3-D neutron transport benchmarks
A set of 3-D neutron transport benchmark problems proposed by the Osaka University to NEACRP in 1988 has been calculated by many participants and the corresponding results are summarized in this report. The results of Keff, control rod worth and region-averaged fluxes for the four proposed core models, calculated by using various 3-D transport codes are compared and discussed. The calculational methods used were: Monte Carlo, Discrete Ordinates (Sn), Spherical Harmonics (Pn), Nodal Transport and others. The solutions of the four core models are quite useful as benchmarks for checking the validity of 3-D neutron transport codes
MT3D was first developed by Chunmiao Zheng in 1990 at S.S. Papadopulos & Associates, Inc. with partial support from the U.S. Environmental Protection Agency (USEPA). Starting in 1990, MT3D was released as a pubic domain code from the USEPA. Commercial versions with enhanced capab...
Lam, M.Ph
2008-06-15
This PhD research was conducted as a collaboration between Laboratoire National d'Hydraulique et Environnement (LNHE) from EDF R and D and the Institut de Mecanique des Fluides de Toulouse (IMFT) in the frame of a CIFRE contract. This PhD thesis aims at providing LNHE a reliable numerical model to study the feasibility of a nuclear waste storage in deep geological structures. The main focus of the thesis is put on developing and implementing a Random Walk Particle Method (RWPM) to model contaminant transport in 3D heterogeneous and fractured porous media. In its first part, the report presents the Lagrangian particle tracking method used to model transport in heterogeneous media with a direct high resolution approach. The solute plume is discretized into concentration packets: particles. The model tracks each particle based on a time-explicit displacement algorithm according to an advective component and a diffusive random component. The method is implemented on a hydraulic model discretized on a 3D unstructured tetrahedral finite element mesh. We focus on techniques to overcome problems due to the discontinuous transport parameters and the unstructured mesh. First, we introduce an asynchronous time-stepping approach to deal with the numerical and overshoot errors that occur with conventional RWPM. Then, a filtering method is applied to smooth discontinuous transport parameters (pre-processing). Finally, once the particle displacements are computed, we propose several filtering and sampling methods to obtain concentrations from particle positions (post-processing). Applications of these methods are presented with cases of tracer advection-dispersion in homogeneous and heterogeneous media. For dense fracture networks, direct high resolution methods are very time consuming and need a lot of computational resources. So, as an alternative to the discrete approach, a dual-continuum representation is used, in the second part of the report, to describe the porous
3-D Whole-Core Transport Calculation with 3D/2D Rotational Plane Slicing Method
Use of the method of characteristics (MOC) is very popular due to its capability of heterogeneous geometry treatment and widely used for 2-D core calculation, but direct extension of MOC to 3-D core is not so attractive due to huge calculational cost. 2-D/1-D fusion method was very successful for 3-D calculation of current generation reactor types (highly heterogeneous in radial direction but piece-wise homogeneous in axial direction). In this paper, 2-D MOC concept is extended to 3-D core calculation with little modification of an existing 2-D MOC code. The key idea is to suppose 3-D geometry as a set of many 2-D planes like a phone-directory book. Dividing 3-D structure into a large number of 2-D planes and solving each plane with a simple 2-D SN transport method would give the solution of a 3-D structure. This method was developed independently at KAIST but it is found that this concept is similar with that of 'plane tracing' in the MCCG-3D code. The method developed was tested on the 3-D C5G7 OECD/NEA benchmark problem and compared with the 2-D/1-D fusion method. Results show that the proposed method is worth investigating further. A new approach to 3-D whole-core transport calculation is described and tested. By slicing 3-D structure along characteristic planes and solving each 2-D plane problem, we can get 3-D solution. The numerical test results indicate that the new method is comparable with the 2D/1D fusion method and outperforms other existing methods. But more fair comparison should be done in similar discretization level
Glasinović, Frane
2011-01-01
AutoCAD Map 3D prvenstveno je CAD alat s dodatnim mogućnostima za izradu GIS sustava. Čine ga skup alata koji omogućavaju jednostavniji rad do vrlo dinamične i interaktivne karte i to s već ugrađenim prostornim analizama. AutoCAD Map se oslanja na snagu CAD-a pri uređivanju podataka, što je ujedno i njegova najveća prednost u odnosu na ostale GIS programe na tržištu. Pripremanje podataka te njihova distribucija i vizualizacija u istoj aplikaciji čine ga idealnim izborom. Rad sa različitim izv...
Quantum transport through 3D Dirac materials
Bismuth and its alloys provide a paradigm to realize three dimensional materials whose low-energy effective theory is given by Dirac equation in 3+1 dimensions. We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer–Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM). We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances the 3DDM appears transparent to electrons hitting the 3DDM. We find that electrons hitting the metal-3DDM interface from metallic side can enter 3DDM in a reversed spin state as soon as their angle of incidence deviates from the direction perpendicular to interface. However the presence of a second interface completely cancels this effect
Quantum transport through 3D Dirac materials
Salehi, M. [Department of Physics, Sharif University of Technology, Tehran 11155-9161 (Iran, Islamic Republic of); Jafari, S.A., E-mail: jafari@physics.sharif.edu [Department of Physics, Sharif University of Technology, Tehran 11155-9161 (Iran, Islamic Republic of); Center of Excellence for Complex Systems and Condensed Matter (CSCM), Sharif University of Technology, Tehran 1458889694 (Iran, Islamic Republic of)
2015-08-15
Bismuth and its alloys provide a paradigm to realize three dimensional materials whose low-energy effective theory is given by Dirac equation in 3+1 dimensions. We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer–Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM). We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances the 3DDM appears transparent to electrons hitting the 3DDM. We find that electrons hitting the metal-3DDM interface from metallic side can enter 3DDM in a reversed spin state as soon as their angle of incidence deviates from the direction perpendicular to interface. However the presence of a second interface completely cancels this effect.
Quantum transport through 3D Dirac materials
Salehi, M.; Jafari, S. A.
2015-08-01
Bismuth and its alloys provide a paradigm to realize three dimensional materials whose low-energy effective theory is given by Dirac equation in 3+1 dimensions. We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer-Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM). We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances the 3DDM appears transparent to electrons hitting the 3DDM. We find that electrons hitting the metal-3DDM interface from metallic side can enter 3DDM in a reversed spin state as soon as their angle of incidence deviates from the direction perpendicular to interface. However the presence of a second interface completely cancels this effect.
Heterogeneous 3-D SN transport reactor calculations using Attila
The Canadian Nuclear Safety Commission (CNSC) is preparing to license diverse reactor technologies (CANDU, LWR, small/research reactors). To this end, the CNSC has acquired the Attila SN transport code to serve as an independent tool in licensing reactor design evaluation. In this paper, we are presenting 3-D large scale parallel benchmark calculations of a small PWR with MOX using Attila SN transport code and their comparison to MCNP Monte Carlo. Our benchmark is that of Nam Zin Cho et al transformed into a new 3-D hexagonal geometry heterogeneous benchmark. It provides an evaluation of Attila code in complex calculations of power reactor core with MOX. In this benchmark, we computed using Attila the keff of the core with Control Rods and generated the assembly and pin powers choosing the pins placed in strong transport boundary layer effect zones. As a reference solution, the Monte Carlo MCNP calculations were obtained. The results show that the full core parallel heterogeneous 3-D SN transport calculations of a power reactor are feasible on a small workstation. Our keff results are within 0.8% (800 pcm) relative difference to MCNP reference result (0.9919) and assembly and pin power results are on the average about 2% and 3.6% different. These results validate the Attila code for nuclear design and licensing work. (author)
NOTRAN/3D, 3-D Neutron Transport in X-Y-Z Geometry by Discrete Nodal Transport Method
1 - Description of program or function: NOTRAN/3D solves the neutron transport equation in three-dimensional XYZ geometry by the discrete nodal transport method. Source and eigenvalue problems can be solved. The input format for cross sections is the same as for ANISN. Multigroup cross section libraries such as DLC-37 and DLC75/BUGLE-80 can be used. 2 - Method of solution: NOTRAN/3D uses the discrete nodal transport method. Anisotropic scattering is treated using Legendre expansion. The order of interior flux approximation is two. Plane or linear leakage approximation of surface flux is used. 3 - Restrictions on the complexity of the problem: Maximum order of: anisotropic scattering = 3; material compositions = 20; energy groups = 2; angular quadrature = 8; zones = 20. When coarse-mesh re-balancing is used, the maximum number of course meshes is 5 in each direction. If computer memory permits, some arrays can be enlarged to reduce the above restrictions
3D edge energy transport in stellarator configurations
McTaggart, N. [Max-Planck-Institut fuer Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, Wendelsteinstrasse 1, D-17491 Greifswald (Germany); Zagorski, R. [Institute of Plasma Physics and Laser Microfusion, P.O. Box 49, Warsaw (Poland)]. E-mail: zagorski@ifpilm.waw.pl; Bonnin, X. [Max-Planck-Institut fuer Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, Wendelsteinstrasse 1, D-17491 Greifswald (Germany); Runov, A. [Max-Planck-Institut fuer Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, Wendelsteinstrasse 1, D-17491 Greifswald (Germany); Schneider, R. [Max-Planck-Institut fuer Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, Wendelsteinstrasse 1, D-17491 Greifswald (Germany); Kaiser, T. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Rognlien, T. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Umansky, M. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)
2005-03-01
The finite difference discretization method is used to solve the electron energy transport equation in complex 3D edge geometries using an unstructured grid. This grid is generated by field-line tracing to separate the radial and parallel fluxes and minimize the numerical diffusion connected with the strong anisotropy of the system. The influence of ergodicity on the edge plasma transport in the W7-X stellarator is investigated in this paper. Results show that the combined effect of ergodicity and the radial plasma diffusion leads to the efficient smoothing of the temperature profiles in the finite-{beta} case.
Challenges in Lagrangian transport and predictability in 3D flows
Branicki, M.; Wiggins, S.; Kirwan, A. D.; Malek-Madani, R.
2011-12-01
The interplay between the geometrical theory of dynamical systems and the trajectory-based description of aperiodically time-dependent fluid flows has led to significant advances in understanding the role of chaotic transport in geophysical flows at scales dominated by advection. Lagrangian transport analysis utilizing either the time-dependent geometry of intersecting stable and unstable manifolds of the so-called Distinguished Hyperbolic Trajectories (DHT), or ridges of finite-time Lyapunov exponent fields (LCS), provide a much needed and complementary insight into ephemeral mechanisms responsible for the existence of `leaky' transport barriers and 'leaky' mesoscale eddies. However, to date most oceanic applications have been confined to 2D analysis of near surface regions in 'perfect' flows not accounting for model or measurement error, and with the tacit assumption of negligible vertical velocities. I will systematically address issues concerning the regimes of applicability of two-dimensional analysis in 3D aperiodically time-dependent flows, as well as outstanding challenges in fully 3D Lagrangian transport analysis. Even for perfect horizontal velocities, little is known about the vertical extent of stable/unstable manifolds associated with DHTs and/or other special structures relevant to stratified 3D flows. In particular, their sensitivity to errors in the vertical velocities and data assimilation methods has been little studied. Rigorous results regarding the above issues will be illustrated by revealing and mathematically tractable toy models, as well as examples from a detailed study in an eddy-rich region from the Gulf of Mexico and the Mediterranean. New ways of quantifying the uncertainty in Lagrangian predictions will also be presented.
Solute transport benchmark studies for TRACR3D code verification
A three-dimensional code called TRACR3D, which is applicable to solute transport in both unsaturated and saturated media, is being used to model hypothetical transport of radioactive and nonradioactive constituents from calcined high-level radioactive waste (HLW) at the Idaho Chemical Processing Plant (ICPP). The modeling studies are part of a documentation process which will be required for evaluation of onsite disposal in a near-surface facility as a possible alternative strategy for the long-term management of ICPP HLW. This report discusses the results of a benchmark study for code verification. The problems modeled were: (1) A one-dimensional problem involving the transport of the pertechnetate ion (TcO4-) through a 5-cm diameter by 30-cm-long soil column at ICPP. (2) A one-dimensional problem involving the transport of the iodide ion (I-) through a large caisson (3-m diameter by 6-m depth) at LANL. (3) A three-dimensional problem involving the transport of radioactive ruthenium (Ru-106) from a single-shell tank leak into the vadose zone at the Hanford site. For the three benchmark studies performed, it was concluded that the predicted results from TRACR3D were in agreement with documented and reported solute transport problems, that the input data files were properly configured, and that the code correctly performed the mathematical operations specified in the numerical models. These results will provide a greater degree of confidence in results obtained for planned modeling studies at ICPP. 6 refs., 8 figs., 2 tabs
Radiation Transport in 3D Heterogeneous Materials: DNS
In order to develop a phenomenological approach to transport in 3D heterogeneous media, we have performed direct numerical simulation studies. Using an algorithm based on the lattice random walk to generate random media, we have performed radiographic shots of the sample and digitized both the chord length and optical depth distributions. The optical depth distribution is then used to compute an effective mean free path. As theory predicts, the atomically averaged mean free path is always a minimum value. We have also demonstrated a dependency of mean free path on the distribution of random material
Transport of 3D space charge dominated beams
In this paper we present the theoretical analysis and the computer code design for the intense pulsed beam transport. Intense beam dynamics is a very important issue in low-energy high-current accelerators and beam transport systems. This problem affects beam transmission and beam qualities. Therefore, it attracts the attention of the accelerator physicists worldwide. The analysis and calculation for the intense beam dynamics are very complicated, because the state of particle motion is dominated not only by the applied electromagnetic fields, but also by the beam-induced electromagnetic fields (self-fields). Moreover, the self-fields are related to the beam dimensions and particle distributions. So, it is very difficult to get the self-consistent solutions of particle motion analytically. For this reason, we combine the Lie algebraic method and the particle in cell (PIC) scheme together to simulate intense 3D beam transport. With the Lie algebraic method we analyze the particle nonlinear trajectories in the applied electromagnetic fields up to third order approximation, and with the PIC algorithm we calculate the space charge effects to the particle motion. Based on the theoretical analysis, we have developed a computer code, which calculates beam transport systems consisting of electrostatic lenses, electrostatic accelerating columns, solenoid lenses, magnetic and electric quadruples, magnetic sextupoles, octopuses and different kinds of electromagnetic analyzers. The optimization calculations and the graphic display for the calculated results are provided by the code. (authors)
Membrane transport mechanism 3D structure and beyond
Ziegler, Christine
2014-01-01
This book provides a molecular view of membrane transport by means of numerous biochemical and biophysical techniques. The rapidly growing number of atomic structures of transporters in different conformations and the constant progress in bioinformatics have recently added deeper insights. The unifying mechanism of energized solute transport across membranes is assumed to consist of the conformational cycling of a carrier protein to provide access to substrate binding sites from either side of a cellular membrane. Due to the central role of active membrane transport there is considerable interest in deciphering the principles of one of the most fundamental processes in nature: the alternating access mechanism. This book brings together particularly significant structure-function studies on a variety of carrier systems from different transporter families: Glutamate symporters, LeuT-like fold transporters, MFS transporters and SMR (RND) exporters, as well as ABC-type importers. The selected examples im...
3D unstructured-mesh radiation transport codes
Morel, J. [Los Alamos National Lab., NM (United States)
1997-12-31
Three unstructured-mesh radiation transport codes are currently being developed at Los Alamos National Laboratory. The first code is ATTILA, which uses an unstructured tetrahedral mesh in conjunction with standard Sn (discrete-ordinates) angular discretization, standard multigroup energy discretization, and linear-discontinuous spatial differencing. ATTILA solves the standard first-order form of the transport equation using source iteration in conjunction with diffusion-synthetic acceleration of the within-group source iterations. DANTE is designed to run primarily on workstations. The second code is DANTE, which uses a hybrid finite-element mesh consisting of arbitrary combinations of hexahedra, wedges, pyramids, and tetrahedra. DANTE solves several second-order self-adjoint forms of the transport equation including the even-parity equation, the odd-parity equation, and a new equation called the self-adjoint angular flux equation. DANTE also offers three angular discretization options: $S{_}n$ (discrete-ordinates), $P{_}n$ (spherical harmonics), and $SP{_}n$ (simplified spherical harmonics). DANTE is designed to run primarily on massively parallel message-passing machines, such as the ASCI-Blue machines at LANL and LLNL. The third code is PERICLES, which uses the same hybrid finite-element mesh as DANTE, but solves the standard first-order form of the transport equation rather than a second-order self-adjoint form. DANTE uses a standard $S{_}n$ discretization in angle in conjunction with trilinear-discontinuous spatial differencing, and diffusion-synthetic acceleration of the within-group source iterations. PERICLES was initially designed to run on workstations, but a version for massively parallel message-passing machines will be built. The three codes will be described in detail and computational results will be presented.
Corradini, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Merucci, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Folch, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia
2011-01-01
The moderate Resolution Imaging Spectroradiometer (MODIS) is a multispectral satellite instrument operating from the visible to thermal infrared spectral range. FALL3D is a 3-D time-dependent Eulerian model for the transport and deposition of volcanic particles. In this letter, quantitative comparison between the volcanic cloud ash mass and optical depth retrieved by MODIS and modeled by FALL3D has been performed. Three MODIS images collected on October 28, 29, and 30 on Mt. Etna volcano duri...
Development of integrated transport code, TASK3D, and its applications to LHD experiment
The integrated transport code for helical plasmas, TASK3D, has been developed both by modifying modules in TASK to be applicable to three-dimensional magnetic configurations, and by adding new modules for stellarator-heliotron specific physics and incorporating three-dimensional equilibria. In this paper, these module developments so far are collectively introduced, and recent progress on the applications of TASK3D to heat transport analyses of LHD plasmas is introduced. (author)
Predicting longshore gradients in longshore transport: the CERC formula compared to Delft3D
List, Jeffrey H.; Hanes, Daniel M.; Ruggiero, Peter
2007-01-01
The prediction of longshore transport gradients is critical for forecasting shoreline change. We employ simple test cases consisting of shoreface pits at varying distances from the shoreline to compare the longshore transport gradients predicted by the CERC formula against results derived from the process-based model Delft3D. Results show that while in some cases the two approaches give very similar results, in many cases the results diverge greatly. Although neither approach is validated with field data here, the Delft3D-based transport gradients provide much more consistent predictions of erosional and accretionary zones as the pit location varies across the shoreface.
Bailey, Ryan T; Morway, Eric D; Niswonger, Richard G; Gates, Timothy K
2013-01-01
A numerical model was developed that is capable of simulating multispecies reactive solute transport in variably saturated porous media. This model consists of a modified version of the reactive transport model RT3D (Reactive Transport in 3 Dimensions) that is linked to the Unsaturated-Zone Flow (UZF1) package and MODFLOW. Referred to as UZF-RT3D, the model is tested against published analytical benchmarks as well as other published contaminant transport models, including HYDRUS-1D, VS2DT, and SUTRA, and the coupled flow and transport modeling system of CATHY and TRAN3D. Comparisons in one-dimensional, two-dimensional, and three-dimensional variably saturated systems are explored. While several test cases are included to verify the correct implementation of variably saturated transport in UZF-RT3D, other cases are included to demonstrate the usefulness of the code in terms of model run-time and handling the reaction kinetics of multiple interacting species in variably saturated subsurface systems. As UZF1 relies on a kinematic-wave approximation for unsaturated flow that neglects the diffusive terms in Richards equation, UZF-RT3D can be used for large-scale aquifer systems for which the UZF1 formulation is reasonable, that is, capillary-pressure gradients can be neglected and soil parameters can be treated as homogeneous. Decreased model run-time and the ability to include site-specific chemical species and chemical reactions make UZF-RT3D an attractive model for efficient simulation of multispecies reactive transport in variably saturated large-scale subsurface systems. PMID:23131109
Bailey, Ryan T.; Morway, Eric D.; Niswonger, Richard G.; Gates, Timothy K.
2013-01-01
A numerical model was developed that is capable of simulating multispecies reactive solute transport in variably saturated porous media. This model consists of a modified version of the reactive transport model RT3D (Reactive Transport in 3 Dimensions) that is linked to the Unsaturated-Zone Flow (UZF1) package and MODFLOW. Referred to as UZF-RT3D, the model is tested against published analytical benchmarks as well as other published contaminant transport models, including HYDRUS-1D, VS2DT, and SUTRA, and the coupled flow and transport modeling system of CATHY and TRAN3D. Comparisons in one-dimensional, two-dimensional, and three-dimensional variably saturated systems are explored. While several test cases are included to verify the correct implementation of variably saturated transport in UZF-RT3D, other cases are included to demonstrate the usefulness of the code in terms of model run-time and handling the reaction kinetics of multiple interacting species in variably saturated subsurface systems. As UZF1 relies on a kinematic-wave approximation for unsaturated flow that neglects the diffusive terms in Richards equation, UZF-RT3D can be used for large-scale aquifer systems for which the UZF1 formulation is reasonable, that is, capillary-pressure gradients can be neglected and soil parameters can be treated as homogeneous. Decreased model run-time and the ability to include site-specific chemical species and chemical reactions make UZF-RT3D an attractive model for efficient simulation of multispecies reactive transport in variably saturated large-scale subsurface systems.
Comprehensive safety studies of high temperature gas cooled reactors (HTR) require full three dimensional coupled treatments of both neutron kinetics and thermal-hydraulics. In a common effort, GRS and IKE developed the coupled code system TORT-TD/ATTICA3D for pebble bed type HTR that connects the 3-D transient discrete-ordinates transport code TORT-TD with the 3-D porous medium thermal-hydraulics code ATTICA3D. In this paper, the physical models and calculation capabilities of TORT-TD and ATTICA3D are presented, focusing on model improvements in ATTICA3D and extensions made in TORT-TD related to HTR application. For first applications, the OECD/NEA/NSC PBMR-400 benchmark has been chosen. Results obtained with TORT-TD/ATTICA3D will be shown for transient exercises, e.g. control rod withdrawal and a control rod ejection. Results are compared to other benchmark participants' solutions with special focus on fuel temperature modelling features of ATTICA3D. The provided “grey-curtain” nuclear cross section libraries have been used. First results on 3-D effects during a control rod withdrawal transient will be presented. (author)
2D/1D approximations to the 3D neutron transport equation. I: Theory
A new class of '2D/1D' approximations is proposed for the 3D linear Boltzmann equation. These approximate equations preserve the exact transport physics in the radial directions x and y and diffusion physics in the axial direction z. Thus, the 2D/1D equations are more accurate approximations of the 3D Boltzmann equation than the conventional 3D diffusion equation. The 2D/1D equations can be systematically discretized, to yield accurate simulation methods for 3D reactor core problems. The resulting solutions will be more accurate than 3D diffusion solutions, and less expensive to generate than standard 3D transport solutions. In this paper, we (i) show that the simplest 2D/1D equation has certain desirable properties, (ii) systematically discretize this equation, and (iii) derive a stable iteration scheme for solving the discrete system of equations. In a companion paper [1], we give numerical results that confirm the theoretical predictions of accuracy and iterative stability. (authors)
DANTSYS/MPI- a system for 3-D deterministic transport on parallel architectures
A data parallel version of the 3-D transport solver in DANTSYS has been in use on the SIMD CM-200s at LANL since 1994. This version typically obtains grind times of 150-200 nanoseconds on a 2048 PE CM-200. A new message passing parallel version of DANTSYS has been implemented referred to as DANTSYS/MPI, on the 512 PE Cray T3D at Los Alamos. By taking advantage of the SPMD architecture of the Cray T3D, as well as its low latency communications network, we have managed to achieve grind times of less than 10 nanoseconds on real problems. DANTSYS/MPI is fully accelerated using DSA on both the inner and outer iterations. The implementation is described of DANTSYS/MPI on the Cray T3D, and presents a simple performance model which accurately predicts the grind time as a function of the number of PE's and problem size, or scalableness. (author)
How Do Hydrodynamic Instabilities Affect 3D Transport in Geophysical Vortices?
Wang, P.; Ozgokmen, T. M.
2014-12-01
Understanding three-dimensional (3D) transport in ocean eddies is important for processes at a variety of scales, ranging from plankton production to climate variability. It is well known that geophysical vortices are subject to various hydrodynamic instabilities. Yet the influence of these instabilities on 3D material transport in vortex systems is not well investigated. Focusing on barotropic, inertial and 3D instabilities, we analyze these instabilities with normal-mode method, and reproduce their characteristics via highly-resolved numerical simulations using a spectral element Navier-Stokes solver. By comparing the simulation results of stable and unstable vortices, we investigate the joint impacts of instabilities on 3D transport through three major aspects: (i) energy transfer, (ii) overturning transport of the secondary circulation, and (iii) rates of vertical exchange and mixing. It is found that instabilities can enhance local nonlinear interactions and cause the kinetic energy wavenumber spectrum to have slopes between the conventional -5/3 and -3 at inertial ranges. The cascade of a new quantity is proposed to explain these non-conventional slopes. One of our main results is the discovery of material exchange between the central vortex and satellite vortices through 3D pathways, called funnels. These funnels modify the concept of elliptic regions that can trap material when confined to 2D dynamics. Thus, we show that a family of vortices, created by the hydrodynamic instabilities of the initially unstable vortex, can still continue to operate in unity in order to complete the 3D transport in these systems. We also show that flow instabilities can double the magnitude of vertical velocity, increase the rate of vertical exchange by an order of magnitude and enhance mixing rate more than 100%.
Development of a 3D neutron transport code and benchmark tests
Results are reported of NEACRP '3D Neutron Transport Benchmarks' proposed from Osaka UNiversity, and of recent progress in the development of a 3D neutron transport code. Takeda et al. proposed four problems to NEACRP as 3D neutron transport benchmarks, and 22 results from 20 organizations were submitted. A variety of methods have been used, such as the Monte Carlo, Sn, Pn, synthetic, and nodal method. The results for k-eff, control-rod worths, and region-averaged fluxes are summarized with the conclusions that (1) in XYZ geometry the Sn method with n=8 shows a good agreement with the Monte-Carlo method, and gives even better results in some cases, (2) the Pn method has significant spatial mesh effects, and (3) the Sn method is not satisfactory in hexagonal-Z geometry, and improvements in accuracy are desirable. Improvement of a 3D neutron transport code is in progress to resolve the problem in the hexagonal-Z geometry by considering new diamond difference schemes and an improved coarse-mesh method, and also by applying the nodal method. (author)
A 3D multigroup transport kinetics code in hexagonal geometry for fast reactor transient analysis
A description of the 3D multigroup diffusion/transport kinetics code HEXNODYN is given and numerical results are reported. HEXNODYN couples time integration by the quasi-static method with space integration by HEXNOD's analytic (diffusion option) or discrete ordinates (transport option) nodal method. An equivalent hexagonal version of the KfK rod ejection problem has been set up to validate the diffusion option by comparison with available 2D diffusion codes. The transport option has been validated by comparison with the diffusion option. Numerical results indicate that the diffusion option may be considered as fully validated while the transport version is at least internally consistent
PHT3D-UZF: A Reactive Transport Model for Variably-Saturated Porous Media.
Wu, Ming Zhi; Post, Vincent E A; Salmon, S Ursula; Morway, Eric D; Prommer, Henning
2016-01-01
A modified version of the MODFLOW/MT3DMS-based reactive transport model PHT3D was developed to extend current reactive transport capabilities to the variably-saturated component of the subsurface system and incorporate diffusive reactive transport of gaseous species. Referred to as PHT3D-UZF, this code incorporates flux terms calculated by MODFLOW's unsaturated-zone flow (UZF1) package. A volume-averaged approach similar to the method used in UZF-MT3DMS was adopted. The PHREEQC-based computation of chemical processes within PHT3D-UZF in combination with the analytical solution method of UZF1 allows for comprehensive reactive transport investigations (i.e., biogeochemical transformations) that jointly involve saturated and unsaturated zone processes. Intended for regional-scale applications, UZF1 simulates downward-only flux within the unsaturated zone. The model was tested by comparing simulation results with those of existing numerical models. The comparison was performed for several benchmark problems that cover a range of important hydrological and reactive transport processes. A 2D simulation scenario was defined to illustrate the geochemical evolution following dewatering in a sandy acid sulfate soil environment. Other potential applications include the simulation of biogeochemical processes in variably-saturated systems that track the transport and fate of agricultural pollutants, nutrients, natural and xenobiotic organic compounds and micropollutants such as pharmaceuticals, as well as the evolution of isotope patterns. PMID:25628017
PHT3D-UZF: A reactive transport model for variably-saturated porous media
Wu, Ming Zhi; Post, Vincent E. A.; Salmon, S. Ursula; Morway, Eric; Prommer, H.
2016-01-01
A modified version of the MODFLOW/MT3DMS-based reactive transport model PHT3D was developed to extend current reactive transport capabilities to the variably-saturated component of the subsurface system and incorporate diffusive reactive transport of gaseous species. Referred to as PHT3D-UZF, this code incorporates flux terms calculated by MODFLOW's unsaturated-zone flow (UZF1) package. A volume-averaged approach similar to the method used in UZF-MT3DMS was adopted. The PHREEQC-based computation of chemical processes within PHT3D-UZF in combination with the analytical solution method of UZF1 allows for comprehensive reactive transport investigations (i.e., biogeochemical transformations) that jointly involve saturated and unsaturated zone processes. Intended for regional-scale applications, UZF1 simulates downward-only flux within the unsaturated zone. The model was tested by comparing simulation results with those of existing numerical models. The comparison was performed for several benchmark problems that cover a range of important hydrological and reactive transport processes. A 2D simulation scenario was defined to illustrate the geochemical evolution following dewatering in a sandy acid sulfate soil environment. Other potential applications include the simulation of biogeochemical processes in variably-saturated systems that track the transport and fate of agricultural pollutants, nutrients, natural and xenobiotic organic compounds and micropollutants such as pharmaceuticals, as well as the evolution of isotope patterns.
Benchmark of the 3-dimensional plasma transport codes E3D and BoRiS
The next generation of experiments - both for tokamaks and stellarators - require the development of appropriate theoretical models. One important aspect here is the plasma edge physics description. Fluid transport codes extending beyond the standard 2-D code packages like B2-Eirene or UEDGE are under development. In the case of tokamaks, an interesting alternative line is the concept of an ergodic edge (necessary e.g. for ergodic divertors in TORE SUPRA or TEXTOR-94) creating a 3-D edge structure. To study this effects, a 3-D code E3D based upon Multiple Coordinate Systems Approach is being developed. Presently, we extend the program towards stellarator applications. A few new options are made available: single-island geometry and new formulation of boundary conditions. For the new stellarator W7-X a 3-D finite volume code BoRiS is developed using magnetic (Boozer) coordinates. In this paper, we present a benchmark of both codes for a test geometry (single magnetic island in W7-X) accounting for full 3-D metric variations for strongly anisotropic electron heat conduction equation. (orig.)
Advanced quadratures and periodic boundary conditions in parallel 3D S{sub n} transport
Manalo, K.; Yi, C.; Huang, M.; Sjoden, G. [Nuclear and Radiological Engineering Program, G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 770 State Street, Atlanta, GA 30332-0745 (United States)
2013-07-01
Significant updates in numerical quadratures have warranted investigation with 3D Sn discrete ordinates transport. We show new applications of quadrature departing from level symmetric (S{sub 2}o). investigating 3 recently developed quadratures: Even-Odd (EO), Linear-Discontinuous Finite Element - Surface Area (LDFE-SA), and the non-symmetric Icosahedral Quadrature (IC). We discuss implementation changes to 3D Sn codes (applied to Hybrid MOC-Sn TITAN and 3D parallel PENTRAN) that can be performed to accommodate Icosahedral Quadrature, as this quadrature is not 90-degree rotation invariant. In particular, as demonstrated using PENTRAN, the properties of Icosahedral Quadrature are suitable for trivial application using periodic BCs versus that of reflective BCs. In addition to implementing periodic BCs for 3D Sn PENTRAN, we implemented a technique termed 'angular re-sweep' which properly conditions periodic BCs for outer eigenvalue iterative loop convergence. As demonstrated by two simple transport problems (3-group fixed source and 3-group reflected/periodic eigenvalue pin cell), we remark that all of the quadratures we investigated are generally superior to level symmetric quadrature, with Icosahedral Quadrature performing the most efficiently for problems tested. (authors)
The interplay of sunlight with clouds is a ubiquitous and often pleasant visual experience, but it conjures up major challenges for weather, climate, environmental science and beyond. Those engaged in the characterization of clouds (and the clear air nearby) by remote sensing methods are even more confronted. The problem comes, on the one hand, from the spatial complexity of real clouds and, on the other hand, from the dominance of multiple scattering in the radiation transport. The former ingredient contrasts sharply with the still popular representation of clouds as homogeneous plane-parallel slabs for the purposes of radiative transfer computations. In typical cloud scenes the opposite asymptotic transport regimes of diffusion and ballistic propagation coexist. We survey the three-dimensional (3D) atmospheric radiative transfer literature over the past 50 years and identify three concurrent and intertwining thrusts: first, how to assess the damage (bias) caused by 3D effects in the operational 1D radiative transfer models? Second, how to mitigate this damage? Finally, can we exploit 3D radiative transfer phenomena to innovate observation methods and technologies? We quickly realize that the smallest scale resolved computationally or observationally may be artificial but is nonetheless a key quantity that separates the 3D radiative transfer solutions into two broad and complementary classes: stochastic and deterministic. Both approaches draw on classic and contemporary statistical, mathematical and computational physics.
Research of 3-D hexagonal nodal transport method for fast reactor
The 3-D hexagonal nodal transport theory calculation method for fast reactor core was studied. Based on this method, 3-D hexagonal nodal transport code NAST was developed. The surface average angular fluxes were approximated by an azimuthally symmetric double Pn-expansion DP1 and DP3, and 1-D discrete ordinates equations were solved on a fine spatial mesh within the node. Considering the characteristics of the nodal method, the response matrix method was used in the iterations. Therefore, the calculation within the node was simplified and time was saved. The code was tested for the keff, calculation of CEFR and BN-600. A good agreement with the reference results was achieved. (authors)
2D/1D approximations to the 3D neutron transport equation. II: Numerical comparisons
In a companion paper [1], (i) several new '2D/1D equations' are introduced as accurate approximations to the 3D Boltzmann transport equation, (ii) the simplest of these approximate equations is systematically discretized, and (iii) a theoretically stable iteration scheme is developed to solve the discrete equations. In this paper, numerical results are presented that confirm the theoretical predictions made in [1]. (authors)
BioFVM: an efficient, parallelized diffusive transport solver for 3-D biological simulations
Ghaffarizadeh, Ahmadreza; Friedman, Samuel H.; Macklin, Paul
2015-01-01
Motivation: Computational models of multicellular systems require solving systems of PDEs for release, uptake, decay and diffusion of multiple substrates in 3D, particularly when incorporating the impact of drugs, growth substrates and signaling factors on cell receptors and subcellular systems biology. Results: We introduce BioFVM, a diffusive transport solver tailored to biological problems. BioFVM can simulate release and uptake of many substrates by cell and bulk sources, diffusion and de...
A 3D transport-based core analysis code for research reactors with unstructured geometry
Highlights: • A core analysis code package based on 3D neutron transport calculation in complex geometry is developed. • The fine considerations on flux mapping, control rod effects and isotope depletion are modeled. • The code is proved to be with high accuracy and capable of handling flexible operational cases for research reactors. - Abstract: As an effort to enhance the accuracy in simulating the operations of research reactors, a 3D transport core analysis code system named REFT was developed. HELIOS is employed due to the flexibility of describing complex geometry. A 3D triangular nodal SN method transport solver, DNTR, endows the package the capability of modeling cores with unstructured geometry assemblies. A series of dedicated methods were introduced to meet the requirements of research reactor simulations. Afterwards, to make it more user friendly, a graphical user interface was also developed for REFT. In order to validate the developed code system, the calculated results were compared with the experimental results. Both the numerical and experimental results are in close agreement with each other, with the relative errors of keff being less than 0.5%. Results for depletion calculations were also verified by comparing them with the experimental data and acceptable consistency was observed in results
DANTSYS/MPI: a system for 3-D deterministic transport on parallel architectures
Baker, R.S.; Alcouffe, R.E.
1996-12-31
Since 1994, we have been using a data parallel form of our deterministic transport code DANTSYS to perform time-independent fixed source and eigenvalue calculations on the CM-200`s at Los Alamos National Laboratory (LANL). Parallelization of the transport sweep is obtained by using a 2-D spatial decomposition which retains the ability to invert the source iteration equation in a single iteration (i.e., the diagonal plane sweep). We have now implemented a message passing version of DANTSYS, referred to as DANTSYS/MPI, on the Cray T3D installed at Los Alamos in 1995. By taking advantage of the SPMD (Single Program, Multiple Data) architecture of the Cray T3D, as well as its low latency communications network, we have managed to achieve grind times (time to solve a single cell in phase space) of less than 10 nanoseconds on the 512 PE (Processing Element) T3D, as opposed to typical grind times of 150-200 nanoseconds on a 2048 PE CM-200, or 300-400 nanoseconds on a single PE of a Cray Y-MP. In addition, we have also parallelized the Diffusion Synthetic Accelerator (DSA) equations which are used to accelerate the convergence of the transport equation. DANTSYS/MPI currently runs on traditional Cray PVP`s and the Cray T3D, and it`s computational kernel (Sweep3D) has been ported to and tested on an array of SGI SMP`s (Symmetric Memory Processors), a network of IBM 590 workstations, an IBM SP2, and the Intel TFLOPs machine at Sandia National Laboratory. This paper describes the implementation of DANTSYS/MPI on the Cray T3D, and presents a simple performance model which accurately predicts the grind time as a function of the number of PE`s and problem size, or scalability. This paper also describes the parallel implementation and performance of the elliptic solver used in DANTSYS/MPI for solving the synthetic acceleration equations.
Radon transport modelling: User's guide to RnMod3d
Andersen, C.E
2000-08-01
RnMod3d is a numerical computer model of soil-gas and radon transport in porous media. It can be used, for example, to study radon entry from soil into houses in response to indoor-outdoor pressure differences or changes in atmospheric pressure. It can also be used for flux calculations of radon from the soil surface or to model radon exhalation from building materials such as concrete. The finite-volume model is a technical research tool, and it cannot be used meaningfully without good understanding of the involved physical equations. Some understanding of numerical mathematics and the programming language Pascal is also required. Originally, the code was developed for internal use at Risoe only. With this guide, however, it should be possible for others to use the model. Three-dimensional steady-state or transient problems with Darcy flow of soil gas and combined generation, radioactive decay, diffusion and advection of radon can be solved. Moisture is included in the model, and partitioning of radon between air, water and soil grains (adsorption) is taken into account. Most parameters can change in time and space, and transport parameters (diffusivity and permeability) may be anisotropic. This guide includes benchmark tests based on simple problems with known solutions. RnMod3d has also been part of an international model intercomparison exercise based on more complicated problems without known solutions. All tests show that RnMod3d gives results of good quality. (au)
Agent code: Neutron transport benchmark example and extension to 3D lattice geometry
Hursin Mathieu
2005-01-01
Full Text Available The general methodology be hind 2D arbitrary geometry neutron transport AGENT code is the theory of R-functions, which al lows for simple modeling of complex geometries, and the method of characteristics, which solves the integral transport equation along characteristic neutron trajectories. This paper focuses on the extension of the methodology to ac count for 3D lattice geometries. Since the direct application of method of characteristics to 3D non-homogenized core con figuration may re quire a tremendous amount of memory and computing time, an alternative approximate solution based on coupling 2D method of characteristics and 1D diffusion solution is developed. The planar 2D method of characteristics and axial 1D diffusion solutions are coupled through the trans verse leak age. The use of a lower order 1D solution in the axial direction is justified by the fact that more heterogeneity in current PWR and BWR reactor cores occurs in the radial direction than in the axial one. In order to demonstrate the versatility and accuracy of the AGENT code, a 2D heterogeneous lattice problem, C5G7 is described in details. A theoretical description of the coupling methodology for 3D method of characteristics solution is followed by preliminary validation in comparison to the DeCART code.
Radon transport modelling: User's guide to RnMod3d
RnMod3d is a numerical computer model of soil-gas and radon transport in porous media. It can be used, for example, to study radon entry from soil into houses in response to indoor-outdoor pressure differences or changes in atmospheric pressure. It can also be used for flux calculations of radon from the soil surface or to model radon exhalation from building materials such as concrete. The finite-volume model is a technical research tool, and it cannot be used meaningfully without good understanding of the involved physical equations. Some understanding of numerical mathematics and the programming language Pascal is also required. Originally, the code was developed for internal use at Risoe only. With this guide, however, it should be possible for others to use the model. Three-dimensional steady-state or transient problems with Darcy flow of soil gas and combined generation, radioactive decay, diffusion and advection of radon can be solved. Moisture is included in the model, and partitioning of radon between air, water and soil grains (adsorption) is taken into account. Most parameters can change in time and space, and transport parameters (diffusivity and permeability) may be anisotropic. This guide includes benchmark tests based on simple problems with known solutions. RnMod3d has also been part of an international model intercomparison exercise based on more complicated problems without known solutions. All tests show that RnMod3d gives results of good quality. (au)
Verification of 3D heterogeneous core transport calculation utilizing non-linear iteration technique
A three dimensional heterogeneous core transport analysis code CHAPLET-3D, which is based on deterministic methods, has been developed. In CHAPLET-3D code, the non-linear iteration technique, which is commonly used in advanced nodal diffusion codes, is employed to perform three dimensional heterogeneous core calculation in form of conventional finite difference method with the accuracy of the method of characteristics in radial two dimensional geometry. For an axial direction solver, in addition to finite difference method and nodal expansion method in diffusion theory, the method of characteristics has been incorporated in order to take account of transport effect. According to the verification tests compared with the results of multi-group Monte Carlo reference calculations, it is found that the accuracy of CHAPLET-3D code for three dimensional heterogeneous core analysis is almost the same level as that of the reference calculation and also demonstrated that the three dimensional core analysis method utilizing the non-linear iteration technique introduced here is valid and useful. (author)
Quasi 3D refined simulation of flow and pollutant transport in a meandering River Reach
Li-ren Yu
2013-03-01
Full Text Available This paper reports a quasi 3D numerical simulation in a meandering river reach of the Yellow River, aiming to develop a tool for modeling turbulent flows and pollutant transport in complex natural waters. The recently built depth-averaged two-equation turbulence model, together with and models, were used to close non-simplified quasi 3D hydrodynamic fundamental governing equations. The discretized equations were solved by advanced multi-grid iterative method under non-orthogonal body-fitted coarse and fine two-levels’ grids with collocated variable arrangement. Except for steady flow and transport computation, the processes of contaminant inpouring and plume development, caused by the side-discharge from a tribytary, also have been investigated numerically. The used three closure approaches are suitable for modeling strong mixing turbulence. The established model with higher order of magnitude of transported variable provides a possibility to elevate the computational precision. Based on the developed mathematical model, a CFD (Computational Fluid Dynamics software, namely Q3drm1.0, was developed. This numerical tool focuses on the refined simulations of the steady and unsteady problems of flow and temperature/contaminant transports in complicated computational domains with the strong ability to deal with different discharge situations: side-discharge, point-source discharge/point-sink, and area-source discharge from the slope along bank. In this article, the study of side-discharge is presented only.
Compresión y transporte de televisión 3D sobre redes IP
González Fernández, Sergio
2010-01-01
Este proyecto trata sobre la compresión y el transporte sobre redes IP de flujos de vídeo 3D (estereoscópicos). En lo que a la compresión se refiere, se han utilizado dos codificadores de vídeo multivista (MVC), que es un tipo específico de codificador que permite una alta compresión de flujos 3D, y los hemos analizado detenidamente y comparado mediante la realización de una serie de pruebas. Uno de los codificadores ha sido desarrollado por la empresa de telefonía móvil NOKIA y el otro por e...
Progress on CORSICA 3: Coupling 3D turbulence to 1D transport in tokamaks
Self-consistent quantitative modelling of surface-averaged radial profiles, which both drive and evolve under the influence of small-amplitude turbulence, is essential both for understanding transport in present tokamaks and for predicting the performance of future large machines. However, the large separation of transport and turbulence timescales makes straightforward running of 3D turbulence codes on the long, transport timescale prohibitively expensive. An efficient method for numerical solution of the scale-separated equations has been previously reported using the 2D Hasegawa-Wakatani equations as the turbulence model. Both local and global version shave been implemented; the latter correctly accounts for all nonlocal effects and achieves a significant CPU-savings
Quasi 3D modeling of water flow and solute transport in vadose zone and groundwater
Yakirevich, A.; Kuznetsov, M.; Weisbrod, N.; Pachepsky, Y. A.
2013-12-01
The complexity of subsurface flow systems calls for a variety of concepts leading to the multiplicity of simplified flow models. One commonly used simplification is based on the assumption that lateral flow and transport in unsaturated zone is insignificant unless the capillary fringe is involved. In such cases the flow and transport in the unsaturated zone above groundwater level can be simulated as a 1D phenomenon, whereas through groundwater they are viewed as 2D or 3D phenomena. A new approach for a numerical scheme for 3D variably saturated flow and transport is presented. A Quasi-3D approach allows representing flow in the 'vadose zone - aquifer' system by a series of 1D Richards' equations solved in variably-saturated zone and by 3D-saturated flow equation in groundwater (modified MODFLOW code). The 1D and 3D equations are coupled at the phreatic surface in a way that aquifer replenishment is calculated using the Richards' equation, and solving for the moving water table does not require definition of the specific yield parameter. The 3D advection-dispersion equation is solved in the entire domain by the MT3D code. Using implicit finite differences approximation to couple processes in the vadose zone and groundwater provides mass conservation and increase of computational efficiency. The above model was applied to simulate the impact of irrigation on groundwater salinity in the Alto Piura aquifer (Northern Peru). Studies on changing groundwater quality in arid and semi-arid lands show that irrigation return flow is one of the major factors contributing to aquifer salinization. Existing mathematical models do not account explicitly for the solute recycling during irrigation on a daily scale. Recycling occurs throughout the unsaturated and saturated zones, as function of the solute mass extracted from pumping wells. Salt concentration in irrigation water is calculated at each time step as a function of concentration of both surface water and groundwater
A 3D approach to equilibrium, stability and transport studies in RFX-mod improved regimes
Terranova, D; Bonfiglio, D; Gobbin, M; Lorenzini, R; Marrelli, L; Martines, E; Momo, B; Predebon, I; Spizzo, G; Agostini, M; Alfier, A; Apolloni, L; Auriemma, F; Baruzzo, M; Bolzonella, T [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Padova (Italy); Boozer, A H [Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY (United States); Cooper, A W [EPFL, Association EURATOM-Confederation Suisse, Centre de Recherches en Physique des Plasmas, Lausanne (Switzerland); Hirshman, S P; Sanchez, R [ORNL Fusion Energy Division, Oak Ridge, TN (United States); Pomphrey, N, E-mail: david.terranova@igi.cnr.i [Princeton Plasma Physics Laboratory, Princeton, NJ (United States)
2010-12-15
The full three-dimensional (3D) approach is now becoming an important issue for all magnetic confinement configurations. It is a necessary condition for the stellarator but also the tokamak and the reversed field pinch (RFP) now cannot be completely described in an axisymmetric framework. For the RFP the observation of self-sustained helical configurations with improved plasma performances require a better description in order to assess a new view on this configuration. In this new framework plasma configuration studies for RFX-mod have been considered both with tools developed for the RFP as well as considering codes originally developed for the stellarator and adapted to the RFP. These helical states are reached through a transition to a very low/reversed shear configuration leading to internal electron transport barriers. These states are interrupted by MHD reconnection events and the large T{sub e} gradients at the barriers indicate that both current and pressure driven modes are to be considered. Furthermore the typically flat T{sub e} profiles in the helical core have raised the issue of the role of electrostatic and electromagnetic turbulence in these reduced chaos regions, so that a stability analysis in the correct 3D geometry is required to address an optimization of the plasma setup. In this view the VMEC code proved to be an effective way to obtain helical equilibria to be studied in terms of stability and transport with a suite of well tested codes. In this work, the equilibrium reconstruction technique as well as the experimental evidence of 3D effects and their first interpretation in terms of stability and transport are presented using both RFP and stellarator tools.
Variational nodal method (VNM) to solve 3-D transport equation. Application to EFR design
The physics design of both thermal and fast reactors requires the capability to solve in an accurate manner the neutron transport equation in three dimensional geometry. As a typical example, the paper shows the application of the Variational Nodal Method (VNM) to EFR (European Fast Reactor) to study the detection of a Control Rod Withdrawal (CRW) fault. The VNM has been incorporated in the past by CEA in the ANL code DIF3D and, more recently, in the European system of codes ERANOS (TGV code). Numerical tests based on international benchmarks and calculations show the validity and the efficiency of the proposed VNM. (orig.)
3D mathematical model for suspended load transport by turbulent flows and its applications
LU Yongjun; DOU Guoren; HAN Longxi; SHAO Xuejun; YANG Xianghua
2004-01-01
This paper presents a 3D mathematical model for suspended load transport in turbulent flows. Based on Dou's stochastic theory of turbulent flow, numerical schemes of Reynolds stresses for anisotropic turbulent flows were obtained. A refined wall function was employed to treat solid wall boundaries. The equations for 2D suspended load motion and sorting of bed material have been expanded into 3D cases. Numerical results are validated by the measured data of the Gezhouba Project, and proved to be in good agreement with the experimental. The present method has been employed to simulate sediment erosion and deposition in the dam area of Three Gorges Project, and for the operation of the project, siltation process and deposition pattern in the near-dam area of the reservoir, size distribution of the deposits and bed material, and flow fields and sediment concentration fields at different time and elevations are predicted. The predicted results are close to the experimental observations in physical model studies. Thus, a new method is established for 3D simulation of sediment motion in dam areas of multi-purpose water projects.
Domain decomposition PN solutions to the 3D transport benchmark over a range in parameter space
The objectives of this contribution are twofold. First, the Domain Decomposition (DD) method used in the PARAFISH parallel transport solver is re-interpreted as a Generalized Schwarz Splitting as defined by Tang [SIAM J Sci Stat Comput, vol.13 (2), pp. 573-595, 1992]. Second, PARAFISH provides spherical harmonic (i.e., PN) solutions to the NEA benchmark suite for 3D transport methods and codes over a range in parameter space. To the best of the author's knowledge, these are the first spherical harmonic solutions provided for this demanding benchmark suite. They have been obtained using 512 CPU cores of the JuRoPa machine installed at the Juelich Computing Center (Germany). (author)
Ash3d: A finite-volume, conservative numerical model for ash transport and tephra deposition
Schwaiger, Hans F.; Denlinger, Roger P.; Mastin, Larry G.
2012-01-01
We develop a transient, 3-D Eulerian model (Ash3d) to predict airborne volcanic ash concentration and tephra deposition during volcanic eruptions. This model simulates downwind advection, turbulent diffusion, and settling of ash injected into the atmosphere by a volcanic eruption column. Ash advection is calculated using time-varying pre-existing wind data and a robust, high-order, finite-volume method. Our routine is mass-conservative and uses the coordinate system of the wind data, either a Cartesian system local to the volcano or a global spherical system for the Earth. Volcanic ash is specified with an arbitrary number of grain sizes, which affects the fall velocity, distribution and duration of transport. Above the source volcano, the vertical mass distribution with elevation is calculated using a Suzuki distribution for a given plume height, eruptive volume, and eruption duration. Multiple eruptions separated in time may be included in a single simulation. We test the model using analytical solutions for transport. Comparisons of the predicted and observed ash distributions for the 18 August 1992 eruption of Mt. Spurr in Alaska demonstrate to the efficacy and efficiency of the routine.
Toolbox for 3D imaging and modeling of porous media: Relationship with transport properties
Porous media can be considered as interfacial systems where an internal surface partitions and fills the space in a complex way. Meaningful structural features appear on a length-scale where physical chemistry plays a central role either to impose a specific organisation on the material or to strongly modify the dynamics and the thermodynamics of the embedded fluids. A key issue is to understand how the geometrical and interfacial confinement affects numerous phenomena such as molecular diffusion, excitation relaxation, reaction kinetics, phase transitions, adsorption and capillary condensation. We will first review some experimental techniques able to image the 3D structure of disordered porous media. In the second part, we will analyse the geometrical and particularly some topological properties of a disordered porous material. We will discuss the interest and the limits of several strategies for obtaining 3D representations of various pore networks starting from an incomplete set of morphological characterisations. Finally, connection between geometry and diffusive transport will be presented, with emphasis on the application of pulsed gradient spin echo NMR technique as a tool for a multiscale analysis of transport in a confining geometry
Validation of 3-D CFD Model of Tritium Transport in the Atmosphere
When solving 3-D problems for the atmospheric impurity transport in the bounded area, it is essential for the atmospheric dynamics to be correctly computed taking into account the actual terrain topography and environments specified by the boundary conditions. Such conditions as turbulence, convection, condensation and moisture evaporation processes, etc. are to be also taken into account as well as the interaction processes among impurities (gases, aerosols), atmosphere and the Earth's surface.3-D computational fluid dynamics model(CFD) developed on the basis of SRP hydrodynamic code was used to simulate tritium plume evolution and tritium transport in atmosphere under the area with relatively complex topography. SRP code is based on the continuum motion equations (Navier-Stockes equations) and thermodynamic relations taking into account specific features of atmospheric flows and complex topography and is designed to use on PC-type computers.The model has been validated using experimental release of tritium with specified source term and meteorology. Due to low release height above the underlying surface a fine grid was used in the vertical direction near the underlying surface. HT and HTO/H2O vertical fluxes were taken into account. Evolution of HT and HTO activities at 2 sampling locations along the plume axe were available for model-experiment inter-comparison. The modeling results of HT and HTO activities in the air during plume travel are in satisfactory agreement with observed values
3D numerical simulation of the transport of chemical signature compounds from buried landmines
Irrazabal, Maik; Borrero, Ernesto; Briano, Julio G.; Castro, Miguel; Hernandez, Samuel P.
2005-06-01
The transport of the chemical signature compounds from buried landmines in a three-dimensional (3D) array has been numerically modeled using the finite-volume technique. Compounds such as trinitrotoluene, dinitrotoluene, and their degradation products, are semi volatile and somewhat soluble in water. Furthermore, they can strongly adsorb to the soil and undergo chemical and biological degradation. Consequently, the spatial and temporal concentration distributions of such chemicals depend on the mobility of the water and gaseous phases, their molecular and mechanical diffusion, adsorption characteristics, soil water content, compaction, and environmental factors. A 3D framework is required since two-dimensional (2D) symmetry may easily fade due to terrain topography: non-flat surfaces, soil heterogeneity, or underground fractures. The spatial and temporal distribution of the chemical-signature-compounds, in an inclined grid has been obtained. The fact that the chemicals may migrate horizontally, giving higher surface concentrations at positions not directly on top of the objects, emphasizes the need for understanding the transport mechanism when a chemical detector is used. Deformation in the concentration contours after rainfall is observed in the inclined surface and is attributed to both: the advective flux, and to the water flux at the surface caused by the slope. The analysis of the displacements in the position of the maximum concentrations at the surface, respect to the actual location of the mine, in an inclined system, is presented.
1 - Description of program or function: DIF3D solves multigroup diffusion theory eigenvalue, adjoint, fixed source and criticality (concentration search) problems in 1-, 2- and 3-space dimensions for orthogonal (rectangular or cylindrical), triangular and hexagonal geometries. Anisotropic diffusion coefficients are permitted. Flux and power density maps by mesh cell and region-wise balance integrals are provided. Although primarily designed for fast reactor problems, up-scattering and internal black boundary conditions are also treated. The DIF3D8.0/VARIANT8.0 release differs from the previous DIF3D7.0 release in that it includes a significantly expanded set of solution techniques using variational nodal methods. DIF3D's nodal option solves the multigroup steady state neutron diffusion equation in two- and three-dimensional hexagonal and cartesian geometries and solves the transport equation in two-and three-dimensional cartesian geometries. Eigenvalue, adjoint, fixed source and criticality (concentration) search problems are permitted as are anisotropic diffusion coefficients. Flux and power density maps by mesh cell and region-wise balance integrals are provided. Although primarily designed for fast reactor problems, up-scattering and for finite difference option only internal black boundary conditions are also treated. VARIANT solves the multigroup steady-state neutron diffusion and transport equations in two- and three-dimensional Cartesian and hexagonal geometries using variational nodal methods. The transport approximations involve complete spherical harmonic expansions up to order P5. Eigenvalue, adjoint, fixed source, gamma heating, and criticality (concentration) search problems are permitted. Anisotropic scattering is treated, and although primarily designed for fast reactor problems, up-scattering options are also included. Related and Auxiliary Programs: DIF3D reads and writes the standard interface files specified by the Committee on Computer Code
Jompob WAEWSAK
2014-12-01
Full Text Available This paper presents a 3-D numerical modeling of heat transport phenomena in soil due to a change of sensible and latent heat, under the ambient conditions of southern Thailand. The vertical soil temperature profile within 3 m was predicted based on energy balance and 3 modes of heat transfer mechanisms, i.e., conduction, convection, and radiation. Mathematical models for estimation of solar radiation intensity, ambient and sky temperatures, relative humidity, and surface wind velocity were used as model inputs. 3-D numerical implicit finite difference schemes, i.e., forward time, and forward, center, and backward spaces were used for discretizing the set of governing, initial, and boundary condition equations. The set of pseudo-linear equations were then solved using the single step Gauss-Seidel iteration method. Computer code was developed by using MATLAB computer software. The soil physical effects; density, thermal conductivity, emissivity, absorptivity, and latent heat on amplitude of soil temperature variation were investigated. Numerical results were validated in comparison to the experimental results. It was found that 3-D numerical modeling could predict the soil temperature to almost the same degree as results that were obtained by experimentation, especially at a depth of 1 m. The root mean square error at ground surface and at depths of 0.5, 1, 1.5, 2, 2.5 and 3 m were 0.169, 0.153, 0.097, 0.116, 0.120, 0.115, and 0.098, respectively. Furthermore, it was found that variation of soil temperature occurred within 0.75 m only.
Alauzet, Frédéric; Mohammadi, Bijan
2003-01-01
Ce rapport traite d'un problème d'optimisation de forme 3D du nez d'un SuperSonic Business Jet (SSBJ) sous des contraintes aérodynamiques et accoustiques. La contrainte accoustique concerne la génération du bang sonique par l'avion. On présente une méthode d'optimisation de faible dimension pour analyser l'impact du nez sur ces contraintes. Plus précisément, après avoir paramétrisé le nez de l'avion, on échantillonne l'espace de contrôle, puis on construit la surface de réponse qui nous donne...
Transport in complex magnetic geometries: 3D modelling of ergodic edge plasmas in fusion experiments
Runov, A. E-mail: runov@ipp.mpg.de; Kasilov, S.; Reiter, D.; McTaggart, N.; Bonnin, X.; Schneider, R
2003-03-01
Both stellarators and tokamaks can have quite complex magnetic topologies in the plasma edge. Special complexity is introduced by ergodic effects producing stochastic domains. Conventional numerical methods from fluid dynamics are not applicable in this case. In the present paper, we discuss two alternative possibilities. Our multiple coordinate system approach (MCSA) [Phys. Plasmas 8 (2001) 916] originally developed for the TEXTOR DED allows modelling of plasma transport in general magnetic field structures. The main idea of the concept is: magnetic field lines can exhibit truly stochastic behavior only for large distances (compared to the Kolmogorov length), while for smaller distances, the field remains regular. Thus, one can divide the computational domain into a finite set of sub-domains, introduce local magnetic coordinate systems in each and use an 'interpolated cell mapping' technique to switch between the neighboring coordinate systems. A 3D plasma fluid code (E3D, based upon MCSA) is applied to realistic geometries. We also introduce here some new details of the algorithm (stellarator option). The results obtained both for intrinsic (stellarator) and external (tokamak with ergodic divertor) perturbations of the magnetic field are discussed. Another approach, also using local coordinate systems, but based on more conventional finite difference methods, is also under development. Here, we present the outline of the algorithm and discuss its potential as compared to the Lagrangian Monte-Carlo approach.
Intérêt du guidage 3D et de la localisation des biopsies de prostate par voie endorectale
Mozer, Pierre; Chevreau, Grégoire; Troccaz, Jocelyne; Renard-Penna, Raphaëlle
2011-01-01
International audience La réalisation de biopsies de prostate, le plus souvent par voie endorectale, est primordiale pour le diagnostic et l'évaluation du pronostic du cancer. La précision de la localisation des biopsies est sujette à caution. Le développement de systèmes informatiques permet d'enregistrer avec précision leur localisation et de les guider pour améliorer leur distribution. Ces mêmes dispositifs permettent de fusionner images échographiques et images IRM et de fusionner diff...
Radon transport modelling: User's guide to RnMod3d
Andersen, Claus Erik
2000-01-01
RnMod3d is a numerical computer model of soil-gas and radon transport in porous media. It can be used, for example, to study radon entry from soil into houses in response to indoor-outdoor pressure differences or changes in atmospheric pressure. It canalso be used for flux calculations of radon...... from the soil surface or to model radon exhalation from building materials such as concrete. The finite-volume model is a technical research tool, and it cannot be used meaningfully without good understandingof the involved physical equations. Some understanding of numerical mathematics and the...... programming language Pascal is also required. Originally, the code was developed for internal use at Risø only. With this guide, however, it should be possible forothers to use the model. Three-dimensional steady-state or transient problems with Darcy flow of soil gas and combined generation, radioactive...
Jan eBartacek
2016-03-01
Full Text Available Description of processes such as bioaccumulation, bioavailability and biosorption of heavy metals in biofilm matrixes requires the quantification of their transport. This study shows 3D MRI measurements of the penetration of free (Fe2+, Co2+ and Gd3+ and complexed ([FeEDTA]2- and [GdDTPA]2- metal ions in a single methanogenic granule. Interactions (sorption or precipitation between free metals and the biofilm matrix result in extreme shortening of the spin-spin relaxation time (T2 and a decrease of the amplitude (A0 of the MRI signal, which hampers the quantification of the metal concentration inside the granular sludge matrix. MRI images clearly showed the presence of distinct regions (dead or living biomass, cracks and precipitates in the granular matrix, which influenced the metal transport. For the free metal ions, a reactive barrier was formed that moved through the granule, especially in the case of Gd3+. Chelated metals penetrated faster and without reaction front. Diffusion of [GdDTPA]2- could be quantified, revealing the course of its transport and the uneven (0.2 – 0.4 mmol·L-1 distribution of the final [GdDTPA]2- concentration within the granular biofilm matrix at equilibrium.
Krylov sub-space methods for K-eigenvalue problem in 3-D multigroup neutron transport
The K-eigenvalue problem in nuclear reactor physics is often formulated in the framework of Neutron Transport Theory. The fundamental mode solution of this problem is usually obtained by the Power Iteration method. The present report is concerned with the use of a Krylov Sub-Space method. called ORTHOMIN, to obtain a more efficient solution of the K-eigenvalue problem. A matrix-free approach is proposed which can be easily implemented by using a transport code which can perform fixed source calculations. The Power Iteration and ORTHOMIN schemes are compared for two realistic 3-D multi-group cases: an LWR benchmark and the AHWR Critical Facility. The within-group iterations over self-scattering source are required in the solution of K-eigenvalue problem. They are also accelerated using another Krylov method called Conjugate Gradient method. In this work, the discretisation of Transport Equation is based on fmite-differencing and Sn-method and isotropic scattering is considered. (author)
Multi-scale self-organisation of edge plasma turbulent transport in 3D global simulations
Tamain, P.; Ghendrih, Ph; Bufferand, H.; Ciraolo, G.; Colin, C.; Fedorczak, N.; Nace, N.; Schwander, F.; Serre, E.
2015-05-01
The 3D global edge turbulence code TOKAM3X is used to study the properties of edge particle turbulent transport in circular limited plasmas, including both closed and open flux surfaces. Turbulence is driven by an incoming particle flux from the core plasma and no scale separation between the equilibrium and the fluctuations is assumed. Simulations show the existence of a complex self-organization of turbulence transport coupling scales ranging from a few Larmor radii up to the machine scale. Particle transport is largely dominated by small scale turbulence with fluctuations forming quasi field-aligned filaments. Radial particle transport is intermittent and associated with the propagation of coherent structures on long distances via avalanches. Long range correlations are also found in the poloidal and toroidal direction. The statistical properties of fluctuations vary with the radial and poloidal directions, with larger fluctuation levels and intermittency found in the outboard scrape-off layer (SOL). Radial turbulent transport is strongly ballooned, with 90% of the flux at the separatrix flowing through the low-field side. One of the main consequences is the existence of quasi-sonic asymmetric parallel flows driving a net rotation of the plasma. Simulations also show the spontaneous onset of an intermittent E × B rotation characterized by a larger shear at the separatrix. Strong correlation is found between the turbulent particle flux and the E × B flow shear in a phenomenology reminiscent of H-mode physics. The poloidal position of the limiter is a key player in the observed dynamics.
Cost reduction and reliability increase are systematically pursued systems and components; this requires, amongst other, the availability of sophisticated computer programs and detailed analysis models. As an example, the core shroud, the structure having the function to maintain the core centered on its axis, is being designed in the Westinghouse AP1000, differently from previous plants, as a highly heterogeneous structure. Its thermal-mechanical sizing must take into due account accurately determined internal heat generation rates. The latter, if determined by combining 2D and 1D neutron and γ-ray calculations which imply the separation of spatial variables and are mainly applicable for fluxes in the reactor beltline region, may include overly conservative margins. On the other hand, Monte Carlo methods do not allow an easy quantification of the uncertainties related to overall calculation. Three-dimensional deterministic models, based on the discrete ordinate transport theory, have the potential to provide accurate design data; they can be also effective provided that the well-known difficulty to create and tune a complex geometrical model in a reasonable time is overcome and adequate computer resources are available to perform the calculation (until few years ago [Botta et al., 1996. Three-Dimensional Reactor Pressure Vessel Fast Neutron Fluence Calculations for the AP600 Using TORT, 3-D Deterministic Radiation Transport Computer Programs: Features, Applications and Perspectives, NEA/NSC/DOC, OECD/NEA. Paris, France], massive parallel computers (i.e. Cray Computers) available only to large national laboratories and selected industries had to be used). ANSALDO is acting as Westinghouse subcontractor and it supported Westinghouse in all AP1000 Licensing Process to NRC from 1999 to nowdays for the internal heating rate generation rate and RPV fluence calculations. As computer power growths up ANSALDO refined its calculation methodology in order to improve the
DANTE. A 3-D unstructured-mesh finite-element transport code
The DANTE code solves the standard multigroup Sn equations on 3-D unstructured finite-element meshes composed of arbitrary combinations of hexahedra and degenerate hexahedra (wedges, pyramids and tetrahedra). DANTE solves several second-order self-adjoint forms of the transport equation. This includes the standard even-parity and odd-parity equations, but also includes a new form of the transport equation that has the standard angular flux as its unknown rather than the even-parity or odd-parity component of the angular flux. DANTE also offers options for three different types of angular discretization: SPn, Sn and Pn. DANTE is written in FORTRAN 90 but uses a special MPI-based library, called PGSLIB, to define data array layouts over the processors and perform data communications between processors. This approach enables DANTE to be written in a SIMD fashion, yet be compatible with both SIMD and MIMD architectures. Computational results are given comparing solutions to the self-adjoint angular flux equation using the same spatial discretization scheme for both S-n and P-n angular discretizations. (R.P.)
Simulation of bacteria transport processes in a river with Flow3D
Schwarzwälder, Kordula; Bui, Minh Duc; Rutschmann, Peter
2014-05-01
Water quality aspects are getting more and more important due to the European water Framework directive (WFD). One problem related to this topic is the inflow of untreated wastewater due to combined sewer overflows into a river. The wastewater mixture contains even bacteria like E. coli and Enterococci which are markers for water quality. In our work we investigated the transport of these bacteria in river Isar by using a large-scale flume in the outside area of our lab (Oskar von Miller Institute). Therefor we could collect basic data and knowledge about the processes which occur during bacteria sedimentation and remobilisation. In our flume we could use the real grain with the exact size distribution curve as in the river Isar which we want to simulate and we had the chance to nurture a biofilm which is realistic for the analysed situation. This biofilm plays an important role in the remobilisation processes, because the bacteria are hindered to be washed out back into the bulk phase as fast and in such an amount as this would happen without biofilm. The results of our experiments are now used for a module in the 3D software Flow3D to simulate the effects of a point source inlet of raw wastewater on the water quality. Therefor we have to implement the bacteria not as a problem of concentration with advection and diffusion but as single particles which can be inactivated during the process of settling and need to be hindered from remobilisation by the biofilm. This biofilm has special characteristic, it is slippery and has a special thickness which influences the chance of bacteria being removed. To achieve realistic results we have to include the biofilm with more than a probabilistic-tool to make sure that our module is transferable. The module should be as flexible as possible to be improved step by step with increasing quality of dataset.
Application of the SDD-CMFD acceleration method to parallel 3-D MOC transport
In this paper the spatial domain decomposed coarse mesh finite difference (SDD-CMFD) method is applied as an acceleration technique to a parallel implementation of the 3-D method of characteristics (MOC) for a series of problems to assess the effectiveness of the method for practical applications. The SDD-CMFD method assumes the problem domain is divided into independent parallelizable sweep regions globally linked within the framework of a CMFD-like system. Results obtained with the MPACT code are examined for three problems. The first analysis is of multi-dimensional, 1-group, infinite homogeneous media problems that compare the numerically-measured rate of convergence to that predicted by the 1-D Fourier analysis performed in previous work. It is observed that the rate of convergence of the numerical experiments has similar behavior to that predicted by the Fourier analysis for variations of optical thickness in the coarse cell and spatial subdomain. However, the rate of convergence is measured to be slightly less than that predicted by Fourier analysis. The algorithm is applied to the Takeda 3-D neutron transport benchmark, and compared to a standard source iteration. In the analysis of this problem, the method is observed to speed up convergence, significantly reducing the number of outer iterations by a factor of nearly 20x and reducing the overall run time by a factor of about 10x. Finally, the method is applied to a realistic PWR assembly, which is observed to converge in 7 outer iterations, a factor of 150x less than source iteration, using the SDD-CMFD acceleration method, and have an estimated speedup of ∼34x over conventional source iteration. (author)
Thomas, Justin W.
2006-12-01
The Numerical Nuclear Reactor (NNR) is a code suite that is being developed to provide high-fidelity multi-physics capability for the analysis of light water nuclear reactors. The focus of the work here is to extend the capability of the NNR by incorporation of the neutronics module, DeCART, for Boiling Water Reactor (BWR) applications. The DeCART code has been coupled to the NNR fluid mechanics and heat transfer module STAR-CD for light water reactor applications. The coupling has been accomplished via an interface program, which is responsible for mapping the STAR-CD and DeCART meshes, managing communication, and monitoring convergence. DeCART obtains the solution of the 3-D Boltzmann transport equation by performing a series of 2-D modular ray tracing-based method of characteristics problems that are coupled within the framework of 3-D coarse-mesh finite difference. The relatively complex geometry and increased axial heterogeneity found in BWRs are beyond the modeling capability of the original version of DeCART. In this work, DeCART is extended in three primary areas. First, the geometric capability is generalized by extending the modular ray tracing scheme and permitting an unstructured mesh in the global finite difference kernel. Second, numerical instabilities, which arose as a result of the severe axial heterogeneity found in BWR cores, have been resolved. Third, an advanced nodal method has been implemented to improve the accuracy of the axial flux distribution. In this semi-analytic nodal method, the analytic solution to the transverse-integrated neutron diffusion equation is obtained, where the nonhomogeneous neutron source was first approximated by a quartic polynomial. The successful completion of these three tasks has allowed the application of the coupled DeCART/STAR-CD code to practical BWR problems.
Recent progress on the experimental identification and physics interpretation of 3D effects of magnetic field geometry/topology on divertor transport is overviewed. In this paper, the 3D effects are elucidated as a consequence of competition between transports parallel (∥) and perpendicular (⊥ ) to magnetic field, in open field lines cut by divertor plates, or in magnetic islands. The competition process has strong impacts on the divertor functions, such as density regime, impurity screening, and detachment control. The effects of magnetic perturbation on the edge electric field and turbulent transport are also discussed. Based on the experiments and numerical simulations, key parameters governing the 3D transport physics for the individual divertor functions, are discussed, suggesting demanding issues to be addressed for divertor optimization in future reactors. (author)
This document is a user's manual for the Rn3D finite element code. Rn3D was developed to simulate gas flow and radon transport in variably saturated, nonisothermal porous media. The Rn3D model is applicable to a wide range of problems involving radon transport in soil because it can simulate either steady-state or transient flow and transport in one-, two- or three-dimensions (including radially symmetric two-dimensional problems). The porous materials may be heterogeneous and anisotropic. This manual describes all pertinent mathematics related to the governing, boundary, and constitutive equations of the model, as well as the development of the finite element equations used in the code. Instructions are given for constructing Rn3D input files and executing the code, as well as a description of all output files generated by the code. Five verification problems are given that test various aspects of code operation, complete with example input files, FORTRAN programs for the respective analytical solutions, and plots of model results. An example simulation is presented to illustrate the type of problem Rn3D is designed to solve. Finally, instructions are given on how to convert Rn3D to simulate systems other than radon, air, and water
Solution of the neutron transport equation by the collision probability method for 3D geometries
The TDT code solves the multigroup transport equation by the interface-current method for unstructured 2D geometries. This works presents the extension of TDT to the treatment of 3D geometries obtained by axial displacement of unstructured 2D geometries. Three-dimensional trajectories are obtained by lifting the 2D trajectories. The code allows for the definition of macro-domains in the axial direction to be used in interface-current method. Specular and isotropic reflection or translations boundary conditions can be applied to the horizontal boundaries of the domain. Numerical studies have shown the need for longer trajectory cutoffs for trajectories intersecting horizontal boundaries. Numerical applications to the calculation of local power peaks are given in a second part for: the local destruction of a Pyrex absorbent, inter-assembly (U02-MOX) power distortion due to pellet collapsing at the top of the core. Calculations with 16 groups were performed by coupling TDT to the spectral code APOLLO2. One-group comparisons with the Monte Carlo code TRIMARAN2 are also given. (author)
Solution of the neutron transport equation by the collision probability for 3D geometries
The TDT code solves the multigroup transport equation by the interface current method for unstructured 2D geometries. This works presents the extension of TDT to the treatment of 3D geometries obtained by axial displacement of unstructured 2D geometries. Three-dimensional trajectories are obtained by lifting the 2D trajectories. The code allows for the definition of macro-domains in the axial direction to be used in the interface-current method. Specular and isotropic reflection or translations boundary conditions can be applied to the horizontal boundaries of the domain. Numerical studies have shown the need for longer trajectory cutoffs for trajectories intersecting horizontal boundaries. Numerical applications to the calculation of local power peaks are given in a second part for: the local destruction of a Pyrex absorbent and inter-assembly (UO2-MOX) power distortion due to pellet collapsing at the top of the core. Calculations with 16 groups were performed by coupling TDT to the spectral code APOLLO2. One-group comparisons with the Monte Carlo code TRIMARAN2 are also given. (author)
A parametric study of mucociliary transport by numerical simulations of 3D non-homogeneous mucus.
Chatelin, Robin; Poncet, Philippe
2016-06-14
Mucociliary clearance is the natural flow of the mucus which covers and protects the lung from the outer world. Pathologies, like cystic fibrosis, highly change the biological parameters of the mucus flow leading to stagnation situations and pathogens proliferation. As the lung exhibits a complex dyadic structure, in-vivo experimental study of mucociliary clearance is almost impossible and numerical simulations can bring important knowledge about this biological flow. This paper brings a detailed study of the biological parameters influence on the mucociliary clearance, in particular for pathological situations such as cystic fibrosis. Using recent suitable numerical methods, a non-homogeneous mucus flow (including non-linearities) can be simulated efficiently in 3D, allowing the identification of the meaningful parameters involved in this biological flow. Among these parameters, it is shown that the mucus viscosity, the stiffness transition between pericilliary fluid and mucus, the pericilliary fluid height as well as both cilia length and beating frequency have a great influence on the mucociliary transport. PMID:27126985
L’AUTONOMIE DU CONTRAT DE TRANSPORT
Ana CĂLIN
2006-01-01
Full Text Available The autonomy of the transport contract was developed over time having as basis few elements of legislation. Practice was the one that, in need of moving goods and persons, outlined the elements that are the basis of the transport contract. It was said that it is a civil or a commercial contract, which is distinguished by the quality of trader or non-trader of the carter. The essential element that distinguishes it from other contracts is that during the execution of the transport contract there are involved three persons, namely: the consignor, the carter and the consignee.The legal form and the autonomy of the transport contract result from the fact that there is a real and a consensual contract, that has an economic content in different ways; the parties of the transport contract must understand that the general conditions on the ability to control the consent lawfully expressed, has a determined object, licit and moral feature and the form required by law. It is a commutative contract. The transport contract is concluded in written form. E. Cristoforeanu, Constantin Stătescu, Cezare Vivante investigated about the autonomy’s development and stability of the transport contract. Such distinguished personalities expressed their opinions regarding the definition of transport contract as an autonomous contract, even though it borrowed elements of civil law and commercial law.
Chihi, H.
1997-05-12
This work aims at providing a contribution to the studies carried out on reservoir characterization by use of seismic data. The study mainly consisted in the use of geostatistical methods in order to model the geometry of stratigraphic units of the Golfe du Lion margin and to simulate the seismic facies from high resolution seismic data. We propose, for the geometric modelling, a methodology based on the estimation of the surfaces and calculation afterwards of the thicknesses, if the modelling of the depth is possible. On the other hand the method consists in estimating the thickness variable directly and in deducing the boundary surfaces afterwards. In order to simulate the distribution of seismic facies within the units of the western domain, we used the truncated Gaussian method. The used approach gave a satisfactory results, when the seismic facies present slightly dipping reflectors with respect to the reference level. Otherwise the method reaches its limits because of the problems of definition of a reference level which allows to follow the clino-forms. In spite of these difficulties, this simulation allows us to estimate the distribution of seismic facies within the units and then to deduce their probable extension. (author) 150 refs.
L’AUTONOMIE DU CONTRAT DE TRANSPORT
Ana CĂLIN
2006-01-01
The autonomy of the transport contract was developed over time having as basis few elements of legislation. Practice was the one that, in need of moving goods and persons, outlined the elements that are the basis of the transport contract. It was said that it is a civil or a commercial contract, which is distinguished by the quality of trader or non-trader of the carter. The essential element that distinguishes it from other contracts is that during the execution of the transport contract the...
Albedo and heat transport in 3-D model simulations of the early Archean climate
H. Kienert
2013-08-01
Full Text Available At the beginning of the Archean eon (ca. 3.8 billion years ago, the Earth's climate state was significantly different from today due to the lower solar luminosity, smaller continental fraction, higher rotation rate and, presumably, significantly larger greenhouse gas concentrations. All these aspects play a role in solutions to the "faint young Sun paradox" which must explain why the ocean surface was not fully frozen at that time. Here, we present 3-D model simulations of climate states that are consistent with early Archean boundary conditions and have different CO2 concentrations, aiming at an understanding of the fundamental characteristics of the early Archean climate system. In order to do so, we have appropriately modified an intermediate complexity climate model that couples a statistical-dynamical atmosphere model (involving parameterizations of the dynamics to an ocean general circulation model and a thermodynamic-dynamic sea-ice model. We focus on three states: one of them is ice-free, one has the same mean surface air temperature of 288 K as today's Earth and the third one is the coldest stable state in which there is still an area with liquid surface water (i.e. the critical state at the transition to a "snowball Earth". We find a reduction in meridional heat transport compared to today, which leads to a steeper latitudinal temperature profile and has atmospheric as well as oceanic contributions. Ocean surface velocities are largely zonal, and the strength of the atmospheric meridional circulation is significantly reduced in all three states. These aspects contribute to the observed relation between global mean temperature and albedo, which we suggest as a parameterization of the ice-albedo feedback for 1-D model simulations of the early Archean and thus the faint young Sun problem.
Gastebois, Sabrina; Fourment, Lionel
2013-01-01
Le procédé FSW est un procédé de soudage par frottement et malaxage dont la complexité résulte d'un très fort couplage thermomécanique. Nous présentons une nouvelle formulation Arbitrairement Lagrangienne ou Eulérienne (ALE) en vue de le modéliser avec précision. Son utilisation montre qu'elle est parfaitement adaptée à la simulation du FSW en 3D. Elle permet notamment de simuler des soudures de qualité ou la formation de défauts tels que les bavures ou les trous tunnels qui peuvent apparaîtr...
An iterative KP1 method for solving the transport equation in 3D domains on unstructured grids
Kokonkov, N. I.; Nikolaeva, O. V.
2015-10-01
A two-step iterative KP1 method for solving systems of grid equations that approximate the integro-differential transport equation in 3D domains on unstructured grids using nodal SN methods is described. Results of testing the efficiency of the proposed method in solving benchmark problems of reactor protection on tetrahedral grids are presented.
It is shown that the combination of 3D neutron transport calculations and the results from activation foil measurements at a limited number of locations in a materials testing irradiation experiment can provide information at any position in the experiment for detailed neutron dosimetry and damage analysis. 4 refs
Cevidanes, Lucia H. S.; Styner, Martin; Proffit, William R.; Ngom, Traduit par Papa Ibrahima
2009-01-01
RÉSUMÉ – Pour évaluer les modifications liées à la croissance ou au traitement, il est nécessaire de superposer les céphalogrammes successifs sur une structure stable. En céphalométrie bidimensionnelle (2-D), la base du crâne est souvent utilisée pour les superpositions parce que les changements qu’elle subit après le développement cérébral sont mineurs. Toutefois, sur les céphalogrammes de profil et de face, les points de repère basicraniens sont peu fiables. Dans cet article, nous présenton...
A deterministic particle-tracking code (TRACK3D) has been developed to compute convective flow paths of conservative (nonreactive) contaminants through porous geological media. TRACK3D requires the groundwater velocity distribution, which, in our applications, results from flow simulations using AECL's MOTIF code. The MOTIF finite-element code solves the transient and steady-state coupled equations of groundwater flow, solute transport and heat transport in fractured/porous media. With few modifications, TRACK3D can be used to analyse the velocity distributions calculated by other finite-element or finite-difference flow codes. TRACK3D temporarily integrates the velocity distribution, in conjunction with the model geometry, to calculate convective flow paths, exit locations and travel times of as many as 1000 water-coincident particles released in the flow domain. Both steady-state and time-varying velocity distributions can be handled. TRACK3D requires the flow domain to be discretized by a finite-element mesh containing as many as 25 000 elements. The mesh can contain three-dimensional (3-D) eight-noded hexahedral elements representing a solid region, or two-dimensional four-noded quadrilateral elements representing a plane, which can be oriented arbitrarily in 3-D space. TRACK3D has been verified by comparison with analytical and numerical solutions, and in an independent confirmation by Ontario Hydro Research. This report describes the assumptions, limitations, organization, operation and applications of the TRACK3D code, and provides a comprehensive user's manual. TRACK3D has been applied by AECL Research in the concept assessment phase of the Canadian Nuclear Fuel Waste Management Program to analyse convective radionuclide pathways and travel times from a hypothetical vault containing (for example) CANDU reactor fuel waste, through the surrounding geologic formations to discharge locations in the biosphere. The program has been used to examine the sensitivity
Delphine Lacanette
2012-04-01
Full Text Available La simulation numérique en mécanique des fluides est appliquée ici à la conservation du patrimoine et plus particulièrement à la grotte de Lascaux en Dordogne. Un relevé laser 3D très précis de la grotte de plus de 150 millions de points a servi de base au simulateur Lascaux, outil numérique permettant de tester en laboratoire, sur ordinateur, les modifications à apporter éventuellement à la cavité et de vérifier la façon dont elle réagit avant des réaliser ces changements in situ. Il est en cela un outil de conservation préventive innovant.Numerical simulation in fluid mechanics is applied here to the conservation of the patrimony and more particularly to the Lascaux cave, in Dordogne, France. A very accurate 3D laser survey of the cavity of more than 150 million points was used as a base of the Lascaux simulator, a numerical tool allowing to test in laboratory, on a computer, the modifications to bring eventually to the cave, and to check the way it reacts before achieving these modifications in situ. The simulator is an innovative conserving tool for preventive conservation.
Udphuay, S.; Everett, M. E.; Guenther, T.; Warden, R. R.
2007-12-01
The D-Day invasion site at Pointe du Hoc in Normandy, France is one of the most important World War II battlefields. The site remains today a valuable historic cultural resource. However the site is vulnerable to cliff collapses that could endanger the observation post building and U.S. Ranger memorial located just landward of the sea stack, and an anti-aircraft gun emplacement, Col. Rudder's command post, located on the cliff edge about 200 m east of the observation post. A 3-D resistivity tomography incorporating extreme topography is used in this study to provide a detailed site stability assessment with special attention to these two buildings. Multi-electrode resistivity measurements were made across the cliff face and along the top of the cliff around the two at-risk buildings to map major subsurface fracture zones and void spaces that could indicate possible accumulations and pathways of groundwater. The ingress of acidic groundwater through the underlying carbonate formations enlarges pre-existing tectonic fractures via limestone dissolution and weakens the overall structural integrity of the cliff. The achieved 3-D resistivity tomograms provide diagnostic subsurface resistivity distributions. Resistive zones associated with subsurface void spaces have been located. These void spaces constitute a stability geohazard as they become significant drainage routes during and after periods of heavy rainfalls.
S. Dhomse
2011-12-01
Full Text Available We have used an off-line 3-D chemical transport model (CTM to investigate the 11-yr solar cycle response in tropical stratospheric ozone. The model is forced with European Centre for Medium-Range Weather Forecasts (ECMWF (reanalysis (ERA-40/operational and ERA-Interim data for the 1979–2005 time period. We have compared the modelled solar response in ozone to observation-based data sets that are constructed using satellite instruments such as Total Ozone Mapping Spectrometer (TOMS, Solar Backscatter UltraViolet instrument (SBUV, Stratospheric Aerosol and Gas Experiment (SAGE and Halogen Occultation Experiment (HALOE. A significant difference is seen between simulated and observed ozone during the 1980s, which is probably due to inhomogeneities in the ERA-40 reanalyses. In general, the model with ERA-Interim dynamics shows better agreement with the observations from 1990 onwards than with ERA-40. Overall both standard model simulations are partially able to simulate a "double peak"-structured ozone solar response with a minimum around 30 km, and these are in better agreement with HALOE than SAGE-corrected SBUV (SBUV/SAGE or SAGE-based data sets. In the tropical lower stratosphere (TLS, the modelled solar response with time-varying aerosols is amplified through aliasing with a volcanic signal, as the model overestimates ozone loss during high aerosol loading years. However, the modelled solar response with fixed dynamics and constant aerosols shows a positive signal which is in better agreement with SBUV/SAGE and SAGE-based data sets in the TLS. Our model simulations suggests that photochemistry contributes to the ozone solar response in this region. The largest model-observation differences occur in the upper stratosphere where SBUV/SAGE and SAGE-based data show a significant (up to 4% solar response whereas the standard model and HALOE do not. This is partly due to a positive solar response in the ECMWF upper stratospheric temperatures which
Finite-element discretization of 3D energy-transport equations for semiconductors
Gadau, Stephan
2007-07-01
demonstrated in detail. We compare these new iterations with a standard method that is complemented by a feature to fit in the current context. A further innovation is the computation of solutions in three-dimensional domains, which are still rare. Special attention is paid to applicability of the 3D simulation tools. The programs are designed to have justifiable working complexity. The simulation results of some models of contemporary semiconductor devices are shown and detailed comments on the results are given. Eventually, we make a prospect on future development and enhancements of the models and of the algorithms that we used. (orig.)
Opara A.I.
2012-05-01
Full Text Available The deep drilling campaign in the Niger Delta has demonstrated the need for a detailed geopressure and trap integrity (drilling margin analysis as an integral and required step in prospect appraisal. Pre-drill pore pressure prediction from 3-D seismic data was carried out in the Greater Ughelli depobelt, Niger Delta basin to predict subsurface pressure regimes and further applied in the determination of hydrocarbon column height, reservoir continuity, fault seal and trap integrity. Results revealed that geopressured sedimentary formations are common within the more prolific deeper hydrocarbon reserves in the Niger Delta basin. The depth to top of mild geopressure (0.60 psi/ft ranges from about 10 000 ftss to over 30 000 ftss. The distribution of geopressures shows a well defined trend with depth to top of geopressures increasing towards the central part of the basin. This variation in the depth of top of geopressures in the area is believed to be related to faulting and shale diapirism, with top of geopressures becoming shallow with shale diapirism and deep with sedimentation. Post-depositional faulting is believed to have controlled the configuration of the geopressure surface and has played later roles in modifying the present day depth to top of geopressures. In general, geopressure in this area is often associated with simple rollover structures bounded by growth faults, especially at the hanging walls, while hydrostatic pressures were observed in areas with k-faults and collapsed crested structures. Les campagnes de forages profonds dans le delta du Niger ont démontré la nécessité d’une analyse détaillée des surpressions et de l’intégrité des structures pour évaluer correctement les prospects. La prédiction des pressions interstitielles a pu être réalisée ici avant forage à partir de données sismiques 3-D du grand sous-bassin d’Ughelli, dans le delta du Niger. Ce travail a permis de prévoir les régimes de pression du
3-D Deep Penetration Neutron Imaging of Thick Absorgin and Diffusive Objects Using Transport Theory
Ragusa, Jean; Bangerth, Wolfgang
2011-08-01
A current area of research interest in national security is to effectively and efficiently determine the contents of the many shipping containers that enter ports in the United States. This interest comes as a result of the 9/11 Commission Act passed by Congress in 2007 that requires 100% of inbound cargo to be scanned by 2012. It appears that this requirement will be achieved by 2012, but as of February of 2009 eighty percent of the 11.5 million inbound cargo containers were being scanned. The systems used today in all major U.S. ports to determine the presence of radioactive material within cargo containers are Radiation Portal Monitors (RPM). These devices generally exist in the form of a gate or series of gates that the containers can be driven through and scanned. The monitors are effective for determining the presence of radiation, but offer little more information about the particular source. This simple pass-fail system leads to many false alarms as many everyday items emit radiation including smoke detectors due to the Americium-241 source contained inside, bananas, milk, cocoa powder and lean beef due to the trace amounts of Potassium-40, and fire brick and kitty litter due to their high clay content which often contains traces of uranium and thorium. In addition, if an illuminating source is imposed on the boundary of the container, the contents of the container may become activated. These materials include steel, aluminum and many agricultural products. Current portal monitors also have not proven to be that effective at identifying natural or highly enriched uranium (HEU). In fact, the best available Advanced Spectroscopic Portal Monitors (ASP) are only capable of identifying bare HEU 70-88% of the time and masked HEU and depleted uranium (DU) only 53 percent of the time. Therefore, a better algorithm that uses more information collected from better detectors about the specific material distribution within the container is desired. The work reported
Building Accurate 3D Spatial Networks to Enable Next Generation Intelligent Transportation Systems
Kaul, Manohar; Yang, Bin; Jensen, Christian S.
2013-01-01
model with elevation information extracted from massive aerial laser scan data and thus yields an accurate 3D model. We present a filtering technique that is capable of pruning irrelevant laser scan points in a single pass, but assumes that the 2D network fits in internal memory and that the points are...
3D Space Radiation Transport in a Shielded ICRU Tissue Sphere
Wilson, John W.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.
2014-01-01
A computationally efficient 3DHZETRN code capable of simulating High Charge (Z) and Energy (HZE) and light ions (including neutrons) under space-like boundary conditions with enhanced neutron and light ion propagation was recently developed for a simple homogeneous shield object. Monte Carlo benchmarks were used to verify the methodology in slab and spherical geometry, and the 3D corrections were shown to provide significant improvement over the straight-ahead approximation in some cases. In the present report, the new algorithms with well-defined convergence criteria are extended to inhomogeneous media within a shielded tissue slab and a shielded tissue sphere and tested against Monte Carlo simulation to verify the solution methods. The 3D corrections are again found to more accurately describe the neutron and light ion fluence spectra as compared to the straight-ahead approximation. These computationally efficient methods provide a basis for software capable of space shield analysis and optimization.
Hybrid methods of neutron transport have increased greatly in use, for example, in applications of using both Monte Carlo and deterministic transport methods to calculate quantities of interest, such as the flux and eigenvalue in a nuclear reactor. Many 3d parallel Sn codes apply a Cartesian mesh, and thus for nuclear reactors the representation of curved fuels (cylinder, sphere, etc.) are impacted in the representation of proper fuel inventory, resulting in both a deviation of mass and exact geometry in the computer model representation. In addition, we discuss auto-conversion techniques with our 3d Cartesian mesh generation tools to allow for full generation of MCNP5 inputs (Cartesian mesh and Multigroup XS) from a basis PENTRAN Sn model. For a PWR assembly eigenvalue problem, we explore the errors associated with this Cartesian discrete mesh representation, and perform an analysis to calculate a slope parameter that relates the pcm to the percent areal/volumetric deviation (areal → 2d problems, volumetric → 3d problems). This paper analysis demonstrates a linear relationship between pcm change and areal/volumetric deviation using Multigroup MCNP on a PWR assembly compared to a reference exact combinatorial MCNP geometry calculation. For the same MCNP multigroup problems, we also characterize this linear relationship in discrete ordinates (3d PENTRAN). Finally, for 3D Sn models, we show an application of corner fractioning, a volume-weighted recovery of underrepresented target fuel mass that reduced pcm error to < 100, compared to reference Monte Carlo, in the application to a PWR assembly. (author)
Klimeck, Gerhard; Luisier, Mathieu
2008-01-01
Lessons learned in 15 years of NEMO development starting from quantitative and predictive resonant tunneling diode (RTD) to multi-million atom electronic structure modeling and the path for OMEN are laid out. The recent OMEN capabilities enable realistically large 3D atomistic nano-scale device simulation.
Daughney, C.; Toews, M. W.; Morgenstern, U.; Cornaton, F. J.; Jackson, B. M.
2013-12-01
Lake Rotorua is a focus of culture and tourism in New Zealand. The lake's water quality has declined since the 1970s, partly due to nutrient inputs that reach the lake via the groundwater system. Improved land use management within the catchment requires prediction of the spatial variations of groundwater transit time from land surface to the lake, and from this the prediction of current and future nutrient inflows to the lake. This study combines the two main methods currently available for determination of water age: numerical groundwater models and hydrological tracers. A steady-state 3D finite element model was constructed to simulate groundwater flow and transport of tritium and age at the catchment scale (555 km2). The model materials were defined using a 3D geologic model and included ignimbrites, rhyolites, alluvial and lake bottom sediments. The steady-state saturated groundwater flow model was calibrated using observed groundwater levels in boreholes (111 locations) and stream flow measurements from groundwater-fed streams and springs (61 locations). Hydraulic conductivities and Cauchy boundary conditions associated with the streams, springs and lake were parameterized. The transport parameters for the model were calibrated using 191 tritium samples from 105 locations (springs, streams and boreholes), with most locations having two sample dates. The transport model used steady-state flow, but simulated the transient transport and decay of tritium from rainfall recharge between 1945 and 2012. An additional 1D unsaturated sub-model was added to account for tritium decay from the ground surface to the water table. The sub-model is linked on top of the 3D model, and uses the water table depths and material properties from the 3D model. The adjustable calibration parameters for the transport model were porosity and van Genuchten parameters related to the unsaturated sub-models. Calibration of the flow model was achieved using a combination of automated least
Talukdar, P.; Steven, M.; Issendorff, F.V.; Trimis, D. [Institute of Fluid Mechanics (LSTM), University of Erlangen-Nuremberg, Cauerstrasse 4, D 91058 Erlangen (Germany)
2005-10-01
The finite volume method of radiation is implemented for complex 3-D problems in order to use it for combined heat transfer problems in connection with CFD codes. The method is applied for a 3-D block structured grid in a radiatively participating medium. The method is implemented in non-orthogonal curvilinear coordinates so that it can handle irregular structure with a body-fitted structured grid. The multiblocking is performed with overlapping blocks to exchange the information between the blocks. Five test problems are considered in this work. In the first problem, present work is validated with the results of the literature. To check the accuracy of multiblocking, a single block is divided into four blocks and results are validated against the results of the single block simulated alone in the second problem. Complicated geometries are considered to show the applicability of the present procedure in the last three problems. Both radiative and non-radiative equilibrium situations are considered along with an absorbing, emitting and scattering medium. (author)
Contaminated groundwater transport using an adaptive 3-D finite element model
A three-dimensional, h-adapting finite element model has been developed to calculate subsurface transport and dispersion of contaminant. The model is based on a hybrid finite element scheme previously developed for two-dimensional groundwater and species transport
Volatile transport on inhomogeneous surfaces: II. Numerical calculations (VT3D)
Young, Leslie A
2015-01-01
Several distant icy worlds have atmospheres that are in vapor-pressure equilibrium with their surface volatiles, including Pluto, Triton, and, probably, several large KBOs near perihelion. Studies of the volatile and thermal evolution of these have been limited by computational speed, especially for models that treat surfaces that vary with both latitude and longitude. In order to expedite such work, I present a new numerical model for the seasonal behavior of Pluto and Triton which (i) uses initial conditions that improve convergence, (ii) uses an expedient method for handling the transition between global and non-global atmospheres, (iii) includes local conservation of energy and global conservation of mass to partition energy between heating, conduction, and sublimation or condensation, (iv) uses time-stepping algorithms that ensure stability while allowing larger timesteps, and (v) can include longitudinal variability. This model, called VT3D, has been used in Young (2012), Young (2013), Olkin et al. (201...
High-energy particle transport in 3D hydrodynamic models of colliding-wind binaries
Reitberger, K; Reimer, A; Dubus, G; Reimer, O
2014-01-01
Massive stars in binary systems (as WR140, WR147 or $\\eta$ Carinae) have long been regarded as potential sources of high-energy $\\gamma$-rays. The emission is thought to arise in the region where the stellar winds collide and produce relativistic particles which subsequently might be able to emit $\\gamma$-rays. Detailed numerical hydrodynamic simulations have already offered insight in the complex dynamics of the wind collision region (WCR), while independent analytical studies, albeit with simplified descriptions of the WCR, have shed light on the spectra of charged particles. In this paper, we describe a combination of these two approaches. We present a 3D-hydrodynamical model for colliding stellar winds and compute spectral energy distributions of relativistic particles for the resulting structure of the WCR. The hydrodynamic part of our model incorporates the line-driven acceleration of the winds, gravity, orbital motion and the radiative cooling of the shocked plasma. In our treatment of charged particle...
In this paper we combine a stochastic 3D microstructure model of a fiber based gas diffusion layer of polymer electrolyte fuel cells with a Lattice Boltzmann model for fluid transport. We focus on a simple approach of compressing the planar oriented virtual geometry of paper-type gas diffusion layer from Toray. Material parameters – permeability and tortuosity – are calculated from simulation of one phase, one component gas flow in stochastic geometries. We analyze the statistical spread of simulation results on ensembles of the virtual geometry, both uncompressed and compressed. The influence of the compression is discussed with regard to the Kozeny–Carman equation. The effective transport properties calculated from transport simulations in compressed gas diffusion layers agree well with a trend based on the Kozeny–Carman equation
Bentzen, Thomas Ruby
2010-01-01
The paper presents results from an experimental and numerical study of flows and transport of primarily particle bound pollutants in highway wet detention ponds. The study presented here is part of a general investigation on road runoff and pollution in respect to wet detention ponds. The objecti...
Applications of the 3-D Deterministic Transport Code Attlla for Core Safety Analysis
D. S. Lucas
2004-10-01
An LDRD (Laboratory Directed Research and Development) project is ongoing at the Idaho National Engineering and Environmental Laboratory (INEEL) for applying the three-dimensional multi-group deterministic neutron transport code (Attila®) to criticality, flux and depletion calculations of the Advanced Test Reactor (ATR). This paper discusses the model development, capabilities of Attila, generation of the cross-section libraries, and comparisons to an ATR MCNP model and future.
Applications of the 3-D Deterministic Transport Attila{reg_sign} for Core Safety Analysis
Lucas, D.S.; Gougar, D.; Roth, P.A.; Wareing, T.; Failla, G.; McGhee, J.; Barnett, A.
2004-10-06
An LDRD (Laboratory Directed Research and Development) project is ongoing at the Idaho National Engineering and Environmental Laboratory (INEEL) for applying the three-dimensional multi-group deterministic neutron transport code (Attila{reg_sign}) to criticality, flux and depletion calculations of the Advanced Test Reactor (ATR). This paper discusses the model development, capabilities of Attila, generation of the cross-section libraries, and comparisons to an ATR MCNP model and future.
Chaudhuri, A; Sekhar, M.
2006-01-01
During probabilistic analysis of ﬂow and transport in porous media, the uncertainty due to spatial heterogeneity of governing parameters are often taken into account. The randomness in the source conditions also play a major role on the stochastic behavior in distribution of the dependent variable. The present paper is focused on studying the eﬀect of both uncertainty in the governing system parameters as well as the input source conditions. Under such circumstances, a method is proposed whic...
Importance of 3D Processes Near the Ocean's Surface for Material Transport
Ozgokmen, T. M.
2014-12-01
There are a number of practical problems that demand an accurate knowledge of ocean currents near the surface of the ocean. It is known that oceanic coherent features transport heat and carry out vertical exchange of biogeochemical tracers. Ocean currents can affect biological primary production, air-sea gas exchanges and global tracer budgets. Ocean currents are also important for the dispersion of substances that pose a danger to society, economy and human health. Examples of such events include algal blooms, the Fukushima nuclear plant incident in the Pacific Ocean in 2011, and repeated large oil spills in the Gulf of Mexico, namely the IXTOC in 1978 and the Deepwater Horizon event in 2010. Such incidents demand accurate answers to questions such as ``where will the pollutant go?", ``how fast will it get there?" and ``how much pollutant will arrive there?", and in some instances ``where did the pollutant come from?". The answers to these questions are critical to the allocation of limited response resources, and in determining the overall impact of the events. We will summarize the efforts by the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE). One of the primary objectives of CARTHE is to improve predictive modeling capability for flows near the air-sea interface. In particular, two large experiments, Grand Lagrangian Deployment (GLAD) and Surf-zone and Coastal Oil Pathways Experiment (SCOPE), coordinated with real-time modeling were instructive on processes influencing near-surface material transport. Findings on submesoscale flows as well as model deficiencies to capture processes relevant to transport will be discussed. Insight into future modeling and observational plans will be provided.
SWENT, 3-D Fluid, Heat, Radionuclide Transport in Heterogeneous Geologic Medium
1 - Description of program or function: SWENT (Simulator for Water, Energy, and Nuclide Transport) simulates the transient transport of fluid, heat, an inert component, and any number of radionuclides through a heterogeneous geologic medium either in three dimensional or radial geometries. The first three transport processes are coupled by the fluid properties of density and viscosity. The velocity field is derived from the solution of the coupled processes and used in the fourth process. Since radionuclides are present in trace quantities only, this process is not coupled to the first three. Aquifer porosity is treated as a function of pressure. 2 - Method of solution: The resulting system of nonlinear partial differential equations is solved by finite-difference approximations, suitable linearization schemes, and an iterative technique to reduce the errors that arise in linearization. 3 - Restrictions on the complexity of the problem: In the current release, the simulations are limited to maxima of 20 wells, 7 overburden vertical layers, 7 under-burden vertical layers, 50 entries in the aquifer influence function tables, and 10 entries in each of the viscosity versus temperature and concentration tables
Janssen, G.; Del Val Alonso, L.; Groenendijk, P.; Griffioen, J.
2012-12-01
We developed an on-line coupling between the 1D/quasi-2D nutrient transport model ANIMO and the 3D groundwater transport model code MT3DMS. ANIMO is a detailed, process-oriented model code for the simulation of nitrate leaching to groundwater, N- and P-loads on surface waters and emissions of greenhouse gasses. It is the leading nutrient fate and transport code in the Netherlands where it is used primarily for the evaluation of fertilization related legislation. In addition, the code is applied frequently in international research projects. MT3DMS is probably the most commonly used groundwater solute transport package worldwide. The on-line model coupling ANIMO-MT3DMS combines the state-of-the-art descriptions of the biogeochemical cycles in ANIMO with the advantages of using a 3D approach for the transport through the saturated domain. These advantages include accounting for regional lateral transport, considering groundwater-surface water interactions more explicitly, and the possibility of using MODFLOW to obtain the flow fields. An additional merit of the on-line coupling concept is that it preserves feedbacks between the saturated and unsaturated zone. We tested ANIMO-MT3DMS by simulating nutrient transport for the period 1970-2007 in a Dutch agricultural polder catchment covering an area of 118 km2. The transient groundwater flow field had a temporal resolution of one day and was calculated with MODFLOW-MetaSWAP. The horizontal resolution of the model grid was 100x100m and consisted of 25 layers of varying thickness. To keep computation times manageable, we prepared MT3DMS for parallel computing, which in itself is a relevant development for a large community of groundwater transport modelers. For the parameterization of the soil, we applied a standard classification approach, representing the area by 60 units with unique combinations of soil type, land use and geohydrological setting. For the geochemical parameterization of the deeper subsurface, however, we
Codes complex for quick transport 3D neutron calculations of WWER
: more numbers of groups, more high approximations for angle distributions. The code is used for carrying out 3D coarse mesh calculation. The 6F approximation of the Surface Harmonics Method is sufficient for WWER calculations. The complex Surface Values System is convenient for calculations of the core with the monitoring and control system and it is verificated for work with shell KRUIS, that used on some AES with the reactors WWER (Authors)
3-D Monte Carlo neutron-photon transport code JMCT and its algorithms
JMCT Monte Carlo neutron and photon transport code has been developed which is based on the JCOGIN toolbox. JCOGIN includes the geometry operation, tally, the domain decomposition and the parallel computation about particle (MPI) and spatial domain (OpenMP) etc. The viewdata of CAD is equipped in JMCT preprocessor. The full-core pin-mode, which is from Chinese Qinshan-II nuclear power station, is design and simulated by JMCT. The detail pin-power distribution and keff results are shown in this paper. (author)
3-D radiation transport benchmarks for simple geometries with void regions
Industry requires well-validated computation methods and computer codes for its nuclear applications. The predictive power of such tools must be established and users must be confident of their results. Model refinement requires that increasingly sophisticated tools be used. Moreover, the computing power available today no longer justifies a number of geometrical simplifications. This report describes the results of challenging international benchmarks in three-dimensional radiation transport that contribute to the evaluation and validation of state-of-the-art computation methods and computer codes. It will be of particular interest to reactor physicists and radiation shielding specialists. (author)
The first 3D structural model of an eukaryotic heteromeric aminoacid transporter
Costa i Torres, Meritxell
2012-01-01
[eng] Introduction Heteromeric amino acid transporters (HATs) are composed of a heavy subunit (rBAT or 4F2hc) and a light subunit (b0 + AT, ASC1, LAT1, LAT2, y + LAT1, y + LAT2 and xCT), joined by a disulfide bridge (Chillaron et al. 2001). rBAT and 4F2hc are type II membrane glycoproteins (N-terminal cytoplasmic). Both have a single transmembrane segment, an N-terminal intracellular tail and an extracellular domain (ectodomain). As far as we know, the role of the heavy subunit is facilit...
Time-dependent 3-D deterministic transport on parallel architectures using DANTSYS/MPI
In addition to the ability to solve the static transport equation, time dependence was incorporated into DANTSYS/MPI. Using a semi-implicit scheme, DANTSYS/MPI is capable of performing time-dependent calculations for such problems as nuclear well logging. The form of the time-dependent equations implemented, their solution strategies in DANTSYS/MPI including iteration acceleration, and the strategies used for time-step control are described. Results are presented for a model nuclear well logging calculation. (author)
A spherical harmonics research code (DANTE) has been developed which is compatible with parallel computer architectures. DANTE provides 3-D, multi-material, deterministic, transport capabilities using an arbitrary finite element mesh. The linearized Boltzmann transport equation is solved in a second order self-adjoint form utilizing a Galerkin finite element spatial differencing scheme. The core solver utilizes a preconditioned conjugate gradient algorithm. Other distinguishing features of the code include options for discrete-ordinates and simplified spherical harmonics angular differencing, an exact Marshak boundary treatment for arbitrarily oriented boundary faces, in-line matrix construction techniques to minimize memory consumption, and an effective diffusion based preconditioner for scattering dominated problems. Algorithm efficiency is demonstrated for a massively parallel SIMD architecture (CM-5), and compatibility with MPP multiprocessor platforms or workstation clusters is anticipated
Broto, K.
1999-04-01
The access to a reliable image of the subsurface requires a kinematically correct velocity depth model.Reflection tomography allows to meet this requirement if a complete and coherent pre-stack kinematic database can be provided. However, in case of complex sub-surfaces, wave propagation may lead to hardly interpretable seismic events in the time data. The SMART method is a sequential method that relies on reflection tomography for updating the velocity model and on the pre-stack depth migrated domain for extracting kinematic information that is not readily accessible in the time domain. For determining 3-D subsurface velocity models in case of complex structures, we propose the seriated SMART 2-D method as an alternative to the currently inconceivable SMART 3-D method. In order to extract kinematic information from a 3-D pre-stack data set, we combine detours through the 2-D pre-stack depth domain for a number of selected lines of the studied 3-D survey and 3-D reflection tomography for updating the velocity model. The travel-times from the SMART method being independent of the velocity model used for passing through the pre-stack depth migrated domain, the access to 3-D travel-times is ensured, even if they have been obtained via a 2-D domain. Besides, we propose to build a kinematical guide for ensuring the coherency of the seriated 2-D pre-stack depth interpretations and the access to a complete 3-D pre-stack kinematic database when dealing with structures associated with 3-D wave propagation. We opt for a blocky representation of the velocity model in order to be able to cope with complex structures. This representation leads us to define specific methodological rules for carrying out the different steps of the seriated SMART 2-D method. We also define strategies, built from the analysis of first inversion results, for an efficient application of reflection tomography. Besides, we discuss the problem of uncertainties to be assigned to travel-times obtained
The linear Boltzmann transport equation (BTE) is an integro-differential equation arising in deterministic models of neutral and charged particle transport. In slab (one-dimensional Cartesian) geometry and certain higher-dimensional cases, Diffusion Synthetic Acceleration (DSA) is known to be an effective algorithm for the iterative solution of the discretized BTE. Fourier and asymptotic analyses have been applied to various idealizations (e.g., problems on infinite domains with constant coefficients) to obtain sharp bounds on the convergence rate of DSA in such cases. While DSA has been shown to be a highly effective acceleration (or preconditioning) technique in one-dimensional problems, it has been observed to be less effective in higher dimensions. This is due in part to the expense of solving the related diffusion linear system. We investigate here the effectiveness of a parallel semicoarsening multigrid (SMG) solution approach to DSA preconditioning in several three dimensional problems. In particular, we consider the algorithmic and implementation scalability of a parallel SMG-DSA preconditioner on several types of test problems
Parallel unstructured mesh optimisation for 3D radiation transport and fluids modelling
In this paper we describe the theory and application of a parallel mesh optimisation procedure to obtain self-adapting finite element solutions on unstructured tetrahedral grids. The optimisation procedure adapts the tetrahedral mesh to the solution of a radiation transport or fluid flow problem without sacrificing the integrity of the boundary (geometry), or internal boundaries (regions) of the domain. The objective is to obtain a mesh which has both a uniform interpolation error in any direction and the element shapes are of good quality. This is accomplished with use of a non-Euclidean (anisotropic) metric which is related to the Hessian of the solution field. Appropriate scaling of the metric enables the resolution of multi-scale phenomena as encountered in transient incompressible fluids and multigroup transport calculations. The resulting metric is used to calculate element size and shape quality. The mesh optimisation method is based on a series of mesh connectivity and node position searches of the landscape defining mesh quality which is gauged by a functional. The mesh modification thus fits the solution field(s) in an optimal manner. The parallel mesh optimisation/adaptivity procedure presented in this paper is of general applicability. We illustrate this by applying it to a transient CFD (computational fluid dynamics) problem. Incompressible flow past a cylinder at moderate Reynolds numbers is modelled to demonstrate that the mesh can follow transient flow features. (authors)
Hybrid shared/distributed parallelism for 3D characteristics transport solvers
In this paper, we will present a new hybrid parallel model for solving large-scale 3-dimensional neutron transport problems used in nuclear reactor simulations. Large heterogeneous reactor problems, like the ones that occurs when simulating Candu cores, have remained computationally intensive and impractical for routine applications on single-node or even vector computers. Based on the characteristics method, this new model is designed to solve the transport equation after distributing the calculation load on a network of shared memory multi-processors. The tracks are either generated on the fly at each characteristics sweep or stored in sequential files. The load balancing is taken into account by estimating the calculation load of tracks and by distributing batches of uniform load on each node of the network. Moreover, the communication overhead can be predicted after benchmarking the latency and bandwidth using appropriate network test suite. These models are useful for predicting the performance of the parallel applications and to analyze the scalability of the parallel systems. (authors)
Depletion methodology in the 3-D whole core transport code DeCART
Three dimensional whole-core transport code DeCART has been developed to include a characteristics of the numerical reactor to replace partly the experiment. This code adopts the deterministic method in simulating the neutron behavior with the least assumption and approximation. This neutronic code is also coupled with the thermal hydraulic code CFD and the thermo mechanical code to simulate the combined effects. Depletion module has been implemented in DeCART code to predict the depleted composition in the fuel. The exponential matrix method of ORIGEN-2 has been used for the depletion calculation. The library of including decay constants, yield matrix and others has been used and greatly simplified for the calculation efficiency. This report summarizes the theoretical backgrounds and includes the verification of the depletion module in DeCART by performing the benchmark calculations
Simmons, Gary G.; Howett, Carly J. A.; Young, Leslie A.; Spencer, John R.
2015-11-01
In the last few decades, thermal data from the Galileo and Cassini spacecraft have detected various anomalies on Jovian and Saturnian satellites, including the thermally anomalous “PacMan” regions on Mimas and Tethys and the Pwyll anomaly on Europa (Howett et al. 2011, Howett et al. 2012, Spencer et al. 1999). Yet, the peculiarities of some of these anomalies, like the weak detection of the “PacMan” anomalies on Rhea and Dione and the low thermal inertia values of the widespread anomalies on equatorial Europa, are subjects for on-going research (Howett et al. 2014, Rathbun et al. 2010). Further, analysis and review of all the data both Galileo and Cassini took of these worlds will provide information of the thermal inertia and albedos of their surfaces, perhaps highlighting potential targets of interest for future Jovian and Saturnian system missions. Many previous works have used a thermophysical model for airless planets developed by Spencer (1990). However, the Three Dimensional Volatile-Transport (VT3D) model proposed by Young (2012) is able to predict surface temperatures in significantly faster computation time, incorporating seasonal and diurnal insolation variations. This work is the first step in an ongoing investigation, which will use VT3D’s capabilities to reanalyze Galileo and Cassini data. VT3D, which has already been used to analyze volatile transport on Pluto, is validated by comparing its results to that of the Spencer thermal model. We will also present our initial results using VT3D to reanalyze the thermophysical properties of the PacMan anomaly previous discovered on Mimas by Howett et al. (2011), using temperature constraints of diurnal data from Cassini/CIRS. VT3D is expected to be an efficient tool in identifying new thermal anomalies in future Saturnian and Jovian missions.Bibliography:C.J.A. Howett et al. (2011), Icarus 216, 221.C.J.A. Howett et al. (2012), Icarus 221, 1084.C.J.A. Howett et al. (2014), Icarus 241, 239.J
OMEGA, Subcritical and Critical Neutron Transport in General 3-D Geometry by Monte-Carlo
1 - Description of problem or function: OMEGA is a Monte Carlo code for the solution of the stationary neutron transport equation with k-eff as the Eigenvalue. A three-dimensional geometry is permitted consisting of a very general arrangement of three basic shapes (columns with circular, rectangular, or hexagonal cross section with a finite height and different material layers along their axes). The main restriction is that all the basic shapes must have parallel axes. Most real arrangements of fissile material inside and outside a reactor (e.g., in a fuel storage or transport container) can be described without approximation. The main field of application is the estimation of criticality safety. Many years of experience and comparison with reference cases have shown that the code together with the built-in cross section libraries gives reliable results. The following results can be calculated: - the effective multiplication factor k-eff; - the flux distribution; - reaction rates; - spatially and energetically condensed cross sections for later use in a subsequent OMEGA run. A running job may be interrupted and continued later, possibly with an increased number of batches for an improved statistical accuracy. The geometry as well as the k-eff results may be visualized. The use of the code is demonstrated by many illustrating examples. 2 - Method of solution: The Monte Carlo method is used with neutrons starting from an initial source distribution. The histories of a generation (or batch) of neutrons are followed from collision to collision until the histories are terminated by capture, fission, or leakage. For the solution of the Eigenvalue problem, the starting positions of the neutrons for a given generation are determined by the fission points of the preceding generation. The summation of the results starts only after some initial generations when the spatial part of the fission source has converged. At present the code uses the BNAB-78 subgroup library of the
Doppler effects on 3-D non-LTE radiation transport and emission spectra.
Giuliani, J. L. (Naval Research Laboratory, Washington, DC); Davis, J. (Naval Research Laboratory, Washington, DC); DasGupta, A. (Naval Research Laboratory, Washington, DC); Apruzese, John P. (Naval Research Laboratory, Washington, DC); Jennings, Christopher A.; Clark, R. W. (Naval Research Laboratory, Washington, DC); Ampleford, David J.; Bailey, James E.; Thornhill, Joseph W. (Naval Research Laboratory, Washington, DC); Cuneo, Michael Edward; Rochau, Gregory Alan; Coverdale, Christine Anne; Jones, Brent Manley; Hansen, Stephanie B.
2010-10-01
Spatially and temporally resolved X-ray emission lines contain information about temperatures, densities, velocities, and the gradients in a plasma. Extracting this information from optically thick lines emitted from complex ions in dynamic, three-dimensional, non-LTE plasmas requires self-consistent accounting for both non-LTE atomic physics and non-local radiative transfer. We present a brief description of a hybrid-structure spectroscopic atomic model coupled to an iterative tabular on-the-spot treatment of radiative transfer that can be applied to plasmas of arbitrary material composition, conditions, and geometries. The effects of Doppler line shifts on the self-consistent radiative transfer within the plasma and the emergent emission and absorption spectra are included in the model. Sample calculations for a two-level atom in a uniform cylindrical plasma are given, showing reasonable agreement with more sophisticated transport models and illustrating the potential complexity - or richness - of radially resolved emission lines from an imploding cylindrical plasma. Also presented is a comparison of modeled L- and K-shell spectra to temporally and radially resolved emission data from a Cu:Ni plasma. Finally, some shortcomings of the model and possible paths for improvement are discussed.
Doppler effects on 3-D non-LTE radiation transport and emission spectra
Spatially and temporally resolved X-ray emission lines contain information about temperatures, densities, velocities, and the gradients in a plasma. Extracting this information from optically thick lines emitted from complex ions in dynamic, three-dimensional, non-LTE plasmas requires self-consistent accounting for both non-LTE atomic physics and non-local radiative transfer. We present a brief description of a hybrid-structure spectroscopic atomic model coupled to an iterative tabular on-the-spot treatment of radiative transfer that can be applied to plasmas of arbitrary material composition, conditions, and geometries. The effects of Doppler line shifts on the self-consistent radiative transfer within the plasma and the emergent emission and absorption spectra are included in the model. Sample calculations for a two-level atom in a uniform cylindrical plasma are given, showing reasonable agreement with more sophisticated transport models and illustrating the potential complexity - or richness - of radially resolved emission lines from an imploding cylindrical plasma. Also presented is a comparison of modeled L- and K-shell spectra to temporally and radially resolved emission data from a Cu:Ni plasma. Finally, some shortcomings of the model and possible paths for improvement are discussed.
Le prix du transport : quels impacts sur le comportement des utilisateurs ?
MADRE,JL
2004-01-01
Cet article évoque les problèmes soulevés par l'augmentation du prix du carburant et des transports en commun. Quel est l'impact de ces évolutions sur le budget et les comportements des usagers ? Et comment les maitriser ?
TIMOC-72, 3-D Time-Dependent Homogeneous or Inhomogeneous Neutron Transport by Monte-Carlo
1 - Nature of physical problem solved: TIMOC solves the energy and time dependent (or stationary) homogeneous or inhomogeneous neutron transport equation in three-dimensional geometries. The program can treat all commonly used scattering kernels, such as absorption, fission, isotropic and anisotropic elastic scattering, level excitation, the evaporation model, and the energy transfer matrix model, which includes (n,2n) reactions. The exchangeable geometry routines consist at present of (a) periodical multilayer slab, spherical and cylindrical lattices, (b) an elaborate three-dimensional cylindrical geometry which allows all kinds of subdivisions, (c) the very flexible O5R geometry routine which is able to describe any body combinations with surfaces of second order. The program samples the stationary or time-energy-region dependent fluxes as well as the transmission ratios between geometrical regions and the following integral quantities or eigenvalues, the leakage rate, the slowing down density, the production to source ratio, the multiplication factor based on flux and collision estimator, the mean production time, the mean destruction time, time distribution of production and destruction, the fission rates, the energy dependent absorption rates, the energy deposition due to elastic scattering for the different geometrical regions. 2 - Method of solution: TIMOC is a Monte Carlo program and uses several, partially optional variance reducing techniques, such as the method of expected values (weight factor), Russian roulette, the method of fractional generated neutrons, double sampling, semi-systematic sampling and the method of expected leakage probability. Within the neutron lifetime a discrete energy value is given after each collision process. The nuclear data input is however done by group averaged cross sections. The program can generate the neutron fluxes either resulting from an external source or in the form of fundamental mode distributions by a special
TDTORT: Time-Dependent, 3-D, Discrete Ordinates, Neutron Transport Code System with Delayed Neutrons
1 - Description of program or function: TDTORT solves the time-dependent, three-dimensional neutron transport equation with explicit representation of delayed neutrons to estimate the fission yield from fissionable material transients. This release includes a modified version of TORT from the C00650MFMWS01 DOORS3.1 code package plus the time-dependent TDTORT code. GIP is also included for cross-section preparation. TORT calculates the flux or fluence of particles due to particles incident upon the system from extraneous sources or generated internally as a result of interaction with the system in two- or three-dimensional geometric systems. The principle application is to the deep-penetration transport of neutrons and photons. Reactor eigenvalue problems can also be solved. Numerous printed edits of the results are available, and results can be transferred to output files for subsequent analysis. TDTORT reads ANISN-format cross-section libraries, which are not included in the package. Users may choose from several available in RSICC's data library collection which can be identified by the keyword 'ANISN FORMAT'. 2 - Methods:The time-dependent spatial flux is expressed as a product of a space-, energy-, and angle-dependent shape function, which is usually slowly varying in time and a purely time-dependent amplitude function. The shape equation is solved for the shape using TORT; and the result is used to calculate the point kinetics parameters (e.g., reactivity) by using their inner product definitions, which are then used to solve the time-dependent amplitude and precursor equations. The amplitude function is calculated by solving the kinetics equations using the LSODE solver. When a new shape calculation is needed, the flux is calculated using the newly computed amplitude function. The Boltzmann transport equation is solved using the method of discrete ordinates to treat the directional variable and weighted finite-difference methods, in addition to Linear Nodal
Lee, Gang-Young; Han, A-Reum; Kim, Taewan; Lee, Hae Rang; Oh, Joon Hak; Park, Taiho
2016-05-18
To achieve extremely high planarity and processability simultaneously, we have newly designed and synthesized copolymers composed of donor units of 2,2'-(2,5-dialkoxy-1,4-phenylene)dithieno[3,2-b]thiophene (TT-P-TT) and acceptor units of diketopyrrolopyrrole (DPP). These copolymers consist of a highly planar backbone due to intramolecular interactions. We have systematically investigated the effects of intermolecular interactions by controlling the side chain bulkiness on the polymer thin-film morphologies, packing structures, and charge transport. The thin-film microstructures of the copolymers are found to be critically dependent upon subtle changes in the intermolecular interactions, and charge transport dynamics of the copolymer based field-effect transistors (FETs) has been investigated by in-depth structure-property relationship study. Although the size of the fibrillar structures increases as the bulkiness of the side chains in the copolymer increases, the copolymer with the smallest side chain shows remarkably high charge carrier mobility. Our findings reveal the requirement for forming efficient 3-D charge transport pathway and highlight the importance of the molecular packing and interdomain connectivity, rather than the crystalline domain size. The results obtained herein demonstrate the importance of tailoring the side chain bulkiness and provide new insights into the molecular design for high-performance polymer semiconductors. PMID:27117671
Prix du pétrole, coûts de transport et mondialisation
Nina Kousnetzoff; Daniel Mirza; Habib Zitouna
2008-01-01
Des données détaillées permettent d'observer sur une trentaine d'années l'évolution des coûts de transport des marchandises importées par les Etats-Unis. Des tendances claires se dessinent, mais sans que le lien avec le prix du pétrole, composante importante de ces coûts, soit toujours très visible. Seule l'analyse économétrique peut révéler l'impact du prix du pétrole sur le choix du mode de transport, sur les prix des produits importés et sur le partage du marché entre pays fournisseurs. Ce...
Bergmann, Ryan
Graphics processing units, or GPUs, have gradually increased in computational power from the small, job-specific boards of the early 1990s to the programmable powerhouses of today. Compared to more common central processing units, or CPUs, GPUs have a higher aggregate memory bandwidth, much higher floating-point operations per second (FLOPS), and lower energy consumption per FLOP. Because one of the main obstacles in exascale computing is power consumption, many new supercomputing platforms are gaining much of their computational capacity by incorporating GPUs into their compute nodes. Since CPU-optimized parallel algorithms are not directly portable to GPU architectures (or at least not without losing substantial performance), transport codes need to be rewritten to execute efficiently on GPUs. Unless this is done, reactor simulations cannot take full advantage of these new supercomputers. WARP, which can stand for ``Weaving All the Random Particles,'' is a three-dimensional (3D) continuous energy Monte Carlo neutron transport code developed in this work as to efficiently implement a continuous energy Monte Carlo neutron transport algorithm on a GPU. WARP accelerates Monte Carlo simulations while preserving the benefits of using the Monte Carlo Method, namely, very few physical and geometrical simplifications. WARP is able to calculate multiplication factors, flux tallies, and fission source distributions for time-independent problems, and can run in both criticality or fixed source modes. WARP can transport neutrons in unrestricted arrangements of parallelepipeds, hexagonal prisms, cylinders, and spheres. WARP uses an event-based algorithm, but with some important differences. Moving data is expensive, so WARP uses a remapping vector of pointer/index pairs to direct GPU threads to the data they need to access. The remapping vector is sorted by reaction type after every transport iteration using a high-efficiency parallel radix sort, which serves to keep the
Vannuccini, Elisa; Paccagnini, Eugenio; Cantele, Francesca; Gentile, Mariangela; Dini, Daniele; Fino, Federica; Diener, Dennis; Mencarelli, Caterina; Lupetti, Pietro
2016-05-15
Intraflagellar transport (IFT) is responsible for the bidirectional trafficking of molecular components required for the elongation and maintenance of eukaryotic cilia and flagella. Cargo is transported by IFT 'trains', linear rows of multiprotein particles moved by molecular motors along the axonemal doublets. We have previously described two structurally distinct categories of 'long' and 'short' trains. Here, we analyse the relative number of these trains throughout flagellar regeneration and show that long trains are most abundant at the beginning of flagellar growth whereas short trains gradually increase in number as flagella elongate. These observations are incompatible with the previous hypothesis that short trains are derived solely from the reorganization of long trains at the flagellar tip. We demonstrate with electron tomography the existence of two distinct ultrastructural organizations for the short trains, we name these 'narrow' and 'wide', and provide the first 3D model of the narrow short trains. These trains are characterized by tri-lobed units, which repeat longitudinally every 16 nm and contact protofilament 7 of the B-tubule. Functional implications of the new structural evidence are discussed. PMID:27044756
Rona, Michael; Gasser, Guy; Negev, Ido; Pankratov, Irena; Elhanany, Sara; Lev, Ovadia; Gvirtzman, Haim
2014-05-01
Wastewater recharge facilities are often used as a final water treatment before the discharge to the sea or before water reclamation. These facilities are often located in active aquifers that supply drinking water. Thus, leakage from the water recharge facility and gradual expansion of the underground wastewater plume are of considerable health concern. Hydrological modeling of water recharge systems are widely used as operational and predictive tools. These models rely on distributed water head monitoring and at least one chemical or physical tracer to model solutes' transport. Refractory micropollutants have proven useful in qualitative identification of pollution leakages and for quantification of pollution to a specific site near water recharge facilities. However, their usefulness as tracers for hydrological modeling is still questionable. In this article, we describe a long term, 3-D hydraulic model of a large-scale wastewater effluents recharge system in which a combination of chloride and a refractory micropollutant, carbamazepine is used to trace the solute transport. The combination of the two tracers provides the model with the benefits of the high specificity of the carbamazepine and the extensive historic data base that is available for chloride. The model predicts westward expansion of the pollution plume, whereas a standing front is formed at the east. These trends can be confirmed by the time trace of the carbamazepine concentrations at specific locations. We show that the combination of two tracers accounts better (at least at some locations) for the evolution of the pollution plume than a model based on chloride or carbamazepine alone.
Wehrer, Markus; Slater, Lee
2015-04-01
flow fraction was observed to be independent of precipitation rate. This suggests the presence of a fingering process driven by textural heterogeneities. As a consequence, preferential transport of the conservative and the reactive tracer also occurred. We found that 3D ERT can serve to quantitatively characterize shape measures of both tracer breakthroughs and water content dynamics. In particular, shape measures influenced by the advective propagation of the tracer peak, like mean velocity and normalized first central moment, are highly correlated between ERT data and validation data (consisting of tracer measurements in seepage water samples). Using shape measures proved to be advantageous over interpretation of ERT data with spatially uncertain petrophysical functions for the characterization of heterogeneous flow and transport. Consequently, for future applications of ERT in soil hydrological modeling, the use of temporal moments is recommended.
1 - Description of program or function: PARTISN (Parallel, Time-Dependent SN) is the evolutionary successor to CCC-0547/DANTSYS. User input and cross section formats are very similar to that of DANTSYS. The linear Boltzmann transport equation is solved for neutral particles using the deterministic (SN) method. Both the static (fixed source or eigenvalue) and time-dependent forms of the transport equation are solved in forward or adjoint mode. Vacuum, reflective, periodic, white, or inhomogeneous boundary conditions are solved. General anisotropic scattering and inhomogeneous sources are permitted. PARTISN solves the transport equation on orthogonal (single level or block-structured AMR) grids in 1-D (slab, two-angle slab, cylindrical, or spherical), 2-D (X-Y, R-Z, or R-T) and 3-D (X-Y-Z or R-Z-T) geometries. 2 - Methods:PARTISN numerically solves the multigroup form of the neutral-particle Boltzmann transport equation. The discrete-ordinates form of approximation is used for treating the angular variation of the particle distribution. For curvilinear geometries, diamond differencing is used for angular discretization. The spatial discretizations may be either low-order (diamond difference or Adaptive Weighted Diamond Difference (AWDD)) or higher-order (linear discontinuous or exponential discontinuous). Negative fluxes are eliminated by a local set-to-zero-and-correct algorithm for the diamond case (DD/STZ). Time differencing is Crank-Nicholson (diamond), also with a set-to-zero fix-up scheme. Both inner and outer iterations can be accelerated using the diffusion synthetic acceleration method, or transport synthetic acceleration can be used to accelerate the inner iterations. The diffusion solver uses either the conjugate gradient or multigrid method. Chebyshev acceleration of the fission source is used. The angular source terms may be treated either via standard PN expansions or Galerkin scattering. An option is provided for strictly positive scattering sources
LUO Kaiyu; LI Boquan; ZHANG Huanyan
2008-01-01
Different three-dimension (3D) nanotetrapods,containing club-like nanocrystals,nanotetrapods and four-foot-like nanocrystals were synthesized from Zinc sheet via CO2 laser irradiation and coaxially transporting O2.Different nanoproducts were fabricated by changing the content of oxygen in the experiment.The morphologies,components,phase structures and optical properties of the products were investigated by a field-emission scanning electron microscopy,an X-ray diffraction,an energy dispersed X-ray spectrometer and a photoluminescence spectroscope.The X-ray diffraction spectra were obtained on a Rigaku D/max 2500PC diffractometer.The experimental results reveal that high quality ZnO nanotetrapods can be fabricated on the special parameters,and growth of ZnO nanotetrapods depends on Vapour-Liquid-Solid(VLS) model,and the content of oxygen in the gas,namely,oxygen partial pressure is one of main factors to control morphologies and optical properties of ZnO nanotetrapods;these advantages above are important for realization of optoelectronic devices.
Wu, Dongwei
In recent years, Mainland China, and in particular the industrial hotbed of the Pearl River Delta (PRD) has experienced an increasingly serious problem of high concentrations of airborne particulate matter. Following the tightening-up of China's air quality policies in recent years, and with especially fine particles now added to a new air quality objective, the identification of major source regions and major types of pollutants has become critically important. In this study, a source-oriented method (Particulate Source Apportionment Technology: PSAT) implemented in 3-D Comprehensive Air Quality Model (CAMx), has been applied to analyze how different emission activities impact fine particle concentration in the PRD region. By using this method, a detailed source region and emission category contribution matrix is derived for all regions within the Hong Kong/PRD region. Source appointment results shows that, in summer and spring time, emissions inside PRD region are the major fine particle sources, contribution 70.7% (11.2 mug/m3) and 52.5% (13.1 mug/m3) to the total figure. Super-regional transports are found to be significant in autumn and winter, contribution 58.5% (20.2 mug/m3) and 64.6% (27.8 mug/m3) of the total fine particles in PRD and Hong Kong region. Another important cause of high PM levels has been the transport of fine particles between cities within the PRD region, with three different regions selected for detailed analysis. Results show that mobile vehicle and industry emission are the two major sources for fine particles. Meanwhile, over the same period in Hong Kong, marine proved to be another very significant source of particle pollutant in addition to the significant impact from motor vehicle. Results show that for the Hong Kong/PRD region local reduction of mobile sources and collaboration between different areas could have succeeded in alleviating the air pollution problem.
1 - Nature of physical problem solved: The function of the AIRTRANS system is to calculate by Monte Carlo methods the radiation field produced by neutron and/or gamma-ray sources which are located in the atmosphere. The radiation field is expressed as the time - and energy-dependent flux at a maximum of 50 point detectors in the atmosphere. The system calculates un-collided fluxes analytically and collided fluxes by the 'once-more collided' flux-at-a-point technique. Energy-dependent response functions can be applied to the fluxes to obtain desired flux functionals, such as doses, at the detector point. AIRTRANS also can be employed to generate sources of secondary gamma radiation. 2 - Method of solution - Neutron interactions treated in the calculational scheme include elastic (isotropic and anisotropic) scattering, inelastic (discrete level and continuum) scattering, and absorption. Charged particle reactions, e.g, (n,p) are treated as absorptions. A built-in kernel option can be employed to take neutrons from the 150 keV to thermal energy, thus eliminating the need for particle tracking in this energy range. Another option used in conjunction with the neutron transport problem creates an 'interaction tape' which describes all the collision events that can lead to the production of secondary gamma-rays. This interaction tape subsequently can be used to generate a source of secondary gamma rays. The gamma-ray interactions considered include Compton scattering, pair production, and the photoelectric effect; the latter two processes are treated as absorption events. Incorporated in the system is an option to use a simple importance sampling technique for detectors that are many mean free paths from the source. In essence, particles which fly far from the source are split into fragments, the degree of fragmentation being proportional to the penetration distance from the source. Each fragment is tracked separately, thus increasing the percentage of computer time spent
Bergmann, Ryan
Graphics processing units, or GPUs, have gradually increased in computational power from the small, job-specific boards of the early 1990s to the programmable powerhouses of today. Compared to more common central processing units, or CPUs, GPUs have a higher aggregate memory bandwidth, much higher floating-point operations per second (FLOPS), and lower energy consumption per FLOP. Because one of the main obstacles in exascale computing is power consumption, many new supercomputing platforms are gaining much of their computational capacity by incorporating GPUs into their compute nodes. Since CPU-optimized parallel algorithms are not directly portable to GPU architectures (or at least not without losing substantial performance), transport codes need to be rewritten to execute efficiently on GPUs. Unless this is done, reactor simulations cannot take full advantage of these new supercomputers. WARP, which can stand for ``Weaving All the Random Particles,'' is a three-dimensional (3D) continuous energy Monte Carlo neutron transport code developed in this work as to efficiently implement a continuous energy Monte Carlo neutron transport algorithm on a GPU. WARP accelerates Monte Carlo simulations while preserving the benefits of using the Monte Carlo Method, namely, very few physical and geometrical simplifications. WARP is able to calculate multiplication factors, flux tallies, and fission source distributions for time-independent problems, and can run in both criticality or fixed source modes. WARP can transport neutrons in unrestricted arrangements of parallelepipeds, hexagonal prisms, cylinders, and spheres. WARP uses an event-based algorithm, but with some important differences. Moving data is expensive, so WARP uses a remapping vector of pointer/index pairs to direct GPU threads to the data they need to access. The remapping vector is sorted by reaction type after every transport iteration using a high-efficiency parallel radix sort, which serves to keep the
Dorval, C. [Commissariat a l' Energie Atomique, 75 - Paris (France)
1966-05-01
In studying the competitiveness of a nuclear merchant vessel, economic assessments in terms of figures were discarded in favor of a simplified model, which gives a clearer idea of the mechanism of the comparison between alternative vessels and the particular influence of each parameter. An expression is formulated for the unit cost per ton carried over a given distance as a function of the variables (speed and deadweight tonnage) and is used to determine the optima for conventional and nuclear vessels. To represent the freight market involved in the optimization studies, and thus in the competitiveness computation, two cases are taken into account: the tonnage to be carried annually is limited, and the tonnage to be carried annually is not limited. In both cases the optima are calculated and compared for a conventional and a nuclear vessel. Competitiveness curves are plotted as a function of the ratios of nuclear and conventional fuel costs and nuclear and conventional marginal power costs. These curves express the limiting values of the above two ratios for which the transport costs of the nuclear and conventional vessels are equal. The competitiveness curves vary considerably according to the hypothesis adopted for the freight market and the limit of tonnage carried annually. (author) [French] Pour etudier la competitivite du navire marchand nucleaire, plutot que de nous livrer a des evaluations economiques chiffrees, discutables dans l'etat actuel des etudes, nous utilisons un modele simplifie permettant de mieux saisir le mecanisme de la comparaison des navires et l'influence particuliere de chaque parametre. Nous etablissons une expression du cout unitaire de la tonne transportee sur un parcours donne en fonction des variables vitesse et port en lourd. Et nous l'utilisons pour determiner les optima des navires classiques et nucleaires. Pour representer le marche du fret qui intervient dans les etudes d'optimisation, et donc dans la
Toorman, E.A.; Widera, P.; Heredia, M; Lacor, C
2008-01-01
Currently used 3D numerical sediment transport models still fail to make good quantitative predictions. To a great extent, this can be attributed to the inadequate description of physical processes which occur at the subgrid scale level. From flume experiments it is known that particle-turbulence interactions near the bed significantly change the effective roughness experienced by the overlying water column. This results in different transport rates if not accounted for.From a theoretical per...
G. W. Mann
2012-01-01
Full Text Available A global modal aerosol microphysics module (GLOMAP-mode is evaluated and improved by comparing against a sectional version (GLOMAP-bin and observations in the same 3-D global offline chemistry transport model. With both schemes, the model captures the main features of the global particle size distribution, with sub-micron aerosol approximately unimodal in continental regions and bi-modal in marine regions. Initial bin-mode comparisons showed that various size distribution parameter settings (mode widths and inter-modal separation sizes resulted in clear biases compared to the sectional scheme. By adjusting these parameters in the modal scheme, much better agreement is achieved against the bin scheme and observations. Surface mass of sulphate, sea-salt, black carbon (BC and organic carbon (OC are, on the annual mean, within 25 % in the two schemes in nearly all regions. On the annual mean, surface level concentrations of condensation nuclei (CN, cloud condensation nuclei (CCN, surface area density and condensation sink also compare within 25 % in most regions. However, marine CCN concentrations between 30° N and 30° S are systematically higher in the modal scheme, by 25–60 %, which we attribute to differences in size-resolved particle growth or cloud-processing. Larger differences also exist in regions or seasons dominated by biomass burning and in free-troposphere and high-latitude regions. Indeed, in the free-troposphere, GLOMAP-mode BC is a factor 2–4 higher than GLOMAP-bin, likely due to differences in size-resolved scavenging. Nevertheless, in most parts of the atmosphere, we conclude that bin-mode differences are much less than model-observation differences, although some processes are missing in these runs which may pose a bigger challenge to modal schemes (e.g. boundary layer nucleation, ultra-fine sea-spray. The findings here underline the need for a spectrum of complexity in global models, with size-resolved aerosol properties
G. W. Mann
2012-05-01
Full Text Available In the most advanced aerosol-climate models it is common to represent the aerosol particle size distribution in terms of several log-normal modes. This approach, motivated by computational efficiency, makes assumptions about the shape of the particle distribution that may not always capture the properties of global aerosol. Here, a global modal aerosol microphysics module (GLOMAP-mode is evaluated and improved by comparing against a sectional version (GLOMAP-bin and observations in the same 3-D global offline chemistry transport model. With both schemes, the model captures the main features of the global particle size distribution, with sub-micron aerosol approximately unimodal in continental regions and bi-modal in marine regions. Initial bin-mode comparisons showed that the current values for two size distribution parameter settings in the modal scheme (mode widths and inter-modal separation sizes resulted in clear biases compared to the sectional scheme. By adjusting these parameters in the modal scheme, much better agreement is achieved against the bin scheme and observations. Annual mean surface-level mass of sulphate, sea-salt, black carbon (BC and organic carbon (OC are within 25% in the two schemes in nearly all regions. Surface level concentrations of condensation nuclei (CN, cloud condensation nuclei (CCN, surface area density and condensation sink also compare within 25% in most regions. However, marine CCN concentrations between 30° N and 30° S are systematically 25–60% higher in the modal model, which we attribute to differences in size-resolved particle growth or cloud-processing. Larger differences also exist in regions or seasons dominated by biomass burning and in free-troposphere and high-latitude regions. Indeed, in the free-troposphere, GLOMAP-mode BC is a factor 2–4 higher than GLOMAP-bin, likely due to differences in size-resolved scavenging. Nevertheless, in most parts of the atmosphere, we conclude that bin
DuPontTM Debut®DuoActive (DPX-R3D76: A new product for optimized herbicide programs in beets
Helinski, Christian
2016-02-01
Full Text Available DuPontTM Debut®DuoActive (triflusulfuron-methyl 71 g/kg, Lenacil 714 g/kg is a new herbicide for the control of broadleaf weeds in fodder and sugar beets. The combination of a leave with a soil active ingredient controls successfully typical broadleaf weeds as well as hard to control weeds like volunteer oilseed rape (Brassica napus, knotweeds (Polygonum ssp., fool's parsley (Aethusa cynapium and cleavers (Galium aparine. Debut®DuoActive is an excellent partner for standard tankmixes based on the active ingredients Phen/-desmedipham, ethofumesate und metamitron. As part of a herbicide program Debut®DuoActive helps to improve significantly the efficiency of standard herbicide tankmixes and reduces the necessity of possible subsequent treatment. Registration is applied for use in fodder and sugar beet (BBCH 10-39 with a use rate of 210 g/ha (+ 0.1 % (v/v DuPontTM Trend®.
A current area of research interest in national security is to effectively and efficiently determine the contents of the many shipping containers that enter ports in the United States. This interest comes as a result of the 9/11 Commission Act passed by Congress in 2007 that requires 100% of inbound cargo to be scanned by 2012. It appears that this requirement will be achieved by 2012, but as of February of 2009 eighty percent of the 11.5 million inbound cargo containers were being scanned. The systems used today in all major U.S. ports to determine the presence of radioactive material within cargo containers are Radiation Portal Monitors (RPM). These devices generally exist in the form of a gate or series of gates that the containers can be driven through and scanned. The monitors are effective for determining the presence of radiation, but offer little more information about the particular source. This simple pass-fail system leads to many false alarms as many everyday items emit radiation including smoke detectors due to the Americium-241 source contained inside, bananas, milk, cocoa powder and lean beef due to the trace amounts of Potassium-40, and fire brick and kitty litter due to their high clay content which often contains traces of uranium and thorium. In addition, if an illuminating source is imposed on the boundary of the container, the contents of the container may become activated. These materials include steel, aluminum and many agricultural products. Current portal monitors also have not proven to be that effective at identifying natural or highly enriched uranium (HEU). In fact, the best available Advanced Spectroscopic Portal Monitors (ASP) are only capable of identifying bare HEU 70-88% of the time and masked HEU and depleted uranium (DU) only 53 percent of the time. Therefore, a better algorithm that uses more information collected from better detectors about the specific material distribution within the container is desired. The work reported
Couleurs et dorures du portail roman de Cluny III. Restitution en 3D d’une œuvre disparue
Juliette Rollier-Hanselmann
2010-10-01
Full Text Available La construction de l’ancienne abbaye Saint-Pierre-et-Saint-Paul de Cluny s’est échelonnée dans le temps, avec une première consécration du chevet en 1095, et une autre dédicace en 1130, correspondant vraisemblablement à une nouvelle étape d’avancement de la basilique romane.Le portail, qui s’ouvrait sur la nef centrale, daté entre 1100 et 1120, figure parmi les créations romanes de grande envergure qui nécessita des techniques exceptionnelles. Il mesurait 5,60 m de large et 3,25 m de hauteur,...
Exploitation de données AIS pour la cartographie du transport maritime
Damien Le Guyader; David Brosset; Françoise Gourmelon
2011-01-01
Cet article présente une méthodologie de caractérisation spatiale, temporelle et quantitative du transport maritime en rade de Brest (Bretagne, France), difficile à appréhender du fait de sa forte variabilité. Par la mobilisation d'une base d'informations spatio-temporelles issues de données AIS (Automatic Identification System) et le recours à des procédures d'analyse spatiale mises en œuvre au sein d'un SIG (Système d'Information Géographique), le trafic maritime quotidien de charge et de p...
Utilisation du transport en commun chez les immigrants
Heisz, Andrew; Schellenberg, Grant
2004-01-01
Dans cet article, on examine, a l'aide des donnees tirees des recensements de la population de 1996 et de 2001, la probabilite que les immigrants et les personnes nees au Canada utilisent le transport en commun. On discute egalement des repercussions sur les services de transport en commun.
One of the important issues regarding deterministic transport methods for whole core calculations is that homogenized techniques can introduce errors into results. On the other hand, with modern computation abilities, direct whole core heterogeneous calculations are becoming increasingly feasible. This report provides an analysis of the results obtained from a challenging benchmark on deterministic MOX fuel assembly transport calculations without spatial homogenization. A majority of the participants obtained solutions that were more than acceptable for typical reactor calculations. The report will be of particular interest to reactor physicists and transport code developers. (author)
L. A. Barrie
2007-03-01
Full Text Available Global transports and budgets of three PCBs were investigated with a 3-D dynamic model for semi-volatile persistent organic pollutants – GEM/POPs. Dominant pathways were identified for PCB transports in the atmosphere with a peak transport flux below 8 km and 14 km for gaseous and particulate PCB28, 4 km and 6 km for gaseous and particulate PCB180. The inter-continental transports of PCBs in the Northern Hemisphere (NH are dominated in the zonal direction with their route changes seasonally regulated by the variation of westerly jet. The transport pathways from Europe and North Atlantic to the Arctic contributed the most PCBs over there. Inter-hemispheric transports of PCBs originated from the regions of Europe, Asia and North America in three different flow-paths, accompanying with easterly jet, Asian monsoon winds and trade winds. PCBs from the Southern Hemisphere (SH could export into the NH. According to the PCB emissions of year 2000, Europe, North America and Asia are the three largest sources of the three PCBs, contributing to the global background concentrations in the atmosphere and soil and water. Globally, PCB28 in soil and water has become a comparable source to the anthropogenic emissions while heavier PCBs such as PCB153 and 180 are still transporting into soil and water. It is found that lighter PCBs have more long range transport potentials than their heavier counter-parts in the atmosphere.
Üpping, J.; Bielawny, A.; Lee, S.; Knez, M.; Carius, R.; Wehrspohn, R. B.
2009-08-01
The progress of 3D photonic intermediate reflectors for micromorph silicon tandem cells towards a first prototype cell is presented. Intermediate reflectors enhance the absorption of spectrally-selected light in the top cell and decrease the current mismatch between both junctions. A numerical method to predict filter properties for optimal current matching is presented. Our device is an inverted opal structure made of ZnO and fabricated using self-organized nanoparticles and atomic layer deposition for conformal coating. In particular, the influence of ZnO-doping and replicated cracks during drying of the opal is discussed with respect to conductivity and optical properties. A first prototype is compared to a state-of-the-art reference cell.
Carafa, R; Marinov, D; Dueri, S; Wollgast, J; Ligthart, J; Canuti, E; Viaroli, P; Zaldívar, J M
2006-10-01
Sacca di Goro is a shallow coastal microtidal lagoon with a surface area of 26 km2, and an average depth of about 1.5m. Fresh water pollutant loads from Po River branches and several drainage canals lead to anthropogenic eutrophication, frequent summer anoxia crises and chemical contamination. Such events not only affect the lagoon ecosystem but also cause serious economic losses, the lagoon being the second largest producer of clams in Italy. The present work aims at using a fate model coupled with COHERENS 3D hydrodynamic model to simulate and to explain the spatial distribution and temporal variations of s-triazines herbicides in the Sacca di Goro lagoon. The simulation results of spatial and temporal dynamic behaviour of atrazine, simazine and terbuthylazine have been compared with experimental data obtained during an annual monitoring programme. PMID:16643962
The new deterministic 3-D radiation transport code Multitrans: C5G7 MOX fuel assembly benchmark
The novel deterministic three-dimensional radiation transport code MultiTrans is based on combination of the advanced tree multigrid technique and the simplified P3 (SP3) radiation transport approximation. In the tree multigrid technique, an automatic mesh refinement is performed on material surfaces. The tree multigrid is generated directly from stereo-lithography (STL) files exported by computer-aided design (CAD) systems, thus allowing an easy interface for construction and upgrading of the geometry. The deterministic MultiTrans code allows fast solution of complicated three-dimensional transport problems in detail, offering a new tool for nuclear applications in reactor physics. In order to determine the feasibility of a new code, computational benchmarks need to be carried out. In this work, MultiTrans code is tested for a seven-group three-dimensional MOX fuel assembly transport benchmark without spatial homogenization (NEA C5G7 MOX). (author)
Etude du transport d'électrons Rapides pour la fusion par confinement inertiel
Touati, Michaël
2015-01-01
Un nouveau mod`ele r´eduit pour le transport de faisceaux d’´electrons relativistes dans des solide ou des plasma denses est propos´e. Il est bas´e sur la r´esolution des deux premiers moments angulaires de l’´equation cin´etique relativiste, compl´et´es par une relation de fermeture d´eduite du principe de maximisation de l’entropie angulaire de Minerbo. Le mod`ele prend en compte aussi bien les effets collectifs du transport avec les champs ´electromagn´etiques auto g´en´er´es que les effet...
The application and performance of ACMFD acceleration in 2D/3D full core MOC transport fuse method
It has been shown that the Analytic Coarse Mesh Finite Difference (ACMFD) method is very robust in nodal diffusion acceleration because of its rigorous derivation, and also should be applicable in core transport methods. In the past decade, the Method of Characteristics (MOC) was widely studied either in 2D or 2D/1D fuse cases with Coarse Mesh Finite Difference (CMFD). In this paper, the application of ACMFD in 2D or 2D/1D fuse MOC transport theory as an acceleration method is presented. Numerical result indicates that the performance of ACMFD is similar to CMFD. (author)
In safety assessments of underground radioactive waste repositories, understanding radionuclide fate in ecosystems is necessary to determine the impacts of potential releases. Here, the reliability of two mechanistic models (the compartmental K-model and the 3D dynamic D-model) in describing the fate of radionuclides released into a Baltic Sea bay is tested. Both are based on ecosystem models that simulate the cycling of organic matter (carbon). Radionuclide transfer is linked to adsorption and flows of carbon in food chains. Accumulation of Th-230, Cs-135, and Ni-59 in biological compartments was comparable between the models and site measurements despite differences in temporal resolution, biological state variables, and partition coefficients. Both models provided confidence limits for their modeled concentration ratios, an improvement over models that only estimate means. The D-model enables estimates at high spatio-temporal resolution. The K-model, being coarser but faster, allows estimates centuries ahead. Future developments could integrate the two models to take advantage of their respective strengths
Modeling of tungsten transport in the linear plasma device PSI-2 with the 3D Monte-Carlo code ERO
Marenkov, E.; Eksaeva, A.; Borodin, D.; Kirschner, A.; Laengner, M.; Kurnaev, V.; Kreter, A.; Coenen, J. W.; Rasinski, M.
2015-08-01
The ERO code was modified for modeling of plasma-surface interactions and impurities transport in the PSI-2 installation. Results of experiments on tungsten target irradiation with argon plasma were taken as a benchmark for the new version of the code. Spectroscopy data modeled with the code are in good agreement with experimental ones. Main factors contributing to observed discrepancies are discussed.
Bentzen, Thomas Ruby
2009-01-01
The paper presents results from an experimental and numerical study of flows and transport of primarily particle bound pollutants in highway wet detention ponds. The study presented here is part of a general investigation on road runoff and pollution in respect to wet detention ponds. The objecti...
Dimensionality-dependent charge transport in close-packed nanoparticle arrays: from 2D to 3D
Wang, Ying; Duan, Chao; Peng, Lianmao; Liao, Jianhui
2014-12-01
Charge transport properties in close-packed nanoparticle arrays with thickness crossing over from two dimensions to three dimensions have been studied. The dimensionality transition of nanoparticle arrays was realized by continually printing spatially well-defined nanoparticle monolayers on top of the device in situ. The evolution of charge transport properties depending on the dimensionality has been investigated in both the Efros-Shaklovskii variable-range-hopping (ES-VRH) (low temperature) regime and the sequential hopping (SH) (medium temperature) regime. We find that the energy barriers to transport decrease when the thickness of nanoparticle arrays increases from monolayer to multilayers, but start to level off at the thickness of 4-5 monolayers. The energy barriers are characterized by the coefficient βD at ES-VRH regime and the activation energy Ea at SH regime. Moreover, a turning point for the temperature coefficient of conductance was observed in multilayer nanoparticle arrays at high temperature, which is attributed to the increasing mobility with decreasing temperature of hopping transport in three dimensions.
Hartenstein, M. [TN International (groupe AREVA), 78 - Montigny-le-Bretonneux (France)
2011-01-15
After a presentation of the context of radioactive material transportation (types of transported materials, applicable constraints), the author describes the different kinds of packaging used during the different stages of the fuel cycle in the case of light water reactors: ore concentrates, UF{sub 4} and UF{sub 6}, low enriched uranium oxide, impoverished uranium oxide, plutonium oxide, new UO{sub 2} and MOX fuel assemblies, irradiated fuel assemblies aimed at processing-recycling, uranyl nitrate, warehousing of irradiated fuels before final storage, wastes (high, very low, low and medium activity). He briefly evokes packaging for the case of fast neutron or fusion reactors. He discusses the various aspects of packaging design: safety function, applicable constraints and tests, design and material choice with respect with various issues (criticality, confinement, biological protection, heat transfer, mechanical resistance and shock damping properties, radiolysis and thermolysis, interfaces with transportation installations and means). He describes how packaging is exploited: life cycle management, fabrication, exploitation, maintenance and spare parts, end of life, documentation. He addresses how transportation is organised by evoking transport means and modes, and transport commissioning
Defect chemistry and transport properties of BaxCe0.85M0.15O3-d
Wu, J.; Li, L. P.; Espinosa, W. T. P.; Haile, S. M.
2004-01-01
The site-incorporation mechanism of M3+ dopants into A2+B4+O3 perovskites controls the overall defect chemistry and thus their transport properties. For charge-balance reasons, incorporation onto the A2+-site would require the creation of negatively charged point defects (such as cation vacancies), whereas incorporation onto the B4+-site is accompanied by the generation of positively charged defects, typically oxygen vacancies. Oxygen-vacancy content, in turn, is relevant to proton-conducting...
Voss, Clifford I.; Provost, A.M.
2002-01-01
SUTRA (Saturated-Unsaturated Transport) is a computer program that simulates fluid movement and the transport of either energy or dissolved substances in a subsurface environment. This upgraded version of SUTRA adds the capability for three-dimensional simulation to the former code (Voss, 1984), which allowed only two-dimensional simulation. The code employs a two- or three-dimensional finite-element and finite-difference method to approximate the governing equations that describe the two interdependent processes that are simulated: 1) fluid density-dependent saturated or unsaturated ground-water flow; and 2) either (a) transport of a solute in the ground water, in which the solute may be subject to: equilibrium adsorption on the porous matrix, and both first-order and zero-order production or decay; or (b) transport of thermal energy in the ground water and solid matrix of the aquifer. SUTRA may also be used to simulate simpler subsets of the above processes. A flow-direction-dependent dispersion process for anisotropic media is also provided by the code and is introduced in this report. As the primary calculated result, SUTRA provides fluid pressures and either solute concentrations or temperatures, as they vary with time, everywhere in the simulated subsurface system. SUTRA flow simulation may be employed for two-dimensional (2D) areal, cross sectional and three-dimensional (3D) modeling of saturated ground-water flow systems, and for cross sectional and 3D modeling of unsaturated zone flow. Solute-transport simulation using SUTRA may be employed to model natural or man-induced chemical-species transport including processes of solute sorption, production, and decay. For example, it may be applied to analyze ground-water contaminant transport problems and aquifer restoration designs. In addition, solute-transport simulation with SUTRA may be used for modeling of variable-density leachate movement, and for cross sectional modeling of saltwater intrusion in
For the purpose of performing core calculations in hexagonal geometry with good accuracy, NSHEX has been developed. It has the following characteristics. Intra-node flux distribution is expressed by a second order polynomial series. Angular dependence of the flux is treated by the discrete ordinate method (Sn method). As the node-to-node coupling condition the continuity of each angular flux is used. Furthermore new treatments of transverse leakage are incorporated. In order to investigate the accuracy of NSHEX, it was applied to two FBR models, and the results were compared with the reference Monte Carlo method and other transport calculation ones. (author)
HAN,Xiao-Feng; LIU,Yu-Xiu; LIU,Ying; LAI,Lu-Hua; HUANG,Run-Qiu; WANG,Qing-Min
2007-01-01
The binding model of 3-(2-chloropyrid-5-ylmethylamino)-2-cyanoacrylate photosystem Ⅱ (PSⅡ) electron transport inhibitors with the D1 protein of PSⅡ was built. The high herbicidal activity of this kind of inhibitors was explained by docking studies: in addition to usual factors, the N atom on the pyridine ring could form an H-bond with the backbone amide of Phe265 on the D1 protein. 3D-QSAR analysis on sixteen 3-(2-chloropyrid-5-ylmethylamino)-2-cyanoacrylate compounds was performed using CoMFA method to explain the nature of interactions between the compounds and D1 protein. These studies may provide useful insights for designing new PSⅡ electron transport inhibitors.
Improved TORT solutions to the 3D transport codes suite of benchmarks exercise are presented in this study. Preliminary TORT solutions to this benchmark indicate that the majority of benchmark quantities for most benchmark cases are computed with good accuracy, and that accuracy improves with model refinement. However, TORT fails to compute accurate results for some benchmark cases with aspect ratios drastically different from 1, possibly due to ray effects. In this work, we employ the standard approach of splitting the solution to the transport equation into an uncollided flux and a fully collided flux via the code sequence GRTUNCL3D and TORT to mitigate ray effects. The results of this code sequence presented in this paper show that the accuracy of most benchmark cases improved substantially. Furthermore, the iterative convergence problems reported for the preliminary TORT solutions have been resolved by bringing the computational cells' aspect ratio closer to unity and, more importantly, by using 64-bit arithmetic precision in the calculation sequence. Results of this study are also reported
Rmili, W.; Vivet, N.; Chupin, S.; Le Bihan, T.; Le Quilliec, G.; Richard, C.
2016-04-01
As part of development of a new assembly technology to achieve bonding for an innovative silicon carbide (SiC) power device used in harsh environments, the aim of this study is to compare two silver sintering profiles and then to define the best candidate for die attach material for this new component. To achieve this goal, the solder joints have been characterized in terms of porosity by determination of the morphological characteristics of the material heterogeneities and estimating their thermal and electrical transport properties. The three dimensional (3D) microstructure of sintered silver samples has been reconstructed using a focused ion beam scanning electron microscope (FIB-SEM) tomography technique. The sample preparation and the experimental milling and imaging parameters have been optimized in order to obtain a high quality of 3D reconstruction. Volume fractions and volumetric connectivity of the individual phases (silver and voids) have been determined. Effective thermal and electrical conductivities of the samples and the tortuosity of the silver phase have been also evaluated by solving the diffusive transport equation.
When dealing with nuclear reactor calculation schemes, the need for 3D transport-based reference solutions is essential for validation and optimization purposes. As SN transport method may be considered promising with respect to comprehensive parallel computations, a 3D full PWR core benchmark was proposed to challenge the capabilities of the PENTRAN parallel SN code utilizing an IBM-BG/P computer. After a brief description of the benchmark, a parallel performance analysis is carried out, and shows that the parallelizable (Amdahl) fraction of PENTRAN is comprised between 0.994 ≤ f ≤ 0.996 for a number of BG/P nodes ranging from 17 to 1156. The associated speedup reaches a value greater than 200 with 1156 nodes. Using a best estimate model, PENTRAN results are then compared to Monte Carlo results rendered using the MCNP5 code. Good consistency is observed between the two methods (SN and Monte Carlo), with discrepancies less than 65 pcm for the keff, and less than 2.5% for the flux at the pincell level. (author)
The vanadium redox flow battery (VRFB) has emerged as a viable grid-scale energy storage technology that offers cost-effective energy storage solutions for renewable energy applications. In this paper, a novel methodology is introduced for modeling of the transport mechanisms of electrolyte flow, species and charge in the VRFB at the pore scale of the electrodes; that is, at the level where individual carbon fiber geometry and electrolyte flow are directly resolved. The detailed geometry of the electrode is obtained using X-ray computed tomography (XCT) and calibrated against experimentally determined pore-scale characteristics (e.g., pore and fiber diameter, porosity, and surface area). The processed XCT data is then used as geometry input for modeling of the electrochemical processes in the VRFB. The flow of electrolyte through the pore space is modeled using the lattice Boltzmann method (LBM) while the finite volume method (FVM) is used to solve the coupled species and charge transport and predict the performance of the VRFB under various conditions. An electrochemical model using the Butler–Volmer equations is used to provide species and charge coupling at the surfaces of the carbon fibers. Results are obtained for the cell potential distribution, as well as local concentration, overpotential and current density profiles under galvanostatic discharge conditions. The cell performance is investigated as a function of the electrolyte flow rate and external drawing current. The model developed here provides a useful tool for building the structure–property–performance relationship of VRFB electrodes.
Marcel Meury
Full Text Available Human heteromeric amino acid transporters (HATs are membrane protein complexes that facilitate the transport of specific amino acids across cell membranes. Loss of function or overexpression of these transporters is implicated in several human diseases such as renal aminoacidurias and cancer. HATs are composed of two subunits, a heavy and a light subunit, that are covalently connected by a disulphide bridge. Light subunits catalyse amino acid transport and consist of twelve transmembrane α-helix domains. Heavy subunits are type II membrane N-glycoproteins with a large extracellular domain and are involved in the trafficking of the complex to the plasma membrane. Structural information on HATs is scarce because of the difficulty in heterologous overexpression. Recently, we had a major breakthrough with the overexpression of a recombinant HAT, 4F2hc-LAT2, in the methylotrophic yeast Pichia pastoris. Microgram amounts of purified protein made possible the reconstruction of the first 3D map of a human HAT by negative-stain transmission electron microscopy. Here we report the important stabilization of purified human 4F2hc-LAT2 using a combination of two detergents, i.e., n-dodecyl-β-D-maltopyranoside and lauryl maltose neopentyl glycol, and cholesteryl hemisuccinate. The superior quality and stability of purified 4F2hc-LAT2 allowed the measurement of substrate binding by scintillation proximity assay. In addition, an improved 3D map of this HAT could be obtained. The detergent-induced stabilization of the purified human 4F2hc-LAT2 complex presented here paves the way towards its crystallization and structure determination at high-resolution, and thus the elucidation of the working mechanism of this important protein complex at the molecular level.
Exploitation de données AIS pour la cartographie du transport maritime
Damien Le Guyader
2011-12-01
Full Text Available Cet article présente une méthodologie de caractérisation spatiale, temporelle et quantitative du transport maritime en rade de Brest (Bretagne, France, difficile à appréhender du fait de sa forte variabilité. Par la mobilisation d'une base d'informations spatio-temporelles issues de données AIS (Automatic Identification System et le recours à des procédures d'analyse spatiale mises en œuvre au sein d'un SIG (Système d'Information Géographique, le trafic maritime quotidien de charge et de passagers est identifié, quantifié et cartographié pour une année.
Abdelkrim, Malek
2004-01-01
Dans le contexte de l'ingénierie du transport, ce travail est consacré à l'étude du comportement cyclique à long terme des infrastructures (voie ferrée, chaussées routières, ...). Ces dernières sont sujettes à des chargements de trafic qui provoquent des dégradations importantes (défauts de voies ferrées et orniérage des chaussées) ayant pour conséquence des problèmes d'exploitation, de confort et de sécurité des usagers. Les campagnes de maintenance étant coûteuses, il en résulte la nécessit...
Cullen, D E
1998-11-22
TART98 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo radiation transport code. This code can run on any modern computer. It is a complete system to assist you with input preparation, running Monte Carlo calculations, and analysis of output results. TART98 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART98 is distributed on CD. This CD contains on-line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART98 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART98 and its data files.
TART2000 is a coupled neutron-photon, 3 Dimensional, combinatorial geometry, time dependent Monte Carlo radiation transport code. This code can run on any modern computer. It is a complete system to assist you with input Preparation, running Monte Carlo calculations, and analysis of output results. TART2000 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared to other similar codes. Use of the entire system can save you a great deal of time and energy. TART2000 is distributed on CD. This CD contains on-line documentation for all codes included in the system, the codes configured to run on a variety of computers, and many example problems that you can use to familiarize yourself with the system. TART2000 completely supersedes all older versions of TART, and it is strongly recommended that users only use the most recent version of TART2000 and its data files
Lucas, Laurent; Loscos, Céline
2013-01-01
While 3D vision has existed for many years, the use of 3D cameras and video-based modeling by the film industry has induced an explosion of interest for 3D acquisition technology, 3D content and 3D displays. As such, 3D video has become one of the new technology trends of this century.The chapters in this book cover a large spectrum of areas connected to 3D video, which are presented both theoretically and technologically, while taking into account both physiological and perceptual aspects. Stepping away from traditional 3D vision, the authors, all currently involved in these areas, provide th
Beane, Andy
2012-01-01
The essential fundamentals of 3D animation for aspiring 3D artists 3D is everywhere--video games, movie and television special effects, mobile devices, etc. Many aspiring artists and animators have grown up with 3D and computers, and naturally gravitate to this field as their area of interest. Bringing a blend of studio and classroom experience to offer you thorough coverage of the 3D animation industry, this must-have book shows you what it takes to create compelling and realistic 3D imagery. Serves as the first step to understanding the language of 3D and computer graphics (CG)Covers 3D anim
VIM4.0, Stead-State 3-D Neutron Transport Using ENDF/B or Multigroup Cross Sections
1 - Description of program or function: VIM solves the steady-state neutron or photon transport problem in any detailed three-dimensional geometry using either continuous energy-dependent ENDF nuclear data or multigroup cross sections. Neutron transport is carried out in a criticality mode, or in a fixed source mode (optionally incorporating subcritical multiplication). Photon transport is simulated in the fixed source mode. The geometry options are infinite medium, combinatorial geometry, and hexagonal or rectangular lattices of combinatorial geometry unit cells, and rectangular lattices of cells of assembled plates. Boundary conditions include vacuum, specular and white reflection, and periodic boundaries for reactor cell calculations. The VIM 4.0 distribution includes data from ENDF/B-IV, ENDF/B-V, ENDF/B-VI and JEF2.2. Binary sequential data libraries for use with the code system on IBM or Sun workstations are included. ASCII data libraries and a convenient means to convert them to binary on a target machine are included for users on other systems. In addition to be included in the RSICC distribution files, the VIM User Guide is available on the developer's web site http://www.ra.anl.gov/vimguide/. 2 - Methods:VIM uses standard Monte Carlo methods for particle tracking with several optional variance-reduction techniques. These include splitting/Russian roulette, non-terminating absorption with non-analog weight cutoff energy. The keff is determined by the optimum linear combinations of two of the three eigenvalue estimates - analog, collision, and track length. Resonance and smooth cross sections are specified pointwise with linear-linear interpolation, frequently with many thousands of energy points. Unresolved resonances are described by the probability table method, which allows the statistical nature of the evaluated resonance cross sections to be incorporated naturally into self-shielding. Neutron interactions are elastic, inelastic and thermal scattering
The M.E.R.C.U.R.E. calculation code (version 6.3) simulate the photons transport from 15 keV to 10 MeV in three dimensional geometries between volume sources and calculation points. It is based in the integration of attenuation punctual nuclei in straight line with accumulation factors. The accumulation factors take into account the following physical phenomena: photoelectric effect, coherent diffusion, incoherent diffusion, pairs production, radiation secondary sources coming from Bremsstrahlung and fluorescence. The code determines the accumulation factor of a succession of several screens with an innovative iterative method. M.E.R.C.U.R.E. -6.3 integers the punctual nuclei by a Monte Carlo method for which it automatically determines the importance distributions. The results of this code are compared with these ones of the Sn T.W.O.D.A.N.T. code in two one-dimensional configurations. One includes five screens composed of four different materials and the other one three screens. In the configuration with three screens, the second screen is of an infinitesimal thickness. (N.C.)
Omar M. Pecho
2015-08-01
Full Text Available This study investigates the influence of microstructure on the effective ionic and electrical conductivities of Ni-YSZ (yttria-stabilized zirconia anodes. Fine, medium, and coarse microstructures are exposed to redox cycling at 950 °C. FIB (focused ion beam-tomography and image analysis are used to quantify the effective (connected volume fraction (Φeff, constriction factor (β, and tortuosity (τ. The effective conductivity (σeff is described as the product of intrinsic conductivity (σ0 and the so-called microstructure-factor (M: σeff = σ0*M. Two different methods are used to evaluate the M-factor: (1 by prediction using a recently established relationship, Mpred = εβ0.36/τ5.17, and (2 by numerical simulation that provides conductivity, from which the simulated M-factor can be deduced (Msim. Both methods give complementary and consistent information about the effective transport properties and the redox degradation mechanism. The initial microstructure has a strong influence on effective conductivities and their degradation. Finer anodes have higher initial conductivities but undergo more intensive Ni coarsening. Coarser anodes have a more stable Ni phase but exhibit lower YSZ stability due to lower sintering activity. Consequently, in order to improve redox stability, it is proposed to use mixtures of fine and coarse powders in different proportions for functional anode and current collector layers.
Yue, Dan; Lu, Wei; Jin, Lin; Li, Chunyang; Luo, Wen; Wang, Mengnan; Wang, Zhenling; Hao, Jianhua
2014-10-01
Lanthanide doped ZnO mushroom-like 3D hierarchical structures have been fabricated by polyol-mediated method and characterized by various microstructural and optical techniques. The results indicate that the as-prepared ZnO:Ln3+ (Ln = Tb, Eu) samples have a hexagonal phase structure and possess a mushroom-like 3D hierarchical morphology. The length of the whole mushroom from stipe bottom to pileus top is about 1.0 μm, and the diameters of pileus and stipe are about 0.8 μm and 0.4 μm, respectively. It is found that the flow of N2 is the key parameter for the formation of the novel ZnO structure and the addition of (NH4)2HPO4 has a prominent effect on the phase structure and the growth of mushroom-like morphology. The potential mechanism of forming this morphology is proposed. The pileus of the formed mushroom is assembled by several radial ZnO:Ln3+ nanorods, whereas the stipe is composed of over layered ZnO:Ln3+ nanosheets. Moreover, asymmetrical I-V characteristic curves of ZnO:Ln3+ mushrooms indicate that the texture composition of the 3D hierarchical morphology might lead to the asymmetrical transport behavior of electrical conductivity. Lanthanide doped ZnO samples can exhibit red or green emission under the excitation of UV light.Lanthanide doped ZnO mushroom-like 3D hierarchical structures have been fabricated by polyol-mediated method and characterized by various microstructural and optical techniques. The results indicate that the as-prepared ZnO:Ln3+ (Ln = Tb, Eu) samples have a hexagonal phase structure and possess a mushroom-like 3D hierarchical morphology. The length of the whole mushroom from stipe bottom to pileus top is about 1.0 μm, and the diameters of pileus and stipe are about 0.8 μm and 0.4 μm, respectively. It is found that the flow of N2 is the key parameter for the formation of the novel ZnO structure and the addition of (NH4)2HPO4 has a prominent effect on the phase structure and the growth of mushroom-like morphology. The potential
Le Fouest, Vincent; Chami, Malik; Verney, Romaric
2015-02-01
The export of riverine suspended particulate matter (SPM) in the coastal ocean has major implications for the biogeochemical cycles. In the Mediterranean Sea (France), the Rhone River inputs of SPM into the Gulf of Lion (GoL) are highly variable in time, which severely impedes the assessment of SPM fluxes. The objectives of this study are (i) to investigate the prediction of the land-to-ocean flux of SPM using the complementarity (i.e., synergy) between a hydrodynamic sediment transport model and satellite observations, and (ii) to analyze the spatial distribution of the SPM export. An original approach that combines the MARS-3D model with satellite ocean color data is proposed. Satellite-derived SPM and light penetration depth are used to initialize MARS-3D and to validate its predictions. A sensitivity analysis is performed to quantify the impact of riverine SPM size composition and settling rate on the horizontal export of SPM. The best agreement between the model and the satellite in terms of SPM spatial distribution and export is obtained for two conditions: (i) when the relative proportion of "heavy and fast" settling particles significantly increases relative to the "light and slow" ones, and (ii) when the settling rate of heavy and light SPM increases by fivefold. The synergy between MARS-3D and the satellite data improved the SPM flux predictions by 48% near the Rhone River mouth. Our results corroborate the importance of implementing satellite observations within initialization procedures of ocean models since data assimilation techniques may fail for river floods showing strong seasonal variability.
X. Xiao
2009-12-01
Full Text Available Methyl chloride (CH_{3}Cl is a chlorine-containing trace gas in the atmosphere contributing significantly to stratospheric ozone depletion. Large uncertainties in estimates of its source and sink magnitudes and temporal and spatial variations currently exist. GEIA inventories and other bottom-up emission estimates are used to construct a priori maps of the surface fluxes of CH_{3}Cl. The Model of Atmospheric Transport and Chemistry (MATCH, driven by NCEP interannually varying meteorological data, is then used to simulate CH_{3}Cl mole fractions and quantify the time series of sensitivities of the mole fractions at each measurement site to the surface fluxes of various regional and global sources and sinks. We then implement the Kalman filter (with the unit pulse response method to estimate the surface fluxes on regional/global scales with monthly resolution from January 2000 to December 2004. High frequency observations from the AGAGE, SOGE, NIES, and NOAA/ESRL HATS in situ networks and low frequency observations from the NOAA/ESRL HATS flask network are used to constrain the source and sink magnitudes. The inversion results indicate global total emissions around 4100±470 Gg yr^{−1} with very large emissions of 2200±390 Gg yr^{−1} from tropical plants, which turn out to be the largest single source in the CH_{3}Cl budget. Relative to their a priori annual estimates, the inversion increases global annual fungal and tropical emissions, and reduces the global oceanic source. The inversion implies greater seasonal and interannual oscillations of the natural sources and sink of CH_{3}Cl compared to the a priori. The inversion also reflects the strong effects of the 2002/2003 globally widespread heat waves and droughts on global emissions from tropical plants, biomass burning and salt marshes, and on the soil sink.
X. Xiao
2010-06-01
Full Text Available Methyl chloride (CH_{3}Cl is a chlorine-containing trace gas in the atmosphere contributing significantly to stratospheric ozone depletion. Large uncertainties in estimates of its source and sink magnitudes and temporal and spatial variations currently exist. GEIA inventories and other bottom-up emission estimates are used to construct a priori maps of the surface fluxes of CH_{3}Cl. The Model of Atmospheric Transport and Chemistry (MATCH, driven by NCEP interannually varying meteorological data, is then used to simulate CH_{3}Cl mole fractions and quantify the time series of sensitivities of the mole fractions at each measurement site to the surface fluxes of various regional and global sources and sinks. We then implement the Kalman filter (with the unit pulse response method to estimate the surface fluxes on regional/global scales with monthly resolution from January 2000 to December 2004. High frequency observations from the AGAGE, SOGE, NIES, and NOAA/ESRL HATS in situ networks and low frequency observations from the NOAA/ESRL HATS flask network are used to constrain the source and sink magnitudes. The inversion results indicate global total emissions around 4100 ± 470 Gg yr^{−1} with very large emissions of 2200 ± 390 Gg yr^{−1} from tropical plants, which turn out to be the largest single source in the CH_{3}Cl budget. Relative to their a priori annual estimates, the inversion increases global annual fungal and tropical emissions, and reduces the global oceanic source. The inversion implies greater seasonal and interannual oscillations of the natural sources and sink of CH_{3}Cl compared to the a priori. The inversion also reflects the strong effects of the 2002/2003 globally widespread heat waves and droughts on global emissions from tropical plants, biomass burning and salt marshes, and on the soil sink.
Le Guen, E.
2010-11-15
Hybrid laser/MIG-MAG welding shows high advantages compared to laser welding or GMAW arc welding used separately. Thanks to this process, higher productivity can be gained through higher welding speed, higher squeeze tolerance moreover possible improvement of the metallurgical properties of the weld seam can be obtained. However, many operating parameters have to be set up in order to achieve optimal process. The complex physical phenomena, which govern welding process, have to be understood in order to use efficiently this technique in mass production. Understanding of these phenomena is also necessary to program numerical simulations which fit to this process. In the first step, experimental studies have been carried out with GMAW, laser and hybrid welding on samples of S355 steel. Influence of operating parameters has been analyzed through films performed with speed camera and macro-graphies of weld seam cross section. Surface deformations of the melt pool, induced by the arc pressure, weld pool length, droplet detachment and welding speed, have been analyzed precisely from images of the surface melt pool. In a second step, a numerical model was developed using the COMSOL Multiphysics software for MAG, laser and hybrid laser/MAG welding processes. A 3D quasi-stationary model has been calculated from the temperature field within the metal. The originality of the MAG and hybrid model lies in the prediction of the melt pool surface profile used to determine the 3D geometry, by taking into account the material input. The influence of different parameters such as arc power and speed welding on the efficiency as well as the distribution radius of the arc power and the arc pressure are analyzed through validations with different experimental results and different calculation configurations. (author)
J.-D. Paris
2010-07-01
Full Text Available We evaluate the GEOS-Chem atmospheric transport model (v8-02-01 of CO2 over 2003–2006, driven by GEOS-4 and GEOS-5 meteorology from the NASA Goddard Global Modelling and Assimilation Office, using surface, aircraft and space-borne concentration measurements of CO2. We use an established ensemble Kalman filter to estimate a posteriori biospheric+biomass burning (BS+BB and oceanic (OC CO2 fluxes from 22 geographical regions, following the TransCom 3 protocol, using boundary layer CO2 data from a subset of GLOBALVIEW surface sites. Global annual net BS+BB+OC CO2 fluxes over 2004–2006 for GEOS-4 (GEOS-5 meteorology are −4.4±0.9 (−4.2±0.9, −3.9±0.9 (−4.5±0.9, and −5.2±0.9 (−4.9±0.9 Pg C yr−1 , respectively. The regional a posteriori fluxes are broadly consistent in the sign and magnitude of the TransCom-3 study for 1992–1996, but we find larger net sinks over northern and southern continents. We find large departures from our a priori over Europe during summer 2003, over temperate Eurasia during 2004, and over North America during 2005, reflecting an incomplete description of terrestrial carbon dynamics. We find GEOS-4 (GEOS-5 a posteriori CO2 concentrations reproduce the observed surface trend of 1.91–2.43 ppm yr−1, depending on latitude, within 0.15 ppm yr−1 (0.2 ppm yr−1 and the seasonal cycle within 0.2 ppm (0.2 ppm at all latitudes. We find the a posteriori model reproduces the aircraft vertical profile measurements of CO2 over North America and Siberia generally within 1.5 ppm in the free and upper troposphere but can be biased by up to 4–5 ppm in the boundary layer at the start and end of the growing season. The model has a small negative bias in the free troposphere CO2 trend (1.95–2.19 ppm yr−1 compared to AIRS data which has a trend of 2.21–2.63 ppm yr−1 during 2004–2006, consistent with surface data. Model CO2 concentrations in the upper troposphere, evaluated using CONTRAIL (Comprehensive
Zurek, A. J.; Witczak, S.; Dulinski, M.; Wachniew, P.; Rozanski, K.; Kania, J.; Postawa, A.; Karczewski, J.; Moscicki, W. J.
2015-02-01
Groundwater-dependent ecosystems (GDEs) have important functions in all climatic zones as they contribute to biological and landscape diversity and provide important economic and social services. Steadily growing anthropogenic pressure on groundwater resources creates a conflict situation between nature and man which are competing for clean and safe sources of water. Such conflicts are particularly noticeable in GDEs located in densely populated regions. A dedicated study was launched in 2010 with the main aim to better understand the functioning of a groundwater-dependent terrestrial ecosystem (GDTE) located in southern Poland. The GDTE consists of a valuable forest stand (Niepolomice Forest) and associated wetland (Wielkie Błoto fen). It relies mostly on groundwater from the shallow Quaternary aquifer and possibly from the deeper Neogene (Bogucice Sands) aquifer. In July 2009 a cluster of new pumping wells abstracting water from the Neogene aquifer was set up 1 km to the northern border of the fen. A conceptual model of the Wielkie Błoto fen area for the natural, pre-exploitation state and for the envisaged future status resulting from intense abstraction of groundwater through the new well field was developed. The main aim of the reported study was to probe the validity of the conceptual model and to quantify the expected anthropogenic impact on the studied GDTE. A wide range of research tools was used. The results obtained through combined geologic, geophysical, geochemical, hydrometric and isotope investigations provide strong evidence for the existence of upward seepage of groundwater from the deeper Neogene aquifer to the shallow Quaternary aquifer supporting the studied GDTE. Simulations of the groundwater flow field in the study area with the aid of a 3-D flow and transport model developed for Bogucice Sands (Neogene) aquifer and calibrated using environmental tracer data and observations of hydraulic head in three different locations on the study area
Das, Ronnie; Burfeind, Chris W.; Kramer, Greg M.; Seibel, Eric J.
2014-03-01
A minimally-invasive diagnosis of pancreatic cancer is accomplished by obtaining a fine needle aspirate and observing the cell preparations under conventional optical microscopy. As an unavoidable artifact, native tissue architecture is lost, making definite diagnosis of malignancy, or invasive neoplasm, impossible. One solution is the preparation of core biopsies (CBs) within a microfluidic device that are subsequently imaged in 3D. In this paper, porcine pancreas CBs (L = 1-2 cm, D = 0.4-2.0 mm) were formalin-fixed, stained and optically cleared (FocusClear®). In brightfield at 40x, light transmission through the ordinarily opaque CBs was increased 5-15x, and internal islet structures were easily identified 250-300 μm beneath the tissue surface. Typically, specimen preparation is time intensive and requires precise handling since CBs are delicate; thus, fixative, absorptive stain and FocusClear® diffusion were done slowly and manually. To significantly speed up tissue processing, we developed a microfluidic device consisting of both a main channel (L = 12.5 cm, D = 1.415 mm) with a circular cross section used for fixing and transporting the CB and an intersecting U-channel employed for staining. Space between the CB and channel wall provided a key feature not traditionally employed in microfluidic devices, such that at low flow rates (5-10 mL/min) CBs were fixed and stained while the specimen remained stationary. By switching quickly to higher flow rates (15-20 mL/min), we could precisely overcome adhesion and transport the specimen within the channel towards the imaging platform for 3D pathology.
Ms. Swapnali R. Ghadge
2013-08-01
Full Text Available In today’s ever-shifting media landscape, it can be a complex task to find effective ways to reach your desired audience. As traditional media such as television continue to lose audience share, one venue in particular stands out for its ability to attract highly motivated audiences and for its tremendous growth potential the 3D Internet. The concept of '3D Internet' has recently come into the spotlight in the R&D arena, catching the attention of many people, and leading to a lot of discussions. Basically, one can look into this matter from a few different perspectives: visualization and representation of information, and creation and transportation of information, among others. All of them still constitute research challenges, as no products or services are yet available or foreseen for the near future. Nevertheless, one can try to envisage the directions that can be taken towards achieving this goal. People who take part in virtual worlds stay online longer with a heightened level of interest. To take advantage of that interest, diverse businesses and organizations have claimed an early stake in this fast-growing market. They include technology leaders such as IBM, Microsoft, and Cisco, companies such as BMW, Toyota, Circuit City, Coca Cola, and Calvin Klein, and scores of universities, including Harvard, Stanford and Penn State.
D. Pletinckx
2012-09-01
Full Text Available The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.
Hamdani, Sid Ahmed
2010-09-15
The objective of this communication is analyze the energy efficiency of the transport system in Algeria and to show the areas of possible rationalization in this sector. Our approach is to analyze the existing configuration of the sector and its impact on energy consumption, by developing a sectional model Bottom Up, where the transport park has been modified by the means used. We have shown that the potential to improve the transport system energy efficiency is important and have recommended some options aimed at the sector organisation and aimed at increasing the relative part of transport systems to make it more energy efficient. [French] L'objectif de cette communication est d'analyser l'efficacite energetique du systeme de transport algerien et de montrer les gisements de rationalisation possibles dans ce secteur. Notre approche consiste a analyser la configuration existante du secteur et son impact sur la consommation d'energie, en elaborant un modele sectoriel Bottom Up, ou le parc de transport a ete desagrege par moyen utilise. Nous avons montre que le potentiel d'amelioration de la performance energetique du systeme de transport est important et avons recommande quelques options ciblant l'organisation du secteur et visant a augmenter la part relative de moyens de transport plus efficace energetiquement.
This book explains modeling of solid works 3D and application of 3D CAD/CAM. The contents of this book are outline of modeling such as CAD and 2D and 3D, solid works composition, method of sketch, writing measurement fixing, selecting projection, choosing condition of restriction, practice of sketch, making parts, reforming parts, modeling 3D, revising 3D modeling, using pattern function, modeling necessaries, assembling, floor plan, 3D modeling method, practice floor plans for industrial engineer data aided manufacturing, processing of CAD/CAM interface.
Helzel, Christiane; Taetz, Bertram
2012-01-01
Numerical methods for solving the ideal magnetohydrodynamic (MHD) equations in more than one space dimension must confront the challenge of controlling errors in the discrete divergence of the magnetic field. One approach that has been shown successful in stabilizing MHD calculations are constrained transport (CT) schemes. CT schemes can be viewed as predictor-corrector methods for updating the magnetic field, where a magnetic field value is first predicted by a method that does not exactly preserve the divergence-free condition on the magnetic field, followed by a correction step that aims to control these divergence errors. In Helzel et al. (2011) the authors presented an unstaggered constrained transport method for the MHD equations on 3D Cartesian grids. In this work we generalize the method of Helzel et al. (2011) in three important ways: (1) we remove the need for operator splitting by switching to an appropriate method of lines discretization and coupling this with a non-conservative finite volume meth...
1 - Description of program or function: BOT3P was originally conceived as a set of standard FORTRAN 77 language programs in order to give the users of the DORT and TORT deterministic transport codes some useful diagnostic tools to prepare and check their input data files. Later versions extended the possibility to produce the geometrical, material distribution and fixed neutron source data to other deterministic transport codes such as TWODANT/THREEDANT of the DANTSYS system, PARTISN and, potentially, to any transport code through BOT3P binary output files that can be easily interfaced (see, for example, the Russian two-dimensional (2D) and three-dimensional (3D) discrete ordinates neutron, photon and charged particle transport codes KASKAD-S-2.5 and KATRIN-2.0). As from Version 5.1 BOT3P contained important additions specifically addressed to radiation transport analysis for medical applications. BOT3P-5.2 contains new graphics capabilities. Some of them enable users to select space sub-domains of the total mesh grid in order to improve the zoom simulation of the geometry, both in 2D cuts and in 3D. Moreover the new BOT3P module (PDTM) may improve the interface of BOT3P geometrical models to transport analysis codes. The following programs are included in the BOT3P software package: GGDM, DDM, GGTM, DTM2, DTM3, RVARSCL, COMPARE, MKSRC, CATSM, DTET, and PDTM. The main features of these different programs are described. 2 - Methods: GGDM and GGTM work similarly from the logical point of view. Since the 3D case is more general, the following description refers to GGTM. All the co-ordinate values that characterise the geometrical scheme at the basis of the 3D transport code geometrical and material model are read, sorted and all stored if different from the neighbouring ones more than an input tolerance established by the user. These co-ordinates are always present in the fine-mesh boundary arrays independently of the mesh grid refinement options, because they
Felician ALECU
2010-01-01
Full Text Available Many professionals and 3D artists consider Blender as being the best open source solution for 3D computer graphics. The main features are related to modeling, rendering, shading, imaging, compositing, animation, physics and particles and realtime 3D/game creation.
3d-3d correspondence revisited
Chung, Hee-Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr
2016-04-01
In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d {N}=2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. We also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.
Brdnik, Lovro
2015-01-01
Diplomsko delo analizira trenutno stanje 3D tiskalnikov na trgu. Prikazan je razvoj in principi delovanja 3D tiskalnikov. Predstavljeni so tipi 3D tiskalnikov, njihove prednosti in slabosti. Podrobneje je predstavljena zgradba in delovanje koračnih motorjev. Opravljene so meritve koračnih motorjev. Opisana je programska oprema za rokovanje s 3D tiskalniki in komponente, ki jih potrebujemo za izdelavo. Diploma se oklepa vprašanja, ali je izdelava 3D tiskalnika bolj ekonomična kot pa naložba v ...
Dalla Valle, Giacomo; Gamberi, Fabiano; Rocchini, Patrizia; Minisini, Daniel; Errera, Alessia; Baglioni, Luca; Trincardi, Fabio
2013-08-01
Three-dimensional (3D) seismic-reflection data has shed light on the character of a series of mass transport complexes (MTCs) emplaced during the Pleistocene in the Pescara Basin (Central Adriatic Sea, Italy). The Pescara Basin is the Plio-Pleistocene inner foredeep of the Central Apennines orogen, which was filled by a rapidly prograding, margin-scale clinoforms system. Three MTCs punctuate the normal turbiditic and hemipelagic sedimentary succession of the Pescara Basin foredeep. MTC_0 is the oldest one and covers an area of around 74 km2. It is composed of three different mass transport deposits (MTDs) resulting from individual collapses that involved a shelf-edge delta during a period of relative sea level rise. MTC_1, the intermediate age MTC, is the largest one, with an area of 90 km2. It has a 10 km wide cookie-bite headwall region that indents the upper slope and, in places, reaches the continental shelf-break. MTC_1 is made up of four laterally and vertically stacked MTDs which are the result of a composite set of failures that migrated progressively upslope in a sedimentary setting dominated by contourite deposits. MTC_2 is the youngest and the smallest one, with an area of 55 km2. It has a 5 km long headwall confined in correspondence with a sedimentary bulge developed in the upper slope. Its geomorphic setting leads us to consider two different episodes of failure rooted at different depths. The investigation of the MTCs, through the coupling of 3D seismic geomorphology, seismic facies analysis and rollover trajectory analysis, reveals that the type of sedimentary environment, the rate of sediment accumulation, the source region and the depth of rooting of the failure, are the major controlling factors on MTC evolution and emplacement. Each MTC of the Pescara Basin foredeep is generally confined within a discrete clinotheme. Finally, the rollover trajectory analysis has shown that, in the PB foredeep, a sediment failure can possibly occur at any
Meulien Ohlmann, Odile
2013-02-01
Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?
Ubrich E.
2006-11-01
émontrée et a pu être attribuée à certains types d'hydrocarbures dont la nature a été précisée. Les résultats obtenus ont permis de conclure que le phénomène principal mis en jeu au cours du vieillissement est une hydrolyse causée par l'eau absorbée dans le matériau et qui entraîne une coupure des chaînes macromoléculaires et la fragilisation du polymère. 3 D'étendre l'application du modèle établi avec des coupes gazoles au cas d'un vieillissement dans un pétrole brut et de vérifier son caractère prédictif. Polyamide 11 is used as a leakproof sheath inside flexible flowlines for petroleum products. Under some operating conditions, this polymer undergoes a degradation of its original physicochemical and mechanical properties, which may be assimilated with a phenomenon of aging. Material exchanges occur between polyamide 11 and the fluid transported. The components present in the fluid (water, hydrocarbons may be absorbed, and the principal additive of the material (the plasticizer is extracted. This study was carried out to determine the influence of the composition of the chemical environment of aging on the properties of polyamide 11. In the first phase, a new analysis method was developed for quantifying diffusing materials in polyamide 11. Effectively, several techniques can be used for determining such materials. However, interference problems may be encountered when the polymer is in contact with oil containing sulfur-bearing products. Likewise, none of these techniques is capable of simultaneously making a complete analysis of all the materials. The principle of the method developed consists in performing a thermodesorption of the different materials present in the polymer and in analyzing them on line by medium-resolution mass spectrometry (resolution = 3000. This resolution is also capable of determining the distribution, by chemical families, of the hydrocarbons absorbed. The method was checked with aged polyamide 11 samples containing either
Picot-Colbeaux, Géraldine; Devau, Nicolas; Thiéry, Dominique; Pettenati, Marie; Surdyk, Nicolas; Parmentier, Marc; Amraoui, Nadia; Crastes de Paulet, François; André, Laurent
2016-04-01
Chalk aquifer is the main water resource for domestic water supply in many parts in northern France. In same basin, groundwater is frequently affected by quality problems concerning nitrates. Often close to or above the drinking water standards, nitrate concentration in groundwater is mainly due to historical agriculture practices, combined with leakage and aquifer recharge through the vadose zone. The complexity of processes occurring into such an environment leads to take into account a lot of knowledge on agronomy, geochemistry and hydrogeology in order to understand, model and predict the spatiotemporal evolution of nitrate content and provide a decision support tool for the water producers and stakeholders. To succeed in this challenge, conceptual and numerical models representing accurately the Chalk aquifer specificity need to be developed. A multidisciplinary approach is developed to simulate storage and transport from the ground surface until groundwater. This involves a new agronomic module "NITRATE" (NItrogen TRansfer for Arable soil to groundwaTEr), a soil-crop model allowing to calculate nitrogen mass balance in arable soil, and the "PHREEQC" numerical code for geochemical calculations, both coupled with the 3D transient groundwater numerical code "MARTHE". Otherwise, new development achieved on MARTHE code allows the use of dual porosity and permeability calculations needed in the fissured Chalk aquifer context. This method concerning the integration of existing multi-disciplinary tools is a real challenge to reduce the number of parameters by selecting the relevant equations and simplifying the equations without altering the signal. The robustness and the validity of these numerical developments are tested step by step with several simulations constrained by climate forcing, land use and nitrogen inputs over several decades. In the first time, simulations are performed in a 1D vertical unsaturated soil column for representing experimental nitrates
Gaulier J. M.
2006-12-01
Full Text Available 3D gravity modelling is combined with seismic refraction and reflection data to constrain a new Moho depth map in the Liguro-Provençal Basin (Western Mediterranean Sea. At seismically controlled points, the misfit between the gravimetric solution and the seismic data is about 2 km for a range of Moho depth between 12 km (deep basin and 30 km (mainlands. The oceanic crust thickness in the deep basin (5 km is smaller than the average oceanic crust thickness reported in open oceans (7 km, pointing to a potential mantle temperature 30°C to 50°C below normal and/or very slow oceanic spreading rate. Oceanic crust thickness is decreasing towards the Ligurian Sea and towards the continent-ocean boundary to values as small as 2 km. Poor magma supply is a result of low potential mantle temperature at depth, lateral thermal conduction towards unextended continental margin, and decrease of the oceanic spreading rate close to the pole of opening in the Ligurian Sea. Re-examination of magnetic data (paleomagnetic data and magnetic lineations indicates that opening of the Liguro-Provençal Basin may have ceased as late as Late Burdigalian (16. 5 Ma or even later. The absence of significant time gap between cessation of opening in the Liguro-Provençal Basin and rifting of the Tyrrhenian domain favours a continuous extension mechanism since Upper Oligocene driven by the African trench retreat. Ce rapport présente un travail commun avec le Laboratoire de géodynamique de l'École normale supérieure (ENS. Ce travail doit être resitué dans son contexte : l'étude régionale du golfe du Lion a été possible dans le cadre du projet européen Integrated Basin Studies. Le développement du code d'inversion 3D avait fait l'objet de conventions avec l'ENS pendant les années précédentes. La mise en Suvre d'une telle inversion est désormais possible à l'IFP. Il n'y a pas d'interface pour ce calculateur. L'aide des collègues de l'ENS est souhaitable pour la
Mobile tomographs often have the problem that high spatial resolution is impossible owing to the position or setup of the tomograph. While the tree tomograph developed by Messrs. Isotopenforschung Dr. Sauerwein GmbH worked well in practice, it is no longer used as the spatial resolution and measuring time are insufficient for many modern applications. The paper shows that the mechanical base of the method is sufficient for 3D CT measurements with modern detectors and X-ray tubes. CT measurements with very good statistics take less than 10 min. This means that mobile systems can be used, e.g. in examinations of non-transportable cultural objects or monuments. Enhancement of the spatial resolution of mobile tomographs capable of measuring in any position is made difficult by the fact that the tomograph has moving parts and will therefore have weight shifts. With the aid of tomographies whose spatial resolution is far higher than the mechanical accuracy, a correction method is presented for direct integration of the Feldkamp algorithm
Zhang, Y.; Jacob, D. J.; Dutkiewicz, S.; Amos, H. M.; Long, M. S.; Sunderland, E. M.
2014-12-01
Rivers are estimated to deliver 27 Mmol a-1 of mercury (Hg) to ocean margins, which is comparable to the global atmospheric deposition flux of Hg to the ocean. Previous studies presumed that most of this riverine Hg is sequestered by settling to the coastal regions. However, there has been little investigation of the mechanism and efficiency with which this sequestration takes place, and the implications for riverine influence in different ocean regions. Here we develop a global 3-D chemical transport model for Hg in the ocean (MITgcm-Hg) with ecology (DARWIN model). We track offshore export of the discharged Hg from heterogeneous river systems over different ocean regions, and how it is influenced by the interaction of Hg in a variety of geochemical forms with carbon and suspended particles. We constrain our model assumptions with available offshore observations that bear strong riverine signals. Modeling results suggest that some of the riverine Hg is highly refractory, sorbs strongly to particles and does not follow equilibrium partitioning with the dissolved phase. Simulated global Hg evasion from riverine sources is 50 times larger without this refractory particulate pool, which results in a total evasion flux two times larger than our current best estimate. Based on a typology system of global rivers, we calculate that 10% to 60% of the particulate Hg from different rivers settles in ocean margin sediments because of subgrid sedimentation processes. The remaining 7.5 Mmol a-1 (28% of total river discharge) is available for offshore transport, where it undergoes further sedimentation to the shelf (5.3 Mmol a-1) as well as evasion to the atmosphere (0.44 Mmol a-1). Only 1.7 Mmol a-1 (6.4% of the global riverine Hg) reaches the open ocean, although that fraction varies from 2.6% in East Asia because of the blockage of Korean Peninsula to 25% in east North America facilitated by the Gulf Stream. We find large riverine influences over coastal oceans off East Asia
1 - Description of program or function: TORT calculates the flux or fluence of particles due to particles incident upon the system from extraneous sources or generated internally as a result of interaction with the system. TORT is used in two- or three- dimensional geometric systems, and DORT is used in one- or two- dimensional geometric systems. The principle application is to the deep-penetration transport of neutrons and photons. Certain reactor eigenvalue problems can also be solved. Numerous printed edits of the results are available, and results can be transferred to output files for subsequent analysis. Note that the PC release is 2.7.3. 2 - Method of solution: The Boltzmann transport equation is solved using the method of discrete ordinates to treat the directional variable and finite-difference methods to treat spatial variables. Energy dependence is treated using a multigroup formulation. Time dependence is not treated. Starting in one corner of a mesh, at the highest energy, and with starting guesses for implicit sources, boundary conditions and recursion relationships are used to sweep into the mesh for each discrete direction independently. Integral quantities such as scalar flux are obtained from weighted sums over the directional results. The calculation then proceeds to lower energy groups, one at a time. Iterations are used to resolve implicitness caused by scattering between directions within a single energy group, by scattering from an energy group to another group previously calculated, by fission, and by certain boundary conditions. Methods are available to accelerate convergence. Anisotropic scattering is represented by a Legendre expansion of arbitrary order, and methods are available to mitigate the effect of negative scattering estimates resulting from finite truncation of the expansion. Direction sets can be biased, concentrating work into directions of particular interest. Fixed sources can be specified at either external or internal mesh
Tournay, Bruno; Rüdiger, Bjarne
2006-01-01
3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s.......3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s....
Roberto Rinaldi
2014-12-01
Full Text Available After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.
Costa i Torres, Meritxell
2012-01-01
Introduction Heteromeric amino acid transporters (HATs) are composed of a heavy subunit (rBAT or 4F2hc) and a light subunit (b0 + AT, ASC1, LAT1, LAT2, y + LAT1, y + LAT2 and xCT), joined by a disulfide bridge (Chillaron et al. 2001). rBAT and 4F2hc are type II membrane glycoproteins (N-terminal cytoplasmic). Both have a single transmembrane segment, an N-terminal intracellular tail and an extracellular domain (ectodomain). As far as we know, the role of the heavy subunit is facilitating ...
We present the TORT solutions to the 3D transport codes' suite of benchmarks exercise. An overview of benchmark configurations is provided, followed by a description of the TORT computational model we developed to solve the cases comprising the benchmark suite. In the numerical experiments reported in this paper, we chose to refine the spatial and angular discretizations simultaneously, from the coarsest model (40 x 40 x 40, 200 angles) to the finest model (160 x 160 x 160, 800 angles). The MCNP reference solution is used for evaluating the effect of model-refinement on the accuracy of the TORT solutions. The presented results show that the majority of benchmark quantities are computed with good accuracy by TORT, and that the accuracy improves with model refinement. However, this deliberately severe test has exposed some deficiencies in both deterministic and stochastic solution approaches. Specifically, TORT fails to converge the inner iterations in some benchmark configurations while MCNP produces zero tallies, or drastically poor statistics for some benchmark quantities. We conjecture that TORT's failure to converge is driven by ray effects in configurations with low scattering ratio and/or highly skewed computational cells, i.e. aspect ratio far from unity. The failure of MCNP occurs in quantities tallied over a very small area or volume in physical space, or quantities tallied many (∼25) mean free paths away from the source. Hence automated, robust, and reliable variance reduction techniques are essential for obtaining high quality reference values of the benchmark quantities. Preliminary results of the benchmark exercise indicate that the occasionally poor performance of TORT is shared with other deterministic codes. Armed with this information, method developers can now direct their attention to regions in parameter space where such failures occur and design alternative solution approaches for such instances
Qualité de l’offre et usage du transport public en milieu urbain
Cyrille Genre-Grandpierre
2007-06-01
Full Text Available L’objectif de ce travail est de mieux cerner les déterminants de la mobilité quotidienne en bus en milieu urbain. Il s’agit en particulier d’étudier dans quelle mesure la qualité de l’offre de transport en bus en détermine l’intensité de l’usage. Une première étape a consisté à élaborer un indicateur décrivant localement la qualité de l’accessibilité fournie par le bus. Dans un second temps, des données originales portant sur les déplacements quotidiens à Besançon ont été collectées grâce à une enquête téléphonique, puis implémentées dans un Système d’Information Géographique. Dans un troisième temps, la mise en relation de l’offre et de l’usage du bus a permis de montrer que la qualité de l’offre bus n’en explique l’usage qu’à un niveau très agrégé, mais qu’elle explique en revanche bien la satisfaction quant à cet usage. Plutôt qu’à travers une estimation globale de la qualité de l’offre bus, il est apparu que ce n’est que dans la comparaison de l’offre bus et de l’offre automobile sur un ensemble d’origines-destinations bien précis que l’on parvenait à comprendre les ressorts du choix modal.
Valenza, Enrico
2015-01-01
This book is aimed at the professionals that already have good 3D CGI experience with commercial packages and have now decided to try the open source Blender and want to experiment with something more complex than the average tutorials on the web. However, it's also aimed at the intermediate Blender users who simply want to go some steps further.It's taken for granted that you already know how to move inside the Blender interface, that you already have 3D modeling knowledge, and also that of basic 3D modeling and rendering concepts, for example, edge-loops, n-gons, or samples. In any case, it'
Hundebøl, Jesper
wave of new building information modelling tools demands further investigation, not least because of industry representatives' somewhat coarse parlance: Now the word is spreading -3D digital modelling is nothing less than a revolution, a shift of paradigm, a new alphabet... Research qeustions. Based...... on empirical probes (interviews, observations, written inscriptions) within the Danish construction industry this paper explores the organizational and managerial dynamics of 3D Digital Modelling. The paper intends to - Illustrate how the network of (non-)human actors engaged in the promotion (and arrest) of 3......D Modelling (in Denmark) stabilizes - Examine how 3D Modelling manifests itself in the early design phases of a construction project with a view to discuss the effects hereof for i.a. the management of the building process. Structure. The paper introduces a few, basic methodological concepts...
Lively, Michael
2010-01-01
Professional Papervision3D describes how Papervision3D works and how real world applications are built, with a clear look at essential topics such as building websites and games, creating virtual tours, and Adobe's Flash 10. Readers learn important techniques through hands-on applications, and build on those skills as the book progresses. The companion website contains all code examples, video step-by-step explanations, and a collada repository.
Full text: The Australian forest fires near Canberra in the summer of 2002/2003 produced large quantities of smoke and various emission products. These fires were very intense to the point where smoke was injected in to the lower stratosphere, as well as being transported many thousands of kilometers zonally. These fire emissions were recorded in both Wollongong, (34.4S, 150.5E, 0.03 km asl), Australia, some hundreds of kilometers to the north east, as well as Lauder (45.0S, 169.7E, 0.37 km asl), New Zealand, nearly 2000 km to the south east of the fire sources. Both of these locations (Wollongong and Lauder), are instrumented sites as part of the Network for the Detection of Atmospheric Composition Change (NDACC). Wollongong has a high resolution FTIR spectrometer with a collocated UV/Visible spectrometer. Lauder is a fully instrumented primary NDAAC site that includes FTIR and UV/Visible spectrometers as well as various ozone measuring capabilities (lidar, balloons, Dobson). Several smoke events were captured at both sites, with enhanced levels of a number of key biomass burning gases recorded by the remote sensing instruments. Included in this suite of scientific data are model studies of the fire events using the 3-D chemical transport model GEOSCHEM, which uses emission data from GFED2 (biomass burning) and EDGAR (global NOx, CO). GEOSCHEM is driven by assimilated meteorological fields from the Goddard Earth Observing System of the NASA Global Modeling and Assimilation Office (GMAO). This presentation will describe the instrumentation involved, the relevant emission gases retrieved and subsequent interpretation in terms of the 3-D model output from GEOSCHEM. (author)
3D Spectroscopic Instrumentation
Bershady, Matthew A
2009-01-01
In this Chapter we review the challenges of, and opportunities for, 3D spectroscopy, and how these have lead to new and different approaches to sampling astronomical information. We describe and categorize existing instruments on 4m and 10m telescopes. Our primary focus is on grating-dispersed spectrographs. We discuss how to optimize dispersive elements, such as VPH gratings, to achieve adequate spectral resolution, high throughput, and efficient data packing to maximize spatial sampling for 3D spectroscopy. We review and compare the various coupling methods that make these spectrographs ``3D,'' including fibers, lenslets, slicers, and filtered multi-slits. We also describe Fabry-Perot and spatial-heterodyne interferometers, pointing out their advantages as field-widened systems relative to conventional, grating-dispersed spectrographs. We explore the parameter space all these instruments sample, highlighting regimes open for exploitation. Present instruments provide a foil for future development. We give an...
Halskov, Kim; Johansen, Stine Liv; Bach Mikkelsen, Michelle
2014-01-01
Three-dimensional projection installations are particular kinds of augmented spaces in which a digital 3-D model is projected onto a physical three-dimensional object, thereby fusing the digital content and the physical object. Based on interaction design research and media studies, this article...... contributes to the understanding of the distinctive characteristics of such a new medium, and identifies three strategies for designing 3-D projection installations: establishing space; interplay between the digital and the physical; and transformation of materiality. The principal empirical case, From...... Fingerplan to Loop City, is a 3-D projection installation presenting the history and future of city planning for the Copenhagen area in Denmark. The installation was presented as part of the 12th Architecture Biennale in Venice in 2010....
Francisco R. Feito Higueruela
2010-04-01
Full Text Available Applications of Geographical Information Systems on several Archeology fields have been increasing during the last years. Recent avances in these technologies make possible to work with more realistic 3D models. In this paper we introduce a new paradigm for this system, the GIS Thetrahedron, in which we define the fundamental elements of GIS, in order to provide a better understanding of their capabilities. At the same time the basic 3D characteristics of some comercial and open source software are described, as well as the application to some samples on archeological researchs
Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran
2016-03-01
We study the conformal bootstrap for a 4-point function of fermions in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge C T . We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N . We also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.
Ms. Swapnali R. Ghadge
2013-01-01
In today’s ever-shifting media landscape, it can be a complex task to find effective ways to reach your desired audience. As traditional media such as television continue to lose audience share, one venue in particular stands out for its ability to attract highly motivated audiences and for its tremendous growth potential the 3D Internet. The concept of '3D Internet' has recently come into the spotlight in the R&D arena, catching the attention of many people, and leading to a lot o...
Kotek, L.
2015-01-01
This paper is about 3D scan of plaster dental casts. The main aim of the work is a hardware and software proposition of 3D scan system for scanning of dental casts. There were used camera, projector and rotate table for this scanning system. Surface triangulation was used, taking benefits of projections of structured light on object, which is being scanned. The rotate table is controlled by PC. The camera, projector and rotate table are synchronized by PC. Controlling of stepper motor is prov...
Villaume, René Domine; Ørstrup, Finn Rude
2002-01-01
Projektet undersøger potentialet for interaktiv 3D design via Internettet. Arkitekt Jørn Utzons projekt til Espansiva blev udviklet som et byggesystem med det mål, at kunne skabe mangfoldige planmuligheder og mangfoldige facade- og rumudformninger. Systemets bygningskomponenter er digitaliseret som...... 3D elementer og gjort tilgængelige. Via Internettet er det nu muligt at sammenstille og afprøve en uendelig række bygningstyper som systemet blev tænkt og udviklet til....
Saunier-Koell, P.
2010-11-15
Nowadays, radiography is the gold standard for the follow up of spinal pathologies. Furthermore, bi-planar radiography allows the assessment of vertebrae configuration, by 3-dimensional (3D) reconstruction. However, multiple radiographic examinations during childhood and adolescence increase the risk of breast cancer among women. To reduce radiation doses, some radiographic assessments could be replaced by the back surface evaluation. This kind of non-invasive procedure allows for acquisition of many clinical parameters useful for spinal pathologies diagnosis and follow-up. Moreover, with an appropriate bio mechanical model, the back surface measurements could be used to estimate the spine configuration. The aim of this thesis is to develop and implement such a model based on personalized internal and external data. The Biomod 3S device has been developed by the company AXS MEDICAL SAS, Bordeaux, France. It offers the possibility of simultaneous acquisitions of X-rays and Moire fringes to obtain 3D reconstructions of the spine and the back surface. Such acquisitions on fifteen scoliotic subjects have enabled us to assess several relationships between internal 3D parameters (for example axial rotation of vertebrae) and external 3D parameters (for example rib hump). The spine configuration and the back surface obtained during this acquisition will also be used as initial position to develop (with Scilab) the multi-body model. The other data used by the model are the back surface in a second position and constraints obtained from the surface in both positions (for example displacement of C7 vertebra). The model has been validated on nine healthy subjects, whose 3D spine and back surface were reconstructed in several positions (standing, leaning forward, sitting) from MRI acquisitions. Moreover, the model has been operated on a pathological subject. This work has explored and utilized many spine and back surface information and leads the way to non-invasive diagnosis
M.M. Voormolen
2007-01-01
textabstractThree dimensional (3D) echocardiography has recently developed from an experimental technique in the â€™90 towards an imaging modality for the daily clinical practice. This dissertation describes the considerations, implementation, validation and clinical application of a unique
Hejlesen, Aske K.; Ovesen, Nis
2012-01-01
This paper presents an experimental approach to teaching 3D modelling techniques in an Industrial Design programme. The approach includes the use of tangible free form models as tools for improving the overall learning. The paper is based on lecturer and student experiences obtained through...
Stenholt, Rasmus; Madsen, Claus B.
2011-01-01
Enabling users to shape 3-D boxes in immersive virtual environments is a non-trivial problem. In this paper, a new family of techniques for creating rectangular boxes of arbitrary position, orientation, and size is presented and evaluated. These new techniques are based solely on position data...
Gerhard Strydom; Cristian Rabiti; Andrea Alfonsi
2012-10-01
PHISICS is a neutronics code system currently under development at the Idaho National Laboratory (INL). Its goal is to provide state of the art simulation capability to reactor designers. The different modules for PHISICS currently under development are a nodal and semi-structured transport core solver (INSTANT), a depletion module (MRTAU) and a cross section interpolation (MIXER) module. The INSTANT module is the most developed of the mentioned above. Basic functionalities are ready to use, but the code is still in continuous development to extend its capabilities. This paper reports on the effort of coupling the nodal kinetics code package PHISICS (INSTANT/MRTAU/MIXER) to the thermal hydraulics system code RELAP5-3D, to enable full core and system modeling. This will enable the possibility to model coupled (thermal-hydraulics and neutronics) problems with more options for 3D neutron kinetics, compared to the existing diffusion theory neutron kinetics module in RELAP5-3D (NESTLE). In the second part of the paper, an overview of the OECD/NEA MHTGR-350 MW benchmark is given. This benchmark has been approved by the OECD, and is based on the General Atomics 350 MW Modular High Temperature Gas Reactor (MHTGR) design. The benchmark includes coupled neutronics thermal hydraulics exercises that require more capabilities than RELAP5-3D with NESTLE offers. Therefore, the MHTGR benchmark makes extensive use of the new PHISICS/RELAP5-3D coupling capabilities. The paper presents the preliminary results of the three steady state exercises specified in Phase I of the benchmark using PHISICS/RELAP5-3D.
Klusoň, Jindřich
2010-01-01
Computer animation has a growing importance and application in the world. With expansion of technologies increases quality of the final animation as well as number of 3D animation software. This thesis is currently mapped animation software for creating animation in film, television industry and video games which are advisable users requirements. Of them were selected according to criteria the best - Autodesk Maya 2011. This animation software is unique with tools for creating special effects...
Andringa, Roel; de Roo, Mees; Hohm, Olaf; Sezgin, Ergin; Townsend, Paul K
2009-01-01
We construct the N=1 three-dimensional supergravity theory with cosmological, Einstein-Hilbert, Lorentz Chern-Simons, and general curvature squared terms. We determine the general supersymmetric configuration, and find a family of supersymmetric adS vacua with the supersymmetric Minkowski vacuum as a limiting case. Linearizing about the Minkowski vacuum, we find three classes of unitary theories; one is the supersymmetric extension of the recently discovered `massive 3D gravity'. Another is a `new topologically massive supergravity' (with no Einstein-Hilbert term) that propagates a single (2,3/2) helicity supermultiplet.
Andringa, Roel; Bergshoeff, Eric A; De Roo, Mees; Hohm, Olaf [Centre for Theoretical Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Sezgin, Ergin [George and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Townsend, Paul K, E-mail: E.A.Bergshoeff@rug.n, E-mail: O.Hohm@rug.n, E-mail: sezgin@tamu.ed, E-mail: P.K.Townsend@damtp.cam.ac.u [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)
2010-01-21
We construct the N=1 three-dimensional supergravity theory with cosmological, Einstein-Hilbert, Lorentz Chern-Simons, and general curvature squared terms. We determine the general supersymmetric configuration, and find a family of supersymmetric adS vacua with the supersymmetric Minkowski vacuum as a limiting case. Linearizing about the Minkowski vacuum, we find three classes of unitary theories; one is the supersymmetric extension of the recently discovered 'massive 3D gravity'. Another is a 'new topologically massive supergravity' (with no Einstein-Hilbert term) that propagates a single (2,3/2) helicity supermultiplet.
Bédécarrats, Jean-Pierre
2010-01-01
Les contraintes environnementales de plus en plus fortes ainsi que les problèmes grandissants de la disponibilité des ressources énergétiques obligent le secteur de l'énergie non seulement à une évolution importante de ses technologies mais aussi à leurs utilisations plus rationnelles. Ce mémoire présente la synthèse de mes initiatives de recherches menées sur le stockage et le transport de l'énergie par chaleur latente essentiellement dans le domaine du froid. Les Matériaux à Changement de P...
Wei-zhong Dai; Raja Nassar
2003-01-01
Heat transport at the microscale is of vital importance in microtechnology applications.The heat transport equation is different from the traditional heat transport equation sincea second order derivative of temperature with respect to time and a third-order mixedderivative of temperature with respect to space and time are introduced. In this study,we develop a hybrid finite element-finite difference (FE-FD) scheme with two levels intime for the three dimensional heat transport equation in a cylindrical thin film with sub-microscale thickness. It is shown that the scheme is unconditionally stable. The scheme isthen employed to obtain the temperature rise in a sub-microscale cylindrical gold film. Themethod can be applied to obtain the temperature rise in any thin films with sub-microscalethickness, where the geometry in the planar direction is arbitrary.
Robin, C.; Chone, T.; GUCKERT, Armand
1987-01-01
L’étude de l’assimilation photosynthétique et du transport des assimilats chez le trèfle blanc a pour objet de préciser le rôle de la feuille dans l’établissement des relations source-puits. Des marquages courts au 14CO2 sont effectués sur les 8 limbes initiés par le stolon obtenu en conditions contrôlées par bouturage d’apex. Le profil photosynthétique de l’ensemble des limbes du stolon met en évidence un effet « âge du limbe source» pour l’assimilation du 14CO2. Les limbes 2, 3 et 4 son...
The Lagrangian method provides estimates of the chemical and physical evolution of air arriving in the daytime boundary layer at Baltimore. Study results indicate a dominant role for regional transport contributions of those days when sulfate air pollution is highest in Baltimor...
Highlights: • WARP, a GPU-accelerated Monte Carlo neutron transport code, has been developed. • The NVIDIA OptiX high-performance ray tracing library is used to process geometric data. • The unionized cross section representation is modified for higher performance. • Reference remapping is used to keep the GPU busy as neutron batch population reduces. • Reference remapping is done using a key-value radix sort on neutron reaction type. - Abstract: In recent supercomputers, general purpose graphics processing units (GPGPUs) are a significant faction of the supercomputer’s total computational power. GPGPUs have different architectures compared to central processing units (CPUs), and for Monte Carlo neutron transport codes used in nuclear engineering to take advantage of these coprocessor cards, transport algorithms must be changed to execute efficiently on them. WARP is a continuous energy Monte Carlo neutron transport code that has been written to do this. The main thrust of WARP is to adapt previous event-based transport algorithms to the new GPU hardware; the algorithmic choices for all parts of which are presented in this paper. It is found that remapping history data references increases the GPU processing rate when histories start to complete. The main reason for this is that completed data are eliminated from the address space, threads are kept busy, and memory bandwidth is not wasted on checking completed data. Remapping also allows the interaction kernels to be launched concurrently, improving efficiency. The OptiX ray tracing framework and CUDPP library are used for geometry representation and parallel dataset-side operations, ensuring high performance and reliability
Hausman, Kalani Kirk
2014-01-01
Get started printing out 3D objects quickly and inexpensively! 3D printing is no longer just a figment of your imagination. This remarkable technology is coming to the masses with the growing availability of 3D printers. 3D printers create 3-dimensional layered models and they allow users to create prototypes that use multiple materials and colors. This friendly-but-straightforward guide examines each type of 3D printing technology available today and gives artists, entrepreneurs, engineers, and hobbyists insight into the amazing things 3D printing has to offer. You'll discover methods for
Szkandera, Jan
2009-01-01
Tato bakalářská práce se zabývá návrhem a realizací systému, který umožní obraz scény zobrazovaný na ploše vnímat prostorově. Prostorové vnímání 2D obrazové informace je umožněno jednak stereopromítáním a jednak tím, že se obraz mění v závislosti na poloze pozorovatele. Tato práce se zabývá hlavně druhým z těchto problémů. This Bachelor's thesis goal is to design and realize system, which allows user to perceive 2D visual information as three-dimensional. 3D visual preception of 2D image i...
Helzel, Christiane; Rossmanith, James A.; Taetz, Bertram
2012-01-01
Numerical methods for solving the ideal magnetohydrodynamic (MHD) equations in more than one space dimension must confront the challenge of controlling errors in the discrete divergence of the magnetic field. One approach that has been shown successful in stabilizing MHD calculations are constrained transport (CT) schemes. CT schemes can be viewed as predictor-corrector methods for updating the magnetic field, where a magnetic field value is first predicted by a method that does not exactly p...
X3D: Extensible 3D Graphics Standard
Daly, Leonard; Brutzman, Don
2007-01-01
The article of record as published may be located at http://dx.doi.org/10.1109/MSP.2007.905889 Extensible 3D (X3D) is the open standard for Web-delivered three-dimensional (3D) graphics. It specifies a declarative geometry definition language, a run-time engine, and an application program interface (API) that provide an interactive, animated, real-time environment for 3D graphics. The X3D specification documents are freely available, the standard can be used without paying any royalties,...
3D game environments create professional 3D game worlds
Ahearn, Luke
2008-01-01
The ultimate resource to help you create triple-A quality art for a variety of game worlds; 3D Game Environments offers detailed tutorials on creating 3D models, applying 2D art to 3D models, and clear concise advice on issues of efficiency and optimization for a 3D game engine. Using Photoshop and 3ds Max as his primary tools, Luke Ahearn explains how to create realistic textures from photo source and uses a variety of techniques to portray dynamic and believable game worlds.From a modern city to a steamy jungle, learn about the planning and technological considerations for 3D modelin
Aboufadel, Edward F.
2014-01-01
The purpose of this short paper is to describe a project to manufacture a regular octohedron on a 3D printer. We assume that the reader is familiar with the basics of 3D printing. In the project, we use fundamental ideas to calculate the vertices and faces of an octohedron. Then, we utilize the OPENSCAD program to create a virtual 3D model and an STereoLithography (.stl) file that can be used by a 3D printer.
The impact of 3D printing on trade and FDI
Abeliansky, Ana L.; Martínez-Zarzoso, Imnaculada; Prettner, Klaus
2015-01-01
This paper analyzes the effects of 3D printing technologies on the volume of trade and on the structure of FDI. A standard model with firm-specific heterogeneity generates three main predictions. First, 3D printers are introduced in areas with high economic activity that also face high transport costs. Second, technological progress related to 3D printing machines leads to a gradual replacement of FDI that relies on traditional production structures with FDI based on 3D printing techniques. A...
Rodrigues, Marcos; Robinson, Alan; Alboul, Lyuba; Brink, Willie
2006-01-01
3D face recognition is an open field. In this paper we present a method for 3D facial recognition based on Principal Components Analysis. The method uses a relatively large number of facial measurements and ratios and yields reliable recognition. We also highlight our approach to sensor development for fast 3D model acquisition and automatic facial feature extraction.
The driver linac of the proposed Rare Isotope Accelerator (RIA) requires a great variety of high intensity, high charge state ion beams. In order to design and to optimize the low energy beamline optics of the RIA front end,we have developed a new parallel three-dimensional model to simulate the low energy, multi-species ion beam formation and transport from the ECR ion source extraction region to the focal plane of the analyzing magnet. A multisection overlapped computational domain has been used to break the original transport system into a number of each subsystem, macro-particle tracking is used to obtain the charge density distribution in this subdomain. The three-dimensional Poisson equation is solved within the subdomain and particle tracking is repeated until the solution converges. Two new Poisson solvers based on a combination of the spectral method and the multigrid method have been developed to solve the Poisson equation in cylindrical coordinates for the beam extraction region and in the Frenet-Serret coordinates for the bending magnet region. Some test examples and initial applications will also be presented
3-D contextual Bayesian classifiers
Larsen, Rasmus
distribution for the pixel values as well as a prior distribution for the configuration of class variables within the cross that is made of a pixel and its four nearest neighbours. We will extend these algorithms to 3-D, i.e. we will specify a simultaneous Gaussian distribution for a pixel and its 6 nearest 3......-D neighbours, and generalise the class variable configuration distributions within the 3-D cross given in 2-D algorithms. The new 3-D algorithms are tested on a synthetic 3-D multivariate dataset....
Taming Supersymmetric Defects in 3d-3d Correspondence
Gang, Dongmin; Romo, Mauricio; Yamazaki, Masahito
2015-01-01
We study knots in 3d Chern-Simons theory with complex gauge group $SL(N,\\mathbb{C})$, in the context of its relation with 3d $\\mathcal{N}=2$ theory (the so-called 3d-3d correspondence). The defect has either co-dimension 2 or co-dimension 4 inside the 6d $(2,0)$ theory, which is compactified on a 3-manifold $\\hat{M}$. We identify such defects in various corners of the 3d-3d correspondence, namely in 3d $SL(N,\\mathbb{C})$ Chern-Simons theory, in 3d $\\mathcal{N}=2$ theory, in 5d $\\mathcal{N}=2$ super Yang-Mills theory, and in the M-theory holographic dual. We can make quantitative checks of the 3d-3d correspondence by computing partition functions at each of these theories. This Letter is a companion to a longer paper, which contains more details and more results.
Dadzis, K.; Vizman, D.; Friedrich, J.
2013-03-01
Directional solidification of large multi-crystalline silicon ingots is a distinctly unsteady process with a complex interaction between melt flow, crystallization interface, and species transport. Both the different time-scales and the three-dimensional character make numerical simulations of this process a challenging task. The complexity of such simulations increases further if external magnetic fields are used to enhance the melt flow. In this contribution, several three-dimensional coupled unsteady calculations are carried out for a 22×22×11 cm3 silicon melt directionally solidified in a traveling magnetic field. The justification of various approximations in the numerical models is discussed with an emphasis on the frequently used quasi steady-state models for the calculation of the interface shape. It is shown that an upward traveling magnetic field leads to a symmetric concave interface shape while a downward field results in a convex interface with a distinct asymmetry at the current supplies. These results agree in both unsteady and quasi steady-state calculations, but only unsteady calculations reveal the flow-induced local oscillations of the interface. The unsteady segregation process of carbon and oxygen impurities exhibits a non-uniform concentration along the crystallization interface although the bulk concentration is near to the complete mixing limit in the cases with a traveling magnetic field.
Wu, Jialin; Li, Keqiang; Shi, Xiaoyong; Liang, Shengkang; Han, Xiurong; Ma, Qimin; Wang, Xiulin
2014-08-01
The rapid economic and social developments in the Luoyuan and Lianjiang counties of Fujian Province, China, raise certain environment and ecosystem issues. The unusual phytoplankton bloom and eutrophication, for example, have increased in severity in Luoyuan Bay (LB). The constant increase of nutrient loads has largely caused the environmental degradation in LB. Several countermeasures have been implemented to solve these environmental problems. The most effective of these strategies is the reduction of pollutant loadings into the sea in accordance with total pollutant load control (TPLC) plans. A combined three-dimensional hydrodynamic transport-transformation model was constructed to estimate the marine environmental capacity of chemical oxygen demand (COD). The allowed maximum loadings for each discharge unit in LB were calculated with applicable simulation results. The simulation results indicated that the environmental capacity of COD is approximately 11×104 t year-1 when the water quality complies with the marine functional zoning standards for LB. A pollutant reduction scheme to diminish the present levels of mariculture- and domestic-based COD loadings is based on the estimated marine COD environmental capacity. The obtained values imply that the LB waters could comply with the targeted water quality criteria. To meet the revised marine functional zoning standards, discharge loadings from discharge units 1 and 11 should be reduced to 996 and 3236 t year-1, respectively.
Silver, J. D.; Brandt, J.; Hvidberg, M.; Frydendall, J.; Christensen, J. H.
2013-01-01
Data assimilation is the process of combining real-world observations with a modelled geophysical field. The increasing abundance of satellite retrievals of atmospheric trace gases makes chemical data assimilation an increasingly viable method for deriving more accurate analysed fields and initial conditions for air quality forecasts. We implemented a three-dimensional optimal interpolation (OI) scheme to assimilate retrievals of NO2 tropospheric columns from the Ozone Monitoring Instrument into the Danish Eulerian Hemispheric Model (DEHM, version V2009.0), a three-dimensional, regional-scale, offline chemistry-transport model. The background error covariance matrix, B, was estimated based on differences in the NO2 concentration field between paired simulations using different meteorological inputs. Background error correlations were modelled as non-separable, horizontally homogeneous and isotropic. Parameters were estimated for each month and for each hour to allow for seasonal and diurnal patterns in NO2 concentrations. Three experiments were run to compare the effects of observation thinning and the choice of observation errors. Model performance was assessed by comparing the analysed fields to an independent set of observations: ground-based measurements from European air-quality monitoring stations. The analysed NO2 and O3 concentrations were more accurate than those from a reference simulation without assimilation, with increased temporal correlation for both species. Thinning of satellite data and the use of constant observation errors yielded a better balance between the observed increments and the prescribed error covariances, with no appreciable degradation in the surface concentrations due to the observation thinning. Forecasts were also considered and these showed rather limited influence from the initial conditions once the effects of the diurnal cycle are accounted for. The simple OI scheme was effective and computationally feasible in this context
3D Membrane Imaging and Porosity Visualization
Sundaramoorthi, Ganesh
2016-03-03
Ultrafiltration asymmetric porous membranes were imaged by two microscopy methods, which allow 3D reconstruction: Focused Ion Beam and Serial Block Face Scanning Electron Microscopy. A new algorithm was proposed to evaluate porosity and average pore size in different layers orthogonal and parallel to the membrane surface. The 3D-reconstruction enabled additionally the visualization of pore interconnectivity in different parts of the membrane. The method was demonstrated for a block copolymer porous membrane and can be extended to other membranes with application in ultrafiltration, supports for forward osmosis, etc, offering a complete view of the transport paths in the membrane.
3D Printing Functional Nanocomposites
Leong, Yew Juan
2016-01-01
3D printing presents the ability of rapid prototyping and rapid manufacturing. Techniques such as stereolithography (SLA) and fused deposition molding (FDM) have been developed and utilized since the inception of 3D printing. In such techniques, polymers represent the most commonly used material for 3D printing due to material properties such as thermo plasticity as well as its ability to be polymerized from monomers. Polymer nanocomposites are polymers with nanomaterials composited into the ...
Baccarne, V. [Ecole Centrale de Nantes (France); Turzo, A.; Bizais, Y. [Centre Hospitalier Universitaire de Brest (France); Farine, M. [Laboratoire de Physique Subatomique et des Technologies Associees - SUBATECH, Centre National de la Recherche Scientifique, 44 - Nantes (France)
1997-10-01
A Monte-Carlo photon transport code to simulate scintigraphy is developed. The scintigraphy consists of injecting a patient with a radioactive tracer (Tc, a 140 keV photon emitter) attached to a biologically active molecule. Complicated physical phenomena, photon interactions, occurring in between the radioactive source emission and the detection of the photon on the gamma-camera, require an accurate description. All these phenomena are very sensitive to the characteristics of human tissues and we had to use segmented computerized tomography slices. A preliminary theoretical study of the physical characteristics (rather badly known) of the biological tissues resulted in a two family classification: soft and bone tissues. By devising a Monte-Carlo simulator a systematic investigation was carried out concerning the relative weight of different types of interaction taking place in the traversed tissue. The importance of bone tissues was evidenced in comparison with the soft tissues, as well as the instability of these phenomena as a function of the patient morphology. These information are crucial in the elaboration and validation of correction techniques applied to the diagnosis images of clinical examinations
3D IBFV : Hardware-Accelerated 3D Flow Visualization
Telea, Alexandru; Wijk, Jarke J. van
2003-01-01
We present a hardware-accelerated method for visualizing 3D flow fields. The method is based on insertion, advection, and decay of dye. To this aim, we extend the texture-based IBFV technique for 2D flow visualization in two main directions. First, we decompose the 3D flow visualization problem in a
3D Elevation Program—Virtual USA in 3D
Lukas, Vicki; Stoker, J.M.
2016-01-01
The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.
Connell, Ellery
2011-01-01
Helping graphic designers expand their 2D skills into the 3D space The trend in graphic design is towards 3D, with the demand for motion graphics, animation, photorealism, and interactivity rapidly increasing. And with the meteoric rise of iPads, smartphones, and other interactive devices, the design landscape is changing faster than ever.2D digital artists who need a quick and efficient way to join this brave new world will want 3D for Graphic Designers. Readers get hands-on basic training in working in the 3D space, including product design, industrial design and visualization, modeling, ani
Griffey, Jason
2014-01-01
As the maker movement continues to grow and 3-D printers become more affordable, an expanding group of hobbyists is keen to explore this new technology. In the time-honored tradition of introducing new technologies, many libraries are considering purchasing a 3-D printer. Jason Griffey, an early enthusiast of 3-D printing, has researched the marketplace and seen several systems first hand at the Consumer Electronics Show. In this report he introduces readers to the 3-D printing marketplace, covering such topics asHow fused deposition modeling (FDM) printing workBasic terminology such as build
Larsen, Rasmus
1997-01-01
. This includes the specification of a Gaussian distribution for the pixel values as well as a prior distribution for the configuration of class variables within the cross that is m ade of a pixel and its four nearest neighbours. We will extend this algorithm to 3-D, i.e. we will specify a simultaneous Gaussian...... distr ibution for a pixel and its 6 nearest 3-D neighbours, and generalise the class variable configuration distribution within the 3-D cross. The algorithm is tested on a synthetic 3-D multivariate dataset....
3D Bayesian contextual classifiers
Larsen, Rasmus
2000-01-01
We extend a series of multivariate Bayesian 2-D contextual classifiers to 3-D by specifying a simultaneous Gaussian distribution for the feature vectors as well as a prior distribution of the class variables of a pixel and its 6 nearest 3-D neighbours.......We extend a series of multivariate Bayesian 2-D contextual classifiers to 3-D by specifying a simultaneous Gaussian distribution for the feature vectors as well as a prior distribution of the class variables of a pixel and its 6 nearest 3-D neighbours....