped at a vacancy defect thanks to the missing positive ion core that strongly repels positrons. In addition, in semiconductors the vacancy charge state plays a role, and negatively charged non-open volume defects can also be detected. The trapping of positrons at these defects is observed as well-defined changes in the positron-electron annihilation radiation. The combination of positron lifetime and Doppler broadening techniques with state-of-the art theoretical calculations provides the means to deduce both the identities (including vacancy decoration by impurities) and the concentrations of the vacancies.
    I will first give an introduction to the positron methods with illustrating examples from recent research. In the second part of my presentation I will review our latest results obtained in irradiated and/or ion implanted solids, ranging from elemental metals and model metal alloys to steels and novel semiconductor compounds. Finally, I will present some of the most recent developments in both theoretical and experimental positron methodologies.
    Biography:  Professor Filip Tuomisto obtained his PhD in engineering physics from the Helsinki University of Technology, Finland, in 2005. He specializes in the development of experimental methods based on positron annihilation spectroscopy and in the application of these methods to studying defects in crystalline solids. At present he holds an Associate Professor position at the Department of Applied Physics of Aalto University, Finland, where he leads the positron physics research group of  ~10 people (post-docs, PhD students). He has published more than 120 refereed scientific journal articles that have together been cited more than 1000 times.

  140. Monday, June 18

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  Aaron Bader, University of Wisconsin - Madison
    "Scrape Off Layer Modeling on Stellarators using EMC3-EIRENE"

  141. Monday, May 21

    4:00 PM to 5:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:   Professor James D. Callen, University of Wisconsin - Madison
    "RMP-Flutter-Induced Pedestal Plasma Transport"

  142. Tuesday, May 8

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Dr. Gary Bell, ORNL
    "Overview of Nuclear Fuel Development at ORNL"
    Speaker:  Dr. Kurt Terrani, ORNL
    "Fully Ceramic Microencapsulated Fuels for LWRs"
    Abstract:  High temperature nuclear reactors specifically designed for high efficiency electricity generation and high temperature heat applications will likely employ tri-structural isotropic (TRISO) coated particle fuel comprising a spherical metal oxide or oxycarbide ceramic fuel core or kernel surrounded by pyrocarbon and SiC coatings to retain fission products. This fuel form is extremely versatile; for a given fast or thermal reactor mission the TRISO coating design remains essentially the same while the kernel’s composition is varied: U for energy production, U/Th for resource sustainability, and U/Pu/minor actinides for used fuel management. Coated particle fuel is one of the few fuel forms that can be employed to achieve burnups and temperatures significantly beyond current experience. Dr. Bell will provide an overview of nuclear fuel development activities at ORNL and Dr. Terrani will be provide a more detailed discussion of recent results from work on Fully Ceramic Microencapsulated Fuels for LWRs.
    Biographies:
    Dr. Gary Bell joined ORNL in 1992 and is currently serving as the Group Leader for the Nuclear Fuel Materials Group in the Fuel Cycle and Isotopes Division. In his role as the Nuclear Fuel Materials Group Leader, he provides leadership for a variety of nuclear fuel cycle technical and infrastructure projects focused on nuclear fuel and target development.
    Dr. Kurt Terrani is currently a Weinberg Fellow - R&D staff member at Oak Ridge National Laboratory. He joined Nuclear Fuel Materials Group in Fuel Cycle Isotopes Division after receiving his Ph.D. in nuclear engineering from University of California, Berkeley. His current research focuses on advanced nuclear fuel development, characterization, modeling, and irradiation testing.
    Event Note:  3:45 PM refreshments will be served

  143. Monday, May 7

    12:05 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speaker:    Professor Jan Egedal,  Massachusetts Institute of Technology
    "Magnetic Reconnection in Plasmas; a Celestial Phenomenon in the Laboratory"
    Abstract:  Coronal mass ejections from the sun are the most explosive events that occur in our solar system. Closer to home, the aurora borealis is one of the most spectacular, naturally occurring, light show at high latitudes on the Earth. Both of these large scale events are driven by magnetic reconnection in plasmas. The spontaneous rearrangement of magnetic field topology provides the enormous energy needed for these celestially magnificent and diverse phenomena.
    For more than fifty years, magnetic reconnection has been a fascinating topic of research in plasma physics. While we do not fully understand the process of reconnection, significant progress has been made in the past decade through detailed analysis of laboratory experiments, and computer simulations. The Versatile Toroidal Facility at MIT is one such experiment dedicated to the study of magnetic reconnection. In this talk I will describe the recent experimental observations which have led to a new theoretical paradigm for magnetic reconnection. Large scale computer simulations support the theoretical and experimental results. The analysis of experimental observations in a laboratory device has led to a comprehensive understanding of data from spacecraft observing celestial reconnection events in the Earth’s magnetosphere.

  144. Monday, April 30

    12:05 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speaker and topic to be announced

  145. Tuesday, April 24

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Dr. Kent E. Wardle,  Argonne National Laboratory
    "CFD Simulation of Multiphase Flows in Aqueous-Based Nuclear Fuel Recycling"
    Abstract:  While the processes for liquid-liquid extraction based recycling of used nuclear fuel are well developed and a variety of technical options exist, advances need to be made in simplification, optimization, and improvement of overall efficiency. A hybrid multiphase method based on the combination of an Eulerian multi-fluid solution framework (per-phase momentum equations) coupled with sharp interface capturing using Volume of Fluid (VOF) on selected phase pairs has recently been developed using the open-source CFD toolkit OpenFOAM. In this context, the status of multiphase simulations for annular centrifugal contactors will be discussed along with an overview of concurrent experimental efforts aimed at validation of these advanced models for application to such contactors.
    Biography:  Dr. Kent Wardle, a recent graduate of the Engineering Physics Department, has been a staff member in the Process Simulation and Equipment Design Group in Argonne National Laboratory's Chemical Sciences and Engineering Division for the past 4 years. His research there has grown out of his doctoral work at UW which involved an in-depth computational and experimental analysis of a nuclear fuel cycle relevant piece of processing equipment—the annular centrifugal contactor. Kent’s current work focuses on large-scale, parallel computational fluid dynamics (CFD) simulations of multiphase, turbulent flows found in liquid–liquid contacting devices.
    Event Note:  3:45 PM, refreshments will be served

  146. Monday, April 23

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:   Kirit Makwana, University of Wisconsin - Madison
    "Role of Stable Modes in Zonal Flow Regulated Plasma Turbulence"

  147. Monday, April 23

    12:05 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speaker:   Dr. David Smith,  University of Wisconsin - Madison
     "Parametric Dependencies of Low-k Pedestal Turbulence in NSTX H-mode Plasmas"

  148. Monday, April 16

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  Mordechai Rorvig, University of Wisconsin - Madison
    "The Effects of 3-D Shaping on ITG Stability"

  149. Monday, April 16

    12:05 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speaker: Professor Gregory G. Howes, University of Iowa
    "Kinetic Turbulence in Space and Astrophysical Plasmas: Theoretical, Numerical, and Experimental Investigations"
    Abstract:  In many turbulent space and astrophysical plasma environments, the dissipation of the turbulence, and consequent conversion of turbulent fluctuation energy to plasma heat, occurs at scales on which the plasma dynamics is collisionless. Direct access to the near Earth solar wind provides a unique opportunity to confront our understanding of the dynamics of kinetic plasma turbulence, and its dissipation via collisionless damping mechanisms, with in situ spacecraft measurements. Significant effort has recently been focused on employing the gyrokinetic formalism to study the dissipation of turbulence in the solar wind, taking advantage of sophisticated numerical techniques developed for use in the fusion community. Here I will report on some of the most recent successes of this effort, in particular the first three-dimensional, nonlinear gyrokinetic simulation of plasma turbulence resolving scales from the ion to electron gyroradius with a realistic mass ratio, where all damping is provided by resolved physical mechanisms. Complementing this theoretical and numerical research program are experiments on the Large Plasma Device (LAPD) at UCLA to measure the nonlinear interactions between counterpropagating Alfven waves, the fundamental building block of Alfvenic plasma turbulence.

  150. Monday, April 9

    12:05 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speaker:  Noam Katz, University of Wisconsin - Madison
    "Stirring Unmagnetized Plasmas and Progress towards a Plasma Dynamo Experiment"

  151. Friday, March 30

    12:05 PM to 1:00 PM

    Midwest Mechanics Seminar

    1153 Mechanical Engineering Building

    Speaker:  Professor Gareth McKinley, Massachusetts Institute of Technology
    "Microfluidic Rheometry of Complex Fluids"
    Abstract: The development and growth of microfluidics has stimulated interest in the behavior of complex liquids in microscale geometries and provided a rich platform for rheometric investigations of non-Newtonian material phenomena at small scales. Microfluidic techniques present the rheologist with new opportunities for measurement of fluid properties, and enable the systematic investigation of strong elastic effects at very high deformation rates without the complications of fluid inertia. In this presentation we provide an overview of the use of microfluidic devices to measure bulk rheology and onset of viscoelastic flow instabilities in both shear and extensional flows, using a combination of local velocimetric imaging, mechanical measurements of pressure drop and full-field optical probes of flow-induced birefringence.  Steady and time-dependent flows of a range of dilute polymer solutions and wormlike micellar fluids are considered.   The ability to rapidly and precisely fabricate complex flow geometries also enables us to exploit the predictions of computational optimization and design, from first principles, an optimized shape cross-slot extensional rheometer (or OSCER) that achieves homogeneous planar extensional kinematics and large fluid strains. Local birefringence measurements along the stagnation streamlines combined with bulk measurements of the excess pressure drop across the device provide self-consistent estimates of the extensional viscosity over a wide range of deformation rates up to 1000 s-1. The results are also in close agreement with numerical simulations based on a finitely extensible non-linear elastic (FENE) dumbell model.
    Host/Contact:  Professor Jeff Giacomin, giacomin@wisc.edu  608-262-7473
    Co-sponsor:  Rheology Research Center

  152. Tuesday, March 27

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Dr. Heather J. MacLean Chichester   Idaho National Laboratory
    "Postirradiation Examination of High Burnup Metallic Fuels"
    Abstract:  Dr. Heather J. Maclean Chichester from Idaho National Laboratory will be visiting the Engineering Physics department on Tuesday, March 27th to deliver a Colloquium presentation on the destructive postirradiation examination of various alloys, including fission gas release, optical microscopy, and burnup analysis.
    Contact:  Professor Jake Blanchard   blanchard@engr.wisc.edu

  153. Monday, March 26

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Topic: Sherwood Fusion Theory Conference poster dry runs
    Note: there will be no Plasma Theory Seminar on April 2, 2012 due to the Sherwood Fusion Theory Conference, and there will be no seminar on April 9.

  154. Monday, March 26

    10:00 AM

    Special Seminar

    1045 Engineering Centers Building

    Speaker:  Jianwei Hu, Nuclear Nonproliferation Division, Los Alamos National Laboratory
    Collaborators:  Stephen J. Tobin and Howard O. Menlove, Nuclear Nonproliferation Division, Los Alamos National Laboratory
    "Developing the Californium Interrogation with Prompt Neutron Technique to Measure Fissile Content and to Detect Diversion in Spent Nuclear Fuel Assemblies"
    Abstract:  This talk mainly focuses on development of nondestructive assays (NDA) for spent fuel measurement. In the end, I would like to briefly discuss my PhD thesis work and my experience with a few nuclear codes, including MCNP5/X, MONTEBURNS, CINDER90, and NJOY.
    The majority of plutonium is stored in spent nuclear fuel assemblies. Presently, there is no means for directly measuring the mass of the plutonium in these assemblies by NDA. Since 2009 researchers at Los Alamos National Laboratory have been coordinating a multi-laboratory effort to develop new NDA techniques to quantify Pu in, and to detect diversion of fuel pins from, spent fuel assemblies. Over a dozen NDA techniques have been researched, and efforts have now turned to the construction of three or more integrated systems comprised of the most promising and complementary techniques. This talk will firstly discuss the needs for advanced NDA techniques for international safeguards and overview of the overall project. Then the focus will be moved onto a specific NDA technique that we developed during this process --  Californium Interrogation with Prompt Neutron (CIPN) technique.
    CIPN is a relatively low-cost and lightweight instrument, and it looks like a modified fork detector combined with an active interrogation source (252 Cf). Fission chambers were chosen as the neutron detectors because of their insensitivity to photon radiation. The design has been optimized so CIPN has almost uniform sensitivity to diversions at different locations across the assembly. A 100 µg 252 Cf source was proven strong enough to provide sufficiently high signal above background. The capability of CIPN was quantified against a virtual library of 64 spent fuel assemblies using MCNPX simulations. The CIPN assay comprises two measurements, a background count and an active count, without and with the presence of the Cf source respectively. The net signal is mainly due to multiplication of the Cf source neutrons; this multiplication is dependent on both the fissile content and the neutron absorbers present in the assembly. Two novel corrections have been introduced to account for the absorption caused by neutron absorbers. With the help of empirical fitting, the fissile content in a target spent fuel assembly can be determined from the CIPN signal. CIPN is also tested in a series of hypothesized diversion cases. Preliminary results show that CIPN can detect diversion of 8 or more fuel pins (3% of total mass) provided the count rate of baseline case was previously measured. Engineering design and conceptual experiment setup of CIPN is also discussed.
    In the end, a few minutes will be spent to briefly discuss my PhD thesis on fuel performance modeling of TRISO fuel, as well as several other projects to show my involvements with a few nuclear codes.

  155. Monday, March 26

    12:05 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speaker:  Carlos Paz-Soldan, University of Wisconsin - Madison
    "Stabilization of the Resistive Wall Mode and Error Field Modification by a Rotating Conducting Wall"
    Abstract:  The interaction of a rotating conducting wall with a linear plasma column and its resistive wall mode (RWM) instability is detailed. A rotating wall capable of routine operation at speeds of ~ 300 km/h was designed, manufactured, and assembled. The interaction of error fields with the rotating wall are shown to lead to asymmetries in wall rotation. Analytic theory is used to illustrate that the error field at a given wall velocity is complex and can often overcome the natural shielding of the wall. MHD mode-locking is found for the first time in a linear plasma column. A torque balance model which includes the effect of the error field, plasma rotation, and wall rotation is developed and applied to the experiment.  Asymmetry in wall rotation is also found in the torque balance, with one wall rotation direction eliminating the mode-locking bifurcations. Using locked and born-locked modes, the stabilizing effect of the rotating wall on the RWM is experimentally demonstrated. The rotating wall is found to decrease the locked mode growth rate and increase the RWM stable operation window to higher plasma current.

  156. Wednesday, March 21

    9:30 AM to 10:30 AM

    Special Seminar

    2065 Mechanical Engineering Building

    Speaker:  Dr. F. A. Garner, Radiation Effects Consulting, Richland, Washington
    "Second-Order Phenomena in Austenitic Internal Components Growing to First Order Importance at the Higher Damage Levels Associated with PWR Plant Life Extension to 60 or 80 Years"
    Abstract:  Austenitic stainless steels, especially AISI 304 and 316, form the core internals that frame and support the cores of pressurized water reactors. In some reactors alloys such as Inconel 600 or 718 were also used for selected in-core applications such as guide tubes and springs. The near-core portion of the baffle-former assembly receives relatively high neutron exposures (40-100 dpa) over a 40 year life-time. Extending the lifetime of these components to 60 or 80 years will lead to correspondingly higher damage exposures.
    Within the 40 year licensing period a number of issues of first-order importance have been addressed, especially embrittlement, IASCC and irradiation creep. A number of second-order issues have been recognized but not considered to be life-limiting or deleterious. However, the non-linear nature of a number of second-order processes gives cause to worry that they might become first-order with extension of PWR life-times.
    The first of these second-order process is the void swelling phenomenon which is clearly a non-linear and non- saturable process. The second of these second-order processes is the progressive promotion of the five naturally occurring isotopes of nickel to higher atomic weight via transmutation. One product of this transmutation sequence is the production of Ni-59, a non-naturally occurring isotope that continues to increase in concentration until a thermal neutron fluence of about 4 x 1022 n/cm2 has been reached. The consequences of the Ni-59 production are a very high and continuously accelerating production of helium and hydrogen, concurrent with a generally unrecognized increasing rate of atomic displacement and increased nuclear heating, the latter two consequences arising from the highly exothermic nature of the Ni-59 (n, α) and (n, p) reactions. These processes become increasingly important for higher nickel alloys such as Inconel 600 and 718.
    The third process is the now well-known tendency of hydrogen to be stored in helium-nucleated bubbles and voids, and for the increasing storage to promote formation of very high densities of bubbles not only in the matrix but also on grain boundaries. Cracks moving along grain boundaries or through the matrix will constantly be intersecting cavities filled with hydrogen with possible consequences on accelerated cracking.
    The fourth process is the generally unrecognized but progressive radiation-induced movement of 300 series steels toward stress-induced martensitic instability, especially at very high damage levels.
    These four processes will be shown in this paper to have already begun to reveal their growing presence. Based on the known parametric dependencies of these four processes it is expected that they will most likely interact in a very synergistic manner. These processes should be studied proactively before they become truly first-order in importance.
    Biography:  For four decades Frank Garner has played a prominent role in the international radiation damage and nuclear reactor communities as a technical contributor and a scientific leader. Dr. Garner received his B.Sc in Chemical Engineering, (1963) and D.Sc in Nuclear Engineering with Materials emphasis (1970) from the University of Virginia in Charlottsville.

  157. Tuesday, March 20

    3:45 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Dr. Frank Garner, Radiation Effects Consulting
    "Void Swelling and Irradiation Creep of Ferritic-Martensitic Alloys at Very High Radiation Doses"
    Abstract:  In a nuclear reactor, the steel making up the reactor is subject to intense radiation for long exposure times. The doses are measured in displacements per atoms (dpa). Doses in present reactors may be 100 dpa, and future reactor concepts envision doses as high as 600 dpa. A review is presented of recent high-dose irradiation studies on HT9 and EP-450 conducted in FFTF and BOR-60 with maximum doses of 200 and 163 dpa, respectively, and also on EP-450, EP-823 and EP-852 irradiated side-by side in BN-350 to doses of 61 dpa. Additionally data on MA957 are available from FFTF to ~100 dpa. Irradiation creep strains in these ferritic-martensitic steels have been found to be less by a factor of ~2 compared to austenitic steels, but creep strains are sometimes obscured by concurrent precipitation and recovery strains, often of opposite sign. Dispersoids in MA957 were found to reduce thermal creep at higher temperatures but not to reduce irradiation creep to doses of ~100 dpa. 
    Biography:  For four decades Frank Garner has played a prominent role in the international radiation damage and nuclear reactor communities as a technical contributor and a scientific leader. Dr. Garner received his B.Sc in Chemical Engineering, (1963) and D.Sc in Nuclear Engineering with Materials emphasis (1970) from the University of Virginia in Charlottsville.

  158. Monday, March 19

    12:05 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speaker:  Dr. Benjamin Chandran, University of New Hampshire
    "Alfven Wave Turbulence and the Origin of the Solar Wind"
    Abstract:  The origin of the solar wind is one of the most important unsolved problems in space physics. In this talk, I will describe one of the leading theories for the origin of the solar wind, which holds that the solar wind is powered by an outward flux of Alfven waves from the Sun. I will focus on two plasma-physics problems that arise in this theory. The first is the question of how Alfven-wave turbulence is affected by the non-WKB reflection of low-frequency Alfven waves in the inhomogeneous solar corona and solar wind. The second is the question of how low-frequency Alfven-wave turbulence can explain the perpendicular ion heating that is observed in the solar wind, even when the wave frequencies are too small to cause resonant cyclotron heating. I will also briefly discuss recent work that incorporates Alfven wave turbulence and the collisionless dissipation of this turbulence into a global, two-fluid solar wind model with temperature anisotropy.

  159. Monday, March 19

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  Joshua Sauppe, University of Wisconsin - Madison
    "Two Fluid Modeling of Current and Flow Relaxation in the Reversed-Field Pinch"

  160. Thursday, March 15

    3:45 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Dr. Elia Merzari,  Argonne National Laboratory
    "Three Dimensional Stability Analysis in Natural Convection Systems"
    Abstract:  Fluid flows are subject to a wide range of instabilities. The study and prediction of such instability by the means of analytical and/or numerical methods is an active branch of fluid dynamics. The presence of an instability may have a severe impact on the performance or behavior of systems and components. In particular, the presence of such instabilities in natural convection systems may have a significant impact on the design and operation of passive systems or reactors designed to operate without pumps.
    In the first part of this talk we will examine the classic one-dimensional stability theory of thermo-siphon loops (i.e., the prototype of natural circulation systems). In the second part of this talk we will examine methods to predict, quantify and influence a flow instability. The focus will be on the classic modal methods. In particular the attention will be on global linear stability analysis, where a general three-dimensional linear perturbation is superposed to the base flow field and the eignevalue-eigenfunction spectrum of the linear operator so determined, is computed.
    Biography:  Dr. Elia Merzari currently works at Argonne National Lab at the Nuclear Engineering Division. His current research focuses on passive cooling methods for next generation nuclear reactors. Prior to joining Argonne, Elia was a Postdoctoral Fellow at the Tokyo Institute of Technology. He received his B.S. in Engineering of Energy Systems and his M.S. in Nuclear Engineering from Milan Polytechnic University in Italy and his Ph.D. in Nuclear Engineering from Tokyo Institute of Technology.
    Contact: Darius Lisowski, president@atomicbadger.org 978-902-0771

  161. Monday, March 12

    12:05 PM

    Plasma Physics Seminar

    2535 Engineering Hall

    Speaker:  Dr. Ping Zhu, University of Wisconsin - Madison
    "Origin of Auroral Substorms: Trigger and Catalyst"

  162. Monday, March 12

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker:  M.J. Pueschel, University of Wisconsin - Madison
    "The High-beta Runaway: Magnetic Perturbations and Zonal Flows"

  163. Monday, March 5

    4:00 PM

    Plasma Theory Seminar

    514 Engineering Research Building

    Speaker: Daniel Carmody, University of Wisconsin - Madison
    "Gyrokinetic Modeling of Microinstabilities in the RFP"

  164. Monday, March 5

    12:00 PM

    Special Plasma Seminar

    2241 Chamberlin Hall

    Speaker: Dr. Mark Nornberg, University of Wisconsin - Madison
    "Using liquid metal experiments to test models of MHD turbulence"
    Abstract:  Experiments using liquid metals to demonstrate MHD instabilities like the generation of magnetic field through a dynamo or magnetically induced turbulence through the Magnetorotational Instability provide a wealth of information on MHD turbulence. Recent measurements of the correlated velocity and magnetic fluctuations on the Madison Dynamo Experiment reveal that simple mean-field models, assuming homogeneous and isotropic turbulence, describe the measured transport of magnetic field rather well. Turbulence in a rapidly rotating fluid, like that of an experiment designed to study the magnetorotational instability, has a strong anisotropy however which tends to confine the motions of the fluid to two-dimensional, wave-like turbulence. I will present some ideas for experiments using a rapidly rotating liquid metal to study the effects of magnetic fields on these waves and to test mean-field models for describing turbulent transport in these flows.

  165. Thursday, March 1

    12:00 PM

    Special Plasma Seminar

    4274 Chamberlin Hall

    Speaker: Dr. Eric Edlund, Princeton Plasma Physics Laboratory
    "Rotation and Turbulence in Laboratory and Astrophysical Systems"

  166. Tuesday, February 21

    4:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker:  Dr. John Kelly, U.S. Department of Energy
    Topic to be announced

  167. Thursday, February 16

    5:30 PM to 7:00 PM

    Engineering Physics Special Event

    1106 Mechanical Engineering Building

    Topic:   "Clean Energy America: Special Dialogue on Nuclear Energy"
    Multiple speakers present and discuss:  Clean Energy America will be visiting our university to engage in a special dialogue regarding nuclear energy. Their aim is to present the facts and answer questions about nuclear energy while raising awareness about clean energy alternatives. The visiting group, experts in nuclear energy from across the nation, is comprised of scientists and engineers from industry and national labs. Light refreshments will be provided. Registration is not required but it is preferred.
    Contact:  Darius Lisowski   president@atomicbadger.org

  168. Wednesday, February 1

    12:00 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker:  Dr. Ben Longmier, University of Houston
    "Ambipolar Ion Acceleration from Plasma Expansion through a Magnetic Nozzle and Near-Term Spacecraft Propulsion Applications"

  169. Tuesday, January 31

    4:00 PM to 5:00 PM

    Engineering Physics Colloquium

    106 Engineering Research Building

    Speaker: Professor Kenneth Czerwinski, University of Nevada - Las Vegas
    "Actinide Nitrides and Technetium Halides: Preparation and Characterization"

  170. Monday, January 30

    12:05 PM

    Plasma Physics Seminar

    2241 Chamberlin Hall

    Speaker: Dr. Kirk Flippo, Los Alamos National Laboratory
    "Fusion Cuisine: Mingling Inertial and Magnetic Fusion Concepts in High Energy Density Plasma Physics"

  171. Monday, January 23

    12:00 AM to 12:00 AM

    Spring 2012 instruction begins