ZENO: N-body and SPH Simulation Codes
Barnes, Joshua E.
2011-02-01
The ZENO software package integrates N-body and SPH simulation codes with a large array of programs to generate initial conditions and analyze numerical simulations. Written in C, the ZENO system is portable between Mac, Linux, and Unix platforms. It is in active use at the Institute for Astronomy (IfA), at NRAO, and possibly elsewhere. Zeno programs can perform a wide range of simulation and analysis tasks. While many of these programs were first created for specific projects, they embody algorithms of general applicability and embrace a modular design strategy, so existing code is easily applied to new tasks. Major elements of the system include: Structured data file utilities facilitate basic operations on binary data, including import/export of ZENO data to other systems.Snapshot generation routines create particle distributions with various properties. Systems with user-specified density profiles can be realized in collisionless or gaseous form; multiple spherical and disk components may be set up in mutual equilibrium.Snapshot manipulation routines permit the user to sift, sort, and combine particle arrays, translate and rotate particle configurations, and assign new values to data fields associated with each particle.Simulation codes include both pure N-body and combined N-body/SPH programs: Pure N-body codes are available in both uniprocessor and parallel versions.SPH codes offer a wide range of options for gas physics, including isothermal, adiabatic, and radiating models. Snapshot analysis programs calculate temporal averages, evaluate particle statistics, measure shapes and density profiles, compute kinematic properties, and identify and track objects in particle distributions.Visualization programs generate interactive displays and produce still images and videos of particle distributions; the user may specify arbitrary color schemes and viewing transformations.
GRADSPMHD: A parallel MHD code based on the SPH formalism
Vanaverbeke, S.; Keppens, R.; Poedts, S.
2014-03-01
We present GRADSPMHD, a completely Lagrangian parallel magnetohydrodynamics code based on the SPH formalism. The implementation of the equations of SPMHD in the “GRAD-h” formalism assembles known results, including the derivation of the discretized MHD equations from a variational principle, the inclusion of time-dependent artificial viscosity, resistivity and conductivity terms, as well as the inclusion of a mixed hyperbolic/parabolic correction scheme for satisfying the ∇ṡB→ constraint on the magnetic field. The code uses a tree-based formalism for neighbor finding and can optionally use the tree code for computing the self-gravity of the plasma. The structure of the code closely follows the framework of our parallel GRADSPH FORTRAN 90 code which we added previously to the CPC program library. We demonstrate the capabilities of GRADSPMHD by running 1, 2, and 3 dimensional standard benchmark tests and we find good agreement with previous work done by other researchers. The code is also applied to the problem of simulating the magnetorotational instability in 2.5D shearing box tests as well as in global simulations of magnetized accretion disks. We find good agreement with available results on this subject in the literature. Finally, we discuss the performance of the code on a parallel supercomputer with distributed memory architecture. Catalogue identifier: AERP_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AERP_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 620503 No. of bytes in distributed program, including test data, etc.: 19837671 Distribution format: tar.gz Programming language: FORTRAN 90/MPI. Computer: HPC cluster. Operating system: Unix. Has the code been vectorized or parallelized?: Yes, parallelized using MPI. RAM: ˜30 MB for a
A theory manual for multi-physics code coupling in LIME.
Energy Technology Data Exchange (ETDEWEB)
Belcourt, Noel; Bartlett, Roscoe Ainsworth; Pawlowski, Roger Patrick; Schmidt, Rodney Cannon; Hooper, Russell Warren
2011-03-01
The Lightweight Integrating Multi-physics Environment (LIME) is a software package for creating multi-physics simulation codes. Its primary application space is when computer codes are currently available to solve different parts of a multi-physics problem and now need to be coupled with other such codes. In this report we define a common domain language for discussing multi-physics coupling and describe the basic theory associated with multiphysics coupling algorithms that are to be supported in LIME. We provide an assessment of coupling techniques for both steady-state and time dependent coupled systems. Example couplings are also demonstrated.
Preliminary Coupling of MATRA Code for Multi-physics Analysis
International Nuclear Information System (INIS)
Kim, Seongjin; Choi, Jinyoung; Yang, Yongsik; Kwon, Hyouk; Hwang, Daehyun
2014-01-01
The boundary conditions such as the inlet temperature, mass flux, averaged heat flux, power distributions of the rods, and core geometry is given by constant values or functions of time. These conditions are separately calculated and provided by other codes, such as a neutronics or a system codes, into the MATRA code. In addition, the coupling of several codes in the different physics field is focused and embodied. In this study, multiphysics coupling methods were developed for a subchannel code (MATRA) with neutronics codes (MASTER, DeCART) and a fuel performance code (FRAPCON-3). Preliminary evaluation results for representative sample cases are presented. The MASTER and DeCART codes provide the power distribution of the rods in the core to the MATRA code. In case of the FRAPCON-3 code, the variation of the rod diameter induced by the thermal expansion is yielded and provided. The MATRA code transfers the thermal-hydraulic conditions that each code needs. Moreover, the coupling method with each code is described
Modular ORIGEN-S for multi-physics code systems
International Nuclear Information System (INIS)
Yesilyurt, Gokhan; Clarno, Kevin T.; Gauld, Ian C.; Galloway, Jack
2011-01-01
The ORIGEN-S code in the SCALE 6.0 nuclear analysis code suite is a well-validated tool to calculate the time-dependent concentrations of nuclides due to isotopic depletion, decay, and transmutation for many systems in a wide range of time scales. Application areas include nuclear reactor and spent fuel storage analyses, burnup credit evaluations, decay heat calculations, and environmental assessments. Although simple to use within the SCALE 6.0 code system, especially with the ORIGEN-ARP graphical user interface, it is generally complex to use as a component within an externally developed code suite because of its tight coupling within the infrastructure of the larger SCALE 6.0 system. The ORIGEN2 code, which has been widely integrated within other simulation suites, is no longer maintained by Oak Ridge National Laboratory (ORNL), has obsolete data, and has a relatively small validation database. Therefore, a modular version of the SCALE/ORIGEN-S code was developed to simplify its integration with other software packages to allow multi-physics nuclear code systems to easily incorporate the well-validated isotopic depletion, decay, and transmutation capability to perform realistic nuclear reactor and fuel simulations. SCALE/ORIGEN-S was extensively restructured to develop a modular version that allows direct access to the matrix solvers embedded in the code. Problem initialization and the solver were segregated to provide a simple application program interface and fewer input/output operations for the multi-physics nuclear code systems. Furthermore, new interfaces were implemented to access and modify the ORIGEN-S input variables and nuclear cross-section data through external drivers. Three example drivers were implemented, in the C, C++, and Fortran 90 programming languages, to demonstrate the modular use of the new capability. This modular version of SCALE/ORIGEN-S has been embedded within several multi-physics software development projects at ORNL, including
Modular ORIGEN-S for multi-physics code systems
Energy Technology Data Exchange (ETDEWEB)
Yesilyurt, Gokhan; Clarno, Kevin T.; Gauld, Ian C., E-mail: yesilyurtg@ornl.gov, E-mail: clarnokt@ornl.gov, E-mail: gauldi@ornl.gov [Oak Ridge National Laboratory, TN (United States); Galloway, Jack, E-mail: jack@galloways.net [Los Alamos National Laboratory, Los Alamos, NM (United States)
2011-07-01
The ORIGEN-S code in the SCALE 6.0 nuclear analysis code suite is a well-validated tool to calculate the time-dependent concentrations of nuclides due to isotopic depletion, decay, and transmutation for many systems in a wide range of time scales. Application areas include nuclear reactor and spent fuel storage analyses, burnup credit evaluations, decay heat calculations, and environmental assessments. Although simple to use within the SCALE 6.0 code system, especially with the ORIGEN-ARP graphical user interface, it is generally complex to use as a component within an externally developed code suite because of its tight coupling within the infrastructure of the larger SCALE 6.0 system. The ORIGEN2 code, which has been widely integrated within other simulation suites, is no longer maintained by Oak Ridge National Laboratory (ORNL), has obsolete data, and has a relatively small validation database. Therefore, a modular version of the SCALE/ORIGEN-S code was developed to simplify its integration with other software packages to allow multi-physics nuclear code systems to easily incorporate the well-validated isotopic depletion, decay, and transmutation capability to perform realistic nuclear reactor and fuel simulations. SCALE/ORIGEN-S was extensively restructured to develop a modular version that allows direct access to the matrix solvers embedded in the code. Problem initialization and the solver were segregated to provide a simple application program interface and fewer input/output operations for the multi-physics nuclear code systems. Furthermore, new interfaces were implemented to access and modify the ORIGEN-S input variables and nuclear cross-section data through external drivers. Three example drivers were implemented, in the C, C++, and Fortran 90 programming languages, to demonstrate the modular use of the new capability. This modular version of SCALE/ORIGEN-S has been embedded within several multi-physics software development projects at ORNL, including
An introduction to LIME 1.0 and its use in coupling codes for multiphysics simulations.
Energy Technology Data Exchange (ETDEWEB)
Belcourt, Noel; Pawlowski, Roger Patrick; Schmidt, Rodney Cannon; Hooper, Russell Warren
2011-11-01
LIME is a small software package for creating multiphysics simulation codes. The name was formed as an acronym denoting 'Lightweight Integrating Multiphysics Environment for coupling codes.' LIME is intended to be especially useful when separate computer codes (which may be written in any standard computer language) already exist to solve different parts of a multiphysics problem. LIME provides the key high-level software (written in C++), a well defined approach (with example templates), and interface requirements to enable the assembly of multiple physics codes into a single coupled-multiphysics simulation code. In this report we introduce important software design characteristics of LIME, describe key components of a typical multiphysics application that might be created using LIME, and provide basic examples of its use - including the customized software that must be written by a user. We also describe the types of modifications that may be needed to individual physics codes in order for them to be incorporated into a LIME-based multiphysics application.
An approach for coupled-code multiphysics core simulations from a common input
International Nuclear Information System (INIS)
Schmidt, Rodney; Belcourt, Kenneth; Hooper, Russell; Pawlowski, Roger; Clarno, Kevin; Simunovic, Srdjan; Slattery, Stuart; Turner, John; Palmtag, Scott
2015-01-01
Highlights: • We describe an approach for coupled-code multiphysics reactor core simulations. • The approach can enable tight coupling of distinct physics codes with a common input. • Multi-code multiphysics coupling and parallel data transfer issues are explained. • The common input approach and how the information is processed is described. • Capabilities are demonstrated on an eigenvalue and power distribution calculation. - Abstract: This paper describes an approach for coupled-code multiphysics reactor core simulations that is being developed by the Virtual Environment for Reactor Applications (VERA) project in the Consortium for Advanced Simulation of Light-Water Reactors (CASL). In this approach a user creates a single problem description, called the “VERAIn” common input file, to define and setup the desired coupled-code reactor core simulation. A preprocessing step accepts the VERAIn file and generates a set of fully consistent input files for the different physics codes being coupled. The problem is then solved using a single-executable coupled-code simulation tool applicable to the problem, which is built using VERA infrastructure software tools and the set of physics codes required for the problem of interest. The approach is demonstrated by performing an eigenvalue and power distribution calculation of a typical three-dimensional 17 × 17 assembly with thermal–hydraulic and fuel temperature feedback. All neutronics aspects of the problem (cross-section calculation, neutron transport, power release) are solved using the Insilico code suite and are fully coupled to a thermal–hydraulic analysis calculated by the Cobra-TF (CTF) code. The single-executable coupled-code (Insilico-CTF) simulation tool is created using several VERA tools, including LIME (Lightweight Integrating Multiphysics Environment for coupling codes), DTK (Data Transfer Kit), Trilinos, and TriBITS. Parallel calculations are performed on the Titan supercomputer at Oak
Ballabio, G.; Dipierro, G.; Veronesi, B.; Lodato, G.; Hutchison, M.; Laibe, G.; Price, D. J.
2018-06-01
We describe a new implementation of the one-fluid method in the SPH code PHANTOM to simulate the dynamics of dust grains in gas protoplanetary discs. We revise and extend previously developed algorithms by computing the evolution of a new fluid quantity that produces a more accurate and numerically controlled evolution of the dust dynamics. Moreover, by limiting the stopping time of uncoupled grains that violate the assumptions of the terminal velocity approximation, we avoid fatal numerical errors in mass conservation. We test and validate our new algorithm by running 3D SPH simulations of a large range of disc models with tightly and marginally coupled grains.
ALE3D: An Arbitrary Lagrangian-Eulerian Multi-Physics Code
Energy Technology Data Exchange (ETDEWEB)
Noble, Charles R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Anderson, Andrew T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Barton, Nathan R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bramwell, Jamie A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Capps, Arlie [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chang, Michael H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chou, Jin J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dawson, David M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Diana, Emily R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dunn, Timothy A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Faux, Douglas R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fisher, Aaron C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Greene, Patrick T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Heinz, Ines [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kanarska, Yuliya [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Khairallah, Saad A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Liu, Benjamin T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Margraf, Jon D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nichols, Albert L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nourgaliev, Robert N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Puso, Michael A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reus, James F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Robinson, Peter B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shestakov, Alek I. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Solberg, Jerome M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Taller, Daniel [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tsuji, Paul H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); White, Christopher A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); White, Jeremy L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2017-05-23
ALE3D is a multi-physics numerical simulation software tool utilizing arbitrary-Lagrangian- Eulerian (ALE) techniques. The code is written to address both two-dimensional (2D plane and axisymmetric) and three-dimensional (3D) physics and engineering problems using a hybrid finite element and finite volume formulation to model fluid and elastic-plastic response of materials on an unstructured grid. As shown in Figure 1, ALE3D is a single code that integrates many physical phenomena.
Development of a three dimension multi-physics code for molten salt fast reactor
International Nuclear Information System (INIS)
Cheng Maosong; Dai Zhimin
2014-01-01
Molten Salt Reactor (MSR) was selected as one of the six innovative nuclear reactors by the Generation IV International Forum (GIF). The circulating-fuel in the can-type molten salt fast reactor makes the neutronics and thermo-hydraulics of the reactor strongly coupled and different from that of traditional solid-fuel reactors. In the present paper: a new coupling model is presented that physically describes the inherent relations between the neutron flux, the delayed neutron precursor, the heat transfer and the turbulent flow. Based on the model, integrating nuclear data processing, CAD modeling, structured and unstructured mesh technology, data analysis and visualization application, a three dimension steady state simulation code system (MSR3DS) for the can-type molten salt fast reactor is developed and validated. In order to demonstrate the ability of the code, the three dimension distributions of the velocity, the neutron flux, the delayed neutron precursor and the temperature were obtained for the simplified MOlten Salt Advanced Reactor Transmuter (MOSART) using this code. The results indicate that the MSR3DS code can provide a feasible description of multi-physical coupling phenomena in can-type molten salt fast reactor. Furthermore, the code can well predict the flow effect of fuel salt and the transport effect of the turbulent diffusion. (authors)
Computation of Thermodynamic Equilibria Pertinent to Nuclear Materials in Multi-Physics Codes
Piro, Markus Hans Alexander
Nuclear energy plays a vital role in supporting electrical needs and fulfilling commitments to reduce greenhouse gas emissions. Research is a continuing necessity to improve the predictive capabilities of fuel behaviour in order to reduce costs and to meet increasingly stringent safety requirements by the regulator. Moreover, a renewed interest in nuclear energy has given rise to a "nuclear renaissance" and the necessity to design the next generation of reactors. In support of this goal, significant research efforts have been dedicated to the advancement of numerical modelling and computational tools in simulating various physical and chemical phenomena associated with nuclear fuel behaviour. This undertaking in effect is collecting the experience and observations of a past generation of nuclear engineers and scientists in a meaningful way for future design purposes. There is an increasing desire to integrate thermodynamic computations directly into multi-physics nuclear fuel performance and safety codes. A new equilibrium thermodynamic solver is being developed with this matter as a primary objective. This solver is intended to provide thermodynamic material properties and boundary conditions for continuum transport calculations. There are several concerns with the use of existing commercial thermodynamic codes: computational performance; limited capabilities in handling large multi-component systems of interest to the nuclear industry; convenient incorporation into other codes with quality assurance considerations; and, licensing entanglements associated with code distribution. The development of this software in this research is aimed at addressing all of these concerns. The approach taken in this work exploits fundamental principles of equilibrium thermodynamics to simplify the numerical optimization equations. In brief, the chemical potentials of all species and phases in the system are constrained by estimates of the chemical potentials of the system
A multi-physics code system based on ANC9, VIPRE-W and BOA for CIPS evaluation
International Nuclear Information System (INIS)
Zhang, B.; Sung, Y.; Secker, J.; Beard, C.; Hilton, P.; Wang, G.; Oelrich, R.; Karoutas, Z.; Sung, Y.
2011-01-01
This paper summarizes the development of a multi-physics code system for evaluation of Crud Induced Power Shift (CIPS) phenomenon experienced in some Pressurized Water Reactors (PWR). CIPS is an unexpected change in reactor core axial power distribution, caused by boron compounds in crud deposited in the high power fuel assemblies undergoing subcooled boiling. As part of the Consortium for Advanced Simulation of Light Water Reactors (CASL) sponsored by the US Department of Energy (DOE), this paper describes the initial linkage and application of a multi-physics code system ANC9/VIPRE-W/BOA for evaluating changes in core power distributions due to boron deposited in crud. The initial linkage of the code system along with the application results will be the base for the future CASL development. (author)
A multi-physics code system based on ANC9, VIPRE-W and BOA for CIPS evaluation
Energy Technology Data Exchange (ETDEWEB)
Zhang, B.; Sung, Y.; Secker, J.; Beard, C.; Hilton, P.; Wang, G.; Oelrich, R.; Karoutas, Z.; Sung, Y. [Westinghouse Electric Company LLC, Pittsburgh (United States)
2011-07-01
This paper summarizes the development of a multi-physics code system for evaluation of Crud Induced Power Shift (CIPS) phenomenon experienced in some Pressurized Water Reactors (PWR). CIPS is an unexpected change in reactor core axial power distribution, caused by boron compounds in crud deposited in the high power fuel assemblies undergoing subcooled boiling. As part of the Consortium for Advanced Simulation of Light Water Reactors (CASL) sponsored by the US Department of Energy (DOE), this paper describes the initial linkage and application of a multi-physics code system ANC9/VIPRE-W/BOA for evaluating changes in core power distributions due to boron deposited in crud. The initial linkage of the code system along with the application results will be the base for the future CASL development. (author)
Development of multi-physics code systems based on the reactor dynamics code DYN3D
Energy Technology Data Exchange (ETDEWEB)
Kliem, Soeren; Gommlich, Andre; Grahn, Alexander; Rohde, Ulrich [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany); Schuetze, Jochen [ANSYS Germany GmbH, Darmstadt (Germany); Frank, Thomas [ANSYS Germany GmbH, Otterfing (Germany); Gomez Torres, Armando M.; Sanchez Espinoza, Victor Hugo [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany)
2011-07-15
The reactor dynamics code DYN3D has been coupled with the CFD code ANSYS CFX and the 3D thermal hydraulic core model FLICA4. In the coupling with ANSYS CFX, DYN3D calculates the neutron kinetics and the fuel behavior including the heat transfer to the coolant. The physical data interface between the codes is the volumetric heat release rate into the coolant. In the coupling with FLICA4 only the neutron kinetics module of DYN3D is used. Fluid dynamics and related transport phenomena in the reactor's coolant and fuel behavior is calculated by FLICA4. The correctness of the coupling of DYN3D with both thermal hydraulic codes was verified by the calculation of different test problems. These test problems were set-up in such a way that comparison with the DYN3D stand-alone code was possible. This included steady-state and transient calculations of a mini-core consisting of nine real-size PWR fuel assemblies with ANSYS CFX/DYN3D as well as mini-core and a full core steady-state calculation using FLICA4/DYN3D. (orig.)
Development of multi-physics code systems based on the reactor dynamics code DYN3D
International Nuclear Information System (INIS)
Kliem, Soeren; Gommlich, Andre; Grahn, Alexander; Rohde, Ulrich; Schuetze, Jochen; Frank, Thomas; Gomez Torres, Armando M.; Sanchez Espinoza, Victor Hugo
2011-01-01
The reactor dynamics code DYN3D has been coupled with the CFD code ANSYS CFX and the 3D thermal hydraulic core model FLICA4. In the coupling with ANSYS CFX, DYN3D calculates the neutron kinetics and the fuel behavior including the heat transfer to the coolant. The physical data interface between the codes is the volumetric heat release rate into the coolant. In the coupling with FLICA4 only the neutron kinetics module of DYN3D is used. Fluid dynamics and related transport phenomena in the reactor's coolant and fuel behavior is calculated by FLICA4. The correctness of the coupling of DYN3D with both thermal hydraulic codes was verified by the calculation of different test problems. These test problems were set-up in such a way that comparison with the DYN3D stand-alone code was possible. This included steady-state and transient calculations of a mini-core consisting of nine real-size PWR fuel assemblies with ANSYS CFX/DYN3D as well as mini-core and a full core steady-state calculation using FLICA4/DYN3D. (orig.)
International Nuclear Information System (INIS)
Salko, Robert K.; Schmidt, Rodney C.; Avramova, Maria N.
2015-01-01
Highlights: • COBRA-TF was adopted by the Consortium for Advanced Simulation of LWRs. • We have improved code performance to support running large-scale LWR simulations. • Code optimization has led to reductions in execution time and memory usage. • An MPI parallelization has reduced full-core simulation time from days to minutes. - Abstract: This paper describes major improvements to the computational infrastructure of the CTF subchannel code so that full-core, pincell-resolved (i.e., one computational subchannel per real bundle flow channel) simulations can now be performed in much shorter run-times, either in stand-alone mode or as part of coupled-code multi-physics calculations. These improvements support the goals of the Department Of Energy Consortium for Advanced Simulation of Light Water Reactors (CASL) Energy Innovation Hub to develop high fidelity multi-physics simulation tools for nuclear energy design and analysis. A set of serial code optimizations—including fixing computational inefficiencies, optimizing the numerical approach, and making smarter data storage choices—are first described and shown to reduce both execution time and memory usage by about a factor of ten. Next, a “single program multiple data” parallelization strategy targeting distributed memory “multiple instruction multiple data” platforms utilizing domain decomposition is presented. In this approach, data communication between processors is accomplished by inserting standard Message-Passing Interface (MPI) calls at strategic points in the code. The domain decomposition approach implemented assigns one MPI process to each fuel assembly, with each domain being represented by its own CTF input file. The creation of CTF input files, both for serial and parallel runs, is also fully automated through use of a pressurized water reactor (PWR) pre-processor utility that uses a greatly simplified set of user input compared with the traditional CTF input. To run CTF in
Energy Technology Data Exchange (ETDEWEB)
Matthew Ellis; Derek Gaston; Benoit Forget; Kord Smith
2011-07-01
In recent years the use of Monte Carlo methods for modeling reactors has become feasible due to the increasing availability of massively parallel computer systems. One of the primary challenges yet to be fully resolved, however, is the efficient and accurate inclusion of multiphysics feedback in Monte Carlo simulations. The research in this paper presents a preliminary coupling of the open source Monte Carlo code OpenMC with the open source Multiphysics Object-Oriented Simulation Environment (MOOSE). The coupling of OpenMC and MOOSE will be used to investigate efficient and accurate numerical methods needed to include multiphysics feedback in Monte Carlo codes. An investigation into the sensitivity of Doppler feedback to fuel temperature approximations using a two dimensional 17x17 PWR fuel assembly is presented in this paper. The results show a functioning multiphysics coupling between OpenMC and MOOSE. The coupling utilizes Functional Expansion Tallies to accurately and efficiently transfer pin power distributions tallied in OpenMC to unstructured finite element meshes used in MOOSE. The two dimensional PWR fuel assembly case also demonstrates that for a simplified model the pin-by-pin doppler feedback can be adequately replicated by scaling a representative pin based on pin relative powers.
International Nuclear Information System (INIS)
Donkor, M. O.
2013-06-01
Computational fluid dynamics (CFD) technique was adopted to investigate the hydrodynamics of gold leaching tanks. Comsol multiphysics code 3.4 provided the platform for modelling and simulation of the flow pattern of the gold leaching process. The impeller motion was integrated in the geometry using the simplified numerical method technique. The k-ε model was used to solve the Reynolds-averaged Navier-Stokes equations and velocity distributions in the vertical and horizontal section in the tank was obtained. It was found that the flow distribution in the simulated flow field was consistent with the characteristic down pumping flow pattern of the axial impellers. The convergence of the iterative procedure was tested and reasonable predictions were achieved for an industrial reactor. There were significant variations in velocity magnitudes with the impeller discharge region recording the highest. CFD modelling was consistent with the tracer test results and demonstrated the use of reactors active volume. The obtained CFD results showed a good agreement with literature information. Because CFD is capable of predicting the complete velocity distribution and simulating the tracer experiment in a tank, it provided a good alternative to carry out resistance time distribution (RDT) studies. CFD modelling was useful and informative tool for analyzing problematic hydrodynamics of gold leaching tanks and for the design of theoretical corrective measures and can be extended to other plants like water treatment plant and oil processing plant. (author)
The multi-physics, user-friendly gas-dynamics code Visual Tsunami 2.0
International Nuclear Information System (INIS)
Debonnel, C. S.; Trubov, L.; Zeballos, C. A.; Peterson, P. F.
2007-01-01
Since the early 1990's, the series of simulation code known as TSUNAMI has been the main tool employed to explore gas dynamics phenomena in thick-liquid protected inertial fusion target chambers. The applicability and user-friendliness of the code was recently extended through a set of MATLAB pre- and post-processing tools and graphical user interfaces [1]. Geometry, initial, and boundary conditions can be specified from within AutoCAD through a set of in-house AutoLISP graphical user interfaces. A novel MATLAB core was recently developed and tested, and is now routinely used with the user-friendly pre- and post-processors [2]. An overview of Visual Tsunami 2.0, the latest version of the code, is presented here. (authors)
Computation of thermodynamic equilibria of nuclear materials in multi-physics codes
International Nuclear Information System (INIS)
Piro, M.H.; Lewis, B.J.; Thompson, W.T.; Simunovic, S.; Besmann, T.M.
2011-01-01
A new equilibrium thermodynamic solver is being developed with the primary impetus of direct integration into nuclear fuel performance and safety codes to provide improved predictions of fuel behavior. This solver is intended to provide boundary conditions and material properties for continuum transport calculations. There are several legitimate concerns with the use of existing commercial thermodynamic codes: 1) licensing entanglements associated with code distribution, 2) computational performance, and 3) limited capabilities of handling large multi-component systems of interest to the nuclear industry. The development of this solver is specifically aimed at addressing these concerns. In support of this goal, a new numerical algorithm for computing chemical equilibria is presented which is not based on the traditional steepest descent method or 'Gibbs energy minimization' technique. This new approach exploits fundamental principles of equilibrium thermodynamics, which simplifies the optimization equations. The chemical potentials of all species and phases in the system are constrained by the system chemical potentials, and the objective is to minimize the residuals of the mass balance equations. Several numerical advantages are achieved through this simplification, as described in this paper. (author)
A program code generator for multiphysics biological simulation using markup languages.
Amano, Akira; Kawabata, Masanari; Yamashita, Yoshiharu; Rusty Punzalan, Florencio; Shimayoshi, Takao; Kuwabara, Hiroaki; Kunieda, Yoshitoshi
2012-01-01
To cope with the complexity of the biological function simulation models, model representation with description language is becoming popular. However, simulation software itself becomes complex in these environment, thus, it is difficult to modify the simulation conditions, target computation resources or calculation methods. In the complex biological function simulation software, there are 1) model equations, 2) boundary conditions and 3) calculation schemes. Use of description model file is useful for first point and partly second point, however, third point is difficult to handle for various calculation schemes which is required for simulation models constructed from two or more elementary models. We introduce a simulation software generation system which use description language based description of coupling calculation scheme together with cell model description file. By using this software, we can easily generate biological simulation code with variety of coupling calculation schemes. To show the efficiency of our system, example of coupling calculation scheme with three elementary models are shown.
International Nuclear Information System (INIS)
Fiorina, C.; Mikityuk, K.
2015-01-01
A new multi-physics solver for nuclear reactor analysis, named GeN-Foam (Generalized Nuclear Foam), has been developed by the FAST group at the Paul Scherrer Institut. It is based on OpenFOAM and has been developed for the multi-physics transient analyses of pin-based (e.g., liquid metal Fast Reactors, Light Water Reactors) or homogeneous (e.g., fast spectrum Molten Salt Reactors) nuclear reactors. It includes solutions of coarse or fine mesh thermal-hydraulics, thermal-mechanics and neutron diffusion. In particular, thermal-hydraulics solution can combine on the same mesh both a traditional RANS model and a porous medium model, depending on the desired degree of approximation for each region. In case the active reactor core is modeled as a porous medium, a simple sub-solver computes the sub-scale radial temperature profiles in fuel and cladding. The mesh used for neutronics calculations is deformed according to the displacement field predicted by the thermal-mechanics solver, thus allowing for a direct prediction of expansion-related feedback effects in Fast Reactors. To limit computational requirements, GeN-Foam permits the use of three different unstructured meshes for thermal-hydraulics, thermal-mechanics and neutron diffusion. For the same reason, an adaptive time step is employed. The different equations can be solved altogether or selectively included. In this work, GeN-Foam is applied to the analysis of the European Sodium Fast Reactor (ESFR). In particular, a 3-D model of the ESFR core is set up employing a coarse-mesh porous-medium approach for the thermal-hydraulics. The reactor steady-state and different accidental transients are investigated to offer an overview of GeN-Foam use and capabilities, as well as to preliminarily investigate the impact of a relatively accurate thermal-mechanic treatment on the predicted ESFR behavior. A code-to-code benchmark against the TRACE system code is performed to verify the adequacy of the results provided by the new
Extensible, Reusable, and Reproducible Computing: A Case Study of PySPH
International Nuclear Information System (INIS)
Ramachandran, Prabhu
2016-01-01
In this work, the Smoothed Particle Hydrodynamics (SPH) technique is considered as an example of a typical computational research area. PySPH is an open source framework for SPH computations. PySPH is designed to be easy to use. The framework allows a user to implement an entire simulation in pure Python. It is designed to make it easy for scientists to reuse their code and extend the work of others. These important features allow PySPH to facilitate reproducible computational research. Based on the experience with PySPH, general recommendations are suggested for other computational researchers. (paper)
Simulating the formation and evolution of galaxies with EvoL, the Padova N-body Tree-SPH code
International Nuclear Information System (INIS)
Merlin, E.; Chiosi, C.; Grassi, T.; Buonomo, U.; Chinellato, S.
2009-01-01
The importance of numerical simulations in astrophysics is constantly growing, because of the complexity, the multi-scaling properties and the non-linearity of many physical phenomena. In particular, cosmological and galaxy-sized simulations of structure formation have cast light on different aspects, giving answers to many questions, but raising a number of new issues to be investigated. Over the last decade, great effort has been devoted in Padova to develop a tool explicitly designed to study the problem of galaxy formation and evolution, with particular attention to the early-type ones. To this aim, many simulations have been run on CINECA supercomputers (see publications list below). The next step is the new release of EvoL, a Fortran N-body code capable to follow in great detail many different aspects of stellar, interstellar and cosmological physics. In particular, special care has been paid to the properties of stars and their interplay with the surrounding interstellar medium (ISM), as well as to the multiphase nature of the ISM, to the setting of the initial and boundary conditions, and to the correct description of gas physics via modern formulations of the classical Smoothed Particle Hydrodynamics algorithms. Moreover, a powerful tool to compare numerical predictions with observables has been developed, self-consistently closing the whole package. A library of new simulations, run with EvoL on CINECA supercomputers, is to be built in the next years, while new physics, including magnetic properties of matter and more exotic energy feedback effects, is to be added.
The SPH homogeneization method
International Nuclear Information System (INIS)
Kavenoky, Alain
1978-01-01
The homogeneization of a uniform lattice is a rather well understood topic while difficult problems arise if the lattice becomes irregular. The SPH homogeneization method is an attempt to generate homogeneized cross sections for an irregular lattice. Section 1 summarizes the treatment of an isolated cylindrical cell with an entering surface current (in one velocity theory); Section 2 is devoted to the extension of the SPH method to assembly problems. Finally Section 3 presents the generalisation to general multigroup problems. Numerical results are obtained for a PXR rod bundle assembly in Section 4
Numerical simulation of lava flow using a GPU SPH model
Directory of Open Access Journals (Sweden)
Eugenio Rustico
2011-12-01
Full Text Available A smoothed particle hydrodynamics (SPH method for lava-flow modeling was implemented on a graphical processing unit (GPU using the compute unified device architecture (CUDA developed by NVIDIA. This resulted in speed-ups of up to two orders of magnitude. The three-dimensional model can simulate lava flow on a real topography with free-surface, non-Newtonian fluids, and with phase change. The entire SPH code has three main components, neighbor list construction, force computation, and integration of the equation of motion, and it is computed on the GPU, fully exploiting the computational power. The simulation speed achieved is one to two orders of magnitude faster than the equivalent central processing unit (CPU code. This GPU implementation of SPH allows high resolution SPH modeling in hours and days, rather than in weeks and months, on inexpensive and readily available hardware.
Application of the SPH method in nodal diffusion analyses of SFR cores
Energy Technology Data Exchange (ETDEWEB)
Nikitin, Evgeny; Fridman, Emil [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Reactor Safety; Mikityuk, K. [Paul Scherrer Institut, Villigen (Switzerland)
2016-07-01
The current study investigated the potential of the SPH method, applied to correct the few-group XS produced by Serpent, to further improve the accuracy of the nodal diffusion solutions. The procedure for the generation of SPH-corrected few-group XS is presented in the paper. The performance of the SPH method was tested on a large oxide SFR core from the OECD/NEA SFR benchmark. The reference SFR core was modeled with the DYN3D and PARCS nodal diffusion codes using the SPH-corrected few-group XS generated by Serpent. The nodal diffusion results obtained with and without SPH correction were compared to the reference full-core Serpent MC solution. It was demonstrated that the application of the SPH method improves the accuracy of the nodal diffusion solutions, particularly for the rodded core state.
Synthetic Observations of the HI Line in SPH-Simulated Spiral Galaxies
Douglas, Kevin A.; Acreman, David; Dobbs, Clare; Brunt, Chris
2009-01-01
Using the radiative transfer code Torus, we produce spectral-line cubes of the predicted HI profile from global SPH simulations of spiral galaxies. Torus grids the SPH galaxy using Adaptive Mesh Refinement, then applies a ray-tracing method to infer the HI profile along the line(s) of sight. The
Energy Technology Data Exchange (ETDEWEB)
Campbell, Michael T. [Illinois Rocstar LLC, Champaign, IL (United States); Safdari, Masoud [Illinois Rocstar LLC, Champaign, IL (United States); Kress, Jessica E. [Illinois Rocstar LLC, Champaign, IL (United States); Anderson, Michael J. [Illinois Rocstar LLC, Champaign, IL (United States); Horvath, Samantha [Illinois Rocstar LLC, Champaign, IL (United States); Brandyberry, Mark D. [Illinois Rocstar LLC, Champaign, IL (United States); Kim, Woohyun [Illinois Rocstar LLC, Champaign, IL (United States); Sarwal, Neil [Illinois Rocstar LLC, Champaign, IL (United States); Weisberg, Brian [Illinois Rocstar LLC, Champaign, IL (United States)
2016-10-15
The project described in this report constructed and exercised an innovative multiphysics coupling toolkit called the Illinois Rocstar MultiPhysics Application Coupling Toolkit (IMPACT). IMPACT is an open source, flexible, natively parallel infrastructure for coupling multiple uniphysics simulation codes into multiphysics computational systems. IMPACT works with codes written in several high-performance-computing (HPC) programming languages, and is designed from the beginning for HPC multiphysics code development. It is designed to be minimally invasive to the individual physics codes being integrated, and has few requirements on those physics codes for integration. The goal of IMPACT is to provide the support needed to enable coupling existing tools together in unique and innovative ways to produce powerful new multiphysics technologies without extensive modification and rewrite of the physics packages being integrated. There are three major outcomes from this project: 1) construction, testing, application, and open-source release of the IMPACT infrastructure, 2) production of example open-source multiphysics tools using IMPACT, and 3) identification and engagement of interested organizations in the tools and applications resulting from the project. This last outcome represents the incipient development of a user community and application echosystem being built using IMPACT. Multiphysics coupling standardization can only come from organizations working together to define needs and processes that span the space of necessary multiphysics outcomes, which Illinois Rocstar plans to continue driving toward. The IMPACT system, including source code, documentation, and test problems are all now available through the public gitHUB.org system to anyone interested in multiphysics code coupling. Many of the basic documents explaining use and architecture of IMPACT are also attached as appendices to this document. Online HTML documentation is available through the gitHUB site
Parallel multiphysics algorithms and software for computational nuclear engineering
International Nuclear Information System (INIS)
Gaston, D; Hansen, G; Kadioglu, S; Knoll, D A; Newman, C; Park, H; Permann, C; Taitano, W
2009-01-01
There is a growing trend in nuclear reactor simulation to consider multiphysics problems. This can be seen in reactor analysis where analysts are interested in coupled flow, heat transfer and neutronics, and in fuel performance simulation where analysts are interested in thermomechanics with contact coupled to species transport and chemistry. These more ambitious simulations usually motivate some level of parallel computing. Many of the coupling efforts to date utilize simple code coupling or first-order operator splitting, often referred to as loose coupling. While these approaches can produce answers, they usually leave questions of accuracy and stability unanswered. Additionally, the different physics often reside on separate grids which are coupled via simple interpolation, again leaving open questions of stability and accuracy. Utilizing state of the art mathematics and software development techniques we are deploying next generation tools for nuclear engineering applications. The Jacobian-free Newton-Krylov (JFNK) method combined with physics-based preconditioning provide the underlying mathematical structure for our tools. JFNK is understood to be a modern multiphysics algorithm, but we are also utilizing its unique properties as a scale bridging algorithm. To facilitate rapid development of multiphysics applications we have developed the Multiphysics Object-Oriented Simulation Environment (MOOSE). Examples from two MOOSE-based applications: PRONGHORN, our multiphysics gas cooled reactor simulation tool and BISON, our multiphysics, multiscale fuel performance simulation tool will be presented.
Multiphysics simulations: Challenges and opportunities
Keyes, David E.; McInnes, Lois Curfman; Woodward, Carol S.; Gropp, William D.; Myra, Eric S.; Pernice, Michael; Bell, John B.; Brown, Jed; Clo, Alain M.; Connors, Jeffrey Mark; Constantinescu, Emil M.; Estep, Donald J.; Evans, Katherine J.; Farhat, Charbel H.; Hakim, Ammar H.; Hammond, Glenn E.; Hansen, Glen A.; Hill, Judith C.; Isaac, Tobin; Jiao, Xiangmin; Jordan, Kirk E.; Kaushik, Dinesh K.; Kaxiras, Efthimios; Koniges, Alice E.; Lee, Kihwan; Lott, Aaron; Lu, Qiming; Magerlein, John H.; Maxwell, Reed M.; McCourt, Michael J.; Mehl, Miriam; Pawlowski, Roger P.; Randles, Amanda Peters; Reynolds, Daniel R.; Riviè re, Bé atrice M.; Rü de, Ulrich; Scheibe, Timothy D.; Shadid, John N.; Sheehan, Brendan; Shephard, Mark S.; Siegel, Andrew R.; Smith, Barry F.; Tang, Xianzhu; Wilson, Cian R G; Wohlmuth, Barbara Ian
2013-01-01
We consider multiphysics applications from algorithmic and architectural perspectives, where "algorithmic" includes both mathematical analysis and computational complexity, and "architectural" includes both software and hardware environments. Many diverse multiphysics applications can be reduced, en route to their computational simulation, to a common algebraic coupling paradigm. Mathematical analysis of multiphysics coupling in this form is not always practical for realistic applications, but model problems representative of applications discussed herein can provide insight. A variety of software frameworks for multiphysics applications have been constructed and refined within disciplinary communities and executed on leading-edge computer systems. We examine several of these, expose some commonalities among them, and attempt to extrapolate best practices to future systems. From our study, we summarize challenges and forecast opportunities. © The Author(s) 2012.
Multiphysics simulations: Challenges and opportunities
Keyes, David E.
2013-02-01
We consider multiphysics applications from algorithmic and architectural perspectives, where "algorithmic" includes both mathematical analysis and computational complexity, and "architectural" includes both software and hardware environments. Many diverse multiphysics applications can be reduced, en route to their computational simulation, to a common algebraic coupling paradigm. Mathematical analysis of multiphysics coupling in this form is not always practical for realistic applications, but model problems representative of applications discussed herein can provide insight. A variety of software frameworks for multiphysics applications have been constructed and refined within disciplinary communities and executed on leading-edge computer systems. We examine several of these, expose some commonalities among them, and attempt to extrapolate best practices to future systems. From our study, we summarize challenges and forecast opportunities. © The Author(s) 2012.
Multiphysics simulations: challenges and opportunities.
Energy Technology Data Exchange (ETDEWEB)
Keyes, D.; McInnes, L. C.; Woodward, C.; Gropp, W.; Myra, E.; Pernice, M. (Mathematics and Computer Science); (KAUST and Columbia Univ.); (Lawrence Livermore National Laboratory); (Univ. of Illinois at Urbana-Champaign); (Univ. of Mich.); (Idaho National Lab.)
2012-11-29
This report is an outcome of the workshop Multiphysics Simulations: Challenges and Opportunities, sponsored by the Institute of Computing in Science (ICiS). Additional information about the workshop, including relevant reading and presentations on multiphysics issues in applications, algorithms, and software, is available via https://sites.google.com/site/icismultiphysics2011/. We consider multiphysics applications from algorithmic and architectural perspectives, where 'algorithmic' includes both mathematical analysis and computational complexity and 'architectural' includes both software and hardware environments. Many diverse multiphysics applications can be reduced, en route to their computational simulation, to a common algebraic coupling paradigm. Mathematical analysis of multiphysics coupling in this form is not always practical for realistic applications, but model problems representative of applications discussed herein can provide insight. A variety of software frameworks for multiphysics applications have been constructed and refined within disciplinary communities and executed on leading-edge computer systems. We examine several of these, expose some commonalities among them, and attempt to extrapolate best practices to future systems. From our study, we summarize challenges and forecast opportunities. We also initiate a modest suite of test problems encompassing features present in many applications.
A hybrid Lagrangian Voronoi-SPH scheme
Fernandez-Gutierrez, D.; Souto-Iglesias, A.; Zohdi, T. I.
2017-11-01
A hybrid Lagrangian Voronoi-SPH scheme, with an explicit weakly compressible formulation for both the Voronoi and SPH sub-domains, has been developed. The SPH discretization is substituted by Voronoi elements close to solid boundaries, where SPH consistency and boundary conditions implementation become problematic. A buffer zone to couple the dynamics of both sub-domains is used. This zone is formed by a set of particles where fields are interpolated taking into account SPH particles and Voronoi elements. A particle may move in or out of the buffer zone depending on its proximity to a solid boundary. The accuracy of the coupled scheme is discussed by means of a set of well-known verification benchmarks.
Engineering Multiphysics Research
Directory of Open Access Journals (Sweden)
Tom Eppes
2011-05-01
Full Text Available This paper describes an engineering undergraduate course that covers the methods and techniques of multiphysics modeling. Students become active participants in analysis and discovery by being challenged to solve a sequence of problems related to high priority technology areas. Projects range from power systems and thermal control of habitats to autonomous flight systems and harsh environment electronics. Working in a cooperative learning environment, teams encounter a series of assignments that build on existing skills while gradually expanding their knowledge and expertise in disciplines outside of their own. This project-based approach employs a scaffolding structure with assignments organized in progressively challenging modules supported by mentoring. Each project begins with a problem definition which requires consideration of factors and influences beyond a single discipline. Solution development then moves to setting material properties, boundary constraints and including the necessary physics engines. For many students, this is the first in depth exposure to problems with specialized terminologies, driving equations and limiting conditions. Lastly, solving and post processing are addressed exploring steady state, time-variant, frequency response, optimization and sensitivity methods. The paper discusses the teaching and learning strategies, course structure, outcome assessment and project examples.
A reformulation of the transport-transport SPH equivalence technique
Energy Technology Data Exchange (ETDEWEB)
Hebert, A., E-mail: alain.hebert@polymtl.ca [Ecole Polytechnique de Montreal, Montreal, QC (Canada)
2015-07-01
The superhomogeneisation (SPH) equivalence technique is a correction procedure based on equivalence factors. These equivalence factors are computed in such a way that a macro calculation made over a macro region and a coarse energy group with a simplified transport operator leads to the same leakage and reaction rates as a reference calculation performed without homogenization and with a fine group discretization. The situation where the macro calculation is performed with diffusion theory is a well understood and a common application of the technique. However, the case where the macro calculation is performed in transport theory is more complex and the SPH technique was reformulated in order to take into account the angular parity of the flux moments and cross sections. We found that the general rule to multiply all cross sections by a SPH factor and to divide all flux moment by the same factor is not valid. A new correction strategy is proposed to deal with transport-theory macro calculations. The strategy is slightly different whether or not the macro calculation is performed with a spherical harmonics (PN or SPN) discretization. The new approach was implemented in the DRAGON lattice code. Numerical results are comparing the classical and reformulated techniques. (author)
A reformulation of the transport-transport SPH equivalence technique
International Nuclear Information System (INIS)
Hebert, A.
2015-01-01
The superhomogeneisation (SPH) equivalence technique is a correction procedure based on equivalence factors. These equivalence factors are computed in such a way that a macro calculation made over a macro region and a coarse energy group with a simplified transport operator leads to the same leakage and reaction rates as a reference calculation performed without homogenization and with a fine group discretization. The situation where the macro calculation is performed with diffusion theory is a well understood and a common application of the technique. However, the case where the macro calculation is performed in transport theory is more complex and the SPH technique was reformulated in order to take into account the angular parity of the flux moments and cross sections. We found that the general rule to multiply all cross sections by a SPH factor and to divide all flux moment by the same factor is not valid. A new correction strategy is proposed to deal with transport-theory macro calculations. The strategy is slightly different whether or not the macro calculation is performed with a spherical harmonics (PN or SPN) discretization. The new approach was implemented in the DRAGON lattice code. Numerical results are comparing the classical and reformulated techniques. (author)
SPHYNX: an accurate density-based SPH method for astrophysical applications
Cabezón, R. M.; García-Senz, D.; Figueira, J.
2017-10-01
Aims: Hydrodynamical instabilities and shocks are ubiquitous in astrophysical scenarios. Therefore, an accurate numerical simulation of these phenomena is mandatory to correctly model and understand many astrophysical events, such as supernovas, stellar collisions, or planetary formation. In this work, we attempt to address many of the problems that a commonly used technique, smoothed particle hydrodynamics (SPH), has when dealing with subsonic hydrodynamical instabilities or shocks. To that aim we built a new SPH code named SPHYNX, that includes many of the recent advances in the SPH technique and some other new ones, which we present here. Methods: SPHYNX is of Newtonian type and grounded in the Euler-Lagrange formulation of the smoothed-particle hydrodynamics technique. Its distinctive features are: the use of an integral approach to estimating the gradients; the use of a flexible family of interpolators called sinc kernels, which suppress pairing instability; and the incorporation of a new type of volume element which provides a better partition of the unity. Unlike other modern formulations, which consider volume elements linked to pressure, our volume element choice relies on density. SPHYNX is, therefore, a density-based SPH code. Results: A novel computational hydrodynamic code oriented to Astrophysical applications is described, discussed, and validated in the following pages. The ensuing code conserves mass, linear and angular momentum, energy, entropy, and preserves kernel normalization even in strong shocks. In our proposal, the estimation of gradients is enhanced using an integral approach. Additionally, we introduce a new family of volume elements which reduce the so-called tensile instability. Both features help to suppress the damp which often prevents the growth of hydrodynamic instabilities in regular SPH codes. Conclusions: On the whole, SPHYNX has passed the verification tests described below. For identical particle setting and initial
SEURAT: SPH scheme extended with ultraviolet line radiative transfer
Abe, Makito; Suzuki, Hiroyuki; Hasegawa, Kenji; Semelin, Benoit; Yajima, Hidenobu; Umemura, Masayuki
2018-05-01
We present a novel Lyman alpha (Ly α) radiative transfer code, SEURAT (SPH scheme Extended with Ultraviolet line RAdiative Transfer), where line scatterings are solved adaptively with the resolution of the smoothed particle hydrodynamics (SPH). The radiative transfer method implemented in SEURAT is based on a Monte Carlo algorithm in which the scattering and absorption by dust are also incorporated. We perform standard test calculations to verify the validity of the code; (i) emergent spectra from a static uniform sphere, (ii) emergent spectra from an expanding uniform sphere, and (iii) escape fraction from a dusty slab. Thereby, we demonstrate that our code solves the {Ly} α radiative transfer with sufficient accuracy. We emphasize that SEURAT can treat the transfer of {Ly} α photons even in highly complex systems that have significantly inhomogeneous density fields. The high adaptivity of SEURAT is desirable to solve the propagation of {Ly} α photons in the interstellar medium of young star-forming galaxies like {Ly} α emitters (LAEs). Thus, SEURAT provides a powerful tool to model the emergent spectra of {Ly} α emission, which can be compared to the observations of LAEs.
Energy Technology Data Exchange (ETDEWEB)
Yu, Y. Q. [Argonne National Lab. (ANL), Argonne, IL (United States); Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Mahadevan, Vijay S. [Argonne National Lab. (ANL), Argonne, IL (United States); Rahaman, Ronald O. [Argonne National Lab. (ANL), Argonne, IL (United States)
2016-02-29
SHARP, developed under the NEAMS Reactor Product Line, is an advanced modeling and simulation toolkit for the analysis of advanced nuclear reactors. SHARP is comprised of three physics modules currently including neutronics, thermal hydraulics, and structural mechanics. SHARP empowers designers to produce accurate results for modeling physical phenomena that have been identified as important for nuclear reactor analysis. SHARP can use existing physics codes and take advantage of existing infrastructure capabilities in the MOAB framework and the coupling driver/solver library, the Coupled Physics Environment (CouPE), which utilizes the widely used, scalable PETSc library. This report aims at identifying the coupled-physics simulation capability of SHARP by introducing the demonstration example called sahex in advance of the SHARP release expected by Mar 2016. sahex consists of 6 fuel pins with cladding, 1 control rod, sodium coolant and an outer duct wall that encloses all the other components. This example is carefully chosen to demonstrate the proof of concept for solving more complex demonstration examples such as EBR II assembly and ABTR full core. The workflow of preparing the input files, running the case and analyzing the results is demonstrated in this report. Moreover, an extension of the sahex model called sahex_core, which adds six homogenized neighboring assemblies to the full heterogeneous sahex model, is presented to test homogenization capabilities in both Nek5000 and PROTEUS. Some primary information on the configuration and build aspects for the SHARP toolkit, which includes capability to auto-download dependencies and configure/install with optimal flags in an architecture-aware fashion, is also covered by this report. A step-by-step instruction is provided to help users to create their cases. Details on these processes will be provided in the SHARP user manual that will accompany the first release.
International Nuclear Information System (INIS)
Yu, Y. Q.; Shemon, E. R.; Mahadevan, Vijay S.; Rahaman, Ronald O.
2016-01-01
SHARP, developed under the NEAMS Reactor Product Line, is an advanced modeling and simulation toolkit for the analysis of advanced nuclear reactors. SHARP is comprised of three physics modules currently including neutronics, thermal hydraulics, and structural mechanics. SHARP empowers designers to produce accurate results for modeling physical phenomena that have been identified as important for nuclear reactor analysis. SHARP can use existing physics codes and take advantage of existing infrastructure capabilities in the MOAB framework and the coupling driver/solver library, the Coupled Physics Environment (CouPE), which utilizes the widely used, scalable PETSc library. This report aims at identifying the coupled-physics simulation capability of SHARP by introducing the demonstration example called sahex in advance of the SHARP release expected by Mar 2016. sahex consists of 6 fuel pins with cladding, 1 control rod, sodium coolant and an outer duct wall that encloses all the other components. This example is carefully chosen to demonstrate the proof of concept for solving more complex demonstration examples such as EBR II assembly and ABTR full core. The workflow of preparing the input files, running the case and analyzing the results is demonstrated in this report. Moreover, an extension of the sahex model called sahex c ore, which adds six homogenized neighboring assemblies to the full heterogeneous sahex model, is presented to test homogenization capabilities in both Nek5000 and PROTEUS. Some primary information on the configuration and build aspects for the SHARP toolkit, which includes capability to auto-download dependencies and configure/install with optimal flags in an architecture-aware fashion, is also covered by this report. A step-by-step instruction is provided to help users to create their cases. Details on these processes will be provided in the SHARP user manual that will accompany the first release.
Quench Simulation of Superconducting Magnets with Commercial Multiphysics Software
AUTHOR|(SzGeCERN)751171; Auchmann, Bernhard; Jarkko, Niiranen; Maciejewski, Michal
The simulation of quenches in superconducting magnets is a multiphysics problem of highest complexity. Operated at 1.9 K above absolute zero, the material properties of superconductors and superfluid helium vary by several orders of magnitude over a range of only 10 K. The heat transfer from metal to helium goes through different transfer and boiling regimes as a function of temperature, heat flux, and transferred energy. Electrical, magnetic, thermal, and fluid dynamic effects are intimately coupled, yet live on vastly different time and spatial scales. While the physical models may be the same in all cases, it is an open debate whether the user should opt for commercial multiphysics software like ANSYS or COMSOL, write customized models based on general purpose network solvers like SPICE, or implement the physics models and numerical solvers entirely in custom software like the QP3, THEA, and ROXIE codes currently in use at the European Organisation for Nuclear Research (CERN). Each approach has its strengt...
Multiphysics modeling of magnetorheological dampers
Directory of Open Access Journals (Sweden)
D Case
2016-09-01
Full Text Available The dynamics of a small scale magnetorheological damper were modeled and analyzed using multiphysics commercial finite element software to couple the electromagnetic field distribution with the non-Newtonian fluid flow. The magnetic flux lines and field intensity generated within the damper and cyclic fluid flow in the damper under harmonic motion were simulated with the AC/DC and CFD physics modules of COMSOL Multiphysics, respectively. Coupling of the physics is achieved through a modified Bingham plastic definition, relating the fluid's dynamic viscosity to the intensity of the induced magnetic field. Good agreement is confirmed between simulation results and experimentally observed resistance forces in the damper. This study was conducted to determine the feasibility of utilizing magnetorheological dampers in a medical orthosis for pathological tremor attenuation. The implemented models are thus dimensioned on a relatively small scale. The method used, however, is not specific to the damper's size or geometry and can be extended to larger-scale devices with little or no complication.
Review of multi-physics temporal coupling methods for analysis of nuclear reactors
International Nuclear Information System (INIS)
Zerkak, Omar; Kozlowski, Tomasz; Gajev, Ivan
2015-01-01
Highlights: • Review of the numerical methods used for the multi-physics temporal coupling. • Review of high-order improvements to the Operator Splitting coupling method. • Analysis of truncation error due to the temporal coupling. • Recommendations on best-practice approaches for multi-physics temporal coupling. - Abstract: The advanced numerical simulation of a realistic physical system typically involves multi-physics problem. For example, analysis of a LWR core involves the intricate simulation of neutron production and transport, heat transfer throughout the structures of the system and the flowing, possibly two-phase, coolant. Such analysis involves the dynamic coupling of multiple simulation codes, each one devoted to the solving of one of the coupled physics. Multiple temporal coupling methods exist, yet the accuracy of such coupling is generally driven by the least accurate numerical scheme. The goal of this paper is to review in detail the approaches and numerical methods that can be used for the multi-physics temporal coupling, including a comprehensive discussion of the issues associated with the temporal coupling, and define approaches that can be used to perform multi-physics analysis. The paper is not limited to any particular multi-physics process or situation, but is intended to provide a generic description of multi-physics temporal coupling schemes for any development stage of the individual (single-physics) tools and methods. This includes a wide spectrum of situation, where the individual (single-physics) solvers are based on pre-existing computation codes embedded as individual components, or a new development where the temporal coupling can be developed and implemented as a part of code development. The discussed coupling methods are demonstrated in the framework of LWR core analysis
Coupled multi-physics simulation frameworks for reactor simulation: A bottom-up approach
International Nuclear Information System (INIS)
Tautges, Timothy J.; Caceres, Alvaro; Jain, Rajeev; Kim, Hong-Jun; Kraftcheck, Jason A.; Smith, Brandon M.
2011-01-01
A 'bottom-up' approach to multi-physics frameworks is described, where first common interfaces to simulation data are developed, then existing physics modules are adapted to communicate through those interfaces. Physics modules read and write data through those common interfaces, which also provide access to common simulation services like parallel IO, mesh partitioning, etc.. Multi-physics codes are assembled as a combination of physics modules, services, interface implementations, and driver code which coordinates calling these various pieces. Examples of various physics modules and services connected to this framework are given. (author)
Direct collapse to supermassive black hole seeds: comparing the AMR and SPH approaches.
Luo, Yang; Nagamine, Kentaro; Shlosman, Isaac
2016-07-01
We provide detailed comparison between the adaptive mesh refinement (AMR) code enzo-2.4 and the smoothed particle hydrodynamics (SPH)/ N -body code gadget-3 in the context of isolated or cosmological direct baryonic collapse within dark matter (DM) haloes to form supermassive black holes. Gas flow is examined by following evolution of basic parameters of accretion flows. Both codes show an overall agreement in the general features of the collapse; however, many subtle differences exist. For isolated models, the codes increase their spatial and mass resolutions at different pace, which leads to substantially earlier collapse in SPH than in AMR cases due to higher gravitational resolution in gadget-3. In cosmological runs, the AMR develops a slightly higher baryonic resolution than SPH during halo growth via cold accretion permeated by mergers. Still, both codes agree in the build-up of DM and baryonic structures. However, with the onset of collapse, this difference in mass and spatial resolution is amplified, so evolution of SPH models begins to lag behind. Such a delay can have effect on formation/destruction rate of H 2 due to UV background, and on basic properties of host haloes. Finally, isolated non-cosmological models in spinning haloes, with spin parameter λ ∼ 0.01-0.07, show delayed collapse for greater λ, but pace of this increase is faster for AMR. Within our simulation set-up, gadget-3 requires significantly larger computational resources than enzo-2.4 during collapse, and needs similar resources, during the pre-collapse, cosmological structure formation phase. Yet it benefits from substantially higher gravitational force and hydrodynamic resolutions, except at the end of collapse.
An implicit Smooth Particle Hydrodynamic code
Energy Technology Data Exchange (ETDEWEB)
Knapp, Charles E. [Univ. of New Mexico, Albuquerque, NM (United States)
2000-05-01
An implicit version of the Smooth Particle Hydrodynamic (SPH) code SPHINX has been written and is working. In conjunction with the SPHINX code the new implicit code models fluids and solids under a wide range of conditions. SPH codes are Lagrangian, meshless and use particles to model the fluids and solids. The implicit code makes use of the Krylov iterative techniques for solving large linear-systems and a Newton-Raphson method for non-linear corrections. It uses numerical derivatives to construct the Jacobian matrix. It uses sparse techniques to save on memory storage and to reduce the amount of computation. It is believed that this is the first implicit SPH code to use Newton-Krylov techniques, and is also the first implicit SPH code to model solids. A description of SPH and the techniques used in the implicit code are presented. Then, the results of a number of tests cases are discussed, which include a shock tube problem, a Rayleigh-Taylor problem, a breaking dam problem, and a single jet of gas problem. The results are shown to be in very good agreement with analytic solutions, experimental results, and the explicit SPHINX code. In the case of the single jet of gas case it has been demonstrated that the implicit code can do a problem in much shorter time than the explicit code. The problem was, however, very unphysical, but it does demonstrate the potential of the implicit code. It is a first step toward a useful implicit SPH code.
The Fluxgate Magnetometer Simulation in Comsol Multiphysics
Directory of Open Access Journals (Sweden)
Kolomeytsev Andrey
2018-01-01
Full Text Available This article describes the fluxgate magnetometer simulation in Comsol Multiphysics software package. The simulation results coincide with the experiment described earlier. Decomposition of the output signal by the Fourier coefficients shows a frequency doubling.
The Fluxgate Magnetometer Simulation in Comsol Multiphysics
Kolomeytsev Andrey; Baranov Pavel; Zatonov Ivan
2018-01-01
This article describes the fluxgate magnetometer simulation in Comsol Multiphysics software package. The simulation results coincide with the experiment described earlier. Decomposition of the output signal by the Fourier coefficients shows a frequency doubling.
Multiphysics simulation electromechanical system applications and optimization
Dede, Ercan M; Nomura, Tsuyoshi
2014-01-01
This book highlights a unique combination of numerical tools and strategies for handling the challenges of multiphysics simulation, with a specific focus on electromechanical systems as the target application. Features: introduces the concept of design via simulation, along with the role of multiphysics simulation in today's engineering environment; discusses the importance of structural optimization techniques in the design and development of electromechanical systems; provides an overview of the physics commonly involved with electromechanical systems for applications such as electronics, ma
Incompressible SPH (ISPH) with fast Poisson solver on a GPU
Chow, Alex D.; Rogers, Benedict D.; Lind, Steven J.; Stansby, Peter K.
2018-05-01
This paper presents a fast incompressible SPH (ISPH) solver implemented to run entirely on a graphics processing unit (GPU) capable of simulating several millions of particles in three dimensions on a single GPU. The ISPH algorithm is implemented by converting the highly optimised open-source weakly-compressible SPH (WCSPH) code DualSPHysics to run ISPH on the GPU, combining it with the open-source linear algebra library ViennaCL for fast solutions of the pressure Poisson equation (PPE). Several challenges are addressed with this research: constructing a PPE matrix every timestep on the GPU for moving particles, optimising the limited GPU memory, and exploiting fast matrix solvers. The ISPH pressure projection algorithm is implemented as 4 separate stages, each with a particle sweep, including an algorithm for the population of the PPE matrix suitable for the GPU, and mixed precision storage methods. An accurate and robust ISPH boundary condition ideal for parallel processing is also established by adapting an existing WCSPH boundary condition for ISPH. A variety of validation cases are presented: an impulsively started plate, incompressible flow around a moving square in a box, and dambreaks (2-D and 3-D) which demonstrate the accuracy, flexibility, and speed of the methodology. Fragmentation of the free surface is shown to influence the performance of matrix preconditioners and therefore the PPE matrix solution time. The Jacobi preconditioner demonstrates robustness and reliability in the presence of fragmented flows. For a dambreak simulation, GPU speed ups demonstrate up to 10-18 times and 1.1-4.5 times compared to single-threaded and 16-threaded CPU run times respectively.
Water Flow Simulation using Smoothed Particle Hydrodynamics (SPH)
Vu, Bruce; Berg, Jared; Harris, Michael F.
2014-01-01
Simulation of water flow from the rainbird nozzles has been accomplished using the Smoothed Particle Hydrodynamics (SPH). The advantage of using SPH is that no meshing is required, thus the grid quality is no longer an issue and accuracy can be improved.
A Comparison of Grid-based and SPH Binary Mass-transfer and Merger Simulations
Energy Technology Data Exchange (ETDEWEB)
Motl, Patrick M. [Indiana University Kokomo, School of Sciences, P.O. Box 9003, Kokomo, IN 46903-9004 (United States); Frank, Juhan; Clayton, Geoffrey C.; Tohline, Joel E. [Louisiana State University, Department of Physics and Astronomy, 202 Nicholson Hall, Baton Rouge, LA 70803-4001 (United States); Staff, Jan [College of Science and Math, University of Virgin Islands, St. Thomas, United States Virgin Islands 00802 (United States); Fryer, Christopher L.; Even, Wesley [Center for Theoretical Astrophysics/CCS-2, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Diehl, Steven, E-mail: pmotl@iuk.edu [TLT-Turbo GmbH, Gleiwitzstrasse 7, 66482 Zweibrücken (Germany)
2017-04-01
There is currently a great amount of interest in the outcomes and astrophysical implications of mergers of double degenerate binaries. In a commonly adopted approximation, the components of such binaries are represented by polytropes with an index of n = 3/2. We present detailed comparisons of stellar mass-transfer and merger simulations of polytropic binaries that have been carried out using two very different numerical algorithms—a finite-volume “grid” code and a smoothed-particle hydrodynamics (SPH) code. We find that there is agreement in both the ultimate outcomes of the evolutions and the intermediate stages if the initial conditions for each code are chosen to match as closely as possible. We find that even with closely matching initial setups, the time it takes to reach a concordant evolution differs between the two codes because the initial depth of contact cannot be matched exactly. There is a general tendency for SPH to yield higher mass transfer rates and faster evolution to the final outcome. We also present comparisons of simulations calculated from two different energy equations: in one series, we assume a polytropic equation of state and in the other series an ideal gas equation of state. In the latter series of simulations, an atmosphere forms around the accretor, which can exchange angular momentum and cause a more rapid loss of orbital angular momentum. In the simulations presented here, the effect of the ideal equation of state is to de-stabilize the binary in both SPH and grid simulations, but the effect is more pronounced in the grid code.
Multiscale and Multiphysics Modeling of Additive Manufacturing of Advanced Materials
Liou, Frank; Newkirk, Joseph; Fan, Zhiqiang; Sparks, Todd; Chen, Xueyang; Fletcher, Kenneth; Zhang, Jingwei; Zhang, Yunlu; Kumar, Kannan Suresh; Karnati, Sreekar
2015-01-01
, after investigating various methods, a Smoothed Particle Hydrodynamics Model (SPH Model) was developed to model wire feeding process. Its computational efficiency and simple architecture makes it more robust and flexible than other models. More research on material properties may be needed to realistically model the AAM processes. A microscale model was developed to investigate heterogeneous nucleation, dendritic grain growth, epitaxial growth of columnar grains, columnar-to-equiaxed transition, grain transport in melt, and other properties. The orientations of the columnar grains were almost perpendicular to the laser motion's direction. Compared to the similar studies in the literature, the multiple grain morphology modeling result is in the same order of magnitude as optical morphologies in the experiment. Experimental work was conducted to validate different models. An infrared camera was incorporated as a process monitoring and validating tool to identify the solidus and mushy zones during deposition. The images were successfully processed to identify these regions. This research project has investigated multiscale and multiphysics of the complex AAM processes thus leading to advanced understanding of these processes. The project has also developed several modeling tools and experimental validation tools that will be very critical in the future of AAM process qualification and certification.
Scalable Adaptive Multilevel Solvers for Multiphysics Problems
Energy Technology Data Exchange (ETDEWEB)
Xu, Jinchao [Pennsylvania State Univ., University Park, PA (United States). Dept. of Mathematics
2014-11-26
In this project, we carried out many studies on adaptive and parallel multilevel methods for numerical modeling for various applications, including Magnetohydrodynamics (MHD) and complex fluids. We have made significant efforts and advances in adaptive multilevel methods of the multiphysics problems: multigrid methods, adaptive finite element methods, and applications.
Specification of the Advanced Burner Test Reactor Multi-Physics Coupling Demonstration Problem
Energy Technology Data Exchange (ETDEWEB)
Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Grudzinski, J. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Lee, C. H. [Argonne National Lab. (ANL), Argonne, IL (United States); Thomas, J. W. [Argonne National Lab. (ANL), Argonne, IL (United States); Yu, Y. Q. [Argonne National Lab. (ANL), Argonne, IL (United States)
2015-12-21
This document specifies the multi-physics nuclear reactor demonstration problem using the SHARP software package developed by NEAMS. The SHARP toolset simulates the key coupled physics phenomena inside a nuclear reactor. The PROTEUS neutronics code models the neutron transport within the system, the Nek5000 computational fluid dynamics code models the fluid flow and heat transfer, and the DIABLO structural mechanics code models structural and mechanical deformation. The three codes are coupled to the MOAB mesh framework which allows feedback from neutronics, fluid mechanics, and mechanical deformation in a compatible format.
Tensile Instability and Artificial Stresses in Impact Problems in SPH
International Nuclear Information System (INIS)
Mehra, Vishal; Sijoy C D; Mishra, Vinayak; Chaturvedi, Shashank
2012-01-01
The smooth particle hydrodynamics (SPH) is a meshless computational technique that is popular in the modeling of impact and penetration problems. However, SPH is liable to a tensile instability that manifests itself as a bunching of nodes and formation of artificial voids and no generally accepted formulation exists to counter this instability. We examine the performance of two methods that have been proposed to deal with the tensile instability— the Monaghan artificial stresses and the Godunov-type SPH. The impact and penetration of 0.5 cm radii steel spheres on 2 mm thick aluminium plate at 3.1 km/s is chosen for comparison. We show that the artificial void formation in St-Al impact is suppressed but not eliminated by using Monaghan stresses while the void formation is entirely eliminated by using Godunov-type formulation of SPH that was proposed by Parshikov and Medin.
Multiphysical Testing of Soils and Shales
Ferrari, Alessio
2013-01-01
Significant advancements in the experimental analysis of soils and shales have been achieved during the last few decades. Outstanding progress in the field has led to the theoretical development of geomechanical theories and important engineering applications. This book provides the reader with an overview of recent advances in a variety of advanced experimental techniques and results for the analysis of the behaviour of geomaterials under multiphysical testing conditions. Modern trends in experimental geomechanics for soils and shales are discussed, including testing materials in variably saturated conditions, non-isothermal experiments, micro-scale investigations and image analysis techniques. Six theme papers from leading researchers in experimental geomechanics are also included. This book is intended for postgraduate students, researchers and practitioners in fields where multiphysical testing of soils and shales plays a fundamental role, such as unsaturated soil and rock mechanics, petroleum engineering...
Massive hybrid parallelism for fully implicit multiphysics
International Nuclear Information System (INIS)
Gaston, D. R.; Permann, C. J.; Andrs, D.; Peterson, J. W.
2013-01-01
As hardware advances continue to modify the supercomputing landscape, traditional scientific software development practices will become more outdated, ineffective, and inefficient. The process of rewriting/retooling existing software for new architectures is a Sisyphean task, and results in substantial hours of development time, effort, and money. Software libraries which provide an abstraction of the resources provided by such architectures are therefore essential if the computational engineering and science communities are to continue to flourish in this modern computing environment. The Multiphysics Object Oriented Simulation Environment (MOOSE) framework enables complex multiphysics analysis tools to be built rapidly by scientists, engineers, and domain specialists, while also allowing them to both take advantage of current HPC architectures, and efficiently prepare for future supercomputer designs. MOOSE employs a hybrid shared-memory and distributed-memory parallel model and provides a complete and consistent interface for creating multiphysics analysis tools. In this paper, a brief discussion of the mathematical algorithms underlying the framework and the internal object-oriented hybrid parallel design are given. Representative massively parallel results from several applications areas are presented, and a brief discussion of future areas of research for the framework are provided. (authors)
Massive hybrid parallelism for fully implicit multiphysics
Energy Technology Data Exchange (ETDEWEB)
Gaston, D. R.; Permann, C. J.; Andrs, D.; Peterson, J. W. [Idaho National Laboratory, 2525 N. Fremont Ave., Idaho Falls, ID 83415 (United States)
2013-07-01
As hardware advances continue to modify the supercomputing landscape, traditional scientific software development practices will become more outdated, ineffective, and inefficient. The process of rewriting/retooling existing software for new architectures is a Sisyphean task, and results in substantial hours of development time, effort, and money. Software libraries which provide an abstraction of the resources provided by such architectures are therefore essential if the computational engineering and science communities are to continue to flourish in this modern computing environment. The Multiphysics Object Oriented Simulation Environment (MOOSE) framework enables complex multiphysics analysis tools to be built rapidly by scientists, engineers, and domain specialists, while also allowing them to both take advantage of current HPC architectures, and efficiently prepare for future supercomputer designs. MOOSE employs a hybrid shared-memory and distributed-memory parallel model and provides a complete and consistent interface for creating multiphysics analysis tools. In this paper, a brief discussion of the mathematical algorithms underlying the framework and the internal object-oriented hybrid parallel design are given. Representative massively parallel results from several applications areas are presented, and a brief discussion of future areas of research for the framework are provided. (authors)
MASSIVE HYBRID PARALLELISM FOR FULLY IMPLICIT MULTIPHYSICS
Energy Technology Data Exchange (ETDEWEB)
Cody J. Permann; David Andrs; John W. Peterson; Derek R. Gaston
2013-05-01
As hardware advances continue to modify the supercomputing landscape, traditional scientific software development practices will become more outdated, ineffective, and inefficient. The process of rewriting/retooling existing software for new architectures is a Sisyphean task, and results in substantial hours of development time, effort, and money. Software libraries which provide an abstraction of the resources provided by such architectures are therefore essential if the computational engineering and science communities are to continue to flourish in this modern computing environment. The Multiphysics Object Oriented Simulation Environment (MOOSE) framework enables complex multiphysics analysis tools to be built rapidly by scientists, engineers, and domain specialists, while also allowing them to both take advantage of current HPC architectures, and efficiently prepare for future supercomputer designs. MOOSE employs a hybrid shared-memory and distributed-memory parallel model and provides a complete and consistent interface for creating multiphysics analysis tools. In this paper, a brief discussion of the mathematical algorithms underlying the framework and the internal object-oriented hybrid parallel design are given. Representative massively parallel results from several applications areas are presented, and a brief discussion of future areas of research for the framework are provided.
Multiphysical Simulation of PT-CT Contact with Outer Boundary Condition
Energy Technology Data Exchange (ETDEWEB)
Chang, Se-Myong [Kunsan National Univ., Gunsan (Korea, Republic of); Kim, Hyoung Tae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2016-10-15
The present study is about preliminary calculation results for these ICSP activity works, where the COMSOL Multiphysics code is used to simulate plastic deformation of a pressure tube as a result of the interaction of stress and temperature. It is shown that the thermal stress model of COMSOL is compatible to simulate the multiple heat transfers (including the radiation heat transfer and heat conduction) and stress strain in the simplified 2-D problem. The benchmark test result for radiation heat transfer is in good agreement with the analytical solution for the concentric configuration of PT(pressure tube) and CT(calandria tube). In this paper, the authors did an open computation of these multi-physical phenomena by changing the outer boundary condition of CT according to the experimental result of ICSP. A series of simulation has been done based on the benchmark test proposed by IAEA/ICSP. The unsteady multi-physics was treated some numerical models with COMSOL. The comparison with CATHENA code is verified as a good agreement as we increase the accuracy of numerical method, Gaussian quadrature. The open computation for the validation of this numerical code is still on-going, and the temperature inside and outside the PT shows a very good agreement.
Multiphysical Simulation of PT-CT Contact with Outer Boundary Condition
International Nuclear Information System (INIS)
Chang, Se-Myong; Kim, Hyoung Tae
2016-01-01
The present study is about preliminary calculation results for these ICSP activity works, where the COMSOL Multiphysics code is used to simulate plastic deformation of a pressure tube as a result of the interaction of stress and temperature. It is shown that the thermal stress model of COMSOL is compatible to simulate the multiple heat transfers (including the radiation heat transfer and heat conduction) and stress strain in the simplified 2-D problem. The benchmark test result for radiation heat transfer is in good agreement with the analytical solution for the concentric configuration of PT(pressure tube) and CT(calandria tube). In this paper, the authors did an open computation of these multi-physical phenomena by changing the outer boundary condition of CT according to the experimental result of ICSP. A series of simulation has been done based on the benchmark test proposed by IAEA/ICSP. The unsteady multi-physics was treated some numerical models with COMSOL. The comparison with CATHENA code is verified as a good agreement as we increase the accuracy of numerical method, Gaussian quadrature. The open computation for the validation of this numerical code is still on-going, and the temperature inside and outside the PT shows a very good agreement
Integration of Advanced Probabilistic Analysis Techniques with Multi-Physics Models
Energy Technology Data Exchange (ETDEWEB)
Cetiner, Mustafa Sacit; none,; Flanagan, George F. [ORNL; Poore III, Willis P. [ORNL; Muhlheim, Michael David [ORNL
2014-07-30
An integrated simulation platform that couples probabilistic analysis-based tools with model-based simulation tools can provide valuable insights for reactive and proactive responses to plant operating conditions. The objective of this work is to demonstrate the benefits of a partial implementation of the Small Modular Reactor (SMR) Probabilistic Risk Assessment (PRA) Detailed Framework Specification through the coupling of advanced PRA capabilities and accurate multi-physics plant models. Coupling a probabilistic model with a multi-physics model will aid in design, operations, and safety by providing a more accurate understanding of plant behavior. This represents the first attempt at actually integrating these two types of analyses for a control system used for operations, on a faster than real-time basis. This report documents the development of the basic communication capability to exchange data with the probabilistic model using Reliability Workbench (RWB) and the multi-physics model using Dymola. The communication pathways from injecting a fault (i.e., failing a component) to the probabilistic and multi-physics models were successfully completed. This first version was tested with prototypic models represented in both RWB and Modelica. First, a simple event tree/fault tree (ET/FT) model was created to develop the software code to implement the communication capabilities between the dynamic-link library (dll) and RWB. A program, written in C#, successfully communicates faults to the probabilistic model through the dll. A systems model of the Advanced Liquid-Metal Reactor–Power Reactor Inherently Safe Module (ALMR-PRISM) design developed under another DOE project was upgraded using Dymola to include proper interfaces to allow data exchange with the control application (ConApp). A program, written in C+, successfully communicates faults to the multi-physics model. The results of the example simulation were successfully plotted.
Comparing AMR and SPH Cosmological Simulations. I. Dark Matter and Adiabatic Simulations
O'Shea, Brian W.; Nagamine, Kentaro; Springel, Volker; Hernquist, Lars; Norman, Michael L.
2005-09-01
We compare two cosmological hydrodynamic simulation codes in the context of hierarchical galaxy formation: the Lagrangian smoothed particle hydrodynamics (SPH) code GADGET, and the Eulerian adaptive mesh refinement (AMR) code Enzo. Both codes represent dark matter with the N-body method but use different gravity solvers and fundamentally different approaches for baryonic hydrodynamics. The SPH method in GADGET uses a recently developed ``entropy conserving'' formulation of SPH, while for the mesh-based Enzo two different formulations of Eulerian hydrodynamics are employed: the piecewise parabolic method (PPM) extended with a dual energy formulation for cosmology, and the artificial viscosity-based scheme used in the magnetohydrodynamics code ZEUS. In this paper we focus on a comparison of cosmological simulations that follow either only dark matter, or also a nonradiative (``adiabatic'') hydrodynamic gaseous component. We perform multiple simulations using both codes with varying spatial and mass resolution with identical initial conditions. The dark matter-only runs agree generally quite well provided Enzo is run with a comparatively fine root grid and a low overdensity threshold for mesh refinement, otherwise the abundance of low-mass halos is suppressed. This can be readily understood as a consequence of the hierarchical particle-mesh algorithm used by Enzo to compute gravitational forces, which tends to deliver lower force resolution than the tree-algorithm of GADGET at early times before any adaptive mesh refinement takes place. At comparable force resolution we find that the latter offers substantially better performance and lower memory consumption than the present gravity solver in Enzo. In simulations that include adiabatic gasdynamics we find general agreement in the distribution functions of temperature, entropy, and density for gas of moderate to high overdensity, as found inside dark matter halos. However, there are also some significant differences in
Advanced multi-physics simulation capability for very high temperature reactors
International Nuclear Information System (INIS)
Lee, Hyun Chul; Tak, Nam Il; Jo Chang Keun; Noh, Jae Man; Cho, Bong Hyun; Cho, Jin Woung; Hong, Ser Gi
2012-01-01
The purpose of this research is to develop methodologies and computer code for high-fidelity multi-physics analysis of very high temperature gas-cooled reactors(VHTRs). The research project was performed through Korea-US I-NERI program. The main research topic was development of methodologies for high-fidelity 3-D whole core transport calculation, development of DeCART code for VHTR reactor physics analysis, generation of VHTR specific 190-group cross-section library for DeCART code, development of DeCART/CORONA coupled code system for neutronics/thermo-fluid multi-physics analysis, and benchmark analysis against various benchmark problems derived from PMR200 reactor. The methodologies and the code systems will be utilized a key technologies in the Nuclear Hydrogen Development and Demonstration program. Export of code system is expected in the near future and the code systems developed in this project are expected to contribute to development and export of nuclear hydrogen production system
Reactive transport modeling of the ABM experiment with Comsol Multiphysics
International Nuclear Information System (INIS)
Pekala, Marek; Idiart, Andres; Arcos, David
2012-01-01
Document available in extended abstract form only. The Swedish Organisation for Radioactive Waste Disposal (SKB) is considering disposal of the High Level Waste in a deep underground repository in a crystalline rock. According to the disposal concept, bentonite clay will be used in the near-field of the waste packages as buffer material. From solute transport point of view, the bentonite buffer is expected to provide a favourable environment, where radionuclide migration would be limited to slow diffusion and further retarded by sorption. In the KBS-3 repository design, the MX-80 bentonite is the reference buffer material. However, SKB has also been investigating alternative buffer materials. To this end, the field experiment Alternative Buffer Materials (ABM) was started at the Aespoe URL in 2006. Three packages of eleven different compacted bentonite blocks in different configurations have been tested over varying time scales. The packages with outer diameter of 0.28 m were deposited into 3 meter deep boreholes. After installation, packages were saturated and heated differently to target values. This contribution concerns the evolution of Package 1, which was initiated in December 2006 and ran for about 2.5 years. Post-mortem examination after retrieval showed that the initially contrasting chloride concentrations and cation-exchanger compositions between different bentonite blocks became significantly homogenised. It is thought that this behaviour could be explained as a first approximation by diffusion of major ions between the bentonite blocks coupled with cation-exchange. In this work, a modelling study to verify this hypothesis has been undertaken. In addition, the feasibility of implementing a reactive transport model into the Finite Element code COMSOL Multiphysics has been tested. The model considers a two-dimensional axisymmetric geometry of the depositional borehole, and includes coupled diffusion and cation-exchange of Na, K, Ca and Mg (as a chloride
Fourtakas, G.; Rogers, B. D.
2016-06-01
A two-phase numerical model using Smoothed Particle Hydrodynamics (SPH) is applied to two-phase liquid-sediments flows. The absence of a mesh in SPH is ideal for interfacial and highly non-linear flows with changing fragmentation of the interface, mixing and resuspension. The rheology of sediment induced under rapid flows undergoes several states which are only partially described by previous research in SPH. This paper attempts to bridge the gap between the geotechnics, non-Newtonian and Newtonian flows by proposing a model that combines the yielding, shear and suspension layer which are needed to predict accurately the global erosion phenomena, from a hydrodynamics prospective. The numerical SPH scheme is based on the explicit treatment of both phases using Newtonian and the non-Newtonian Bingham-type Herschel-Bulkley-Papanastasiou constitutive model. This is supplemented by the Drucker-Prager yield criterion to predict the onset of yielding of the sediment surface and a concentration suspension model. The multi-phase model has been compared with experimental and 2-D reference numerical models for scour following a dry-bed dam break yielding satisfactory results and improvements over well-known SPH multi-phase models. With 3-D simulations requiring a large number of particles, the code is accelerated with a graphics processing unit (GPU) in the open-source DualSPHysics code. The implementation and optimisation of the code achieved a speed up of x58 over an optimised single thread serial code. A 3-D dam break over a non-cohesive erodible bed simulation with over 4 million particles yields close agreement with experimental scour and water surface profiles.
Multiphysics Model Development and the Core Analysis for In Situ Breeding and Burning Reactor
Directory of Open Access Journals (Sweden)
Shengyi Si
2013-01-01
Full Text Available The in situ breeding and burning reactor (ISBBR, which makes use of the outstanding breeding capability of metallic pellet and the excellent irradiation-resistant performance of SiCf/SiC ceramic composites cladding, can approach the design purpose of ultralong cycle and ultrahigh burnup and maintain stable radial power distribution during the cycle life without refueling and shuffling. Since the characteristics of the fuel pellet and cladding are different from the traditional fuel rod of ceramic pellet and metallic cladding, the multiphysics behaviors in ISBBR are also quite different. A computer code, named TANG, to model the specific multiphysics behaviors in ISBBR has been developed. The primary calculation results provided by TANG demonstrate that ISBBR has an excellent comprehensive performance of GEN-IV and a great development potential.
Multiphysics modeling of a rail gun launcher
Directory of Open Access Journals (Sweden)
Y W Kwon
2016-03-01
Full Text Available A finite element based multiphysics modeling was conducted for a rail gunlauncher to predict the exit velocity of the launch object, and temperaturedistribution. For this modeling, electromagnetic field analysis, heat transferanalysis, thermal stress analysis, and dynamic analysis were conducted fora system consisting of two parallel rails and a moving armature. In particular,an emphasis was given to model the contact interface between rails andthe armature. A contact theory was used to estimate the electric as well asthermal conductivities at the interface. Using the developed model, aparametric study was conducted to understand effects of variousparameters on the exit velocity as well as the temperature distribution in therail gun launcher.
A Multi-Physics simulation of the Reactor Core using CUPID/MASTER
International Nuclear Information System (INIS)
Lee, Jae Ryong; Cho, Hyoung Kyu; Yoon, Han Young; Cho, Jin Young; Jeong, Jae Jun
2011-01-01
KAERI has been developing a component-scale thermal hydraulics code, CUPID. The aim of the code is for multi-dimensional, multi-physics and multi-scale thermal hydraulics analysis. In our previous papers, the CUPID code has proved to be able to reproduce multidimensional thermal hydraulic analysis by validated with various conceptual problems and experimental data. For the numerical closure, it adopts a three dimensional, transient, two-phase and three-field model, and includes physical models and correlations of the interfacial mass, momentum, and energy transfer. For the multi-scale analysis, the CUPID is on progress to merge into system-scale thermal hydraulic code, MARS. In the present paper, a multi-physics simulation was performed by coupling the CUPID with three dimensional neutron kinetics code, MASTER. The MASTER is merged into the CUPID as a dynamic link library (DLL). The APR1400 reactor core during control rod drop/ejection accident was simulated as an example by adopting a porous media approach to employ fuel assembly. The following sections present the numerical modeling for the reactor core, coupling of the kinetics code, and the simulation results
CANDU fuel bundle deformation modelling with COMSOL multiphysics
International Nuclear Information System (INIS)
Bell, J.S.; Lewis, B.J.
2012-01-01
Highlights: ► The deformation behaviour of a CANDU fuel bundle was modelled. ► The model has been developed on a commercial finite-element platform. ► Pellet/sheath interaction and end-plate restraint effects were considered. ► The model was benchmarked against the BOW code and a variable-load experiment. - Abstract: A model to describe deformation behaviour of a CANDU 37-element bundle has been developed under the COMSOL Multiphysics finite-element platform. Beam elements were applied to the fuel elements (composed of fuel sheaths and pellets) and endplates in order to calculate the bowing behaviour of the fuel elements. This model is important to help assess bundle-deformation phenomena, which may lead to more restrictive coolant flow through the sub-channels of the horizontally oriented bundle. The bundle model was compared to the BOW code for the occurrence of a dry-out patch, and benchmarked against an out-reactor experiment with a variable load on an outer fuel element.
Adaptive hybrid mesh refinement for multiphysics applications
International Nuclear Information System (INIS)
Khamayseh, Ahmed; Almeida, Valmor de
2007-01-01
The accuracy and convergence of computational solutions of mesh-based methods is strongly dependent on the quality of the mesh used. We have developed methods for optimizing meshes that are comprised of elements of arbitrary polygonal and polyhedral type. We present in this research the development of r-h hybrid adaptive meshing technology tailored to application areas relevant to multi-physics modeling and simulation. Solution-based adaptation methods are used to reposition mesh nodes (r-adaptation) or to refine the mesh cells (h-adaptation) to minimize solution error. The numerical methods perform either the r-adaptive mesh optimization or the h-adaptive mesh refinement method on the initial isotropic or anisotropic meshes to equidistribute weighted geometric and/or solution error function. We have successfully introduced r-h adaptivity to a least-squares method with spherical harmonics basis functions for the solution of the spherical shallow atmosphere model used in climate modeling. In addition, application of this technology also covers a wide range of disciplines in computational sciences, most notably, time-dependent multi-physics, multi-scale modeling and simulation
SPH for impact force and ricochet behavior of water-entry bodies
Omidvar, Pourya; Farghadani, Omid; Nikeghbali, Pooyan
The numerical modeling of fluid interaction with a bouncing body has many applications in scientific and engineering application. In this paper, the problem of water impact of a body on free-surface is investigated, where the fixed ghost boundary condition is added to the open source code SPHysics2D1 to rectify the oscillations in pressure distributions with the repulsive boundary condition. First, after introducing the methodology of SPH and the option of boundary conditions, the still water problem is simulated using two types of boundary conditions. It is shown that the fixed ghost boundary condition gives a better result for a hydrostatics pressure. Then, the dam-break problem, which is a bench mark test case in SPH, is simulated and compared with available data. In order to show the behavior of the hydrostatics forces on bodies, a fix/floating cylinder is placed on free surface looking carefully at the force and heaving profile. Finally, the impact of a body on free-surface is successfully simulated for different impact angles and velocities.
Rapid filling of pipelines with the SPH particle method
Hou, Q.; Zhang, L.X.; Tijsseling, A.S.; Kruisbrink, A.C.H.
2011-01-01
The paper reports the development and application of a SPH (smoothed particle hydrodynamics) based simulation of rapid filling of pipelines, for which the rigid-column model is commonly used. In this paper the water-hammer equations with a moving boundary are used to model the pipe filling process,
Rapid filling of pipelines with the SPH particle method
Hou, Q.; Zhang, L.X.; Tijsseling, A.S.; Kruisbrink, A.C.H.
2012-01-01
The paper reports the development and application of a SPH (smoothed particle hydrodynamics) based simulation of rapid filling of pipelines, for which the rigid-column model is commonly used. In this paper the water-hammer equations with a moving boundary are used to model the pipe filling process,
Grain sedimentation with SPH-DEM and its validation
Robinson, M.J.; Luding, Stefan; Ramaioli, Marco; Yu, A; Dong, K; Yang, R; Luding, S
2013-01-01
Our mesoscale simulation method [M. Robinson, S. Luding, and M. Ramaioli, submitted (2013)] for multiphase fluid-particle flows couples Smoothed Particle Hydrodynamics (SPH) and the Discrete Element Method (DEM) and enjoys the flexibility of meshless methods, such as being capable to handling free
An Improved SPH Technique for Fracture Modeling
National Research Council Canada - National Science Library
Libersky, Larry
2000-01-01
.... With these improvements, the MAGI code could solve the enormously complex problem of simulating Behind-Armor-Debris and subsequent interaction of the spall cloud with threat target components as well...
Meshless Lagrangian SPH method applied to isothermal lid-driven cavity flow at low-Re numbers
Fraga Filho, C. A. D.; Chacaltana, J. T. A.; Pinto, W. J. N.
2018-01-01
SPH is a recent particle method applied in the cavities study, without many results available in the literature. The lid-driven cavity flow is a classic problem of the fluid mechanics, extensively explored in the literature and presenting a considerable complexity. The aim of this paper is to present a solution from the Lagrangian viewpoint for this problem. The discretization of the continuum domain is performed using the Lagrangian particles. The physical laws of mass, momentum and energy conservation are presented by the Navier-Stokes equations. A serial numerical code, written in Fortran programming language, has been used to perform the numerical simulations. The application of the SPH and comparison with the literature (mesh methods and a meshless collocation method) have been done. The positions of the primary vortex centre and the non-dimensional velocity profiles passing through the geometric centre of the cavity have been analysed. The numerical Lagrangian results showed a good agreement when compared to the results found in the literature, specifically for { Re} < 100.00 . Suggestions for improvements in the SPH model presented are listed, in the search for better results for flows with higher Reynolds numbers.
International Nuclear Information System (INIS)
Ivanov, K.; Avramova, M.
2007-01-01
Current trends in nuclear power generation and regulation as well as the design of next generation reactor concepts along with the continuing computer technology progress stimulate the development, qualification and application of multi-physics multi-scale coupled code systems. The efforts have been focused on extending the analysis capabilities by coupling models, which simulate different phenomena or system components, as well as on refining the scale and level of detail of the coupling. This paper reviews the progress made in this area and outlines the remaining challenges. The discussion is illustrated with examples based on neutronics/thermohydraulics coupling in the reactor core modeling. In both fields recent advances and developments are towards more physics-based high-fidelity simulations, which require implementation of improved and flexible coupling methodologies. First, the progresses in coupling of different physics codes along with the advances in multi-level techniques for coupled code simulations are discussed. Second, the issues related to the consistent qualification of coupled multi-physics and multi-scale code systems for design and safety evaluation are presented. The increased importance of uncertainty and sensitivity analysis are discussed along with approaches to propagate the uncertainty quantification between the codes. The incoming OECD LWR Uncertainty Analysis in Modeling (UAM) benchmark is the first international activity to address this issue and it is described in the paper. Finally, the remaining challenges with multi-physics coupling are outlined. (authors)
Energy Technology Data Exchange (ETDEWEB)
Ivanov, K.; Avramova, M. [Pennsylvania State Univ., University Park, PA (United States)
2007-07-01
Current trends in nuclear power generation and regulation as well as the design of next generation reactor concepts along with the continuing computer technology progress stimulate the development, qualification and application of multi-physics multi-scale coupled code systems. The efforts have been focused on extending the analysis capabilities by coupling models, which simulate different phenomena or system components, as well as on refining the scale and level of detail of the coupling. This paper reviews the progress made in this area and outlines the remaining challenges. The discussion is illustrated with examples based on neutronics/thermohydraulics coupling in the reactor core modeling. In both fields recent advances and developments are towards more physics-based high-fidelity simulations, which require implementation of improved and flexible coupling methodologies. First, the progresses in coupling of different physics codes along with the advances in multi-level techniques for coupled code simulations are discussed. Second, the issues related to the consistent qualification of coupled multi-physics and multi-scale code systems for design and safety evaluation are presented. The increased importance of uncertainty and sensitivity analysis are discussed along with approaches to propagate the uncertainty quantification between the codes. The incoming OECD LWR Uncertainty Analysis in Modeling (UAM) benchmark is the first international activity to address this issue and it is described in the paper. Finally, the remaining challenges with multi-physics coupling are outlined. (authors)
The application of a multi-physics tool kit to spatial reactor dynamics
International Nuclear Information System (INIS)
Clifford, I.; Jasak, H.
2009-01-01
Traditionally coupled field nuclear reactor analysis has been carried out using several loosely coupled solvers, each having been developed independently from the others. In the field of multi-physics, the current generation of object-oriented tool kits provides robust close coupling of multiple fields on a single framework. This paper describes the initial results obtained as part of continuing research in the use of the OpenFOAM multi-physics tool kit for reactor dynamics application development. An unstructured, three-dimensional, time-dependent multi-group diffusion code Diffusion FOAM has been developed using the OpenFOAM multi-physics tool kit as a basis. The code is based on the finite-volume methodology and uses a newly developed block-coupled sparse matrix solver for the coupled solution of the multi-group diffusion equations. A description of this code is given with particular emphasis on the newly developed block-coupled solver, along with a selection of results obtained thus far. The code has performed well, indicating that the OpenFOAM tool kit is suited to reactor dynamics applications. This work has shown that the neutronics and simplified thermal-hydraulics of a reactor May be represented and solved for using a common calculation platform, and opens up the possibility for research into robust close-coupling of neutron diffusion and thermal-fluid calculations. This work has further opened up the possibility for research in a number of other areas, including research into three-dimensional unstructured meshes for reactor dynamics applications. (authors)
Multiphysics modelling of manufacturing processes: A review
DEFF Research Database (Denmark)
Jabbari, Masoud; Baran, Ismet; Mohanty, Sankhya
2018-01-01
Numerical modelling is increasingly supporting the analysis and optimization of manufacturing processes in the production industry. Even if being mostly applied to multistep processes, single process steps may be so complex by nature that the needed models to describe them must include multiphysics...... the diversity in the field of modelling of manufacturing processes as regards process, materials, generic disciplines as well as length scales: (1) modelling of tape casting for thin ceramic layers, (2) modelling the flow of polymers in extrusion, (3) modelling the deformation process of flexible stamps...... for nanoimprint lithography, (4) modelling manufacturing of composite parts and (5) modelling the selective laser melting process. For all five examples, the emphasis is on modelling results as well as describing the models in brief mathematical details. Alongside with relevant references to the original work...
Multiphysics modelling of the spray forming process
International Nuclear Information System (INIS)
Mi, J.; Grant, P.S.; Fritsching, U.; Belkessam, O.; Garmendia, I.; Landaberea, A.
2008-01-01
An integrated, multiphysics numerical model has been developed through the joint efforts of the University of Oxford (UK), University of Bremen (Germany) and Inasmet (Spain) to simulate the spray forming process. The integrated model consisted of four sub-models: (1) an atomization model simulating the fragmentation of a continuous liquid metal stream into droplet spray during gas atomization; (2) a droplet spray model simulating the droplet spray mass and enthalpy evolution in the gas flow field prior to deposition; (3) a droplet deposition model simulating droplet deposition, splashing and re-deposition behavior and the resulting preform shape and heat flow; and (4) a porosity model simulating the porosity distribution inside a spray formed ring preform. The model has been validated against experiments of the spray forming of large diameter IN718 Ni superalloy rings. The modelled preform shape, surface temperature and final porosity distribution showed good agreement with experimental measurements
A high-order SPH method by introducing inverse kernels
Directory of Open Access Journals (Sweden)
Le Fang
2017-02-01
Full Text Available The smoothed particle hydrodynamics (SPH method is usually expected to be an efficient numerical tool for calculating the fluid-structure interactions in compressors; however, an endogenetic restriction is the problem of low-order consistency. A high-order SPH method by introducing inverse kernels, which is quite easy to be implemented but efficient, is proposed for solving this restriction. The basic inverse method and the special treatment near boundary are introduced with also the discussion of the combination of the Least-Square (LS and Moving-Least-Square (MLS methods. Then detailed analysis in spectral space is presented for people to better understand this method. Finally we show three test examples to verify the method behavior.
Study on the runout of granular columns with SPH methods.
He, Xuzhen; Liang, Dongfang
2015-01-01
Landslides are catastrophic geophysical phenomena, which may cause heavy fatality and property losses. Hence, it is of vital importance to understand their mechanisms and evaluate their travel distance, so that appropriate measures can be taken to mitigate their risk. This paper reports on an application of the incompressible Smoothed Particle Hydrodynamics (SPH) method to the simulation of the collapse of granular columns onto the planes of different slopes, which is similar to dry landslide...
Advanced graphical user interface for multi-physics simulations using AMST
Hoffmann, Florian; Vogel, Frank
2017-07-01
Numerical modelling of particulate matter has gained much popularity in recent decades. Advanced Multi-physics Simulation Technology (AMST) is a state-of-the-art three dimensional numerical modelling technique combining the eX-tended Discrete Element Method (XDEM) with Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) [1]. One major limitation of this code is the lack of a graphical user interface (GUI) meaning that all pre-processing has to be made directly in a HDF5-file. This contribution presents the first graphical pre-processor developed for AMST.
Are dSph galaxies Galactic building blocks?
Directory of Open Access Journals (Sweden)
Gilmore G.
2012-02-01
Full Text Available Dwarf spheroidal galaxies (dSph are frequently assumed to represent surviving examples of a vast now destroyed population of small systems in which many of the stars now forming the Milky Way were formed. Ongoing accretion and considerable sub-structure in the outer Galactic halo is direct evidence that there is some role for stars formed in small galaxies in populating the (outer galaxy. The evidence from stellar populations is however contradictory to this. dSph stellar populations are unlike any stars found in significant numbers in the Milky Way. The dSph are indeed small galaxies, formed over long times with low rates of star formation. Most of the stars in the Milky Way halo however seem to have formed quickly, at higher star formation rate, in gas mixed efficiently on kpc scales. The overwhelming majority of Milky Way stars, those in the Galactic thick disk and thin disk, seem to have nothing at all to do with dwarf galaxy origins.
SPH Modelling of Sea-ice Pack Dynamics
Staroszczyk, Ryszard
2017-12-01
The paper is concerned with the problem of sea-ice pack motion and deformation under the action of wind and water currents. Differential equations describing the dynamics of ice, with its very distinct mateFfigrial responses in converging and diverging flows, express the mass and linear momentum balances on the horizontal plane (the free surface of the ocean). These equations are solved by the fully Lagrangian method of smoothed particle hydrodynamics (SPH). Assuming that the ice behaviour can be approximated by a non-linearly viscous rheology, the proposed SPH model has been used to simulate the evolution of a sea-ice pack driven by wind drag stresses. The results of numerical simulations illustrate the evolution of an ice pack, including variations in ice thickness and ice area fraction in space and time. The effects of different initial ice pack configurations and of different conditions assumed at the coast-ice interface are examined. In particular, the SPH model is applied to a pack flow driven by a vortex wind to demonstrate how well the Lagrangian formulation can capture large deformations and displacements of sea ice.
Multiphysics modelling and experimental validation of high concentration photovoltaic modules
International Nuclear Information System (INIS)
Theristis, Marios; Fernández, Eduardo F.; Sumner, Mike; O'Donovan, Tadhg S.
2017-01-01
Highlights: • A multiphysics modelling approach for concentrating photovoltaics was developed. • An experimental campaign was conducted to validate the models. • The experimental results were in good agreement with the models. • The multiphysics modelling allows the concentrator’s optimisation. - Abstract: High concentration photovoltaics, equipped with high efficiency multijunction solar cells, have great potential in achieving cost-effective and clean electricity generation at utility scale. Such systems are more complex compared to conventional photovoltaics because of the multiphysics effect that is present. Modelling the power output of such systems is therefore crucial for their further market penetration. Following this line, a multiphysics modelling procedure for high concentration photovoltaics is presented in this work. It combines an open source spectral model, a single diode electrical model and a three-dimensional finite element thermal model. In order to validate the models and the multiphysics modelling procedure against actual data, an outdoor experimental campaign was conducted in Albuquerque, New Mexico using a high concentration photovoltaic monomodule that is thoroughly described in terms of its geometry and materials. The experimental results were in good agreement (within 2.7%) with the predicted maximum power point. This multiphysics approach is relatively more complex when compared to empirical models, but besides the overall performance prediction it can also provide better understanding of the physics involved in the conversion of solar irradiance into electricity. It can therefore be used for the design and optimisation of high concentration photovoltaic modules.
A challenge to dSph formation models: are the most isolated Local Group dSph galaxies truly old?
Monelli, Matteo
2017-08-01
What is the origin of the different dwarf galaxy types? The classification into dwarf irregular (dIrr), spheroidal (dSph), and transition (dT) types is based on their present-day properties. However, star formation histories (SFHs) reconstructed from deep color-magnitude diagrams (CMDs) provide details on the early evolution of galaxies of all these types, and indicate only two basic evolutionary paths. One is characterized by a vigorous but brief initial star-forming event, and little or no star formation thereafter (fast evolution), and the other one by roughly continuous star formation until (nearly) the present time (slow evolution). These two paths do not map directly onto the dIrr, dT and dSph types. Thus, the present galaxy properties do not reflect their lifetime evolution. Since there are some indications that slow dwarfs were assembled in lower-density environments than fast dwarfs, Gallart et al (2015) proposed that the distinction between fast and slow dwarfs reflects the characteristic density of the environment where they formed. This scenario, and more generally scenarios where dSph galaxies formed through the interaction with a massive galaxy, are challenged by a small sample of extremely isolated dSph/dT in the outer fringes of the Local Group. This proposal targets two of these objects (VV124, KKR25) for which we will infer their SFH - through a novel technique that combines the information from their RR Lyrae stars and deep CMDs sampling the intermediate-age population - in order to test these scenarios. This is much less demanding on observing time than classical SFH derivation using full depth CMDs.
International Nuclear Information System (INIS)
Zhang, Jinzhao; Segurado, Jacobo; Schneidesch, Christophe
2013-01-01
Since 1980's, Tractebel Engineering (TE) has being developed and applied a multi-physical modelling and safety analyses capability, based on a code package consisting of the best estimate 3D neutronic (PANTHER), system thermal hydraulic (RELAP5), core sub-channel thermal hydraulic (COBRA-3C), and fuel thermal mechanic (FRAPCON/FRAPTRAN) codes. A series of methodologies have been developed to perform and to license the reactor safety analysis and core reload design, based on the deterministic bounding approach. Following the recent trends in research and development as well as in industrial applications, TE has been working since 2010 towards the application of the statistical sensitivity and uncertainty analysis methods to the multi-physical modelling and licensing safety analyses. In this paper, the TE multi-physical modelling and safety analyses capability is first described, followed by the proposed TE best estimate plus statistical uncertainty analysis method (BESUAM). The chosen statistical sensitivity and uncertainty analysis methods (non-parametric order statistic method or bootstrap) and tool (DAKOTA) are then presented, followed by some preliminary results of their applications to FRAPCON/FRAPTRAN simulation of OECD RIA fuel rod codes benchmark and RELAP5/MOD3.3 simulation of THTF tests. (authors)
Energy Technology Data Exchange (ETDEWEB)
Qiu, Yuefeng, E-mail: yuefeng.qiu@kit.edu; Lu, Lei; Fischer, Ulrich
2015-10-15
Highlights: • Integrated approach for neutronics, thermal and structural analyses was developed. • MCNP5/6, TRIPOLI-4 were coupled with CFX, Fluent and ANSYS Workbench. • A novel meshing approach has been proposed for describing MC geometry. - Abstract: Coupled multi-physics analyses on fusion reactor devices require high-fidelity neutronic models, and flexible, accurate data exchanging between various calculation codes. An integrated coupling approach has been developed to enable the conversion of CAD, mesh, or hybrid geometries for Monte Carlo (MC) codes MCNP5/6, TRIPOLI-4, and translation of nuclear heating data for CFD codes Fluent, CFX and structural mechanical software ANSYS Workbench. The coupling approach has been implemented based on SALOME platform with CAD modeling, mesh generation and data visualization capabilities. A novel meshing approach has been developed for generating suitable meshes for MC geometry descriptions. The coupling approach has been concluded to be reliable and efficient after verification calculations of several application cases.
Energy Technology Data Exchange (ETDEWEB)
Kim, Seung Jun [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-07-17
The current study aims to predict the steady state power of a generic solution vessel and to develop a corresponding heat transfer coefficient correlation for a Moly99 production facility by conducting a fully coupled multi-physics simulation. A prediction of steady state power for the current application is inherently interconnected between thermal hydraulic characteristics (i.e. Multiphase computational fluid dynamics solved by ANSYS-Fluent 17.2) and the corresponding neutronic behavior (i.e. particle transport solved by MCNP6.2) in the solution vessel. Thus, the development of a coupling methodology is vital to understand the system behavior at a variety of system design and postulated operating scenarios. In this study, we report on the k-effective (keff) calculation for the baseline solution vessel configuration with a selected solution concentration using MCNP K-code modeling. The associated correlation of thermal properties (e.g. density, viscosity, thermal conductivity, specific heat) at the selected solution concentration are developed based on existing experimental measurements in the open literature. The numerical coupling methodology between multiphase CFD and MCNP is successfully demonstrated, and the detailed coupling procedure is documented. In addition, improved coupling methods capturing realistic physics in the solution vessel thermal-neutronic dynamics are proposed and tested further (i.e. dynamic height adjustment, mull-cell approach). As a key outcome of the current study, a multi-physics coupling methodology between MCFD and MCNP is demonstrated and tested for four different operating conditions. Those different operating conditions are determined based on the neutron source strength at a fixed geometry condition. The steady state powers for the generic solution vessel at various operating conditions are reported, and a generalized correlation of the heat transfer coefficient for the current application is discussed. The assessment of multi-physics
Multiphysics Integrated Coupling Environment (MICE) User Manual
Energy Technology Data Exchange (ETDEWEB)
Varija Agarwal; Donna Post Guillen
2013-08-01
The complex, multi-part nature of waste glass melters used in nuclear waste vitrification poses significant modeling challenges. The focus of this project has been to couple a 1D MATLAB model of the cold cap region within a melter with a 3D STAR-CCM+ model of the melter itself. The Multiphysics Integrated Coupling Environment (MICE) has been developed to create a cohesive simulation of a waste glass melter that accurately represents the cold cap. The one-dimensional mathematical model of the cold cap uses material properties, axial heat, and mass fluxes to obtain a temperature profile for the cold cap, the region where feed-to-glass conversion occurs. The results from Matlab are used to update simulation data in the three-dimensional STAR-CCM+ model so that the cold cap is appropriately incorporated into the 3D simulation. The two processes are linked through ModelCenter integration software using time steps that are specified for each process. Data is to be exchanged circularly between the two models, as the inputs and outputs of each model depend on the other.
Optimization of coupled multiphysics methodology for safety analysis of pebble bed modular reactor
Mkhabela, Peter Tshepo
The research conducted within the framework of this PhD thesis is devoted to the high-fidelity multi-physics (based on neutronics/thermal-hydraulics coupling) analysis of Pebble Bed Modular Reactor (PBMR), which is a High Temperature Reactor (HTR). The Next Generation Nuclear Plant (NGNP) will be a HTR design. The core design and safety analysis methods are considerably less developed and mature for HTR analysis than those currently used for Light Water Reactors (LWRs). Compared to LWRs, the HTR transient analysis is more demanding since it requires proper treatment of both slower and much longer transients (of time scale in hours and days) and fast and short transients (of time scale in minutes and seconds). There is limited operation and experimental data available for HTRs for validation of coupled multi-physics methodologies. This PhD work developed and verified reliable high fidelity coupled multi-physics models subsequently implemented in robust, efficient, and accurate computational tools to analyse the neutronics and thermal-hydraulic behaviour for design optimization and safety evaluation of PBMR concept The study provided a contribution to a greater accuracy of neutronics calculations by including the feedback from thermal hydraulics driven temperature calculation and various multi-physics effects that can influence it. Consideration of the feedback due to the influence of leakage was taken into account by development and implementation of improved buckling feedback models. Modifications were made in the calculation procedure to ensure that the xenon depletion models were accurate for proper interpolation from cross section tables. To achieve this, the NEM/THERMIX coupled code system was developed to create the system that is efficient and stable over the duration of transient calculations that last over several tens of hours. Another achievement of the PhD thesis was development and demonstration of full-physics, three-dimensional safety analysis
Design and multi-physics optimization of rotary MRF brakes
Topcu, Okan; Taşcıoğlu, Yiğit; Konukseven, Erhan İlhan
2018-03-01
Particle swarm optimization (PSO) is a popular method to solve the optimization problems. However, calculations for each particle will be excessive when the number of particles and complexity of the problem increases. As a result, the execution speed will be too slow to achieve the optimized solution. Thus, this paper proposes an automated design and optimization method for rotary MRF brakes and similar multi-physics problems. A modified PSO algorithm is developed for solving multi-physics engineering optimization problems. The difference between the proposed method and the conventional PSO is to split up the original single population into several subpopulations according to the division of labor. The distribution of tasks and the transfer of information to the next party have been inspired by behaviors of a hunting party. Simulation results show that the proposed modified PSO algorithm can overcome the problem of heavy computational burden of multi-physics problems while improving the accuracy. Wire type, MR fluid type, magnetic core material, and ideal current inputs have been determined by the optimization process. To the best of the authors' knowledge, this multi-physics approach is novel for optimizing rotary MRF brakes and the developed PSO algorithm is capable of solving other multi-physics engineering optimization problems. The proposed method has showed both better performance compared to the conventional PSO and also has provided small, lightweight, high impedance rotary MRF brake designs.
Multiphysics Modelling and Simulation for Systems Design Conference
Abbes, Mohamed; Choley, Jean-Yves; Boukharouba, Taoufik; Elnady, Tamer; Kanaev, Andrei; Amar, Mounir; Chaari, Fakher
2015-01-01
This book reports on the state of the art in the field of multiphysics systems. It consists of accurately reviewed contributions to the MMSSD’2014 conference, which was held from December 17 to 19, 2004 in Hammamet, Tunisia. The different chapters, covering new theories, methods and a number of case studies, provide readers with an up-to-date picture of multiphysics modeling and simulation. They highlight the role played by high-performance computing and newly available software in promoting the study of multiphysics coupling effects, and show how these technologies can be practically implemented to bring about significant improvements in the field of design, control and monitoring of machines. In addition to providing a detailed description of the methods and their applications, the book also identifies new research issues, challenges and opportunities, thus providing researchers and practitioners with both technical information to support their daily work and a new source of inspiration for their future...
Multiphysics modeling using COMSOL a first principles approach
Pryor, Roger W
2011-01-01
Multiphysics Modeling Using COMSOL rapidly introduces the senior level undergraduate, graduate or professional scientist or engineer to the art and science of computerized modeling for physical systems and devices. It offers a step-by-step modeling methodology through examples that are linked to the Fundamental Laws of Physics through a First Principles Analysis approach. The text explores a breadth of multiphysics models in coordinate systems that range from 1D to 3D and introduces the readers to the numerical analysis modeling techniques employed in the COMSOL Multiphysics software. After readers have built and run the examples, they will have a much firmer understanding of the concepts, skills, and benefits acquired from the use of computerized modeling techniques to solve their current technological problems and to explore new areas of application for their particular technological areas of interest.
Tightly Coupled Multiphysics Algorithm for Pebble Bed Reactors
International Nuclear Information System (INIS)
Park, HyeongKae; Knoll, Dana; Gaston, Derek; Martineau, Richard
2010-01-01
We have developed a tightly coupled multiphysics simulation tool for the pebble-bed reactor (PBR) concept, a type of Very High-Temperature gas-cooled Reactor (VHTR). The simulation tool, PRONGHORN, takes advantages of the Multiphysics Object-Oriented Simulation Environment library, and is capable of solving multidimensional thermal-fluid and neutronics problems implicitly with a Newton-based approach. Expensive Jacobian matrix formation is alleviated via the Jacobian-free Newton-Krylov method, and physics-based preconditioning is applied to minimize Krylov iterations. Motivation for the work is provided via analysis and numerical experiments on simpler multiphysics reactor models. We then provide detail of the physical models and numerical methods in PRONGHORN. Finally, PRONGHORN's algorithmic capability is demonstrated on a number of PBR test cases.
Impacts modeling using the SPH particulate method. Case study
International Nuclear Information System (INIS)
Debord, R.
1999-01-01
The aim of this study is the modeling of the impact of melted metal on the reactor vessel head in the case of a core-meltdown accident. Modeling using the classical finite-element method alone is not sufficient but requires a coupling with particulate methods in order to take into account the behaviour of the corium. After a general introduction about particulate methods, the Nabor and SPH (smoothed particle hydrodynamics) methods are described. Then, the theoretical and numerical reliability of the SPH method is determined using simple cases. In particular, the number of neighbours significantly influences the preciseness of calculations. Also, the mesh of the structure must be adapted to the mesh of the fluid in order to reduce the edge effects. Finally, this study has shown that the values of artificial velocity coefficients used in the simulation of the BERDA test performed by the FZK Karlsruhe (Germany) are not correct. The domain of use of these coefficients was precised during a low speed impact. (J.S.)
COMSOL Multiphysics Model for HLW Canister Filling
Energy Technology Data Exchange (ETDEWEB)
Kesterson, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
2016-04-11
The U.S. Department of Energy (DOE) is building a Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is being temporarily stored in 177 underground tanks. Efforts are being made to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. Wastes containing high concentrations of Al_{2}O_{3} and Na_{2}O can contribute to nepheline (generally NaAlSiO_{4}) crystallization, which can sharply reduce the chemical durability of high level waste (HLW) glass. Nepheline crystallization can occur during slow cooling of the glass within the stainless steel canister. The purpose of this work was to develop a model that can be used to predict temperatures of the glass in a WTP HLW canister during filling and cooling. The intent of the model is to support scoping work in the laboratory. It is not intended to provide precise predictions of temperature profiles, but rather to provide a simplified representation of glass cooling profiles within a full scale, WTP HLW canister under various glass pouring rates. These data will be used to support laboratory studies for an improved understanding of the mechanisms of nepheline crystallization. The model was created using COMSOL Multiphysics, a commercially available software. The model results were compared to available experimental data, TRR-PLT-080, and were found to yield sufficient results for the scoping nature of the study. The simulated temperatures were within 60 ºC for the centerline, 0.0762m (3 inch) from centerline, and 0.2286m (9 inch) from centerline thermocouples once the thermocouples were covered with glass. The temperature difference between the experimental and simulated values reduced to 40 ºC, 4 hours after the thermocouple was covered, and down to 20 ºC, 6 hours after the thermocouple was covered
Dynamic simulations of geologic materials using combined FEM/DEM/SPH analysis
Energy Technology Data Exchange (ETDEWEB)
Morris, J P; Johnson, S M
2008-03-26
An overview of the Lawrence Discrete Element Code (LDEC) is presented, and results from a study investigating the effect of explosive and impact loading on geologic materials using the Livermore Distinct Element Code (LDEC) are detailed. LDEC was initially developed to simulate tunnels and other structures in jointed rock masses using large numbers of polyhedral blocks. Many geophysical applications, such as projectile penetration into rock, concrete targets, and boulder fields, require a combination of continuum and discrete methods in order to predict the formation and interaction of the fragments produced. In an effort to model this class of problems, LDEC now includes implementations of Cosserat point theory and cohesive elements. This approach directly simulates the transition from continuum to discontinuum behavior, thereby allowing for dynamic fracture within a combined finite element/discrete element framework. In addition, there are many application involving geologic materials where fluid-structure interaction is important. To facilitate solution of this class of problems a Smooth Particle Hydrodynamics (SPH) capability has been incorporated into LDEC to simulate fully coupled systems involving geologic materials and a saturating fluid. We will present results from a study of a broad range of geomechanical problems that exercise the various components of LDEC in isolation and in tandem.
Final report on LDRD project : coupling strategies for multi-physics applications.
Energy Technology Data Exchange (ETDEWEB)
Hopkins, Matthew Morgan; Moffat, Harry K.; Carnes, Brian; Hooper, Russell Warren; Pawlowski, Roger P.
2007-11-01
Many current and future modeling applications at Sandia including ASC milestones will critically depend on the simultaneous solution of vastly different physical phenomena. Issues due to code coupling are often not addressed, understood, or even recognized. The objectives of the LDRD has been both in theory and in code development. We will show that we have provided a fundamental analysis of coupling, i.e., when strong coupling vs. a successive substitution strategy is needed. We have enabled the implementation of tighter coupling strategies through additions to the NOX and Sierra code suites to make coupling strategies available now. We have leveraged existing functionality to do this. Specifically, we have built into NOX the capability to handle fully coupled simulations from multiple codes, and we have also built into NOX the capability to handle Jacobi Free Newton Krylov simulations that link multiple applications. We show how this capability may be accessed from within the Sierra Framework as well as from outside of Sierra. The critical impact from this LDRD is that we have shown how and have delivered strategies for enabling strong Newton-based coupling while respecting the modularity of existing codes. This will facilitate the use of these codes in a coupled manner to solve multi-physic applications.
The Integrated Plasma Simulator: A Flexible Python Framework for Coupled Multiphysics Simulation
Energy Technology Data Exchange (ETDEWEB)
Foley, Samantha S [ORNL; Elwasif, Wael R [ORNL; Bernholdt, David E [ORNL
2011-11-01
High-fidelity coupled multiphysics simulations are an increasingly important aspect of computational science. In many domains, however, there has been very limited experience with simulations of this sort, therefore research in coupled multiphysics often requires computational frameworks with significant flexibility to respond to the changing directions of the physics and mathematics. This paper presents the Integrated Plasma Simulator (IPS), a framework designed for loosely coupled simulations of fusion plasmas. The IPS provides users with a simple component architecture into which a wide range of existing plasma physics codes can be inserted as components. Simulations can take advantage of multiple levels of parallelism supported in the IPS, and can be controlled by a high-level ``driver'' component, or by other coordination mechanisms, such as an asynchronous event service. We describe the requirements and design of the framework, and how they were implemented in the Python language. We also illustrate the flexibility of the framework by providing examples of different types of simulations that utilize various features of the IPS.
Efficient topology optimisation of multiscale and multiphysics problems
DEFF Research Database (Denmark)
Alexandersen, Joe
The aim of this Thesis is to present efficient methods for optimising high-resolution problems of a multiscale and multiphysics nature. The Thesis consists of two parts: one treating topology optimisation of microstructural details and the other treating topology optimisation of conjugate heat...
A survey of open source multiphysics frameworks in engineering
Babur, O.; Smilauer, V.; Verhoeff, T.; Brand, van den M.G.J.
2015-01-01
This paper presents a systematic survey of open source multiphysics frameworks in the en- gineering domains. These domains share many commonalities despite the diverse application areas. A thorough search for the available frameworks with both academic and industrial ori- gins has revealed numerous
Predictive modeling of coupled multi-physics systems: I. Theory
International Nuclear Information System (INIS)
Cacuci, Dan Gabriel
2014-01-01
Highlights: • We developed “predictive modeling of coupled multi-physics systems (PMCMPS)”. • PMCMPS reduces predicted uncertainties in predicted model responses and parameters. • PMCMPS treats efficiently very large coupled systems. - Abstract: This work presents an innovative mathematical methodology for “predictive modeling of coupled multi-physics systems (PMCMPS).” This methodology takes into account fully the coupling terms between the systems but requires only the computational resources that would be needed to perform predictive modeling on each system separately. The PMCMPS methodology uses the maximum entropy principle to construct an optimal approximation of the unknown a priori distribution based on a priori known mean values and uncertainties characterizing the parameters and responses for both multi-physics models. This “maximum entropy”-approximate a priori distribution is combined, using Bayes’ theorem, with the “likelihood” provided by the multi-physics simulation models. Subsequently, the posterior distribution thus obtained is evaluated using the saddle-point method to obtain analytical expressions for the optimally predicted values for the multi-physics models parameters and responses along with corresponding reduced uncertainties. Noteworthy, the predictive modeling methodology for the coupled systems is constructed such that the systems can be considered sequentially rather than simultaneously, while preserving exactly the same results as if the systems were treated simultaneously. Consequently, very large coupled systems, which could perhaps exceed available computational resources if treated simultaneously, can be treated with the PMCMPS methodology presented in this work sequentially and without any loss of generality or information, requiring just the resources that would be needed if the systems were treated sequentially
Simulation of the effect of defence structures on granular flows using SPH
Directory of Open Access Journals (Sweden)
P. Lachamp
2002-01-01
Full Text Available This paper presents the SPH (Smoothed Particles Hydrodynamics numerical method adapted to complex rheology and free surface flow. It has been developed to simulate the local effect of a simple obstacle on a granular flow. We have introduced this specific rheology to the classical formalism of the method and thanks to experimental devices, we were able to validate the results. Two viscosity values have been simultaneously computed to simulate "plugs" and "dead zone" with the same code. First, some experiments have been done on a simple inclined slope to show the accuracy of the numerical results. We have fixed the mass flow rate to see the variations of the flow depth according to the channel slope. Then we put a weir to block the flow and we analysed the dependence between the obstacle height and the length of influence upstream from the obstacle. After having shown that numerical results were consistent, we have studied speed profiles and pressure impact on the structure. Also results with any topography will be presented. This will have a great interest to study real flow over natural topography while using the model for decision help.
Directory of Open Access Journals (Sweden)
E Holzbecher
2016-03-01
Full Text Available In a classical paper Henry set up a conceptual model for simulating saltwater intrusion into coastal aquifers. Up to now the problem has been taken up by software developers and modellers as a benchmark for codes simulating coupled flow and transport in porous media. The Henry test case has been treated using different numerical methods based on various formulations of differential equations. We compare several of these approaches using multiphysics software. We model the problem using Finite Elements, utilizing the primitive variables and the streamfunction approach, both with and without using the Oberbeck-Boussinesq assumption. We compare directly coupled solvers with segregated solver strategies. Changing finite element orders and mesh refinement, we find that models based on the streamfunction converge 2-4 times faster than runs based on primitive variables. Concerning the solution strategy, we find an advantage of Picard iterations compared to monolithic Newton iterations.
Module-based Hybrid Uncertainty Quantification for Multi-physics Applications: Theory and Software
Energy Technology Data Exchange (ETDEWEB)
Tong, Charles [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chen, Xiao [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Iaccarino, Gianluca [Stanford Univ., CA (United States); Mittal, Akshay [Stanford Univ., CA (United States)
2013-10-08
In this project we proposed to develop an innovative uncertainty quantification methodology that captures the best of the two competing approaches in UQ, namely, intrusive and non-intrusive approaches. The idea is to develop the mathematics and the associated computational framework and algorithms to facilitate the use of intrusive or non-intrusive UQ methods in different modules of a multi-physics multi-module simulation model in a way that physics code developers for different modules are shielded (as much as possible) from the chores of accounting for the uncertain ties introduced by the other modules. As the result of our research and development, we have produced a number of publications, conference presentations, and a software product.
Little Bear’s pulsating stars: Variable star census of UMi dSph Galaxy
Directory of Open Access Journals (Sweden)
Kinemuchi K.
2017-01-01
Full Text Available Recent observations and a photometric search for variable stars in the Ursa Minor dwarf spheroidal galaxy (UMi dSph are presented. Our observations were taken at Apache Point Observatory in 2014 and 2016 using the 0.5m ARCSAT telescope and the West Mountain Observatory (WMO 0.9m telescope of Brigham Young University in 2016. Previously known RR Lyrae stars in our field of view of the UMi dSph are identified, and we also catalog new variable star candidates. Tentative classifications are given for some of the new variable stars. We have conducted period searches with the data collected with the WMO telescope. Our ultimate goal is to create an updated catalog of variable stars in the UMi dSph and to compare the RR Lyrae stellar characteristics to other RR Lyrae stars found in the Local Group dSph galaxies.
Zhang, Qiu-xia; Liu, Hai-peng; Chen, Rong-yuan; Shen, Kai-li; Wang, Ke-jian
2013-01-01
Clip domain serine proteinase homologs are involved in many biological processes including immune response. To identify the immune function of a serine proteinase homolog (Sp-SPH), originally isolated from hemocytes of the mud crab, Scylla paramamosain, the Sp-SPH was expressed recombinantly and purified for further studies. It was found that the Sp-SPH protein could bind to a number of bacteria (including Aeromonas hydrophila, Escherichia coli, Staphylococcus aureus, Vibrio fluvialis, Vibrio harveyi and Vibrio parahemolyticus), bacterial cell wall components such as lipopolysaccharide or peptidoglycan (PGN), and β-1, 3-glucan of fungus. But no direct antibacterial activity of Sp-SPH protein was shown by using minimum inhibitory concentration or minimum bactericidal concentration assays. Nevertheless, the Sp-SPH protein was found to significantly enhance the crab hemocyte adhesion activity (paired t-test, Pparahemolyticus which were both recognized by Sp-SPH protein, if pre-incubated with Sp-SPH protein, respectively. Whereas, the crabs died much faster when challenged with Vibrio alginolyiicus, a pathogenic bacterium not recognized by Sp-SPH protein, compared to those of crabs challenged with A. hydrophila or V. parahemolyticus when pre-coated with Sp-SPH protein. Taken together, these data suggested that Sp-SPH molecule might play an important role in immune defense against bacterial infection in the mud crab S. paramamosain.
Zhang, Qiu-xia; Liu, Hai-peng; Chen, Rong-yuan; Shen, Kai-li; Wang, Ke-jian
2013-01-01
Clip domain serine proteinase homologs are involved in many biological processes including immune response. To identify the immune function of a serine proteinase homolog (Sp-SPH), originally isolated from hemocytes of the mud crab, Scylla paramamosain, the Sp-SPH was expressed recombinantly and purified for further studies. It was found that the Sp-SPH protein could bind to a number of bacteria (including Aeromonas hydrophila, Escherichia coli, Staphylococcus aureus, Vibrio fluvialis, Vibrio harveyi and Vibrio parahemolyticus), bacterial cell wall components such as lipopolysaccharide or peptidoglycan (PGN), and β-1, 3-glucan of fungus. But no direct antibacterial activity of Sp-SPH protein was shown by using minimum inhibitory concentration or minimum bactericidal concentration assays. Nevertheless, the Sp-SPH protein was found to significantly enhance the crab hemocyte adhesion activity (paired t-test, Pparahemolyticus which were both recognized by Sp-SPH protein, if pre-incubated with Sp-SPH protein, respectively. Whereas, the crabs died much faster when challenged with Vibrio alginolyiicus, a pathogenic bacterium not recognized by Sp-SPH protein, compared to those of crabs challenged with A. hydrophila or V. parahemolyticus when pre-coated with Sp-SPH protein. Taken together, these data suggested that Sp-SPH molecule might play an important role in immune defense against bacterial infection in the mud crab S. paramamosain. PMID:23724001
Multi-physic simulations of irradiation experiments in a technological irradiation reactor
International Nuclear Information System (INIS)
Bonaccorsi, Th.
2007-09-01
A Material Testing Reactor (MTR) makes it possible to irradiate material samples under intense neutron and photonic fluxes. These experiments are carried out in experimental devices localised in the reactor core or in periphery (reflector). Available physics simulation tools only treat, most of the time, one physics field in a very precise way. Multi-physic simulations of irradiation experiments therefore require a sequential use of several calculation codes and data exchanges between these codes: this corresponds to problems coupling. In order to facilitate multi-physic simulations, this thesis sets up a data model based on data-processing objects, called Technological Entities. This data model is common to all of the physics fields. It permits defining the geometry of an irradiation device in a parametric way and to associate information about materials to it. Numerical simulations are encapsulated into interfaces providing the ability to call specific functionalities with the same command (to initialize data, to launch calculations, to post-treat, to get results,... ). Thus, once encapsulated, numerical simulations can be re-used for various studies. This data model is developed in a SALOME platform component. The first application case made it possible to perform neutronic simulations (OSIRIS reactor and RJH) coupled with fuel behavior simulations. In a next step, thermal hydraulics could also be taken into account. In addition to the improvement of the calculation accuracy due to the physical phenomena coupling, the time spent in the development phase of the simulation is largely reduced and the possibilities of uncertainty treatment are under consideration. (author)
Advanced Mesh-Enabled Monte carlo capability for Multi-Physics Reactor Analysis
Energy Technology Data Exchange (ETDEWEB)
Wilson, Paul; Evans, Thomas; Tautges, Tim
2012-12-24
This project will accumulate high-precision fluxes throughout reactor geometry on a non- orthogonal grid of cells to support multi-physics coupling, in order to more accurately calculate parameters such as reactivity coefficients and to generate multi-group cross sections. This work will be based upon recent developments to incorporate advanced geometry and mesh capability in a modular Monte Carlo toolkit with computational science technology that is in use in related reactor simulation software development. Coupling this capability with production-scale Monte Carlo radiation transport codes can provide advanced and extensible test-beds for these developments. Continuous energy Monte Carlo methods are generally considered to be the most accurate computational tool for simulating radiation transport in complex geometries, particularly neutron transport in reactors. Nevertheless, there are several limitations for their use in reactor analysis. Most significantly, there is a trade-off between the fidelity of results in phase space, statistical accuracy, and the amount of computer time required for simulation. Consequently, to achieve an acceptable level of statistical convergence in high-fidelity results required for modern coupled multi-physics analysis, the required computer time makes Monte Carlo methods prohibitive for design iterations and detailed whole-core analysis. More subtly, the statistical uncertainty is typically not uniform throughout the domain, and the simulation quality is limited by the regions with the largest statistical uncertainty. In addition, the formulation of neutron scattering laws in continuous energy Monte Carlo methods makes it difficult to calculate adjoint neutron fluxes required to properly determine important reactivity parameters. Finally, most Monte Carlo codes available for reactor analysis have relied on orthogonal hexahedral grids for tallies that do not conform to the geometric boundaries and are thus generally not well
Towards an efficient multiphysics model for nuclear reactor dynamics
Directory of Open Access Journals (Sweden)
Obaidurrahman K.
2015-01-01
Full Text Available Availability of fast computer resources nowadays has facilitated more in-depth modeling of complex engineering systems which involve strong multiphysics interactions. This multiphysics modeling is an important necessity in nuclear reactor safety studies where efforts are being made worldwide to combine the knowledge from all associated disciplines at one place to accomplish the most realistic simulation of involved phenomenon. On these lines coupled modeling of nuclear reactor neutron kinetics, fuel heat transfer and coolant transport is a regular practice nowadays for transient analysis of reactor core. However optimization between modeling accuracy and computational economy has always been a challenging task to ensure the adequate degree of reliability in such extensive numerical exercises. Complex reactor core modeling involves estimation of evolving 3-D core thermal state, which in turn demands an expensive multichannel based detailed core thermal hydraulics model. A novel approach of power weighted coupling between core neutronics and thermal hydraulics presented in this work aims to reduce the bulk of core thermal calculations in core dynamics modeling to a significant extent without compromising accuracy of computation. Coupled core model has been validated against a series of international benchmarks. Accuracy and computational efficiency of the proposed multiphysics model has been demonstrated by analyzing a reactivity initiated transient.
A MULTIDIMENSIONAL AND MULTIPHYSICS APPROACH TO NUCLEAR FUEL BEHAVIOR SIMULATION
Energy Technology Data Exchange (ETDEWEB)
R. L. Williamson; J. D. Hales; S. R. Novascone; M. R. Tonks; D. R. Gaston; C. J. Permann; D. Andrs; R. C. Martineau
2012-04-01
Important aspects of fuel rod behavior, for example pellet-clad mechanical interaction (PCMI), fuel fracture, oxide formation, non-axisymmetric cooling, and response to fuel manufacturing defects, are inherently multidimensional in addition to being complicated multiphysics problems. Many current modeling tools are strictly 2D axisymmetric or even 1.5D. This paper outlines the capabilities of a new fuel modeling tool able to analyze either 2D axisymmetric or fully 3D models. These capabilities include temperature-dependent thermal conductivity of fuel; swelling and densification; fuel creep; pellet fracture; fission gas release; cladding creep; irradiation growth; and gap mechanics (contact and gap heat transfer). The need for multiphysics, multidimensional modeling is then demonstrated through a discussion of results for a set of example problems. The first, a 10-pellet rodlet, demonstrates the viability of the solution method employed. This example highlights the effect of our smeared cracking model and also shows the multidimensional nature of discrete fuel pellet modeling. The second example relies on our the multidimensional, multiphysics approach to analyze a missing pellet surface problem. As a final example, we show a lower-length-scale simulation coupled to a continuum-scale simulation.
IMPETUS: Consistent SPH calculations of 3D spherical Bondi accretion onto a black hole
Ramírez-Velasquez, J. M.; Sigalotti, L. Di G.; Gabbasov, R.; Cruz, F.; Klapp, J.
2018-04-01
We present three-dimensional calculations of spherically symmetric Bondi accretion onto a stationary supermassive black hole (SMBH) of mass 108M⊙ within a radial range of 0.02 - 10 pc, using a modified version of the smoothed particle hydrodynamics (SPH) GADGET-2 code, which ensures approximate first-order consistency (i.e., second-order accuracy) for the particle approximation. First-order consistency is restored by allowing the number of neighbours, nneigh, and the smoothing length, h, to vary with the total number of particles, N, such that the asymptotic limits nneigh → ∞ and h → 0 hold as N → ∞. The ability of the method to reproduce the isothermal (γ = 1) and adiabatic (γ = 5/3) Bondi accretion is investigated with increased spatial resolution. In particular, for the isothermal models the numerical radial profiles closely match the Bondi solution, except near the accretor, where the density and radial velocity are slightly underestimated. However, as nneigh is increased and h is decreased, the calculations approach first-order consistency and the deviations from the Bondi solution decrease. The density and radial velocity profiles for the adiabatic models are qualitatively similar to those for the isothermal Bondi accretion. Steady-state Bondi accretion is reproduced by the highly resolved consistent models with a percent relative error of ≲ 1% for γ = 1 and ˜9% for γ = 5/3, with the adiabatic accretion taking longer than the isothermal case to reach steady flow. The performance of the method is assessed by comparing the results with those obtained using the standard GADGET-2 and the GIZMO codes.
A study of solid wall models for weakly compressible SPH
Energy Technology Data Exchange (ETDEWEB)
Valizadeh, Alireza, E-mail: alireza.valizadeh@monash.edu [Department of Mechanical and Aerospace Engineering, Monash University, Clayton VIC 3800 (Australia); Monaghan, Joseph J., E-mail: joe.monaghan@monash.edu [School of Mathematical Sciences, Monash University, Clayton VIC 3800 (Australia)
2015-11-01
This paper is concerned with a comparison of two methods of treating solid wall boundaries in the weakly compressible (SPH) method. They have been chosen because of their wide use in simulations. These methods are the boundary force particles of Monaghan and Kajtar [24] and the use of layers of fixed boundary particles. The latter was first introduced by Morris et al. [26] but has since been improved by Adami et al. [1] whose algorithm involves interpolating the pressure and velocity from the actual fluid to the boundary particles. For each method, we study the effect of the density diffusive terms proposed by Molteni and Colagrossi [19] and modified by Antuono et al. [3]. We test the methods by a series of simulations commencing with the time-dependent spin-down of fluid within a cylinder and the behaviour of fluid in a box subjected to constant acceleration at an angle to the walls of the box, and concluding with a dam break over a triangular obstacle. In the first two cases the results from the two methods can be compared to analytical solutions while, in the latter case, they can be compared with experiments and other methods. These results show that the method of Adami et al. together with density diffusion is in very satisfactory agreement with the experimental results and is, overall, the best of the methods discussed here.
International Nuclear Information System (INIS)
Navarro, V.; Alonso, J.; Asensio, L.; Yustres, A.; Pintado, X.
2012-01-01
Document available in extended abstract form only. The use of numerical methods, especially the Finite Element Method (FEM), for solving boundary problems in Unsaturated Soil Mechanics has experienced significant progress. Several codes, both built mainly for research purposes and commercial software, are now available. In the last years, Multi-physic Partial Differentiation Equation Solvers (MPDES) have turned out to be an interesting proposal. In this family of solvers, the user defines the governing equations and the behaviour models, generally using a computer algebra environment. The code automatically assembles and solves the equation systems, saving the user having to redefine the structures of memory storage or to implement solver algorithms. The user can focus on the definition of the physics of the problem, while it is possible to couple virtually any physical or chemical process that can be described by a PDE. This can be done, for instance, in COMSOL Multiphysics (CM). Nonetheless, the versatility of CM is compromised by the impossibility to implement models with variables defined by implicit functions. Elasto-plastic models involve an implicit coupling among stress increments, plastic strains and plastic variables increments. For this reason, they cannot be implemented in CM in a straightforward way. This means a very relevant limitation for the use of this tool in the analysis of geomechanical boundary value problems. In this work, a strategy to overcome this problem using the multi-physics concept is presented. A mixed method is proposed, considering the constitutive stresses, the pre-consolidation pressure and the plastic variables as main unknowns of the model. Mixed methods usually present stability problems. However, the algorithmics present in CM include several numerical strategies to minimise this kind of problems. Besides, CM is based on the application of the FEM with Lagrange multipliers, an approach that significantly contributes stability
The Cea multi-scale and multi-physics simulation project for nuclear applications
International Nuclear Information System (INIS)
Ledermann, P.; Chauliac, C.; Thomas, J.B.
2005-01-01
Full text of publication follows. Today numerical modelling is everywhere recognized as an essential tool of capitalization, integration and share of knowledge. For this reason, it becomes the central tool of research. Until now, the Cea developed a set of scientific software allowing to model, in each situation, the operation of whole or part of a nuclear installation and these codes are largely used in nuclear industry. However, for the future, it is essential to aim for a better accuracy, a better control of uncertainties and better performance in computing times. The objective is to obtain validated models allowing accurate predictive calculations for actual complex nuclear problems such as fuel behaviour in accidental situation. This demands to master a large and interactive set of phenomena ranging from nuclear reaction to heat transfer. To this end, Cea, with industrial partners (EDF, Framatome-ANP, ANDRA) has designed an integrated platform of calculation, devoted to the study of nuclear systems, and intended at the same time for industries and scientists. The development of this platform is under way with the start in 2005 of the integrated project NURESIM, with 18 European partners. Improvement is coming not only through a multi-scale description of all phenomena but also through an innovative design approach requiring deep functional analysis which is upstream from the development of the simulation platform itself. In addition, the studies of future nuclear systems are increasingly multidisciplinary (simultaneous modelling of core physics, thermal-hydraulics and fuel behaviour). These multi-physics and multi-scale aspects make mandatory to pay very careful attention to software architecture issues. A global platform is thus developed integrating dedicated specialized platforms: DESCARTES for core physics, NEPTUNE for thermal-hydraulics, PLEIADES for fuel behaviour, SINERGY for materials behaviour under irradiation, ALLIANCES for the performance
Nardi, Albert; Idiart, Andrés; Trinchero, Paolo; de Vries, Luis Manuel; Molinero, Jorge
2014-08-01
This paper presents the development, verification and application of an efficient interface, denoted as iCP, which couples two standalone simulation programs: the general purpose Finite Element framework COMSOL Multiphysics® and the geochemical simulator PHREEQC. The main goal of the interface is to maximize the synergies between the aforementioned codes, providing a numerical platform that can efficiently simulate a wide number of multiphysics problems coupled with geochemistry. iCP is written in Java and uses the IPhreeqc C++ dynamic library and the COMSOL Java-API. Given the large computational requirements of the aforementioned coupled models, special emphasis has been placed on numerical robustness and efficiency. To this end, the geochemical reactions are solved in parallel by balancing the computational load over multiple threads. First, a benchmark exercise is used to test the reliability of iCP regarding flow and reactive transport. Then, a large scale thermo-hydro-chemical (THC) problem is solved to show the code capabilities. The results of the verification exercise are successfully compared with those obtained using PHREEQC and the application case demonstrates the scalability of a large scale model, at least up to 32 threads.
Multiphysics Modelling of Sodium Sulfur Battery
Mason, Jerry Hunter
Due to global climate change and the desire to decrease greenhouse gas emissions, large scale energy storage has become a critical issue. Renewable energy sources such as wind and solar will not be a viable energy source unless the storage problem is solved. One of the practical and cost effective solutions for this problem is sodium sulfur batteries. These batteries are comprised of liquid electrode materials suspended in porous media and operate at relatively high temperatures (>300°C). The sodium anode and the sulfur/sodium-polysulfide cathode are separated by a solid electrolyte made of beta-alumina or NASICON material. Due to the use of porous materials in the electrodes, capillary pressure and the combination of capillary action and gravity become important. Capillary pressure has a strong dependence on the wetting phase (liquid electrode material) saturation; therefore sharp concentration gradients can occur between the inert gas and the electrode liquid, especially within the cathode. These concentration gradients can have direct impacts on the electrodynamics of the battery as they may produce areas of high electrical potential variation, which can decrease efficiency and even cause failures. Then, thermal management also becomes vital since the electrochemistry and material properties are sensitive to temperature gradients. To investigate these phenomena in detail and to attempt to improve upon battery design a multi-dimensional, multi-phase code has been developed and validated in this study. Then a porous media flow model is implemented. Transport equations for charge, mass and heat are solved in a time marching fashion using finite volume method. Material properties are calculated and updated as a function of time. The porous media model is coupled with the continuity equation and a separate diffusion equation for the liquid sodium in the melt. The total mass transport model is coupled with charge transport via Faraday's law. Results show that
Directory of Open Access Journals (Sweden)
Qiu-xia Zhang
Full Text Available Clip domain serine proteinase homologs are involved in many biological processes including immune response. To identify the immune function of a serine proteinase homolog (Sp-SPH, originally isolated from hemocytes of the mud crab, Scylla paramamosain, the Sp-SPH was expressed recombinantly and purified for further studies. It was found that the Sp-SPH protein could bind to a number of bacteria (including Aeromonas hydrophila, Escherichia coli, Staphylococcus aureus, Vibrio fluvialis, Vibrio harveyi and Vibrio parahemolyticus, bacterial cell wall components such as lipopolysaccharide or peptidoglycan (PGN, and β-1, 3-glucan of fungus. But no direct antibacterial activity of Sp-SPH protein was shown by using minimum inhibitory concentration or minimum bactericidal concentration assays. Nevertheless, the Sp-SPH protein was found to significantly enhance the crab hemocyte adhesion activity (paired t-test, P<0.05, and increase phenoloxidase activity if triggered by PGN in vitro (paired t-test, P<0.05. Importantly, the Sp-SPH protein was demonstrated to promote the survival rate of the animals after challenge with A. hydrophila or V. parahemolyticus which were both recognized by Sp-SPH protein, if pre-incubated with Sp-SPH protein, respectively. Whereas, the crabs died much faster when challenged with Vibrio alginolyiicus, a pathogenic bacterium not recognized by Sp-SPH protein, compared to those of crabs challenged with A. hydrophila or V. parahemolyticus when pre-coated with Sp-SPH protein. Taken together, these data suggested that Sp-SPH molecule might play an important role in immune defense against bacterial infection in the mud crab S. paramamosain.
Development and verification of the neutron diffusion solver for the GeN-Foam multi-physics platform
International Nuclear Information System (INIS)
Fiorina, Carlo; Kerkar, Nordine; Mikityuk, Konstantin; Rubiolo, Pablo; Pautz, Andreas
2016-01-01
Highlights: • Development and verification of a neutron diffusion solver based on OpenFOAM. • Integration in the GeN-Foam multi-physics platform. • Implementation and verification of acceleration techniques. • Implementation of isotropic discontinuity factors. • Automatic adjustment of discontinuity factors. - Abstract: The Laboratory for Reactor Physics and Systems Behaviour at the PSI and the EPFL has been developing in recent years a new code system for reactor analysis based on OpenFOAM®. The objective is to supplement available legacy codes with a modern tool featuring state-of-the-art characteristics in terms of scalability, programming approach and flexibility. As part of this project, a new solver has been developed for the eigenvalue and transient solution of multi-group diffusion equations. Several features distinguish the developed solver from other available codes, in particular: object oriented programming to ease code modification and maintenance; modern parallel computing capabilities; use of general unstructured meshes; possibility of mesh deformation; cell-wise parametrization of cross-sections; and arbitrary energy group structure. In addition, the solver is integrated into the GeN-Foam multi-physics solver. The general features of the solver and its integration with GeN-Foam have already been presented in previous publications. The present paper describes the diffusion solver in more details and provides an overview of new features recently implemented, including the use of acceleration techniques and discontinuity factors. In addition, a code verification is performed through a comparison with Monte Carlo results for both a thermal and a fast reactor system.
Nuclear reactor multi-physics simulations with coupled MCNP5 and STAR-CCM+
International Nuclear Information System (INIS)
Cardoni, Jeffrey Neil; Rizwan-uddin
2011-01-01
The MCNP5 Monte Carlo particle transport code has been coupled to the computational fluid dynamics code, STAR-CCM+, to provide a high fidelity multi-physics simulation tool for pressurized water nuclear reactors. The codes are executed separately and coupled externally through a Perl script. The Perl script automates the exchange of temperature, density, and volumetric heating information between the codes using ASCII text data files. Fortran90 and Java utility programs assist job automation with data post-processing and file management. The MCNP5 utility code, MAKXSF, pre-generates temperature dependent cross section libraries for the thermal feedback calculations. The MCNP5–STAR-CCM+ coupled simulation tool, dubbed MULTINUKE, was applied to a steady state, PWR cell model to demonstrate its usage and capabilities. The demonstration calculation showed reasonable results that agree with PWR values typically reported in literature. Temperature and fission reaction rate distributions were realistic and intuitive. Reactivity coefficients were also deemed reasonable in comparison to historically reported data. The demonstration problem consisted of 9,984 CFD cells and 7,489 neutronic cells. MCNP5 tallied fission energy deposition over 3,328 UO_2 cells. The coupled solution converged within eight hours and in three MULTINUKE iterations. The simulation was carried out on a 64 bit, quad core, Intel 2.8 GHz microprocessor with 1 GB RAM. The simulations on a quad core machine indicated that a massively parallelized implementation of MULTINUKE can be used to assess larger multi-million cell models. (author)
IMPETUS - Interactive MultiPhysics Environment for Unified Simulations.
Ha, Vi Q; Lykotrafitis, George
2016-12-08
We introduce IMPETUS - Interactive MultiPhysics Environment for Unified Simulations, an object oriented, easy-to-use, high performance, C++ program for three-dimensional simulations of complex physical systems that can benefit a large variety of research areas, especially in cell mechanics. The program implements cross-communication between locally interacting particles and continuum models residing in the same physical space while a network facilitates long-range particle interactions. Message Passing Interface is used for inter-processor communication for all simulations. Copyright © 2016 Elsevier Ltd. All rights reserved.
Multi-Physics Analysis of the Fermilab Booster RF Cavity
International Nuclear Information System (INIS)
Awida, M.; Reid, J.; Yakovlev, V.; Lebedev, V.; Khabiboulline, T.; Champion, M.
2012-01-01
After about 40 years of operation the RF accelerating cavities in Fermilab Booster need an upgrade to improve their reliability and to increase the repetition rate in order to support a future experimental program. An increase in the repetition rate from 7 to 15 Hz entails increasing the power dissipation in the RF cavities, their ferrite loaded tuners, and HOM dampers. The increased duty factor requires careful modelling for the RF heating effects in the cavity. A multi-physic analysis investigating both the RF and thermal properties of Booster cavity under various operating conditions is presented in this paper.
Developing a multi-physics solver in APOLLO3 and applications to cross section homogenization
International Nuclear Information System (INIS)
Dugan, Kevin-James
2016-01-01
Multi-physics coupling is becoming of large interest in the nuclear engineering and computational science fields. The ability to obtain accurate solutions to realistic models is important to the design and licensing of novel reactor designs, especially in design basis accident situations. The physical models involved in calculating accident behavior in nuclear reactors includes: neutron transport, thermal conduction/convection, thermo-mechanics in fuel and support structure, fuel stoichiometry, among others. However, this thesis focuses on the coupling between two models, neutron transport and thermal conduction/convection.The goal of this thesis is to develop a multi-physics solver for simulating accidents in nuclear reactors. The focus is both on the simulation environment and the data treatment used in such simulations.This work discusses the development of a multi-physics framework based around the Jacobian-Free Newton-Krylov (JFNK) method. The framework includes linear and nonlinear solvers, along with interfaces to existing numerical codes that solve neutron transport and thermal hydraulics models (APOLLO3 and MCTH respectively) through the computation of residuals. a new formulation for the neutron transport residual is explored, which reduces the solution size and search space by a large factor; instead of the residual being based on the angular flux, it is based on the fission source.The question of whether using a fundamental mode distribution of the neutron flux for cross section homogenization is sufficiently accurate during fast transients is also explored. It is shown that in an infinite homogeneous medium, using homogenized cross sections produced with a fundamental mode flux differ significantly from a reference solution. The error is remedied by using an alternative weighting flux taken from a time dependent calculation; either a time-integrated flux or an asymptotic solution. The time-integrated flux comes from the multi-physics solution of the
SPH based modelling of oxide and oxide film formation in gravity die castings
International Nuclear Information System (INIS)
Ellingsen, K; M'Hamdi, M; Coudert, T
2015-01-01
Gravity die casting is an important casting process which has the capability of making complicated, high-integrity components for e.g. the automotive industry. Oxides and oxide films formed during filling affect the cast product quality. The Smoothed particle hydrodynamics (SPH) method is particularly suited to follow complex flows. The SPH method has been used to study filling of a gravity die including the formation and transport of oxides and oxide films for two different filling velocities. A low inlet velocity leads to a higher amount of oxides and oxide films in the casting. The study demonstrates the usefulness of the SPH method for an increased understanding of the effect of different filling procedures on the cast quality. (paper)
A technique to remove the tensile instability in weakly compressible SPH
Xu, Xiaoyang; Yu, Peng
2018-01-01
When smoothed particle hydrodynamics (SPH) is directly applied for the numerical simulations of transient viscoelastic free surface flows, a numerical problem called tensile instability arises. In this paper, we develop an optimized particle shifting technique to remove the tensile instability in SPH. The basic equations governing free surface flow of an Oldroyd-B fluid are considered, and approximated by an improved SPH scheme. This includes the implementations of the correction of kernel gradient and the introduction of Rusanov flux into the continuity equation. To verify the effectiveness of the optimized particle shifting technique in removing the tensile instability, the impacting drop, the injection molding of a C-shaped cavity, and the extrudate swell, are conducted. The numerical results obtained are compared with those simulated by other numerical methods. A comparison among different numerical techniques (e.g., the artificial stress) to remove the tensile instability is further performed. All numerical results agree well with the available data.
High-Fidelity Space-Time Adaptive Multiphysics Simulations in Nuclear Engineering
Energy Technology Data Exchange (ETDEWEB)
Solin, Pavel [Univ. of Reno, NV (United States); Ragusa, Jean [Texas A & M Univ., College Station, TX (United States)
2014-03-09
We delivered a series of fundamentally new computational technologies that have the potential to significantly advance the state-of-the-art of computer simulations of transient multiphysics nuclear reactor processes. These methods were implemented in the form of a C++ library, and applied to a number of multiphysics coupled problems relevant to nuclear reactor simulations.
High-Fidelity Space-Time Adaptive Multiphysics Simulations in Nuclear Engineering
International Nuclear Information System (INIS)
Solin, Pavel; Ragusa, Jean
2014-01-01
We delivered a series of fundamentally new computational technologies that have the potential to significantly advance the state-of-the-art of computer simulations of transient multiphysics nuclear reactor processes. These methods were implemented in the form of a C++ library, and applied to a number of multiphysics coupled problems relevant to nuclear reactor simulations.
Douillet-Grellier, Thomas; Pramanik, Ranjan; Pan, Kai; Albaiz, Abdulaziz; Jones, Bruce D.; Williams, John R.
2017-10-01
This paper develops a method for imposing stress boundary conditions in smoothed particle hydrodynamics (SPH) with and without the need for dummy particles. SPH has been used for simulating phenomena in a number of fields, such as astrophysics and fluid mechanics. More recently, the method has gained traction as a technique for simulation of deformation and fracture in solids, where the meshless property of SPH can be leveraged to represent arbitrary crack paths. Despite this interest, application of boundary conditions within the SPH framework is typically limited to imposed velocity or displacement using fictitious dummy particles to compensate for the lack of particles beyond the boundary interface. While this is enough for a large variety of problems, especially in the case of fluid flow, for problems in solid mechanics there is a clear need to impose stresses upon boundaries. In addition to this, the use of dummy particles to impose a boundary condition is not always suitable or even feasibly, especially for those problems which include internal boundaries. In order to overcome these difficulties, this paper first presents an improved method for applying stress boundary conditions in SPH with dummy particles. This is then followed by a proposal of a formulation which does not require dummy particles. These techniques are then validated against analytical solutions to two common problems in rock mechanics, the Brazilian test and the penny-shaped crack problem both in 2D and 3D. This study highlights the fact that SPH offers a good level of accuracy to solve these problems and that results are reliable. This validation work serves as a foundation for addressing more complex problems involving plasticity and fracture propagation.
Local Group dSph radio survey with ATCA (III): constraints on particle dark matter
International Nuclear Information System (INIS)
Regis, Marco; Colafrancesco, Sergio; Profumo, Stefano; De Blok, W.J.G.; Massardi, Marcella; Richter, Laura
2014-01-01
We performed a deep search for radio synchrotron emissions induced by weakly interacting massive particles (WIMPs) annihilation or decay in six dwarf spheroidal (dSph) galaxies of the Local Group. Observations were conducted with the Australia Telescope Compact Array (ATCA) at 16 cm wavelength, with an rms sensitivity better than 0.05 mJy/beam in each field. In this work, we first discuss the uncertainties associated with the modeling of the expected signal, such as the shape of the dark matter (DM) profile and the dSph magnetic properties. We then investigate the possibility that point-sources detected in the proximity of the dSph optical center might be due to the emission from a DM cuspy profile. No evidence for an extended emission over a size of few arcmin (which is the DM halo size) has been detected. We present the associated bounds on the WIMP parameter space for different annihilation/decay final states and for different astrophysical assumptions. If the confinement of electrons and positrons in the dSph is such that the majority of their power is radiated within the dSph region, we obtain constraints on the WIMP annihilation rate which are well below the thermal value for masses up to few TeV. On the other hand, for conservative assumptions on the dSph magnetic properties, the bounds can be dramatically relaxed. We show however that, within the next 10 years and regardless of the astrophysical assumptions, it will be possible to progressively close in on the full parameter space of WIMPs by searching for radio signals in dSphs with SKA and its precursors
Local Group dSph radio survey with ATCA (III): constraints on particle dark matter
Energy Technology Data Exchange (ETDEWEB)
Regis, Marco [Dipartimento di Fisica, Università di Torino, via P. Giuria 1, I-10125 Torino (Italy); Colafrancesco, Sergio [School of Physics, University of the Witwatersrand, Johannesburg (South Africa); Profumo, Stefano [Department of Physics, University of California, 1156 High St., Santa Cruz, CA 95064 (United States); De Blok, W.J.G. [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands); Massardi, Marcella [INAF—Istituto di Radioastronomia, Via Gobetti 101, I-40129, Bologna (Italy); Richter, Laura, E-mail: regis@to.infn.it, E-mail: sergio.colafrancesco@wits.ac.za, E-mail: profumo@ucsc.edu, E-mail: blok@astron.nl, E-mail: massardi@ira.inaf.it, E-mail: laura@ska.ac.za [SKA South Africa, 3rd Floor, The Park, Park Road, Pinelands, 7405 (South Africa)
2014-10-01
We performed a deep search for radio synchrotron emissions induced by weakly interacting massive particles (WIMPs) annihilation or decay in six dwarf spheroidal (dSph) galaxies of the Local Group. Observations were conducted with the Australia Telescope Compact Array (ATCA) at 16 cm wavelength, with an rms sensitivity better than 0.05 mJy/beam in each field. In this work, we first discuss the uncertainties associated with the modeling of the expected signal, such as the shape of the dark matter (DM) profile and the dSph magnetic properties. We then investigate the possibility that point-sources detected in the proximity of the dSph optical center might be due to the emission from a DM cuspy profile. No evidence for an extended emission over a size of few arcmin (which is the DM halo size) has been detected. We present the associated bounds on the WIMP parameter space for different annihilation/decay final states and for different astrophysical assumptions. If the confinement of electrons and positrons in the dSph is such that the majority of their power is radiated within the dSph region, we obtain constraints on the WIMP annihilation rate which are well below the thermal value for masses up to few TeV. On the other hand, for conservative assumptions on the dSph magnetic properties, the bounds can be dramatically relaxed. We show however that, within the next 10 years and regardless of the astrophysical assumptions, it will be possible to progressively close in on the full parameter space of WIMPs by searching for radio signals in dSphs with SKA and its precursors.
Feltzing, S.; Eriksson, K.; Kleyna, J.; Wilkinson, M. I.
2009-12-01
Aims. We establish the mean metallicity from high-resolution spectroscopy for the recently found dwarf spheroidal galaxy Boötes I and test whether it is a common feature for ultra-faint dwarf spheroidal galaxies to show signs of inhomogeneous chemical evolution (e.g. as found in the Hercules dwarf spheroidal galaxy). Methods: We analyse high-resolution, moderate signal-to-noise spectra for seven red giant stars in the Boötes I dSph galaxy using standard abundance analysis techniques. In particular, we assume local thermodynamic equilibrium and employ spherical model atmospheres and codes that take the sphericity of the star into account when calculating the elemental abundances. Results: We confirm previous determinations of the mean metallicity of the Boötes I dwarf spheroidal galaxy to be -2.3 dex. Whilst five stars are clustered around this metallicity, one is significantly more metal-poor, at -2.9 dex, and one is more metal-rich at, -1.9 dex. Additionally, we find that one of the stars, Boo-127, shows an atypically high [Mg/Ca] ratio, indicative of stochastic enrichment processes within the dSph galaxy. Similar results have previously only been found in the Hercules and Draco dSph galaxies and appear, so far, to be unique to this type of galaxy. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.
Coupling between a multi-physics workflow engine and an optimization framework
Di Gallo, L.; Reux, C.; Imbeaux, F.; Artaud, J.-F.; Owsiak, M.; Saoutic, B.; Aiello, G.; Bernardi, P.; Ciraolo, G.; Bucalossi, J.; Duchateau, J.-L.; Fausser, C.; Galassi, D.; Hertout, P.; Jaboulay, J.-C.; Li-Puma, A.; Zani, L.
2016-03-01
A generic coupling method between a multi-physics workflow engine and an optimization framework is presented in this paper. The coupling architecture has been developed in order to preserve the integrity of the two frameworks. The objective is to provide the possibility to replace a framework, a workflow or an optimizer by another one without changing the whole coupling procedure or modifying the main content in each framework. The coupling is achieved by using a socket-based communication library for exchanging data between the two frameworks. Among a number of algorithms provided by optimization frameworks, Genetic Algorithms (GAs) have demonstrated their efficiency on single and multiple criteria optimization. Additionally to their robustness, GAs can handle non-valid data which may appear during the optimization. Consequently GAs work on most general cases. A parallelized framework has been developed to reduce the time spent for optimizations and evaluation of large samples. A test has shown a good scaling efficiency of this parallelized framework. This coupling method has been applied to the case of SYCOMORE (SYstem COde for MOdeling tokamak REactor) which is a system code developed in form of a modular workflow for designing magnetic fusion reactors. The coupling of SYCOMORE with the optimization platform URANIE enables design optimization along various figures of merit and constraints.
Experimental Evaluation of Acoustic Engine Liner Models Developed with COMSOL Multiphysics
Schiller, Noah H.; Jones, Michael G.; Bertolucci, Brandon
2017-01-01
Accurate modeling tools are needed to design new engine liners capable of reducing aircraft noise. The purpose of this study is to determine if a commercially-available finite element package, COMSOL Multiphysics, can be used to accurately model a range of different acoustic engine liner designs, and in the process, collect and document a benchmark dataset that can be used in both current and future code evaluation activities. To achieve these goals, a variety of liner samples, ranging from conventional perforate-over-honeycomb to extended-reaction designs, were installed in one wall of the grazing flow impedance tube at the NASA Langley Research Center. The liners were exposed to high sound pressure levels and grazing flow, and the effect of the liner on the sound field in the flow duct was measured. These measurements were then compared with predictions. While this report only includes comparisons for a subset of the configurations, the full database of all measurements and predictions is available in electronic format upon request. The results demonstrate that both conventional perforate-over-honeycomb and extended-reaction liners can be accurately modeled using COMSOL. Therefore, this modeling tool can be used with confidence to supplement the current suite of acoustic propagation codes, and ultimately develop new acoustic engine liners designed to reduce aircraft noise.
Modelling by the SPH method of the impact of a shell containing a fluid
International Nuclear Information System (INIS)
Maurel, B.
2008-01-01
The aim of this work was to develop a numerical simulation tool using a mesh-less approach, able to simulate the deformation and the rupture of thin structures under the impact of a fluid. A model of thick mesh-less shell (Mindlin-Reissner) based on the SPH method has then been carried out. A contact algorithm has moreover been perfected for the interactions between the structure and the fluid, it is modelled too by the SPH method. These studies have been carried out and been included in the CEA Europlexus fast dynamics software. (O.M.)
Huang, Juan; Huang, Kaipeng; Lan, Tian; Xie, Xi; Shen, Xiaoyan; Liu, Peiqing; Huang, Heqing
2013-01-30
Curcumin, a major polyphenol from the golden spice Curcuma longa commonly known as turmeric, has been recently discovered to have renoprotective effects on diabetic nephropathy (DN). However, the mechanisms underlying these effects remain unclear. We previously demonstrated that the sphingosine kinase 1-sphingosine 1-phosphate (SphK1-S1P) signaling pathway plays a pivotal role in the pathogenesis of DN. This study aims to investigate whether the renoprotective effects of curcumin on DN are associated with its inhibitory effects on the SphK1-S1P signaling pathway. Our results demonstrated that the expression and activity of SphK1 and the production of S1P were significantly down-regulated by curcumin in diabetic rat kidneys and glomerular mesangial cells (GMCs) exposed to high glucose (HG). Simultaneously, SphK1-S1P-mediated fibronectin (FN) and transforming growth factor-beta 1 (TGF-β1) overproduction were inhibited. In addition, curcumin dose dependently reduced SphK1 expression and activity in GMCs transfected with SphK(WT) and significantly suppressed the increase in SphK1-mediated FN levels. Furthermore, curcumin inhibited the DNA-binding activity of activator protein 1 (AP-1), and c-Jun small interference RNA (c-Jun-siRNA) reversed the HG-induced up-regulation of SphK1. These findings suggested that down-regulation of the SphK1-S1P pathway is probably a novel mechanism by which curcumin improves the progression of DN. Inhibiting AP-1 activation is one of the therapeutic targets of curcumin to modulate the SphK1-S1P signaling pathway, thereby preventing diabetic renal fibrosis. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
SEREN - a new SPH code for star and planet formation simulations Algorithms and tests
Czech Academy of Sciences Publication Activity Database
Hubber, D.A.; Batty, C.P.; McLeod, Andrew; Whitworth, A.
2011-01-01
Roč. 529, May (2011), A27/1-A27/28 ISSN 0004-6361 Institutional research plan: CEZ:AV0Z10030501 Keywords : hydrodynamics * numerical methods * star s formation Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.587, year: 2011
Johnson, S.; Chiaramonte, L.; Cruz, L.; Izadi, G.
2016-12-01
Advances in the accuracy and fidelity of numerical methods have significantly improved our understanding of coupled processes in unconventional reservoirs. However, such multi-physics models are typically characterized by many parameters and require exceptional computational resources to evaluate systems of practical importance, making these models difficult to use for field analyses or uncertainty quantification. One approach to remove these limitations is through targeted complexity reduction and field data constrained parameterization. For the latter, a variety of field data streams may be available to engineers and asset teams, including micro-seismicity from proximate sites, well logs, and 3D surveys, which can constrain possible states of the reservoir as well as the distributions of parameters. We describe one such workflow, using the Argos multi-physics code and requisite geomechanical analysis to parameterize the underlying models. We illustrate with a field study involving a constraint analysis of various field data and details of the numerical optimizations and model reduction to demonstrate how complex models can be applied to operation design in hydraulic fracturing operations, including selection of controllable completion and fluid injection design properties. The implication of this work is that numerical methods are mature and computationally tractable enough to enable complex engineering analysis and deterministic field estimates and to advance research into stochastic analyses for uncertainty quantification and value of information applications.
Weak Galactic halo-Fornax dSph connection from RR Lyrae stars
Fiorentino, G.; Monelli, M.; Stetson, P. B.; Bono, G.; Gallart, C.; Martínez-Vázquez, C. E.; Bernard, E. J.; Massari, D.; Braga, V. F.; Dall'Ora, M.
2017-01-01
Aims: For the first time accurate pulsation properties of the ancient variable stars of the Fornax dwarf spheroidal galaxy (dSph) are discussed in the broad context of galaxy formation and evolution. Methods: Homogeneous multi-band BVI optical photometry of spanning twenty years has allowed us to
Multi-resolution Delta-plus-SPH with tensile instability control: Towards high Reynolds number flows
Sun, P. N.; Colagrossi, A.; Marrone, S.; Antuono, M.; Zhang, A. M.
2018-03-01
It is well known that the use of SPH models in simulating flow at high Reynolds numbers is limited because of the tensile instability inception in the fluid region characterized by high vorticity and negative pressure. In order to overcome this issue, the δ+-SPH scheme is modified by implementing a Tensile Instability Control (TIC). The latter consists of switching the momentum equation to a non-conservative formulation in the unstable flow regions. The loss of conservation properties is shown to induce small errors, provided that the particle distribution is regular. The latter condition can be ensured thanks to the implementation of a Particle Shifting Technique (PST). The novel variant of the δ+-SPH is proved to be effective in preventing the onset of tensile instability. Several challenging benchmark tests involving flows past bodies at large Reynolds numbers have been used. Within this a simulation characterized by a deforming foil that resembles a fish-like swimming body is used as a practical application of the δ+-SPH model in biological fluid mechanics.
International Nuclear Information System (INIS)
Lazaro, A.; Ordonez, J.; Martorell, S.; Przemyslaw, S.; Ammirabile, L.; Tsige-Tamirat, H.
2015-01-01
The sodium cooled fast reactor (SFR) is one of the reactor types selected by the Generation IV International Forum. SFR stand out due to its remarkable past operational experience in related projects and its potential to achieve the ambitious goals laid for the new generation of nuclear reactors. Regardless its operational experience, there is a need to apply computational tools able to simulate the system behaviour under conditions that may overtake the reactor safety limits from the early stages of the design process, including the three-dimensional phenomena that may arise in these transients. This paper presents the different steps followed towards the development of a multi-physics platform with capabilities to simulate complex phenomena using a coupled neutronic-thermal-hydraulic scheme. The development started with a one-dimensional thermal-hydraulic model of the European Sodium Fast Reactor (ESFR) design with point kinetic neutronic feedback benchmarked with its peers in the framework of the FP7-CP-ESFR project using the state-of-the-art thermal-hydraulic system code TRACE. The model was successively extended into a three-dimensional model coupled with the spatial kinetic neutronic code PARCS able to simulate three-dimensional multi-physic phenomena along with the comparison of the results for symmetric cases. The last part of the paper shows the application of the developed tool to the analysis of transients involving asymmetrical effects, such as the coast-down of a primary and secondary pump or the withdrawal of a peripheral control rod bank, demonstrating the unique capability of the code to simulate such transients and the capability of the design to withstand them under design basis
Multiscale Multiphysics Developments for Accident Tolerant Fuel Concepts
International Nuclear Information System (INIS)
Gamble, K. A.; Hales, J. D.; Yu, J.; Zhang, Y.; Bai, X.; Andersson, D.; Patra, A.; Wen, W.; Tome, C.; Baskes, M.; Martinez, E.; Stanek, C. R.; Miao, Y.; Ye, B.; Hofman, G. L.; Yacout, A. M.; Liu, W.
2015-01-01
U 3 Si 2 and iron-chromium-aluminum (Fe-Cr-Al) alloys are two of many proposed accident-tolerant fuel concepts for the fuel and cladding, respectively. The behavior of these materials under normal operating and accident reactor conditions is not well known. As part of the Department of Energy's Accident Tolerant Fuel High Impact Problem program significant work has been conducted to investigate the U 3 Si 2 and FeCrAl behavior under reactor conditions. This report presents the multiscale and multiphysics effort completed in fiscal year 2015. The report is split into four major categories including Density Functional Theory Developments, Molecular Dynamics Developments, Mesoscale Developments, and Engineering Scale Developments. The work shown here is a compilation of a collaborative effort between Idaho National Laboratory, Los Alamos National Laboratory, Argonne National Laboratory and Anatech Corp.
Induction Heating Process Design Using COMSOL Multiphysics Software
Directory of Open Access Journals (Sweden)
Andy Triwinarko
2011-08-01
Full Text Available Induction heating is clean environmental heating process due to a non-contact heating process. There is lots of the induction heating type that be used in the home appliance but it is still new technology in Indonesia. The main interesting area of the induction heating design is the efficiency of the usage of energy and choice of the plate material. COMSOL Multiphysics Software can be used to simulate and estimate the induction heating process. Therefore, the software can be used to design the induction heating process that will have a optimum efficiency. The properties of the induction heating design were also simulated and analyzed such as effect of inductors width, inductors distance, and conductive plate material. The result was shown that the good design of induction heating must have a short width and distance inductor and used silicon carbide as material plate with high frequency controller.
Multiphysics Numerical Modeling of a Fin and Tube Heat Exchanger
DEFF Research Database (Denmark)
Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph
2015-01-01
In the present research work, a modeling effort to predict the performance of a liquid-gas type fin and tube heat exchanger design is made. Three dimensional (3D) steady state numerical model is developed using commercial software COMSOL Multiphysics based on finite element method (FEM......). For the purposes here, only gas flowing over the fin side is simulated assuming constant inner tube wall temperature. The study couples conjugate heat transfer mechanism with turbulent flow in order to describe the temperature and velocity profile. In addition, performance characteristics of the heat exchanger...... design in terms of heat transfer and pressure loss are determined by parameters such as overall heat transfer coefficient, Colburn j-factor, flow resistance factor, and efficiency index. The model provides useful insights necessary for optimization of heat exchanger design....
Multiphysics modeling of the steel continuous casting process
Hibbeler, Lance C.
This work develops a macroscale, multiphysics model of the continuous casting of steel. The complete model accounts for the turbulent flow and nonuniform distribution of superheat in the molten steel, the elastic-viscoplastic thermal shrinkage of the solidifying shell, the heat transfer through the shell-mold interface with variable gap size, and the thermal distortion of the mold. These models are coupled together with carefully constructed boundary conditions with the aid of reduced-order models into a single tool to investigate behavior in the mold region, for practical applications such as predicting ideal tapers for a beam-blank mold. The thermal and mechanical behaviors of the mold are explored as part of the overall modeling effort, for funnel molds and for beam-blank molds. These models include high geometric detail and reveal temperature variations on the mold-shell interface that may be responsible for cracks in the shell. Specifically, the funnel mold has a column of mold bolts in the middle of the inside-curve region of the funnel that disturbs the uniformity of the hot face temperatures, which combined with the bending effect of the mold on the shell, can lead to longitudinal facial cracks. The shoulder region of the beam-blank mold shows a local hot spot that can be reduced with additional cooling in this region. The distorted shape of the funnel mold narrow face is validated with recent inclinometer measurements from an operating caster. The calculated hot face temperatures and distorted shapes of the mold are transferred into the multiphysics model of the solidifying shell. The boundary conditions for the first iteration of the multiphysics model come from reduced-order models of the process; one such model is derived in this work for mold heat transfer. The reduced-order model relies on the physics of the solution to the one-dimensional heat-conduction equation to maintain the relationships between inputs and outputs of the model. The geometric
Modeling of circulating nuclear fuels with Comsol Multiphysics
International Nuclear Information System (INIS)
Cammi, A.; Di Marcello, V.; Luzzi, L.
2007-01-01
This paper presents multi-physics modelling of circulating nuclear fuel in a simple geometry by means of COMSOL 3.3. Among the Circulating Fuel Reactors (CFR), the most promising is the Molten Salt Reactor (MSR). Physics of such circulating nuclear fuel requires five coupled equations of conservation laws: the momentum balance, the energy balance, the neutron balance and the precursors balance. In this complex field, represented by the coupling of thermal-hydrodynamics with neutronics, the highly non linear regime and the wide disparity of time scales, COMSOL was used to investigate the region of reactor that comprises only the flowing fluid, and a parametric study was performed by varying the size of the analyzed region and the inlet velocity of fluid. This study is sufficient to achieve a preliminary evaluation of the thermo-physical behaviour of the system and paves the way for further progress concerning a more complex and realistic MSR geometry. (authors)
Local Group dSph radio survey with ATCA - II. Non-thermal diffuse emission
Regis, Marco; Richter, Laura; Colafrancesco, Sergio; Profumo, Stefano; de Blok, W. J. G.; Massardi, Marcella
2015-04-01
Our closest neighbours, the Local Group dwarf spheroidal (dSph) galaxies, are extremely quiescent and dim objects, where thermal and non-thermal diffuse emissions lack, so far, of detection. In order to possibly study the dSph interstellar medium, deep observations are required. They could reveal non-thermal emissions associated with the very low level of star formation, or to particle dark matter annihilating or decaying in the dSph halo. In this work, we employ radio observations of six dSphs, conducted with the Australia Telescope Compact Array in the frequency band 1.1-3.1 GHz, to test the presence of a diffuse component over typical scales of few arcmin and at an rms sensitivity below 0.05 mJy beam-1. We observed the dSph fields with both a compact array and long baselines. Short spacings led to a synthesized beam of about 1 arcmin and were used for the extended emission search. The high-resolution data mapped background sources, which in turn were subtracted in the short-baseline maps, to reduce their confusion limit. We found no significant detection of a diffuse radio continuum component. After a detailed discussion on the modelling of the cosmic ray (CR) electron distribution and on the dSph magnetic properties, we present bounds on several physical quantities related to the dSphs, such that the total radio flux, the angular shape of the radio emissivity, the equipartition magnetic field, and the injection and equilibrium distributions of CR electrons. Finally, we discuss the connection to far-infrared and X-ray observations.
A Global Sensitivity Analysis Methodology for Multi-physics Applications
Energy Technology Data Exchange (ETDEWEB)
Tong, C H; Graziani, F R
2007-02-02
Experiments are conducted to draw inferences about an entire ensemble based on a selected number of observations. This applies to both physical experiments as well as computer experiments, the latter of which are performed by running the simulation models at different input configurations and analyzing the output responses. Computer experiments are instrumental in enabling model analyses such as uncertainty quantification and sensitivity analysis. This report focuses on a global sensitivity analysis methodology that relies on a divide-and-conquer strategy and uses intelligent computer experiments. The objective is to assess qualitatively and/or quantitatively how the variabilities of simulation output responses can be accounted for by input variabilities. We address global sensitivity analysis in three aspects: methodology, sampling/analysis strategies, and an implementation framework. The methodology consists of three major steps: (1) construct credible input ranges; (2) perform a parameter screening study; and (3) perform a quantitative sensitivity analysis on a reduced set of parameters. Once identified, research effort should be directed to the most sensitive parameters to reduce their uncertainty bounds. This process is repeated with tightened uncertainty bounds for the sensitive parameters until the output uncertainties become acceptable. To accommodate the needs of multi-physics application, this methodology should be recursively applied to individual physics modules. The methodology is also distinguished by an efficient technique for computing parameter interactions. Details for each step will be given using simple examples. Numerical results on large scale multi-physics applications will be available in another report. Computational techniques targeted for this methodology have been implemented in a software package called PSUADE.
International Nuclear Information System (INIS)
Chauliac, Christian; Bestion, Dominique; Crouzet, Nicolas; Aragones, Jose-Maria; Cacuci, Dan Gabriel; Weiss, Frank-Peter; Zimmermann, Martin A.
2010-01-01
The NURESIM project, the numerical simulation platform, is developed in the frame of the NURISP European Collaborative Project (FP7), which includes 22 organizations from 14 European countries. NURESIM intends to be a reference platform providing high quality software tools, physical models, generic functions and assessment results. The NURESIM platform provides an accurate representation of the physical phenomena by promoting and incorporating the latest advances in core physics, two-phase thermal-hydraulics and fuel modelling. It includes multi-scale and multi-physics features, especially for coupling core physics and thermal-hydraulics models for reactor safety. Easy coupling of the different codes and solvers is provided through the use of a common data structure and generic functions (e.g., for interpolation between non-conforming meshes). More generally, the platform includes generic pre-processing, post-processing and supervision functions through the open-source SALOME software, in order to make the codes more user-friendly. The platform also provides the informatics environment for testing and comparing different codes. The contribution summarizes the achievements and ongoing developments of the simulation platform in core physics, thermal-hydraulics, multi-physics, uncertainties and code integration
The Data Transfer Kit: A geometric rendezvous-based tool for multiphysics data transfer
International Nuclear Information System (INIS)
Slattery, S. R.; Wilson, P. P. H.; Pawlowski, R. P.
2013-01-01
The Data Transfer Kit (DTK) is a software library designed to provide parallel data transfer services for arbitrary physics components based on the concept of geometric rendezvous. The rendezvous algorithm provides a means to geometrically correlate two geometric domains that may be arbitrarily decomposed in a parallel simulation. By repartitioning both domains such that they have the same geometric domain on each parallel process, efficient and load balanced search operations and data transfer can be performed at a desirable algorithmic time complexity with low communication overhead relative to other types of mapping algorithms. With the increased development efforts in multiphysics simulation and other multiple mesh and geometry problems, generating parallel topology maps for transferring fields and other data between geometric domains is a common operation. The algorithms used to generate parallel topology maps based on the concept of geometric rendezvous as implemented in DTK are described with an example using a conjugate heat transfer calculation and thermal coupling with a neutronics code. In addition, we provide the results of initial scaling studies performed on the Jaguar Cray XK6 system at Oak Ridge National Laboratory for a worse-case-scenario problem in terms of algorithmic complexity that shows good scaling on 0(1 x 104) cores for topology map generation and excellent scaling on 0(1 x 105) cores for the data transfer operation with meshes of O(1 x 109) elements. (authors)
International Nuclear Information System (INIS)
Liu Rong; Zhou Wenzhong; Prudil, Andrew
2015-01-01
This paper presents the development of a light water reactor fuel performance code, which considers almost all the related physical models, including heat generation and conduction, species diffusion, thermomechanics (thermal expansion, elastic strain, densification, and fission product swelling strain), grain growth, fission gas production and release, gap heat transfer, mechanical contact, gap/plenum pressure with plenum volume, cladding thermal and irradiation creep and oxidation. All the equations are implemented into COMSOL Multiphysics finite-element platform with a 2D axisymmetric geometry of a fuel pellet and cladding. Comparisons are made for the simulation results between COMSOL and another simulation tool of BISON. The comparisons show the capability of our simulation tool to predict light water UO 2 fuel performances. In our modeling and simulation work, the performance of enhanced thermal conductivity UO 2 -BeO fuel and newly-adopted corrosion resistant SiC cladding material was also studied. UO 2 -BeO high thermal conductivity nuclear fuel would decrease fuel temperatures and facilitate a reduction in pellet cladding interaction through lessening thermal stresses that result in fuel cracking, relocation, and swelling. The safety of the reactor would be improved. However, for SiC cladding, although due to its high thermal expansion, the gap closure time is delayed, irradiation induced point defects and defect-clusters in the SiC crystal will dramatically decrease SiC thermal conductivity, and cause significant increase in the fuel temperature. (author)
International Nuclear Information System (INIS)
Gaston, Derek; Guo, Luanjing; Hansen, Glen; Huang, Hai; Johnson, Richard; Park, HyeongKae; Podgorney, Robert; Tonks, Michael; Williamson, Richard
2012-01-01
There is a growing trend within energy and environmental simulation to consider tightly coupled solutions to multiphysics problems. This can be seen in nuclear reactor analysis where analysts are interested in coupled flow, heat transfer and neutronics, and in nuclear fuel performance simulation where analysts are interested in thermomechanics with contact coupled to species transport and chemistry. In energy and environmental applications, energy extraction involves geomechanics, flow through porous media and fractured formations, adding heat transport for enhanced oil recovery and geothermal applications, and adding reactive transport in the case of applications modeling the underground flow of contaminants. These more ambitious simulations usually motivate some level of parallel computing. Many of the physics coupling efforts to date utilize simple code coupling or first-order operator splitting, often referred to as loose coupling. While these approaches can produce answers, they usually leave questions of accuracy and stability unanswered. Additionally, the different physics often reside on distinct meshes and data are coupled via simple interpolation, again leaving open questions of stability and accuracy.
The Data Transfer Kit: A geometric rendezvous-based tool for multiphysics data transfer
Energy Technology Data Exchange (ETDEWEB)
Slattery, S. R.; Wilson, P. P. H. [Department of Engineering Physics, University of Wisconsin - Madison, 1500 Engineering Dr., Madison, WI 53706 (United States); Pawlowski, R. P. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States)
2013-07-01
The Data Transfer Kit (DTK) is a software library designed to provide parallel data transfer services for arbitrary physics components based on the concept of geometric rendezvous. The rendezvous algorithm provides a means to geometrically correlate two geometric domains that may be arbitrarily decomposed in a parallel simulation. By repartitioning both domains such that they have the same geometric domain on each parallel process, efficient and load balanced search operations and data transfer can be performed at a desirable algorithmic time complexity with low communication overhead relative to other types of mapping algorithms. With the increased development efforts in multiphysics simulation and other multiple mesh and geometry problems, generating parallel topology maps for transferring fields and other data between geometric domains is a common operation. The algorithms used to generate parallel topology maps based on the concept of geometric rendezvous as implemented in DTK are described with an example using a conjugate heat transfer calculation and thermal coupling with a neutronics code. In addition, we provide the results of initial scaling studies performed on the Jaguar Cray XK6 system at Oak Ridge National Laboratory for a worse-case-scenario problem in terms of algorithmic complexity that shows good scaling on 0(1 x 104) cores for topology map generation and excellent scaling on 0(1 x 105) cores for the data transfer operation with meshes of O(1 x 109) elements. (authors)
Sensitivity analysis of VERA-CS and FRAPCON coupling in a multiphysics environment
International Nuclear Information System (INIS)
Blakely, Cole; Zhang, Hongbin; Ban, Heng
2018-01-01
Highlights: •VERA-CS and FRAPCON coupling. •Uncertainty quantification and sensitivity analysis for coupled VERA-CS and FRAPCON simulations in a multiphysics environment LOTUS. -- Abstract: A demonstration and description of the LOCA Toolkit for US light water reactors (LOTUS) is presented. Through LOTUS, the core simulator VERA-CS developed by CASL is coupled with the fuel performance code FRAPCON. The coupling is performed with consistent uncertainty propagation with all model inconsistencies being well-documented. Monte Carlo sampling is performed on a single 17 × 17 fuel assembly with a three cycle depletion case. Both uncertainty quantification (UQ) and sensitivity analysis (SA) are used at multiple states within the simulation to elucidate the behavior of minimum departure from nucleate boiling ratio (MDNBR), maximum fuel centerline temperature (MFCT), and gap conductance at peak power (GCPP). The SA metrics used are the Pearson correlation coefficient, Sobol sensitivity indices, and the density-based, delta moment independent measures. Results for MDNBR show consistency among all SA measures, as well for all states throughout the fuel lifecycle. MFCT results contain consistent rankings between SA measures, but show differences throughout the lifecycle. GCPP exhibits predominantly linear relations at low and high burnup, but highly nonlinear relations at intermediate burnup due to abrupt shifts between models. Such behavior is largely undetectable to traditional regression or variance-based methods and demonstrates the utility of density-based methods.
An integrated multiphysics model for friction stir welding of 6061 Aluminum alloy
Directory of Open Access Journals (Sweden)
M Nourani
2016-09-01
Full Text Available This article presents a new, combined ‘integrated’- ‘multiphysics’ model of friction stir welding (FSW where a set of governing equations from non-Newtonian incompressible fluid dynamics, conductive and convective heat transfer, and plain stress solid mechanics have been coupled for calculating the process variables and material behaviour both during and after welding. More specifically, regarding the multiphysics feature, the model is capable of simultaneously predicting the local distribution, location and magnitude of maximum temperature, strain, and strain rate fields around the tool pin during the process; while for the integrated (post-analysis part, the above predictions have been used to study the microstructure and residual stress field of welded parts within the same developed code. A slip/stick condition between the tool and workpiece, friction and deformation heat source, convection and conduction heat transfer in the workpiece, a solid mechanics-based viscosity definition, and the Zener-Hollomon- based rigid-viscoplastic material properties with solidus cut-off temperature and empirical softening regime have been employed. In order to validate all the predicted variables collectively, the model has been compared to a series of published case studies on individual/limited set of variables, as well as in-house experiments on FSW of aluminum 6061.
Coupling a Basin Modeling and a Seismic Code using MOAB
Yan, Mi; Jordan, Kirk; Kaushik, Dinesh; Perrone, Michael; Sachdeva, Vipin; Tautges, Timothy J.; Magerlein, John
2012-01-01
We report on a demonstration of loose multiphysics coupling between a basin modeling code and a seismic code running on a large parallel machine. Multiphysics coupling, which is one critical capability for a high performance computing (HPC) framework, was implemented using the MOAB open-source mesh and field database. MOAB provides for code coupling by storing mesh data and input and output field data for the coupled analysis codes and interpolating the field values between different meshes used by the coupled codes. We found it straightforward to use MOAB to couple the PBSM basin modeling code and the FWI3D seismic code on an IBM Blue Gene/P system. We describe how the coupling was implemented and present benchmarking results for up to 8 racks of Blue Gene/P with 8192 nodes and MPI processes. The coupling code is fast compared to the analysis codes and it scales well up to at least 8192 nodes, indicating that a mesh and field database is an efficient way to implement loose multiphysics coupling for large parallel machines.
Coupling a Basin Modeling and a Seismic Code using MOAB
Yan, Mi
2012-06-02
We report on a demonstration of loose multiphysics coupling between a basin modeling code and a seismic code running on a large parallel machine. Multiphysics coupling, which is one critical capability for a high performance computing (HPC) framework, was implemented using the MOAB open-source mesh and field database. MOAB provides for code coupling by storing mesh data and input and output field data for the coupled analysis codes and interpolating the field values between different meshes used by the coupled codes. We found it straightforward to use MOAB to couple the PBSM basin modeling code and the FWI3D seismic code on an IBM Blue Gene/P system. We describe how the coupling was implemented and present benchmarking results for up to 8 racks of Blue Gene/P with 8192 nodes and MPI processes. The coupling code is fast compared to the analysis codes and it scales well up to at least 8192 nodes, indicating that a mesh and field database is an efficient way to implement loose multiphysics coupling for large parallel machines.
Lithium-Ion Battery Safety Study Using Multi-Physics Internal Short-Circuit Model (Presentation)
Energy Technology Data Exchange (ETDEWEB)
Kim, G-.H.; Smith, K.; Pesaran, A.
2009-06-01
This presentation outlines NREL's multi-physics simulation study to characterize an internal short by linking and integrating electrochemical cell, electro-thermal, and abuse reaction kinetics models.
Multiphysics simulation of thermal phenomena in direct laser metal powder deposition
CSIR Research Space (South Africa)
Pityana, SL
2016-11-01
Full Text Available presents on two dimensional multi-physics models to describe the physical mechanism of heat transfer, melting and solidification that take place during and post laser-powder interaction. The simulated transient temperature profile, the geometrical features...
Energy Technology Data Exchange (ETDEWEB)
Jo, Young Beom; Kim, Eung Soo [Seoul National Univ., Seoul (Korea, Republic of)
2014-10-15
It becomes more complicated when considering the shape and phase of the ground below the seawater. Therefore, some different attempts are required to precisely analyze the behavior of tsunami. This paper introduces an on-going activities on code development in SNU based on an unconventional mesh-free fluid analysis method called Smoothed Particle Hydrodynamics (SPH) and its verification work with some practice simulations. This paper summarizes the on-going development and verification activities on Lagrangian mesh-free SPH code in SNU. The newly developed code can cover equation of motions and heat conduction equation so far, and verification of each models is completed. In addition, parallel computation using GPU is now possible, and GUI is also prepared. If users change input geometry or input values, they can simulate for various conditions geometries. A SPH method has large advantages and potential in modeling of free surface, highly deformable geometry and multi-phase problems that traditional grid-based code has difficulties in analysis. Therefore, by incorporating more complex physical models such as turbulent flow, phase change, two-phase flow, and even solid mechanics, application of the current SPH code is expected to be much more extended including molten fuel behaviors in the sever accident.
Multidimensional, multiphysics simulations of core-collapse supernovae
Energy Technology Data Exchange (ETDEWEB)
Messer, O E B [National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6008 (United States); Bruenn, S W [Department of Physics, Florida Atlantic University, Boca Raton, FL 33431-0991 (United States); Blondin, J M [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Hix, W R; Mezzacappa, A [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6354 (United States)
2008-07-15
CHIMERA is a multi-dimensional radiation hydrodynamics code designed to study core-collapse supernovae. The code is made up of three essentially independent parts: a hydrodynamics module, a nuclear burning module, and a neutrino transport solver combined within an operator-split approach. We review the code's architecture and some recently improved implementations used in the code. We also briefly discuss preliminary results obtained with the code in three spatial dimensions.
Energy Technology Data Exchange (ETDEWEB)
Donald Estep; Michael Holst; Simon Tavener
2010-02-08
This project was concerned with the accurate computational error estimation for numerical solutions of multiphysics, multiscale systems that couple different physical processes acting across a large range of scales relevant to the interests of the DOE. Multiscale, multiphysics models are characterized by intimate interactions between different physics across a wide range of scales. This poses significant computational challenges addressed by the proposal, including: (1) Accurate and efficient computation; (2) Complex stability; and (3) Linking different physics. The research in this project focused on Multiscale Operator Decomposition methods for solving multiphysics problems. The general approach is to decompose a multiphysics problem into components involving simpler physics over a relatively limited range of scales, and then to seek the solution of the entire system through some sort of iterative procedure involving solutions of the individual components. MOD is a very widely used technique for solving multiphysics, multiscale problems; it is heavily used throughout the DOE computational landscape. This project made a major advance in the analysis of the solution of multiscale, multiphysics problems.
Lee, Gileung; Lee, Kang-Ie; Lee, Yunjoo; Kim, Backki; Lee, Dongryung; Seo, Jeonghwan; Jang, Su; Chin, Joong Hyoun; Koh, Hee-Jong
2018-07-01
The split-hull phenotype caused by reduced lemma width and low lignin content is under control of SPH encoding a type-2 13-lipoxygenase and contributes to high dehulling efficiency. Rice hulls consist of two bract-like structures, the lemma and palea. The hull is an important organ that helps to protect seeds from environmental stress, determines seed shape, and ensures grain filling. Achieving optimal hull size and morphology is beneficial for seed development. We characterized the split-hull (sph) mutant in rice, which exhibits hull splitting in the interlocking part between lemma and palea and/or the folded part of the lemma during the grain filling stage. Morphological and chemical analysis revealed that reduction in the width of the lemma and lignin content of the hull in the sph mutant might be the cause of hull splitting. Genetic analysis indicated that the mutant phenotype was controlled by a single recessive gene, sph (Os04g0447100), which encodes a type-2 13-lipoxygenase. SPH knockout and knockdown transgenic plants displayed the same split-hull phenotype as in the mutant. The sph mutant showed significantly higher linoleic and linolenic acid (substrates of lipoxygenase) contents in spikelets compared to the wild type. It is probably due to the genetic defect of SPH and subsequent decrease in lipoxygenase activity. In dehulling experiment, the sph mutant showed high dehulling efficiency even by a weak tearing force in a dehulling machine. Collectively, the results provide a basis for understanding of the functional role of lipoxygenase in structure and maintenance of hulls, and would facilitate breeding of easy-dehulling rice.
Multiscale Multiphysics and Multidomain Models I: Basic Theory.
Wei, Guo-Wei
2013-12-01
This work extends our earlier two-domain formulation of a differential geometry based multiscale paradigm into a multidomain theory, which endows us the ability to simultaneously accommodate multiphysical descriptions of aqueous chemical, physical and biological systems, such as fuel cells, solar cells, nanofluidics, ion channels, viruses, RNA polymerases, molecular motors and large macromolecular complexes. The essential idea is to make use of the differential geometry theory of surfaces as a natural means to geometrically separate the macroscopic domain of solvent from the microscopic domain of solute, and dynamically couple continuum and discrete descriptions. Our main strategy is to construct energy functionals to put on an equal footing of multiphysics, including polar (i.e., electrostatic) solvation, nonpolar solvation, chemical potential, quantum mechanics, fluid mechanics, molecular mechanics, coarse grained dynamics and elastic dynamics. The variational principle is applied to the energy functionals to derive desirable governing equations, such as multidomain Laplace-Beltrami (LB) equations for macromolecular morphologies, multidomain Poisson-Boltzmann (PB) equation or Poisson equation for electrostatic potential, generalized Nernst-Planck (NP) equations for the dynamics of charged solvent species, generalized Navier-Stokes (NS) equation for fluid dynamics, generalized Newton's equations for molecular dynamics (MD) or coarse-grained dynamics and equation of motion for elastic dynamics. Unlike the classical PB equation, our PB equation is an integral-differential equation due to solvent-solute interactions. To illustrate the proposed formalism, we have explicitly constructed three models, a multidomain solvation model, a multidomain charge transport model and a multidomain chemo-electro-fluid-MD-elastic model. Each solute domain is equipped with distinct surface tension, pressure, dielectric function, and charge density distribution. In addition to long
Multiscale multiphysics and multidomain models—Flexibility and rigidity
International Nuclear Information System (INIS)
Xia, Kelin; Opron, Kristopher; Wei, Guo-Wei
2013-01-01
The emerging complexity of large macromolecules has led to challenges in their full scale theoretical description and computer simulation. Multiscale multiphysics and multidomain models have been introduced to reduce the number of degrees of freedom while maintaining modeling accuracy and achieving computational efficiency. A total energy functional is constructed to put energies for polar and nonpolar solvation, chemical potential, fluid flow, molecular mechanics, and elastic dynamics on an equal footing. The variational principle is utilized to derive coupled governing equations for the above mentioned multiphysical descriptions. Among these governing equations is the Poisson-Boltzmann equation which describes continuum electrostatics with atomic charges. The present work introduces the theory of continuum elasticity with atomic rigidity (CEWAR). The essence of CEWAR is to formulate the shear modulus as a continuous function of atomic rigidity. As a result, the dynamics complexity of a macromolecular system is separated from its static complexity so that the more time-consuming dynamics is handled with continuum elasticity theory, while the less time-consuming static analysis is pursued with atomic approaches. We propose a simple method, flexibility-rigidity index (FRI), to analyze macromolecular flexibility and rigidity in atomic detail. The construction of FRI relies on the fundamental assumption that protein functions, such as flexibility, rigidity, and energy, are entirely determined by the structure of the protein and its environment, although the structure is in turn determined by all the interactions. As such, the FRI measures the topological connectivity of protein atoms or residues and characterizes the geometric compactness of the protein structure. As a consequence, the FRI does not resort to the interaction Hamiltonian and bypasses matrix diagonalization, which underpins most other flexibility analysis methods. FRI's computational complexity is of O
Au _{38} (SPh) _{24} : Au _{38} Protected with Aromatic Thiolate Ligands
Energy Technology Data Exchange (ETDEWEB)
Rambukwella, Milan; Burrage, Shayna; Neubrander, Marie; Baseggio, Oscar; Aprà, Edoardo; Stener, Mauro; Fortunelli, Alessandro; Dass, Amala
2017-03-21
Au38(SR)24 is one of the most extensively investigated gold nanomolecules along with Au25(SR)18 and Au144(SR)60. However, so far it has only been prepared using aliphatic-like ligands, where R = –SC6H13, -SC12H25 and –SCH2CH2Ph. Au38(SCH2CH2Ph)24 when reacted with HSPh undergoes core-size conversion to Au36(SPh)24, and existing literature suggest that Au38(SPh)24 cannot be synthesized. Here, contrary to prevailing knowledge, we demonstrate that Au38(SPh)24 can be prepared if the ligand exchanged conditions are optimized, without any formation of Au36(SPh)24. Conclusive evidence is presented in the form of MALDI-MS, ESI-MS characterization, and optical spectra of Au38(SPh)24 in a solid glass form showing distinct differences from that of Au38(S-aliphatic)24. Theoretical analysis confirms experimental assignment of the optical spectrum and shows that the stability of Au38(SPh)24 is comparable to that of its aliphatic analogues, but results from different physical origins, with a significant component of ligand-ligand attractive interactions.
Dark matter in the Reticulum II dSph: a radio search
Regis, Marco; Richter, Laura; Colafrancesco, Sergio
2017-07-01
We present a deep radio search in the Reticulum II dwarf spheroidal (dSph) galaxy performed with the Australia Telescope Compact Array. Observations were conducted at 16 cm wavelength, with an rms sensitivity of 0.01 mJy/beam, and with the goal of searching for synchrotron emission induced by annihilation or decay of weakly interacting massive particles (WIMPs). Data were complemented with observations on large angular scales taken with the KAT-7 telescope. We find no evidence for a diffuse emission from the dSph and we derive competitive bounds on the WIMP properties. In addition, we detect more than 200 new background radio sources. Among them, we show there are two compelling candidates for being the radio counterpart of the possible γ-ray emission reported by other groups using Fermi-LAT data.
Dark matter in the Reticulum II dSph: a radio search
International Nuclear Information System (INIS)
Regis, Marco; Richter, Laura; Colafrancesco, Sergio
2017-01-01
We present a deep radio search in the Reticulum II dwarf spheroidal (dSph) galaxy performed with the Australia Telescope Compact Array. Observations were conducted at 16 cm wavelength, with an rms sensitivity of 0.01 mJy/beam, and with the goal of searching for synchrotron emission induced by annihilation or decay of weakly interacting massive particles (WIMPs). Data were complemented with observations on large angular scales taken with the KAT-7 telescope. We find no evidence for a diffuse emission from the dSph and we derive competitive bounds on the WIMP properties. In addition, we detect more than 200 new background radio sources. Among them, we show there are two compelling candidates for being the radio counterpart of the possible γ-ray emission reported by other groups using Fermi-LAT data.
A Modified SPH Method for Dynamic Failure Simulation of Heterogeneous Material
Directory of Open Access Journals (Sweden)
G. W. Ma
2014-01-01
Full Text Available A modified smoothed particle hydrodynamics (SPH method is applied to simulate the failure process of heterogeneous materials. An elastoplastic damage model based on an extension form of the unified twin shear strength (UTSS criterion is adopted. Polycrystalline modeling is introduced to generate the artificial microstructure of specimen for the dynamic simulation of Brazilian splitting test and uniaxial compression test. The strain rate effect on the predicted dynamic tensile and compressive strength is discussed. The final failure patterns and the dynamic strength increments demonstrate good agreements with experimental results. It is illustrated that the polycrystalline modeling approach combined with the SPH method is promising to simulate more complex failure process of heterogeneous materials.
Programme de soutien à l'interaction avec la sphère des politiques ...
International Development Research Centre (IDRC) Digital Library (Canada)
Programme de soutien à l'interaction avec la sphère des politiques et à la communication de l'Initiative Think tank. Les think tanks des pays en développement entendent effectuer des recherches de qualité fondées sur des données probantes pour contribuer à la résolution d'enjeux en matière de politiques dans les pays ...
Development of a two-phase SPH model for sediment laden flows
Shi, Huabin; Yu, Xiping; Dalrymple, Robert A.
2017-12-01
A SPH model based on a general formulation for solid-fluid two-phase flows is proposed for suspended sediment motion in free surface flows. The water and the sediment are treated as two miscible fluids, and the multi-fluid system is discretized by a single set of SPH particles, which move with the water velocity and carry properties of the two phases. Large eddy simulation (LES) is introduced to deal with the turbulence effect, and the widely used Smagorinsky model is modified to take into account the influence of sediment particles on the turbulence. The drag force is accurately formulated by including the hindered settling effect. In the model, the water is assumed to be weakly compressible while the sediment is incompressible, and a new equation of state is proposed for the pressure in the sediment-water mixture. Dynamic boundary condition is employed to treat wall boundaries, and a new strategy of Shepard filtering is adopted to damp the pressure oscillation. The developed two-phase SPH model is validated by comparing the numerical results with analytical solutions for idealized cases of still water containing both neutrally buoyant and naturally settling sand and for plane Poiseuille flows carrying neutrally buoyant particles, and is then applied to sand dumping from a line source into a water tank, where the sand cloud settles with a response of the free water surface. It is shown that the numerical results are in good agreement with the experimental data as well as the empirical formulas. The characteristics of the settling sand cloud, the pressure field, and the flow vortices are studied. The motion of the free water surface is also discussed. The proposed two-phase SPH model is proven to be effective for numerical simulation of sand dumping into waters.
Culture et exercice du pouvoir par les femmes dans les sphères de ...
International Development Research Centre (IDRC) Digital Library (Canada)
Culture et exercice du pouvoir par les femmes dans les sphères de décisions en Afrique de l'Ouest. Cette recherche s'inscrit dans le contexte d'une superposition de deux faits : l'existence d'un arsenal juridique et de dispositions nationales et internationales favorables à une intégration des femmes dans les instances de ...
Energy Technology Data Exchange (ETDEWEB)
Debord, R
1999-07-01
The aim of this study is the modeling of the impact of melted metal on the reactor vessel head in the case of a core-meltdown accident. Modeling using the classical finite-element method alone is not sufficient but requires a coupling with particulate methods in order to take into account the behaviour of the corium. After a general introduction about particulate methods, the Nabor and SPH (smoothed particle hydrodynamics) methods are described. Then, the theoretical and numerical reliability of the SPH method is determined using simple cases. In particular, the number of neighbours significantly influences the preciseness of calculations. Also, the mesh of the structure must be adapted to the mesh of the fluid in order to reduce the edge effects. Finally, this study has shown that the values of artificial velocity coefficients used in the simulation of the BERDA test performed by the FZK Karlsruhe (Germany) are not correct. The domain of use of these coefficients was precised during a low speed impact. (J.S.)
Energy Technology Data Exchange (ETDEWEB)
Debord, R
1999-07-01
The aim of this study is the modeling of the impact of melted metal on the reactor vessel head in the case of a core-meltdown accident. Modeling using the classical finite-element method alone is not sufficient but requires a coupling with particulate methods in order to take into account the behaviour of the corium. After a general introduction about particulate methods, the Nabor and SPH (smoothed particle hydrodynamics) methods are described. Then, the theoretical and numerical reliability of the SPH method is determined using simple cases. In particular, the number of neighbours significantly influences the preciseness of calculations. Also, the mesh of the structure must be adapted to the mesh of the fluid in order to reduce the edge effects. Finally, this study has shown that the values of artificial velocity coefficients used in the simulation of the BERDA test performed by the FZK Karlsruhe (Germany) are not correct. The domain of use of these coefficients was precised during a low speed impact. (J.S.)
Design Process of IDT Aided by Multiphysics FE Analyses
Directory of Open Access Journals (Sweden)
A Martowicz
2016-09-01
Full Text Available Presented work is devoted to a design process performed for the interdigital transducer, which is a perspective application for the area of structural health monitoring. In order to obtain the desirable characteristic of the transducer fully coupled numerical analyses were performed in ANSYS Multiphysics software. Utilised finite element models considered both structural dynamics and properties of used piezoelectric material. The process of design improvement was preceded by the sensitivity analysis. In order to search for the best electrode pattern selected geometrical features of the transducer were assumed to vary within allowed ranges. The design parameters, which were taken into account, related to the efficiency of proposed transducer design for the emission of acoustic waves in the monitored structure. The search objectives considered the criteria related to the shape of the beampattern and amplitudes of generated Lamb waves. As a result of the optimization procedure, the simultaneous increase of anti-symmetric mode amplitude and the reduction of undesirable symmetric mode amplitude of generated Lamb waves in the direction perpendicular to the transducer fingers was expected. Another aim of the optimization was to minimize the main lobe width and undesirable contribution of both symmetric and anti-symmetric waves in the parallel direction to the transducer fingers. The response surface method and genetic algorithms were used for fast and effective search through the input design domain.
Exploring a Multiphysics Resolution Approach for Additive Manufacturing
Estupinan Donoso, Alvaro Antonio; Peters, Bernhard
2018-06-01
Metal additive manufacturing (AM) is a fast-evolving technology aiming to efficiently produce complex parts while saving resources. Worldwide, active research is being performed to solve the existing challenges of this growing technique. Constant computational advances have enabled multiscale and multiphysics numerical tools that complement the traditional physical experimentation. In this contribution, an advanced discrete-continuous concept is proposed to address the physical phenomena involved during laser powder bed fusion. The concept treats powder as discrete by the extended discrete element method, which predicts the thermodynamic state and phase change for each particle. The fluid surrounding is solved with multiphase computational fluid dynamics techniques to determine momentum, heat, gas and liquid transfer. Thus, results track the positions and thermochemical history of individual particles in conjunction with the prevailing fluid phases' temperature and composition. It is believed that this methodology can be employed to complement experimental research by analysis of the comprehensive results, which can be extracted from it to enable AM processes optimization for parts qualification.
Curing of Thick Thermoset Composite Laminates: Multiphysics Modeling and Experiments
Anandan, S.; Dhaliwal, G. S.; Huo, Z.; Chandrashekhara, K.; Apetre, N.; Iyyer, N.
2017-11-01
Fiber reinforced polymer composites are used in high-performance aerospace applications as they are resistant to fatigue, corrosion free and possess high specific strength. The mechanical properties of these composite components depend on the degree of cure and residual stresses developed during the curing process. While these parameters are difficult to determine experimentally in large and complex parts, they can be simulated using numerical models in a cost-effective manner. These simulations can be used to develop cure cycles and change processing parameters to obtain high-quality parts. In the current work, a numerical model was built in Comsol MultiPhysics to simulate the cure behavior of a carbon/epoxy prepreg system (IM7/Cycom 5320-1). A thermal spike was observed in thick laminates when the recommended cure cycle was used. The cure cycle was modified to reduce the thermal spike and maintain the degree of cure at the laminate center. A parametric study was performed to evaluate the effect of air flow in the oven, post cure cycles and cure temperatures on the thermal spike and the resultant degree of cure in the laminate.
Vanaverbeke, S.; Keppens, R.; Poedts, S.; Boffin, H.
2009-01-01
We describe the algorithms implemented in the first version of GRADSPH, a parallel, tree-based, smoothed particle hydrodynamics code for simulating self-gravitating astrophysical systems written in FORTRAN 90. The paper presents details on the implementation of the Smoothed Particle Hydro (SPH)
Eichhöfer, Andreas; Buth, Gernot
2016-11-01
Reactions of [Co(N(SiMe 3 ) 2 ) 2 thf] with 2.1 equiv. of MesSH (Mes = C 6 H 2 -2,4,6-(CH 3 ) 3 ) yield dark brown crystals of the one dimensional chain compound [Co(SMes) 2 ]. In contrast reactions of [Co(N(SiMe 3 ) 2 ) 2 thf] with 2.1 equiv. of PhSH result in the formation of a dark brown almost X-ray amorphous powder of 'Co(SPh) 2 '. Addition of aliquots of CH 3 OH to the latter reaction resulted in the almost quantitative formation of crystalline ammonia thiolato complexes either [Co(SPh) 2 (NH 3 ) 2 ] or [Co(SPh) 2 NH 3 ]. Single crystal XRD reveals that [Co(SPh) 2 NH 3 ] forms one-dimensional chains in the crystal via μ 2 -SPh bridges whereas [Co(SPh) 2 (NH 3 ) 2 ] consists at a first glance of isolated distorted tetrahedral units. Magnetic measurements suggest strong antiferromagnetic coupling for the two chain compounds [Co(SMes) 2 ] (J = -38.6 cm -1 ) and [Co(SPh) 2 NH 3 ] (J = -27.1 cm -1 ). Interestingly, also the temperature dependence of the susceptibility of tetrahedral [Co(SPh) 2 (NH 3 ) 2 ] shows an antiferromagnetic transition at around 6 K. UV-Vis-NIR spectra display d-d bands in the NIR region between 500 and 2250 nm. Thermal gravimetric analysis of [Co(SPh) 2 (NH 3 ) 2 ] and [Co(SPh) 2 NH 3 ] reveals two well separated cleavage processes for NH 3 and SPh 2 upon heating accompanied by the stepwise formation of 'Co(SPh) 2 ' and cobalt sulfide.
The APOLLO assembly spectrum code
International Nuclear Information System (INIS)
Kavenoky, A.; Sanchez, R.
1987-04-01
The APOLLO code was originally developed as a design tool for HTR's, later it was aimed at the calculation of PWR lattices. APOLLO is a general purpose assembly spectrum code based on the multigroup integral transport equation; refined collision probability modules allow the computation of 1D geometries with linearly anisotropic scattering and two term flux expansion. In 2D geometries modules based on the substructure method provide fast and accurate design calculations and a module based on a direct discretization is devoted to reference calculations. The SPH homogenization technique provides corrected cross sections performing an equivalence between coarse and refined calculations. The post processing module of APOLLO generate either APOLLIB to be used by APOLLO or NEPLIB for reactor diffusion calculation. The cross section library of APOLLO contains data and self-shielding data for more than 400 isotopes. APOLLO is able to compute the depletion of any medium accounting for any heavy isotope or fission product chain. 21 refs
A comparison of different quasi-newton acceleration methods for partitioned multi-physics codes
CSIR Research Space (South Africa)
Haelterman, R
2018-02-01
Full Text Available & structures, 88/7, pp. 446–457 (2010) 8. J.E. Dennis, J.J. More´, Quasi-Newton methods: motivation and theory. SIAM Rev. 19, pp. 46–89 (1977) A Comparison of Quasi-Newton Acceleration Methods 15 9. J.E. Dennis, R.B. Schnabel, Least Change Secant Updates... Dois Metodos de Broyden. Mat. Apl. Comput. 1/2, pp. 135– 143 (1982) 25. J.M. Martinez, A quasi-Newton method with modification of one column per iteration. Com- puting 33, pp. 353–362 (1984) 26. J.M. Martinez, M.C. Zambaldi, An Inverse Column...
Quasi-Newton methods for the acceleration of multi-physics codes
CSIR Research Space (South Africa)
Haelterman, R
2017-08-01
Full Text Available .E. Dennis, J.J. More´, Quasi-Newton methods: motivation and theory. SIAM Rev. 19, pp. 46–89 (1977) [11] J.E. Dennis, R.B. Schnabel, Least Change Secant Updates for quasi- Newton methods. SIAM Rev. 21, pp. 443–459 (1979) [12] G. Dhondt, CalculiX CrunchiX USER...) [25] J.M. Martinez, M.C. Zambaldi, An Inverse Column-Updating Method for solving large-scale nonlinear systems of equations. Optim. Methods Softw. 1, pp. 129–140 (1992) [26] J.M. Martinez, On the convergence of the column-updating method. Comp. Appl...
Multi-Physics Simulation of TREAT Kinetics using MAMMOTH
Energy Technology Data Exchange (ETDEWEB)
DeHart, Mark; Gleicher, Frederick; Ortensi, Javier; Alberti, Anthony; Palmer, Todd
2015-11-01
With the advent of next generation reactor systems and new fuel designs, the U.S. Department of Energy (DOE) has identified the need for the resumption of transient testing of nuclear fuels. DOE has decided that the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory (INL) is best suited for future testing. TREAT is a thermal neutron spectrum nuclear test facility that is designed to test nuclear fuels in transient scenarios. These specific fuels transient tests range from simple temperature transients to full fuel melt accidents. The current TREAT core is driven by highly enriched uranium (HEU) dispersed in a graphite matrix (1:10000 U-235/C atom ratio). At the center of the core, fuel is removed allowing for the insertion of an experimental test vehicle. TREAT’s design provides experimental flexibility and inherent safety during neutron pulsing. This safety stems from the graphite in the driver fuel having a strong negative temperature coefficient of reactivity resulting from a thermal Maxwellian shift with increased leakage, as well as graphite acting as a temperature sink. Air cooling is available, but is generally used post-transient for heat removal. DOE and INL have expressed a desire to develop a simulation capability that will accurately model the experiments before they are irradiated at the facility, with an emphasis on effective and safe operation while minimizing experimental time and cost. At INL, the Multi-physics Object Oriented Simulation Environment (MOOSE) has been selected as the model development framework for this work. This paper describes the results of preliminary simulations of a TREAT fuel element under transient conditions using the MOOSE-based MAMMOTH reactor physics tool.
Modelling transport phenomena in a multi-physics context
Marra, Francesco
2015-01-01
Innovative heating research on cooking, pasteurization/sterilization, defrosting, thawing and drying, often focuses on areas which include the assessment of processing time, evaluation of heating uniformity, studying the impact on quality attributes of the final product as well as considering the energy efficiency of these heating processes. During the last twenty years, so-called electro-heating-processes (radio-frequency - RF, microwaves - MW and ohmic - OH) gained a wide interest in industrial food processing and many applications using the above mentioned technologies have been developed with the aim of reducing processing time, improving process efficiency and, in many cases, the heating uniformity. In the area of innovative heating, electro-heating accounts for a considerable portion of both the scientific literature and commercial applications, which can be subdivided into either direct electro-heating (as in the case of OH heating) where electrical current is applied directly to the food or indirect electro-heating (e.g. MW and RF heating) where the electrical energy is firstly converted to electromagnetic radiation which subsequently generates heat within a product. New software packages, which make easier solution of PDEs based mathematical models, and new computers, capable of larger RAM and more efficient CPU performances, allowed an increasing interest about modelling transport phenomena in systems and processes - as the ones encountered in food processing - that can be complex in terms of geometry, composition, boundary conditions but also - as in the case of electro-heating assisted applications - in terms of interaction with other physical phenomena such as displacement of electric or magnetic field. This paper deals with the description of approaches used in modelling transport phenomena in a multi-physics context such as RF, MW and OH assisted heating.
Modelling transport phenomena in a multi-physics context
Energy Technology Data Exchange (ETDEWEB)
Marra, Francesco [Dipartimento di Ingegneria Chimica e Alimentare - Università degli studi di Salerno Via Ponte Don Melillo - 84084 Fisciano SA (Italy)
2015-01-22
Innovative heating research on cooking, pasteurization/sterilization, defrosting, thawing and drying, often focuses on areas which include the assessment of processing time, evaluation of heating uniformity, studying the impact on quality attributes of the final product as well as considering the energy efficiency of these heating processes. During the last twenty years, so-called electro-heating-processes (radio-frequency - RF, microwaves - MW and ohmic - OH) gained a wide interest in industrial food processing and many applications using the above mentioned technologies have been developed with the aim of reducing processing time, improving process efficiency and, in many cases, the heating uniformity. In the area of innovative heating, electro-heating accounts for a considerable portion of both the scientific literature and commercial applications, which can be subdivided into either direct electro-heating (as in the case of OH heating) where electrical current is applied directly to the food or indirect electro-heating (e.g. MW and RF heating) where the electrical energy is firstly converted to electromagnetic radiation which subsequently generates heat within a product. New software packages, which make easier solution of PDEs based mathematical models, and new computers, capable of larger RAM and more efficient CPU performances, allowed an increasing interest about modelling transport phenomena in systems and processes - as the ones encountered in food processing - that can be complex in terms of geometry, composition, boundary conditions but also - as in the case of electro-heating assisted applications - in terms of interaction with other physical phenomena such as displacement of electric or magnetic field. This paper deals with the description of approaches used in modelling transport phenomena in a multi-physics context such as RF, MW and OH assisted heating.
Multiphysical modelling of fluid transport through osteo-articular media
Directory of Open Access Journals (Sweden)
Thibault Lemaire
2010-03-01
Full Text Available In this study, a multiphysical description of fluid transport through osteo-articular porous media is presented. Adapted from the model of Moyne and Murad, which is intended to describe clayey materials behaviour, this multiscale modelling allows for the derivation of the macroscopic response of the tissue from microscopical information. First the model is described. At the pore scale, electrohydrodynamics equations governing the electrolyte movement are coupled with local electrostatics (Gauss-Poisson equation, and ionic transport equations. Using a change of variables and an asymptotic expansion method, the macroscopic description is carried out. Results of this model are used to show the importance of couplings effects on the mechanotransduction of compact bone remodelling.Neste estudo uma descrição multifísica do transporte de fluidos em meios porosos osteo articulares é apresentada. Adaptado a partir do modelo de Moyne e Murad proposto para descrever o comportamento de materiais argilosos a modelagem multiescala permite a derivação da resposta macroscópica do tecido a partir da informação microscópica. Na primeira parte o modelo é apresentado. Na escala do poro as equações da eletro-hidrodinâmica governantes do movimento dos eletrolitos são acopladas com a eletrostática local (equação de Gauss-Poisson e as equações de transporte iônico. Usando uma mudança de variáveis e o método de expansão assintótica a derivação macroscópica é conduzida. Resultados do modelo proposto são usados para salientar a importância dos efeitos de acoplamento sobre a transdução mecânica da remodelagem de ossos compactados.
Modelling transport phenomena in a multi-physics context
International Nuclear Information System (INIS)
Marra, Francesco
2015-01-01
Innovative heating research on cooking, pasteurization/sterilization, defrosting, thawing and drying, often focuses on areas which include the assessment of processing time, evaluation of heating uniformity, studying the impact on quality attributes of the final product as well as considering the energy efficiency of these heating processes. During the last twenty years, so-called electro-heating-processes (radio-frequency - RF, microwaves - MW and ohmic - OH) gained a wide interest in industrial food processing and many applications using the above mentioned technologies have been developed with the aim of reducing processing time, improving process efficiency and, in many cases, the heating uniformity. In the area of innovative heating, electro-heating accounts for a considerable portion of both the scientific literature and commercial applications, which can be subdivided into either direct electro-heating (as in the case of OH heating) where electrical current is applied directly to the food or indirect electro-heating (e.g. MW and RF heating) where the electrical energy is firstly converted to electromagnetic radiation which subsequently generates heat within a product. New software packages, which make easier solution of PDEs based mathematical models, and new computers, capable of larger RAM and more efficient CPU performances, allowed an increasing interest about modelling transport phenomena in systems and processes - as the ones encountered in food processing - that can be complex in terms of geometry, composition, boundary conditions but also - as in the case of electro-heating assisted applications - in terms of interaction with other physical phenomena such as displacement of electric or magnetic field. This paper deals with the description of approaches used in modelling transport phenomena in a multi-physics context such as RF, MW and OH assisted heating
International Nuclear Information System (INIS)
Richard, Joshua; Galloway, Jack; Fensin, Michael; Trellue, Holly
2015-01-01
Highlights: • A modular mapping methodogy for neutronic-thermal hydraulic nuclear reactor multiphysics, SMITHERS, has been developed. • Written in Python, SMITHERS takes a novel object-oriented approach for facilitating data transitions between solvers. This approach enables near-instant compatibility with existing MCNP/MONTEBURNS input decks. • It also allows for coupling with thermal-hydraulic solvers of various levels of fidelity. • Two BWR and PWR test problems are presented for verifying correct functionality of the SMITHERS code routines. - Abstract: A novel object-oriented modular mapping methodology for externally coupled neutronics–thermal hydraulics multiphysics simulations was developed. The Simulator using MCNP with Integrated Thermal-Hydraulics for Exploratory Reactor Studies (SMITHERS) code performs on-the-fly mapping of material-wise power distribution tallies implemented by MCNP-based neutron transport/depletion solvers for use in estimating coolant temperature and density distributions with a separate thermal-hydraulic solver. The key development of SMITHERS is that it reconstructs the hierarchical geometry structure of the material-wise power generation tallies from the depletion solver automatically, with only a modicum of additional information required from the user. Additionally, it performs the basis mapping from the combinatorial geometry of the depletion solver to the required geometry of the thermal-hydraulic solver in a generalizable manner, such that it can transparently accommodate varying levels of thermal-hydraulic solver geometric fidelity, from the nodal geometry of multi-channel analysis solvers to the pin-cell level of discretization for sub-channel analysis solvers. The mapping methodology was specifically developed to be flexible enough such that it could successfully integrate preexisting depletion solver case files with different thermal-hydraulic solvers. This approach allows the user to tailor the selection of a
A 1D-2D coupled SPH-SWE model applied to open channel flow simulations in complicated geometries
Chang, Kao-Hua; Sheu, Tony Wen-Hann; Chang, Tsang-Jung
2018-05-01
In this study, a one- and two-dimensional (1D-2D) coupled model is developed to solve the shallow water equations (SWEs). The solutions are obtained using a Lagrangian meshless method called smoothed particle hydrodynamics (SPH) to simulate shallow water flows in converging, diverging and curved channels. A buffer zone is introduced to exchange information between the 1D and 2D SPH-SWE models. Interpolated water discharge values and water surface levels at the internal boundaries are prescribed as the inflow/outflow boundary conditions in the two SPH-SWE models. In addition, instead of using the SPH summation operator, we directly solve the continuity equation by introducing a diffusive term to suppress oscillations in the predicted water depth. The performance of the two approaches in calculating the water depth is comprehensively compared through a case study of a straight channel. Additionally, three benchmark cases involving converging, diverging and curved channels are adopted to demonstrate the ability of the proposed 1D and 2D coupled SPH-SWE model through comparisons with measured data and predicted mesh-based numerical results. The proposed model provides satisfactory accuracy and guaranteed convergence.
Sequential creep-fatigue interaction in austenitic stainless steel type 316L-SPH
International Nuclear Information System (INIS)
Tavassoli, A.A.; Mottot, M.; Petrequin, P.
1986-01-01
Influence of a prior creep or fatigue exposure on subsequent fatigue or creep properties of stainless steel type 316 L SPH has been investigated. The results obtained are used to verify the validity of time and cycle fraction rule and to obtain information on the effect of very long intermittent hold times on low cycle fatigue properties, as well as on transitory loads occurring during normal service of some structural components of LMFBR reactors. Creep and fatigue tests have been carried out at 600 0 C and under conditions yielding equal or different fatigue saturation and creep stresses. Prior creep damage levels introduced range from primary to tertiary creep, whilst those of fatigue span from 20 to 70 percent of fatigue life. In both creep-fatigue and fatigue-creep sequences in the absence of a permanent prior damage (cavitation or cracking) the subsequent resistance of 316 L-SPH to fatigue or creep is unchanged, if not improved. Thin foils prepared from the specimens confirmed these observations and showed that the dislocation substructure developed during the first mode of testing is quickly replaced by that of the second mode. Grain boundary cavitation does not occur in 316 L-SPH during creep exposures to well beyond the apparent end of secondary stage and as a result prior creep exposures up to approximately 80% of rupture life do not affect fatigue properties. Conversely, significant surface cracks were found in the prior fatigue tested specimens after above about 50% life. In the presence of such cracks the subsequent creep damage was localized at the tip of the main crack and the remaining creep life was found to be usually proportional to the effective specimen cross section. Creep and fatigue sequential damage are not necessarily additive and this type of loadings are in general less severe than the repeated creep-fatigue cycling. 17 refs.
Acceleration methods for multi-physics compressible flow
Peles, Oren; Turkel, Eli
2018-04-01
In this work we investigate the Runge-Kutta (RK)/Implicit smoother scheme as a convergence accelerator for complex multi-physics flow problems including turbulent, reactive and also two-phase flows. The flows considered are subsonic, transonic and supersonic flows in complex geometries, and also can be either steady or unsteady flows. All of these problems are considered to be a very stiff. We then introduce an acceleration method for the compressible Navier-Stokes equations. We start with the multigrid method for pure subsonic flow, including reactive flows. We then add the Rossow-Swanson-Turkel RK/Implicit smoother that enables performing all these complex flow simulations with a reasonable CFL number. We next discuss the RK/Implicit smoother for time dependent problem and also for low Mach numbers. The preconditioner includes an intrinsic low Mach number treatment inside the smoother operator. We also develop a modified Roe scheme with a corresponding flux Jacobian matrix. We then give the extension of the method for real gas and reactive flow. Reactive flows are governed by a system of inhomogeneous Navier-Stokes equations with very stiff source terms. The extension of the RK/Implicit smoother requires an approximation of the source term Jacobian. The properties of the Jacobian are very important for the stability of the method. We discuss what the chemical physics theory of chemical kinetics tells about the mathematical properties of the Jacobian matrix. We focus on the implication of the Le-Chatelier's principle on the sign of the diagonal entries of the Jacobian. We present the implementation of the method for turbulent flow. We use a two RANS turbulent model - one equation model - Spalart-Allmaras and a two-equation model - k-ω SST model. The last extension is for two-phase flows with a gas as a main phase and Eulerian representation of a dispersed particles phase (EDP). We present some examples for such flow computations inside a ballistic evaluation
Overview of SPH-ALE applications for hydraulic turbines in ANDRITZ Hydro
Rentschler, M.; Marongiu, J. C.; Neuhauser, M.; Parkinson, E.
2018-02-01
Over the past 13 years, ANDRITZ Hydro has developed an in-house tool based on the SPH-ALE method for applications in flow simulations in hydraulic turbines. The initial motivation is related to the challenging simulation of free surface flows in Pelton turbines, where highly dynamic water jets interact with rotating buckets, creating thin water jets traveling inside the housing and possibly causing disturbances on the runner. The present paper proposes an overview of industrial applications allowed by the developed tool, including design evaluation of Pelton runners and casings, transient operation of Pelton units and free surface flows in hydraulic structures.
Spatio-Temporal Process Simulation of Dam-Break Flood Based on SPH
Wang, H.; Ye, F.; Ouyang, S.; Li, Z.
2018-04-01
On the basis of introducing the SPH (Smooth Particle Hydrodynamics) simulation method, the key research problems were given solutions in this paper, which ere the spatial scale and temporal scale adapting to the GIS(Geographical Information System) application, the boundary condition equations combined with the underlying surface, and the kernel function and parameters applicable to dam-break flood simulation. In this regards, a calculation method of spatio-temporal process emulation with elaborate particles for dam-break flood was proposed. Moreover the spatio-temporal process was dynamic simulated by using GIS modelling and visualization. The results show that the method gets more information, objectiveness and real situations.
International Nuclear Information System (INIS)
Miyamoto, Akira; Sato, Etsuko; Sato, Ryo; Inaba, Kenji; Hatakeyama, Nozomu
2014-01-01
In collaboration with experimental experts we have reported in the present conference (Hatakeyama, N. et al., “Experiment-integrated multi-scale, multi-physics computational chemistry simulation applied to corrosion behaviour of BWR structural materials”) the results of multi-scale multi-physics computational chemistry simulations applied to the corrosion behaviour of BWR structural materials. In macro-scale, a macroscopic simulator of anode polarization curve was developed to solve the spatially one-dimensional electrochemical equations on the material surface in continuum level in order to understand the corrosion behaviour of typical BWR structural material, SUS304. The experimental anode polarization behaviours of each pure metal were reproduced by fitting all the rates of electrochemical reactions and then the anode polarization curve of SUS304 was calculated by using the same parameters and found to reproduce the experimental behaviour successfully. In meso-scale, a kinetic Monte Carlo (KMC) simulator was applied to an actual-time simulation of the morphological corrosion behaviour under the influence of an applied voltage. In micro-scale, an ultra-accelerated quantum chemical molecular dynamics (UA-QCMD) code was applied to various metallic oxide surfaces of Fe 2 O 3 , Fe 3 O 4 , Cr 2 O 3 modelled as same as water molecules and dissolved metallic ions on the surfaces, then the dissolution and segregation behaviours were successfully simulated dynamically by using UA-QCMD. In this paper we describe details of the multi-scale, multi-physics computational chemistry method especially the UA-QCMD method. This method is approximately 10,000,000 times faster than conventional first-principles molecular dynamics methods based on density-functional theory (DFT), and the accuracy was also validated for various metals and metal oxides compared with DFT results. To assure multi-scale multi-physics computational chemistry simulation based on the UA-QCMD method for
Maiti, Aparna; Takabe, Kazuaki; Hait, Nitai C
2017-04-01
About 40,000 American women die from metastatic breast cancer each year despite advancements in treatment. Approximately, 15% of breast cancers are triple-negative for estrogen receptor, progesterone receptor, and HER2. Triple-negative cancer is characterized by more aggressive, harder to treat with conventional approaches and having a greater possibility of recurrence. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid signaling mediator has emerged as a key regulatory molecule in breast cancer progression. Therefore, we investigated whether cytosolic sphingosine kinase type 1 (SphK1) and nuclear sphingosine kinase type 2 (SphK2), the enzymes that make S1P are critical for growth and PI3K/AKT, ERK-MAP kinase mediated survival signaling of lung metastatic variant LM2-4 breast cancer cells, generated from the parental triple-negative MDA-MB-231 human breast cancer cell line. Similar with previous report, SphKs/S1P signaling is critical for the growth and survival of estrogen receptor positive MCF-7 human breast cancer cells, was used as our study control. MDA-MB-231 did not show a significant effect of SphKs/S1P signaling on AKT, ERK, and p38 pathways. In contrast, LM2-4 cells that gained lung metastatic phenotype from primary MDA-MB-231 cells show a significant effect of SphKs/S1P signaling requirement on cell growth, survival, and cell motility. PF-543, a selective potent inhibitor of SphK1, attenuated epidermal growth factor (EGF)-mediated cell growth and survival signaling through inhibition of AKT, ERK, and p38 MAP kinase pathways mainly in LM2-4 cells but not in parental MDA-MB-231 human breast cancer cells. Moreover, K-145, a selective inhibitor of SphK2, markedly attenuated EGF-mediated cell growth and survival of LM2-4 cells. We believe this study highlights the importance of SphKs/S1P signaling in metastatic triple-negative breast cancers and targeted therapies. Copyright © 2017 Elsevier Inc. All rights reserved.
De Padova, Diana; Mossa, Michele; Sibilla, Stefano
2018-02-01
This paper shows the results of the smooth particle hydrodynamics (SPH) modelling of the hydraulic jump at an abrupt drop, where the transition from supercritical to subcritical flow is characterised by several flow patterns depending upon the inflow and tailwater conditions. SPH simulations are obtained by a pseudo-compressible XSPH scheme with pressure smoothing; turbulent stresses are represented either by an algebraic mixing-length model, or by a two-equation k- ɛ model. The numerical model is applied to analyse the occurrence of oscillatory flow conditions between two different jump types characterised by quasi-periodic oscillation, and the results are compared with experiments performed at the hydraulics laboratory of Bari Technical University. The purpose of this paper is to obtain a deeper understanding of the physical features of a flow which is in general difficult to be reproduced numerically, owing to its unstable character: in particular, vorticity and turbulent kinetic energy fields, velocity, water depth and pressure spectra downstream of the jump, and velocity and pressure cross-correlations can be computed and analysed.
A splitting integration scheme for the SPH simulation of concentrated particle suspensions
Bian, Xin; Ellero, Marco
2014-01-01
Simulating nearly contacting solid particles in suspension is a challenging task due to the diverging behavior of short-range lubrication forces, which pose a serious time-step limitation for explicit integration schemes. This general difficulty limits severely the total duration of simulations of concentrated suspensions. Inspired by the ideas developed in [S. Litvinov, M. Ellero, X.Y. Hu, N.A. Adams, J. Comput. Phys. 229 (2010) 5457-5464] for the simulation of highly dissipative fluids, we propose in this work a splitting integration scheme for the direct simulation of solid particles suspended in a Newtonian liquid. The scheme separates the contributions of different forces acting on the solid particles. In particular, intermediate- and long-range multi-body hydrodynamic forces, which are computed from the discretization of the Navier-Stokes equations using the smoothed particle hydrodynamics (SPH) method, are taken into account using an explicit integration; for short-range lubrication forces, velocities of pairwise interacting solid particles are updated implicitly by sweeping over all the neighboring pairs iteratively, until convergence in the solution is obtained. By using the splitting integration, simulations can be run stably and efficiently up to very large solid particle concentrations. Moreover, the proposed scheme is not limited to the SPH method presented here, but can be easily applied to other simulation techniques employed for particulate suspensions.
Multiphysics pore-scale model for the rehydration of porous foods
Sman, van der R.G.M.; Vergeldt, F.J.; As, van H.; Dalen, van G.; Voda, A.; Duynhoven, van J.P.M.
2014-01-01
In this paper we present a pore-scale model describing the multiphysics occurring during the rehydration of freeze-dried vegetables. This pore-scale model is part of a multiscale simulation model, which should explain the effect of microstructure and pre-treatments on the rehydration rate.
Non-Linear Multi-Physics Analysis and Multi-Objective Optimization in Electroheating Applications
Czech Academy of Sciences Publication Activity Database
di Barba, P.; Doležel, Ivo; Mognaschi, M. E.; Savini, A.; Karban, P.
2014-01-01
Roč. 50, č. 2 (2014), s. 7016604-7016604 ISSN 0018-9464 Institutional support: RVO:61388998 Keywords : coupled multi-physics problems * finite element method * non-linear equations Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.386, year: 2014
Validation of a 3D multi-physics model for unidirectional silicon solidification
Simons, P.; Lankhorst, A.M.; Habraken, A.; Faber, A.J.; Tiuleanu, D.; Pingel, R.
2012-01-01
A model for transient movements of solidification fronts has been added to X-stream, an existing multi-physics simulation program for high temperature processes with flow and chemical reactions. The implementation uses an enthalpy formulation and works on fixed grids. First we show the results of a
Assessing climate impact on reinforced concrete durability with a multi-physics model
DEFF Research Database (Denmark)
Michel, Alexander; Flint, Madeleine M.
to shorter-term fluctuations in boundary conditions and therefore may underestimate climate change impacts. A highly sensitive fully-coupled, validated, multi-physics model for heat, moisture and ion transport and corrosion was used to assess a reinforced concrete structure located in coastal Norfolk...
DEFF Research Database (Denmark)
Khan, Mohammad Rezwan; Kær, Søren Knudsen
2016-01-01
A three-dimensional multiphysics-based thermal model of a battery pack is presented. The model is intended to demonstrate the cooling mechanism inside the battery pack. Heat transfer (HT) and computational fluid dynamics (CFD) physics are coupled for both time-dependent and steady-state simulatio...
ACME - Algorithms for Contact in a Multiphysics Environment API Version 1.0
International Nuclear Information System (INIS)
BROWN, KEVIN H.; SUMMERS, RANDALL M.; GLASS, MICHEAL W.; GULLERUD, ARNE S.; HEINSTEIN, MARTIN W.; JONES, REESE E.
2001-01-01
An effort is underway at Sandia National Laboratories to develop a library of algorithms to search for potential interactions between surfaces represented by analytic and discretized topological entities. This effort is also developing algorithms to determine forces due to these interactions for transient dynamics applications. This document describes the Application Programming Interface (API) for the ACME (Algorithms for Contact in a Multiphysics Environment) library
Investigating Darcy-scale assumptions by means of a multiphysics algorithm
Tomin, Pavel; Lunati, Ivan
2016-09-01
Multiphysics (or hybrid) algorithms, which couple Darcy and pore-scale descriptions of flow through porous media in a single numerical framework, are usually employed to decrease the computational cost of full pore-scale simulations or to increase the accuracy of pure Darcy-scale simulations when a simple macroscopic description breaks down. Despite the massive increase in available computational power, the application of these techniques remains limited to core-size problems and upscaling remains crucial for practical large-scale applications. In this context, the Hybrid Multiscale Finite Volume (HMsFV) method, which constructs the macroscopic (Darcy-scale) problem directly by numerical averaging of pore-scale flow, offers not only a flexible framework to efficiently deal with multiphysics problems, but also a tool to investigate the assumptions used to derive macroscopic models and to better understand the relationship between pore-scale quantities and the corresponding macroscale variables. Indeed, by direct comparison of the multiphysics solution with a reference pore-scale simulation, we can assess the validity of the closure assumptions inherent to the multiphysics algorithm and infer the consequences for macroscopic models at the Darcy scale. We show that the definition of the scale ratio based on the geometric properties of the porous medium is well justified only for single-phase flow, whereas in case of unstable multiphase flow the nonlinear interplay between different forces creates complex fluid patterns characterized by new spatial scales, which emerge dynamically and weaken the scale-separation assumption. In general, the multiphysics solution proves very robust even when the characteristic size of the fluid-distribution patterns is comparable with the observation length, provided that all relevant physical processes affecting the fluid distribution are considered. This suggests that macroscopic constitutive relationships (e.g., the relative
Full Core Multiphysics Simulation with Offline Mesh Deformation
Energy Technology Data Exchange (ETDEWEB)
Merzari, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Yu, Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Thomas, J. W. [Argonne National Lab. (ANL), Argonne, IL (United States); Obabko, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Jain, Rajeev [Argonne National Lab. (ANL), Argonne, IL (United States); Mahadevan, Vijay [Argonne National Lab. (ANL), Argonne, IL (United States); Solberg, Jerome [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ferencz, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Whitesides, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2015-12-21
In this report, building on previous reports issued in FY13 we describe our continued efforts to integrate thermal/hydraulics, neutronics, and structural mechanics modeling codes to perform coupled analysis of a representative fast sodium-cooled reactor core. The focus of the present report is a full core simulation with off-line mesh deformation.
A multi-physics analysis for the actuation of the SSS in opal reactor
Directory of Open Access Journals (Sweden)
Ferraro Diego
2018-01-01
Full Text Available OPAL is a 20 MWth multi-purpose open-pool type Research Reactor located at Lucas Heights, Australia. It was designed, built and commissioned by INVAP between 2000 and 2006 and it has been operated by the Australia Nuclear Science and Technology Organization (ANSTO showing a very good overall performance. On November 2016, OPAL reached 10 years of continuous operation, becoming one of the most reliable and available in its kind worldwide, with an unbeaten record of being fully operational 307 days a year. One of the enhanced safety features present in this state-of-art reactor is the availability of an independent, diverse and redundant Second Shutdown System (SSS, which consists in the drainage of the heavy water reflector contained in the Reflector Vessel. As far as high quality experimental data is available from reactor commissioning and operation stages and even from early component design validation stages, several models both regarding neutronic and thermo-hydraulic approaches have been developed during recent years using advanced calculations tools and the novel capabilities to couple them. These advanced models were developed in order to assess the capability of such codes to simulate and predict complex behaviours and develop highly detail analysis. In this framework, INVAP developed a three-dimensional CFD model that represents the detailed hydraulic behaviour of the Second Shutdown System for an actuation scenario, where the heavy water drainage 3D temporal profiles inside the Reflector Vessel can be obtained. This model was validated, comparing the computational results with experimental measurements performed in a real-size physical model built by INVAP during early OPAL design engineering stages. Furthermore, detailed 3D Serpent Monte Carlo models are also available, which have been already validated with experimental data from reactor commissioning and operating cycles. In the present work the neutronic and thermohydraulic
A multi-physics analysis for the actuation of the SSS in opal reactor
Ferraro, Diego; Alberto, Patricio; Villarino, Eduardo; Doval, Alicia
2018-05-01
OPAL is a 20 MWth multi-purpose open-pool type Research Reactor located at Lucas Heights, Australia. It was designed, built and commissioned by INVAP between 2000 and 2006 and it has been operated by the Australia Nuclear Science and Technology Organization (ANSTO) showing a very good overall performance. On November 2016, OPAL reached 10 years of continuous operation, becoming one of the most reliable and available in its kind worldwide, with an unbeaten record of being fully operational 307 days a year. One of the enhanced safety features present in this state-of-art reactor is the availability of an independent, diverse and redundant Second Shutdown System (SSS), which consists in the drainage of the heavy water reflector contained in the Reflector Vessel. As far as high quality experimental data is available from reactor commissioning and operation stages and even from early component design validation stages, several models both regarding neutronic and thermo-hydraulic approaches have been developed during recent years using advanced calculations tools and the novel capabilities to couple them. These advanced models were developed in order to assess the capability of such codes to simulate and predict complex behaviours and develop highly detail analysis. In this framework, INVAP developed a three-dimensional CFD model that represents the detailed hydraulic behaviour of the Second Shutdown System for an actuation scenario, where the heavy water drainage 3D temporal profiles inside the Reflector Vessel can be obtained. This model was validated, comparing the computational results with experimental measurements performed in a real-size physical model built by INVAP during early OPAL design engineering stages. Furthermore, detailed 3D Serpent Monte Carlo models are also available, which have been already validated with experimental data from reactor commissioning and operating cycles. In the present work the neutronic and thermohydraulic models, available for
Energy Technology Data Exchange (ETDEWEB)
Le Pallec, J. C.; Crouzet, N.; Bergeaud, V.; Delavaud, C. [CEA/DEN/DM2S, CEA/Saclay, 91191 Gif sur Yvette Cedex (France)
2012-07-01
The control of uncertainties in the field of reactor physics and their propagation in best-estimate modeling are a major issue in safety analysis. In this framework, the CEA develops a methodology to perform multi-physics simulations including uncertainties analysis. The present paper aims to present and apply this methodology for the analysis of an accidental situation such as REA (Rod Ejection Accident). This accident is characterized by a strong interaction between the different areas of the reactor physics (neutronic, fuel thermal and thermal hydraulic). The modeling is performed with CRONOS2 code. The uncertainties analysis has been conducted with the URANIE platform developed by the CEA: For each identified response from the modeling (output) and considering a set of key parameters with their uncertainties (input), a surrogate model in the form of a neural network has been produced. The set of neural networks is then used to carry out a sensitivity analysis which consists on a global variance analysis with the determination of the Sobol indices for all responses. The sensitivity indices are obtained for the input parameters by an approach based on the use of polynomial chaos. The present exercise helped to develop a methodological flow scheme, to consolidate the use of URANIE tool in the framework of parallel calculations. Finally, the use of polynomial chaos allowed computing high order sensitivity indices and thus highlighting and classifying the influence of identified uncertainties on each response of the analysis (single and interaction effects). (authors)
Li, Yingkun; Chen, Xiong; Xu, Jinsheng; Zhou, Changsheng; Musa, Omer
2018-05-01
In this paper, numerical investigation of ignition transient in a dual pulse solid rocket motor has been conducted. An in-house code has been developed in order to solve multi-physics governing equations, including unsteady compressible flow, heat conduction and structural dynamic. The simplified numerical models for solid propellant ignition and combustion have been added. The conventional serial staggered algorithm is adopted to simulate the fluid structure interaction problems in a loosely-coupled manner. The accuracy of the coupling procedure is validated by the behavior of a cantilever panel subjected to a shock wave. Then, the detailed flow field development, flame propagation characteristics, pressure evolution in the combustion chamber, and the structural response of metal diaphragm are analyzed carefully. The burst-time and burst-pressure of the metal diaphragm are also obtained. The individual effects of the igniter's mass flow rate, metal diaphragm thickness and diameter on the ignition transient have been systemically compared. The numerical results show that the evolution of the flow field in the combustion chamber, the temperature distribution on the propellant surface and the pressure loading on the metal diaphragm surface present a strong three-dimensional behavior during the initial ignition stage. The rupture of metal diaphragm is not only related to the magnitude of pressure loading on the diaphragm surface, but also to the history of pressure loading. The metal diaphragm thickness and diameter have a significant effect on the burst-time and burst-pressure of metal diaphragm.
Periodic Boundary Conditions in the ALEGRA Finite Element Code
International Nuclear Information System (INIS)
Aidun, John B.; Robinson, Allen C.; Weatherby, Joe R.
1999-01-01
This document describes the implementation of periodic boundary conditions in the ALEGRA finite element code. ALEGRA is an arbitrary Lagrangian-Eulerian multi-physics code with both explicit and implicit numerical algorithms. The periodic boundary implementation requires a consistent set of boundary input sets which are used to describe virtual periodic regions. The implementation is noninvasive to the majority of the ALEGRA coding and is based on the distributed memory parallel framework in ALEGRA. The technique involves extending the ghost element concept for interprocessor boundary communications in ALEGRA to additionally support on- and off-processor periodic boundary communications. The user interface, algorithmic details and sample computations are given
SPH Simulation of Liquid Scattering from the Edge of a Rotary Atomizer
Izawa, Seiichiro; Ito, Takuya; Shigeta, Masaya; Fukunishi, Yu
2013-11-01
Three-dimensional incompressible SPH method is used to simulate the behavior of liquid scattering from the edge of a rotary atomizer. Rotary atomizers have been widely used for spraying, painting and coating, for instance, in the automobile industry. However, how the spray droplets are formed after leaving the edge of the rotary atomizer is not well understood, because the scale of the phenomenon is very small and the speed of rotation is very fast. The present computational result shows that while the liquid forms a film on the surface of the rotating disk of the atomizer, it quickly deforms into many thin columns after leaving the disk edge, and these columns soon break up into fine droplets which spread out in the radial direction. The size of droplets tends to become smaller with the increase in the disk rotating speed. The results show good agreement with the experimental observations.
3D SPH numerical simulation of the wave generated by the Vajont rockslide
Vacondio, R.; Mignosa, P.; Pagani, S.
2013-09-01
A 3D numerical modeling of the wave generated by the Vajont slide, one of the most destructive ever occurred, is presented in this paper. A meshless Lagrangian Smoothed Particle Hydrodynamics (SPH) technique was adopted to simulate the highly fragmented violent flow generated by the falling slide in the artificial reservoir. The speed-up achievable via General Purpose Graphic Processing Units (GP-GPU) allowed to adopt the adequate resolution to describe the phenomenon. The comparison with the data available in literature showed that the results of the numerical simulation reproduce satisfactorily the maximum run-up, also the water surface elevation in the residual lake after the event. Moreover, the 3D velocity field of the flow during the event and the discharge hydrograph which overtopped the dam, were obtained.
Numerical Simulation of Shear Slitting Process of Grain Oriented Silicon Steel using SPH Method
Directory of Open Access Journals (Sweden)
Bohdal Łukasz
2017-12-01
Full Text Available Mechanical cutting allows separating of sheet material at low cost and therefore remains the most popular way to produce laminations for electrical machines and transformers. However, recent investigations revealed the deteriorating effect of cutting on the magnetic properties of the material close to the cut edge. The deformations generate elastic stresses in zones adjacent to the area of plastically deformed and strongly affect the magnetic properties. The knowledge about residual stresses is necessary in designing the process. This paper presents the new apprach of modeling residual stresses induced in shear slitting of grain oriented electrical steel using mesh-free method. The applications of SPH (Smoothed Particle Hydrodynamics methodology to the simulation and analysis of 3D shear slitting process is presented. In experimental studies, an advanced vision-based technology based on digital image correlation (DIC for monitoring the cutting process is used.
Crystal Structure of Faradaurate-279: Au279(SPh-tBu)84 Plasmonic Nanocrystal Molecules.
Sakthivel, Naga Arjun; Theivendran, Shevanuja; Ganeshraj, Vigneshraja; Oliver, Allen G; Dass, Amala
2017-11-01
We report the discovery of an unprecedentedly large, 2.2 nm diameter, thiolate protected gold nanocrystal characterized by single crystal X-ray crystallography (sc-XRD), Au 279 (SPh-tBu) 84 named Faradaurate-279 (F-279) in honor of Michael Faraday's (1857) pioneering work on nanoparticles. F-279 nanocrystal has a core-shell structure containing a truncated octahedral core with bulk face-centered cubic-like arrangement, yet a nanomolecule with a precise number of metal atoms and thiolate ligands. The Au 279 S 84 geometry was established from a low-temperature 120 K sc-XRD study at 0.90 Å resolution. The atom counts in core-shell structure of Au 279 follows the mathematical formula for magic number shells: Au@Au 12 @Au 42 @Au 92 @Au 54 , which is further protected by a final shell of Au 48 . Au 249 core is protected by three types of staple motifs, namely: 30 bridging, 18 monomeric, and 6 dimeric staple motifs. Despite the presence of such diverse staple motifs, Au 279 S 84 structure has a chiral pseudo-D 3 symmetry. The core-shell structure can be viewed as nested, concentric polyhedra, containing a total of five forms of Archimedean solids. A comparison between the Au 279 and Au 309 cuboctahedral superatom model in shell-wise growth is illustrated. F-279 can be synthesized and isolated in high purity in milligram quantities using size exclusion chromatography, as evidenced by mass spectrometry. Electrospray ionization-mass spectrometry independently verifies the X-ray diffraction study based heavy atoms formula, Au 279 S 84 , and establishes the molecular formula with the complete ligands, namely, Au 279 (SPh-tBu) 84 . It is also the smallest gold nanocrystal to exhibit metallic behavior, with a surface plasmon resonance band around 510 nm.
Local Group dSph radio survey with ATCA (I): observations and background sources
Regis, Marco; Richter, Laura; Colafrancesco, Sergio; Massardi, Marcella; de Blok, W. J. G.; Profumo, Stefano; Orford, Nicola
2015-04-01
Dwarf spheroidal (dSph) galaxies are key objects in near-field cosmology, especially in connection to the study of galaxy formation and evolution at small scales. In addition, dSphs are optimal targets to investigate the nature of dark matter. However, while we begin to have deep optical photometric observations of the stellar population in these objects, little is known so far about their diffuse emission at any observing frequency, and hence on thermal and non-thermal plasma possibly residing within dSphs. In this paper, we present deep radio observations of six local dSphs performed with the Australia Telescope Compact Array (ATCA) at 16 cm wavelength. We mosaicked a region of radius of about 1 deg around three `classical' dSphs, Carina, Fornax, and Sculptor, and of about half of degree around three `ultrafaint' dSphs, BootesII, Segue2, and Hercules. The rms noise level is below 0.05 mJy for all the maps. The restoring beams full width at half-maximum ranged from 4.2 arcsec × 2.5 arcsec to 30.0 arcsec × 2.1 arcsec in the most elongated case. A catalogue including the 1392 sources detected in the six dSph fields is reported. The main properties of the background sources are discussed, with positions and fluxes of brightest objects compared with the FIRST, NVSS, and SUMSS observations of the same fields. The observed population of radio emitters in these fields is dominated by synchrotron sources. We compute the associated source number counts at 2 GHz down to fluxes of 0.25 mJy, which prove to be in agreement with AGN count models.
Energy Technology Data Exchange (ETDEWEB)
Bonaccorsi, Th
2007-09-15
A Material Testing Reactor (MTR) makes it possible to irradiate material samples under intense neutron and photonic fluxes. These experiments are carried out in experimental devices localised in the reactor core or in periphery (reflector). Available physics simulation tools only treat, most of the time, one physics field in a very precise way. Multi-physic simulations of irradiation experiments therefore require a sequential use of several calculation codes and data exchanges between these codes: this corresponds to problems coupling. In order to facilitate multi-physic simulations, this thesis sets up a data model based on data-processing objects, called Technological Entities. This data model is common to all of the physics fields. It permits defining the geometry of an irradiation device in a parametric way and to associate information about materials to it. Numerical simulations are encapsulated into interfaces providing the ability to call specific functionalities with the same command (to initialize data, to launch calculations, to post-treat, to get results,... ). Thus, once encapsulated, numerical simulations can be re-used for various studies. This data model is developed in a SALOME platform component. The first application case made it possible to perform neutronic simulations (OSIRIS reactor and RJH) coupled with fuel behavior simulations. In a next step, thermal hydraulics could also be taken into account. In addition to the improvement of the calculation accuracy due to the physical phenomena coupling, the time spent in the development phase of the simulation is largely reduced and the possibilities of uncertainty treatment are under consideration. (author)
Multi-physics modeling of plasma-material interactions
Lasa, Ane; Green, David; Canik, John; Younkin, Timothy; Blondel, Sophie; Wirth, Brian; Drobny, Jon; Curreli, Davide
2017-10-01
Plasma-material interactions (PMI) can degrade both plasma and material properties. Often, PMI modeling focuses on either the plasma or surface. Here, we present an integrated model with high-fidelity codes coupled within the IPS framework that self-consistently addresses PMI. The model includes, calculation of spatially resolved influx of plasma and impurities to the surface and their implantation; surface erosion and roughening; evolution of implanted species and sub-surface composition; and transport of eroded particles across the plasma and their re-deposition. The model is applied and successfully compared to dedicated PISCES linear device experiments, where a tungsten (W) target was exposed to helium (He) plasma. The present contribution will focus on the analysis of W erosion, He retention and sub-surface gas bubble and surface composition evolution, under the different He plasma conditions across the surface that are calculated by impurity transport modeling. Impact of code coupling, reflected as interplay between surface erosion, fuel / impurity implantation and retention, and evolution of target composition, as well as sensitivity of these processes to plasma exposure conditions is also analyzed in detail. This work is supported by the US DOE under contract DE-AC05-00OR22725.
The cell method for electrical engineering and multiphysics problems an introduction
Alotto, Piergiorgio; Repetto, Maurizio; Rosso, Carlo
2013-01-01
This book presents a numerical scheme for the solution of field problems governed by partial differential equations: the cell method. The technique lends itself naturally to the solution of multiphysics problems with several interacting phenomena. The Cell Method, based on a space-time tessellation, is intimately related to the work of Tonti and to his ideas of classification diagrams or, as they are nowadays called, Tonti diagrams: a graphical representation of the problem's equations made possible by a suitable selection of a space-time framework relating physical variables to each other. The main features of the cell method are presented and links with many other discrete numerical methods (finite integration techniques, finite difference time domain, finite volumes, mimetic finite differences, etc.) are discussed. After outlining the theoretical basis of the method, a set of physical problems which have been solved with the cell method is described. These single and multiphysics problems stem from the aut...
Multiphysics simulation by design for electrical machines, power electronics and drives
Rosu, Marius; Lin, Dingsheng; Ionel, Dan M; Popescu, Mircea; Blaabjerg, Frede; Rallabandi, Vandana; Staton, David
2018-01-01
This book combines the knowledge of experts from both academia and the software industry to present theories of multiphysics simulation by design for electrical machines, power electronics, and drives. The comprehensive design approach described within supports new applications required by technologies sustaining high drive efficiency. The highlighted framework considers the electric machine at the heart of the entire electric drive. The book also emphasizes the simulation by design concept--a concept that frames the entire highlighted design methodology, which is described and illustrated by various advanced simulation technologies. Multiphysics Simulation by Design for Electrical Machines, Power Electronics and Drives begins with the basics of electrical machine design and manufacturing tolerances. It also discusses fundamental aspects of the state of the art design process and includes examples from industrial practice. It explains FEM-based analysis techniques for electrical machine design--providing deta...
A Multi-physics Approach to Understanding Low Porosity Soils and Reservoir Rocks
Prasad, M.; Mapeli, C.; Livo, K.; Hasanov, A.; Schindler, M.; Ou, L.
2017-12-01
We present recent results on our multiphysics approach to rock physics. Thus, we evaluate geophysical measurements by simultaneously measuring petrophysical properties or imaging strains. In this paper, we present simultaneously measured acoustic and electrical anisotropy data as functions of pressure. Similarly, we present strains and strain localization images simultaneously acquired with acoustic measurements as well as NMR T2 relaxations on pressurized fluids as well as rocks saturated with these pressurized fluids. Such multiphysics experiments allow us to constrain and assign appropriate causative mechanisms to development rock physics models. They also allow us to decouple various effects, for example, fluid versus pressure, on geophysical measurements. We show applications towards reservoir characterization as well as CO2 sequestration applications.
A posteriori error analysis of multiscale operator decomposition methods for multiphysics models
International Nuclear Information System (INIS)
Estep, D; Carey, V; Tavener, S; Ginting, V; Wildey, T
2008-01-01
Multiphysics, multiscale models present significant challenges in computing accurate solutions and for estimating the error in information computed from numerical solutions. In this paper, we describe recent advances in extending the techniques of a posteriori error analysis to multiscale operator decomposition solution methods. While the particulars of the analysis vary considerably with the problem, several key ideas underlie a general approach being developed to treat operator decomposition multiscale methods. We explain these ideas in the context of three specific examples
NREL Multiphysics Modeling Tools and ISC Device for Designing Safer Li-Ion Batteries
Energy Technology Data Exchange (ETDEWEB)
Pesaran, Ahmad A.; Yang, Chuanbo
2016-03-24
The National Renewable Energy Laboratory has developed a portfolio of multiphysics modeling tools to aid battery designers better understand the response of lithium ion batteries to abusive conditions. We will discuss this portfolio, which includes coupled electrical, thermal, chemical, electrochemical, and mechanical modeling. These models can simulate the response of a cell to overheating, overcharge, mechanical deformation, nail penetration, and internal short circuit. Cell-to-cell thermal propagation modeling will be discussed.
Multi-physics modeling in electrical engineering. Application to a magneto-thermo-mechanical model
International Nuclear Information System (INIS)
Journeaux, Antoine
2013-01-01
The modeling of multi-physics problems in electrical engineering is presented, with an application to the numerical computation of vibrations within the end windings of large turbo-generators. This study is divided into four parts: the impositions of current density, the computation of local forces, the transfer of data between disconnected meshes, and the computation of multi-physics problems using weak coupling, Firstly, the representation of current density within numerical models is presented. The process is decomposed into two stages: the construction of the initial current density, and the determination of a divergence-free field. The representation of complex geometries makes the use of analytical methods impossible. A method based on an electrokinetic problem is used and a fully geometrical method are tested. The geometrical method produces results closer to the real current density than the electrokinetic problem. Methods to compute forces are numerous, and this study focuses on the virtual work principle and the Laplace force considering the recommendations of the literature. Laplace force is highly accurate but is applicable only if the permeability is uniform. The virtual work principle is finally preferred as it appears as the most general way to compute local forces. Mesh-to-mesh data transfer methods are developed to compute multi-physics models using multiples meshes adapted to the subproblems and multiple computational software. The interpolation method, a locally conservative projection, and an orthogonal projection are compared. Interpolation method is said to be fast but highly diffusive, and the orthogonal projections are highly accurate. The locally conservative method produces results similar to the orthogonal projection but avoid the assembly of linear systems. The numerical computation of multi-physical problems using multiple meshes and projections is then presented. However for a given class of problems, there is not an unique coupling
Energy Technology Data Exchange (ETDEWEB)
Fajeau, M; Nguyen, L T; Saunier, J [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)
1966-09-01
This code handles the following problems: -1) Analysis of thermal experiments on a water loop at high or low pressure; steady state or transient behavior; -2) Analysis of thermal and hydrodynamic behavior of water-cooled and moderated reactors, at either high or low pressure, with boiling permitted; fuel elements are assumed to be flat plates: - Flowrate in parallel channels coupled or not by conduction across plates, with conditions of pressure drops or flowrate, variable or not with respect to time is given; the power can be coupled to reactor kinetics calculation or supplied by the code user. The code, containing a schematic representation of safety rod behavior, is a one dimensional, multi-channel code, and has as its complement (FLID), a one-channel, two-dimensional code. (authors) [French] Ce code permet de traiter les problemes ci-dessous: 1. Depouillement d'essais thermiques sur boucle a eau, haute ou basse pression, en regime permanent ou transitoire; 2. Etudes thermiques et hydrauliques de reacteurs a eau, a plaques, a haute ou basse pression, ebullition permise: - repartition entre canaux paralleles, couples on non par conduction a travers plaques, pour des conditions de debit ou de pertes de charge imposees, variables ou non dans le temps; - la puissance peut etre couplee a la neutronique et une representation schematique des actions de securite est prevue. Ce code (Cactus) a une dimension d'espace et plusieurs canaux, a pour complement Flid qui traite l'etude d'un seul canal a deux dimensions. (auteurs)
Directory of Open Access Journals (Sweden)
Rohit Saluja
2017-05-01
Full Text Available Sphingolipid metabolites are emerging as important signaling molecules in allergic diseases specifically asthma. One of the sphingolipid metabolite, sphingosine-1-phosphate (S1P, is involved in cell differentiation, proliferation, survival, migration, and angiogenesis. In the allergic diseases, alteration of S1P levels influences the differentiation and responsiveness of mast cells (MCs. S1P is synthesized by two sphingosine kinases (SphKs, sphingosine kinase 1, and sphingosine kinase 2. Engagement of IgE to the FcεRI receptor induces the activation of both the SphKs and generates S1P. Furthermore, SphKs are also essential to FcεRI-mediated MC activation. Activated MCs export S1P into the extracellular space and causes inflammatory response and tissue remodeling. S1P signaling has dual role in allergic responses. Activation of SphKs and secretion of S1P are required for MC activation; however, S1P signaling plays a vital role in the recovery from anaphylaxis. Several non-coding RNAs have been shown to play a crucial role in controlling the MC-associated inflammatory and allergic responses. Thus, S1P signaling pathway and its regulation by non-coding RNA could be explored as an exciting potential therapeutic target for asthma and other MC-associated diseases.
Optimization of an implicit constrained multi-physics system for motor wheels of electric vehicle
International Nuclear Information System (INIS)
Lei, Fei; Du, Bin; Liu, Xin; Xie, Xiaoping; Chai, Tian
2016-01-01
In this paper, implicit constrained multi-physics model of a motor wheel for an electric vehicle is built and then optimized. A novel optimization approach is proposed to solve the compliance problem between implicit constraints and stochastic global optimization. Firstly, multi-physics model of motor wheel is built from the theories of structural mechanics, electromagnetism and thermal physics. Then, implicit constraints are applied from the vehicle performances and magnetic characteristics. Implicit constrained optimization is carried out by a series of unconstrained optimization and verifications. In practice, sequentially updated subspaces are designed to completely substitute the original design space in local areas. In each subspace, a solution is obtained and is then verified by the implicit constraints. Optimal solutions which satisfy the implicit constraints are accepted as final candidates. The final global optimal solution is optimized from those candidates. Discussions are carried out to discover the differences between optimal solutions with unconstrained problem and different implicit constrained problems. Results show that the implicit constraints have significant influences on the optimal solution and the proposed approach is effective in finding the optimals. - Highlights: • An implicit constrained multi-physics model is built for sizing a motor wheel. • Vehicle dynamic performances are applied as implicit constraints for nonlinear system. • An efficient novel optimization is proposed to explore the constrained design space. • The motor wheel is optimized to achieve maximum efficiency on vehicle dynamics. • Influences of implicit constraints on vehicle performances are compared and analyzed.
Foundational development of an advanced nuclear reactor integrated safety code
International Nuclear Information System (INIS)
Clarno, Kevin; Lorber, Alfred Abraham; Pryor, Richard J.; Spotz, William F.; Schmidt, Rodney Cannon; Belcourt, Kenneth; Hooper, Russell Warren; Humphries, Larry LaRon
2010-01-01
This report describes the activities and results of a Sandia LDRD project whose objective was to develop and demonstrate foundational aspects of a next-generation nuclear reactor safety code that leverages advanced computational technology. The project scope was directed towards the systems-level modeling and simulation of an advanced, sodium cooled fast reactor, but the approach developed has a more general applicability. The major accomplishments of the LDRD are centered around the following two activities. (1) The development and testing of LIME, a Lightweight Integrating Multi-physics Environment for coupling codes that is designed to enable both 'legacy' and 'new' physics codes to be combined and strongly coupled using advanced nonlinear solution methods. (2) The development and initial demonstration of BRISC, a prototype next-generation nuclear reactor integrated safety code. BRISC leverages LIME to tightly couple the physics models in several different codes (written in a variety of languages) into one integrated package for simulating accident scenarios in a liquid sodium cooled 'burner' nuclear reactor. Other activities and accomplishments of the LDRD include (a) further development, application and demonstration of the 'non-linear elimination' strategy to enable physics codes that do not provide residuals to be incorporated into LIME, (b) significant extensions of the RIO CFD code capabilities, (c) complex 3D solid modeling and meshing of major fast reactor components and regions, and (d) an approach for multi-physics coupling across non-conformal mesh interfaces.
Foundational development of an advanced nuclear reactor integrated safety code.
Energy Technology Data Exchange (ETDEWEB)
Clarno, Kevin (Oak Ridge National Laboratory, Oak Ridge, TN); Lorber, Alfred Abraham; Pryor, Richard J.; Spotz, William F.; Schmidt, Rodney Cannon; Belcourt, Kenneth (Ktech Corporation, Albuquerque, NM); Hooper, Russell Warren; Humphries, Larry LaRon
2010-02-01
This report describes the activities and results of a Sandia LDRD project whose objective was to develop and demonstrate foundational aspects of a next-generation nuclear reactor safety code that leverages advanced computational technology. The project scope was directed towards the systems-level modeling and simulation of an advanced, sodium cooled fast reactor, but the approach developed has a more general applicability. The major accomplishments of the LDRD are centered around the following two activities. (1) The development and testing of LIME, a Lightweight Integrating Multi-physics Environment for coupling codes that is designed to enable both 'legacy' and 'new' physics codes to be combined and strongly coupled using advanced nonlinear solution methods. (2) The development and initial demonstration of BRISC, a prototype next-generation nuclear reactor integrated safety code. BRISC leverages LIME to tightly couple the physics models in several different codes (written in a variety of languages) into one integrated package for simulating accident scenarios in a liquid sodium cooled 'burner' nuclear reactor. Other activities and accomplishments of the LDRD include (a) further development, application and demonstration of the 'non-linear elimination' strategy to enable physics codes that do not provide residuals to be incorporated into LIME, (b) significant extensions of the RIO CFD code capabilities, (c) complex 3D solid modeling and meshing of major fast reactor components and regions, and (d) an approach for multi-physics coupling across non-conformal mesh interfaces.
Theivendran, Shevanuja; Dass, Amala
2017-08-01
Ultrasmall nanomolecules (<2 nm) such as Au 25 (SCH 2 CH 2 Ph) 18 , Au 38 (SCH 2 CH 2 Ph) 24 , and Au 144 (SCH 2 CH 2 Ph) 60 are well studied and can be prepared using established synthetic procedures. No such synthetic protocols that result in high yield products from commercially available starting materials exist for Au 36 (SPh-X) 24 . Here, we report a synthetic procedure for the large-scale synthesis of highly stable Au 36 (SPh-X) 24 with a yield of ∼42%. Au 36 (SPh-X) 24 was conveniently synthesized by using tert-butylbenzenethiol (HSPh-tBu, TBBT) as the ligand, giving a more stable product with better shelf life and higher yield than previously reported for making Au 36 (SPh) 24 from thiophenol (PhSH). The choice of thiol, solvent, and reaction conditions were modified for the optimization of the synthetic procedure. The purposes of this work are to (1) optimize the existing procedure to obtain stable product with better yield, (2) develop a scalable synthetic procedure, (3) demonstrate the superior stability of Au 36 (SPh-tBu) 24 when compared to Au 36 (SPh) 24 , and (4) demonstrate the reproducibility and robustness of the optimized synthetic procedure.
SPH modeling of fluid-solid interaction for dynamic failure analysis of fluid-filled thin shells
Caleyron, F.; Combescure, A.; Faucher, V.; Potapov, S.
2013-05-01
This work concerns the prediction of failure of a fluid-filled tank under impact loading, including the resulting fluid leakage. A water-filled steel cylinder associated with a piston is impacted by a mass falling at a prescribed velocity. The cylinder is closed at its base by an aluminum plate whose characteristics are allowed to vary. The impact on the piston creates a pressure wave in the fluid which is responsible for the deformation of the plate and, possibly, the propagation of cracks. The structural part of the problem is modeled using Mindlin-Reissner finite elements (FE) and Smoothed Particle Hydrodynamics (SPH) shells. The modeling of the fluid is also based on an SPH formulation. The problem involves significant fluid-structure interactions (FSI) which are handled through a master-slave-based method and the pinballs method. Numerical results are compared to experimental data.
Simulating non-Newtonian flows with the moving particle semi-implicit method with an SPH kernel
International Nuclear Information System (INIS)
Xiang, Hao; Chen, Bin
2015-01-01
The moving particle semi-implicit (MPS) method and smoothed particle hydrodynamics (SPH) are commonly used mesh-free particle methods for free surface flows. The MPS method has superiority in incompressible flow simulation and simple programing. However, the crude kernel function is not accurate enough for the discretization of the divergence of the shear stress tensor by the particle inconsistency when the MPS method is extended to non-Newtonian flows. This paper presents an improved MPS method with an SPH kernel to simulate non-Newtonian flows. To improve the consistency of the partial derivative, the SPH cubic spline kernel and the Taylor series expansion are combined with the MPS method. This approach is suitable for all non-Newtonian fluids that can be described with τ = μ(|γ|) Δ (where τ is the shear stress tensor, μ is the viscosity, |γ| is the shear rate, and Δ is the strain tensor), e.g., the Casson and Cross fluids. Two examples are simulated including the Newtonian Poiseuille flow and container filling process of the Cross fluid. The results of Poiseuille flow are more accurate than the traditional MPS method, and different filling processes are obtained with good agreement with previous results, which verified the validation of the new algorithm. For the Cross fluid, the jet fracture length can be correlated with We 0.28 Fr 0.78 (We is the Weber number, Fr is the Froude number). (paper)
Massmann, J.; Nagel, T.; Bilke, L.; Böttcher, N.; Heusermann, S.; Fischer, T.; Kumar, V.; Schäfers, A.; Shao, H.; Vogel, P.; Wang, W.; Watanabe, N.; Ziefle, G.; Kolditz, O.
2016-12-01
As part of the German site selection process for a high-level nuclear waste repository, different repository concepts in the geological candidate formations rock salt, clay stone and crystalline rock are being discussed. An open assessment of these concepts using numerical simulations requires physical models capturing the individual particularities of each rock type and associated geotechnical barrier concept to a comparable level of sophistication. In a joint work group of the Helmholtz Centre for Environmental Research (UFZ) and the German Federal Institute for Geosciences and Natural Resources (BGR), scientists of the UFZ are developing and implementing multiphysical process models while BGR scientists apply them to large scale analyses. The advances in simulation methods for waste repositories are incorporated into the open-source code OpenGeoSys. Here, recent application-driven progress in this context is highlighted. A robust implementation of visco-plasticity with temperature-dependent properties into a framework for the thermo-mechanical analysis of rock salt will be shown. The model enables the simulation of heat transport along with its consequences on the elastic response as well as on primary and secondary creep or the occurrence of dilatancy in the repository near field. Transverse isotropy, non-isothermal hydraulic processes and their coupling to mechanical stresses are taken into account for the analysis of repositories in clay stone. These processes are also considered in the near field analyses of engineered barrier systems, including the swelling/shrinkage of the bentonite material. The temperature-dependent saturation evolution around the heat-emitting waste container is described by different multiphase flow formulations. For all mentioned applications, we illustrate the workflow from model development and implementation, over verification and validation, to repository-scale application simulations using methods of high performance computing.
Multi-Scale Multi-physics Methods Development for the Calculation of Hot-Spots in the NGNP
International Nuclear Information System (INIS)
Downar, Thomas; Seker, Volkan
2013-01-01
Radioactive gaseous fission products are released out of the fuel element at a significantly higher rate when the fuel temperature exceeds 1600°C in high-temperature gas-cooled reactors (HTGRs). Therefore, it is of paramount importance to accurately predict the peak fuel temperature during all operational and design-basis accident conditions. The current methods used to predict the peak fuel temperature in HTGRs, such as the Next-Generation Nuclear Plant (NGNP), estimate the average fuel temperature in a computational mesh modeling hundreds of fuel pebbles or a fuel assembly in a pebble-bed reactor (PBR) or prismatic block type reactor (PMR), respectively. Experiments conducted in operating HTGRs indicate considerable uncertainty in the current methods and correlations used to predict actual temperatures. The objective of this project is to improve the accuracy in the prediction of local 'hot' spots by developing multi-scale, multi-physics methods and implementing them within the framework of established codes used for NGNP analysis.The multi-scale approach which this project will implement begins with defining suitable scales for a physical and mathematical model and then deriving and applying the appropriate boundary conditions between scales. The macro scale is the greatest length that describes the entire reactor, whereas the meso scale models only a fuel block in a prismatic reactor and ten to hundreds of pebbles in a pebble bed reactor. The smallest scale is the micro scale--the level of a fuel kernel of the pebble in a PBR and fuel compact in a PMR--which needs to be resolved in order to calculate the peak temperature in a fuel kernel.
Multi-Scale Multi-physics Methods Development for the Calculation of Hot-Spots in the NGNP
Energy Technology Data Exchange (ETDEWEB)
Downar, Thomas [Univ. of Michigan, Ann Arbor, MI (United States); Seker, Volkan [Univ. of Michigan, Ann Arbor, MI (United States)
2013-04-30
Radioactive gaseous fission products are released out of the fuel element at a significantly higher rate when the fuel temperature exceeds 1600°C in high-temperature gas-cooled reactors (HTGRs). Therefore, it is of paramount importance to accurately predict the peak fuel temperature during all operational and design-basis accident conditions. The current methods used to predict the peak fuel temperature in HTGRs, such as the Next-Generation Nuclear Plant (NGNP), estimate the average fuel temperature in a computational mesh modeling hundreds of fuel pebbles or a fuel assembly in a pebble-bed reactor (PBR) or prismatic block type reactor (PMR), respectively. Experiments conducted in operating HTGRs indicate considerable uncertainty in the current methods and correlations used to predict actual temperatures. The objective of this project is to improve the accuracy in the prediction of local "hot" spots by developing multi-scale, multi-physics methods and implementing them within the framework of established codes used for NGNP analysis.The multi-scale approach which this project will implement begins with defining suitable scales for a physical and mathematical model and then deriving and applying the appropriate boundary conditions between scales. The macro scale is the greatest length that describes the entire reactor, whereas the meso scale models only a fuel block in a prismatic reactor and ten to hundreds of pebbles in a pebble bed reactor. The smallest scale is the micro scale--the level of a fuel kernel of the pebble in a PBR and fuel compact in a PMR--which needs to be resolved in order to calculate the peak temperature in a fuel kernel.
Analysis of New Aerodynamic Design of the Nose Cone Section Using CFD and SPH
Directory of Open Access Journals (Sweden)
Bogdan-Alexandru BELEGA
2015-06-01
Full Text Available A new nose cones concept that promises a gain in performance over existing conventional nose cones is discussed in this paper. It is shown that significant performance gains result from the adaptation of the exhaust flow to the ambient pressure. For this complex work, it was necessary to collect and study the various nose cone shapes and the equations describing them? The paper objective was to identify the types of nose cones with ejector channels and specific aerodynamic characteristics of different types of nose cones. The scope of this paper is to develop some prototype profiles with outstanding aerodynamic qualities and low cost for use in construction projects for missile increasing their range and effect on target. The motivation for such a work is caused by a lack of data on aerodynamics for profiles of some nose cones and especially improved aerodynamic qualities that can be used in designing missiles/ rockets. This design method consists of a geometry creation step in which a three-dimensional geometry is generated, a mathematical model presented and a simple flow analysis (FLUENT Simulation from SolidWorks2012 and ANSYS Simulation with SPH for fluid-structure interaction, step which predicts the air intake mass flow rate. Flow phenomena observed in numerical simulations during different nose cone operations are highlighted, critical design aspects and operation conditions are discussed, and performance characteristics of the selected nose cone are presented.
Granata, R; Trovato, L; Lupia, E; Sala, G; Settanni, F; Camussi, G; Ghidoni, R; Ghigo, E
2007-04-01
Angiogenesis is critical for development and repair, and is a prominent feature of many pathological conditions. Based on evidence that insulin-like growth factor binding protein (IGFBP)-3 enhances cell motility and activates sphingosine kinase (SphK) in human endothelial cells, we have investigated whether IGFBP-3 plays a role in promoting angiogenesis. IGFBP-3 potently induced network formation by human endothelial cells on Matrigel. Moreover, it up-regulated proangiogenic genes, such as vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP)-2 and -9. IGFBP-3 even induced membrane-type 1 MMP (MT1-MMP), which regulates MMP-2 activation. Decreasing SphK1 expression by small interfering RNA (siRNA), blocked IGFBP-3-induced network formation and inhibited VEGF, MT1-MMP but not IGF-I up-regulation. IGF-I activated SphK, leading to sphingosine-1-phosphate (S1P) formation. The IGF-I effect on SphK activity was blocked by specific inhibitors of IGF-IR, PI3K/Akt and ERK1/2 phosphorylation. The disruption of IGF-I signaling prevented the IGFBP-3 effect on tube formation, SphK activity and VEGF release. Blocking ERK1/2 signaling caused the loss of SphK activation and VEGF and IGF-I up-regulation. Finally, IGFBP-3 dose-dependently stimulated neovessel formation into subcutaneous implants of Matrigel in vivo. Thus, IGFBP-3 positively regulates angiogenesis through involvement of IGF-IR signaling and subsequent SphK/S1P activation.
Modelling organs, tissues, cells and devices using Matlab and Comsol multiphysics
Dokos, Socrates
2017-01-01
This book presents a theoretical and practical overview of computational modeling in bioengineering, focusing on a range of applications including electrical stimulation of neural and cardiac tissue, implantable drug delivery, cancer therapy, biomechanics, cardiovascular dynamics, as well as fluid-structure interaction for modelling of organs, tissues, cells and devices. It covers the basic principles of modeling and simulation with ordinary and partial differential equations using MATLAB and COMSOL Multiphysics numerical software. The target audience primarily comprises postgraduate students and researchers, but the book may also be beneficial for practitioners in the medical device industry.
Study of stability of dc glow discharges with the use of Comsol Multiphysics software
Energy Technology Data Exchange (ETDEWEB)
Almeida, P G C; Benilov, M S; Faria, M J [Departamento de Fisica, Universidade da Madeira, Largo do Municipio, 9000 Funchal (Portugal)
2011-10-19
Stability of different axially symmetric modes of current transfer in dc glow discharges is investigated in the framework of the linear stability theory with the use of Comsol Multiphysics software. Conditions of current-controlled microdischarges in xenon are treated as an example. Both real and complex eigenvalues have been detected, meaning that perturbations can vary with time both monotonically and with oscillations. In general, results given by the linear stability theory confirm intuitive concepts developed in the literature and conform to the experiment. On the other hand, suggestions are provided for further experimental and theoretical work.
High-fidelity plasma codes for burn physics
Energy Technology Data Exchange (ETDEWEB)
Cooley, James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Graziani, Frank [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Marinak, Marty [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Murillo, Michael [Michigan State Univ., East Lansing, MI (United States)
2016-10-19
Accurate predictions of equation of state (EOS), ionic and electronic transport properties are of critical importance for high-energy-density plasma science. Transport coefficients inform radiation-hydrodynamic codes and impact diagnostic interpretation, which in turn impacts our understanding of the development of instabilities, the overall energy balance of burning plasmas, and the efficacy of self-heating from charged-particle stopping. Important processes include thermal and electrical conduction, electron-ion coupling, inter-diffusion, ion viscosity, and charged particle stopping. However, uncertainties in these coefficients are not well established. Fundamental plasma science codes, also called high-fidelity plasma codes, are a relatively recent computational tool that augments both experimental data and theoretical foundations of transport coefficients. This paper addresses the current status of HFPC codes and their future development, and the potential impact they play in improving the predictive capability of the multi-physics hydrodynamic codes used in HED design.
Parallelization of Subchannel Analysis Code MATRA
International Nuclear Information System (INIS)
Kim, Seongjin; Hwang, Daehyun; Kwon, Hyouk
2014-01-01
A stand-alone calculation of MATRA code used up pertinent computing time for the thermal margin calculations while a relatively considerable time is needed to solve the whole core pin-by-pin problems. In addition, it is strongly required to improve the computation speed of the MATRA code to satisfy the overall performance of the multi-physics coupling calculations. Therefore, a parallel approach to improve and optimize the computability of the MATRA code is proposed and verified in this study. The parallel algorithm is embodied in the MATRA code using the MPI communication method and the modification of the previous code structure was minimized. An improvement is confirmed by comparing the results between the single and multiple processor algorithms. The speedup and efficiency are also evaluated when increasing the number of processors. The parallel algorithm was implemented to the subchannel code MATRA using the MPI. The performance of the parallel algorithm was verified by comparing the results with those from the MATRA with the single processor. It is also noticed that the performance of the MATRA code was greatly improved by implementing the parallel algorithm for the 1/8 core and whole core problems
(U) Ristra Next Generation Code Report
Energy Technology Data Exchange (ETDEWEB)
Hungerford, Aimee L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Daniel, David John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-09-22
LANL’s Weapons Physics management (ADX) and ASC program office have defined a strategy for exascale-class application codes that follows two supportive, and mutually risk-mitigating paths: evolution for established codes (with a strong pedigree within the user community) based upon existing programming paradigms (MPI+X); and Ristra (formerly known as NGC), a high-risk/high-reward push for a next-generation multi-physics, multi-scale simulation toolkit based on emerging advanced programming systems (with an initial focus on data-flow task-based models exemplified by Legion [5]). Development along these paths is supported by the ATDM, IC, and CSSE elements of the ASC program, with the resulting codes forming a common ecosystem, and with algorithm and code exchange between them anticipated. Furthermore, solution of some of the more challenging problems of the future will require a federation of codes working together, using established-pedigree codes in partnership with new capabilities as they come on line. The role of Ristra as the high-risk/high-reward path for LANL’s codes is fully consistent with its role in the Advanced Technology Development and Mitigation (ATDM) sub-program of ASC (see Appendix C), in particular its emphasis on evolving ASC capabilities through novel programming models and data management technologies.
International Nuclear Information System (INIS)
Cacuci, Dan Gabriel; Badea, Madalina Corina
2014-01-01
Highlights: • We applied the PMCMPS methodology to a paradigm neutron diffusion model. • We underscore the main steps in applying PMCMPS to treat very large coupled systems. • PMCMPS reduces the uncertainties in the optimally predicted responses and model parameters. • PMCMPS is for sequentially treating coupled systems that cannot be treated simultaneously. - Abstract: This work presents paradigm applications to reactor physics of the innovative mathematical methodology for “predictive modeling of coupled multi-physics systems (PMCMPS)” developed by Cacuci (2014). This methodology enables the assimilation of experimental and computational information and computes optimally predicted responses and model parameters with reduced predicted uncertainties, taking fully into account the coupling terms between the multi-physics systems, but using only the computational resources that would be needed to perform predictive modeling on each system separately. The paradigm examples presented in this work are based on a simple neutron diffusion model, chosen so as to enable closed-form solutions with clear physical interpretations. These paradigm examples also illustrate the computational efficiency of the PMCMPS, which enables the assimilation of additional experimental information, with a minimal increase in computational resources, to reduce the uncertainties in predicted responses and best-estimate values for uncertain model parameters, thus illustrating how very large systems can be treated without loss of information in a sequential rather than simultaneous manner
3D multiphysics modeling of superconducting cavities with a massively parallel simulation suite
Directory of Open Access Journals (Sweden)
Oleksiy Kononenko
2017-10-01
Full Text Available Radiofrequency cavities based on superconducting technology are widely used in particle accelerators for various applications. The cavities usually have high quality factors and hence narrow bandwidths, so the field stability is sensitive to detuning from the Lorentz force and external loads, including vibrations and helium pressure variations. If not properly controlled, the detuning can result in a serious performance degradation of a superconducting accelerator, so an understanding of the underlying detuning mechanisms can be very helpful. Recent advances in the simulation suite ace3p have enabled realistic multiphysics characterization of such complex accelerator systems on supercomputers. In this paper, we present the new capabilities in ace3p for large-scale 3D multiphysics modeling of superconducting cavities, in particular, a parallel eigensolver for determining mechanical resonances, a parallel harmonic response solver to calculate the response of a cavity to external vibrations, and a numerical procedure to decompose mechanical loads, such as from the Lorentz force or piezoactuators, into the corresponding mechanical modes. These capabilities have been used to do an extensive rf-mechanical analysis of dressed TESLA-type superconducting cavities. The simulation results and their implications for the operational stability of the Linac Coherent Light Source-II are discussed.
Massimino, G.; Colombo, A.; D'Alessandro, L.; Procopio, F.; Ardito, R.; Ferrera, M.; Corigliano, A.
2018-05-01
In this paper a complete multiphysics modelling via the finite element method (FEM) of an air-coupled array of piezoelectric micromachined ultrasonic transducers (PMUT) and its experimental validation are presented. Two numerical models are described for the single transducer, axisymmetric and 3D, with the following features: the presence of fabrication induced residual stresses, which determine a non-linear initial deformed configuration of the diaphragm and a substantial fundamental mode frequency shift; the multiple coupling between different physics, namely electro-mechanical coupling for the piezo-electric model, thermo-acoustic-structural interaction and thermo-acoustic-pressure interaction for the waves propagation in the surrounding fluid. The model for the single transducer is enhanced considering the full set of PMUTs belonging to the silicon dye in a 4 × 4 array configuration. The results of the numerical multiphysics models are compared with experimental ones in terms of the initial static pre-deflection, of the diaphragm central point spectrum and of the sound intensity at 3.5 cm on the vertical direction along the axis of the diaphragm.
Advanced Multiphysics Thermal-Hydraulics Models for the High Flux Isotope Reactor
Energy Technology Data Exchange (ETDEWEB)
Jain, Prashant K [ORNL; Freels, James D [ORNL
2015-01-01
Engineering design studies to determine the feasibility of converting the High Flux Isotope Reactor (HFIR) from using highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel are ongoing at Oak Ridge National Laboratory (ORNL). This work is part of an effort sponsored by the US Department of Energy (DOE) Reactor Conversion Program. HFIR is a very high flux pressurized light-water-cooled and moderated flux-trap type research reactor. HFIR s current missions are to support neutron scattering experiments, isotope production, and materials irradiation, including neutron activation analysis. Advanced three-dimensional multiphysics models of HFIR fuel were developed in COMSOL software for safety basis (worst case) operating conditions. Several types of physics including multilayer heat conduction, conjugate heat transfer, turbulent flows (RANS model) and structural mechanics were combined and solved for HFIR s inner and outer fuel elements. Alternate design features of the new LEU fuel were evaluated using these multiphysics models. This work led to a new, preliminary reference LEU design that combines a permanent absorber in the lower unfueled region of all of the fuel plates, a burnable absorber in the inner element side plates, and a relocated and reshaped (but still radially contoured) fuel zone. Preliminary results of estimated thermal safety margins are presented. Fuel design studies and model enhancement continue.
Conductance Thin Film Model of Flexible Organic Thin Film Device using COMSOL Multiphysics
Carradero-Santiago, Carolyn; Vedrine-Pauléus, Josee
We developed a virtual model to analyze the electrical conductivity of multilayered thin films placed above a graphene conducting and flexible polyethylene terephthalate (PET) substrate. The organic layers of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as a hole conducting layer, poly(3-hexylthiophene-2,5-diyl) (P3HT), as a p-type, phenyl-C61-butyric acid methyl ester (PCBM) and as n-type, with aluminum as a top conductor. COMSOL Multiphysics was the software we used to develop the virtual model to analyze potential variations and conductivity through the thin-film layers. COMSOL Multiphysics software allows simulation and modeling of physical phenomena represented by differential equations such as heat transfer, fluid flow, electromagnetism, and structural mechanics. In this work, using the AC/DC, electric currents module we defined the geometry of the model and properties for each of the six layers: PET/graphene/PEDOT:PSS/P3HT/PCBM/aluminum. We analyzed the model with varying thicknesses of graphene and active layers (P3HT/PCBM). This simulation allowed us to analyze the electrical conductivity, and visualize the model with varying voltage potential, or bias across the plates, useful for applications in solar cell devices.
Fu, X.; Hu, L.; Lee, K. M.; Zou, J.; Ruan, X. D.; Yang, H. Y.
2010-10-01
This paper presents a method for dry calibration of an electromagnetic flowmeter (EMF). This method, which determines the voltage induced in the EMF as conductive liquid flows through a magnetic field, numerically solves a coupled set of multiphysical equations with measured boundary conditions for the magnetic, electric, and flow fields in the measuring pipe of the flowmeter. Specifically, this paper details the formulation of dry calibration and an efficient algorithm (that adaptively minimizes the number of measurements and requires only the normal component of the magnetic flux density as boundary conditions on the pipe surface to reconstruct the magnetic field involved) for computing the sensitivity of EMF. Along with an in-depth discussion on factors that could significantly affect the final precision of a dry calibrated EMF, the effects of flow disturbance on measuring errors have been experimentally studied by installing a baffle at the inflow port of the EMF. Results of the dry calibration on an actual EMF were compared against flow-rig calibration; excellent agreements (within 0.3%) between dry calibration and flow-rig tests verify the multiphysical computation of the fields and the robustness of the method. As requiring no actual flow, the dry calibration is particularly useful for calibrating large-diameter EMFs where conventional flow-rig methods are often costly and difficult to implement.
Multi-physics Model for the Aging Prediction of a Vanadium Redox Flow Battery System
International Nuclear Information System (INIS)
Merei, Ghada; Adler, Sophie; Magnor, Dirk; Sauer, Dirk Uwe
2015-01-01
Highlights: • Present a multi-physics model of vanadium redox-flow battery. • This model is essential for aging prediction. • It is applicable for VRB system of different power and capacity ratings. • Good results comparing with current research in this field. - Abstract: The all-vanadium redox-flow battery is an attractive candidate to compensate the fluctuations of non-dispatchable renewable energy generation. While several models for vanadium redox batteries have been described yet, no model has been published, which is adequate for the aging prediction. Therefore, the present paper presents a multi-physics model which determines all parameters that are essential for an aging prediction. In a following paper, the corresponding aging model of vanadium redox flow battery (VRB) is described. The model combines existing models for the mechanical losses and temperature development with new approaches for the batteries side reactions. The model was implemented in Matlab/Simulink. The modeling results presented in the paper prove to be consistent with the experimental results of other research groups
Multiphysical model of heterogenous flow moving along а channel of variable cross-section
Directory of Open Access Journals (Sweden)
М. А. Васильева
2017-10-01
Full Text Available The article deals with the problem aimed at solving the fundamental problems of developing effective methods and tools for designing, controlling and managing the stream of fluid flowing in variable-section pipelines intended for the production of pumping equipment, medical devices and used in such areas of industry as mining, chemical, food production, etc. Execution of simulation modelling of flow motion according to the scheme of twisted paddle static mixer allows to estimate the efficiency of mixing by calculating the trajectory and velocities of the suspended particles going through the mixer, and also to estimate the pressure drop on the hydraulic flow resistance. The model examines the mixing of solids dissolved in a liquid at room temperature. To visualize the process of distributing the mixture particles over the cross-section and analyzing the mixing efficiency, the Poincaréplot module of the COMSOL Multiphysics software environment was used. For the first time, a multi-physical stream of heterogeneous flow model has been developed that describes in detail the physical state of the fluid at all points of the considered section at the initial time, takes into account the design parameters of the channel (orientation, dimensions, material, etc., specifies the laws of variation of the parameters at the boundaries of the calculated section in conditions of the wave change in the internal section of the working chamber-channel of the inductive peristaltic pumping unit under the influence of the energy of the magnetic field.
Energy Technology Data Exchange (ETDEWEB)
Fiorina, Carlo, E-mail: carlo.fiorina@psi.ch [Paul Scherrer Institut, Nuclear Energy and Safety Department, Laboratory for Reactor Physics and Systems Behaviour – PSI, Villigen 5232 (Switzerland); Clifford, Ivor [Paul Scherrer Institut, Nuclear Energy and Safety Department, Laboratory for Reactor Physics and Systems Behaviour – PSI, Villigen 5232 (Switzerland); Aufiero, Manuele [LPSC-IN2P3-CNRS/UJF/Grenoble INP, 53 avenue des Martyrs, 38026 Grenoble Cedex (France); Mikityuk, Konstantin [Paul Scherrer Institut, Nuclear Energy and Safety Department, Laboratory for Reactor Physics and Systems Behaviour – PSI, Villigen 5232 (Switzerland)
2015-12-01
Highlights: • Development of a new multi-physics solver based on OpenFOAM{sup ®}. • Tight coupling of thermal-hydraulics, thermal-mechanics and neutronics. • Combined use of traditional RANS and porous-medium models. • Mesh for neutronics deformed according to the predicted displacement field. • Use of three unstructured meshes, adaptive time step, parallel computing. - Abstract: The FAST group at the Paul Scherrer Institut has been developing a code system for reactor analysis for many years. For transient analysis, this code system is currently based on a state-of-the-art coupled TRACE-PARCS routine. This work presents an attempt to supplement the FAST code system with a novel solver characterized by tight coupling between the different equations, parallel computing capabilities, adaptive time-stepping and more accurate treatment of some of the phenomena involved in a reactor transient. The new solver is based on OpenFOAM{sup ®}, an open-source C++ library for the solution of partial differential equations using finite-volume discretization. It couples together a multi-scale fine/coarse mesh sub-solver for thermal-hydraulics, a multi-group diffusion sub-solver for neutronics, a displacement-based sub-solver for thermal-mechanics and a finite-difference model for the temperature field in the fuel. It is targeted toward the analysis of pin-based reactors (e.g., liquid metal fast reactors or light water reactors) or homogeneous reactors (e.g., fast-spectrum molten salt reactors). This paper presents each “single-physics” sub-solver and the overall coupling strategy, using the sodium-cooled fast reactor as a test case, and essential code verification tests are described.
International Nuclear Information System (INIS)
Fiorina, Carlo; Clifford, Ivor; Aufiero, Manuele; Mikityuk, Konstantin
2015-01-01
Highlights: • Development of a new multi-physics solver based on OpenFOAM"®. • Tight coupling of thermal-hydraulics, thermal-mechanics and neutronics. • Combined use of traditional RANS and porous-medium models. • Mesh for neutronics deformed according to the predicted displacement field. • Use of three unstructured meshes, adaptive time step, parallel computing. - Abstract: The FAST group at the Paul Scherrer Institut has been developing a code system for reactor analysis for many years. For transient analysis, this code system is currently based on a state-of-the-art coupled TRACE-PARCS routine. This work presents an attempt to supplement the FAST code system with a novel solver characterized by tight coupling between the different equations, parallel computing capabilities, adaptive time-stepping and more accurate treatment of some of the phenomena involved in a reactor transient. The new solver is based on OpenFOAM"®, an open-source C++ library for the solution of partial differential equations using finite-volume discretization. It couples together a multi-scale fine/coarse mesh sub-solver for thermal-hydraulics, a multi-group diffusion sub-solver for neutronics, a displacement-based sub-solver for thermal-mechanics and a finite-difference model for the temperature field in the fuel. It is targeted toward the analysis of pin-based reactors (e.g., liquid metal fast reactors or light water reactors) or homogeneous reactors (e.g., fast-spectrum molten salt reactors). This paper presents each “single-physics” sub-solver and the overall coupling strategy, using the sodium-cooled fast reactor as a test case, and essential code verification tests are described.
International Nuclear Information System (INIS)
Xu Binbin; Tang Wenhui; Ran Xianwen; Xu Zhihong; Chen Hua
2012-01-01
When high energy X-ray irradiates material, it will cause energy deposition in materials, and generates thermal shock wave. At present, finite difference method is used to the numerical simulation of thermal shock usually, but if considering the inter-space between the multilayer materials, the difference method will be more difficult. This paper used the SPH method to simulate multilayer discontinuous structure irradiated by high energy X-ray, and the results show that the gap between the materials of each layer has a certain influence on the thermal shock wave intensity, but doesn't have any affect to gasification impulse. (authors)
SphK1 inhibitor II (SKI-II) inhibits acute myelogenous leukemia cell growth in vitro and in vivo
International Nuclear Information System (INIS)
Yang, Li; Weng, Wei; Sun, Zhi-Xin; Fu, Xian-Jie; Ma, Jun; Zhuang, Wen-Fang
2015-01-01
Previous studies have identified sphingosine kinase 1 (SphK1) as a potential drug target for treatment of acute myeloid leukemia (AML). In the current study, we investigated the potential anti-leukemic activity of a novel and specific SphK1 inhibitor, SKI-II. We demonstrated that SKI-II inhibited growth and survival of human AML cell lines (HL-60 and U937 cells). SKI-II was more efficient than two known SphK1 inhibitors SK1-I and FTY720 in inhibiting AML cells. Meanwhile, it induced dramatic apoptosis in above AML cells, and the cytotoxicity by SKI-II was almost reversed by the general caspase inhibitor z-VAD-fmk. SKI-II treatment inhibited SphK1 activation, and concomitantly increased level of sphingosine-1-phosphate (S1P) precursor ceramide in AML cells. Conversely, exogenously-added S1P protected against SKI-II-induced cytotoxicity, while cell permeable short-chain ceramide (C6) aggravated SKI-II's lethality against AML cells. Notably, SKI-II induced potent apoptotic death in primary human AML cells, but was generally safe to the human peripheral blood mononuclear cells (PBMCs) isolated from healthy donors. In vivo, SKI-II administration suppressed growth of U937 leukemic xenograft tumors in severe combined immunodeficient (SCID) mice. These results suggest that SKI-II might be further investigated as a promising anti-AML agent. - Highlights: • SKI-II inhibits proliferation and survival of primary and transformed AML cells. • SKI-II induces apoptotic death of AML cells, but is safe to normal PBMCs. • SKI-II is more efficient than two known SphK1 inhibitors in inhibiting AML cells. • SKI-II inhibits SphK1 activity, while increasing ceramide production in AML cells. • SKI-II dose-dependently inhibits U937 xenograft growth in SCID mice
SphK1 inhibitor II (SKI-II) inhibits acute myelogenous leukemia cell growth in vitro and in vivo
Energy Technology Data Exchange (ETDEWEB)
Yang, Li; Weng, Wei; Sun, Zhi-Xin; Fu, Xian-Jie; Ma, Jun, E-mail: majuntongrensh1@126.com; Zhuang, Wen-Fang, E-mail: wenfangzhuangmd@163.com
2015-05-15
Previous studies have identified sphingosine kinase 1 (SphK1) as a potential drug target for treatment of acute myeloid leukemia (AML). In the current study, we investigated the potential anti-leukemic activity of a novel and specific SphK1 inhibitor, SKI-II. We demonstrated that SKI-II inhibited growth and survival of human AML cell lines (HL-60 and U937 cells). SKI-II was more efficient than two known SphK1 inhibitors SK1-I and FTY720 in inhibiting AML cells. Meanwhile, it induced dramatic apoptosis in above AML cells, and the cytotoxicity by SKI-II was almost reversed by the general caspase inhibitor z-VAD-fmk. SKI-II treatment inhibited SphK1 activation, and concomitantly increased level of sphingosine-1-phosphate (S1P) precursor ceramide in AML cells. Conversely, exogenously-added S1P protected against SKI-II-induced cytotoxicity, while cell permeable short-chain ceramide (C6) aggravated SKI-II's lethality against AML cells. Notably, SKI-II induced potent apoptotic death in primary human AML cells, but was generally safe to the human peripheral blood mononuclear cells (PBMCs) isolated from healthy donors. In vivo, SKI-II administration suppressed growth of U937 leukemic xenograft tumors in severe combined immunodeficient (SCID) mice. These results suggest that SKI-II might be further investigated as a promising anti-AML agent. - Highlights: • SKI-II inhibits proliferation and survival of primary and transformed AML cells. • SKI-II induces apoptotic death of AML cells, but is safe to normal PBMCs. • SKI-II is more efficient than two known SphK1 inhibitors in inhibiting AML cells. • SKI-II inhibits SphK1 activity, while increasing ceramide production in AML cells. • SKI-II dose-dependently inhibits U937 xenograft growth in SCID mice.
Czech Academy of Sciences Publication Activity Database
Ferfecki, P.; Zapoměl, Jaroslav; Kozánek, Jan
2017-01-01
Roč. 104, February (2017), s. 1-11 ISSN 0965-9978 R&D Projects: GA ČR GA15-06621S Institutional support: RVO:61388998 Keywords : magnetorheological squeeze film dampers * magnetorheological oils * closed form formulas * multiphysical problem Subject RIV: JR - Other Machinery OBOR OECD: Mechanical engineering Impact factor: 3.000, year: 2016
Perkó, Z.
2015-01-01
This thesis presents novel adjoint and spectral methods for the sensitivity and uncertainty (S&U) analysis of multi-physics problems encountered in the field of reactor physics. The first part focuses on the steady state of reactors and extends the adjoint sensitivity analysis methods well
Resolved granular debris-flow simulations with a coupled SPH-DCDEM model
Birjukovs Canelas, Ricardo; Domínguez, José M.; Crespo, Alejandro J. C.; Gómez-Gesteira, Moncho; Ferreira, Rui M. L.
2016-04-01
Debris flows represent some of the most relevant phenomena in geomorphological events. Due to the potential destructiveness of such flows, they are the target of a vast amount of research (Takahashi, 2007 and references therein). A complete description of the internal processes of a debris-flow is however still an elusive achievement, explained by the difficulty of accurately measuring important quantities in these flows and developing a comprehensive, generalized theoretical framework capable of describing them. This work addresses the need for a numerical model applicable to granular-fluid mixtures featuring high spatial and temporal resolution, thus capable of resolving the motion of individual particles, including all interparticle contacts. This corresponds to a brute-force approach: by applying simple interaction laws at local scales the macro-scale properties of the flow should be recovered by upscaling. This methodology effectively bypasses the complexity of modelling the intermediate scales by resolving them directly. The only caveat is the need of high performance computing, a demanding but engaging research challenge. The DualSPHysics meshless numerical implementation, based on Smoothed Particle Hydrodynamics (SPH), is expanded with a Distributed Contact Discrete Element Method (DCDEM) in order to explicitly solve the fluid and the solid phase. The model numerically solves the Navier-Stokes and continuity equations for the liquid phase and Newton's motion equations for solid bodies. The interactions between solids are modelled with classical DEM approaches (Kruggel-Emden et al, 2007). Among other validation tests, an experimental set-up for stony debris flows in a slit check dam is reproduced numerically, where solid material is introduced trough a hopper assuring a constant solid discharge for the considered time interval. With each sediment particle undergoing tens of possible contacts, several thousand time-evolving contacts are efficiently treated
Directory of Open Access Journals (Sweden)
Fabio Burderi
2007-05-01
Full Text Available Motivated by the study of decipherability conditions for codes weaker than Unique Decipherability (UD, we introduce the notion of coding partition. Such a notion generalizes that of UD code and, for codes that are not UD, allows to recover the ``unique decipherability" at the level of the classes of the partition. By tacking into account the natural order between the partitions, we define the characteristic partition of a code X as the finest coding partition of X. This leads to introduce the canonical decomposition of a code in at most one unambiguouscomponent and other (if any totally ambiguouscomponents. In the case the code is finite, we give an algorithm for computing its canonical partition. This, in particular, allows to decide whether a given partition of a finite code X is a coding partition. This last problem is then approached in the case the code is a rational set. We prove its decidability under the hypothesis that the partition contains a finite number of classes and each class is a rational set. Moreover we conjecture that the canonical partition satisfies such a hypothesis. Finally we consider also some relationships between coding partitions and varieties of codes.
Software Abstractions and Methodologies for HPC Simulation Codes on Future Architectures
Directory of Open Access Journals (Sweden)
Anshu Dubey
2014-07-01
Full Text Available Simulations with multi-physics modeling have become crucial to many science and engineering fields, and multi-physics capable scientific software is as important to these fields as instruments and facilities are to experimental sciences. The current generation of mature multi-physics codes would have sustainably served their target communities with modest amount of ongoing investment for enhancing capabilities. However, the revolution occurring in the hardware architecture has made it necessary to tackle the parallelism and performance management in these codes at multiple levels. The requirements of various levels are often at cross-purposes with one another, and therefore hugely complicate the software design. All of these considerations make it essential to approach this challenge cooperatively as a community. We conducted a series of workshops under an NSF-SI2 conceptualization grant to get input from various stakeholders, and to identify broad approaches that might lead to a solution. In this position paper we detail the major concerns articulated by the application code developers, and emerging trends in utilization of programming abstractions that we found through these workshops.
Multi-Physics Demonstration Problem with the SHARP Reactor Simulation Toolkit
Energy Technology Data Exchange (ETDEWEB)
Merzari, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Yu, Y. Q. [Argonne National Lab. (ANL), Argonne, IL (United States); Thomas, J. W. [Argonne National Lab. (ANL), Argonne, IL (United States); Obabko, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Jain, Rajeev [Argonne National Lab. (ANL), Argonne, IL (United States); Mahadevan, Vijay [Argonne National Lab. (ANL), Argonne, IL (United States); Tautges, Timothy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Solberg, Jerome [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ferencz, Robert Mark [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Whitesides, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2015-12-21
This report describes to employ SHARP to perform a first-of-a-kind analysis of the core radial expansion phenomenon in an SFR. This effort required significant advances in the framework Multi-Physics Demonstration Problem with the SHARP Reactor Simulation Toolkit used to drive the coupled simulations, manipulate the mesh in response to the deformation of the geometry, and generate the necessary modified mesh files. Furthermore, the model geometry is fairly complex, and consistent mesh generation for the three physics modules required significant effort. Fully-integrated simulations of a 7-assembly mini-core test problem have been performed, and the results are presented here. Physics models of a full-core model of the Advanced Burner Test Reactor have also been developed for each of the three physics modules. Standalone results of each of the three physics modules for the ABTR are presented here, which provides a demonstration of the feasibility of the fully-integrated simulation.
Multiphysics Model of Palladium Hydride Isotope Exchange Accounting for Higher Dimensionality
Energy Technology Data Exchange (ETDEWEB)
Gharagozloo, Patricia E.; Eliassi, Mehdi; Bon, Bradley Luis
2015-03-01
This report summarizes computational model developm ent and simulations results for a series of isotope exchange dynamics experiments i ncluding long and thin isothermal beds similar to the Foltz and Melius beds and a lar ger non-isothermal experiment on the NENG7 test bed. The multiphysics 2D axi-symmetr ic model simulates the temperature and pressure dependent exchange reactio n kinetics, pressure and isotope dependent stoichiometry, heat generation from the r eaction, reacting gas flow through porous media, and non-uniformities in the bed perme ability. The new model is now able to replicate the curved reaction front and asy mmetry of the exit gas mass fractions over time. The improved understanding of the exchange process and its dependence on the non-uniform bed properties and te mperatures in these larger systems is critical to the future design of such sy stems.
DEFF Research Database (Denmark)
Lepech, Michael; Geiker, Mette; Michel, Alexander
This paper looks to address the grand challenge of integrating construction materials engineering research within a multi-scale, inter-disciplinary research and management framework for sustainable concrete infrastructure. The ultimate goal is to drive sustainability-focused innovation and adoption...... cycles in the broader architecture, engineering, construction (AEC) industry. Specifically, a probabilistic design framework for sustainable concrete infrastructure and a multi-physics service life model for reinforced concrete are presented as important points of integration for innovation between...... design, consists of concrete service life models and life cycle assessment (LCA) models. Both types of models (service life and LCA) are formulated stochastically so that the service life and time(s) to repair, as well as total sustainability impact, are described by a probability distribution. A central...
Kilbane, J.; Polzin, K. A.
2014-01-01
An annular linear induction pump (ALIP) that could be used for circulating liquid-metal coolant in a fission surface power reactor system is modeled in the present work using the computational COMSOL Multiphysics package. The pump is modeled using a two-dimensional, axisymmetric geometry and solved under conditions similar to those used during experimental pump testing. Real, nonlinear, temperature-dependent material properties can be incorporated into the model for both the electrically-conducting working fluid in the pump (NaK-78) and structural components of the pump. The intricate three-phase coil configuration of the pump is implemented in the model to produce an axially-traveling magnetic wave that is qualitatively similar to the measured magnetic wave. The model qualitatively captures the expected feature of a peak in efficiency as a function of flow rate.
Contribution to the study of multi-physical phenomena in cementitious materials
International Nuclear Information System (INIS)
Bary, B.
2010-09-01
This document is a synthesis of the applied research studies undertaken by the author during ten years, first at the University of Marne-La-Vallee during the period 1999-2002, then at the CEA. These studies concern the modeling and the numerical simulations of the cementitious materials behavior subjected on the one hand to moderate thermomechanical and hydric loadings, and on the other hand to chemical attacks due to the migration of calcium, carbonate and sulfate ions. The developed approaches may be viewed as multi-physical in the sense that the models used for describing the behavior couple various fields and phenomena such as mechanics, thermal, hydric and ionic transfers, and chemistry. In addition, analytical up-scaling techniques are applied to estimate the physical properties associated with these phenomena (mechanical, hydraulic and diffusive parameters) as a function of the microstructure and the hydric state of the material. (author)
Numerical methods for reliability and safety assessment multiscale and multiphysics systems
Hami, Abdelkhalak
2015-01-01
This book offers unique insight on structural safety and reliability by combining computational methods that address multiphysics problems, involving multiple equations describing different physical phenomena, and multiscale problems, involving discrete sub-problems that together describe important aspects of a system at multiple scales. The book examines a range of engineering domains and problems using dynamic analysis, nonlinear methods, error estimation, finite element analysis, and other computational techniques. This book also: · Introduces novel numerical methods · Illustrates new practical applications · Examines recent engineering applications · Presents up-to-date theoretical results · Offers perspective relevant to a wide audience, including teaching faculty/graduate students, researchers, and practicing engineers
Audigier, Chloé; Mansi, Tommaso; Delingette, Hervé; Rapaka, Saikiran; Passerini, Tiziano; Mihalef, Viorel; Jolly, Marie-Pierre; Pop, Raoul; Diana, Michele; Soler, Luc; Kamen, Ali; Comaniciu, Dorin; Ayache, Nicholas
2017-09-01
We aim at developing a framework for the validation of a subject-specific multi-physics model of liver tumor radiofrequency ablation (RFA). The RFA computation becomes subject specific after several levels of personalization: geometrical and biophysical (hemodynamics, heat transfer and an extended cellular necrosis model). We present a comprehensive experimental setup combining multimodal, pre- and postoperative anatomical and functional images, as well as the interventional monitoring of intra-operative signals: the temperature and delivered power. To exploit this dataset, an efficient processing pipeline is introduced, which copes with image noise, variable resolution and anisotropy. The validation study includes twelve ablations from five healthy pig livers: a mean point-to-mesh error between predicted and actual ablation extent of 5.3 ± 3.6 mm is achieved. This enables an end-to-end preclinical validation framework that considers the available dataset.
International Nuclear Information System (INIS)
Yue Liyang; Wang Zengbo; Li Lin
2012-01-01
Light could interact differently with thin-film contaminants and particle contaminates because of their different surface morphologies. In the case of dry laser cleaning of small transparent particles, it is well known that particles could function like mini-lenses, causing a localized near-field hot spot effect on the cleaning process. This paper looks into a special, yet important, phenomenon of dry laser cleaning of particles trapped in micro-sized slots. The effects of slot size, particle size and particle aggregate states in the cleaning process have been theoretically investigated, based on a coupled electromagnetic-thermal-mechanical multiphysics modelling and simulation approach. The study is important for the development and optimization of laser cleaning processes for contamination removal from cracks and slots. (paper)
Selection of High Performance Alloy for Gas Turbine Blade Using Multiphysics Analysis
Directory of Open Access Journals (Sweden)
H Khawaja
2016-09-01
Full Text Available With the extensive increase in the utilization of energy resources in the modern era, the need of energy extraction from various resources has pronounced in recent years. Thus comprehensive efforts have been made around the globe in the technological development of turbo machines where means of energy extraction is energized fluids. This development led the aviation industry to power boost due to better performing engines. Meanwhile, the structural conformability requirements relative to the functional requirements have also increased with the advent of newer, better performing materials. Thus there is a need to study the material behavior and its usage with the idea of selecting the best possible material for its application. In this work a gas turbine blade of a small turbofan engine, where geometry and aerodynamic data was available, was analyzed for its structural behavior in the proposed mission envelope, where the engine turbine is subjected to high thermal, inertial and aerodynamic loads. Multiphysics Finite Element (FE linear stress analysis was carried out on the turbine blade. The results revealed the upper limit of Ultimate Tensile Strength (UTS for the blade. Based on the limiting factor, high performance alloys were selected from the literature. The two most recommended alloy categories for gas turbine blades are NIMONIC and INCONEL from where total of 21 types of INCONEL alloys and 12 of NIMONIC alloys, available on commercial bases, were analyzed individually to meet the structural requirements. After applying selection criteria, four alloys were finalized from NIMONIC and INCONEL alloys for further analysis. On the basis of stress-strain behavior of finalized alloys, the Multiphysics FE nonlinear stress analysis was then carried out for the selection of the individual alloy by imposing a restriction of Ultimate Factor of Safety (UFOS of 1.33 and yield strength. Final selection is made keeping in view other factors
Integral Full Core Multi-Physics PWR Benchmark with Measured Data
Energy Technology Data Exchange (ETDEWEB)
Forget, Benoit; Smith, Kord; Kumar, Shikhar; Rathbun, Miriam; Liang, Jingang
2018-04-11
In recent years, the importance of modeling and simulation has been highlighted extensively in the DOE research portfolio with concrete examples in nuclear engineering with the CASL and NEAMS programs. These research efforts and similar efforts worldwide aim at the development of high-fidelity multi-physics analysis tools for the simulation of current and next-generation nuclear power reactors. Like all analysis tools, verification and validation is essential to guarantee proper functioning of the software and methods employed. The current approach relies mainly on the validation of single physic phenomena (e.g. critical experiment, flow loops, etc.) and there is a lack of relevant multiphysics benchmark measurements that are necessary to validate high-fidelity methods being developed today. This work introduces a new multi-cycle full-core Pressurized Water Reactor (PWR) depletion benchmark based on two operational cycles of a commercial nuclear power plant that provides a detailed description of fuel assemblies, burnable absorbers, in-core fission detectors, core loading and re-loading patterns. This benchmark enables analysts to develop extremely detailed reactor core models that can be used for testing and validation of coupled neutron transport, thermal-hydraulics, and fuel isotopic depletion. The benchmark also provides measured reactor data for Hot Zero Power (HZP) physics tests, boron letdown curves, and three-dimensional in-core flux maps from 58 instrumented assemblies. The benchmark description is now available online and has been used by many groups. However, much work remains to be done on the quantification of uncertainties and modeling sensitivities. This work aims to address these deficiencies and make this benchmark a true non-proprietary international benchmark for the validation of high-fidelity tools. This report details the BEAVRS uncertainty quantification for the first two cycle of operations and serves as the final report of the project.
Bouquerel, P; Gstalder, C; Müller, D; Laurent, J; Brizuela, L; Sabbadini, R A; Malavaud, B; Pyronnet, S; Martineau, Y; Ader, I; Cuvillier, O
2016-03-14
The sphingosine kinase-1/sphingosine 1-phosphate (SphK1/S1P) signaling pathway has been reported to modulate the expression of the canonical transcription factor hypoxia-inducible HIF-1α in multiple cell lineages. HIF-2α is also frequently overexpressed in solid tumors but its role has been mostly studied in clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, where HIF-2α has been established as a driver of a more aggressive disease. In this study, the role of SphK1/S1P signaling with regard to HIF-2α was investigated in various cancer cell models including ccRCC cells. Under hypoxic conditions or in ccRCC lacking a functional von Hippel-Lindau (VHL) gene and expressing high levels of HIF-2α, SphK1 activity controls HIF-2α expression and transcriptional activity through a phospholipase D (PLD)-driven mechanism. SphK1 silencing promotes a VHL-independent HIF-2α loss of expression and activity and reduces cell proliferation in ccRCC. Importantly, downregulation of SphK1 is associated with impaired Akt and mTOR signaling in ccRCC. Taking advantage of a monoclonal antibody neutralizing extracellular S1P, we show that inhibition of S1P extracellular signaling blocks HIF-2α accumulation in ccRCC cell lines, an effect mimicked when the S1P transporter Spns2 or the S1P receptor 1 (S1P1) is silenced. Here, we report the first evidence that the SphK1/S1P signaling pathway regulates the transcription factor hypoxia-inducible HIF-2α in diverse cancer cell lineages notably ccRCC, where HIF-2α has been established as a driver of a more aggressive disease. These findings demonstrate that SphK1/S1P signaling may act as a canonical regulator of HIF-2α expression in ccRCC, giving support to its inhibition as a therapeutic strategy that could contribute to reduce HIF-2 activity in ccRCC.
Energy Technology Data Exchange (ETDEWEB)
Bonaccorsi, Th
2007-09-15
A Material Testing Reactor (MTR) makes it possible to irradiate material samples under intense neutron and photonic fluxes. These experiments are carried out in experimental devices localised in the reactor core or in periphery (reflector). Available physics simulation tools only treat, most of the time, one physics field in a very precise way. Multi-physic simulations of irradiation experiments therefore require a sequential use of several calculation codes and data exchanges between these codes: this corresponds to problems coupling. In order to facilitate multi-physic simulations, this thesis sets up a data model based on data-processing objects, called Technological Entities. This data model is common to all of the physics fields. It permits defining the geometry of an irradiation device in a parametric way and to associate information about materials to it. Numerical simulations are encapsulated into interfaces providing the ability to call specific functionalities with the same command (to initialize data, to launch calculations, to post-treat, to get results,... ). Thus, once encapsulated, numerical simulations can be re-used for various studies. This data model is developed in a SALOME platform component. The first application case made it possible to perform neutronic simulations (OSIRIS reactor and RJH) coupled with fuel behavior simulations. In a next step, thermal hydraulics could also be taken into account. In addition to the improvement of the calculation accuracy due to the physical phenomena coupling, the time spent in the development phase of the simulation is largely reduced and the possibilities of uncertainty treatment are under consideration. (author)
Directory of Open Access Journals (Sweden)
Agnieszka Mikłosz
Full Text Available BACKGROUND: The objective of this study was to examine the effects of short (2 h and prolonged (18 h inhibition of serine palmitoyltransferase (SPT and sphingosine kinase 1 (SphK1 on palmitate (PA induced insulin resistance in L6 myotubes. METHODS: L6 myotubes were treated simultaneously with either PA and myriocin (SPT inhibitor or PA and Ski II (SphK1inhibitor for different time periods (2 h and 18 h. Insulin stimulated glucose uptake was measured using radioactive isotope. Expression of insulin signaling proteins was determined using Western blot analyses. Intracellular sphingolipids content [sphinganine (SFA, ceramide (CER, sphingosine (SFO, sphingosine-1-phosphate (S1P] were estimated by HPLC. RESULTS: Our results revealed that both short and prolonged time of inhibition of SPT by myriocin was sufficient to prevent ceramide accumulation and simultaneously reverse palmitate induced inhibition of insulin-stimulated glucose transport. In contrast, prolonged inhibition of SphK1 intensified the effect of PA on insulin-stimulated glucose uptake and attenuated further the activity of insulin signaling proteins (pGSK3β/GSK3β ratio in L6 myotubes. These effects were related to the accumulation of sphingosine in palmitate treated myotubes. CONCLUSION: Myriocin is more effective in restoration of palmitate induced insulin resistance in L6 myocytes, despite of the time of SPT inhibition, comparing to SKII (a specific SphK1 inhibitor. Observed changes in insulin signaling proteins were related to the content of specific sphingolipids, namely to the reduction of ceramide. Interestingly, inactivation of SphK1 augmented the effect of PA induced insulin resistance in L6 myotubes, which was associated with further inhibition of insulin stimulated PKB and GSK3β phosphorylation, glucose uptake and the accumulation of sphingosine.
Giusto, Kiersten; Ashby, Charles R
2018-01-30
Preterm birth (PTB), defined as birth before 37 completed weeks of gestation, occurs in up to 18 percent of births worldwide and accounts for the majority of perinatal morbidity and mortality. While the single most common cause of PTB has been identified as inflammation, safe and effective pharmacotherapy to prevent PTB has yet to be developed. Our group has used an in vivo model of inflammation driven PTB, biochemical methods, pharmacological approaches, a novel endothelin receptor antagonist that we synthesized and RNA knockdown to help establish the role of endothelin-1 (ET-1) in inflammation-associated PTB. Further, we have used our in vivo model to test whether sphingosine kinase, which acts downstream of ET-1, plays a role in PTB. We have shown that levels of endothelin converting enzyme-1 (ECE-1) and ET-1 are increased when PTB is induced in timed pregnant mice with lipopolysaccharide (LPS) and that blocking ET-1 action, pharmacologically or using ECE-1 RNA silencing, rescues LPS-induced mice from PTB. ET-1 activates the sphingosine kinase/sphingosine-1-phosphate (SphK/S1P) pathway. S1P, in turn, is an important signaling molecule in the pro-inflammatory response. Interestingly, we have shown that SphK inhibition also prevents LPS-induced PTB in timed pregnant mice. Further, we showed that SphK inhibition suppresses the ECE-1/ET-1 axis, implicating positive feedback regulation of the SphK/S1P/ECE-1/ET-1 axis. The ET-1/SphK/SIP pathway is a potential pharmacotherapeutic target for the prevention of PTB. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.
Matsunaga, James; Medeiros, Marco A; Sanchez, Yolanda; Werneid, Kristian F; Ko, Albert I
2007-10-01
The life cycle of the pathogen Leptospira interrogans involves stages outside and inside the host. Entry of L. interrogans from moist environments into the host is likely to be accompanied by the induction of genes encoding virulence determinants and the concomitant repression of genes encoding products required for survival outside of the host. The expression of the adhesin LigA, the haemolysin Sph2 (Lk73.5) and the outer-membrane lipoprotein LipL36 of pathogenic Leptospira species have been reported to be regulated by mammalian host signals. A previous study demonstrated that raising the osmolarity of the leptospiral growth medium to physiological levels encountered in the host by addition of various salts enhanced the levels of cell-associated LigA and LigB and extracellular LigA. In this study, we systematically examined the effects of osmotic upshift with ionic and non-ionic solutes on expression of the known mammalian host-regulated leptospiral genes. The levels of cell-associated LigA, LigB and Sph2 increased at physiological osmolarity, whereas LipL36 levels decreased, corresponding to changes in specific transcript levels. These changes in expression occurred irrespective of whether sodium chloride or sucrose was used as the solute. The increase of cellular LigA, LigB and Sph2 protein levels occurred within hours of adding sodium chloride. Extracellular Sph2 levels increased when either sodium chloride or sucrose was added to achieve physiological osmolarity. In contrast, enhanced levels of extracellular LigA were observed only with an increase in ionic strength. These results indicate that the mechanisms for release of LigA and Sph2 differ during host infection. Thus, osmolarity not only affects leptospiral gene expression by affecting transcript levels of putative virulence determinants but also affects the release of such proteins into the surroundings.
State of art in FE-based fuel performance codes
International Nuclear Information System (INIS)
Kim, Hyo Chan; Yang, Yong Sik; Kim, Dae Ho; Bang, Je Geon; Kim, Sun Ki; Koo, Yang Hyun
2013-01-01
Finite element (FE) method that is reliable and proven solution in mechanical field has been introduced into fuel performance codes for multidimensional analysis. The present state of the art in numerical simulation of FE-based fuel performance predominantly involves 2-D axisymmetric model and 3-D volumetric model. The FRAPCON and FRAPTRAN own 1.5-D and 2-D FE model to simulate PCMI and cladding ballooning. In 2-D simulation, the FALCON code, developed by EPRI, is a 2-D (R-Z and R-θ) fully thermal-mechanically coupled steady-state and transient FE-based fuel behavior code. The French codes TOUTATIS and ALCYONE which are 3-D, and typically used to investigate localized behavior. In 2008, the Idaho National Laboratory (INL) has been developing multidimensional (2-D and 3-D) nuclear fuel performance code called BISON. In this paper, the current state of FE-based fuel performance code and their models are presented. Based on investigation into the codes, requirements and direction of development for new FE-based fuel performance code can be discussed. Based on comparison of models in FE-based fuel performance code, status of art in the codes can be discussed. A new FE-based fuel performance code should include typical pellet and cladding models which all codes own. In particular, specified pellet and cladding model such as gaseous swelling and high burnup structure (HBS) model should be developed to improve accuracy of code as well as consider AC condition. To reduce computation cost, the approximated gap and the optimized contact model should be also developed. Nuclear fuel operates in an extreme environment that induces complex multiphysics phenomena, occurring over distances ranging from inter-atomic spacing to meters, and times scales ranging from microseconds to years. This multiphysics behavior is often tightly coupled, a well known example being the thermomechanical behavior. Adding to this complexity, important aspects of fuel behavior are inherently
Improvement of Parallel Algorithm for MATRA Code
International Nuclear Information System (INIS)
Kim, Seong-Jin; Seo, Kyong-Won; Kwon, Hyouk; Hwang, Dae-Hyun
2014-01-01
The feasibility study to parallelize the MATRA code was conducted in KAERI early this year. As a result, a parallel algorithm for the MATRA code has been developed to decrease a considerably required computing time to solve a bigsize problem such as a whole core pin-by-pin problem of a general PWR reactor and to improve an overall performance of the multi-physics coupling calculations. It was shown that the performance of the MATRA code was greatly improved by implementing the parallel algorithm using MPI communication. For problems of a 1/8 core and whole core for SMART reactor, a speedup was evaluated as about 10 when the numbers of used processor were 25. However, it was also shown that the performance deteriorated as the axial node number increased. In this paper, the procedure of a communication between processors is optimized to improve the previous parallel algorithm.. To improve the performance deterioration of the parallelized MATRA code, the communication algorithm between processors was newly presented. It was shown that the speedup was improved and stable regardless of the axial node number
Zainol, M. R. R. M. A.; Kamaruddin, M. A.; Zawawi, M. H.; Wahab, K. A.
2017-11-01
Smooth Particle Hydrodynamic is the three-dimensional (3D) model. In this research work, three cases and one validation have been simulate using DualSPHysics. Study area of this research work was at Sarawak Barrage. The cases have different water level at the downstream. This study actually to simulate riverbed erosion and scouring properties by using multi-phases cases which use sand as sediment and water. The velocity and the scouring profile have been recorded as the result and shown in the result chapter. The result of the validation is acceptable where the scouring profile and the velocity were slightly different between laboratory experiment and simulation. Hence, it can be concluded that the simulation by using SPH can be used as the alternative to simulate the real cases.
Comparing Results of SPH/N-body Impact Simulations Using Both Solid and Rubble-pile Target Asteroids
Durda, Daniel D.; Bottke, W. F.; Enke, B. L.; Nesvorný, D.; Asphaug, E.; Richardson, D. C.
2006-09-01
We have been investigating the properties of satellites and the morphology of size-frequency distributions (SFDs) resulting from a suite of 160 SPH/N-body simulations of impacts into 100-km diameter parent asteroids (Durda et al. 2004, Icarus 170, 243-257; Durda et al. 2006, Icarus, in press). These simulations have produced many valuable insights into the outcomes of cratering and disruptive impacts but were limited to monolithic basalt targets. As a natural consequence of collisional evolution, however, many asteroids have undergone a series of battering impacts that likely have left their interiors substantially fractured, if not completely rubblized. In light of this, we have re-mapped the matrix of simulations using rubble-pile target objects. We constructed the rubble-pile targets by filling the interior of the 100-km diameter spherical shell (the target envelope) with randomly sized solid spheres in mutual contact. We then assigned full damage (which reduces tensile and shear stresses to zero) to SPH particles in the contacts between the components; the remaining volume is void space. The internal spherical components have a power-law distribution of sizes simulating fragments of a pre-shattered parent object. First-look analysis of the rubble-pile results indicate some general similarities to the simulations with the monolithic targets (e.g., similar trends in the number of small, gravitationally bound satellite systems as a function of impact conditions) and some significant differences (e.g., size of largest remnants and smaller debris affecting size frequency distributions of resulting families). We will report details of a more thorough analysis and the implications for collisional models of the main asteroid belt. This work is supported by the National Science Foundation, grant number AST0407045.
Directory of Open Access Journals (Sweden)
V. V. Zelentsov
2017-01-01
Full Text Available Significant amount of space debris available in the near-Earth space is a reason to protect space vehicles from the fragments of space debris. Existing empirical calculation methods do not allow us to estimate quality of developed protection. Experimental verification of protection requires complex and expensive installations that do not allow having a desirable impact velocity. The article proposes to use the ANSYS AUTODYN software environment – a software complex of the nonlinear dynamic analysis to evaluate quality of developed protection. The ANSYS AUTODYN environment is based on the integration methods of a system of equations of continuum mechanics. The SPH (smoothed particle method method is used as a solver. The SPH method is based on the area of sampling by a finite set of the Lagrangian particles that can be represented as the elementary volumes of the medium. In modeling the targets were under attack of 2 and 3 mm spheres and cylinders with 2 mm in bottom diameter and with generator of 2 and 3 mm. The apheres and cylinders are solid and hollow, with a wall thickness of 0.5 mm. The impact velocity of the particles with a target was assumed to be 7.5 km / s. The number of integration cycles in all cases of calculation was assumed to be 1000. The rate of flying debris fragments of the target material as a function of the h / d ratio (h - the thickness of the target, / d - the diameter of a sphere or a cylinder end is obtained. In simulation the sample picture obtained coincides both with results of experimental study carried out at the Tomsk State Technical University and with results described in the literature.
Zhang, Jingyi
Ferroelectric (FE) and closely related antiferroelectric (AFE) materials have unique electromechanical properties that promote various applications in the area of capacitors, sensors, generators (FE) and high density energy storage (AFE). These smart materials with extensive applications have drawn wide interest in the industrial and scientific world because of their reliability and tunable property. However, reliability issues changes its paradigms and requires guidance from detailed mechanism theory as the materials applications are pushed for better performance. A host of modeling work were dedicated to study the macro-structural behavior and microstructural evolution in FE and AFE material under various conditions. This thesis is focused on direct observation of domain evolution under multiphysics loading for both FE and AFE material. Landau-Devonshire time-dependent phase field models were built for both materials, and were simulated in finite element software Comsol. In FE model, dagger-shape 90 degree switched domain was observed at preexisting crack tip under pure mechanical loading. Polycrystal structure was tested under same condition, and blocking effect of the growth of dagger-shape switched domain from grain orientation difference and/or grain boundary was directly observed. AFE ceramic model was developed using two sublattice theory, this model was used to investigate the mechanism of energy efficiency increase with self-confined loading in experimental tests. Consistent results was found in simulation and careful investigation of calculation results gave confirmation that origin of energy density increase is from three aspects: self-confinement induced inner compression field as the cause of increase of critical field, fringe leak as the source of elevated saturation polarization and uneven defects distribution as the reason for critical field shifting and phase transition speed. Another important affecting aspect in polycrystalline materials is the
DEFF Research Database (Denmark)
Cox, Geoff
Speaking Code begins by invoking the “Hello World” convention used by programmers when learning a new language, helping to establish the interplay of text and code that runs through the book. Interweaving the voice of critical writing from the humanities with the tradition of computing and software...
International Nuclear Information System (INIS)
Horrein, L.; Bouscayrol, A.; Cheng, Y.; El Fassi, M.
2015-01-01
Highlights: • Internal Combustion Engine (ICE) dynamical and static models. • Organization of ICE model using Energetic Macroscopic Representation. • Description of the distribution of the chemical, thermal and mechanical power. • Implementation of the ICE model in a global vehicle model. - Abstract: In the simulation of new vehicles, the Internal Combustion Engine (ICE) is generally modeled by a static map. This model yields the mechanical power and the fuel consumption. But some studies require the heat energy from the ICE to be considered (i.e. waste heat recovery, thermal regulation of the cabin). A dynamical multi-physical model of a diesel engine is developed to consider its heat energy. This model is organized using Energetic Macroscopic Representation (EMR) in order to be interconnected to other various models of vehicle subsystems. An experimental validation is provided. Moreover a multi-physical quasi-static model is also derived. According to different modeling aims, a comparison of the dynamical and the quasi-static model is discussed in the case of the simulation of a thermal vehicle. These multi-physical models with different simulation time consumption provide good basis for studying the effects of the thermal energy on the vehicle behaviors, including the possibilities of waste heat recovery
Two-Step Multi-Physics Analysis of an Annular Linear Induction Pump for Fission Power Systems
Geng, Steven M.; Reid, Terry V.
2016-01-01
One of the key technologies associated with fission power systems (FPS) is the annular linear induction pump (ALIP). ALIPs are used to circulate liquid-metal fluid for transporting thermal energy from the nuclear reactor to the power conversion device. ALIPs designed and built to date for FPS project applications have not performed up to expectations. A unique, two-step approach was taken toward the multi-physics examination of an ALIP using ANSYS Maxwell 3D and Fluent. This multi-physics approach was developed so that engineers could investigate design variations that might improve pump performance. Of interest was to determine if simple geometric modifications could be made to the ALIP components with the goal of increasing the Lorentz forces acting on the liquid-metal fluid, which in turn would increase pumping capacity. The multi-physics model first calculates the Lorentz forces acting on the liquid metal fluid in the ALIP annulus. These forces are then used in a computational fluid dynamics simulation as (a) internal boundary conditions and (b) source functions in the momentum equations within the Navier-Stokes equations. The end result of the two-step analysis is a predicted pump pressure rise that can be compared with experimental data.
Abdeljabbar Kharrat, Nourhene; Plateaux, Régis; Miladi Chaabane, Mariem; Choley, Jean-Yves; Karra, Chafik; Haddar, Mohamed
2018-05-01
The present work tackles the modeling of multi-physics systems applying a topological approach while proceeding with a new methodology using a topological modification to the structure of systems. Then the comparison with the Magos' methodology is made. Their common ground is the use of connectivity within systems. The comparison and analysis of the different types of modeling show the importance of the topological methodology through the integration of the topological modification to the topological structure of a multi-physics system. In order to validate this methodology, the case of Pogo-stick is studied. The first step consists in generating a topological graph of the system. Then the connectivity step takes into account the contact with the ground. During the last step of this research; the MGS language (Modeling of General System) is used to model the system through equations. Finally, the results are compared to those obtained by MODELICA. Therefore, this proposed methodology may be generalized to model multi-physics systems that can be considered as a set of local elements.
SIERRA Code Coupling Module: Arpeggio User Manual Version 4.44
Energy Technology Data Exchange (ETDEWEB)
Sierra Thermal/Fluid Team
2017-04-01
The SNL Sierra Mechanics code suite is designed to enable simulation of complex multiphysics scenarios. The code suite is composed of several specialized applications which can operate either in standalone mode or coupled with each other. Arpeggio is a supported utility that enables loose coupling of the various Sierra Mechanics applications by providing access to Framework services that facilitate the coupling. More importantly Arpeggio orchestrates the execution of applications that participate in the coupling. This document describes the various components of Arpeggio and their operability. The intent of the document is to provide a fast path for analysts interested in coupled applications via simple examples of its usage.
Interfacial mixing in high-energy-density matter with a multiphysics kinetic model
Haack, Jeffrey R.; Hauck, Cory D.; Murillo, Michael S.
2017-12-01
We have extended a recently developed multispecies, multitemperature Bhatnagar-Gross-Krook model [Haack et al., J. Stat. Phys. 168, 822 (2017), 10.1007/s10955-017-1824-9], to include multiphysics capabilities that enable modeling of a wider range of physical conditions. In terms of geometry, we have extended from the spatially homogeneous setting to one spatial dimension. In terms of the physics, we have included an atomic ionization model, accurate collision physics across coupling regimes, self-consistent electric fields, and degeneracy in the electronic screening. We apply the model to a warm dense matter scenario in which the ablator-fuel interface of an inertial confinement fusion target is heated, but for larger length and time scales and for much higher temperatures than can be simulated using molecular dynamics. Relative to molecular dynamics, the kinetic model greatly extends the temperature regime and the spatiotemporal scales over which we are able to model. In our numerical results we observe hydrogen from the ablator material jetting into the fuel during the early stages of the implosion and compare the relative size of various diffusion components (Fickean diffusion, electrodiffusion, and barodiffusion) that drive this process. We also examine kinetic effects, such as anisotropic distributions and velocity separation, in order to determine when this problem can be described with a hydrodynamic model.
Experimental multiphysical characterization of an SMA driven, camber morphing owl wing section
Stroud, Hannah R.; Leal, Pedro B. C.; Hartl, Darren J.
2018-03-01
In the context of aerospace engineering, morphing structures are useful in their ability to change the outer mold line (OML) while improving or maintaining certain aerodynamic performance metrics. Skin-based morphing is of particular interest in that it minimizes installation volume. Shape memory alloys (SMAs) have a high force to volume ratio that makes them a suitable choice for skin-based morphing. Because the thermomechanical properties of SMAs are coupled, strain can be generated via a temperature variation; this phenomenon is used as the actuation method. Therefore, it is necessary to determine the interaction of the system not only with aerodynamic loads, but with thermal loads as well. This paper describes the wind tunnel testing and in situ thermomechanical analysis of an SMA actuated, avian inspired morphing wing. The morphing wing is embedded with two SMA composite actuators and consists of a foam core enveloped in a fiberglass-epoxy composite. As the SMA wire is heated, the actuator contracts, morphing the wing from the original owl OML to a highly cambered, high lift OML. Configuration characteristics are analyzed in situ using simultaneous three dimensional digital image correlation (DIC) and infrared thermography, thereby coupling strain and thermal measurements. This method of testing allows for the nonintrusive, multiphysical data acquisition of each actuator separately and the system as a whole.
Propagation of neutron-reaction uncertainties through multi-physics models of novel LWR's
Directory of Open Access Journals (Sweden)
Hernandez-Solis Augusto
2017-01-01
Full Text Available The novel design of the renewable boiling water reactor (RBWR allows a breeding ratio greater than unity and thus, it aims at providing for a self-sustained fuel cycle. The neutron reactions that compose the different microscopic cross-sections and angular distributions are uncertain, so when they are employed in the determination of the spatial distribution of the neutron flux in a nuclear reactor, a methodology should be employed to account for these associated uncertainties. In this work, the Total Monte Carlo (TMC method is used to propagate the different neutron-reactions (as well as angular distributions covariances that are part of the TENDL-2014 nuclear data (ND library. The main objective is to propagate them through coupled neutronic and thermal-hydraulic models in order to assess the uncertainty of important safety parameters related to multi-physics, such as peak cladding temperature along the axial direction of an RBWR fuel assembly. The objective of this study is to quantify the impact that ND covariances of important nuclides such as U-235, U-238, Pu-239 and the thermal scattering of hydrogen in H2O have in the deterministic safety analysis of novel nuclear reactors designs.
Using COMSOL Multiphysics Software to Analyze the Thin Film Resistance Model of a Conductor on PET
Carradero-Santiago, Carolyn; Merced-Sanabria, Milzaida; Vedrine-Pauléus, Josee
2015-03-01
In this research work, we will develop a virtual model to analyze the electrical conductivity of a thin film with three layers, one of graphene or conducting metal film, polyethylene terephthalate (PET) and Poly(3,4-ethylenedioxythiophene) Polystyrene sulfonate (PEDOT:PSS). COMSOL Multiphysics will be the software use to develop the virtual model to analyze the thin-film layers. COMSOL software allows simulation and modelling of physical phenomena represented by differential equations such as that of heat transfer, fluid movement, electromagnetism and structural mechanics. In the work, we will define the geometry of the model; in this case we want three layers-PET, the conducting layer and PEDOT:PSS. We will then add the materials and assign PET as the lower layer, the above conductor as the middle layer and the PEDOT:PSS as the upper layer. We will analyze the model with varying thickness of the top conducting layer. This simulation will allow us to analyze the electrical conductivity, and visualize the model with varying voltage potential, or bias across the plates.
Varghese, Julian
This research work has contributed in various ways to help develop a better understanding of textile composites and materials with complex microstructures in general. An instrumental part of this work was the development of an object-oriented framework that made it convenient to perform multiscale/multiphysics analyses of advanced materials with complex microstructures such as textile composites. In addition to the studies conducted in this work, this framework lays the groundwork for continued research of these materials. This framework enabled a detailed multiscale stress analysis of a woven DCB specimen that revealed the effect of the complex microstructure on the stress and strain energy release rate distribution along the crack front. In addition to implementing an oxidation model, the framework was also used to implement strategies that expedited the simulation of oxidation in textile composites so that it would take only a few hours. The simulation showed that the tow architecture played a significant role in the oxidation behavior in textile composites. Finally, a coupled diffusion/oxidation and damage progression analysis was implemented that was used to study the mechanical behavior of textile composites under mechanical loading as well as oxidation. A parametric study was performed to determine the effect of material properties and the number of plies in the laminate on its mechanical behavior. The analyses indicated a significant effect of the tow architecture and other parameters on the damage progression in the laminates.
Directory of Open Access Journals (Sweden)
Jiazhou Wu
2018-06-01
Full Text Available A three-dimensional multiphysical transient model was developed to investigate keyhole formation, weld pool dynamics, and mass transfer in laser welding of dissimilar materials. The coupling of heat transfer, fluid flow, keyhole free surface evolution, and solute diffusion between dissimilar metals was simulated. The adaptive heat source model was used to trace the change of keyhole shape, and the Rayleigh scattering of the laser beam was considered. The keyhole wall was calculated using the fluid volume equation, primarily considering the recoil pressure induced by metal evaporation, surface tension, and hydrostatic pressure. Fluid flow, diffusion, and keyhole formation were considered simultaneously in mass transport processes. Welding experiments of 304L stainless steel and industrial pure titanium TA2 were performed to verify the simulation results. It is shown that spatters are shaped during the welding process. The thickness of the intermetallic reaction layer between the two metals and the diffusion of elements in the weld are calculated, which are important criteria for welding quality. The simulation results correspond well with the experimental results.
Fovargue, Daniel E; Mitran, Sorin; Smith, Nathan B; Sankin, Georgy N; Simmons, Walter N; Zhong, Pei
2013-08-01
A multiphysics computational model of the focusing of an acoustic pulse and subsequent shock wave formation that occurs during extracorporeal shock wave lithotripsy is presented. In the electromagnetic lithotripter modeled in this work the focusing is achieved via a polystyrene acoustic lens. The transition of the acoustic pulse through the solid lens is modeled by the linear elasticity equations and the subsequent shock wave formation in water is modeled by the Euler equations with a Tait equation of state. Both sets of equations are solved simultaneously in subsets of a single computational domain within the BEARCLAW framework which uses a finite-volume Riemann solver approach. This model is first validated against experimental measurements with a standard (or original) lens design. The model is then used to successfully predict the effects of a lens modification in the form of an annular ring cut. A second model which includes a kidney stone simulant in the domain is also presented. Within the stone the linear elasticity equations incorporate a simple damage model.
MahmoodPoorDehkordy, F.; Briggs, M. A.; Day-Lewis, F. D.; Bagtzoglou, A. C.
2017-12-01
Although hyporheic zones are often modeled at the reach scale as homogeneous "boxes" of exchange, heterogeneity caused by variations of pore sizes and connectivity is not uncommon. This heterogeneity leads to the creation of more- and less-mobile zones of hydraulic exchange that influence reactive solute transport processes. Whereas fluid sampling is generally sensitive to more-mobile zones, geoelectrical measurement is sensitive to ionic tracer dynamics in both less- and more-mobile zones. Heterogeneity in pore connectivity leads to a lag between fluid and bulk electrical conductivity (EC) resulting in a hysteresis loop, observed during tracer breakthrough tests, that contains information about the less-mobile porosity attributes of the medium. Here, we present a macro-scale model of solute transport and electrical conduction developed using COMSOL Multiphysics. The model is used to simulate geoelectrical monitoring of ionic transport for bed sediments based on (1) a stochastic sand-and-cobble mixture and (2) a dune feature with strong permeability layering. In both of these disparate sediment types, hysteresis between fluid and bulk EC is observed, and depends in part on fluid flux rate through the model domain. Using the hysteresis loop, the ratio of less-mobile to mobile porosity and mass-transfer coefficient are estimated graphically. The results indicate the presence and significance of less-mobile porosity in the hyporheic zones and demonstrate the capability of the proposed model to detect heterogeneity in flow processes and estimate less-mobile zone parameters.
A multiphysics and multiscale model for low frequency electromagnetic direct-chill casting
International Nuclear Information System (INIS)
Košnik, N; Guštin, A Z; Mavrič, B; Šarler, B
2016-01-01
Simulation and control of macrosegregation, deformation and grain size in low frequency electromagnetic (EM) direct-chill casting (LFEMC) is important for downstream processing. Respectively, a multiphysics and multiscale model is developed for solution of Lorentz force, temperature, velocity, concentration, deformation and grain structure of LFEMC processed aluminum alloys, with focus on axisymmetric billets. The mixture equations with lever rule, linearized phase diagram, and stationary thermoelastic solid phase are assumed, together with EM induction equation for the field imposed by the coil. Explicit diffuse approximate meshless solution procedure [1] is used for solving the EM field, and the explicit local radial basis function collocation method [2] is used for solving the coupled transport phenomena and thermomechanics fields. Pressure-velocity coupling is performed by the fractional step method [3]. The point automata method with modified KGT model is used to estimate the grain structure [4] in a post-processing mode. Thermal, mechanical, EM and grain structure outcomes of the model are demonstrated. A systematic study of the complicated influences of the process parameters can be investigated by the model, including intensity and frequency of the electromagnetic field. The meshless solution framework, with the implemented simplest physical models, will be further extended by including more sophisticated microsegregation and grain structure models, as well as a more realistic solid and solid-liquid phase rheology. (paper)
International Nuclear Information System (INIS)
Yang, Xiaobin; Li, Xiuhong; He, Yafeng; Wang, Xiaojun; Xu, Bo
2017-01-01
Highlights: • The differential equation including temperature and magnetic field was derived for a long cylindrical superconductor. • Thermal stress and electromagnetic stress were studied at the same time under pulse field magnetizing. • The distributions of the magnetic field, the temperature and stresses are studied and compared for two pulse fields of the different duration. • The Role thermal stress and electromagnetic stress play in the process of pulse field magnetizing is discussed. - Abstract: A multiphysics model for the numerical computation of stresses, trapped field and temperature distribution of a infinite long superconducting cylinder is proposed, based on which the stresses, including the thermal stresses and mechanical stresses due to Lorentz force, and trapped fields in the superconductor subjected to pulsed magnetic fields are analyzed. By comparing the results under pulsed magnetic fields with different pulse durations, it is found that the both the mechanical stress due to the electromagnetic force and the thermal stress due to temperature gradient contribute to the total stress level in the superconductor. For pulsed magnetic field with short durations, the thermal stress is the dominant contribution to the total stress, because the heat generated by AC-loss builds up significant temperature gradient in such short durations. However, for a pulsed field with a long duration the gradient of temperature and flux, as well as the maximal tensile stress, are much smaller. And the results of this paper is meaningful for the design and manufacture of superconducting permanent magnets.
Li, Hua; Wang, Xiaogui; Yan, Guoping; Lam, K. Y.; Cheng, Sixue; Zou, Tao; Zhuo, Renxi
2005-03-01
In this paper, a novel multiphysic mathematical model is developed for simulation of swelling equilibrium of ionized temperature sensitive hydrogels with the volume phase transition, and it is termed the multi-effect-coupling thermal-stimulus (MECtherm) model. This model consists of the steady-state Nernst-Planck equation, Poisson equation and swelling equilibrium governing equation based on the Flory's mean field theory, in which two types of polymer-solvent interaction parameters, as the functions of temperature and polymer-network volume fraction, are specified with or without consideration of the hydrogen bond interaction. In order to examine the MECtherm model consisting of nonlinear partial differential equations, a meshless Hermite-Cloud method is used for numerical solution of one-dimensional swelling equilibrium of thermal-stimulus responsive hydrogels immersed in a bathing solution. The computed results are in very good agreements with experimental data for the variation of volume swelling ratio with temperature. The influences of the salt concentration and initial fixed-charge density are discussed in detail on the variations of volume swelling ratio of hydrogels, mobile ion concentrations and electric potential of both interior hydrogels and exterior bathing solution.
A tightly-coupled domain-decomposition approach for highly nonlinear stochastic multiphysics systems
Energy Technology Data Exchange (ETDEWEB)
Taverniers, Søren; Tartakovsky, Daniel M., E-mail: dmt@ucsd.edu
2017-02-01
Multiphysics simulations often involve nonlinear components that are driven by internally generated or externally imposed random fluctuations. When used with a domain-decomposition (DD) algorithm, such components have to be coupled in a way that both accurately propagates the noise between the subdomains and lends itself to a stable and cost-effective temporal integration. We develop a conservative DD approach in which tight coupling is obtained by using a Jacobian-free Newton–Krylov (JfNK) method with a generalized minimum residual iterative linear solver. This strategy is tested on a coupled nonlinear diffusion system forced by a truncated Gaussian noise at the boundary. Enforcement of path-wise continuity of the state variable and its flux, as opposed to continuity in the mean, at interfaces between subdomains enables the DD algorithm to correctly propagate boundary fluctuations throughout the computational domain. Reliance on a single Newton iteration (explicit coupling), rather than on the fully converged JfNK (implicit) coupling, may increase the solution error by an order of magnitude. Increase in communication frequency between the DD components reduces the explicit coupling's error, but makes it less efficient than the implicit coupling at comparable error levels for all noise strengths considered. Finally, the DD algorithm with the implicit JfNK coupling resolves temporally-correlated fluctuations of the boundary noise when the correlation time of the latter exceeds some multiple of an appropriately defined characteristic diffusion time.
A templated approach for multi-physics modeling of hybrid energy systems in Modelica
Energy Technology Data Exchange (ETDEWEB)
Greenwood, Michael Scott [ORNL; Cetiner, Sacit M. [ORNL; Harrison, Thomas J. [ORNL; Fugate, David [Oak Ridge National Laboratory (ORNL)
2018-01-01
A prototypical hybrid energy system (HES) couples a primary thermal power generator (i.e., nuclear power plant) with one or more additional subsystems beyond the traditional balance of plant electricity generation system. The definition and architecture of an HES can be adapted based on the needs and opportunities of a given local market. For example, locations in need of potable water may be best served by coupling a desalination plant to the HES. A location near an oil refinery may have a need for emission-free hydrogen production. The flexible, multidomain capabilities of Modelica are being used to investigate the dynamics (e.g., thermal hydraulics and electrical generation/consumption) of such a hybrid system. This paper examines the simulation infrastructure created to enable the coupling of multiphysics subsystem models for HES studies. A demonstration of a tightly coupled nuclear hybrid energy system implemented using the Modelica based infrastructure is presented for two representative cases. An appendix is also included providing a step-by-step procedure for using the template-based infrastructure.
Directory of Open Access Journals (Sweden)
Jiajia Zheng
2014-02-01
Full Text Available A novel magnetorheological (MR damper with a multistage piston and independent input currents is designed and analyzed. The equivalent magnetic circuit model is investigated along with the relation between magnetic induction density in the working gap and input currents of the electromagnetic coils. Finite element method (FEM is used to analyze the distribution of magnetic field through the MR fluid region. Considering the real situation, coupling equations are presented to analyze the electromagnetic-thermal-flow coupling problems. Software COMSOL is used to analyze the multiphysics, that is, electromagnetic, thermal dynamic, and fluid mechanic. A measurement index involving total damping force, dynamic range, and induction time needed for magnetic coil is put forward to evaluate the performance of the novel multistage MR damper. The simulation results show that it is promising for applications under high velocity and works better when more electromagnetic coils are applied with input currents separately. Besides, in order to reduce energy consumption, it is recommended to apply more electromagnetic coils with relative low currents based on the analysis of pressure drop along the annular gap.
Design of a Modular Monolithic Implicit Solver for Multi-Physics Applications
Carton De Wiart, Corentin; Diosady, Laslo T.; Garai, Anirban; Burgess, Nicholas; Blonigan, Patrick; Ekelschot, Dirk; Murman, Scott M.
2018-01-01
The design of a modular multi-physics high-order space-time finite-element framework is presented together with its extension to allow monolithic coupling of different physics. One of the main objectives of the framework is to perform efficient high- fidelity simulations of capsule/parachute systems. This problem requires simulating multiple physics including, but not limited to, the compressible Navier-Stokes equations, the dynamics of a moving body with mesh deformations and adaptation, the linear shell equations, non-re effective boundary conditions and wall modeling. The solver is based on high-order space-time - finite element methods. Continuous, discontinuous and C1-discontinuous Galerkin methods are implemented, allowing one to discretize various physical models. Tangent and adjoint sensitivity analysis are also targeted in order to conduct gradient-based optimization, error estimation, mesh adaptation, and flow control, adding another layer of complexity to the framework. The decisions made to tackle these challenges are presented. The discussion focuses first on the "single-physics" solver and later on its extension to the monolithic coupling of different physics. The implementation of different physics modules, relevant to the capsule/parachute system, are also presented. Finally, examples of coupled computations are presented, paving the way to the simulation of the full capsule/parachute system.
Energy Technology Data Exchange (ETDEWEB)
Yang, Xiaobin, E-mail: yangxb@lzu.edu.cn; Li, Xiuhong; He, Yafeng; Wang, Xiaojun; Xu, Bo
2017-04-15
Highlights: • The differential equation including temperature and magnetic field was derived for a long cylindrical superconductor. • Thermal stress and electromagnetic stress were studied at the same time under pulse field magnetizing. • The distributions of the magnetic field, the temperature and stresses are studied and compared for two pulse fields of the different duration. • The Role thermal stress and electromagnetic stress play in the process of pulse field magnetizing is discussed. - Abstract: A multiphysics model for the numerical computation of stresses, trapped field and temperature distribution of a infinite long superconducting cylinder is proposed, based on which the stresses, including the thermal stresses and mechanical stresses due to Lorentz force, and trapped fields in the superconductor subjected to pulsed magnetic fields are analyzed. By comparing the results under pulsed magnetic fields with different pulse durations, it is found that the both the mechanical stress due to the electromagnetic force and the thermal stress due to temperature gradient contribute to the total stress level in the superconductor. For pulsed magnetic field with short durations, the thermal stress is the dominant contribution to the total stress, because the heat generated by AC-loss builds up significant temperature gradient in such short durations. However, for a pulsed field with a long duration the gradient of temperature and flux, as well as the maximal tensile stress, are much smaller. And the results of this paper is meaningful for the design and manufacture of superconducting permanent magnets.
González-Fernández, Bárbara; Sánchez, Diana I; Crespo, Irene; San-Miguel, Beatriz; Álvarez, Marcelino; Tuñón, María J; González-Gallego, Javier
2017-03-01
The sphingosine kinase 1/sphingosine 1-phosphate (SphK1/S1P) system is involved in different pathological processes, including fibrogenesis. Melatonin abrogates activation of hepatic stellate cells (HSCs) and attenuates different profibrogenic pathways in animal models of fibrosis, but it is unknown if protection associates with its inhibitory effect on the SphK1/S1P axis. Mice in treatment groups received carbon tetrachloride (CCl 4 ) 5 μL g -1 body wt i.p. twice a week for 4 or 6 weeks. Melatonin was given at 5 or 10 mg kg -1 day -1 i.p, beginning 2 weeks after the start of CCl 4 administration. At both 4 and 6 weeks following CCl 4 treatment, liver mRNA levels, protein concentration and immunohistochemical labelling for SphK1 increased significantly. S1P production, and expression of S1P receptor (S1PR)1, S1PR3 and acid sphingomyelinase (ASMase) were significantly elevated. However, there was a decreased expression of S1PR2 and S1P lyase (S1PL). Melatonin attenuated liver fibrosis, as shown by a significant inhibition of the expression of α-smooth muscle actin (α-SMA), transforming growth factor (TGF)-β and collagen (Col) Ι. Furthermore, melatonin inhibited S1P production, lowered expression of SphK1, S1PR1, SP1R3, and ASMase, and increased expression of S1PL. Melatonin induced a reversal of activated human HSCs cell line LX2, as evidenced by a reduction in α-SMA, TGF-β, and Col I expression. Melatonin-treated cells also exhibited an inhibition of the SphK1/S1P axis. Antifibrogenic effect of SphK1 inhibition was confirmed by treatment of LX2 cells with PF543. Abrogation of the lipid signaling pathway by the indole reveals novel molecular pathways that may account for the protective effect of melatonin in liver fibrogenesis. © 2016 BioFactors, 43(2):272-282, 2017. © 2016 International Union of Biochemistry and Molecular Biology.
Sandalski, Stou
Smooth particle hydrodynamics is an efficient method for modeling the dynamics of fluids. It is commonly used to simulate astrophysical processes such as binary mergers. We present a newly developed GPU accelerated smooth particle hydrodynamics code for astrophysical simulations. The code is named neptune after the Roman god of water. It is written in OpenMP parallelized C++ and OpenCL and includes octree based hydrodynamic and gravitational acceleration. The design relies on object-oriented methodologies in order to provide a flexible and modular framework that can be easily extended and modified by the user. Several pre-built scenarios for simulating collisions of polytropes and black-hole accretion are provided. The code is released under the MIT Open Source license and publicly available at http://code.google.com/p/neptune-sph/.
Directory of Open Access Journals (Sweden)
Anthony McCosker
2014-03-01
Full Text Available As well as introducing the Coding Labour section, the authors explore the diffusion of code across the material contexts of everyday life, through the objects and tools of mediation, the systems and practices of cultural production and organisational management, and in the material conditions of labour. Taking code beyond computation and software, their specific focus is on the increasingly familiar connections between code and labour with a focus on the codification and modulation of affect through technologies and practices of management within the contemporary work organisation. In the grey literature of spreadsheets, minutes, workload models, email and the like they identify a violence of forms through which workplace affect, in its constant flux of crisis and ‘prodromal’ modes, is regulated and governed.
StarSmasher: Smoothed Particle Hydrodynamics code for smashing stars and planets
Gaburov, Evghenii; Lombardi, James C., Jr.; Portegies Zwart, Simon; Rasio, F. A.
2018-05-01
Smoothed Particle Hydrodynamics (SPH) is a Lagrangian particle method that approximates a continuous fluid as discrete nodes, each carrying various parameters such as mass, position, velocity, pressure, and temperature. In an SPH simulation the resolution scales with the particle density; StarSmasher is able to handle both equal-mass and equal number-density particle models. StarSmasher solves for hydro forces by calculating the pressure for each particle as a function of the particle's properties - density, internal energy, and internal properties (e.g. temperature and mean molecular weight). The code implements variational equations of motion and libraries to calculate the gravitational forces between particles using direct summation on NVIDIA graphics cards. Using a direct summation instead of a tree-based algorithm for gravity increases the accuracy of the gravity calculations at the cost of speed. The code uses a cubic spline for the smoothing kernel and an artificial viscosity prescription coupled with a Balsara Switch to prevent unphysical interparticle penetration. The code also implements an artificial relaxation force to the equations of motion to add a drag term to the calculated accelerations during relaxation integrations. Initially called StarCrash, StarSmasher was developed originally by Rasio.
de Vries, Hendrik J; Marshall, Ian P G; Schreiber, Lars; Plugge, Caroline M
2017-06-15
We report here the high-quality draft genome sequence of Sphingomonas sp. strain Sph1(2015), isolated from a fouled reverse osmosis membrane used for the production of high-quality drinking water. The draft sequence provides insights into the modus operandi of this strain to form biofilms on membrane surfaces. This knowledge offers tools to develop novel antifouling strategies. Copyright © 2017 de Vries et al.
Nagahashi, Masayuki; Yamada, Akimitsu; Katsuta, Eriko; Aoyagi, Tomoyoshi; Huang, Wei-Ching; Terracina, Krista P; Hait, Nitai C; Allegood, Jeremy C; Tsuchida, Junko; Yuza, Kizuki; Nakajima, Masato; Abe, Manabu; Sakimura, Kenji; Milstien, Sheldon; Wakai, Toshifumi; Spiegel, Sarah; Takabe, Kazuaki
2018-04-01
Although obesity with associated inflammation is now recognized as a risk factor for breast cancer and distant metastases, the functional basis for these connections remain poorly understood. Here, we show that in breast cancer patients and in animal breast cancer models, obesity is a sufficient cause for increased expression of the bioactive sphingolipid mediator sphingosine-1-phosphate (S1P), which mediates cancer pathogenesis. A high-fat diet was sufficient to upregulate expression of sphingosine kinase 1 (SphK1), the enzyme that produces S1P, along with its receptor S1PR1 in syngeneic and spontaneous breast tumors. Targeting the SphK1/S1P/S1PR1 axis with FTY720/fingolimod attenuated key proinflammatory cytokines, macrophage infiltration, and tumor progression induced by obesity. S1P produced in the lung premetastatic niche by tumor-induced SphK1 increased macrophage recruitment into the lung and induced IL6 and signaling pathways important for lung metastatic colonization. Conversely, FTY720 suppressed IL6, macrophage infiltration, and S1P-mediated signaling pathways in the lung induced by a high-fat diet, and it dramatically reduced formation of metastatic foci. In tumor-bearing mice, FTY720 similarly reduced obesity-related inflammation, S1P signaling, and pulmonary metastasis, thereby prolonging survival. Taken together, our results establish a critical role for circulating S1P produced by tumors and the SphK1/S1P/S1PR1 axis in obesity-related inflammation, formation of lung metastatic niches, and breast cancer metastasis, with potential implications for prevention and treatment. Significance: These findings offer a preclinical proof of concept that signaling by a sphingolipid may be an effective target to prevent obesity-related breast cancer metastasis. Cancer Res; 78(7); 1713-25. ©2018 AACR . ©2018 American Association for Cancer Research.
Lollino, Piernicola; Giordan, Daniele; Allasia, Paolo; Pastor, Manuel
2016-04-01
. The SPH numerical results of the Montaguto earthflow propagation seem to be in good agreement with the field observations in terms of both movement direction, run-out distance and thickness of the debris soil mass. The modelling results confirm that these landslide processes can be efficiently modelled by means of the SPH numerical technique, providing that a soil rheology capable of taking into account the main features of the soil behavior that affect the earthflow mobility is used.
Nimmala, Praneeth Reddy; Theivendran, Shevanuja; Barcaro, Giovanni; Sementa, Luca; Kumara, Chanaka; Jupally, Vijay Reddy; Apra, Edoardo; Stener, Mauro; Fortunelli, Alessandro; Dass, Amala
2015-06-04
Ultrastable gold nanomolecule Au144(SCH2CH2Ph)60 upon etching with excess tert-butylbenzenethiol undergoes a core-size conversion and compositional change to form an entirely new core of Au133(SPh-tBu)52. This conversion was studied using high-resolution electrospray mass spectrometry which shows that the core size conversion is initiated after 22 ligand exchanges, suggesting a relatively high stability of the Au144(SCH2CH2Ph)38(SPh-tBu)22 intermediate. The Au144 → Au133 core size conversion is surprisingly different from the Au144 → Au99 core conversion reported in the case of thiophenol, -SPh. Theoretical analysis and ab initio molecular dynamics simulations show that rigid p-tBu groups play a crucial role by reducing the cluster structural freedom, and protecting the cluster from adsorption of exogenous and reactive species, thus rationalizing the kinetic factors that stabilize the Au133 core size. This 144-atom to 133-atom nanomolecule's compositional change is reflected in optical spectroscopy and electrochemistry.
Crespo, Irene; San-Miguel, Beatriz; Mauriz, José Luis; Ortiz de Urbina, Juan José; Almar, Mar; Tuñón, María Jesús; González-Gallego, Javier
2017-03-16
(1) Background: The present study aimed to investigate whether beneficial effects of protocatechuic acid (PCA) are associated with inhibition of the SphK/S1P axis and related signaling pathways in a 2,4,6-trinitrobenzenesulfonic acid (TNBS) model of inflammatory bowel disease; (2) Methods: Colitis was induced in male Balb/c mice by intracolonic administration of 2 mg of TNBS. PCA (30 or 60 mg/kg body wt) was given intraperitoneally daily for five days; (3) Results: Administration of PCA prevented the macroscopic and microscopic damage to the colonic mucosa, the decrease in body weight gain and the increase in myeloperoxidase activity induced by TNBS. PCA-treated mice exhibited a lower oxidized/reduced glutathione ratio, increased expression of antioxidant enzymes and Nrf2 and reduced expression of proinflammatory cytokines. Following TNBS treatment mRNA levels, protein concentration and immunohistochemical labelling for SphK1 increased significantly. S1P production and expression of S1P receptor 1 and S1P phosphatase 2 were significantly elevated. However, there was a decreased expression of S1P lyase. Furthermore, TNBS-treated mice exhibited increased phosphorylation of AKT and ERK, and a higher expression of pSTAT3 and the NF-κB p65 subunit. PCA administration significantly prevented those changes; (4) Conclusions: Data obtained suggest a contribution of the SphK/S1P system and related signaling pathways to the anti-inflammatory effect of PCA.
Geng, Tuoyu; Sutter, Alton; Harland, Michael D; Law, Brittany A; Ross, Jessica S; Lewin, David; Palanisamy, Arun; Russo, Sarah B; Chavin, Kenneth D; Cowart, L Ashley
2015-12-01
Steatohepatitis occurs in up to 20% of patients with fatty liver disease and leads to its primary disease outcomes, including fibrosis, cirrhosis, and increased risk of hepatocellular carcinoma. Mechanisms that mediate this inflammation are of major interest. We previously showed that overload of saturated fatty acids, such as that which occurs with metabolic syndrome, induced sphingosine kinase 1 (SphK1), an enzyme that generates sphingosine-1-phosphate (S1P). While data suggest beneficial roles for S1P in some contexts, we hypothesized that it may promote hepatic inflammation in the context of obesity. Consistent with this, we observed 2-fold elevation of this enzyme in livers from humans with nonalcoholic fatty liver disease and also in mice with high saturated fat feeding, which recapitulated the human disease. Mice exhibited activation of NFκB, elevated cytokine production, and immune cell infiltration. Importantly, SphK1-null mice were protected from these outcomes. Studies in cultured cells demonstrated saturated fatty acid induction of SphK1 message, protein, and activity, and also a requirement of the enzyme for NFκB signaling and increased mRNA encoding TNFα and MCP1. Moreover, saturated fat-induced NFκB signaling and elevation of TNFα and MCP1 mRNA in HepG2 cells was blocked by targeted knockdown of S1P receptor 1, supporting a role for this lipid signaling pathway in inflammation in nonalcoholic fatty liver disease.
Malan, Frederick P.; Singleton, Eric; van Rooyen, Petrus H.; Conradie, Jeanet; Landman, Marilé
2017-11-01
The synthesis, density functional theory (DFT) conformational study and structure analysis of novel two-legged piano stool Ni N-heterocyclic carbene (NHC) complexes and square planar Ni bis-N-heterocyclic carbene complexes, all containing either bromido- or thiophenolato ligands, are described. [CpNi(SPh)(NHC)] complexes were obtained from the neutral 18-electron [CpNiBr(NHC)] complexes by substitution of a bromido ligand with SPh, using NEt3 as a base to abstract the proton of HSPh. The 16-electron biscarbene complexes [Ni(SPh)2{NHC}2] were isolated when an excess of HSPh was added to the reaction mixture. Biscarbene complexes of the type [NiBr2(NHC)2] were obtained in the reaction of NiCp2 with a slight excess of the specific imidazolium bromide salt. The molecular and electronic structures of the mono- and bis-N-heterocyclic carbene complexes have been analysed using single crystal diffraction and density functional theory (DFT) calculations, to give insight into their structural properties.
Atomistic to Continuum Multiscale and Multiphysics Simulation of NiTi Shape Memory Alloy
Gur, Sourav
(transformation temperature, phase fraction evolution kinetics due to temperature) are also demonstrated herein. Next, to couple and transfer the statistical information of length scale dependent phase transformation process, multiscale/ multiphysics methods are used. Here, the computational difficulty from the fact that the representative governing equations (i.e. different sub-methods such as molecular dynamics simulations, phase field simulations and continuum level constitutive/ material models) are only valid or can be implemented over a range of spatiotemporal scales. Therefore, in the present study, a wavelet based multiscale coupling method is used, where simulation results (phase fraction evolution kinetics) from different sub-methods are linked via concurrent multiscale coupling fashion. Finally, these multiscale/ multiphysics simulation results are used to develop/ modify the macro/ continuum scale thermo-mechanical constitutive relations for NiTi SMA. Finally, the improved material model is used to model new devices, such as thermal diodes and smart dampers.
Energy Technology Data Exchange (ETDEWEB)
Ravishankar, C., Hughes Network Systems, Germantown, MD
1998-05-08
Speech is the predominant means of communication between human beings and since the invention of the telephone by Alexander Graham Bell in 1876, speech services have remained to be the core service in almost all telecommunication systems. Original analog methods of telephony had the disadvantage of speech signal getting corrupted by noise, cross-talk and distortion Long haul transmissions which use repeaters to compensate for the loss in signal strength on transmission links also increase the associated noise and distortion. On the other hand digital transmission is relatively immune to noise, cross-talk and distortion primarily because of the capability to faithfully regenerate digital signal at each repeater purely based on a binary decision. Hence end-to-end performance of the digital link essentially becomes independent of the length and operating frequency bands of the link Hence from a transmission point of view digital transmission has been the preferred approach due to its higher immunity to noise. The need to carry digital speech became extremely important from a service provision point of view as well. Modem requirements have introduced the need for robust, flexible and secure services that can carry a multitude of signal types (such as voice, data and video) without a fundamental change in infrastructure. Such a requirement could not have been easily met without the advent of digital transmission systems, thereby requiring speech to be coded digitally. The term Speech Coding is often referred to techniques that represent or code speech signals either directly as a waveform or as a set of parameters by analyzing the speech signal. In either case, the codes are transmitted to the distant end where speech is reconstructed or synthesized using the received set of codes. A more generic term that is applicable to these techniques that is often interchangeably used with speech coding is the term voice coding. This term is more generic in the sense that the
Optimal codes as Tanner codes with cyclic component codes
DEFF Research Database (Denmark)
Høholdt, Tom; Pinero, Fernando; Zeng, Peng
2014-01-01
In this article we study a class of graph codes with cyclic code component codes as affine variety codes. Within this class of Tanner codes we find some optimal binary codes. We use a particular subgraph of the point-line incidence plane of A(2,q) as the Tanner graph, and we are able to describe ...
A Multiphysics Framework to Learn and Predict in Presence of Multiple Scales
Tomin, P.; Lunati, I.
2015-12-01
Modeling complex phenomena in the subsurface remains challenging due to the presence of multiple interacting scales, which can make it impossible to focus on purely macroscopic phenomena (relevant in most applications) and neglect the processes at the micro-scale. We present and discuss a general framework that allows us to deal with the situation in which the lack of scale separation requires the combined use of different descriptions at different scale (for instance, a pore-scale description at the micro-scale and a Darcy-like description at the macro-scale) [1,2]. The method is based on conservation principles and constructs the macro-scale problem by numerical averaging of micro-scale balance equations. By employing spatiotemporal adaptive strategies, this approach can efficiently solve large-scale problems [2,3]. In addition, being based on a numerical volume-averaging paradigm, it offers a tool to illuminate how macroscopic equations emerge from microscopic processes, to better understand the meaning of microscopic quantities, and to investigate the validity of the assumptions routinely used to construct the macro-scale problems. [1] Tomin, P., and I. Lunati, A Hybrid Multiscale Method for Two-Phase Flow in Porous Media, Journal of Computational Physics, 250, 293-307, 2013 [2] Tomin, P., and I. Lunati, Local-global splitting and spatiotemporal-adaptive Multiscale Finite Volume Method, Journal of Computational Physics, 280, 214-231, 2015 [3] Tomin, P., and I. Lunati, Spatiotemporal adaptive multiphysics simulations of drainage-imbibition cycles, Computational Geosciences, 2015 (under review)
A self-taught artificial agent for multi-physics computational model personalization.
Neumann, Dominik; Mansi, Tommaso; Itu, Lucian; Georgescu, Bogdan; Kayvanpour, Elham; Sedaghat-Hamedani, Farbod; Amr, Ali; Haas, Jan; Katus, Hugo; Meder, Benjamin; Steidl, Stefan; Hornegger, Joachim; Comaniciu, Dorin
2016-12-01
Personalization is the process of fitting a model to patient data, a critical step towards application of multi-physics computational models in clinical practice. Designing robust personalization algorithms is often a tedious, time-consuming, model- and data-specific process. We propose to use artificial intelligence concepts to learn this task, inspired by how human experts manually perform it. The problem is reformulated in terms of reinforcement learning. In an off-line phase, Vito, our self-taught artificial agent, learns a representative decision process model through exploration of the computational model: it learns how the model behaves under change of parameters. The agent then automatically learns an optimal strategy for on-line personalization. The algorithm is model-independent; applying it to a new model requires only adjusting few hyper-parameters of the agent and defining the observations to match. The full knowledge of the model itself is not required. Vito was tested in a synthetic scenario, showing that it could learn how to optimize cost functions generically. Then Vito was applied to the inverse problem of cardiac electrophysiology and the personalization of a whole-body circulation model. The obtained results suggested that Vito could achieve equivalent, if not better goodness of fit than standard methods, while being more robust (up to 11% higher success rates) and with faster (up to seven times) convergence rate. Our artificial intelligence approach could thus make personalization algorithms generalizable and self-adaptable to any patient and any model. Copyright © 2016. Published by Elsevier B.V.
Multiphysics modeling of two-phase film boiling within porous corrosion deposits
Energy Technology Data Exchange (ETDEWEB)
Jin, Miaomiao, E-mail: mmjin@mit.edu; Short, Michael, E-mail: hereiam@mit.edu
2016-07-01
Porous corrosion deposits on nuclear fuel cladding, known as CRUD, can cause multiple operational problems in light water reactors (LWRs). CRUD can cause accelerated corrosion of the fuel cladding, increase radiation fields and hence greater exposure risk to plant workers once activated, and induce a downward axial power shift causing an imbalance in core power distribution. In order to facilitate a better understanding of CRUD's effects, such as localized high cladding surface temperatures related to accelerated corrosion rates, we describe an improved, fully-coupled, multiphysics model to simulate heat transfer, chemical reactions and transport, and two-phase fluid flow within these deposits. Our new model features a reformed assumption of 2D, two-phase film boiling within the CRUD, correcting earlier models' assumptions of single-phase coolant flow with wick boiling under high heat fluxes. This model helps to better explain observed experimental values of the effective CRUD thermal conductivity. Finally, we propose a more complete set of boiling regimes, or a more detailed mechanism, to explain recent CRUD deposition experiments by suggesting the new concept of double dryout specifically in thick porous media with boiling chimneys. - Highlights: • A two-phase model of CRUD's effects on fuel cladding is developed and improved. • This model eliminates the formerly erroneous assumption of wick boiling. • Higher fuel cladding temperatures are predicted when accounting for two-phase flow. • Double-peaks in thermal conductivity vs. heat flux in experiments are explained. • A “double dryout” mechanism in CRUD is proposed based on the model and experiments.
International Nuclear Information System (INIS)
Quezada G, S.; Espinosa P, G.; Centeno P, J.; Sanchez M, H.
2017-09-01
This paper presents the Aztheca code, which is formed by the mathematical models of neutron kinetics, power generation, heat transfer, core thermo-hydraulics, recirculation systems, dynamic pressure and level models and control system. The Aztheca code is validated with plant data, as well as with predictions from the manufacturer when the reactor operates in a stationary state. On the other hand, to demonstrate that the model is applicable during a transient, an event occurred in a nuclear power plant with a BWR reactor is selected. The plant data are compared with the results obtained with RELAP-5 and the Aztheca model. The results show that both RELAP-5 and the Aztheca code have the ability to adequately predict the behavior of the reactor. (Author)
DEFF Research Database (Denmark)
Soon, Winnie; Cox, Geoff
2018-01-01
a computational and poetic composition for two screens: on one of these, texts and voices are repeated and disrupted by mathematical chaos, together exploring the performativity of code and language; on the other, is a mix of a computer programming syntax and human language. In this sense queer code can...... be understood as both an object and subject of study that intervenes in the world’s ‘becoming' and how material bodies are produced via human and nonhuman practices. Through mixing the natural and computer language, this article presents a script in six parts from a performative lecture for two persons...
International Nuclear Information System (INIS)
Rattan, D.S.
1993-11-01
NSURE stands for Near-Surface Repository code. NSURE is a performance assessment code. developed for the safety assessment of near-surface disposal facilities for low-level radioactive waste (LLRW). Part one of this report documents the NSURE model, governing equations and formulation of the mathematical models, and their implementation under the SYVAC3 executive. The NSURE model simulates the release of nuclides from an engineered vault, their subsequent transport via the groundwater and surface water pathways tot he biosphere, and predicts the resulting dose rate to a critical individual. Part two of this report consists of a User's manual, describing simulation procedures, input data preparation, output and example test cases
Directory of Open Access Journals (Sweden)
Khaled Sadek
2009-10-01
Full Text Available In this paper, the reliability of capacitive shunt RF MEMS switches have been investigated using three dimensional (3D coupled multiphysics finite element (FE analysis. The coupled field analysis involved three consecutive multiphysics interactions. The first interaction is characterized as a two-way sequential electromagnetic (EM-thermal field coupling. The second interaction represented a one-way sequential thermal-structural field coupling. The third interaction portrayed a two-way sequential structural-electrostatic field coupling. An automated substructuring algorithm was utilized to reduce the computational cost of the complicated coupled multiphysics FE analysis. The results of the substructured FE model with coupled field analysis is shown to be in good agreement with the outcome of previously published experimental and numerical studies. The current numerical results indicate that the pull-in voltage and the buckling temperature of the RF switch are functions of the microfabrication residual stress state, the switch operational frequency and the surrounding packaging temperature. Furthermore, the current results point out that by introducing proper mechanical approaches such as corrugated switches and through-holes in the switch membrane, it is possible to achieve reliable pull-in voltages, at various operating temperatures. The performed analysis also shows that by controlling the mean and gradient residual stresses, generated during microfabrication, in conjunction with the proposed mechanical approaches, the power handling capability of RF MEMS switches can be increased, at a wide range of operational frequencies. These design features of RF MEMS switches are of particular importance in applications where a high RF power (frequencies above 10 GHz and large temperature variations are expected, such as in satellites and airplane condition monitoring.
Energy Technology Data Exchange (ETDEWEB)
Delbecq, J.M
1999-07-01
The Aster code is a 2D or 3D finite-element calculation code for structures developed by the R and D direction of Electricite de France (EdF). This dossier presents a complete overview of the characteristics and uses of the Aster code: introduction of version 4; the context of Aster (organisation of the code development, versions, systems and interfaces, development tools, quality assurance, independent validation); static mechanics (linear thermo-elasticity, Euler buckling, cables, Zarka-Casier method); non-linear mechanics (materials behaviour, big deformations, specific loads, unloading and loss of load proportionality indicators, global algorithm, contact and friction); rupture mechanics (G energy restitution level, restitution level in thermo-elasto-plasticity, 3D local energy restitution level, KI and KII stress intensity factors, calculation of limit loads for structures), specific treatments (fatigue, rupture, wear, error estimation); meshes and models (mesh generation, modeling, loads and boundary conditions, links between different modeling processes, resolution of linear systems, display of results etc..); vibration mechanics (modal and harmonic analysis, dynamics with shocks, direct transient dynamics, seismic analysis and aleatory dynamics, non-linear dynamics, dynamical sub-structuring); fluid-structure interactions (internal acoustics, mass, rigidity and damping); linear and non-linear thermal analysis; steels and metal industry (structure transformations); coupled problems (internal chaining, internal thermo-hydro-mechanical coupling, chaining with other codes); products and services. (J.S.)
SuPer-Homogenization (SPH) Corrected Cross Section Generation for High Temperature Reactor
Energy Technology Data Exchange (ETDEWEB)
Sen, Ramazan Sonat [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hummel, Andrew John [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hiruta, Hikaru [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2017-03-01
The deterministic full core simulators require homogenized group constants covering the operating and transient conditions over the entire lifetime. Traditionally, the homogenized group constants are generated using lattice physics code over an assembly or block in the case of prismatic high temperature reactors (HTR). For the case of strong absorbers that causes strong local depressions on the flux profile require special techniques during homogenization over a large volume. Fuel blocks with burnable poisons or control rod blocks are example of such cases. Over past several decades, there have been a tremendous number of studies performed for improving the accuracy of full-core calculations through the homogenization procedure. However, those studies were mostly performed for light water reactor (LWR) analyses, thus, may not be directly applicable to advanced thermal reactors such as HTRs. This report presents the application of SuPer-Homogenization correction method to a hypothetical HTR core.
International Nuclear Information System (INIS)
Yoshimura, Shinobu; Kawai, Hiroshi; Sugimoto, Shin'ichiro; Hori, Muneo; Nakajima, Norihiro; Kobayashi, Kei
2010-01-01
Recently importance of nuclear energy has been recognized again due to serious concerns of global warming and energy security. In parallel, it is one of critical issues to verify safety capability of ageing nuclear power plants (NPPs) subjected to strong earthquake. Since 2007, we have been developing the multi-scale and multi-physics based numerical simulator for quantitatively predicting actual quake-proof capability of ageing NPPs under operation or just after plant trip subjected to strong earthquake. In this paper, we describe an overview of the simulator with some preliminary results. (author)
International Nuclear Information System (INIS)
Sanchez, Victor Hugo; Miassoedov, Alexei; Steinbrueck, M.; Tromm, W.
2016-01-01
This paper describes the KIT numerical simulation tools under extension and validation for the analysis of design and beyond design basis accidents (DBA) of Light Water Reactors (LWR). The description of the complex thermal hydraulic, neutron kinetics and chemo-physical phenomena going on during off-normal conditions requires the development of multi-physics and multi-scale simulations tools which are fostered by the rapid increase in computer power nowadays. The KIT numerical tools for DBA and beyond DBA are validated using experimental data of KIT or from abroad. The developments, extensions, coupling approaches and validation work performed at KIT are shortly outlined and discussed in this paper.
Energy Technology Data Exchange (ETDEWEB)
Sanchez, Victor Hugo; Miassoedov, Alexei; Steinbrueck, M.; Tromm, W. [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (Germany)
2016-05-15
This paper describes the KIT numerical simulation tools under extension and validation for the analysis of design and beyond design basis accidents (DBA) of Light Water Reactors (LWR). The description of the complex thermal hydraulic, neutron kinetics and chemo-physical phenomena going on during off-normal conditions requires the development of multi-physics and multi-scale simulations tools which are fostered by the rapid increase in computer power nowadays. The KIT numerical tools for DBA and beyond DBA are validated using experimental data of KIT or from abroad. The developments, extensions, coupling approaches and validation work performed at KIT are shortly outlined and discussed in this paper.
DEFF Research Database (Denmark)
Ejsing-Duun, Stine; Hansbøl, Mikala
Denne rapport rummer evaluering og dokumentation af Coding Class projektet1. Coding Class projektet blev igangsat i skoleåret 2016/2017 af IT-Branchen i samarbejde med en række medlemsvirksomheder, Københavns kommune, Vejle Kommune, Styrelsen for IT- og Læring (STIL) og den frivillige forening...... Coding Pirates2. Rapporten er forfattet af Docent i digitale læringsressourcer og forskningskoordinator for forsknings- og udviklingsmiljøet Digitalisering i Skolen (DiS), Mikala Hansbøl, fra Institut for Skole og Læring ved Professionshøjskolen Metropol; og Lektor i læringsteknologi, interaktionsdesign......, design tænkning og design-pædagogik, Stine Ejsing-Duun fra Forskningslab: It og Læringsdesign (ILD-LAB) ved Institut for kommunikation og psykologi, Aalborg Universitet i København. Vi har fulgt og gennemført evaluering og dokumentation af Coding Class projektet i perioden november 2016 til maj 2017...
Andrews, Ken; Divsalar, Dariush; Dolinar, Sam; Moision, Bruce; Hamkins, Jon; Pollara, Fabrizio
2007-01-01
This slide presentation reviews the objectives, meeting goals and overall NASA goals for the NASA Data Standards Working Group. The presentation includes information on the technical progress surrounding the objective, short LDPC codes, and the general results on the Pu-Pw tradeoff.
International Nuclear Information System (INIS)
Lindemuth, I.R.
1979-01-01
This report describes ANIMAL, a two-dimensional Eulerian magnetohydrodynamic computer code. ANIMAL's physical model also appears. Formulated are temporal and spatial finite-difference equations in a manner that facilitates implementation of the algorithm. Outlined are the functions of the algorithm's FORTRAN subroutines and variables
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Network Coding. K V Rashmi Nihar B Shah P Vijay Kumar. General Article Volume 15 Issue 7 July 2010 pp 604-621. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/015/07/0604-0621 ...
International Nuclear Information System (INIS)
Cramer, S.N.
1984-01-01
The MCNP code is the major Monte Carlo coupled neutron-photon transport research tool at the Los Alamos National Laboratory, and it represents the most extensive Monte Carlo development program in the United States which is available in the public domain. The present code is the direct descendent of the original Monte Carlo work of Fermi, von Neumaum, and Ulam at Los Alamos in the 1940s. Development has continued uninterrupted since that time, and the current version of MCNP (or its predecessors) has always included state-of-the-art methods in the Monte Carlo simulation of radiation transport, basic cross section data, geometry capability, variance reduction, and estimation procedures. The authors of the present code have oriented its development toward general user application. The documentation, though extensive, is presented in a clear and simple manner with many examples, illustrations, and sample problems. In addition to providing the desired results, the output listings give a a wealth of detailed information (some optional) concerning each state of the calculation. The code system is continually updated to take advantage of advances in computer hardware and software, including interactive modes of operation, diagnostic interrupts and restarts, and a variety of graphical and video aids
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 1. Expander Codes - The Sipser–Spielman Construction. Priti Shankar. General Article Volume 10 ... Author Affiliations. Priti Shankar1. Department of Computer Science and Automation, Indian Institute of Science Bangalore 560 012, India.
SALOME. A software integration platform for multi-physics, pre-processing and visualisation
International Nuclear Information System (INIS)
Bergeaud, Vincent; Lefebvre, Vincent
2010-01-01
In order to ease the development of applications integrating simulation codes, CAD modelers and post-processing tools. CEA and EDF R and D have invested in the SALOME platform, a tool dedicated to the environment of the scientific codes. The platform comes in the shape of a toolbox which offers functionalities for CAD, meshing, code coupling, visualization, GUI development. These tools can be combined to create integrated applications that make the scientific codes easier to use and well-interfaced with their environment be it other codes, CAD and meshing tools or visualization software. Many projects in CEA and EDF R and D now use SALOME, bringing technical coherence to the software suites of our institutions. (author)
International Nuclear Information System (INIS)
Huang, J H; Wang, X J; Wang, J
2016-01-01
The primary purpose of this paper is to propose a mathematical model of PLZT ceramic with coupled multi-physics fields, e.g. thermal, electric, mechanical and light field. To this end, the coupling relationships of multi-physics fields and the mechanism of some effects resulting in the photostrictive effect are analyzed theoretically, based on which a mathematical model considering coupled multi-physics fields is established. According to the analysis and experimental results, the mathematical model can explain the hysteresis phenomenon and the variation trend of the photo-induced voltage very well and is in agreement with the experimental curves. In addition, the PLZT bimorph is applied as an energy transducer for a photovoltaic–electrostatic hybrid actuated micromirror, and the relation of the rotation angle and the photo-induced voltage is discussed based on the novel photostrictive mathematical model. (paper)
Code development for nuclear reactor simulation
International Nuclear Information System (INIS)
Chauliac, C.; Verwaerde, D.; Pavageau, O.
2006-01-01
Full text of publication follows: Since several years, CEA, EDF and FANP have developed several numerical codes which are currently used for nuclear industry applications and will be remain in use for the coming years. Complementary to this set of codes and in order to better meet the present and future needs, a new system is being developed through a joint venture between CEA, EDF and FANP, with a ten year prospect and strong intermediate milestones. The focus is put on a multi-scale and multi-physics approach enabling to take into account phenomena from microscopic to macroscopic scale, and to describe interactions between various physical fields such as neutronics (DESCARTES), thermal-hydraulics (NEPTUNE) and fuel behaviour (PLEIADES). This approach is based on a more rational design of the softwares and uses a common integration platform providing pre-processing, supervision of computation and post-processing. This paper will describe the overall system under development and present the first results obtained. (authors)
Design and Analysis of a New Hair Sensor for Multi-Physical Signal Measurement
Directory of Open Access Journals (Sweden)
Bo Yang
2016-07-01
Full Text Available A new hair sensor for multi-physical signal measurements, including acceleration, angular velocity and air flow, is presented in this paper. The entire structure consists of a hair post, a torsional frame and a resonant signal transducer. The hair post is utilized to sense and deliver the physical signals of the acceleration and the air flow rate. The physical signals are converted into frequency signals by the resonant transducer. The structure is optimized through finite element analysis. The simulation results demonstrate that the hair sensor has a frequency of 240 Hz in the first mode for the acceleration or the air flow sense, 3115 Hz in the third and fourth modes for the resonant conversion, and 3467 Hz in the fifth and sixth modes for the angular velocity transformation, respectively. All the above frequencies present in a reasonable modal distribution and are separated from interference modes. The input-output analysis of the new hair sensor demonstrates that the scale factor of the acceleration is 12.35 Hz/g, the scale factor of the angular velocity is 0.404 nm/deg/s and the sensitivity of the air flow is 1.075 Hz/(m/s2, which verifies the multifunction sensitive characteristics of the hair sensor. Besides, the structural optimization of the hair post is used to improve the sensitivity of the air flow rate and the acceleration. The analysis results illustrate that the hollow circular hair post can increase the sensitivity of the air flow and the II-shape hair post can increase the sensitivity of the acceleration. Moreover, the thermal analysis confirms the scheme of the frequency difference for the resonant transducer can prominently eliminate the temperature influences on the measurement accuracy. The air flow analysis indicates that the surface area increase of hair post is significantly beneficial for the efficiency improvement of the signal transmission. In summary, the structure of the new hair sensor is proved to be feasible by
Multi-scale and multi-physics model of the uterine smooth muscle with mechanotransduction.
Yochum, Maxime; Laforêt, Jérémy; Marque, Catherine
2018-02-01
Preterm labor is an important public health problem. However, the efficiency of the uterine muscle during labor is complex and still poorly understood. This work is a first step towards a model of the uterine muscle, including its electrical and mechanical components, to reach a better understanding of the uterus synchronization. This model is proposed to investigate, by simulation, the possible role of mechanotransduction for the global synchronization of the uterus. The electrical diffusion indeed explains the local propagation of contractile activity, while the tissue stretching may play a role in the synchronization of distant parts of the uterine muscle. This work proposes a multi-physics (electrical, mechanical) and multi-scales (cell, tissue, whole uterus) model, which is applied to a realistic uterus 3D mesh. This model includes electrical components at different scales: generation of action potentials at the cell level, electrical diffusion at the tissue level. It then links these electrical events to the mechanical behavior, at the cellular level (via the intracellular calcium concentration), by simulating the force generated by each active cell. It thus computes an estimation of the intra uterine pressure (IUP) by integrating the forces generated by each active cell at the whole uterine level, as well as the stretching of the tissue (by using a viscoelastic law for the behavior of the tissue). It finally includes at the cellular level stretch activated channels (SACs) that permit to create a loop between the mechanical and the electrical behavior (mechanotransduction). The simulation of different activated regions of the uterus, which in this first "proof of concept" case are electrically isolated, permits the activation of inactive regions through the stretching (induced by the electrically active regions) computed at the whole organ scale. This permits us to evidence the role of the mechanotransduction in the global synchronization of the uterus. The
Size and density sorting of dust grains in SPH simulations of protoplanetary discs
Pignatale, F. C.; Gonzalez, J.-F.; Cuello, Nicolas; Bourdon, Bernard; Fitoussi, Caroline
2017-07-01
The size and density of dust grains determine their response to gas drag in protoplanetary discs. Aerodynamical (size × density) sorting is one of the proposed mechanisms to explain the grain properties and chemical fractionation of chondrites. However, the efficiency of aerodynamical sorting and the location in the disc in which it could occur are still unknown. Although the effects of grain sizes and growth in discs have been widely studied, a simultaneous analysis including dust composition is missing. In this work, we present the dynamical evolution and growth of multicomponent dust in a protoplanetary disc using a 3D, two-fluid (gas+dust) smoothed particle hydrodynamics code. We find that the dust vertical settling is characterized by two phases: a density-driven phase that leads to a vertical chemical sorting of dust and a size-driven phase that enhances the amount of lighter material in the mid-plane. We also see an efficient radial chemical sorting of the dust at large scales. We find that dust particles are aerodynamically sorted in the inner disc. The disc becomes sub-solar in its Fe/Si ratio on the surface since the early stage of evolution but sub-solar Fe/Si can be also found in the outer disc-mid-plane at late stages. Aggregates in the disc mimic the physical and chemical properties of chondrites, suggesting that aerodynamical sorting played an important role in determining their final structure.
International Nuclear Information System (INIS)
Altomare, S.; Minton, G.
1975-02-01
PANDA is a new two-group one-dimensional (slab/cylinder) neutron diffusion code designed to replace and extend the FAB series. PANDA allows for the nonlinear effects of xenon, enthalpy and Doppler. Fuel depletion is allowed. PANDA has a completely general search facility which will seek criticality, maximize reactivity, or minimize peaking. Any single parameter may be varied in a search. PANDA is written in FORTRAN IV, and as such is nearly machine independent. However, PANDA has been written with the present limitations of the Westinghouse CDC-6600 system in mind. Most computation loops are very short, and the code is less than half the useful 6600 memory size so that two jobs can reside in the core at once. (auth)
International Nuclear Information System (INIS)
Gara, P.; Martin, E.
1983-01-01
The CANAL code presented here optimizes a realistic iron free extraction channel which has to provide a given transversal magnetic field law in the median plane: the current bars may be curved, have finite lengths and cooling ducts and move in a restricted transversal area; terminal connectors may be added, images of the bars in pole pieces may be included. A special option optimizes a real set of circular coils [fr
Directory of Open Access Journals (Sweden)
D Cébron
2016-04-01
Full Text Available The present paper is concerned with the numerical simulation of Magneto-Hydro-Dynamic (MHD problems with industrial tools. MHD has receivedattention some twenty to thirty years ago as a possible alternative inpropulsion applications; MHD propelled ships have even been designed forthat purpose. However, such propulsion systems have been proved of lowefficiency and fundamental researches in the area have progressivelyreceived much less attention over the past decades. Numerical simulationof MHD problem could however provide interesting solutions in the field ofturbulent flow control. The development of recent efficient numericaltechniques for multi-physic applications provide promising tool for theengineer for that purpose. In the present paper, some elementary testcases in laminar flow with magnetic forcing terms are analysed; equationsof the coupled problem are exposed, analytical solutions are derived ineach case and are compared to numerical solutions obtained with anumerical tool for multi-physic applications. The present work can be seenas a validation of numerical tools (based on the finite element method foracademic as well as industrial application purposes.
Poulet, Thomas; Paesold, Martin; Veveakis, Manolis
2017-03-01
Faults play a major role in many economically and environmentally important geological systems, ranging from impermeable seals in petroleum reservoirs to fluid pathways in ore-forming hydrothermal systems. Their behavior is therefore widely studied and fault mechanics is particularly focused on the mechanisms explaining their transient evolution. Single faults can change in time from seals to open channels as they become seismically active and various models have recently been presented to explain the driving forces responsible for such transitions. A model of particular interest is the multi-physics oscillator of Alevizos et al. (J Geophys Res Solid Earth 119(6), 4558-4582, 2014) which extends the traditional rate and state friction approach to rate and temperature-dependent ductile rocks, and has been successfully applied to explain spatial features of exposed thrusts as well as temporal evolutions of current subduction zones. In this contribution we implement that model in REDBACK, a parallel open-source multi-physics simulator developed to solve such geological instabilities in three dimensions. The resolution of the underlying system of equations in a tightly coupled manner allows REDBACK to capture appropriately the various theoretical regimes of the system, including the periodic and non-periodic instabilities. REDBACK can then be used to simulate the drastic permeability evolution in time of such systems, where nominally impermeable faults can sporadically become fluid pathways, with permeability increases of several orders of magnitude.
Suzuki, Yuma; Shimizu, Tetsuhide; Yang, Ming
2017-01-01
The quantitative evaluation of the biomolecules transport with multi-physics in nano/micro scale is demanded in order to optimize the design of microfluidics device for the biomolecules detection with high detection sensitivity and rapid diagnosis. This paper aimed to investigate the effectivity of the computational simulation using the numerical model of the biomolecules transport with multi-physics near a microchannel surface on the development of biomolecules-detection devices. The biomolecules transport with fluid drag force, electric double layer (EDL) force, and van der Waals force was modeled by Newtonian Equation of motion. The model validity was verified in the influence of ion strength and flow velocity on biomolecules distribution near the surface compared with experimental results of previous studies. The influence of acting forces on its distribution near the surface was investigated by the simulation. The trend of its distribution to ion strength and flow velocity was agreement with the experimental result by the combination of all acting forces. Furthermore, EDL force dominantly influenced its distribution near its surface compared with fluid drag force except for the case of high velocity and low ion strength. The knowledges from the simulation might be useful for the design of biomolecules-detection devices and the simulation can be expected to be applied on its development as the design tool for high detection sensitivity and rapid diagnosis in the future.
Konishi, Toshifumi; Yamane, Daisuke; Matsushima, Takaaki; Masu, Kazuya; Machida, Katsuyuki; Toshiyoshi, Hiroshi
2014-01-01
This paper reports the design and evaluation results of a capacitive CMOS-MEMS sensor that consists of the proposed sensor circuit and a capacitive MEMS device implemented on the circuit. To design a capacitive CMOS-MEMS sensor, a multi-physics simulation of the electromechanical behavior of both the MEMS structure and the sensing LSI was carried out simultaneously. In order to verify the validity of the design, we applied the capacitive CMOS-MEMS sensor to a MEMS accelerometer implemented by the post-CMOS process onto a 0.35-µm CMOS circuit. The experimental results of the CMOS-MEMS accelerometer exhibited good agreement with the simulation results within the input acceleration range between 0.5 and 6 G (1 G = 9.8 m/s2), corresponding to the output voltages between 908.6 and 915.4 mV, respectively. Therefore, we have confirmed that our capacitive CMOS-MEMS sensor and the multi-physics simulation will be beneficial method to realize integrated CMOS-MEMS technology.
Zheng, Jiajia; Li, Yancheng; Li, Zhaochun; Wang, Jiong
2015-10-01
This paper presents multi-physics modeling of an MR absorber considering the magnetic hysteresis to capture the nonlinear relationship between the applied current and the generated force under impact loading. The magnetic field, temperature field, and fluid dynamics are represented by the Maxwell equations, conjugate heat transfer equations, and Navier-Stokes equations. These fields are coupled through the apparent viscosity and the magnetic force, both of which in turn depend on the magnetic flux density and the temperature. Based on a parametric study, an inverse Jiles-Atherton hysteresis model is used and implemented for the magnetic field simulation. The temperature rise of the MR fluid in the annular gap caused by core loss (i.e. eddy current loss and hysteresis loss) and fluid motion is computed to investigate the current-force behavior. A group of impulsive tests was performed for the manufactured MR absorber with step exciting currents. The numerical and experimental results showed good agreement, which validates the effectiveness of the proposed multi-physics FEA model.
International Nuclear Information System (INIS)
Chang, S.M.; Kim, H.T.
2013-01-01
CANDU, a prototype of heavy water reactor is modeled for the moderator system with porous media buoyancy-effect heat-transfer turbulence model. OpenFOAM, a set of C++ classes and libraries developed under the object-oriented concept, is selected as the tool of numerical analysis. The result from this computational code is compared with experiments and other commercial code data through ANSYS-CFX and COMSOL Multi-physics. The three-dimensional code concerning buoyancy force, turbulence, and heat transfer is tested and shown to be successful for the analysis of thermo-hydraulic system of heavy water reactors. (authors)
Validation uncertainty of MATRA code for subchannel void distributions
Energy Technology Data Exchange (ETDEWEB)
Hwang, Dae-Hyun; Kim, S. J.; Kwon, H.; Seo, K. W. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2014-10-15
To extend code capability to the whole core subchannel analysis, pre-conditioned Krylov matrix solvers such as BiCGSTAB and GMRES are implemented in MATRA code as well as parallel computing algorithms using MPI and OPENMP. It is coded by fortran 90, and has some user friendly features such as graphic user interface. MATRA code was approved by Korean regulation body for design calculation of integral-type PWR named SMART. The major role subchannel code is to evaluate core thermal margin through the hot channel analysis and uncertainty evaluation for CHF predictions. In addition, it is potentially used for the best estimation of core thermal hydraulic field by incorporating into multiphysics and/or multi-scale code systems. In this study we examined a validation process for the subchannel code MATRA specifically in the prediction of subchannel void distributions. The primary objective of validation is to estimate a range within which the simulation modeling error lies. The experimental data for subchannel void distributions at steady state and transient conditions was provided on the framework of OECD/NEA UAM benchmark program. The validation uncertainty of MATRA code was evaluated for a specific experimental condition by comparing the simulation result and experimental data. A validation process should be preceded by code and solution verification. However, quantification of verification uncertainty was not addressed in this study. The validation uncertainty of the MATRA code for predicting subchannel void distribution was evaluated for a single data point of void fraction measurement at a 5x5 PWR test bundle on the framework of OECD UAM benchmark program. The validation standard uncertainties were evaluated as 4.2%, 3.9%, and 2.8% with the Monte-Carlo approach at the axial levels of 2216 mm, 2669 mm, and 3177 mm, respectively. The sensitivity coefficient approach revealed similar results of uncertainties but did not account for the nonlinear effects on the
BEAVRS full core burnup calculation in hot full power condition by RMC code
International Nuclear Information System (INIS)
Liu, Shichang; Liang, Jingang; Wu, Qu; Guo, JuanJuan; Huang, Shanfang; Tang, Xiao; Li, Zeguang; Wang, Kan
2017-01-01
Highlights: • TMS and thermal scattering interpolation were developed to treat cross sections OTF. • Hybrid coupling system was developed for HFP burnup calculation of BEAVRS benchmark. • Domain decomposition was applied to handle memory problem of full core burnup. • Critical boron concentration with burnup by RMC agrees with the benchmark results. • RMC is capable of multi-physics coupling for simulations of nuclear reactors in HFP. - Abstract: Monte Carlo method can provide high fidelity neutronics analysis of different types of nuclear reactors, owing to its advantages of the flexible geometry modeling and the use of continuous-energy nuclear cross sections. However, nuclear reactors are complex systems with multi-physics interacting and coupling. MC codes can couple with depletion solver and thermal-hydraulics (T/H) codes simultaneously for the “transport-burnup-thermal-hydraulics” coupling calculations. MIT BEAVRS is a typical “transport-burnup-thermal-hydraulics” coupling benchmark. In this paper, RMC was coupled with sub-channel code COBRA, equipped with on-the-fly temperature-dependent cross section treatment and large-scale detailed burnup calculation based on domain decomposition. Then RMC was applied to the full core burnup calculations of BEAVRS benchmark in hot full power (HFP) condition. The numerical tests show that domain decomposition method can achieve the consistent results compared with original version of RMC while enlarging the computational burnup regions. The results of HFP by RMC agree well with the reference values of BEAVRS benchmark and also agree well with those of MC21. This work proves the feasibility and accuracy of RMC in multi-physics coupling and lifecycle simulations of nuclear reactors.
Multi-physics design and analyses of long life reactors for lunar outposts
Schriener, Timothy M.
event of a launch abort accident. Increasing the amount of fuel in the reactor core, and hence its operational life, would be possible by launching the reactor unfueled and fueling it on the Moon. Such a reactor would, thus, not be subject to launch criticality safety requirements. However, loading the reactor with fuel on the Moon presents a challenge, requiring special designs of the core and the fuel elements, which lend themselves to fueling on the lunar surface. This research investigates examples of both a solid core reactor that would be fueled at launch as well as an advanced concept which could be fueled on the Moon. Increasing the operational life of a reactor fueled at launch is exercised for the NaK-78 cooled Sectored Compact Reactor (SCoRe). A multi-physics design and analyses methodology is developed which iteratively couples together detailed Monte Carlo neutronics simulations with 3-D Computational Fluid Dynamics (CFD) and thermal-hydraulics analyses. Using this methodology the operational life of this compact, fast spectrum reactor is increased by reconfiguring the core geometry to reduce neutron leakage and parasitic absorption, for the same amount of HEU in the core, and meeting launch safety requirements. The multi-physics analyses determine the impacts of the various design changes on the reactor's neutronics and thermal-hydraulics performance. The option of increasing the operational life of a reactor by loading it on the Moon is exercised for the Pellet Bed Reactor (PeBR). The PeBR uses spherical fuel pellets and is cooled by He-Xe gas, allowing the reactor core to be loaded with fuel pellets and charged with working fluid on the lunar surface. The performed neutronics analyses ensure the PeBR design achieves a long operational life, and develops safe launch canister designs to transport the spherical fuel pellets to the lunar surface. The research also investigates loading the PeBR core with fuel pellets on the Moon using a transient Discrete
Energy Technology Data Exchange (ETDEWEB)
Weaver, Robert P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Miller, Paul [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Howley, Kirsten [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ferguson, Jim Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gisler, Galen Ross [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Plesko, Catherine Suzanne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Managan, Rob [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Owen, Mike [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wasem, Joseph [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bruck-Syal, Megan [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2016-01-15
The NNSA Laboratories have entered into an interagency collaboration with the National Aeronautics and Space Administration (NASA) to explore strategies for prevention of Earth impacts by asteroids. Assessment of such strategies relies upon use of sophisticated multi-physics simulation codes. This document describes the task of verifying and cross-validating, between Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL), modeling capabilities and methods to be employed as part of the NNSA-NASA collaboration. The approach has been to develop a set of test problems and then to compare and contrast results obtained by use of a suite of codes, including MCNP, RAGE, Mercury, Ares, and Spheral. This document provides a short description of the codes, an overview of the idealized test problems, and discussion of the results for deflection by kinetic impactors and stand-off nuclear explosions.
Perspectives on the development of next generation reactor systems safety analysis codes
International Nuclear Information System (INIS)
Zhang, H.
2015-01-01
'Full text:' Existing reactor system analysis codes, such as RELAP5-3D and TRAC, have gained worldwide success in supporting reactor safety analyses, as well as design and licensing of new reactors. These codes are important assets to the nuclear engineering research community, as well as to the nuclear industry. However, most of these codes were originally developed during the 1970s', and it becomes necessary to develop next-generation reactor system analysis codes for several reasons. Firstly, as new reactor designs emerge, there are new challenges emerging in numerical simulations of reactor systems such as long lasting transients and multi-physics phenomena. These new requirements are beyond the range of applicability of the existing system analysis codes. Advanced modeling and numerical methods must be taken into consideration to improve the existing capabilities. Secondly, by developing next-generation reactor system analysis codes, the knowledge (know how) in two phase flow modeling and the highly complex constitutive models will be transferred to the young generation of nuclear engineers. And thirdly, all computer codes have limited shelf life. It becomes less and less cost-effective to maintain a legacy code, due to the fast change of computer hardware and software environment. There are several critical perspectives in terms of developing next-generation reactor system analysis codes: 1) The success of the next-generation codes must be built upon the success of the existing codes. The knowledge of the existing codes, not just simply the manuals and codes, but knowing why and how, must be transferred to the next-generation codes. The next-generation codes should encompass the capability of the existing codes. The shortcomings of existing codes should be identified, understood, and properly categorized, for example into model deficiencies or numerical method deficiencies. 2) State-of-the-art models and numerical methods must be considered to
Perspectives on the development of next generation reactor systems safety analysis codes
Energy Technology Data Exchange (ETDEWEB)
Zhang, H., E-mail: Hongbin.Zhang@inl.gov [Idaho National Laboratory, Idaho Falls, ID (United States)
2015-07-01
'Full text:' Existing reactor system analysis codes, such as RELAP5-3D and TRAC, have gained worldwide success in supporting reactor safety analyses, as well as design and licensing of new reactors. These codes are important assets to the nuclear engineering research community, as well as to the nuclear industry. However, most of these codes were originally developed during the 1970s', and it becomes necessary to develop next-generation reactor system analysis codes for several reasons. Firstly, as new reactor designs emerge, there are new challenges emerging in numerical simulations of reactor systems such as long lasting transients and multi-physics phenomena. These new requirements are beyond the range of applicability of the existing system analysis codes. Advanced modeling and numerical methods must be taken into consideration to improve the existing capabilities. Secondly, by developing next-generation reactor system analysis codes, the knowledge (know how) in two phase flow modeling and the highly complex constitutive models will be transferred to the young generation of nuclear engineers. And thirdly, all computer codes have limited shelf life. It becomes less and less cost-effective to maintain a legacy code, due to the fast change of computer hardware and software environment. There are several critical perspectives in terms of developing next-generation reactor system analysis codes: 1) The success of the next-generation codes must be built upon the success of the existing codes. The knowledge of the existing codes, not just simply the manuals and codes, but knowing why and how, must be transferred to the next-generation codes. The next-generation codes should encompass the capability of the existing codes. The shortcomings of existing codes should be identified, understood, and properly categorized, for example into model deficiencies or numerical method deficiencies. 2) State-of-the-art models and numerical methods must be considered to
From concatenated codes to graph codes
DEFF Research Database (Denmark)
Justesen, Jørn; Høholdt, Tom
2004-01-01
We consider codes based on simple bipartite expander graphs. These codes may be seen as the first step leading from product type concatenated codes to more complex graph codes. We emphasize constructions of specific codes of realistic lengths, and study the details of decoding by message passing...
Alhilaly, Mohammad J.; Bootharaju, Megalamane Siddaramappa; Joshi, Chakra Prasad; Besong, Tabot M.D.; Emwas, Abdul-Hamid M.; Juarez-Mosqueda, Rosalba; Kaappa, Sami; Malola, Sami; Adil, Karim; Shkurenko, Aleksander; Hakkinen, Hannu; Eddaoudi, Mohamed; Bakr, Osman
2016-01-01
Engineering the surface ligands of metal nanoparticles is critical in designing unique arrangements of metal atoms. Here, we report the synthesis and total structure determination of a large box-shaped Ag-67 nanocluster (NC) protected by a mixed shell of thiolate (2,4-dimethylbenzenethiolate, SPhMe2) and phosphine (triphenylphosphine, PPh3) ligands. Single crystal X-ray diffraction (SCXRD) and electrospray ionization mass spectrometry (ESI-MS) revealed the cluster formula to be [Ag-67(SPhMe2)(32)(PPh3)(8)](3+). The crystal structure shows an Ag-23 metal core covered by a layer of Ag44S32P8 arranged in the shape of a box. The Ag-13, core was formed through an unprecedented centered cuboctahedron, i.e., Ag-13, unlike the common centered Ag-13 icosahedron geometry. Two types of ligand motifs, eight AgS3P and eight bridging thiols, were found to stabilize the whole cluster. The optical spectrum of this NC displayed highly structured multiple absorption peaks. The electronic structure and optical spectrum of Ag-67 were computed using time-dependent density functional theory (TDDFT) for both the full cluster [Ag-67(SPhMe2)(32)(PPh3)(8)](3+) and a reduced model [Ag-67(SH)(32)(PH3)(8)](3+). The lowest metal-to-metal transitions in the range 500-800 nm could be explained by considering the reduced model that shows almost identical electronic states to 32 free electrons in a jellium box. The successful synthesis of the large box-shaped Ag-67 NC facilitated by the combined use of phosphine and thiol paves the way for synthesizing other metal clusters with unprecedented shapes by judicious choice of thiols and phosphines.
International Nuclear Information System (INIS)
Campbell, G.C.; Canich, J.A.M; Cotton, F.A.; Duraj, S.A.; Haw, J.F.
1986-01-01
The tantalum complex (SMe 2 )Cl 2 Ta(μ-Cl) 2 (μ-SMe 2 )TaCl 2 (SMe 2 ), possessing a sigma 2 π 2 Ta=Ta double bond, reacts readily with PhSSPh to give (SMe 2 )Cl 3 Ta(μ-SPh) 2 TaCl 2 (SMe 2 ). In this reaction, the starting material loses the bridging SMe 2 ligand and two chloride bridges are broken while only two new SPh bridges are formed in the final product. This oxidative-addition reaction of the S-S single bond to the Ta=Ta double bond converts the face-sharing bioctahedron structure of the starting compound to an edge-sharing bioctahedron structure in the final dimer, with concomitant change of the oxidation state of tantalum from III to IV. The product is the first example of a d 1 -d 1 ditantalum thiolate-bridged dimer. Important structural data for (SMe 2 )Cl 3 Ta(μ-SPh) 2 TaCl 3 (SMe 2 ), which has an inversion center, are determined. The new compound crystallizes in the monoclinic space group C2/c with a = 17.934 (5) A, b = 12.445 (4) A, c = 11.705 (4) A, β = 92.50 (3) 0 , V = 2610 (2) A 3 , and Z = 4. Solid-state 13 C NMR spectroscopy with cross polarization and magic-angle spinning (CP/MAS) at 28 and -103 0 C provides evidence that this compound is diamagnetic. 12 references, 3 figures, 4 tables
Alhilaly, Mohammad J.
2016-10-13
Engineering the surface ligands of metal nanoparticles is critical in designing unique arrangements of metal atoms. Here, we report the synthesis and total structure determination of a large box-shaped Ag-67 nanocluster (NC) protected by a mixed shell of thiolate (2,4-dimethylbenzenethiolate, SPhMe2) and phosphine (triphenylphosphine, PPh3) ligands. Single crystal X-ray diffraction (SCXRD) and electrospray ionization mass spectrometry (ESI-MS) revealed the cluster formula to be [Ag-67(SPhMe2)(32)(PPh3)(8)](3+). The crystal structure shows an Ag-23 metal core covered by a layer of Ag44S32P8 arranged in the shape of a box. The Ag-13, core was formed through an unprecedented centered cuboctahedron, i.e., Ag-13, unlike the common centered Ag-13 icosahedron geometry. Two types of ligand motifs, eight AgS3P and eight bridging thiols, were found to stabilize the whole cluster. The optical spectrum of this NC displayed highly structured multiple absorption peaks. The electronic structure and optical spectrum of Ag-67 were computed using time-dependent density functional theory (TDDFT) for both the full cluster [Ag-67(SPhMe2)(32)(PPh3)(8)](3+) and a reduced model [Ag-67(SH)(32)(PH3)(8)](3+). The lowest metal-to-metal transitions in the range 500-800 nm could be explained by considering the reduced model that shows almost identical electronic states to 32 free electrons in a jellium box. The successful synthesis of the large box-shaped Ag-67 NC facilitated by the combined use of phosphine and thiol paves the way for synthesizing other metal clusters with unprecedented shapes by judicious choice of thiols and phosphines.
Multi-physics and multi-scale characterization of shale anisotropy
Sarout, J.; Nadri, D.; Delle Piane, C.; Esteban, L.; Dewhurst, D.; Clennell, M. B.
2012-12-01
Shales are the most abundant sedimentary rock type in the Earth's shallow crust. In the past decade or so, they have attracted increased attention from the petroleum industry as reservoirs, as well as more traditionally for their sealing capacity for hydrocarbon/CO2 traps or underground waste repositories. The effectiveness of both fundamental and applied shale research is currently limited by (i) the extreme variability of physical, mechanical and chemical properties observed for these rocks, and by (ii) the scarce data currently available. The variability in observed properties is poorly understood due to many factors that are often irrelevant for other sedimentary rocks. The relationships between these properties and the petrophysical measurements performed at the field and laboratory scales are not straightforward, translating to a scale dependency typical of shale behaviour. In addition, the complex and often anisotropic micro-/meso-structures of shales give rise to a directional dependency of some of the measured physical properties that are tensorial by nature such as permeability or elastic stiffness. Currently, fundamental understanding of the parameters controlling the directional and scale dependency of shale properties is far from complete. Selected results of a multi-physics laboratory investigation of the directional and scale dependency of some critical shale properties are reported. In particular, anisotropic features of shale micro-/meso-structures are related to the directional-dependency of elastic and fluid transport properties: - Micro-/meso-structure (μm to cm scale) characterization by electron microscopy and X-ray tomography; - Estimation of elastic anisotropy parameters on a single specimen using elastic wave propagation (cm scale); - Estimation of the permeability tensor using the steady-state method on orthogonal specimens (cm scale); - Estimation of the low-frequency diffusivity tensor using NMR method on orthogonal specimens (example
Assessment of MARMOT. A Mesoscale Fuel Performance Code
Energy Technology Data Exchange (ETDEWEB)
Tonks, M. R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Schwen, D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Y. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Chakraborty, P. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bai, X. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fromm, B. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Yu, J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Teague, M. C. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Andersson, D. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2015-04-01
MARMOT is the mesoscale fuel performance code under development as part of the US DOE Nuclear Energy Advanced Modeling and Simulation Program. In this report, we provide a high level summary of MARMOT, its capabilities, and its current state of validation. The purpose of MARMOT is to predict the coevolution of microstructure and material properties of nuclear fuel and cladding. It accomplished this using the phase field method coupled to solid mechanics and heat conduction. MARMOT is based on the Multiphysics Object-Oriented Simulation Environment (MOOSE), and much of its basic capability in the areas of the phase field method, mechanics, and heat conduction come directly from MOOSE modules. However, additional capability specific to fuel and cladding is available in MARMOT. While some validation of MARMOT has been completed in the areas of fission gas behavior and grain growth, much more validation needs to be conducted. However, new mesoscale data needs to be obtained in order to complete this validation.
Suturina, Elizaveta A; Nehrkorn, Joscha; Zadrozny, Joseph M; Liu, Junjie; Atanasov, Mihail; Weyhermüller, Thomas; Maganas, Dimitrios; Hill, Stephen; Schnegg, Alexander; Bill, Eckhard; Long, Jeffrey R; Neese, Frank
2017-03-06
The magnetic properties of pseudotetrahedral Co(II) complexes spawned intense interest after (PPh 4 ) 2 [Co(SPh) 4 ] was shown to be the first mononuclear transition-metal complex displaying slow relaxation of the magnetization in the absence of a direct current magnetic field. However, there are differing reports on its fundamental magnetic spin Hamiltonian (SH) parameters, which arise from inherent experimental challenges in detecting large zero-field splittings. There are also remarkable changes in the SH parameters of [Co(SPh) 4 ] 2- upon structural variations, depending on the counterion and crystallization conditions. In this work, four complementary experimental techniques are utilized to unambiguously determine the SH parameters for two different salts of [Co(SPh) 4 ] 2- : (PPh 4 ) 2 [Co(SPh) 4 ] (1) and (NEt 4 ) 2 [Co(SPh) 4 ] (2). The characterization methods employed include multifield SQUID magnetometry, high-field/high-frequency electron paramagnetic resonance (HF-EPR), variable-field variable-temperature magnetic circular dichroism (VTVH-MCD), and frequency domain Fourier transform THz-EPR (FD-FT THz-EPR). Notably, the paramagnetic Co(II) complex [Co(SPh) 4 ] 2- shows strong axial magnetic anisotropy in 1, with D = -55(1) cm -1 and E/D = 0.00(3), but rhombic anisotropy is seen for 2, with D = +11(1) cm -1 and E/D = 0.18(3). Multireference ab initio CASSCF/NEVPT2 calculations enable interpretation of the remarkable variation of D and its dependence on the electronic structure and geometry.
Singha, Kamini; Loheide, Steven P., II
2011-01-01
Visualising subsurface processes in hydrogeology and building intuition for how these processes are controlled by changes in forcing is hard for many undergraduate students. While numerical modelling is one way to help undergraduate students explore outcomes of multiple scenarios, many codes are not user-friendly with respect to defining domains,…
DEFF Research Database (Denmark)
Lepech, M.; Michel, Alexander; Geiker, Mette
2016-01-01
and widespread depassivation, are the mechanism behind experimental results of HPFRCC steel corrosion studies found in the literature. Such results provide an indication of the fundamental mechanisms by which steel reinforced HPFRCC materials may be more durable than traditional reinforced concrete and other......Using a newly developed multi-physics transport, corrosion, and cracking model, which models these phenomena as a coupled physiochemical processes, the role of HPFRCC crack control and formation in regulating steel reinforcement corrosion is investigated. This model describes transport of water...... and chemical species, the electric potential distribution in the HPFRCC, the electrochemical propagation of steel corrosion, and the role of microcracks in the HPFRCC material. Numerical results show that the reduction in anode and cathode size on the reinforcing steel surface, due to multiple crack formation...
Pawar, Sumedh; Sharma, Atul
2018-01-01
This work presents mathematical model and solution methodology for a multiphysics engineering problem on arc formation during welding and inside a nozzle. A general-purpose commercial CFD solver ANSYS FLUENT 13.0.0 is used in this work. Arc formation involves strongly coupled gas dynamics and electro-dynamics, simulated by solution of coupled Navier-Stoke equations, Maxwell's equations and radiation heat-transfer equation. Validation of the present numerical methodology is demonstrated with an excellent agreement with the published results. The developed mathematical model and the user defined functions (UDFs) are independent of the geometry and are applicable to any system that involves arc-formation, in 2D axisymmetric coordinates system. The high-pressure flow of SF6 gas in the nozzle-arc system resembles arc chamber of SF6 gas circuit breaker; thus, this methodology can be extended to simulate arcing phenomenon during current interruption.
Clark, Martyn; Samaniego, Luis; Freer, Jim
2014-05-01
Multi-model and multi-physics approaches are a popular tool in environmental modelling, with many studies focusing on optimally combining output from multiple model simulations to reduce predictive errors and better characterize predictive uncertainty. However, a careful and systematic analysis of different hydrological models reveals that individual models are simply small permutations of a master modeling template, and inter-model differences are overwhelmed by uncertainty in the choice of the parameter values in the model equations. Furthermore, inter-model differences do not explicitly represent the uncertainty in modeling a given process, leading to many situations where different models provide the wrong results for the same reasons. In other cases, the available morphological data does not support the very fine spatial discretization of the landscape that typifies many modern applications of process-based models. To make the uncertainty characterization problem worse, the uncertain parameter values in process-based models are often fixed (hard-coded), and the models lack the agility necessary to represent the tremendous heterogeneity in natural systems. This presentation summarizes results from a systematic analysis of uncertainty in process-based hydrological models, where we explicitly analyze the myriad of subjective decisions made throughout both the model development and parameter estimation process. Results show that much of the uncertainty is aleatory in nature - given a "complete" representation of dominant hydrologic processes, uncertainty in process parameterizations can be represented using an ensemble of model parameters. Epistemic uncertainty associated with process interactions and scaling behavior is still important, and these uncertainties can be represented using an ensemble of different spatial configurations. Finally, uncertainty in forcing data can be represented using ensemble methods for spatial meteorological analysis. Our systematic
International Nuclear Information System (INIS)
García-Salaberri, Pablo A.; Vera, Marcos
2016-01-01
A multiphysics model for liquid-feed Direct Methanol Fuel Cells is presented. The model accounts for two-dimensional (2D) across-the-channel anisotropic mass and charge transport in the anode and cathode Gas Diffusion Layers (GDLs), including the effect of GDL assembly compression and electrical contact resistances at the Bipolar Plate (BPP) and membrane interfaces. A one-dimensional (1D) across-the-membrane model is used to describe local species diffusion through the microporous layers, methanol/water crossover, proton transport, and electrochemical reactions, thereby coupling both GDL sub-models. The 2D/1D model is extended to the third dimension and supplemented with 1D descriptions of the flow channels to yield a 3D/1D + 1D model that is successfully validated. A parametric study is then conducted on the 2D/1D model to examine the effect of operating conditions on cell performance. The results show that an optimum methanol concentration exists that maximizes power output due to the trade-off between anode polarization and cathode mixed overpotential. For fixed methanol concentration, cell performance is largely affected by the oxygen supply rate, cell temperature, and liquid/gas saturation levels. There is also an optimal GDL compression due to the trade-off between ohmic and concentration losses, which strongly depends on BPP material and, more weakly, on the actual operating conditions. - Highlights: • A multiphysics model for liquid-feed DMFCs is presented. • GDL anisotropic transport, assembly compression, and ohmic contact resistances are considered. • The model is successfully validated against previous experimental data. • Optimum methanol concentrations, GDL compressions, and operating temperatures are reported. • Oxygen-starved conditions with spontaneous hydrogen evolution in the anode are also considered.
International Nuclear Information System (INIS)
Romeo Velonà, A. D.; Gavignaud, I.; Meza, A.; Sommer-Larsen, J.; Napolitano, N. R.; Antonuccio-Delogu, V.; Cielo, S.
2013-01-01
We present results from SPH-cosmological simulations, including self-consistent modeling of supernova feedback and chemical evolution, of galaxies belonging to two clusters and 12 groups. We reproduce the mass-metallicity (ZM) relation of galaxies classified in two samples according to their star-forming (SF) activity, as parameterized by their specific star formation rate (sSFR), across a redshift range up to z = 2. The overall ZM relation for the composite population evolves according to a redshift-dependent quadratic functional form that is consistent with other empirical estimates, provided that the highest mass bin of the brightest central galaxies is excluded. Its slope shows irrelevant evolution in the passive sample, being steeper in groups than in clusters. However, the subsample of high-mass passive galaxies only is characterized by a steep increase of the slope with redshift, from which it can be inferred that the bulk of the slope evolution of the ZM relation is driven by the more massive passive objects. The scatter of the passive sample is dominated by low-mass galaxies at all redshifts and keeps constant over cosmic times. The mean metallicity is highest in cluster cores and lowest in normal groups, following the same environmental sequence as that previously found in the red sequence building. The ZM relation for the SF sample reveals an increasing scatter with redshift, indicating that it is still being built at early epochs. The SF galaxies make up a tight sequence in the SFR-M * plane at high redshift, whose scatter increases with time alongside the consolidation of the passive sequence. We also confirm the anti-correlation between sSFR and stellar mass, pointing at a key role of the former in determining the galaxy downsizing, as the most significant means of diagnostics of the star formation efficiency. Likewise, an anti-correlation between sSFR and metallicity can be established for the SF galaxies, while on the contrary more active galaxies
Xenakis, A M; Lind, S J; Stansby, P K; Rogers, B D
2017-03-01
Tsunamis caused by landslides may result in significant destruction of the surroundings with both societal and industrial impact. The 1958 Lituya Bay landslide and tsunami is a recent and well-documented terrestrial landslide generating a tsunami with a run-up of 524 m. Although recent computational techniques have shown good performance in the estimation of the run-up height, they fail to capture all the physical processes, in particular, the landslide-entry profile and interaction with the water. Smoothed particle hydrodynamics (SPH) is a versatile numerical technique for describing free-surface and multi-phase flows, particularly those that exhibit highly nonlinear deformation in landslide-generated tsunamis. In the current work, the novel multi-phase incompressible SPH method with shifting is applied to the Lituya Bay tsunami and landslide and is the first methodology able to reproduce realistically both the run-up and landslide-entry as documented in a benchmark experiment. The method is the first paper to develop a realistic implementation of the physics that in addition to the non-Newtonian rheology of the landslide includes turbulence in the water phase and soil saturation. Sensitivity to the experimental initial conditions is also considered. This work demonstrates the ability of the proposed method in modelling challenging environmental multi-phase, non-Newtonian and turbulent flows.
Clementel, N.; Madura, T. I.; Kruip, C. J. H.; Icke, V.; Gull, T. R.
2014-01-01
Eta Carinae is an ideal astrophysical laboratory for studying massive binary interactions and evolution, and stellar wind-wind collisions. Recent three-dimensional (3D) simulations set the stage for understanding the highly complex 3D flows in Eta Car. Observations of different broad high- and low-ionization forbidden emission lines provide an excellent tool to constrain the orientation of the system, the primary's mass-loss rate, and the ionizing flux of the hot secondary. In this work we present the first steps towards generating synthetic observations to compare with available and future HST/STIS data. We present initial results from full 3D radiative transfer simulations of the interacting winds in Eta Car. We use the SimpleX algorithm to post-process the output from 3D SPH simulations and obtain the ionization fractions of hydrogen and helium assuming three different mass-loss rates for the primary star. The resultant ionization maps of both species constrain the regions where the observed forbidden emission lines can form. Including collisional ionization is necessary to achieve a better description of the ionization states, especially in the areas shielded from the secondary's radiation. We find that reducing the primary's mass-loss rate increases the volume of ionized gas, creating larger areas where the forbidden emission lines can form. We conclude that post processing 3D SPH data with SimpleX is a viable tool to create ionization maps for Eta Car.
Automatic coding method of the ACR Code
International Nuclear Information System (INIS)
Park, Kwi Ae; Ihm, Jong Sool; Ahn, Woo Hyun; Baik, Seung Kook; Choi, Han Yong; Kim, Bong Gi
1993-01-01
The authors developed a computer program for automatic coding of ACR(American College of Radiology) code. The automatic coding of the ACR code is essential for computerization of the data in the department of radiology. This program was written in foxbase language and has been used for automatic coding of diagnosis in the Department of Radiology, Wallace Memorial Baptist since May 1992. The ACR dictionary files consisted of 11 files, one for the organ code and the others for the pathology code. The organ code was obtained by typing organ name or code number itself among the upper and lower level codes of the selected one that were simultaneous displayed on the screen. According to the first number of the selected organ code, the corresponding pathology code file was chosen automatically. By the similar fashion of organ code selection, the proper pathologic dode was obtained. An example of obtained ACR code is '131.3661'. This procedure was reproducible regardless of the number of fields of data. Because this program was written in 'User's Defined Function' from, decoding of the stored ACR code was achieved by this same program and incorporation of this program into program in to another data processing was possible. This program had merits of simple operation, accurate and detail coding, and easy adjustment for another program. Therefore, this program can be used for automation of routine work in the department of radiology
Hinds, Erold W. (Principal Investigator)
1996-01-01
This report describes the progress made towards the completion of a specific task on error-correcting coding. The proposed research consisted of investigating the use of modulation block codes as the inner code of a concatenated coding system in order to improve the overall space link communications performance. The study proposed to identify and analyze candidate codes that will complement the performance of the overall coding system which uses the interleaved RS (255,223) code as the outer code.
A Finite-Volume computational mechanics framework for multi-physics coupled fluid-stress problems
International Nuclear Information System (INIS)
Bailey, C; Cross, M.; Pericleous, K.
1998-01-01
Where there is a strong interaction between fluid flow, heat transfer and stress induced deformation, it may not be sufficient to solve each problem separately (i.e. fluid vs. stress, using different techniques or even different computer codes). This may be acceptable where the interaction is static, but less so, if it is dynamic. It is desirable for this reason to develop software that can accommodate both requirements (i.e. that of fluid flow and that of solid mechanics) in a seamless environment. This is accomplished in the University of Greenwich code PHYSICA, which solves both the fluid flow problem and the stress-strain equations in a unified Finite-Volume environment, using an unstructured computational mesh that can deform dynamically. Example applications are given of the work of the group in the metals casting process (where thermal stresses cause elasto- visco-plastic distortion)
Gagie, Travis
2005-01-01
We present a new algorithm for dynamic prefix-free coding, based on Shannon coding. We give a simple analysis and prove a better upper bound on the length of the encoding produced than the corresponding bound for dynamic Huffman coding. We show how our algorithm can be modified for efficient length-restricted coding, alphabetic coding and coding with unequal letter costs.
Fundamentals of convolutional coding
Johannesson, Rolf
2015-01-01
Fundamentals of Convolutional Coding, Second Edition, regarded as a bible of convolutional coding brings you a clear and comprehensive discussion of the basic principles of this field * Two new chapters on low-density parity-check (LDPC) convolutional codes and iterative coding * Viterbi, BCJR, BEAST, list, and sequential decoding of convolutional codes * Distance properties of convolutional codes * Includes a downloadable solutions manual
Directory of Open Access Journals (Sweden)
Atamewoue Surdive
2017-12-01
Full Text Available In this paper, we define linear codes and cyclic codes over a finite Krasner hyperfield and we characterize these codes by their generator matrices and parity check matrices. We also demonstrate that codes over finite Krasner hyperfields are more interesting for code theory than codes over classical finite fields.
Eichhöfer, Andreas; Lebedkin, Sergei
2018-01-16
Reactions of [Mn{N(SiMe 3 ) 2 } 2 ] 2 with 2.1 equiv of RSH, R = Ph or Mes = C 6 H 2 -2,4,6-(CH 3 ) 3 , yield compounds of the formal composition "Mn(SR) 2 ". Single-crystal X-ray diffraction reveals that ∞ 1 [Mn(SMes) 2 ] forms one-dimensional chains in the crystal via μ 2 -SMes bridges, whereas ∞ 3 [Mn 4 (SPh) 8 ] comprises a three-dimensional network in which adamantanoid cages composed of four Mn atoms and six μ 2 -bridging SPh ligands are connected in three dimensions by doubly bridging SPh ligands. Thermogravimetric analysis and powder diffractometry indicate an reversible uptake of solvent molecules (tetrahydrofuran) into the channels of ∞ 1 [Mn(SMes) 2 ]. Magnetic measurements reveal antiferromagnetic coupling for both compounds with J = -8.2 cm -1 ( ∞ 1 [Mn(SMes) 2 ]) and -10.0 cm -1 ( ∞ 3 [Mn 4 (SPh) 8 ]), respectively. Their optical absorption and photoluminescence (PL) excitation spectra display characteristic d-d bands of Mn 2+ ions in the visible spectral region. Both compounds emit bright phosphorescence at ∼800 nm at low temperatures (SMes) 2 ] retains a moderately intense emission at ambient temperature (with a quantum yield of 1.2%). Similar PL properties are also found for the related selenolate complexes ∞ 1 [Mn(SeR) 2 ] (R = Ph, Mes).
International Nuclear Information System (INIS)
Gomez Torres, Armando Miguel
2011-01-01
This doctoral thesis describes the methodological development of coupled neutron-kinetics/thermal-hydraulics codes for the design and safety analysis of reactor systems taking into account the feedback mechanisms on the fuel rod level, according to different approaches. A central part of this thesis is the development and validation of a high fidelity simulation tool, DYNSUB, which results from the ''two-way-coupling'' of DYN3D-SP3 and SUBCHANFLOW. It allows the determination of local safety parameters through a detailed description of the core behavior under stationary and transient conditions at fuel rod level.
Directory of Open Access Journals (Sweden)
Sulin Garro Acón
2012-11-01
Full Text Available En este estudio se analizó la transferencia de calor en tres disipadores de calor utilizados para enfriar los procesadores de computadoras de escritorio. El objetivo de estos disipadores es evitar el sobrecalentamiento de la unidad de procesamiento y la consecuente reducción de la vida útil del computador. Los disipadores de calor se modelaron usando COMSOL Multiphysics con las dimensiones reales de los dispositivos y la generación de calor se modeló con una fuente puntual. Luego se modificaron los diseños de los disipadores para lograr una temperatura más baja en la zona más caliente del procesador. El resultado fue una reducción en la temperatura en el rango de 5-78 grados Kelvin, al rediseñarse el disipador de calor con variaciones feasibles como la reducción del grosor de las placas de intercambio de calor y el aumento de su número. Esto demuestra la posibilidad de desarrollar diseños optimizados para disipadores de calor que no requieran más materiales sino una mejor ingeniería. El trabajo se inició como parte del curso CM-4101 Modelización y Simulación.In this study, the heat transfer of three desktop- computer heat sinks was analyzed. The objective of using these heat sinks is to avoid overheating of the computer’s processing unit and in turn reduce the corresponding loss in the unit’s service time. The heat sinks were modeled using COMSOL Multiphysics with the actual dimensions of the devices, and heat generation was modeled with a point source. In the next step, the heat sink designs were modified to achieve a lower temperature in the higher temperature location on the heat sink. The results were temperature reductions in the range of 5-78 degrees Kelvin, by making feasible variations in design such as reducing the thickness of the heat exchanger fins and increasing their number. This paper demonstrates that there is room to develop improved designs that do not require more materials but rather a better engineering
Vector Network Coding Algorithms
Ebrahimi, Javad; Fragouli, Christina
2010-01-01
We develop new algebraic algorithms for scalar and vector network coding. In vector network coding, the source multicasts information by transmitting vectors of length L, while intermediate nodes process and combine their incoming packets by multiplying them with L x L coding matrices that play a similar role as coding c in scalar coding. Our algorithms for scalar network jointly optimize the employed field size while selecting the coding coefficients. Similarly, for vector coding, our algori...
Energy Technology Data Exchange (ETDEWEB)
Anderson, Jonas T., E-mail: jonastyleranderson@gmail.com
2013-03-15
In this paper we define homological stabilizer codes on qubits which encompass codes such as Kitaev's toric code and the topological color codes. These codes are defined solely by the graphs they reside on. This feature allows us to use properties of topological graph theory to determine the graphs which are suitable as homological stabilizer codes. We then show that all toric codes are equivalent to homological stabilizer codes on 4-valent graphs. We show that the topological color codes and toric codes correspond to two distinct classes of graphs. We define the notion of label set equivalencies and show that under a small set of constraints the only homological stabilizer codes without local logical operators are equivalent to Kitaev's toric code or to the topological color codes. - Highlights: Black-Right-Pointing-Pointer We show that Kitaev's toric codes are equivalent to homological stabilizer codes on 4-valent graphs. Black-Right-Pointing-Pointer We show that toric codes and color codes correspond to homological stabilizer codes on distinct graphs. Black-Right-Pointing-Pointer We find and classify all 2D homological stabilizer codes. Black-Right-Pointing-Pointer We find optimal codes among the homological stabilizer codes.
Implementationof a modular software system for multiphysical processes in porous media
Naumov, Dmitri; Watanabe, Norihiro; Bilke, Lars; Fischer, Thomas; Lehmann, Christoph; Rink, Karsten; Walther, Marc; Wang, Wenqing; Kolditz, Olaf
2016-04-01
Subsurface georeservoirs are a candidate technology for large scale energy storage required as part of the transition to renewable energy sources. The increased use of the subsurface results in competing interests and possible impacts on protected entities. To optimize and plan the use of the subsurface in large scale scenario analyses,powerful numerical frameworks are required that aid process understanding and can capture the coupled thermal (T), hydraulic (H), mechanical (M), and chemical (C) processes with high computational efficiency. Due to having a multitude of different couplings between basic T, H, M, or C processes and the necessity to implement new numerical schemes the development focus has moved to software's modularity. The decreased coupling between the components results in two major advantages: easier addition of specialized processes and improvement of the code's testability and therefore its quality. The idea of modularization is implemented on several levels, in addition to library based separation of the previous code version, by using generalized algorithms available in the Standard Template Library and the Boost library, relying on efficient implementations of liner algebra solvers, using concepts when designing new types, and localization of frequently accessed data structures. This procedure shows certain benefits for a flexible high-performance framework applied to the analysis of multipurpose georeservoirs.
Diagnostic Coding for Epilepsy.
Williams, Korwyn; Nuwer, Marc R; Buchhalter, Jeffrey R
2016-02-01
Accurate coding is an important function of neurologic practice. This contribution to Continuum is part of an ongoing series that presents helpful coding information along with examples related to the issue topic. Tips for diagnosis coding, Evaluation and Management coding, procedure coding, or a combination are presented, depending on which is most applicable to the subject area of the issue.
Coding of Neuroinfectious Diseases.
Barkley, Gregory L
2015-12-01
Accurate coding is an important function of neurologic practice. This contribution to Continuum is part of an ongoing series that presents helpful coding information along with examples related to the issue topic. Tips for diagnosis coding, Evaluation and Management coding, procedure coding, or a combination are presented, depending on which is most applicable to the subject area of the issue.
International Nuclear Information System (INIS)
Ammar, Karim
2014-01-01
Since Phenix shutting down in 2010, CEA does not have Sodium Fast Reactor (SFR) in operating condition. According to global energetic challenge and fast reactor abilities, CEA launched a program of industrial demonstrator called ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration), a reactor with electric power capacity equal to 600 MW. Objective of the prototype is, in first to be a response to environmental constraints, in second demonstrates the industrial viability of SFR reactor. The goal is to have a safety level at least equal to 3. generation reactors. ASTRID design integrates Fukushima feedback; Waste reprocessing (with minor actinide transmutation) and it linked industry. Installation safety is the priority. In all cases, no radionuclide should be released into environment. To achieve this objective, it is imperative to predict the impact of uncertainty sources on reactor behaviour. In this context, this thesis aims to develop new optimization methods for SFR cores. The goal is to improve the robustness and reliability of reactors in response to existing uncertainties. We will use ASTRID core as reference to estimate interest of new methods and tools developed. The impact of multi-Physics uncertainties in the calculation of the core performance and the use of optimization methods introduce new problems: How to optimize 'complex' cores (i.e. associated with design spaces of high dimensions with more than 20 variable parameters), taking into account the uncertainties? What is uncertainties behaviour for optimization core compare to reference core? Taking into account uncertainties, optimization core are they still competitive? Optimizations improvements are higher than uncertainty margins? The thesis helps to develop and implement methods necessary to take into account uncertainties in the new generation of simulation tools. Statistical methods to ensure consistency of complex multi-Physics simulation results are also
Energy Technology Data Exchange (ETDEWEB)
Aldemir, Tunc [The Ohio State Univ., Columbus, OH (United States); Denning, Richard [The Ohio State Univ., Columbus, OH (United States); Catalyurek, Umit [The Ohio State Univ., Columbus, OH (United States); Unwin, Stephen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2015-01-23
Reduction in safety margin can be expected as passive structures and components undergo degradation with time. Limitations in the traditional probabilistic risk assessment (PRA) methodology constrain its value as an effective tool to address the impact of aging effects on risk and for quantifying the impact of aging management strategies in maintaining safety margins. A methodology has been developed to address multiple aging mechanisms involving large numbers of components (with possibly statistically dependent failures) within the PRA framework in a computationally feasible manner when the sequencing of events is conditioned on the physical conditions predicted in a simulation environment, such as the New Generation System Code (NGSC) concept. Both epistemic and aleatory uncertainties can be accounted for within the same phenomenological framework and maintenance can be accounted for in a coherent fashion. The framework accommodates the prospective impacts of various intervention strategies such as testing, maintenance, and refurbishment. The methodology is illustrated with several examples.
International Nuclear Information System (INIS)
Sbragio, Ricardo
1999-01-01
The determination of natural frequencies and displacement Power Spectrum Density (PSD) of fuel rods in a fluid using Computational Fluid Dynamics and Finite Element Methods is presented. The rods are modeled as slender beams subjected to small displacements in a fluid using three-dimensional mesh. The incompressible Navier-Stokes and linear momentum balance equations are solved simultaneously using Spectrum code. Two examples from literature are analyzed. The first consists in one rod in a fluid. The excitation is an impulse force at the rod central node. The second example is a two rod system in a fluid. In this case, the excitation force is random and is determined from a PSD. (author)
International Nuclear Information System (INIS)
Aldemir, Tunc; Denning, Richard; Catalyurek, Umit; Unwin, Stephen
2015-01-01
Reduction in safety margin can be expected as passive structures and components undergo degradation with time. Limitations in the traditional probabilistic risk assessment (PRA) methodology constrain its value as an effective tool to address the impact of aging effects on risk and for quantifying the impact of aging management strategies in maintaining safety margins. A methodology has been developed to address multiple aging mechanisms involving large numbers of components (with possibly statistically dependent failures) within the PRA framework in a computationally feasible manner when the sequencing of events is conditioned on the physical conditions predicted in a simulation environment, such as the New Generation System Code (NGSC) concept. Both epistemic and aleatory uncertainties can be accounted for within the same phenomenological framework and maintenance can be accounted for in a coherent fashion. The framework accommodates the prospective impacts of various intervention strategies such as testing, maintenance, and refurbishment. The methodology is illustrated with several examples.
Extreme scale multi-physics simulations of the tsunamigenic 2004 Sumatra megathrust earthquake
Ulrich, T.; Gabriel, A. A.; Madden, E. H.; Wollherr, S.; Uphoff, C.; Rettenberger, S.; Bader, M.
2017-12-01
SeisSol (www.seissol.org) is an open-source software package based on an arbitrary high-order derivative Discontinuous Galerkin method (ADER-DG). It solves spontaneous dynamic rupture propagation on pre-existing fault interfaces according to non-linear friction laws, coupled to seismic wave propagation with high-order accuracy in space and time (minimal dispersion errors). SeisSol exploits unstructured meshes to account for complex geometries, e.g. high resolution topography and bathymetry, 3D subsurface structure, and fault networks. We present the up-to-date largest (1500 km of faults) and longest (500 s) dynamic rupture simulation modeling the 2004 Sumatra-Andaman earthquake. We demonstrate the need for end-to-end-optimization and petascale performance of scientific software to realize realistic simulations on the extreme scales of subduction zone earthquakes: Considering the full complexity of subduction zone geometries leads inevitably to huge differences in element sizes. The main code improvements include a cache-aware wave propagation scheme and optimizations of the dynamic rupture kernels using code generation. In addition, a novel clustered local-time-stepping scheme for dynamic rupture has been established. Finally, asynchronous output has been implemented to overlap I/O and compute time. We resolve the frictional sliding process on the curved mega-thrust and a system of splay faults, as well as the seismic wave field and seafloor displacement with frequency content up to 2.2 Hz. We validate the scenario by geodetic, seismological and tsunami observations. The resulting rupture dynamics shed new light on the activation and importance of splay faults.
Reacción de ligandos azufrados con el complejo au2pt (ch2p(Sph24,cl2
Directory of Open Access Journals (Sweden)
Guillermo Garzón
2010-07-01
Full Text Available Se describe la reacción de intercambio del cloro en el complejo au2pt (ch2p(Sph24,cl2 por los ligandos SCH2Ph-,S2CN(CH2CH3,2- y SCN-. Los nuevos derivados azufrados se caracterizan por análisis químico, espectroscopia infrarroja, electrónica y resonancia magnética nuclear protónica. Los ligandos se coordinan por el azufre a los dos átomos sw oro metálico en forma simétrica. El análisis elemental concuerda con las estequiomctrías y estructuras propuestas.
Ebrahimi, Javad; Fragouli, Christina
2010-01-01
We develop new algebraic algorithms for scalar and vector network coding. In vector network coding, the source multicasts information by transmitting vectors of length L, while intermediate nodes process and combine their incoming packets by multiplying them with L X L coding matrices that play a similar role as coding coefficients in scalar coding. Our algorithms for scalar network jointly optimize the employed field size while selecting the coding coefficients. Similarly, for vector co...
Sze, Vivienne; Marpe, Detlev
2014-01-01
Context-Based Adaptive Binary Arithmetic Coding (CABAC) is a method of entropy coding first introduced in H.264/AVC and now used in the latest High Efficiency Video Coding (HEVC) standard. While it provides high coding efficiency, the data dependencies in H.264/AVC CABAC make it challenging to parallelize and thus limit its throughput. Accordingly, during the standardization of entropy coding for HEVC, both aspects of coding efficiency and throughput were considered. This chapter describes th...
Generalized concatenated quantum codes
International Nuclear Information System (INIS)
Grassl, Markus; Shor, Peter; Smith, Graeme; Smolin, John; Zeng Bei
2009-01-01
We discuss the concept of generalized concatenated quantum codes. This generalized concatenation method provides a systematical way for constructing good quantum codes, both stabilizer codes and nonadditive codes. Using this method, we construct families of single-error-correcting nonadditive quantum codes, in both binary and nonbinary cases, which not only outperform any stabilizer codes for finite block length but also asymptotically meet the quantum Hamming bound for large block length.
DEFF Research Database (Denmark)
Sørensen, Jesper Hemming; Koike-Akino, Toshiaki; Orlik, Philip
2012-01-01
This paper proposes a concept called rateless feedback coding. We redesign the existing LT and Raptor codes, by introducing new degree distributions for the case when a few feedback opportunities are available. We show that incorporating feedback to LT codes can significantly decrease both...... the coding overhead and the encoding/decoding complexity. Moreover, we show that, at the price of a slight increase in the coding overhead, linear complexity is achieved with Raptor feedback coding....
Ariane, Mostapha; Kassinos, Stavros; Velaga, Sitaram; Alexiadis, Alessio
2018-04-01
In this paper, the mass transfer coefficient (permeability) of boundary layers containing motile cilia is investigated by means of discrete multi-physics. The idea is to understand the main mechanisms of mass transport occurring in a ciliated-layer; one specific application being inhaled drugs in the respiratory epithelium. The effect of drug diffusivity, cilia beat frequency and cilia flexibility is studied. Our results show the existence of three mass transfer regimes. A low frequency regime, which we called shielding regime, where the presence of the cilia hinders mass transport; an intermediate frequency regime, which we have called diffusive regime, where diffusion is the controlling mechanism; and a high frequency regime, which we have called convective regime, where the degree of bending of the cilia seems to be the most important factor controlling mass transfer in the ciliated-layer. Since the flexibility of the cilia and the frequency of the beat changes with age and health conditions, the knowledge of these three regimes allows prediction of how mass transfer varies with these factors. Copyright © 2018 Elsevier Ltd. All rights reserved.
Multiphysics control of a two-fluid coaxial atomizer supported by electric-charge on the liquid jet
Machicoane, Nathanael; Osuna, Rodrigo; Aliseda, Alberto
2017-11-01
We present an experimental setup to investigate multiphysics control strategies on atomization of a laminar fluid stream by a coaxial turbulent jet. Spray control (i.e. driving the droplet size distribution and the spatio-temporal location of the droplets towards a desired objective) has many potential engineering applications, but requires a mechanistic understanding of the processes that control droplet formation and transport (primary and secondary instabilities, turbulent transport, hydrodynamic and electric forces on the droplets, ...). We characterize experimentally the break-up dynamics in a canonical coaxial atomizer, and the spray structure (droplet size, location, and velocity as a function of time) in a series of open loop conditions with harmonic forcing of the gas swirl ratio, liquid injection rate, the electric field strength at the nozzle and along the spray development region. The effect of these actuators are characterized for different gas Reynolds numbers ranging from 104-106. This open-loop characterization of the injector will be used to develop reduced order models for feedback control, as well as to validate assumptions underlying an adjoint-based computational control strategy. This work is part of a large-scale project funded by an ONR MURI to provide fundamental understanding of the mechanisms for feedback control of sprays.
Sun, S.; Kou, J.; Yu, B.
2011-01-01
The temporal discretization scheme is one important ingredient of efficient simulator for two-phase flow in the fractured porous media. The application of single-scale temporal scheme is restricted by the rapid changes of the pressure and saturation in the fractured system with capillarity. In this paper, we propose a multi-scale time splitting strategy to simulate multi-scale multi-physics processes of two-phase flow in fractured porous media. We use the multi-scale time schemes for both the pressure and saturation equations; that is, a large time-step size is employed for the matrix domain, along with a small time-step size being applied in the fractures. The total time interval is partitioned into four temporal levels: the first level is used for the pressure in the entire domain, the second level matching rapid changes of the pressure in the fractures, the third level treating the response gap between the pressure and the saturation, and the fourth level applied for the saturation in the fractures. This method can reduce the computational cost arisen from the implicit solution of the pressure equation. Numerical examples are provided to demonstrate the efficiency of the proposed method.
Energy Technology Data Exchange (ETDEWEB)
Jonkman, Jason; Annoni, Jennifer; Hayman, Greg; Jonkman, Bonnie; Purkayastha, Avi
2017-01-01
This paper presents the development of FAST.Farm, a new multiphysics tool applicable to engineering problems in research and industry involving wind farm performance and cost optimization that is needed to address the current underperformance, failures, and expenses plaguing the wind industry. Achieving wind cost-of-energy targets - which requires improvements in wind farm performance and reliability, together with reduced uncertainty and expenditures - has been eluded by the complicated nature of the wind farm design problem, especially the sophisticated interaction between atmospheric phenomena and wake dynamics and array effects. FAST.Farm aims to balance the need for accurate modeling of the relevant physics for predicting power performance and loads while maintaining low computational cost to support a highly iterative and probabilistic design process and system-wide optimization. FAST.Farm makes use of FAST to model the aero-hydro-servo-elastics of distinct turbines in the wind farm, and it is based on some of the principles of the Dynamic Wake Meandering (DWM) model, but avoids many of the limitations of existing DWM implementations.
Development of FAST.Farm: A New Multiphysics Engineering Tool for Wind-Farm Design and Analysis
Energy Technology Data Exchange (ETDEWEB)
Jonkman, Jason; Annoni, Jennifer; Hayman, Greg; Jonkman, Bonnie; Purkayastha, Avi
2017-01-09
This paper presents the development of FAST.Farm, a new multiphysics tool applicable to engineering problems in research and industry involving wind farm performance and cost optimization that is needed to address the current underperformance, failures, and expenses plaguing the wind industry. Achieving wind cost-of-energy targets - which requires improvements in wind farm performance and reliability, together with reduced uncertainty and expenditures - has been eluded by the complicated nature of the wind farm design problem, especially the sophisticated interaction between atmospheric phenomena and wake dynamics and array effects. FAST.Farm aims to balance the need for accurate modeling of the relevant physics for predicting power performance and loads while maintaining low computational cost to support a highly iterative and probabilistic design process and system-wide optimization. FAST.Farm makes use of FAST to model the aero-hydro-servo-elastics of distinct turbines in the wind farm, and it is based on some of the principles of the Dynamic Wake Meandering (DWM) model, but avoids many of the limitations of existing DWM implementations.
Gao, Wen
2015-01-01
This comprehensive and accessible text/reference presents an overview of the state of the art in video coding technology. Specifically, the book introduces the tools of the AVS2 standard, describing how AVS2 can help to achieve a significant improvement in coding efficiency for future video networks and applications by incorporating smarter coding tools such as scene video coding. Topics and features: introduces the basic concepts in video coding, and presents a short history of video coding technology and standards; reviews the coding framework, main coding tools, and syntax structure of AV
Abraham, Nikhil
2015-01-01
Hands-on exercises help you learn to code like a pro No coding experience is required for Coding For Dummies,your one-stop guide to building a foundation of knowledge inwriting computer code for web, application, and softwaredevelopment. It doesn't matter if you've dabbled in coding or neverwritten a line of code, this book guides you through the basics.Using foundational web development languages like HTML, CSS, andJavaScript, it explains in plain English how coding works and whyit's needed. Online exercises developed by Codecademy, a leading online codetraining site, help hone coding skill
Energy Technology Data Exchange (ETDEWEB)
S. R. Novascone; B. W. Spencer; D. Andrs; R. L. Williamson; J. D. Hales; D. M. Perez
2013-05-01
The behavior of nuclear fuel in the reactor environment is affected by multiple physics, most notably heat conduction and solid mechanics, which can have a strong influence on each other. To provide credible solutions, a fuel performance simulation code must have the ability to obtain solutions for each of the physics, including coupling between them. Solution strategies for solving systems of coupled equations can be categorized as loosely-coupled, where the individual physics are solved separately, keeping the solutions for the other physics fixed at each iteration, or tightly coupled, where the nonlinear solver simultaneously drives down the residual for each physics, taking into account the coupling between the physics in each nonlinear iteration. In this paper, we compare the performance of loosely and tightly coupled solution algorithms for thermomechanical problems involving coupled thermal and mechanical contact, which is a primary source of interdependence between thermal and mechanical solutions in fuel performance models. The results indicate that loosely-coupled simulations require significantly more nonlinear iterations, and may lead to convergence trouble when the thermal conductivity of the gap is too small. We also apply the tightly coupled solution strategy to a nuclear fuel simulation of an experiment in a test reactor. Studying the results from these simulations indicates that perhaps convergence for either approach may be problem dependent, i.e., there may be problems for which a loose coupled approach converges, where tightly coupled won’t converge and vice versa.
International Nuclear Information System (INIS)
Novascone, S. R.; Spencer, B. W.; Andrs, D.; Williamson, R. L.; Hales, J. D.; Perez, D. M.
2013-01-01
The behavior of nuclear fuel in the reactor environment is affected by multiple physics, most notably heat conduction and solid mechanics, which can have a strong influence on each other. To provide credible solutions, a fuel performance simulation code must have the ability to obtain solutions for each of the physics, including coupling between them. Solution strategies for solving systems of coupled equations can be categorized as loosely-coupled, where the individual physics are solved separately, keeping the solutions for the other physics fixed at each iteration, or tightly coupled, where the nonlinear solver simultaneously drives down the residual for each physics, taking into account the coupling between the physics in each nonlinear iteration. In this paper, we compare the performance of loosely and tightly coupled solution algorithms for thermomechanical problems involving coupled thermal and mechanical contact, which is a primary source of interdependence between thermal and mechanical solutions in fuel performance models. The results indicate that loosely-coupled simulations require significantly more nonlinear iterations, and may lead to convergence trouble when the thermal conductivity of the gap is too small. We also apply the tightly coupled solution strategy to a nuclear fuel simulation of an experiment in a test reactor. Studying the results from these simulations indicates that perhaps convergence for either approach may be problem dependent, i.e., there may be problems for which a loose coupled approach converges, where tightly coupled won't converge and vice versa. (authors)
Development of Adaptive Model Refinement (AMoR) for Multiphysics and Multifidelity Problems
Energy Technology Data Exchange (ETDEWEB)
Turinsky, Paul [North Carolina State Univ., Raleigh, NC (United States)
2015-02-09
This project investigated the development and utilization of Adaptive Model Refinement (AMoR) for nuclear systems simulation applications. AMoR refers to utilization of several models of physical phenomena which differ in prediction fidelity. If the highest fidelity model is judged to always provide or exceeded the desired fidelity, than if one can determine the difference in a Quantity of Interest (QoI) between the highest fidelity model and lower fidelity models, one could utilize the fidelity model that would just provide the magnitude of the QoI desired. Assuming lower fidelity models require less computational resources, in this manner computational efficiency can be realized provided the QoI value can be accurately and efficiently evaluated. This work utilized Generalized Perturbation Theory (GPT) to evaluate the QoI, by convoluting the GPT solution with the residual of the highest fidelity model determined using the solution from lower fidelity models. Specifically, a reactor core neutronics problem and thermal-hydraulics problem were studied to develop and utilize AMoR. The highest fidelity neutronics model was based upon the 3D space-time, two-group, nodal diffusion equations as solved in the NESTLE computer code. Added to the NESTLE code was the ability to determine the time-dependent GPT neutron flux. The lower fidelity neutronics model was based upon the point kinetics equations along with utilization of a prolongation operator to determine the 3D space-time, two-group flux. The highest fidelity thermal-hydraulics model was based upon the space-time equations governing fluid flow in a closed channel around a heat generating fuel rod. The Homogenous Equilibrium Mixture (HEM) model was used for the fluid and Finite Difference Method was applied to both the coolant and fuel pin energy conservation equations. The lower fidelity thermal-hydraulic model was based upon the same equations as used for the highest fidelity model but now with coarse spatial
Multi-objective and multi-physics optimization methodology for SFR core: application to CFV concept
International Nuclear Information System (INIS)
Fabbris, Olivier
2014-01-01
Nuclear reactor core design is a highly multidisciplinary task where neutronics, thermal-hydraulics, fuel thermo-mechanics and fuel cycle are involved. The problem is moreover multi-objective (several performances) and highly dimensional (several tens of design parameters).As the reference deterministic calculation codes for core characterization require important computing resources, the classical design method is not well suited to investigate and optimize new innovative core concepts. To cope with these difficulties, a new methodology has been developed in this thesis. Our work is based on the development and validation of simplified neutronics and thermal-hydraulics calculation schemes allowing the full characterization of Sodium-cooled Fast Reactor core regarding both neutronics performances and behavior during thermal hydraulic dimensioning transients.The developed methodology uses surrogate models (or meta-models) able to replace the neutronics and thermal-hydraulics calculation chain. Advanced mathematical methods for the design of experiment, building and validation of meta-models allows substituting this calculation chain by regression models with high prediction capabilities.The methodology is applied on a very large design space to a challenging core called CFV (French acronym for low void effect core) with a large gain on the sodium void effect. Global sensitivity analysis leads to identify the significant design parameters on the core design and its behavior during unprotected transient which can lead to severe accidents. Multi-objective optimizations lead to alternative core configurations with significantly improved performances. Validation results demonstrate the relevance of the methodology at the pre-design stage of a Sodium-cooled Fast Reactor core. (author) [fr
Discussion on LDPC Codes and Uplink Coding
Andrews, Ken; Divsalar, Dariush; Dolinar, Sam; Moision, Bruce; Hamkins, Jon; Pollara, Fabrizio
2007-01-01
This slide presentation reviews the progress that the workgroup on Low-Density Parity-Check (LDPC) for space link coding. The workgroup is tasked with developing and recommending new error correcting codes for near-Earth, Lunar, and deep space applications. Included in the presentation is a summary of the technical progress of the workgroup. Charts that show the LDPC decoder sensitivity to symbol scaling errors are reviewed, as well as a chart showing the performance of several frame synchronizer algorithms compared to that of some good codes and LDPC decoder tests at ESTL. Also reviewed is a study on Coding, Modulation, and Link Protocol (CMLP), and the recommended codes. A design for the Pseudo-Randomizer with LDPC Decoder and CRC is also reviewed. A chart that summarizes the three proposed coding systems is also presented.
Locally orderless registration code
DEFF Research Database (Denmark)
2012-01-01
This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows.......This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows....
Indian Academy of Sciences (India)
Shannon limit of the channel. Among the earliest discovered codes that approach the. Shannon limit were the low density parity check (LDPC) codes. The term low density arises from the property of the parity check matrix defining the code. We will now define this matrix and the role that it plays in decoding. 2. Linear Codes.
Manually operated coded switch
International Nuclear Information System (INIS)
Barnette, J.H.
1978-01-01
The disclosure related to a manually operated recodable coded switch in which a code may be inserted, tried and used to actuate a lever controlling an external device. After attempting a code, the switch's code wheels must be returned to their zero positions before another try is made
Jones, Lyell K; Ney, John P
2016-12-01
Accurate coding is critically important for clinical practice and research. Ongoing changes to diagnostic and billing codes require the clinician to stay abreast of coding updates. Payment for health care services, data sets for health services research, and reporting for medical quality improvement all require accurate administrative coding. This article provides an overview of administrative coding for patients with muscle disease and includes a case-based review of diagnostic and Evaluation and Management (E/M) coding principles in patients with myopathy. Procedural coding for electrodiagnostic studies and neuromuscular ultrasound is also reviewed.
Crompton, Helen; LaFrance, Jason; van 't Hooft, Mark
2012-01-01
A QR (quick-response) code is a two-dimensional scannable code, similar in function to a traditional bar code that one might find on a product at the supermarket. The main difference between the two is that, while a traditional bar code can hold a maximum of only 20 digits, a QR code can hold up to 7,089 characters, so it can contain much more…
International Nuclear Information System (INIS)
Nelson, Andrew F.; Wetzstein, M.; Naab, T.
2009-01-01
We continue our presentation of VINE. In this paper, we begin with a description of relevant architectural properties of the serial and shared memory parallel computers on which VINE is intended to run, and describe their influences on the design of the code itself. We continue with a detailed description of a number of optimizations made to the layout of the particle data in memory and to our implementation of a binary tree used to access that data for use in gravitational force calculations and searches for smoothed particle hydrodynamics (SPH) neighbor particles. We describe the modifications to the code necessary to obtain forces efficiently from special purpose 'GRAPE' hardware, the interfaces required to allow transparent substitution of those forces in the code instead of those obtained from the tree, and the modifications necessary to use both tree and GRAPE together as a fused GRAPE/tree combination. We conclude with an extensive series of performance tests, which demonstrate that the code can be run efficiently and without modification in serial on small workstations or in parallel using the OpenMP compiler directives on large-scale, shared memory parallel machines. We analyze the effects of the code optimizations and estimate that they improve its overall performance by more than an order of magnitude over that obtained by many other tree codes. Scaled parallel performance of the gravity and SPH calculations, together the most costly components of most simulations, is nearly linear up to at least 120 processors on moderate sized test problems using the Origin 3000 architecture, and to the maximum machine sizes available to us on several other architectures. At similar accuracy, performance of VINE, used in GRAPE-tree mode, is approximately a factor 2 slower than that of VINE, used in host-only mode. Further optimizations of the GRAPE/host communications could improve the speed by as much as a factor of 3, but have not yet been implemented in VINE
Directory of Open Access Journals (Sweden)
Yanjuan Wang
2017-10-01
Full Text Available Abstract: In this paper, the endothermic methanol decomposition reaction is used to obtain syngas by transforming middle and low temperature solar energy into chemical energy. A two-dimensional multiphysics coupling model of a middle and low temperature of 150~300 °C solar receiver/reactor was developed, which couples momentum equation in porous catalyst bed, the governing mass conservation with chemical reaction, and energy conservation incorporating conduction/convection/radiation heat transfer. The complex thermochemical conversion process of the middle and low temperature solar receiver/reactor (MLTSRR system was analyzed. The numerical finite element method (FEM model was validated by comparing it with the experimental data and a good agreement was obtained, revealing that the numerical FEM model is reliable. The characteristics of chemical reaction, coupled heat transfer, the components of reaction products, and the temperature fields in the receiver/reactor were also revealed and discussed. The effects of the annulus vacuum space and the glass tube on the performance of the solar receiver/reactor were further studied. It was revealed that when the direct normal irradiation increases from 200 W/m2 to 800 W/m2, the theoretical efficiency of solar energy transformed into chemical energy can reach 0.14–0.75. When the methanol feeding rate is 13 kg/h, the solar flux increases from 500 W/m2 to 1000 W/m2, methanol conversion can fall by 6.8–8.9% with air in the annulus, and methanol conversion can decrease by 21.8–28.9% when the glass is removed from the receiver/reactor.
Directory of Open Access Journals (Sweden)
Hyoung Tae Kim
2016-01-01
Full Text Available The moderator system of CANDU, a prototype of PHWR (pressurized heavy-water reactor, has been modeled in multidimension for the computation based on CFD (computational fluid dynamics technique. Three CFD codes are tested in modeled hydrothermal systems of heavy-water reactors. Commercial codes, COMSOL Multiphysics and ANSYS-CFX with OpenFOAM, an open-source code, are introduced for the various simplified and practical problems. All the implemented computational codes are tested for a benchmark problem of STERN laboratory experiment with a precise modeling of tubes, compared with each other as well as the measured data and a porous model based on the experimental correlation of pressure drop. Also the effect of turbulence model is discussed for these low Reynolds number flows. As a result, they are shown to be successful for the analysis of three-dimensional numerical models related to the calandria system of CANDU reactors.
Walker, Judy L
2000-01-01
When information is transmitted, errors are likely to occur. Coding theory examines efficient ways of packaging data so that these errors can be detected, or even corrected. The traditional tools of coding theory have come from combinatorics and group theory. Lately, however, coding theorists have added techniques from algebraic geometry to their toolboxes. In particular, by re-interpreting the Reed-Solomon codes, one can see how to define new codes based on divisors on algebraic curves. For instance, using modular curves over finite fields, Tsfasman, Vladut, and Zink showed that one can define a sequence of codes with asymptotically better parameters than any previously known codes. This monograph is based on a series of lectures the author gave as part of the IAS/PCMI program on arithmetic algebraic geometry. Here, the reader is introduced to the exciting field of algebraic geometric coding theory. Presenting the material in the same conversational tone of the lectures, the author covers linear codes, inclu...
AX-GADGET: a new code for cosmological simulations of Fuzzy Dark Matter and Axion models
Nori, Matteo; Baldi, Marco
2018-05-01
We present a new module of the parallel N-Body code P-GADGET3 for cosmological simulations of light bosonic non-thermal dark matter, often referred as Fuzzy Dark Matter (FDM). The dynamics of the FDM features a highly non-linear Quantum Potential (QP) that suppresses the growth of structures at small scales. Most of the previous attempts of FDM simulations either evolved suppressed initial conditions, completely neglecting the dynamical effects of QP throughout cosmic evolution, or resorted to numerically challenging full-wave solvers. The code provides an interesting alternative, following the FDM evolution without impairing the overall performance. This is done by computing the QP acceleration through the Smoothed Particle Hydrodynamics (SPH) routines, with improved schemes to ensure precise and stable derivatives. As an extension of the P-GADGET3 code, it inherits all the additional physics modules implemented up to date, opening a wide range of possibilities to constrain FDM models and explore its degeneracies with other physical phenomena. Simulations are compared with analytical predictions and results of other codes, validating the QP as a crucial player in structure formation at small scales.
Energy Technology Data Exchange (ETDEWEB)
Liu, R. [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong (China); Zhou, W., E-mail: wenzzhou@cityu.edu.hk [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong (China); Shen, P. [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong (China); Prudil, A. [Fuel and Fuel Channel Safety Branch, Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Chan, P.K. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario (Canada)
2015-12-15
Highlights: • LWR fuel performance modeling capability developed. • Fully coupled multiphysics studies for enhanced thermal conductivity UO{sub 2}–BeO fuel. • UO{sub 2}–BeO fuel decreases fuel temperature and lessens thermal stresses. • UO{sub 2}–BeO fuel facilitates a reduction in PCMI. • Reactor safety can be improved for UO{sub 2}–BeO fuel. - Abstract: Commercial light water reactor fuel UO{sub 2} has a low thermal conductivity that leads to the development of a large temperature gradient across the fuel pellet, limiting the reactor operational performance due to the effects that include thermal stresses causing pellet cladding interaction and the release of fission product gases. This study presents the development of a modeling and simulation for enhanced thermal conductivity UO{sub 2}–BeO fuel behavior in a light water reactor, using self-defined multiple physics models fully coupled based on the framework of COMSOL Multiphysics. Almost all the related physical models are considered, including heat generation and conduction, species diffusion, thermomechanics (thermal expansion, elastic strain, densification, and fission product swelling strain), grain growth, fission gas production and release, gap heat transfer, mechanical contact, gap/plenum pressure with plenum volume, cladding thermal and irradiation creep and oxidation. All the phenomenal models and materials properties are implemented into COMSOL Multiphysics finite-element platform with a 2D axisymmetric geometry of a fuel pellet and cladding. UO{sub 2}–BeO enhanced thermal conductivity nuclear fuel would decrease fuel temperatures and facilitate a reduction in pellet cladding interaction from our simulation results through lessening thermal stresses that result in fuel cracking, relocation, and swelling, so that the safety of the reactor would be improved.
DEFF Research Database (Denmark)
Khan, Mohammad Rezwan; Kær, Søren Knudsen
2016-01-01
The research is focused on the development of a three-dimensional cell level multiphysics battery thermal model. The primary aim is to represent the cooling mechanism inside the unit cell battery pack. It is accomplished through the coupling of heat transfer and computational fluid dynamics (CFD......) physics. A lumped value of heat generation (HG) inside the battery cell is used. It stems from isothermal calorimeter experiment. HG depends on current rate and the corresponding operating temperature. It is demonstrated that the developed model provides a deeper understanding of the thermal spatio......-temporal behavior of Li-ion battery in different operating conditions....
DEFF Research Database (Denmark)
Andersen, Søren Bøgh; Santos, Ilmar F.; Fuerst, Axel
2015-01-01
This paper presents an improved completely interconnected procedure for estimating the losses, cooling flows, fluid characteristics and temperature distribution in a gearless mill drive using real life data. The presented model is part of a larger project building a multi-physics model combining...... iteratively according to the heat flux transferred to the fluid, is modeled as a lumped model with two nodes interconnected by 11 channels and one pump. The flow model is based on Bernoulli's energy equation and solved by Newton-Raphson method. All the results from the three physical areas have been verified...
DEFF Research Database (Denmark)
Soon, Winnie
2014-01-01
This essay studies the source code of an artwork from a software studies perspective. By examining code that come close to the approach of critical code studies (Marino, 2006), I trace the network artwork, Pupufu (Lin, 2009) to understand various real-time approaches to social media platforms (MSN......, Twitter and Facebook). The focus is not to investigate the functionalities and efficiencies of the code, but to study and interpret the program level of code in order to trace the use of various technological methods such as third-party libraries and platforms’ interfaces. These are important...... to understand the socio-technical side of a changing network environment. Through the study of code, including but not limited to source code, technical specifications and other materials in relation to the artwork production, I would like to explore the materiality of code that goes beyond technical...
Djordjevic, Ivan; Vasic, Bane
2010-01-01
This unique book provides a coherent and comprehensive introduction to the fundamentals of optical communications, signal processing and coding for optical channels. It is the first to integrate the fundamentals of coding theory and optical communication.
International Nuclear Information System (INIS)
Sacramento, A.M. do.
1989-01-01
This user's manual contains all the necessary information concerning the use of SEVERO code. This computer code is related to the statistics of extremes = extreme winds, extreme precipitation and flooding hazard risk analysis. (A.C.A.S.)
Whalen, Michael; Schumann, Johann; Fischer, Bernd
2002-01-01
Code certification is a lightweight approach for formally demonstrating software quality. Its basic idea is to require code producers to provide formal proofs that their code satisfies certain quality properties. These proofs serve as certificates that can be checked independently. Since code certification uses the same underlying technology as program verification, it requires detailed annotations (e.g., loop invariants) to make the proofs possible. However, manually adding annotations to th...
International Nuclear Information System (INIS)
Schmittroth, F.
1979-09-01
A documentation of the FERRET data analysis code is given. The code provides a way to combine related measurements and calculations in a consistent evaluation. Basically a very general least-squares code, it is oriented towards problems frequently encountered in nuclear data and reactor physics. A strong emphasis is on the proper treatment of uncertainties and correlations and in providing quantitative uncertainty estimates. Documentation includes a review of the method, structure of the code, input formats, and examples
Xu, Mingliang; Su, Hao; Li, Yafei; Li, Xi; Liao, Jing; Niu, Jianwei; Lv, Pei; Zhou, Bing
2018-01-01
With the continued proliferation of smart mobile devices, Quick Response (QR) code has become one of the most-used types of two-dimensional code in the world. Aiming at beautifying the appearance of QR codes, existing works have developed a series of techniques to make the QR code more visual-pleasant. However, these works still leave much to be desired, such as visual diversity, aesthetic quality, flexibility, universal property, and robustness. To address these issues, in this paper, we pro...
Zhang, Linfan; Zheng, Shuang
2015-01-01
Quick Response code opens possibility to convey data in a unique way yet insufficient prevention and protection might lead into QR code being exploited on behalf of attackers. This thesis starts by presenting a general introduction of background and stating two problems regarding QR code security, which followed by a comprehensive research on both QR code itself and related issues. From the research a solution taking advantages of cloud and cryptography together with an implementation come af...
DEFF Research Database (Denmark)
Steensig, Jakob; Heinemann, Trine
2015-01-01
doing formal coding and when doing more “traditional” conversation analysis research based on collections. We are more wary, however, of the implication that coding-based research is the end result of a process that starts with qualitative investigations and ends with categories that can be coded...
DEFF Research Database (Denmark)
Bombin Palomo, Hector
2015-01-01
Color codes are topological stabilizer codes with unusual transversality properties. Here I show that their group of transversal gates is optimal and only depends on the spatial dimension, not the local geometry. I also introduce a generalized, subsystem version of color codes. In 3D they allow...
A. van Deursen (Arie); L.M.F. Moonen (Leon); A. van den Bergh; G. Kok
2001-01-01
textabstractTwo key aspects of extreme programming (XP) are unit testing and merciless refactoring. Given the fact that the ideal test code / production code ratio approaches 1:1, it is not surprising that unit tests are being refactored. We found that refactoring test code is different from
Component-based framework for subsurface simulations
International Nuclear Information System (INIS)
Palmer, B J; Fang, Yilin; Hammond, Glenn; Gurumoorthi, Vidhya
2007-01-01
Simulations in the subsurface environment represent a broad range of phenomena covering an equally broad range of scales. Developing modelling capabilities that can integrate models representing different phenomena acting at different scales present formidable challenges both from the algorithmic and computer science perspective. This paper will describe the development of an integrated framework that will be used to combine different models into a single simulation. Initial work has focused on creating two frameworks, one for performing smooth particle hydrodynamics (SPH) simulations of fluid systems, the other for performing grid-based continuum simulations of reactive subsurface flow. The SPH framework is based on a parallel code developed for doing pore scale simulations, the continuum grid-based framework is based on the STOMP (Subsurface Transport Over Multiple Phases) code developed at PNNL Future work will focus on combining the frameworks together to perform multiscale, multiphysics simulations of reactive subsurface flow
Software Certification - Coding, Code, and Coders
Havelund, Klaus; Holzmann, Gerard J.
2011-01-01
We describe a certification approach for software development that has been adopted at our organization. JPL develops robotic spacecraft for the exploration of the solar system. The flight software that controls these spacecraft is considered to be mission critical. We argue that the goal of a software certification process cannot be the development of "perfect" software, i.e., software that can be formally proven to be correct under all imaginable and unimaginable circumstances. More realistically, the goal is to guarantee a software development process that is conducted by knowledgeable engineers, who follow generally accepted procedures to control known risks, while meeting agreed upon standards of workmanship. We target three specific issues that must be addressed in such a certification procedure: the coding process, the code that is developed, and the skills of the coders. The coding process is driven by standards (e.g., a coding standard) and tools. The code is mechanically checked against the standard with the help of state-of-the-art static source code analyzers. The coders, finally, are certified in on-site training courses that include formal exams.
International Nuclear Information System (INIS)
1997-01-01
The Network Code defines the rights and responsibilities of all users of the natural gas transportation system in the liberalised gas industry in the United Kingdom. This report describes the operation of the Code, what it means, how it works and its implications for the various participants in the industry. The topics covered are: development of the competitive gas market in the UK; key points in the Code; gas transportation charging; impact of the Code on producers upstream; impact on shippers; gas storage; supply point administration; impact of the Code on end users; the future. (20 tables; 33 figures) (UK)
Rice, R. F.; Lee, J. J.
1986-01-01
Scheme for coding facsimile messages promises to reduce data transmission requirements to one-tenth current level. Coding scheme paves way for true electronic mail in which handwritten, typed, or printed messages or diagrams sent virtually instantaneously - between buildings or between continents. Scheme, called Universal System for Efficient Electronic Mail (USEEM), uses unsupervised character recognition and adaptive noiseless coding of text. Image quality of resulting delivered messages improved over messages transmitted by conventional coding. Coding scheme compatible with direct-entry electronic mail as well as facsimile reproduction. Text transmitted in this scheme automatically translated to word-processor form.
International Nuclear Information System (INIS)
Mueller, W.H.; Schneider, B.; Staeuble, J.
1984-01-01
This reference manual provides users of the NAGRADATA system with comprehensive keys to the coding/decoding of geological and technical information to be stored in or retreaved from the databank. Emphasis has been placed on input data coding. When data is retreaved the translation into plain language of stored coded information is done automatically by computer. Three keys each, list the complete set of currently defined codes for the NAGRADATA system, namely codes with appropriate definitions, arranged: 1. according to subject matter (thematically) 2. the codes listed alphabetically and 3. the definitions listed alphabetically. Additional explanation is provided for the proper application of the codes and the logic behind the creation of new codes to be used within the NAGRADATA system. NAGRADATA makes use of codes instead of plain language for data storage; this offers the following advantages: speed of data processing, mainly data retrieval, economies of storage memory requirements, the standardisation of terminology. The nature of this thesaurian type 'key to codes' makes it impossible to either establish a final form or to cover the entire spectrum of requirements. Therefore, this first issue of codes to NAGRADATA must be considered to represent the current state of progress of a living system and future editions will be issued in a loose leave ringbook system which can be updated by an organised (updating) service. (author)
International Nuclear Information System (INIS)
Jow, Hong-Nian; Murfin, W.B.; Johnson, J.D.
1993-11-01
This report describes the source term estimation codes, XSORs. The codes are written for three pressurized water reactors (Surry, Sequoyah, and Zion) and two boiling water reactors (Peach Bottom and Grand Gulf). The ensemble of codes has been named ''XSOR''. The purpose of XSOR codes is to estimate the source terms which would be released to the atmosphere in severe accidents. A source term includes the release fractions of several radionuclide groups, the timing and duration of releases, the rates of energy release, and the elevation of releases. The codes have been developed by Sandia National Laboratories for the US Nuclear Regulatory Commission (NRC) in support of the NUREG-1150 program. The XSOR codes are fast running parametric codes and are used as surrogates for detailed mechanistic codes. The XSOR codes also provide the capability to explore the phenomena and their uncertainty which are not currently modeled by the mechanistic codes. The uncertainty distributions of input parameters may be used by an. XSOR code to estimate the uncertainty of source terms
International Nuclear Information System (INIS)
Kulikowska, T.
1999-01-01
The present lecture has a main goal to show how the transport lattice calculations are realised in a standard computer code. This is illustrated on the example of the WIMSD code, belonging to the most popular tools for reactor calculations. Most of the approaches discussed here can be easily modified to any other lattice code. The description of the code assumes the basic knowledge of reactor lattice, on the level given in the lecture on 'Reactor lattice transport calculations'. For more advanced explanation of the WIMSD code the reader is directed to the detailed descriptions of the code cited in References. The discussion of the methods and models included in the code is followed by the generally used homogenisation procedure and several numerical examples of discrepancies in calculated multiplication factors based on different sources of library data. (author)
Energy Technology Data Exchange (ETDEWEB)
2014-05-14
DLLExternalCode is the a general dynamic-link library (DLL) interface for linking GoldSim (www.goldsim.com) with external codes. The overall concept is to use GoldSim as top level modeling software with interfaces to external codes for specific calculations. The DLLExternalCode DLL that performs the linking function is designed to take a list of code inputs from GoldSim, create an input file for the external application, run the external code, and return a list of outputs, read from files created by the external application, back to GoldSim. Instructions for creating the input file, running the external code, and reading the output are contained in an instructions file that is read and interpreted by the DLL.
Verification of CTF/PARCSv3.2 coupled code in a Turbine Trip scenario
International Nuclear Information System (INIS)
Abarca, A.; Hidalga, P.; Miro, R.; Verdu, G.; Sekhri, A.
2017-01-01
Multiphysics codes had revealed as a best-estimate approach to simulate core behavior in LWR. Coupled neutronics and thermal-hydraulics codes are being used and improved to achieve reliable results for reactor safety transient analysis. The implementation of the feedback procedure between the coupled codes at each time step allows a more accurate simulation and a better prediction of the safety limits of analyzed scenarios. With the objective of testing the recently developed CTF/PARCSv3.2 coupled code, a code-to-code verification against TRACE has been developed in a BWR Turbine Trip scenario. CTF is a thermal-hydraulic subchannel code that features two-fluid, three-field representation of the two-phase flow, while PARCS code solves the neutronic diffusion equation in a 3D nodal distribution. PARCS features allow as well the use of extended sets of cross section libraries for a more precise neutronic performance in different formats like PMAX or NEMTAB. Using this option the neutronic core composition of KKL will be made taking advantage of the core follow database. The results of the simulation will be verified against TRACE results. TRACE will be used as a reference code for the validation process since it has been a recommended code by the USNRC. The model used for TRACE includes a full core plus relevant components such as the steam lines and the valves affecting and controlling the turbine trip evolution. The coupled code performance has been evaluated using the Turbine Trip event that took place in Kern Kraftwerk Leibstadt (KKL), at the fuel cycle 18. KKL is a Nuclear Power Plant (NPP) located in Leibstadt, Switzerland. This NPP operates with a BWR developing 3600 MWt in fuel cycles of one year. The Turbine Trip is a fast transient developing a pressure peak in the reactor followed by a power decreasing due to the selected control rod insertion. This kind of transient is very useful to check the feedback performance between both coupled codes due to the fast
Numerical verification of equilibrium chemistry software within nuclear fuel performance codes
International Nuclear Information System (INIS)
Piro, M.H.; Lewis, B.J.; Thompson, W.T.; Simunovic, S.; Besmann, T.M.
2010-01-01
A numerical tool is in an advanced state of development to compute the equilibrium compositions of phases and their proportions in multi-component systems of importance to the nuclear industry. The resulting software is being conceived for direct integration into large multi-physics fuel performance codes, particularly for providing transport source terms, material properties, and boundary conditions in heat and mass transport modules. Consequently, any numerical errors produced in equilibrium chemistry computations will be propagated in subsequent heat and mass transport calculations, thus falsely predicting nuclear fuel behaviour. The necessity for a reliable method to numerically verify chemical equilibrium computations is emphasized by the requirement to handle the very large number of elements necessary to capture the entire fission product inventory. A simple, reliable and comprehensive numerical verification method called the Gibbs Criteria is presented which can be invoked by any equilibrium chemistry solver for quality assurance purposes. (author)
Toric Varieties and Codes, Error-correcting Codes, Quantum Codes, Secret Sharing and Decoding
DEFF Research Database (Denmark)
Hansen, Johan Peder
We present toric varieties and associated toric codes and their decoding. Toric codes are applied to construct Linear Secret Sharing Schemes (LSSS) with strong multiplication by the Massey construction. Asymmetric Quantum Codes are obtained from toric codes by the A.R. Calderbank P.W. Shor and A.......M. Steane construction of stabilizer codes (CSS) from linear codes containing their dual codes....
An Optimal Linear Coding for Index Coding Problem
Pezeshkpour, Pouya
2015-01-01
An optimal linear coding solution for index coding problem is established. Instead of network coding approach by focus on graph theoric and algebraic methods a linear coding program for solving both unicast and groupcast index coding problem is presented. The coding is proved to be the optimal solution from the linear perspective and can be easily utilize for any number of messages. The importance of this work is lying mostly on the usage of the presented coding in the groupcast index coding ...
Energy Technology Data Exchange (ETDEWEB)
Wang, R. C.; Xu, Y.; Downar, T. [Dept. of Nuclear Engineering and Radiological Sciences, Univ. of Michigan, Ann Arbor, MI 48104 (United States); Hudson, N. [RES Div., U.S. NRC, Rockville, MD (United States)
2012-07-01
The Special Power Excursion Reactor Test III (SPERT III) was a series of reactivity insertion experiments conducted in the 1950's. This paper describes the validation of the U.S. NRC Coupled Code system TRITON/PARCS/TRACE to simulate reactivity insertion accidents (RIA) by using several of the SPERT III tests. The work here used the SPERT III E-core configuration tests in which the RIA was initiated by ejecting a control rod. The resulting super-prompt reactivity excursion and negative reactivity feedback produced the familiar bell shaped power increase and decrease. The energy deposition during such a power peak has important safety consequences and provides validation basis for core coupled multi-physics codes. The transients of five separate tests are used to benchmark the PARCS/TRACE coupled code. The models were thoroughly validated using the original experiment documentation. (authors)
DEFF Research Database (Denmark)
Andersen, Christian Ulrik
2007-01-01
Computer art is often associated with computer-generated expressions (digitally manipulated audio/images in music, video, stage design, media facades, etc.). In recent computer art, however, the code-text itself – not the generated output – has become the artwork (Perl Poetry, ASCII Art, obfuscated...... code, etc.). The presentation relates this artistic fascination of code to a media critique expressed by Florian Cramer, claiming that the graphical interface represents a media separation (of text/code and image) causing alienation to the computer’s materiality. Cramer is thus the voice of a new ‘code...... avant-garde’. In line with Cramer, the artists Alex McLean and Adrian Ward (aka Slub) declare: “art-oriented programming needs to acknowledge the conditions of its own making – its poesis.” By analysing the Live Coding performances of Slub (where they program computer music live), the presentation...
International Nuclear Information System (INIS)
Bravyi, Sergey; Terhal, Barbara M; Leemhuis, Bernhard
2010-01-01
We initiate the study of Majorana fermion codes (MFCs). These codes can be viewed as extensions of Kitaev's one-dimensional (1D) model of unpaired Majorana fermions in quantum wires to higher spatial dimensions and interacting fermions. The purpose of MFCs is to protect quantum information against low-weight fermionic errors, that is, operators acting on sufficiently small subsets of fermionic modes. We examine to what extent MFCs can surpass qubit stabilizer codes in terms of their stability properties. A general construction of 2D MFCs is proposed that combines topological protection based on a macroscopic code distance with protection based on fermionic parity conservation. Finally, we use MFCs to show how to transform any qubit stabilizer code to a weakly self-dual CSS code.
Elder, D
1984-06-07
The logic of genetic control of development may be based on a binary epigenetic code. This paper revises the author's previous scheme dealing with the numerology of annelid metamerism in these terms. Certain features of the code had been deduced to be combinatorial, others not. This paradoxical contrast is resolved here by the interpretation that these features relate to different operations of the code; the combinatiorial to coding identity of units, the non-combinatorial to coding production of units. Consideration of a second paradox in the theory of epigenetic coding leads to a new solution which further provides a basis for epimorphic regeneration, and may in particular throw light on the "regeneration-duplication" phenomenon. A possible test of the model is also put forward.
International Nuclear Information System (INIS)
Vokac, P.
1999-12-01
DISP1 code is a simple tool for assessment of the dispersion of the fission product cloud escaping from a nuclear power plant after an accident. The code makes it possible to tentatively check the feasibility of calculations by more complex PSA3 codes and/or codes for real-time dispersion calculations. The number of input parameters is reasonably low and the user interface is simple enough to allow a rapid processing of sensitivity analyses. All input data entered through the user interface are stored in the text format. Implementation of dispersion model corrections taken from the ARCON96 code enables the DISP1 code to be employed for assessment of the radiation hazard within the NPP area, in the control room for instance. (P.A.)
Phonological coding during reading.
Leinenger, Mallorie
2014-11-01
The exact role that phonological coding (the recoding of written, orthographic information into a sound based code) plays during silent reading has been extensively studied for more than a century. Despite the large body of research surrounding the topic, varying theories as to the time course and function of this recoding still exist. The present review synthesizes this body of research, addressing the topics of time course and function in tandem. The varying theories surrounding the function of phonological coding (e.g., that phonological codes aid lexical access, that phonological codes aid comprehension and bolster short-term memory, or that phonological codes are largely epiphenomenal in skilled readers) are first outlined, and the time courses that each maps onto (e.g., that phonological codes come online early [prelexical] or that phonological codes come online late [postlexical]) are discussed. Next the research relevant to each of these proposed functions is reviewed, discussing the varying methodologies that have been used to investigate phonological coding (e.g., response time methods, reading while eye-tracking or recording EEG and MEG, concurrent articulation) and highlighting the advantages and limitations of each with respect to the study of phonological coding. In response to the view that phonological coding is largely epiphenomenal in skilled readers, research on the use of phonological codes in prelingually, profoundly deaf readers is reviewed. Finally, implications for current models of word identification (activation-verification model, Van Orden, 1987; dual-route model, e.g., M. Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001; parallel distributed processing model, Seidenberg & McClelland, 1989) are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
Energy Technology Data Exchange (ETDEWEB)
Visser, B. [Stork Product Eng., Amsterdam (Netherlands)
1996-09-01
To support the discussion on aeroelastic codes, a description of the code FLEXLAST was given and experiences within benchmarks and measurement programmes were summarized. The code FLEXLAST has been developed since 1982 at Stork Product Engineering (SPE). Since 1992 FLEXLAST has been used by Dutch industries for wind turbine and rotor design. Based on the comparison with measurements, it can be concluded that the main shortcomings of wind turbine modelling lie in the field of aerodynamics, wind field and wake modelling. (au)
International Nuclear Information System (INIS)
Pastore, G.; Hales, J.D.; Novascone, S.R.; Perez, D.M.; Spencer, B.W.; Williamson, R.L.
2014-01-01
BISON is a modern finite-element based, multidimensional nuclear fuel performance code that has been under development at Idaho National Laboratory (USA) since 2009. The capabilities of BISON comprise implicit solution of the fully coupled thermo-mechanics and diffusion equations, applicability to a variety of fuel forms, and simulation of both steady-state and transient conditions. The code includes multiphysics constitutive behavior for both fuel and cladding materials, and is designed for efficient use on highly parallel computers. This paper describes the main features of BISON, with emphasis on recent developments in modelling of fission gas behaviour in LWR-UO 2 fuel. The code is applied to the simulation of fuel rod irradiation experiments from the OECD/NEA International Fuel Performance Experiments Database. The comparison of the results with the available experimental data of fuel temperature, fission gas release, and cladding diametrical strain during pellet-cladding mechanical interaction is presented, pointing out a promising potential of the BISON code with the new fission gas behaviour model. (authors)
International Nuclear Information System (INIS)
Cramer, S.N.
1984-01-01
The MORSE code is a large general-use multigroup Monte Carlo code system. Although no claims can be made regarding its superiority in either theoretical details or Monte Carlo techniques, MORSE has been, since its inception at ORNL in the late 1960s, the most widely used Monte Carlo radiation transport code. The principal reason for this popularity is that MORSE is relatively easy to use, independent of any installation or distribution center, and it can be easily customized to fit almost any specific need. Features of the MORSE code are described
Waters, Joe
2012-01-01
Find out how to effectively create, use, and track QR codes QR (Quick Response) codes are popping up everywhere, and businesses are reaping the rewards. Get in on the action with the no-nonsense advice in this streamlined, portable guide. You'll find out how to get started, plan your strategy, and actually create the codes. Then you'll learn to link codes to mobile-friendly content, track your results, and develop ways to give your customers value that will keep them coming back. It's all presented in the straightforward style you've come to know and love, with a dash of humor thrown
International Nuclear Information System (INIS)
Reid, R.L.; Barrett, R.J.; Brown, T.G.
1985-03-01
The FEDC Tokamak Systems Code calculates tokamak performance, cost, and configuration as a function of plasma engineering parameters. This version of the code models experimental tokamaks. It does not currently consider tokamak configurations that generate electrical power or incorporate breeding blankets. The code has a modular (or subroutine) structure to allow independent modeling for each major tokamak component or system. A primary benefit of modularization is that a component module may be updated without disturbing the remainder of the systems code as long as the imput to or output from the module remains unchanged
Efficient Coding of Information: Huffman Coding -RE ...
Indian Academy of Sciences (India)
to a stream of equally-likely symbols so as to recover the original stream in the event of errors. The for- ... The source-coding problem is one of finding a mapping from U to a ... probability that the random variable X takes the value x written as ...
NR-code: Nonlinear reconstruction code
Yu, Yu; Pen, Ue-Li; Zhu, Hong-Ming
2018-04-01
NR-code applies nonlinear reconstruction to the dark matter density field in redshift space and solves for the nonlinear mapping from the initial Lagrangian positions to the final redshift space positions; this reverses the large-scale bulk flows and improves the precision measurement of the baryon acoustic oscillations (BAO) scale.
Directory of Open Access Journals (Sweden)
Roger P. Pawlowski
2012-01-01
Full Text Available An approach for incorporating embedded simulation and analysis capabilities in complex simulation codes through template-based generic programming is presented. This approach relies on templating and operator overloading within the C++ language to transform a given calculation into one that can compute a variety of additional quantities that are necessary for many state-of-the-art simulation and analysis algorithms. An approach for incorporating these ideas into complex simulation codes through general graph-based assembly is also presented. These ideas have been implemented within a set of packages in the Trilinos framework and are demonstrated on a simple problem from chemical engineering.
Whalen, Michael; Schumann, Johann; Fischer, Bernd
2002-01-01
Code certification is a lightweight approach to demonstrate software quality on a formal level. Its basic idea is to require producers to provide formal proofs that their code satisfies certain quality properties. These proofs serve as certificates which can be checked independently. Since code certification uses the same underlying technology as program verification, it also requires many detailed annotations (e.g., loop invariants) to make the proofs possible. However, manually adding theses annotations to the code is time-consuming and error-prone. We address this problem by combining code certification with automatic program synthesis. We propose an approach to generate simultaneously, from a high-level specification, code and all annotations required to certify generated code. Here, we describe a certification extension of AUTOBAYES, a synthesis tool which automatically generates complex data analysis programs from compact specifications. AUTOBAYES contains sufficient high-level domain knowledge to generate detailed annotations. This allows us to use a general-purpose verification condition generator to produce a set of proof obligations in first-order logic. The obligations are then discharged using the automated theorem E-SETHEO. We demonstrate our approach by certifying operator safety for a generated iterative data classification program without manual annotation of the code.
Division for Early Childhood, Council for Exceptional Children, 2009
2009-01-01
The Code of Ethics of the Division for Early Childhood (DEC) of the Council for Exceptional Children is a public statement of principles and practice guidelines supported by the mission of DEC. The foundation of this Code is based on sound ethical reasoning related to professional practice with young children with disabilities and their families…
Interleaved Product LDPC Codes
Baldi, Marco; Cancellieri, Giovanni; Chiaraluce, Franco
2011-01-01
Product LDPC codes take advantage of LDPC decoding algorithms and the high minimum distance of product codes. We propose to add suitable interleavers to improve the waterfall performance of LDPC decoding. Interleaving also reduces the number of low weight codewords, that gives a further advantage in the error floor region.
Napier, Rebecca H; Bruelheide, Lori S; Demann, Eric T K; Haug, Richard H
2008-07-01
The purpose of this article is to highlight the importance of understanding various numeric and alpha-numeric codes for accurately billing dental and medically related services to private pay or third-party insurance carriers. In the United States, common dental terminology (CDT) codes are most commonly used by dentists to submit claims, whereas current procedural terminology (CPT) and International Classification of Diseases, Ninth Revision, Clinical Modification (ICD.9.CM) codes are more commonly used by physicians to bill for their services. The CPT and ICD.9.CM coding systems complement each other in that CPT codes provide the procedure and service information and ICD.9.CM codes provide the reason or rationale for a particular procedure or service. These codes are more commonly used for "medical necessity" determinations, and general dentists and specialists who routinely perform care, including trauma-related care, biopsies, and dental treatment as a result of or in anticipation of a cancer-related treatment, are likely to use these codes. Claim submissions for care provided can be completed electronically or by means of paper forms.
Indian Academy of Sciences (India)
Science and Automation at ... the Reed-Solomon code contained 223 bytes of data, (a byte ... then you have a data storage system with error correction, that ..... practical codes, storing such a table is infeasible, as it is generally too large.
DEFF Research Database (Denmark)
Pries-Heje, Lene; Pries-Heje, Jan; Dalgaard, Bente
2013-01-01
is required. In this paper we present the design of such a new approach, the Scrum Code Camp, which can be used to assess agile team capability in a transparent and consistent way. A design science research approach is used to analyze properties of two instances of the Scrum Code Camp where seven agile teams...
International Nuclear Information System (INIS)
Lysenko, W.P.
1984-04-01
We have developed the RFQLIB simulation system to provide a means to systematically generate the new versions of radio-frequency quadrupole (RFQ) linac simulation codes that are required by the constantly changing needs of a research environment. This integrated system simplifies keeping track of the various versions of the simulation code and makes it practical to maintain complete and up-to-date documentation. In this scheme, there is a certain standard version of the simulation code that forms a library upon which new versions are built. To generate a new version of the simulation code, the routines to be modified or added are appended to a standard command file, which contains the commands to compile the new routines and link them to the routines in the library. The library itself is rarely changed. Whenever the library is modified, however, this modification is seen by all versions of the simulation code, which actually exist as different versions of the command file. All code is written according to the rules of structured programming. Modularity is enforced by not using COMMON statements, simplifying the relation of the data flow to a hierarchy diagram. Simulation results are similar to those of the PARMTEQ code, as expected, because of the similar physical model. Different capabilities, such as those for generating beams matched in detail to the structure, are available in the new code for help in testing new ideas in designing RFQ linacs
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 3. Error Correcting Codes - Reed Solomon Codes. Priti Shankar. Series Article Volume 2 Issue 3 March ... Author Affiliations. Priti Shankar1. Department of Computer Science and Automation, Indian Institute of Science, Bangalore 560 012, India ...
2013-03-26
... Energy Conservation Code. International Existing Building Code. International Fire Code. International... Code. International Property Maintenance Code. International Residential Code. International Swimming Pool and Spa Code International Wildland-Urban Interface Code. International Zoning Code. ICC Standards...
Validation of thermalhydraulic codes
International Nuclear Information System (INIS)
Wilkie, D.
1992-01-01
Thermalhydraulic codes require to be validated against experimental data collected over a wide range of situations if they are to be relied upon. A good example is provided by the nuclear industry where codes are used for safety studies and for determining operating conditions. Errors in the codes could lead to financial penalties, to the incorrect estimation of the consequences of accidents and even to the accidents themselves. Comparison between prediction and experiment is often described qualitatively or in approximate terms, e.g. ''agreement is within 10%''. A quantitative method is preferable, especially when several competing codes are available. The codes can then be ranked in order of merit. Such a method is described. (Author)
International Nuclear Information System (INIS)
Dershowitz, W; Herbert, A.; Long, J.
1989-03-01
The hydrology of the SCV site will be modelled utilizing discrete fracture flow models. These models are complex, and can not be fully cerified by comparison to analytical solutions. The best approach for verification of these codes is therefore cross-verification between different codes. This is complicated by the variation in assumptions and solution techniques utilized in different codes. Cross-verification procedures are defined which allow comparison of the codes developed by Harwell Laboratory, Lawrence Berkeley Laboratory, and Golder Associates Inc. Six cross-verification datasets are defined for deterministic and stochastic verification of geometric and flow features of the codes. Additional datasets for verification of transport features will be documented in a future report. (13 figs., 7 tabs., 10 refs.) (authors)
Development of a dynamic coupled hydro-geomechanical code and its application to induced seismicity
Miah, Md Mamun
This research describes the importance of a hydro-geomechanical coupling in the geologic sub-surface environment from fluid injection at geothermal plants, large-scale geological CO2 sequestration for climate mitigation, enhanced oil recovery, and hydraulic fracturing during wells construction in the oil and gas industries. A sequential computational code is developed to capture the multiphysics interaction behavior by linking a flow simulation code TOUGH2 and a geomechanics modeling code PyLith. Numerical formulation of each code is discussed to demonstrate their modeling capabilities. The computational framework involves sequential coupling, and solution of two sub-problems- fluid flow through fractured and porous media and reservoir geomechanics. For each time step of flow calculation, pressure field is passed to the geomechanics code to compute effective stress field and fault slips. A simplified permeability model is implemented in the code that accounts for the permeability of porous and saturated rocks subject to confining stresses. The accuracy of the TOUGH-PyLith coupled simulator is tested by simulating Terzaghi's 1D consolidation problem. The modeling capability of coupled poroelasticity is validated by benchmarking it against Mandel's problem. The code is used to simulate both quasi-static and dynamic earthquake nucleation and slip distribution on a fault from the combined effect of far field tectonic loading and fluid injection by using an appropriate fault constitutive friction model. Results from the quasi-static induced earthquake simulations show a delayed response in earthquake nucleation. This is attributed to the increased total stress in the domain and not accounting for pressure on the fault. However, this issue is resolved in the final chapter in simulating a single event earthquake dynamic rupture. Simulation results show that fluid pressure has a positive effect on slip nucleation and subsequent crack propagation. This is confirmed by
Perronet, Alexandra
2011-01-01
La phase actuelle d’accumulation capitalistique tend à faire de la consommation non seulement une sphère de reproduction des rapports sociaux, mais un lieu de production des forces de travail. Partant de ce postulat, cet article se propose de montrer comment les pratiques de consommation structurent les rapports sociaux de production. Selon l’auteur, il s'agit d'une question à la fois pratique et symbolique : la consommation déterminant tant l'organisation des rapports sociaux que le développ...
Energy Technology Data Exchange (ETDEWEB)
Bary, B.
2010-09-15
This document is a synthesis of the applied research studies undertaken by the author during ten years, first at the University of Marne-La-Vallee during the period 1999-2002, then at the CEA. These studies concern the modeling and the numerical simulations of the cementitious materials behavior subjected on the one hand to moderate thermomechanical and hydric loadings, and on the other hand to chemical attacks due to the migration of calcium, carbonate and sulfate ions. The developed approaches may be viewed as multi-physical in the sense that the models used for describing the behavior couple various fields and phenomena such as mechanics, thermal, hydric and ionic transfers, and chemistry. In addition, analytical up-scaling techniques are applied to estimate the physical properties associated with these phenomena (mechanical, hydraulic and diffusive parameters) as a function of the microstructure and the hydric state of the material. (author)
International Nuclear Information System (INIS)
Luo, Quantian; Tong, Liyong
2011-01-01
This paper presents a novel finite element formulation for 0–3 polarized PbLaZrTi (PLZT) plates and a comparison of the predicted and measured bending displacements. The coupled multi-physics fields and Hamilton's principle for piezoelectric (PZT) materials are first extended to PLZT ceramics by including the anomalous photovoltaic and photo-thermal effects. The photo-induced non-uniform electrical field and mechanical strains across the thickness are modeled in the present finite element formulation for 0–3 polarized PLZT plates, and the associated actuator and sensor equations are derived. The transverse displacements of a 0–3 polarized PLZT plate are predicted using the present finite element formulation and compared with the measured data given in part I. A reasonably good correlation is noted for the transverse displacements at the ten measurement points
Huffman coding in advanced audio coding standard
Brzuchalski, Grzegorz
2012-05-01
This article presents several hardware architectures of Advanced Audio Coding (AAC) Huffman noiseless encoder, its optimisations and working implementation. Much attention has been paid to optimise the demand of hardware resources especially memory size. The aim of design was to get as short binary stream as possible in this standard. The Huffman encoder with whole audio-video system has been implemented in FPGA devices.
Bi, Linfeng
2009-01-01
The main challenges in modeling fluid flow through naturally-fractured carbonate karst reservoirs are how to address various flow physics in complex geological architectures due to the presence of vugs and caves which are connected via fracture networks at multiple scales. In this paper, we present a unified multi-physics model that adapts to the complex flow regime through naturally-fractured carbonate karst reservoirs. This approach generalizes Stokes-Brinkman model (Popov et al. 2007). The fracture networks provide the essential connection between the caves in carbonate karst reservoirs. It is thus very important to resolve the flow in fracture network and the interaction between fractures and caves to better understand the complex flow behavior. The idea is to use Stokes-Brinkman model to represent flow through rock matrix, void caves as well as intermediate flows in very high permeability regions and to use an idea similar to discrete fracture network model to represent flow in fracture network. Consequently, various numerical solution strategies can be efficiently applied to greatly improve the computational efficiency in flow simulations. We have applied this unified multi-physics model as a fine-scale flow solver in scale-up computations. Both local and global scale-up are considered. It is found that global scale-up has much more accurate than local scale-up. Global scale-up requires the solution of global flow problems on fine grid, which generally is computationally expensive. The proposed model has the ability to deal with large number of fractures and caves, which facilitate the application of Stokes-Brinkman model in global scale-up computation. The proposed model flexibly adapts to the different flow physics in naturally-fractured carbonate karst reservoirs in a simple and effective way. It certainly extends modeling and predicting capability in efficient development of this important type of reservoir.
Energy Technology Data Exchange (ETDEWEB)
Nelson, R.N. (ed.)
1985-05-01
This publication lists all report number codes processed by the Office of Scientific and Technical Information. The report codes are substantially based on the American National Standards Institute, Standard Technical Report Number (STRN)-Format and Creation Z39.23-1983. The Standard Technical Report Number (STRN) provides one of the primary methods of identifying a specific technical report. The STRN consists of two parts: The report code and the sequential number. The report code identifies the issuing organization, a specific program, or a type of document. The sequential number, which is assigned in sequence by each report issuing entity, is not included in this publication. Part I of this compilation is alphabetized by report codes followed by issuing installations. Part II lists the issuing organization followed by the assigned report code(s). In both Parts I and II, the names of issuing organizations appear for the most part in the form used at the time the reports were issued. However, for some of the more prolific installations which have had name changes, all entries have been merged under the current name.
International Nuclear Information System (INIS)
Nelson, R.N.
1985-05-01
This publication lists all report number codes processed by the Office of Scientific and Technical Information. The report codes are substantially based on the American National Standards Institute, Standard Technical Report Number (STRN)-Format and Creation Z39.23-1983. The Standard Technical Report Number (STRN) provides one of the primary methods of identifying a specific technical report. The STRN consists of two parts: The report code and the sequential number. The report code identifies the issuing organization, a specific program, or a type of document. The sequential number, which is assigned in sequence by each report issuing entity, is not included in this publication. Part I of this compilation is alphabetized by report codes followed by issuing installations. Part II lists the issuing organization followed by the assigned report code(s). In both Parts I and II, the names of issuing organizations appear for the most part in the form used at the time the reports were issued. However, for some of the more prolific installations which have had name changes, all entries have been merged under the current name
2014-01-01
While cracking a code might seem like something few of us would encounter in our daily lives, it is actually far more prevalent than we may realize. Anyone who has had personal information taken because of a hacked email account can understand the need for cryptography and the importance of encryption-essentially the need to code information to keep it safe. This detailed volume examines the logic and science behind various ciphers, their real world uses, how codes can be broken, and the use of technology in this oft-overlooked field.
Coded Splitting Tree Protocols
DEFF Research Database (Denmark)
Sørensen, Jesper Hemming; Stefanovic, Cedomir; Popovski, Petar
2013-01-01
This paper presents a novel approach to multiple access control called coded splitting tree protocol. The approach builds on the known tree splitting protocols, code structure and successive interference cancellation (SIC). Several instances of the tree splitting protocol are initiated, each...... instance is terminated prematurely and subsequently iterated. The combined set of leaves from all the tree instances can then be viewed as a graph code, which is decodable using belief propagation. The main design problem is determining the order of splitting, which enables successful decoding as early...
International Nuclear Information System (INIS)
Clancy, B.E.
1986-01-01
This chapter begins with a neutron transport equation which includes the one dimensional plane geometry problems, the one dimensional spherical geometry problems, and numerical solutions. The section on the ANISN code and its look-alikes covers problems which can be solved; eigenvalue problems; outer iteration loop; inner iteration loop; and finite difference solution procedures. The input and output data for ANISN is also discussed. Two dimensional problems such as the DOT code are given. Finally, an overview of the Monte-Carlo methods and codes are elaborated on
International Nuclear Information System (INIS)
Burkhard, N.R.
1979-01-01
The gravity inversion code applies stabilized linear inverse theory to determine the topography of a subsurface density anomaly from Bouguer gravity data. The gravity inversion program consists of four source codes: SEARCH, TREND, INVERT, and AVERAGE. TREND and INVERT are used iteratively to converge on a solution. SEARCH forms the input gravity data files for Nevada Test Site data. AVERAGE performs a covariance analysis on the solution. This document describes the necessary input files and the proper operation of the code. 2 figures, 2 tables
International Nuclear Information System (INIS)
Ivanov, A.; Sanchez, V.; Stieglitz, R.; Ivanov, K.
2014-01-01
Highlights: • The current paper focuses on a optimized method for performing coupled Monte-Carlo/thermal–hydraulics calculations. • Innovative on-the-fly method for supplying the temperature and density distributions is presented. • Convergence acceleration method is presented. It is proven applicable by generalizing the Robbins-Monro theorem. • Tallying is optimized by using collision probability estimator for the power profile estimation. - Abstract: In order to increase the accuracy and the degree of spatial and energy resolution of core design studies, coupled 3D neutronic (multi-group deterministic and continuous energy Monte-Carlo) and 3D thermal–hydraulic (CFD and subchannel) codes are being developed worldwide. At KIT, both deterministic and Monte-Carlo codes were coupled with subchannel codes and applied to predict the safety-related design parameters such as minimal critical power ratio (MCPR), maximal cladding and fuel temperature, departure from nuclide boiling ratio (DNBR). These coupling approaches were revised and considerably improved. Innovative method of internal on-the-fly thermal feedback interchange between the codes was implemented. It no longer relies on explicit material definitions and allows the modeling of temperature and density distributions based on the cell coordinates. In contrast to all existing coupled schemes, this method uses only standard MCNP geometry input and requires only proper definition of the geometrical dimensions. The initial material definition is arbitrary and is determined on-the-fly during the neutron transport by the thermal–hydraulic feedback. Another key issue addressed is the optimal application of parallel computing and the implementation of less time consuming tally estimators. Using multi-processor computer architectures and implementing collision density flux estimator, it is possible to reduce the Monte-Carlo running time and obtain converged results within reasonable time limit. The coupled
DEFF Research Database (Denmark)
2015-01-01
Fulcrum network codes, which are a network coding framework, achieve three objectives: (i) to reduce the overhead per coded packet to almost 1 bit per source packet; (ii) to operate the network using only low field size operations at intermediate nodes, dramatically reducing complexity...... in the network; and (iii) to deliver an end-to-end performance that is close to that of a high field size network coding system for high-end receivers while simultaneously catering to low-end ones that can only decode in a lower field size. Sources may encode using a high field size expansion to increase...... the number of dimensions seen by the network using a linear mapping. Receivers can tradeoff computational effort with network delay, decoding in the high field size, the low field size, or a combination thereof....
Supervised Convolutional Sparse Coding
Affara, Lama Ahmed; Ghanem, Bernard; Wonka, Peter
2018-01-01
coding, which aims at learning discriminative dictionaries instead of purely reconstructive ones. We incorporate a supervised regularization term into the traditional unsupervised CSC objective to encourage the final dictionary elements
International Nuclear Information System (INIS)
Dunn, F.E.; Prohammer, F.G.; Weber, D.P.
1983-01-01
The SASSYS LMFBR systems analysis code is being developed mainly to analyze the behavior of the shut-down heat-removal system and the consequences of failures in the system, although it is also capable of analyzing a wide range of transients, from mild operational transients through more severe transients leading to sodium boiling in the core and possible melting of clad and fuel. The code includes a detailed SAS4A multi-channel core treatment plus a general thermal-hydraulic treatment of the primary and intermediate heat-transport loops and the steam generators. The code can handle any LMFBR design, loop or pool, with an arbitrary arrangement of components. The code is fast running: usually faster than real time
Montgomery County of Maryland — The Office of the County Attorney (OCA) processes Code Violation Citations issued by County agencies. The citations can be viewed by issued department, issued date...
Energy Technology Data Exchange (ETDEWEB)
Freeman, L.N.; Wilson, R.E. [Oregon State Univ., Dept. of Mechanical Engineering, Corvallis, OR (United States)
1996-09-01
The FAST Code which is capable of determining structural loads on a flexible, teetering, horizontal axis wind turbine is described and comparisons of calculated loads with test data are given at two wind speeds for the ESI-80. The FAST Code models a two-bladed HAWT with degrees of freedom for blade bending, teeter, drive train flexibility, yaw, and windwise and crosswind tower motion. The code allows blade dimensions, stiffnesses, and weights to differ and models tower shadow, wind shear, and turbulence. Additionally, dynamic stall is included as are delta-3 and an underslung rotor. Load comparisons are made with ESI-80 test data in the form of power spectral density, rainflow counting, occurrence histograms, and azimuth averaged bin plots. It is concluded that agreement between the FAST Code and test results is good. (au)
Code Disentanglement: Initial Plan
Energy Technology Data Exchange (ETDEWEB)
Wohlbier, John Greaton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kelley, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rockefeller, Gabriel M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Calef, Matthew Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-01-27
The first step to making more ambitious changes in the EAP code base is to disentangle the code into a set of independent, levelized packages. We define a package as a collection of code, most often across a set of files, that provides a defined set of functionality; a package a) can be built and tested as an entity and b) fits within an overall levelization design. Each package contributes one or more libraries, or an application that uses the other libraries. A package set is levelized if the relationships between packages form a directed, acyclic graph and each package uses only packages at lower levels of the diagram (in Fortran this relationship is often describable by the use relationship between modules). Independent packages permit independent- and therefore parallel|development. The packages form separable units for the purposes of development and testing. This is a proven path for enabling finer-grained changes to a complex code.
Induction technology optimization code
International Nuclear Information System (INIS)
Caporaso, G.J.; Brooks, A.L.; Kirbie, H.C.
1992-01-01
A code has been developed to evaluate relative costs of induction accelerator driver systems for relativistic klystrons. The code incorporates beam generation, transport and pulsed power system constraints to provide an integrated design tool. The code generates an injector/accelerator combination which satisfies the top level requirements and all system constraints once a small number of design choices have been specified (rise time of the injector voltage and aspect ratio of the ferrite induction cores, for example). The code calculates dimensions of accelerator mechanical assemblies and values of all electrical components. Cost factors for machined parts, raw materials and components are applied to yield a total system cost. These costs are then plotted as a function of the two design choices to enable selection of an optimum design based on various criteria. (Author) 11 refs., 3 figs
Vermont Center for Geographic Information — (Link to Metadata) A ZIP Code Tabulation Area (ZCTA) is a statistical geographic entity that approximates the delivery area for a U.S. Postal Service five-digit...
Anderson, John B
2017-01-01
Bandwidth Efficient Coding addresses the major challenge in communication engineering today: how to communicate more bits of information in the same radio spectrum. Energy and bandwidth are needed to transmit bits, and bandwidth affects capacity the most. Methods have been developed that are ten times as energy efficient at a given bandwidth consumption as simple methods. These employ signals with very complex patterns and are called "coding" solutions. The book begins with classical theory before introducing new techniques that combine older methods of error correction coding and radio transmission in order to create narrowband methods that are as efficient in both spectrum and energy as nature allows. Other topics covered include modulation techniques such as CPM, coded QAM and pulse design.
International Nuclear Information System (INIS)
Kulikowska, T.
2001-01-01
The description of reactor lattice codes is carried out on the example of the WIMSD-5B code. The WIMS code in its various version is the most recognised lattice code. It is used in all parts of the world for calculations of research and power reactors. The version WIMSD-5B is distributed free of charge by NEA Data Bank. The description of its main features given in the present lecture follows the aspects defined previously for lattice calculations in the lecture on Reactor Lattice Transport Calculations. The spatial models are described, and the approach to the energy treatment is given. Finally the specific algorithm applied in fuel depletion calculations is outlined. (author)
Critical Care Coding for Neurologists.
Nuwer, Marc R; Vespa, Paul M
2015-10-01
Accurate coding is an important function of neurologic practice. This contribution to Continuum is part of an ongoing series that presents helpful coding information along with examples related to the issue topic. Tips for diagnosis coding, Evaluation and Management coding, procedure coding, or a combination are presented, depending on which is most applicable to the subject area of the issue.
Natarajan, Lakshmi; Hong, Yi; Viterbo, Emanuele
2014-01-01
The index coding problem involves a sender with K messages to be transmitted across a broadcast channel, and a set of receivers each of which demands a subset of the K messages while having prior knowledge of a different subset as side information. We consider the specific case of noisy index coding where the broadcast channel is Gaussian and every receiver demands all the messages from the source. Instances of this communication problem arise in wireless relay networks, sensor networks, and ...
Towards advanced code simulators
International Nuclear Information System (INIS)
Scriven, A.H.
1990-01-01
The Central Electricity Generating Board (CEGB) uses advanced thermohydraulic codes extensively to support PWR safety analyses. A system has been developed to allow fully interactive execution of any code with graphical simulation of the operator desk and mimic display. The system operates in a virtual machine environment, with the thermohydraulic code executing in one virtual machine, communicating via interrupts with any number of other virtual machines each running other programs and graphics drivers. The driver code itself does not have to be modified from its normal batch form. Shortly following the release of RELAP5 MOD1 in IBM compatible form in 1983, this code was used as the driver for this system. When RELAP5 MOD2 became available, it was adopted with no changes needed in the basic system. Overall the system has been used for some 5 years for the analysis of LOBI tests, full scale plant studies and for simple what-if studies. For gaining rapid understanding of system dependencies it has proved invaluable. The graphical mimic system, being independent of the driver code, has also been used with other codes to study core rewetting, to replay results obtained from batch jobs on a CRAY2 computer system and to display suitably processed experimental results from the LOBI facility to aid interpretation. For the above work real-time execution was not necessary. Current work now centers on implementing the RELAP 5 code on a true parallel architecture machine. Marconi Simulation have been contracted to investigate the feasibility of using upwards of 100 processors, each capable of a peak of 30 MIPS to run a highly detailed RELAP5 model in real time, complete with specially written 3D core neutronics and balance of plant models. This paper describes the experience of using RELAP5 as an analyzer/simulator, and outlines the proposed methods and problems associated with parallel execution of RELAP5
DEFF Research Database (Denmark)
Rennison, Betina Wolfgang
2016-01-01
extensive work to raise the proportion of women. This has helped slightly, but women remain underrepresented at the corporate top. Why is this so? What can be done to solve it? This article presents five different types of answers relating to five discursive codes: nature, talent, business, exclusion...... in leadership management, we must become more aware and take advantage of this complexity. We must crack the codes in order to crack the curve....
Energy Technology Data Exchange (ETDEWEB)
Schultz, Peter Andrew
2011-12-01
The objective of the U.S. Department of Energy Office of Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC) is to provide an integrated suite of computational modeling and simulation (M&S) capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive-waste storage facility or disposal repository. Achieving the objective of modeling the performance of a disposal scenario requires describing processes involved in waste form degradation and radionuclide release at the subcontinuum scale, beginning with mechanistic descriptions of chemical reactions and chemical kinetics at the atomic scale, and upscaling into effective, validated constitutive models for input to high-fidelity continuum scale codes for coupled multiphysics simulations of release and transport. Verification and validation (V&V) is required throughout the system to establish evidence-based metrics for the level of confidence in M&S codes and capabilities, including at the subcontiunuum scale and the constitutive models they inform or generate. This Report outlines the nature of the V&V challenge at the subcontinuum scale, an approach to incorporate V&V concepts into subcontinuum scale modeling and simulation (M&S), and a plan to incrementally incorporate effective V&V into subcontinuum scale M&S destined for use in the NEAMS Waste IPSC work flow to meet requirements of quantitative confidence in the constitutive models informed by subcontinuum scale phenomena.
International Nuclear Information System (INIS)
Schultz, Peter Andrew
2011-01-01
The objective of the U.S. Department of Energy Office of Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC) is to provide an integrated suite of computational modeling and simulation (M and S) capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive-waste storage facility or disposal repository. Achieving the objective of modeling the performance of a disposal scenario requires describing processes involved in waste form degradation and radionuclide release at the subcontinuum scale, beginning with mechanistic descriptions of chemical reactions and chemical kinetics at the atomic scale, and upscaling into effective, validated constitutive models for input to high-fidelity continuum scale codes for coupled multiphysics simulations of release and transport. Verification and validation (V and V) is required throughout the system to establish evidence-based metrics for the level of confidence in M and S codes and capabilities, including at the subcontiunuum scale and the constitutive models they inform or generate. This Report outlines the nature of the V and V challenge at the subcontinuum scale, an approach to incorporate V and V concepts into subcontinuum scale modeling and simulation (M and S), and a plan to incrementally incorporate effective V and V into subcontinuum scale M and S destined for use in the NEAMS Waste IPSC work flow to meet requirements of quantitative confidence in the constitutive models informed by subcontinuum scale phenomena.