WorldWideScience

Sample records for global 3d simulations

  1. A global simulation of ICRF heating in a 3D magnetic configuration

    International Nuclear Information System (INIS)

    Murakami, S.; Fukuyama, A.; Akutsu, T.

    2005-01-01

    A global simulation code for the ICRF heating analysis in a three-dimensional (3D) magnetic configuration is developed combining two global simulation codes; a drift kinetic equation solver, GNET, and a wave field solver, TASK/WM. Both codes take into account 3D geometry using the numerically obtained 3D MHD equilibrium. The developed simulation code is applied to the LHD configuration as an example. Characteristics of energetic ion distributions in the phase space are clarified in LHD. The simulation results are also compared with experimental results by evaluating the count number of the neutral particle analyzer using the obtained energetic ion distribution, and a relatively good agreement is obtained. (author)

  2. 3D Surgical Simulation

    OpenAIRE

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2010-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive ...

  3. 3D Surgical Simulation

    Science.gov (United States)

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  4. MERIDIONAL CIRCULATION DYNAMICS FROM 3D MAGNETOHYDRODYNAMIC GLOBAL SIMULATIONS OF SOLAR CONVECTION

    International Nuclear Information System (INIS)

    Passos, Dário; Charbonneau, Paul; Miesch, Mark

    2015-01-01

    The form of solar meridional circulation is a very important ingredient for mean field flux transport dynamo models. However, a shroud of mystery still surrounds this large-scale flow, given that its measurement using current helioseismic techniques is challenging. In this work, we use results from three-dimensional global simulations of solar convection to infer the dynamical behavior of the established meridional circulation. We make a direct comparison between the meridional circulation that arises in these simulations and the latest observations. Based on our results, we argue that there should be an equatorward flow at the base of the convection zone at mid-latitudes, below the current maximum depth helioseismic measures can probe (0.75 R ⊙ ). We also provide physical arguments to justify this behavior. The simulations indicate that the meridional circulation undergoes substantial changes in morphology as the magnetic cycle unfolds. We close by discussing the importance of these dynamical changes for current methods of observation which involve long averaging periods of helioseismic data. Also noteworthy is the fact that these topological changes indicate a rich interaction between magnetic fields and plasma flows, which challenges the ubiquitous kinematic approach used in the vast majority of mean field dynamo simulations

  5. The 3-D Tropical Convective Cloud Spectrum in AMIE Radar Observations and Global Climate Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, Courtney [Texas A & M Univ., College Station, TX (United States). Dept. of Atmospheric Sciences

    2015-08-31

    During the three years of this grant performance, the PI and her research group have made a number of significant contributions towards determining properties of tropical deep convective clouds and how models depict and respond to the heating associated with tropical convective systems. The PI has also been an active ARM/ASR science team member, including playing a significant role in AMIE and GoAmazon2014/5. She served on the DOE ASR radar science steering committee and was a joint chair of the Mesoscale Convective Organization group under the Cloud Life Cycle working group. This grant has funded a number of graduate students, many of them women, and the PI and her group have presented their DOE-supported work at various universities and national meetings. The PI and her group participated in the AMIE (2011-12) and GoAmazon2014/5 (2014-15) DOE field deployments that occurred in the tropical Indian Ocean and Brazilian Amazon, respectively. AMIE observational results (DePasquale et al. 2014, Feng et al. 2014, Ahmed and Schumacher 2015) focus on the variation and possible importance of Kelvin waves in various phases of the Madden-Julian Oscillation (MJO), on the synergy of the different wavelength radars deployed on Addu Atoll, and on the importance of humidity thresholds in the tropics on stratiform rain production. Much of the PIs GoAmazon2014/5 results to date relate to overviews of the observations made during the field campaign (Martin et al. 2015, 2016; Fuentes et al. 2016), but also include the introduction of the descending arm and its link to ozone transport from the mid-troposphere to the surface (Gerken et al. 2016). Vertical motion and mass flux profiles from GoAmazon (Giangrande et al. 2016) also show interesting patterns between seasons and provide targets for model simulations. Results from TWP-ICE (Schumacher et al. 2015), which took place in Darwin, Australia in 2006 show that vertical velocity retrievals from the profilers provide structure to

  6. 3D Visualization of Global Ocean Circulation

    Science.gov (United States)

    Nelson, V. G.; Sharma, R.; Zhang, E.; Schmittner, A.; Jenny, B.

    2015-12-01

    Advanced 3D visualization techniques are seldom used to explore the dynamic behavior of ocean circulation. Streamlines are an effective method for visualization of flow, and they can be designed to clearly show the dynamic behavior of a fluidic system. We employ vector field editing and extraction software to examine the topology of velocity vector fields generated by a 3D global circulation model coupled to a one-layer atmosphere model simulating preindustrial and last glacial maximum (LGM) conditions. This results in a streamline-based visualization along multiple density isosurfaces on which we visualize points of vertical exchange and the distribution of properties such as temperature and biogeochemical tracers. Previous work involving this model examined the change in the energetics driving overturning circulation and mixing between simulations of LGM and preindustrial conditions. This visualization elucidates the relationship between locations of vertical exchange and mixing, as well as demonstrates the effects of circulation and mixing on the distribution of tracers such as carbon isotopes.

  7. Global ice volume variations through the last glacial cycle simulated by a 3-D ice-dynamical model

    NARCIS (Netherlands)

    Bintanja, R.; Wal, R.S.W. van de; Oerlemans, J.

    2002-01-01

    A coupled ice sheet—ice shelf—bedrock model was run at 20km resolution to simulate the evolution of global ice cover during the last glacial cycle. The mass balance model uses monthly mean temperature and precipitation as input and incorporates the albedo—mass balance feedback. The model is forced

  8. 3D Printing and Global Value Chains

    DEFF Research Database (Denmark)

    Rehnberg, Märtha; Ponte, Stefano

    From the birth of industrialization, access to new technology has been a decisive factor in how value added is created and distributed across networks of global production. This article provides a balanced assessment of the potential impact that one of these technologies (3D printing, or 3DP) may...

  9. Simulating 3D deformation using connected polygons

    Science.gov (United States)

    Tarigan, J. T.; Jaya, I.; Hardi, S. M.; Zamzami, E. M.

    2018-03-01

    In modern 3D application, interaction between user and the virtual world is one of an important factor to increase the realism. This interaction can be visualized in many forms; one of them is object deformation. There are many ways to simulate object deformation in virtual 3D world; each comes with different level of realism and performance. Our objective is to present a new method to simulate object deformation by using a graph-connected polygon. In this solution, each object contains multiple level of polygons in different level of volume. The proposed solution focusses on performance rather while maintaining the acceptable level of realism. In this paper, we present the design and implementation of our solution and show that this solution is usable in performance sensitive 3D application such as games and virtual reality.

  10. Numerical Simulation of 3-D Wave Crests

    Institute of Scientific and Technical Information of China (English)

    YU Dingyong; ZHANG Hanyuan

    2003-01-01

    A clear definition of 3-D wave crest and a description of the procedures to detect the boundary of wave crest are presented in the paper. By using random wave theory and directional wave spectrum, a MATLAB-platformed program is designed to simulate random wave crests for various directional spectral conditions in deep water. Statistics of wave crests with different directional spreading parameters and different directional functions are obtained and discussed.

  11. A degradation approach to accelerate simulations to steady-state in a 3-D tracer transport model of the global ocean

    Energy Technology Data Exchange (ETDEWEB)

    Aumont, O.; Orr, J.C.; Marti, O. [CEA Saclay, Gif-sur-Yvette (France). Lab. de Modelisation du Climat et de l`Environnement; Jamous, D.; Monfray, P. [Centre des Faibles Radioactivites, Laboratoire mixte CNRS-CEA, L`Orme des Merisiers, Bt. 709/LMCE, CE Saclay, F-91191 Gif sur Yvette Cedex (France); Madec, G. [Laboratoire d`Oceanographie Dynamique et de Climatologie, (CNRS/ORSTOM/UPMC) Universite Paris VI, 4 place Jussieu, Paris (France)

    1998-02-01

    We have developed a new method to accelerate tracer simulations to steady-state in a 3D global ocean model, run off-line. Using this technique, our simulations for natural {sup 14}C ran 17 times faster when compared to those made with the standard nonaccelerated approach. For maximum acceleration we wish to initialize the model with tracer fields that are as close as possible to the final equilibrium solution. Our initial tracer fields were derived by judiciously constructing a much faster, lower-resolution (degraded), off-line model from advective and turbulent fields predicted from the parent on-line model, an ocean general circulation model (OGCM). No on-line version of the degraded model exists; it is based entirely on results from the parent OGCM. Degradation was made horizontally over sets of four adjacent grid-cell squares for each vertical layer of the parent model. However, final resolution did not suffer because as a second step, after allowing the degraded model to reach equilibrium, we used its tracer output to reinitialize the parent model (at the original resolution). After reinitialization, the parent model must then be integrated only to a few hundred years before reaching equilibrium. To validate our degradation-integration technique (DEGINT), we compared {sup 14}C results from runs with and without this approach. Differences are less than 10 permille throughout 98.5% of the ocean volume. Predicted natural {sup 14}C appears reasonable over most of the ocean. In the Atlantic, modeled {Delta}{sup 14}C indicates that as observed, the North Atlantic Deep Water (NADW) fills the deep North Atlantic, and Antartic Intermediate Water (AAIW) infiltrates northward. (orig.) With 12 figs., 1 tab., 42 refs.

  12. Simulating coronal condensation dynamics in 3D

    Science.gov (United States)

    Moschou, S. P.; Keppens, R.; Xia, C.; Fang, X.

    2015-12-01

    We present numerical simulations in 3D settings where coronal rain phenomena take place in a magnetic configuration of a quadrupolar arcade system. Our simulation is a magnetohydrodynamic simulation including anisotropic thermal conduction, optically thin radiative losses, and parametrised heating as main thermodynamical features to construct a realistic arcade configuration from chromospheric to coronal heights. The plasma evaporation from chromospheric and transition region heights eventually causes localised runaway condensation events and we witness the formation of plasma blobs due to thermal instability, that evolve dynamically in the heated arcade part and move gradually downwards due to interchange type dynamics. Unlike earlier 2.5D simulations, in this case there is no large scale prominence formation observed, but a continuous coronal rain develops which shows clear indications of Rayleigh-Taylor or interchange instability, that causes the denser plasma located above the transition region to fall down, as the system moves towards a more stable state. Linear stability analysis is used in the non-linear regime for gaining insight and giving a prediction of the system's evolution. After the plasma blobs descend through interchange, they follow the magnetic field topology more closely in the lower coronal regions, where they are guided by the magnetic dips.

  13. NASA 3D Models: Global Hawk

    Data.gov (United States)

    National Aeronautics and Space Administration — The ability of the Global Hawk air vehicle to autonomously fly long distances and remain aloft for extended periods of time means that measuring, monitoring, and...

  14. Simulations. 3D nuclear reactions; Simulations. Reactions nucleaires en 3D

    Energy Technology Data Exchange (ETDEWEB)

    Deleurence, Guillaume

    2012-05-15

    At CEA Saclay, the research programme for the forth generation of nuclear reactors, named 'Astrid' (Advanced Sodium Technological Reactor for Industrial Demonstration) of the Direction of nuclear energy (DEN), uses 2D or 3D movies and a 16 m{sup 2} image wall for the display of simulation results. This digest paper focusses on the technological means used for the simulations: the Curie supercomputer designed by Bull and the images display device. (J.S.)

  15. 3D Model Optimization of Four-Facet Drill for 3D Drilling Simulation

    Directory of Open Access Journals (Sweden)

    Buranský Ivan

    2016-09-01

    Full Text Available The article is focused on optimization of four-facet drill for 3D drilling numerical modelling. For optimization, the process of reverse engineering by PowerShape software was used. The design of four-facet drill was created in NumrotoPlus software. The modified 3D model of the drill was used in the numerical analysis of cutting forces. Verification of the accuracy of 3D models for reverse engineering was implemented using the colour deviation maps. The CAD model was in the STEP format. For simulation software, 3D model in the STEP format is ideal. STEP is a solid model. Simulation software automatically splits the 3D model into finite elements. The STEP model was therefore more suitable than the STL model.

  16. Charge collection characterization of a 3D silicon radiation detector by using 3D simulations

    CERN Document Server

    Kalliopuska, J; Orava, R

    2007-01-01

    In 3D detectors, the electrodes are processed within the bulk of the sensor material. Therefore, the signal charge is collected independently of the wafer thickness and the collection process is faster due to shorter distances between the charge collection electrodes as compared to a planar detector structure. In this paper, 3D simulations are used to assess the performance of a 3D detector structure in terms of charge sharing, efficiency and speed of charge collection, surface charge, location of the primary interaction and the bias voltage. The measured current pulse is proposed to be delayed due to the resistance–capacitance (RC) product induced by the variation of the serial resistance of the pixel electrode depending on the depth of the primary interaction. Extensive simulations are carried out to characterize the 3D detector structures and to verify the proposed explanation for the delay of the current pulse. A method for testing the hypothesis experimentally is suggested.

  17. Global Value Chains from a 3D Printing Perspective

    DEFF Research Database (Denmark)

    Laplume, André O; Petersen, Bent; Pearce, Joshua M.

    2016-01-01

    This article outlines the evolution of additive manufacturing technology, culminating in 3D printing and presents a vision of how this evolution is affecting existing global value chains (GVCs) in production. In particular, we bring up questions about how this new technology can affect...... of whether in some industries diffusion of 3D printing technologies may change the role of multinational enterprises as coordinators of GVCs by inducing the engagement of a wider variety of firms, even households....

  18. 3D visualization of port simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Horsthemke, W. H.; Macal, C. M.; Nevins, M. R.

    1999-06-14

    Affordable and realistic three dimensional visualization technology can be applied to large scale constructive simulations such as the port simulation model, PORTSIM. These visualization tools enhance the experienced planner's ability to form mental models of how seaport operations will unfold when the simulation model is implemented and executed. They also offer unique opportunities to train new planners not only in the use of the simulation model but on the layout and design of seaports. Simulation visualization capabilities are enhanced by borrowing from work on interface design, camera control, and data presentation. Using selective fidelity, the designers of these visualization systems can reduce their time and efforts by concentrating on those features which yield the most value for their simulation. Offering the user various observational tools allows the freedom to simply watch or engage in the simulation without getting lost. Identifying the underlying infrastructure or cargo items with labels can provide useful information at the risk of some visual clutter. The PortVis visualization expands the PORTSIM user base which can benefit from the results provided by this capability, especially in strategic planning, mission rehearsal, and training. Strategic planners will immediately reap the benefits of seeing the impact of increased throughput visually without keeping track of statistical data. Mission rehearsal and training users will have an effective training tool to supplement their operational training exercises which are limited in number because of their high costs. Having another effective training modality in this visualization system allows more training to take place and more personnel to gain an understanding of seaport operations. This simulation and visualization training can be accomplished at lower cost than would be possible for the operational training exercises alone. The application of PORTSIM and PortVis will lead to more efficient

  19. Simulating the 3-D Structure of Titan's Upper Atmosphere

    Science.gov (United States)

    Bell, J. M.; Waite, H.; Westlake, J.; Magee, B.

    2009-05-01

    We present results from the 3-D Titan Global Ionosphere-Thermosphere Model (Bell et al [2009], PSS, in review). We show comparisons between simulated N2, CH4, and H2 density fields and the in-situ data from the Cassini Ion Neutral Mass Spectrometer (INMS). We describe the temperature and wind fields consistent with these density calculations. Variations with local time, longitude, and latitude will be addressed. Potential plasma heating sources can be estimated using the 1-D model of De La Haye et al [2007, 2008] and the impacts on the thermosphere of Titan can be assessed in a global sense in Titan-GITM. Lastly, we will place these findings within the context of recent work in modeling the 2-D structure of Titan's upper atmosphere (Mueller-Wodarg et al [2008]).

  20. 3D Coulomb balls: experiment and simulation

    International Nuclear Information System (INIS)

    Arp, O; Block, D; Bonitz, M; Fehske, H; Golubnychiy, V; Kosse, S; Ludwig, P; Melzer, A; Piel, A

    2005-01-01

    Spherically symmetric three-dimensional charged particle clusters are analyzed experimentally and theoretically. Based on accurate molecular dynamics simulations ground state configurations and energies with clusters for N ≤ 160 are presented which correct previous results of Hasse and Avilov [Phys. Rev. A 44, 4506 (1991)]. A complete table is given in the appendix. Further, the lowest metastable states are analyzed

  1. A STUDY ON USING 3D VISUALIZATION AND SIMULATION PROGRAM (OPTITEX 3D ON LEATHER APPAREL

    Directory of Open Access Journals (Sweden)

    Ork Nilay

    2016-05-01

    Full Text Available Leather is a luxury garment. Design, material, labor, fitting and time costs are very effective on the production cost of the consumer leather good. 3D visualization and simulation programs which are getting popular in textile industry can be used for material, labor and time saving in leather apparel. However these programs have a very limited use in leather industry because leather material databases are not sufficient as in textile industry. In this research, firstly material properties of leather and textile fabric were determined by using both textile and leather physical test methods, and interpreted and introduced in the program. Detailed measures of an experimental human body were measured from a 3D body scanner. An avatar was designed according to these measurements. Then a prototype dress was made by using Computer Aided Design-CAD program for designing the patterns. After the pattern making, OptiTex 3D visualization and simulation program was used to visualize and simulate the dresses. Additionally the leather and cotton fabric dresses were sewn in real life. Then the visual and real life dresses were compared and discussed. 3D virtual prototyping seems a promising potential in future manufacturing technologies by evaluating the fitting of garments in a simple and quick way, filling the gap between 3D pattern design and manufacturing, providing virtual demonstrations to customers.

  2. Fully Resolved Simulations of 3D Printing

    Science.gov (United States)

    Tryggvason, Gretar; Xia, Huanxiong; Lu, Jiacai

    2017-11-01

    Numerical simulations of Fused Deposition Modeling (FDM) (or Fused Filament Fabrication) where a filament of hot, viscous polymer is deposited to ``print'' a three-dimensional object, layer by layer, are presented. A finite volume/front tracking method is used to follow the injection, cooling, solidification and shrinking of the filament. The injection of the hot melt is modeled using a volume source, combined with a nozzle, modeled as an immersed boundary, that follows a prescribed trajectory. The viscosity of the melt depends on the temperature and the shear rate and the polymer becomes immobile as its viscosity increases. As the polymer solidifies, the stress is found by assuming a hyperelastic constitutive equation. The method is described and its accuracy and convergence properties are tested by grid refinement studies for a simple setup involving two short filaments, one on top of the other. The effect of the various injection parameters, such as nozzle velocity and injection velocity are briefly examined and the applicability of the approach to simulate the construction of simple multilayer objects is shown. The role of fully resolved simulations for additive manufacturing and their use for novel processes and as the ``ground truth'' for reduced order models is discussed.

  3. 3D FEM Simulation of Flank Wear in Turning

    Science.gov (United States)

    Attanasio, Aldo; Ceretti, Elisabetta; Giardini, Claudio

    2011-05-01

    This work deals with tool wear simulation. Studying the influence of tool wear on tool life, tool substitution policy and influence on final part quality, surface integrity, cutting forces and power consumption it is important to reduce the global process costs. Adhesion, abrasion, erosion, diffusion, corrosion and fracture are some of the phenomena responsible of the tool wear depending on the selected cutting parameters: cutting velocity, feed rate, depth of cut, …. In some cases these wear mechanisms are described by analytical models as a function of process variables (temperature, pressure and sliding velocity along the cutting surface). These analytical models are suitable to be implemented in FEM codes and they can be utilized to simulate the tool wear. In the present paper a commercial 3D FEM software has been customized to simulate the tool wear during turning operations when cutting AISI 1045 carbon steel with uncoated tungsten carbide tip. The FEM software was improved by means of a suitable subroutine able to modify the tool geometry on the basis of the estimated tool wear as the simulation goes on. Since for the considered couple of tool-workpiece material the main phenomena generating wear are the abrasive and the diffusive ones, the tool wear model implemented into the subroutine was obtained as combination between the Usui's and the Takeyama and Murata's models. A comparison between experimental and simulated flank tool wear curves is reported demonstrating that it is possible to simulate the tool wear development.

  4. Estimates of mercury flux into the United States from non-local and global sources : results from a 3-D CTM simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Drewniak, B. A.; Kotamarthi, V. R.; Streets, D.; Kim, M.; Crist, K.; Ohio Univ.

    2008-11-01

    The sensitivity of Hg concentration and deposition in the United States to emissions in China was investigated by using a global chemical transport model: Model for Ozone and Related Chemical Tracers (MOZART). Two forms of gaseous Hg were included in the model: elemental Hg (HG(0)) and oxidized or reactive Hg (HGO). We simulated three different emission scenarios to evaluate the model's sensitivity. One scenario included no emissions from China, while the others were based on different estimates of Hg emissions in China. The results indicated, in general, that when Hg emissions were included, HG(0) concentrations increased both locally and globally. Increases in Hg concentrations in the United States were greatest during spring and summer, by as much as 7%. Ratios of calculated concentrations of Hg and CO near the source region in eastern Asia agreed well with ratios based on measurements. Increases similar to those observed for HG(0) were also calculated for deposition of HGO. Calculated increases in wet and dry deposition in the United States were 5-7% and 5-9%, respectively. The results indicate that long-range transcontinental transport of Hg has a non-negligible impact on Hg deposition levels in the United States.

  5. Front instabilities and invasiveness of simulated 3D avascular tumors.

    Directory of Open Access Journals (Sweden)

    Nikodem J Poplawski

    2010-05-01

    Full Text Available We use the Glazier-Graner-Hogeweg model to simulate three-dimensional (3D, single-phenotype, avascular tumors growing in an homogeneous tissue matrix (TM supplying a single limiting nutrient. We study the effects of two parameters on tumor morphology: a diffusion-limitation parameter defined as the ratio of the tumor-substrate consumption rate to the substrate-transport rate, and the tumor-TM surface tension. This initial model omits necrosis and oxidative/hypoxic metabolism effects, which can further influence tumor morphology, but our simplified model still shows significant parameter dependencies. The diffusion-limitation parameter determines whether the growing solid tumor develops a smooth (noninvasive or fingered (invasive interface, as in our earlier two-dimensional (2D simulations. The sensitivity of 3D tumor morphology to tumor-TM surface tension increases with the size of the diffusion-limitation parameter, as in 2D. The 3D results are unexpectedly close to those in 2D. Our results therefore may justify using simpler 2D simulations of tumor growth, instead of more realistic but more computationally expensive 3D simulations. While geometrical artifacts mean that 2D sections of connected 3D tumors may be disconnected, the morphologies of 3D simulated tumors nevertheless correlate with the morphologies of their 2D sections, especially for low-surface-tension tumors, allowing the use of 2D sections to partially reconstruct medically-important 3D-tumor structures.

  6. Simulations of drift waves in 3D magnetic configurations

    International Nuclear Information System (INIS)

    Jost, G.

    2000-06-01

    Drift waves are commonly held responsible for anomalous transport in tokamak configurations and in particular for the anomalously high heat loss. The next generation of stellarators on the other hand are hoped to be characterized by a much smaller neo-classical transport and by particle confinement close to that of tokamaks. There is nevertheless a strong interest in the stellarator community to study the properties of drift waves in 3D magnetic configurations. To serve this interest we have developed the first global gyrokinetic code, EUTERPE, aimed at the investigation of linear drift wave stability in general toroidal geometry. The physical model assumes electrostatic waves and adiabatic electrons. EUTERPE is a particle-in-cell (PIC) code in which the gyrokinetic Poisson equation is discretized with the finite element method defined in the PEST -1 system of magnetic coordinates. The magnetic geometry is provided by the magnetohydrodynamic (MHD) equilibrium code VMEC. The complete 3D model has been successfully validated in toroidal axisymmetric and straight helical geometries and has permitted the first simulation of unstable global ITG driven modes in non-axisymmetric toroidal configurations. As a first application, two configurations have been studied, the Quasi-Axially symmetric Stellarator with three fields periods (QAS3) currently one system under consideration at the Princeton Plasma Physics Laboratory and the Helically Symmetric experiment (HSX) which has recently started operation at the University of Wisconsin. QAS3 is characterized by a tokamak-Iike field in the outer part of the torus. In this structure the drift waves are mainly affected by the magnetic shear and barely by the shape of the plasma. Also, the results are very close to those obtained for a tokamak. On the other hand, results for the HSX configuration, which is characterized by a dominant helical magnetic field, show a clear 3D effect, namely a strong toroidal variation of the drift wave

  7. Design of 3D simulation engine for oilfield safety training

    Science.gov (United States)

    Li, Hua-Ming; Kang, Bao-Sheng

    2015-03-01

    Aiming at the demand for rapid custom development of 3D simulation system for oilfield safety training, this paper designs and implements a 3D simulation engine based on script-driven method, multi-layer structure, pre-defined entity objects and high-level tools such as scene editor, script editor, program loader. A scripting language been defined to control the system's progress, events and operating results. Training teacher can use this engine to edit 3D virtual scenes, set the properties of entity objects, define the logic script of task, and produce a 3D simulation training system without any skills of programming. Through expanding entity class, this engine can be quickly applied to other virtual training areas.

  8. Global Value Chains from a 3D Printing Perspective

    DEFF Research Database (Denmark)

    Laplume, André O; Petersen, Bent; Pearce, Joshua M.

    2016-01-01

    This article outlines the evolution of additive manufacturing technology, culminating in 3D printing and presents a vision of how this evolution is affecting existing global value chains (GVCs) in production. In particular, we bring up questions about how this new technology can affect...... the geographic span and density of GVCs. Potentially, wider adoption of this technology has the potential to partially reverse the trend towards global specialization of production systems into elements that may be geographically dispersed and closer to the end users (localization). This leaves the question...

  9. Progress towards 3D black hole merger simulations

    International Nuclear Information System (INIS)

    Seidel, E.

    2001-01-01

    I review recent progress in 3D numerical relativity, focused on simulations involving black holes evolved with singularity avoiding slicings, but also touching on recent results in advanced techniques like black hole excision. After a long series of axisymmetric and perturbative studies of distorted black holes and black hole collisions, similar studies were carried out with full 3D codes. The results showed that such black hole simulations can be carried out extremely accurately, although instabilities plague the simulation at uncomfortably early times. However, new formulations of Einstein's equations allow much more stable 3D evolutions than ever before, enabling the first studies of 3D gravitational collapse to a black hole. With these new formulations, for example, it has been possible to perform the first detailed simulations of 3D grazing collisions of black holes with unequal mass, spin, and with orbital angular momentum. I discuss the 3D black hole physics that can now be studied, and prospects for the future, which look increasingly bright due to recent progress in formulations, black hole excision, new gauge conditions, and larger computers. Simulations may soon be able to provide information about the final plunge of two black holes, of relevance for gravitational wave astronomy. (author)

  10. An Evaluative Review of Simulated Dynamic Smart 3d Objects

    Science.gov (United States)

    Romeijn, H.; Sheth, F.; Pettit, C. J.

    2012-07-01

    Three-dimensional (3D) modelling of plants can be an asset for creating agricultural based visualisation products. The continuum of 3D plants models ranges from static to dynamic objects, also known as smart 3D objects. There is an increasing requirement for smarter simulated 3D objects that are attributed mathematically and/or from biological inputs. A systematic approach to plant simulation offers significant advantages to applications in agricultural research, particularly in simulating plant behaviour and the influences of external environmental factors. This approach of 3D plant object visualisation is primarily evident from the visualisation of plants using photographed billboarded images, to more advanced procedural models that come closer to simulating realistic virtual plants. However, few programs model physical reactions of plants to external factors and even fewer are able to grow plants based on mathematical and/or biological parameters. In this paper, we undertake an evaluation of plant-based object simulation programs currently available, with a focus upon the components and techniques involved in producing these objects. Through an analytical review process we consider the strengths and weaknesses of several program packages, the features and use of these programs and the possible opportunities in deploying these for creating smart 3D plant-based objects to support agricultural research and natural resource management. In creating smart 3D objects the model needs to be informed by both plant physiology and phenology. Expert knowledge will frame the parameters and procedures that will attribute the object and allow the simulation of dynamic virtual plants. Ultimately, biologically smart 3D virtual plants that react to changes within an environment could be an effective medium to visually represent landscapes and communicate land management scenarios and practices to planners and decision-makers.

  11. Simulator sickness analysis of 3D video viewing on passive 3D TV

    Science.gov (United States)

    Brunnström, K.; Wang, K.; Andrén, B.

    2013-03-01

    The MPEG 3DV project is working on the next generation video encoding standard and in this process a call for proposal of encoding algorithms was issued. To evaluate these algorithm a large scale subjective test was performed involving Laboratories all over the world. For the participating Labs it was optional to administer a slightly modified Simulator Sickness Questionnaire (SSQ) from Kennedy et al (1993) before and after the test. Here we report the results from one Lab (Acreo) located in Sweden. The videos were shown on a 46 inch film pattern retarder 3D TV, where the viewers were using polarized passive eye-glasses to view the stereoscopic 3D video content. There were 68 viewers participating in this investigation in ages ranges from 16 to 72, with one third females. The questionnaire was filled in before and after the test, with a viewing time ranging between 30 min to about one and half hour, which is comparable to a feature length movie. The SSQ consists of 16 different symptoms that have been identified as important for indicating simulator sickness. When analyzing the individual symptoms it was found that Fatigue, Eye-strain, Difficulty Focusing and Difficulty Concentrating were significantly worse after than before. SSQ was also analyzed according to the model suggested by Kennedy et al (1993). All in all this investigation shows a statistically significant increase in symptoms after viewing 3D video especially related to visual or Oculomotor system.

  12. 3D-printed tracheoesophageal puncture and prosthesis placement simulator.

    Science.gov (United States)

    Barber, Samuel R; Kozin, Elliott D; Naunheim, Matthew R; Sethi, Rosh; Remenschneider, Aaron K; Deschler, Daniel G

    A tracheoesophageal prosthesis (TEP) allows for speech after total laryngectomy. However, TEP placement is technically challenging, requiring a coordinated series of steps. Surgical simulators improve technical skills and reduce operative time. We hypothesize that a reusable 3-dimensional (3D)-printed TEP simulator will facilitate comprehension and rehearsal prior to actual procedures. The simulator was designed using Fusion360 (Autodesk, San Rafael, CA). Components were 3D-printed in-house using an Ultimaker 2+ (Ultimaker, Netherlands). Squid simulated the common tracheoesophageal wall. A Blom-Singer TEP (InHealth Technologies, Carpinteria, CA) replicated placement. Subjects watched an instructional video and completed pre- and post-simulation surveys. The simulator comprised 3D-printed parts: the esophageal lumen and superficial stoma. Squid was placed between components. Ten trainees participated. Significant differences existed between junior and senior residents with surveys regarding anatomy knowledge(p<0.05), technical details(p<0.01), and equipment setup(p<0.01). Subjects agreed that simulation felt accurate, and rehearsal raised confidence in future procedures. A 3D-printed TEP simulator is feasible for surgical training. Simulation involving multiple steps may accelerate technical skills and improve education. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Simulation and test of 3D silicon radiation detectors

    International Nuclear Information System (INIS)

    Fleta, C.; Pennicard, D.; Bates, R.; Parkes, C.; Pellegrini, G.; Lozano, M.; Wright, V.; Boscardin, M.; Dalla Betta, G.-F.; Piemonte, C.; Pozza, A.; Ronchin, S.; Zorzi, N.

    2007-01-01

    The work presented here is the result of the collaborative effort between the University of Glasgow, ITC-IRST (Trento) and IMB-CNM (Barcelona) in the framework of the CERN-RD50 Collaboration to produce 3D silicon radiation detectors and study their performance. This paper reports on two sets of 3D devices. IRST and CNM have fabricated a set of single-type column 3D detectors, which have columnar electrodes of the same doping type and an ohmic contact located at the backplane. Simulations of the device behaviour and electrical test results are presented. In particular, current-voltage, capacitance-voltage and charge collection efficiency measurements are reported. Other types of structures called double-sided 3D detectors are currently being fabricated at CNM. In these detectors the sets of n and p columns are made on opposite sides of the device. Electrical and technological simulations and first processing results are presented

  14. M3D project for simulation studies of plasmas

    International Nuclear Information System (INIS)

    Park, W.; Belova, E.V.; Fu, G.Y.; Sugiyama, L.E.

    1998-01-01

    The M3D (Multi-level 3D) project carries out simulation studies of plasmas of various regimes using multi-levels of physics, geometry, and mesh schemes in one code package. This paper and papers by Strauss, Sugiyama, and Belova in this workshop describe the project, and present examples of current applications. The currently available physics models of the M3D project are MHD, two-fluids, gyrokinetic hot particle/MHD hybrid, and gyrokinetic particle ion/two-fluid hybrid models. The code can be run with both structured and unstructured meshes

  15. Statistical 3D damage accumulation model for ion implant simulators

    CERN Document Server

    Hernandez-Mangas, J M; Enriquez, L E; Bailon, L; Barbolla, J; Jaraiz, M

    2003-01-01

    A statistical 3D damage accumulation model, based on the modified Kinchin-Pease formula, for ion implant simulation has been included in our physically based ion implantation code. It has only one fitting parameter for electronic stopping and uses 3D electron density distributions for different types of targets including compound semiconductors. Also, a statistical noise reduction mechanism based on the dose division is used. The model has been adapted to be run under parallel execution in order to speed up the calculation in 3D structures. Sequential ion implantation has been modelled including previous damage profiles. It can also simulate the implantation of molecular and cluster projectiles. Comparisons of simulated doping profiles with experimental SIMS profiles are presented. Also comparisons between simulated amorphization and experimental RBS profiles are shown. An analysis of sequential versus parallel processing is provided.

  16. Statistical 3D damage accumulation model for ion implant simulators

    International Nuclear Information System (INIS)

    Hernandez-Mangas, J.M.; Lazaro, J.; Enriquez, L.; Bailon, L.; Barbolla, J.; Jaraiz, M.

    2003-01-01

    A statistical 3D damage accumulation model, based on the modified Kinchin-Pease formula, for ion implant simulation has been included in our physically based ion implantation code. It has only one fitting parameter for electronic stopping and uses 3D electron density distributions for different types of targets including compound semiconductors. Also, a statistical noise reduction mechanism based on the dose division is used. The model has been adapted to be run under parallel execution in order to speed up the calculation in 3D structures. Sequential ion implantation has been modelled including previous damage profiles. It can also simulate the implantation of molecular and cluster projectiles. Comparisons of simulated doping profiles with experimental SIMS profiles are presented. Also comparisons between simulated amorphization and experimental RBS profiles are shown. An analysis of sequential versus parallel processing is provided

  17. Collaboration system for simulation using commercial Web3D

    International Nuclear Information System (INIS)

    Okamoto, Koji; Ohkubo, Kohei

    2004-01-01

    The Web-3D system has been widely used in the internet. It can show the 3D environment easily and friendly. In order to develop the network collaboration system, the Web-3D system is used as the front end of the visualization tool. The 3D geometries have been transferred from the server using HTTP with the viewpoint, one of the commercialized Web-3D. The simulation results are directly transferred to the client using the TCP/IP socket with JAVA. The viewpoint can be controlled by the JAVA, so the transferred simulation data are displayed on the web, in real-time. The multi-client system enables the visualization of the real-time simulation results with remote site. The same results are shown on the remote web site, simultaneously. This means the remote collaboration can be achievable for the real-time simulation. Also, the system has the feedback system, which control the simulation parameter remotely. In this prototype system, the key feature of the collaboration system are discussed using the viewpoint as the frontend. (author)

  18. Simulátor 3D tiskárny

    OpenAIRE

    Čillo, Vladimír

    2015-01-01

    Tato bakalářská práce se zabýva návrhem a implementací simulátoru 3D tiskárny v jazyce C++ s využitím knihovny Qt. Simulátor předpokládá tiskárnu založenou na nejrozšířenější metodě 3D tisku - Fused Deposition Modeling. Vstupem simulátoru je 3D model ve formátu STL. Pro daný 3D model simulátor poskytuje odhad celkové doby tisku. Součástí simulace je také vizualizace procesu 3D tisku. Výsledkem práce je přenositelný program testovaný pod operačními systémy Linux a Windows. Funkčnost simulátoru...

  19. 3d visualization of atomistic simulations on every desktop

    Science.gov (United States)

    Peled, Dan; Silverman, Amihai; Adler, Joan

    2013-08-01

    Once upon a time, after making simulations, one had to go to a visualization center with fancy SGI machines to run a GL visualization and make a movie. More recently, OpenGL and its mesa clone have let us create 3D on simple desktops (or laptops), whether or not a Z-buffer card is present. Today, 3D a la Avatar is a commodity technique, presented in cinemas and sold for home TV. However, only a few special research centers have systems large enough for entire classes to view 3D, or special immersive facilities like visualization CAVEs or walls, and not everyone finds 3D immersion easy to view. For maximum physics with minimum effort a 3D system must come to each researcher and student. So how do we create 3D visualization cheaply on every desktop for atomistic simulations? After several months of attempts to select commodity equipment for a whole room system, we selected an approach that goes back a long time, even predating GL. The old concept of anaglyphic stereo relies on two images, slightly displaced, and viewed through colored glasses, or two squares of cellophane from a regular screen/projector or poster. We have added this capability to our AViz atomistic visualization code in its new, 6.1 version, which is RedHat, CentOS and Ubuntu compatible. Examples using data from our own research and that of other groups will be given.

  20. 3d visualization of atomistic simulations on every desktop

    International Nuclear Information System (INIS)

    Peled, Dan; Silverman, Amihai; Adler, Joan

    2013-01-01

    Once upon a time, after making simulations, one had to go to a visualization center with fancy SGI machines to run a GL visualization and make a movie. More recently, OpenGL and its mesa clone have let us create 3D on simple desktops (or laptops), whether or not a Z-buffer card is present. Today, 3D a la Avatar is a commodity technique, presented in cinemas and sold for home TV. However, only a few special research centers have systems large enough for entire classes to view 3D, or special immersive facilities like visualization CAVEs or walls, and not everyone finds 3D immersion easy to view. For maximum physics with minimum effort a 3D system must come to each researcher and student. So how do we create 3D visualization cheaply on every desktop for atomistic simulations? After several months of attempts to select commodity equipment for a whole room system, we selected an approach that goes back a long time, even predating GL. The old concept of anaglyphic stereo relies on two images, slightly displaced, and viewed through colored glasses, or two squares of cellophane from a regular screen/projector or poster. We have added this capability to our AViz atomistic visualization code in its new, 6.1 version, which is RedHat, CentOS and Ubuntu compatible. Examples using data from our own research and that of other groups will be given

  1. 3D Simulation of Nano-Imprint Lithography

    DEFF Research Database (Denmark)

    Román Marín, José Manuel; Rasmussen, Henrik K.; Hassager, Ole

    2010-01-01

    A proof of concept study of the feasibility of fully three-dimensional (3D) time-dependent simulation of nano-imprint lithography of polymer melt, where the polymer is treated as a structured liquid, has been presented. Considering the flow physics of the polymer as a structured liquid, we have...

  2. 3D finite element simulation of optical modes in VCSELs

    OpenAIRE

    Rozova, M.; Pomplun, J.; Zschiedrich, L.; Schmidt, F.; Burger, S.

    2011-01-01

    We present a finite element method (FEM) solver for computation of optical resonance modes in VCSELs. We perform a convergence study and demonstrate that high accuracies for 3D setups can be attained on standard computers. We also demonstrate simulations of thermo-optical effects in VCSELs.

  3. NECTAR: Simulation and Visualization in a 3D Collaborative Environment

    NARCIS (Netherlands)

    Law, Y.W.; Chan, K.Y.

    For simulation and visualization in a 3D collaborative environment, an architecture called the Nanyang Experimental CollaboraTive ARchitecture (NECTAR) has been developed. The objective is to support multi-user collaboration in a virtual environment with an emphasis on cost-effectiveness and

  4. Magnetic flux pumping in 3D nonlinear magnetohydrodynamic simulations

    Science.gov (United States)

    Krebs, I.; Jardin, S. C.; Günter, S.; Lackner, K.; Hoelzl, M.; Strumberger, E.; Ferraro, N.

    2017-10-01

    A self-regulating magnetic flux pumping mechanism in tokamaks that maintains the core safety factor at q ≈1 , thus preventing sawteeth, is analyzed in nonlinear 3D magnetohydrodynamic simulations using the M3D-C1 code. In these simulations, the most important mechanism responsible for the flux pumping is that a saturated (m =1 ,n =1 ) quasi-interchange instability generates an effective negative loop voltage in the plasma center via a dynamo effect. It is shown that sawtoothing is prevented in the simulations if β is sufficiently high to provide the necessary drive for the (m =1 ,n =1 ) instability that generates the dynamo loop voltage. The necessary amount of dynamo loop voltage is determined by the tendency of the current density profile to centrally peak which, in our simulations, is controlled by the peakedness of the applied heat source profile.

  5. 3D numerical simulation of transient processes in hydraulic turbines

    International Nuclear Information System (INIS)

    Cherny, S; Chirkov, D; Lapin, V; Eshkunova, I; Bannikov, D; Avdushenko, A; Skorospelov, V

    2010-01-01

    An approach for numerical simulation of 3D hydraulic turbine flows in transient operating regimes is presented. The method is based on a coupled solution of incompressible RANS equations, runner rotation equation, and water hammer equations. The issue of setting appropriate boundary conditions is considered in detail. As an illustration, the simulation results for runaway process are presented. The evolution of vortex structure and its effect on computed runaway traces are analyzed.

  6. 3D numerical simulation of transient processes in hydraulic turbines

    Science.gov (United States)

    Cherny, S.; Chirkov, D.; Bannikov, D.; Lapin, V.; Skorospelov, V.; Eshkunova, I.; Avdushenko, A.

    2010-08-01

    An approach for numerical simulation of 3D hydraulic turbine flows in transient operating regimes is presented. The method is based on a coupled solution of incompressible RANS equations, runner rotation equation, and water hammer equations. The issue of setting appropriate boundary conditions is considered in detail. As an illustration, the simulation results for runaway process are presented. The evolution of vortex structure and its effect on computed runaway traces are analyzed.

  7. APROS 3-D core models for simulators and plant analyzers

    International Nuclear Information System (INIS)

    Puska, E.K.

    1999-01-01

    The 3-D core models of APROS simulation environment can be used in simulator and plant analyzer applications, as well as in safety analysis. The key feature of APROS models is that the same physical models can be used in all applications. For three-dimensional reactor cores the APROS models cover both quadratic BWR and PWR cores and the hexagonal lattice VVER-type cores. In APROS environment the user can select the number of flow channels in the core and either five- or six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the channel description have a decisive effect on the calculation time of the 3-D core model and thus just these selection make at present the major difference between a safety analysis model and a training simulator model. The paper presents examples of various types of 3-D LWR-type core descriptions for simulator and plant analyzer use and discusses the differences of calculation speed and physical results between a typical safety analysis model description and a real-time simulator model description in transients. (author)

  8. 3D simulation of CANDU reactor regulating system

    International Nuclear Information System (INIS)

    Venescu, B.; Zevedei, D.; Jurian, M.

    2013-01-01

    Present paper shows the evaluation of the performance of the 3-D modal synthesis based reactor kinetic model in a closed-loop environment in a MATLAB/SIMULINK based Reactor Regulating System (RRS) simulation platform. A notable advantage of the 3-D model is the level of details that it can reveal as compared to the coupled point kinetic model. Using the developed RRS simulation platform, the reactor internal behaviours can be revealed during load-following tests. The test results are also benchmarked against measurements from an existing (CANDU) power plant. It can be concluded that the 3-D reactor model produces more realistic view of the core neutron flux distribution, which is closer to the real plant measurements than that from a coupled point kinetic model. It is also shown that, through a vectorization process, the computational load of the 3-D model is comparable with that of the 14-zone coupled point kinetic model. Furthermore, the developed Graphical User Interface (GUI) software package for RRS implementation represents a user friendly and independent application environment for education training and industrial utilizations. (authors)

  9. Microbial Enhanced Oil Recovery: 3D Simulation with Gravity Effects

    DEFF Research Database (Denmark)

    Nielsen, Sidsel Marie; Jessen, K.; Shapiro, Alexander

    2010-01-01

    Microbial enhanced oil recovery (MEOR) utilizes the activity of microorganisms, where microorganisms simultaneously grow in a reservoir and convert substrate into recovery enhancing products (usually, surfactants). In order to predict the performance of a MEOR process, a simulation tool is required...... using an operator splitting technique. To the best of our knowledge, this has resulted in the first full 3D MEOR streamline simulator. For verification purposes, we compare results from our streamline MEOR simulator to those of a conventional finite difference approach for 1D and 2D displacement...

  10. 3D printing to simulate laparoscopic choledochal surgery.

    Science.gov (United States)

    Burdall, Oliver C; Makin, Erica; Davenport, Mark; Ade-Ajayi, Niyi

    2016-05-01

    Laparoscopic simulation has transformed skills acquisition for many procedures. However, realistic nonbiological simulators for complex reconstructive surgery are rare. Life-like tactile feedback is particularly difficult to reproduce. Technological innovations may contribute novel solutions to these shortages. We describe a hybrid model, harnessing 3D technology to simulate laparoscopic choledochal surgery for the first time. Digital hepatic anatomy images and standard laparoscopic trainer dimensions were employed to create an entry level laparoscopic choledochal surgery model. The information was fed into a 3D systems project 660pro with visijet pxl core powder to create a free standing liver mold. This included a cuboid portal in which to slot disposable hybrid components representing hepatic and pancreatic ducts and choledochal cyst. The mold was used to create soft silicone replicas with T28 resin and T5 fast catalyst. The model was assessed at a national pediatric surgery training day. The 10 delegates that trialed the simulation felt that the tactile likeness was good (5.6/10±1.71, 10=like the real thing), was not too complex (6.2/10±1.35; where 1=too simple, 10=too complicated), and generally very useful (7.36/10±1.57, 10=invaluable). 100% stated that they felt they could reproduce this in their own centers, and 100% would recommend this simulation to colleagues. Though this first phase choledochal cyst excision simulation requires further development, 3D printing provides a useful means of creating specific and detailed simulations for rare and complex operations with huge potential for development. Copyright © 2016. Published by Elsevier Inc.

  11. AxiSEM3D: a new fast method for global wave propagation in 3-D Earth models with undulating discontinuities

    Science.gov (United States)

    Leng, K.; Nissen-Meyer, T.; van Driel, M.; Al-Attar, D.

    2016-12-01

    We present a new, computationally efficient numerical method to simulate global seismic wave propagation in realistic 3-D Earth models with laterally heterogeneous media and finite boundary perturbations. Our method is a hybrid of pseudo-spectral and spectral element methods (SEM). We characterize the azimuthal dependence of 3-D wavefields in terms of Fourier series, such that the 3-D equations of motion reduce to an algebraic system of coupled 2-D meridional equations, which can be solved by a 2-D spectral element method (based on www.axisem.info). Computational efficiency of our method stems from lateral smoothness of global Earth models (with respect to wavelength) as well as axial singularity of seismic point sources, which jointly confine the Fourier modes of wavefields to a few lower orders. All boundary perturbations that violate geometric spherical symmetry, including Earth's ellipticity, topography and bathymetry, undulations of internal discontinuities such as Moho and CMB, are uniformly considered by means of a Particle Relabeling Transformation.The MPI-based high performance C++ code AxiSEM3D, is now available for forward simulations upon 3-D Earth models with fluid outer core, ellipticity, and both mantle and crustal structures. We show novel benchmarks for global wave solutions in 3-D mantle structures between our method and an independent, fully discretized 3-D SEM with remarkable agreement. Performance comparisons are carried out on three state-of-the-art tomography models, with seismic period going down to 5s. It is shown that our method runs up to two orders of magnitude faster than the 3-D SEM for such settings, and such computational advantage scales favourably with seismic frequency. By examining wavefields passing through hypothetical Gaussian plumes of varying sharpness, we identify in model-wavelength space the limits where our method may lose its advantage.

  12. Implementation of virtual models from sheet metal forming simulation into physical 3D colour models using 3D printing

    Science.gov (United States)

    Junk, S.

    2016-08-01

    Today the methods of numerical simulation of sheet metal forming offer a great diversity of possibilities for optimization in product development and in process design. However, the results from simulation are only available as virtual models. Because there are any forming tools available during the early stages of product development, physical models that could serve to represent the virtual results are therefore lacking. Physical 3D-models can be created using 3D-printing and serve as an illustration and present a better understanding of the simulation results. In this way, the results from the simulation can be made more “comprehensible” within a development team. This paper presents the possibilities of 3D-colour printing with particular consideration of the requirements regarding the implementation of sheet metal forming simulation. Using concrete examples of sheet metal forming, the manufacturing of 3D colour models will be expounded upon on the basis of simulation results.

  13. i3Drive, a 3D interactive driving simulator.

    Science.gov (United States)

    Ambroz, Miha; Prebil, Ivan

    2010-01-01

    i3Drive, a wheeled-vehicle simulator, can accurately simulate vehicles of various configurations with up to eight wheels in real time on a desktop PC. It presents the vehicle dynamics as an interactive animation in a virtual 3D environment. The application is fully GUI-controlled, giving users an easy overview of the simulation parameters and letting them adjust those parameters interactively. It models all relevant vehicle systems, including the mechanical models of the suspension, power train, and braking and steering systems. The simulation results generally correspond well with actual measurements, making the system useful for studying vehicle performance in various driving scenarios. i3Drive is thus a worthy complement to other, more complex tools for vehicle-dynamics simulation and analysis.

  14. RTS amplitudes in decananometer MOSFETs: 3-D simulation study

    OpenAIRE

    Asenov, A.; Balasubramaniam, R.; Brown, A.R.; Davies, J.H.

    2003-01-01

    In this paper we study the amplitudes of random telegraph signals (RTS) associated with the trapping of a single electron in defect states at the Si/SiO/sub 2/ interface of sub-100-nm (decananometer) MOSFETs employing three-dimensional (3-D) "atomistic" simulations. Both continuous doping charge and random discrete dopants in the active region of the MOSFETs are considered in the simulations. The dependence of the RTS amplitudes on the position of the trapped charge in the channel and on devi...

  15. 3D-finite element impact simulation on concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Heider, N.

    1989-12-15

    The analysis of impact processes is an interesting application of full 3D Finite Element calculations. This work presents a simulation of the penetration process of a Kinetic Energy projectile into a concrete target. Such a calculation requires an adequate FE model, especially a proper description of the crack opening process in front of the projectile. The aim is the prediction of the structural survival of the penetrator case with the help of an appropriate failure criterion. Also, the computer simulation allows a detailed analysis of the physical phenomena during impact. (orig.) With 4 refs., 14 figs.

  16. 3D numerical simulations of multiphase continental rifting

    Science.gov (United States)

    Naliboff, J.; Glerum, A.; Brune, S.

    2017-12-01

    Observations of rifted margin architecture suggest continental breakup occurs through multiple phases of extension with distinct styles of deformation. The initial rifting stages are often characterized by slow extension rates and distributed normal faulting in the upper crust decoupled from deformation in the lower crust and mantle lithosphere. Further rifting marks a transition to higher extension rates and coupling between the crust and mantle lithosphere, with deformation typically focused along large-scale detachment faults. Significantly, recent detailed reconstructions and high-resolution 2D numerical simulations suggest that rather than remaining focused on a single long-lived detachment fault, deformation in this phase may progress toward lithospheric breakup through a complex process of fault interaction and development. The numerical simulations also suggest that an initial phase of distributed normal faulting can play a key role in the development of these complex fault networks and the resulting finite deformation patterns. Motivated by these findings, we will present 3D numerical simulations of continental rifting that examine the role of temporal increases in extension velocity on rifted margin structure. The numerical simulations are developed with the massively parallel finite-element code ASPECT. While originally designed to model mantle convection using advanced solvers and adaptive mesh refinement techniques, ASPECT has been extended to model visco-plastic deformation that combines a Drucker Prager yield criterion with non-linear dislocation and diffusion creep. To promote deformation localization, the internal friction angle and cohesion weaken as a function of accumulated plastic strain. Rather than prescribing a single zone of weakness to initiate deformation, an initial random perturbation of the plastic strain field combined with rapid strain weakening produces distributed normal faulting at relatively slow rates of extension in both 2D and

  17. Reactive flow simulation in complex 3D geometries using the COM3D code

    International Nuclear Information System (INIS)

    Breitung, W.; Kotchourko, A.; Veser, A.; Scholtyssek, W.

    1999-01-01

    The COM3D code, under development at the Forschungszentrum Karlsruhe (FZK), is a 3-d CFD code to describe turbulent combustion phenomena in complex geometries. It is intended to be part of the advanced integral code system for containment analysis (INCA) which includes in addition GASFLOW for distribution calculations, V3D for slow combustion and DET3D for detonation analysis. COM3D uses a TVD-solver and optional models for turbulence, chemistry and thermodynamics. The hydrodynamic model considers mass, momentum and energy conservation. Advanced procedures were provided to facilitate grid-development for complex 3-d structures. COM3D was validated on experiments performed on different scales with generally good agreement for important physical quantities. The code was applied to combustion analysis of a large PWR. The initial conditions were obtained from a GASFLOW distribution analysis for a LOOP scenario. Results are presented concerning flame propagation and pressure evolution in the containment which clearly demonstrate the effects of internal structures, their influence on turbulence formation and consequences for local loads. (author)

  18. 3D integrated HYDRA simulations of hohlraums including fill tubes

    Science.gov (United States)

    Marinak, M. M.; Milovich, J.; Hammel, B. A.; Macphee, A. G.; Smalyuk, V. A.; Kerbel, G. D.; Sepke, S.; Patel, M. V.

    2017-10-01

    Measurements of fill tube perturbations from hydro growth radiography (HGR) experiments on the National Ignition Facility show spoke perturbations in the ablator radiating from the base of the tube. These correspond to the shadow of the 10 μm diameter glass fill tube cast by hot spots at early time. We present 3D integrated HYDRA simulations of these experiments which include the fill tube. Meshing techniques are described which were employed to resolve the fill tube structure and associated perturbations in the simulations. We examine the extent to which the specific illumination geometry necessary to accommodate a backlighter in the HGR experiment contributes to the spoke pattern. Simulations presented include high resolution calculations run on the Trinity machine operated by the Alliance for Computing at Extreme Scale (ACES) partnership. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

  19. Rigid body motion in stereo 3D simulation

    International Nuclear Information System (INIS)

    Zabunov, Svetoslav

    2010-01-01

    This paper addresses the difficulties experienced by first-grade students studying rigid body motion at Sofia University. Most quantities describing the rigid body are in relations that the students find hard to visualize and understand. They also lose the notion of cause-result relations between vector quantities, such as the relation between torque and angular momentum. Consequently, the understanding of physical laws and conservation principles in free rigid body motion is hampered. This paper presents the capabilities of a 3D simulation, which aims to clarify these questions to the students, who are taught mechanics in the general physics course. The rigid body motion simulations may be observed at http://ialms.net/sim/, and are intended to complement traditional learning practices, not replace them, as the author shares the opinion that no simulation may fully resemble reality.

  20. 3D hydrodynamic simulations of carbon burning in massive stars

    Science.gov (United States)

    Cristini, A.; Meakin, C.; Hirschi, R.; Arnett, D.; Georgy, C.; Viallet, M.; Walkington, I.

    2017-10-01

    We present the first detailed 3D hydrodynamic implicit large eddy simulations of turbulent convection of carbon burning in massive stars. Simulations begin with radial profiles mapped from a carbon-burning shell within a 15 M⊙ 1D stellar evolution model. We consider models with 1283, 2563, 5123, and 10243 zones. The turbulent flow properties of these carbon-burning simulations are very similar to the oxygen-burning case. We performed a mean field analysis of the kinetic energy budgets within the Reynolds-averaged Navier-Stokes framework. For the upper convective boundary region, we find that the numerical dissipation is insensitive to resolution for linear mesh resolutions above 512 grid points. For the stiffer, more stratified lower boundary, our highest resolution model still shows signs of decreasing sub-grid dissipation suggesting it is not yet numerically converged. We find that the widths of the upper and lower boundaries are roughly 30 per cent and 10 per cent of the local pressure scaleheights, respectively. The shape of the boundaries is significantly different from those used in stellar evolution models. As in past oxygen-shell-burning simulations, we observe entrainment at both boundaries in our carbon-shell-burning simulations. In the large Péclet number regime found in the advanced phases, the entrainment rate is roughly inversely proportional to the bulk Richardson number, RiB (∝RiB-α, 0.5 ≲ α ≲ 1.0). We thus suggest the use of RiB as a means to take into account the results of 3D hydrodynamics simulations in new 1D prescriptions of convective boundary mixing.

  1. MESYST, Simulation of 3-D Tracer Dispersion in Atmosphere

    International Nuclear Information System (INIS)

    Mastrangelo, V.; Mehilli, I.

    2000-01-01

    1 - Description of program or function: Mesyst code is used for the simulation of 3D tracer dispersion in atmosphere. Three packages are part of this system: Cre-topo: prepares the terrain data for the Mesyst. Noabl: code calculates three- dimensional free divergence wind fields over complex terrain. Pas: Computing of tracer concentrations and depositions on a given domain. 2 - Method of solution: NOABL - Line Over Relaxation + Special adaptation of Gauss procedure. PAS - Monte Carlo Method. 3 - Restrictions on the complexity of the problem: Computations: Mesh size: variable from some meters to some hundreds meters Mesh number: variable depending on available real data (some hundreds points on each directions)

  2. Simulation of current generation in a 3-D plasma model

    International Nuclear Information System (INIS)

    Tsung, F.S.; Dawson, J.M.

    1996-01-01

    Two wires carrying current in the same direction will attract each other, and two wires carrying current in the opposite direction will repel each other. Now, consider a test charge in a plasma. If the test charge carries current parallel to the plasma, then it will be pulled toward the plasma core, and if the test charge carries current anti-parallel to the plasma, then it will be pushed to the edge. The electromagnetic coupling between the plasma and a test charge (i.e., the A parallel circ v parallel term in the test charge's Hamiltonian) breaks the symmetry in the parallel direction, and gives rise to a diffusion coefficient which is dependent on the particle's parallel velocity. This is the basis for the open-quotes preferential lossclose quotes mechanism described in the work by Nunan et al. In our previous 2+1/2 D work, in both cylindrical and toroidal geometries, showed that if the plasma column is centrally fueled, then an initial current increases steadily. The results in straight, cylindrical plasmas showed that self generated parallel current arises without trapped particle or neoclassical diffusion, as assumed by the bootstrap theory. It suggests that the fundamental mechanism seems to be the conservation of particles canonical momenta in the direction of the ignorable coordinate. We have extended the simulation to 3D to verify the model put forth. A scalable 3D EM-PIC code, with a localized field-solver, has been implemented to run on a large class of parallel computers. On the 512-node SP2 at Cornell Theory Center, we have benchmarked the 2+1/2 D calculations using 32 grids in the previously ignored direction, and a 100-fold increase in the number of particles. Our preliminary results show good agreements between the 2+1/2 D and the 3D calculations. We will present our 3D results at the meeting

  3. 3D TCAD Simulation for Semiconductor Processes, Devices and Optoelectronics

    CERN Document Server

    Li, Simon

    2012-01-01

    Technology computer-aided design, or TCAD, is critical to today’s semiconductor technology and anybody working in this industry needs to know something about TCAD.  This book is about how to use computer software to manufacture and test virtually semiconductor devices in 3D.  It brings to life the topic of semiconductor device physics, with a hands-on, tutorial approach that de-emphasizes abstract physics and equations and emphasizes real practice and extensive illustrations.  Coverage includes a comprehensive library of devices, representing the state of the art technology, such as SuperJunction LDMOS, GaN LED devices, etc. Provides a vivid, internal view of semiconductor devices, through 3D TCAD simulation; Includes comprehensive coverage of  TCAD simulations for both optic and electronic devices, from nano-scale to high-voltage high-power devices; Presents material in a hands-on, tutorial fashion so that industry practitioners will find maximum utility; Includes a comprehensive library of devices, re...

  4. 3D PORFLO simulations of Loviisa steam generator

    International Nuclear Information System (INIS)

    Hovi, V.; Ilvonen, M.

    2010-01-01

    PORFLO is a 3-dimensional two-phase flow solver for porous media, developed at VTT originally by Jaakko Miettinen and now mainly by the author Ville Hovi. It is targeted at applications where 3D phenomena may be significant, but geometrical complexity does not allow for a CFD-style structure-fitted grid, such as steam generators and other heat exchangers, reactor cores or core debris beds. Basic features of PORFLO include staggered Cartesian grid and iterative solution of pressure and phase velocities (phase-coupled SIMPLE) based on 3D momentum equations, together with mass and energy equations, all for both liquid and vapour. A PORFLO model of the secondary side of a WWER-440 horizontal steam generator was developed and some preliminary simulations of its steady state operation were performed. To generate the necessary boundary condition on the primary tubes, an APROS system code model was used, from which a simple unidirectional transfer brings the tube surface temperatures to PORFLO. Feedwater is modelled by mass sources at the injection tube, with no consideration of its momentum. In the interphasial mass transfer, evaporation and condensation are considered in the bulk sense and due to the primary tubes. In momentum transfer, the interphasial drag and the drag caused by the tube bundles are modelled according to. Results of the PORFLO simulations presented here, typically in a 109 x 30 x 30 grid, include liquid and vapour velocities, void fractions and evaporation / condensation rates. Furthermore, some comparisons of PORFLO and Fluent results were made. (Authors)

  5. Coniferous Canopy BRF Simulation Based on 3-D Realistic Scene

    Science.gov (United States)

    Wang, Xin-yun; Guo, Zhi-feng; Qin, Wen-han; Sun, Guo-qing

    2011-01-01

    It is difficulties for the computer simulation method to study radiation regime at large-scale. Simplified coniferous model was investigate d in the present study. It makes the computer simulation methods such as L-systems and radiosity-graphics combined method (RGM) more powerf ul in remote sensing of heterogeneous coniferous forests over a large -scale region. L-systems is applied to render 3-D coniferous forest scenarios: and RGM model was used to calculate BRF (bidirectional refle ctance factor) in visible and near-infrared regions. Results in this study show that in most cases both agreed well. Meanwhiie at a tree and forest level. the results are also good.

  6. 3D numerical simulation and analysis of railgun gouging mechanism

    Directory of Open Access Journals (Sweden)

    Jin-guo Wu

    2016-04-01

    Full Text Available A gouging phenomenon with a hypervelocity sliding electrical contact in railgun not only shortens the rail lifetime but also affects the interior ballistic performance. In this paper, a 3-D numerical model was introduced to simulate and analyze the generation mechanism and evolution of the rail gouging phenomenon. The results show that a rail surface bulge is an important factor to induce gouging. High density and high pressure material flow on the contact surface, obliquely extruded into the rail when accelerating the armature to a high velocity, can produce gouging. Both controlling the bulge size to a certain range and selecting suitable materials for rail surface coating will suppress the formation of gouging. The numerical simulation had a good agreement with experiments, which validated the computing model and methodology are reliable.

  7. FDTD simulation of EM wave propagation in 3-D media

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.; Tripp, A.C. [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Geology and Geophysics

    1996-01-01

    A finite-difference, time-domain solution to Maxwell`s equations has been developed for simulating electromagnetic wave propagation in 3-D media. The algorithm allows arbitrary electrical conductivity and permittivity variations within a model. The staggered grid technique of Yee is used to sample the fields. A new optimized second-order difference scheme is designed to approximate the spatial derivatives. Like the conventional fourth-order difference scheme, the optimized second-order scheme needs four discrete values to calculate a single derivative. However, the optimized scheme is accurate over a wider wavenumber range. Compared to the fourth-order scheme, the optimized scheme imposes stricter limitations on the time step sizes but allows coarser grids. The net effect is that the optimized scheme is more efficient in terms of computation time and memory requirement than the fourth-order scheme. The temporal derivatives are approximated by second-order central differences throughout. The Liao transmitting boundary conditions are used to truncate an open problem. A reflection coefficient analysis shows that this transmitting boundary condition works very well. However, it is subject to instability. A method that can be easily implemented is proposed to stabilize the boundary condition. The finite-difference solution is compared to closed-form solutions for conducting and nonconducting whole spaces and to an integral-equation solution for a 3-D body in a homogeneous half-space. In all cases, the finite-difference solutions are in good agreement with the other solutions. Finally, the use of the algorithm is demonstrated with a 3-D model. Numerical results show that both the magnetic field response and electric field response can be useful for shallow-depth and small-scale investigations.

  8. Study, simulation and design of a 3D clinostat

    Science.gov (United States)

    Pavone, Valentina; Guarnieri, Vincenzo; Lobascio, Cesare; Soma, Aurelio; Bosso, Nicola; Lamantea, Matteo Maria

    High cost and limited number of physically executable experiments in space have introduced the need for ground simulation systems that enable preparing experiments to be carried out on board, identifying phenomena associated with the altered gravity conditions, and taking advantage of these conditions, as in Biotechnology. Among systems developed to simulate microgravity, especially for life sciences experiments, different types of clinostats were realized. This work deals with mechanical design of a three-dimensional clinostat and simulation of the dynamic behavior of the system by varying the operating parameters. The design and simulation phase was preceded by a careful analysis of the state of art and by the review of the most recent results, in particular from the major investigators of Life Sciences in Space. The mechanical design is quite innovative by adoption of a structure entirely in aluminum, which allows robustness while reducing the overall weight. The transmission system of motion has been optimized by means of brushless DC micro motors, light and compact, which helped to reduce weight, dimensions, power consumption and increase the reliability and durability of the system. The study of the dynamic behavior using SIMPACK, a multibody simulation software, led to results in line with those found in the most important and recent scientific publications. This model was also appropriately configured to represent any desired operating condition, and for eventual system scalability. It would be interesting to generate simulated hypogravity - e.g.: 0.38-g (Mars) or 0.17-g (Moon). This would allow to investigate how terrestrial life forms can grow in other planetary habitats, or to determine the gravity threshold response of different organisms. At the moment, such a system can only be achieved by centrifuges in real microgravity. We are confident that simulation and associated tests with our 3D clinostat can help adjusting the parameters allowing variable g

  9. Unsteady 3D flow simulations in cranial arterial tree

    Science.gov (United States)

    Grinberg, Leopold; Anor, Tomer; Madsen, Joseph; Karniadakis, George

    2008-11-01

    High resolution unsteady 3D flow simulations in major cranial arteries have been performed. Two cases were considered: 1) a healthy volunteer with a complete Circle of Willis (CoW); and 2) a patient with hydrocephalus and an incomplete CoW. Computation was performed on 3344 processors of the new half petaflop supercomputer in TACC. Two new numerical approaches were developed and implemented: 1) a new two-level domain decomposition method, which couples continuous and discontinuous Galerkin discretization of the computational domain; and 2) a new type of outflow boundary conditions, which imposes, in an accurate and computationally efficient manner, clinically measured flow rates. In the first simulation, a geometric model of 65 cranial arteries was reconstructed. Our simulation reveals a high degree of asymmetry in the flow at the left and right parts of the CoW and the presence of swirling flow in most of the CoW arteries. In the second simulation, one of the main findings was a high pressure drop at the right anterior communicating artery (PCA). Due to the incompleteness of the CoW and the pressure drop at the PCA, the right internal carotid artery supplies blood to most regions of the brain.

  10. 3-D simulation of hanging wall effect at dam site

    Science.gov (United States)

    Zhang, L.; Xu, Y.

    2017-12-01

    Hanging wall effect is one of the near fault effects. This paper focuses on the difference of the ground motions on the hanging wall side between the footwall side of the fault at dam site considering the key factors, such as actual topography, the rupture process. For this purpose, 3-D ground motions are numerically simulated by the spectrum element method (SEM), which takes into account the physical mechanism of generation and propagation of seismic waves. With the SEM model of 548 million DOFs, excitation and propagation of seismic waves are simulated to compare the difference between the ground motion on the hanging wall side and that on the footwall side. Take Dagangshan region located in China as an example, several seismogenic finite faults with different dip angle are simulated to investigate the hanging wall effect. Furthermore, by comparing the ground motions of the receiving points, the influence of several factors on hanging wall effect is investigated, such as the dip of the fault and the fault type (strike slip fault or dip-slip fault). The peak acceleration on the hanging wall side is obviously larger than those on the footwall side, which numerically evidences the hanging wall effect. Besides, the simulation shows that only when the dip is less than 70° does the hanging wall effect deserve attention.

  11. Massive parallel 3D PIC simulation of negative ion extraction

    Science.gov (United States)

    Revel, Adrien; Mochalskyy, Serhiy; Montellano, Ivar Mauricio; Wünderlich, Dirk; Fantz, Ursel; Minea, Tiberiu

    2017-09-01

    The 3D PIC-MCC code ONIX is dedicated to modeling Negative hydrogen/deuterium Ion (NI) extraction and co-extraction of electrons from radio-frequency driven, low pressure plasma sources. It provides valuable insight on the complex phenomena involved in the extraction process. In previous calculations, a mesh size larger than the Debye length was used, implying numerical electron heating. Important steps have been achieved in terms of computation performance and parallelization efficiency allowing successful massive parallel calculations (4096 cores), imperative to resolve the Debye length. In addition, the numerical algorithms have been improved in terms of grid treatment, i.e., the electric field near the complex geometry boundaries (plasma grid) is calculated more accurately. The revised model preserves the full 3D treatment, but can take advantage of a highly refined mesh. ONIX was used to investigate the role of the mesh size, the re-injection scheme for lost particles (extracted or wall absorbed), and the electron thermalization process on the calculated extracted current and plasma characteristics. It is demonstrated that all numerical schemes give the same NI current distribution for extracted ions. Concerning the electrons, the pair-injection technique is found well-adapted to simulate the sheath in front of the plasma grid.

  12. Colossal Tooling Design: 3D Simulation for Ergonomic Analysis

    Science.gov (United States)

    Hunter, Steve L.; Dischinger, Charles; Thomas, Robert E.; Babai, Majid

    2003-01-01

    The application of high-level 3D simulation software to the design phase of colossal mandrel tooling for composite aerospace fuel tanks was accomplished to discover and resolve safety and human engineering problems. The analyses were conducted to determine safety, ergonomic and human engineering aspects of the disassembly process of the fuel tank composite shell mandrel. Three-dimensional graphics high-level software, incorporating various ergonomic analysis algorithms, was utilized to determine if the process was within safety and health boundaries for the workers carrying out these tasks. In addition, the graphical software was extremely helpful in the identification of material handling equipment and devices for the mandrel tooling assembly/disassembly process.

  13. 3D fluid simulations of tokamak edge turbulence

    International Nuclear Information System (INIS)

    Zeiler, A.; Biskamp, D.; Drake, J.F.; Guzdar, P.N.

    1995-09-01

    3D simulations of drift resistive ballooning turbulence are presented. The turbulence is basically controlled by a parameter α, the ratio of the drift wave frequency to the ideal ballooning growth rate. If this parameters is small (α≤1, corresponding to Ohmic or L-mode plasmas), the system is dominated by ballooning turbulence, which is strongly peaked at the outside of the torus. If it is large (α≥1, corresponding to H-mode plasmas) field line curvature plays a minor role. The turbulence is nonlinearly sustained even if curvature is removed and all modes are linearly stable due to magnetic shear. In the nonlinear regime without curvature the system obeys a different scaling law compared to the low α regime. The transport scaling is discussed in both regimes and the implications for OH-, L-mode and H-mode transport are discussed. (orig.)

  14. Bioavailable atmospheric phosphorous supply to the global ocean: a 3-D global modeling study

    Science.gov (United States)

    Myriokefalitakis, Stelios; Nenes, Athanasios; Baker, Alex R.; Mihalopoulos, Nikolaos; Kanakidou, Maria

    2016-12-01

    The atmospheric cycle of phosphorus (P) is parameterized here in a state-of-the-art global 3-D chemistry transport model, taking into account primary emissions of total P (TP) and soluble P (DP) associated with mineral dust, combustion particles from natural and anthropogenic sources, bioaerosols, sea spray and volcanic aerosols. For the present day, global TP emissions are calculated to be roughly 1.33 Tg-P yr-1, with the mineral sources contributing more than 80 % to these emissions. The P solubilization from mineral dust under acidic atmospheric conditions is also parameterized in the model and is calculated to contribute about one-third (0.14 Tg-P yr-1) of the global DP atmospheric source. To our knowledge, a unique aspect of our global study is the explicit modeling of the evolution of phosphorus speciation in the atmosphere. The simulated present-day global annual DP deposition flux is 0.45 Tg-P yr-1 (about 40 % over oceans), showing a strong spatial and temporal variability. Present-day simulations of atmospheric P aerosol concentrations and deposition fluxes are satisfactory compared with available observations, indicating however an underestimate of about 70 % on current knowledge of the sources that drive the P atmospheric cycle. Sensitivity simulations using preindustrial (year 1850) anthropogenic and biomass burning emission scenarios showed a present-day increase of 75 % in the P solubilization flux from mineral dust, i.e., the rate at which P is converted into soluble forms, compared to preindustrial times, due to increasing atmospheric acidity over the last 150 years. Future reductions in air pollutants due to the implementation of air-quality regulations are expected to decrease the P solubilization flux from mineral dust by about 30 % in the year 2100 compared to the present day. Considering, however, that all the P contained in bioaerosols is readily available for uptake by marine organisms, and also accounting for all other DP sources, a total

  15. Plasma environment of Titan: a 3-D hybrid simulation study

    Directory of Open Access Journals (Sweden)

    S. Simon

    2006-05-01

    Full Text Available Titan possesses a dense atmosphere, consisting mainly of molecular nitrogen. Titan's orbit is located within the Saturnian magnetosphere most of the time, where the corotating plasma flow is super-Alfvénic, yet subsonic and submagnetosonic. Since Titan does not possess a significant intrinsic magnetic field, the incident plasma interacts directly with the atmosphere and ionosphere. Due to the characteristic length scales of the interaction region being comparable to the ion gyroradii in the vicinity of Titan, magnetohydrodynamic models can only offer a rough description of Titan's interaction with the corotating magnetospheric plasma flow. For this reason, Titan's plasma environment has been studied by using a 3-D hybrid simulation code, treating the electrons as a massless, charge-neutralizing fluid, whereas a completely kinetic approach is used to cover ion dynamics. The calculations are performed on a curvilinear simulation grid which is adapted to the spherical geometry of the obstacle. In the model, Titan's dayside ionosphere is mainly generated by solar UV radiation; hence, the local ion production rate depends on the solar zenith angle. Because the Titan interaction features the possibility of having the densest ionosphere located on a face not aligned with the ram flow of the magnetospheric plasma, a variety of different scenarios can be studied. The simulations show the formation of a strong magnetic draping pattern and an extended pick-up region, being highly asymmetric with respect to the direction of the convective electric field. In general, the mechanism giving rise to these structures exhibits similarities to the interaction of the ionospheres of Mars and Venus with the supersonic solar wind. The simulation results are in agreement with data from recent Cassini flybys.

  16. Virtual environment display for a 3D audio room simulation

    Science.gov (United States)

    Chapin, William L.; Foster, Scott

    1992-06-01

    Recent developments in virtual 3D audio and synthetic aural environments have produced a complex acoustical room simulation. The acoustical simulation models a room with walls, ceiling, and floor of selected sound reflecting/absorbing characteristics and unlimited independent localizable sound sources. This non-visual acoustic simulation, implemented with 4 audio ConvolvotronsTM by Crystal River Engineering and coupled to the listener with a Poihemus IsotrakTM, tracking the listener's head position and orientation, and stereo headphones returning binaural sound, is quite compelling to most listeners with eyes closed. This immersive effect should be reinforced when properly integrated into a full, multi-sensory virtual environment presentation. This paper discusses the design of an interactive, visual virtual environment, complementing the acoustic model and specified to: 1) allow the listener to freely move about the space, a room of manipulable size, shape, and audio character, while interactively relocating the sound sources; 2) reinforce the listener's feeling of telepresence into the acoustical environment with visual and proprioceptive sensations; 3) enhance the audio with the graphic and interactive components, rather than overwhelm or reduce it; and 4) serve as a research testbed and technology transfer demonstration. The hardware/software design of two demonstration systems, one installed and one portable, are discussed through the development of four iterative configurations. The installed system implements a head-coupled, wide-angle, stereo-optic tracker/viewer and multi-computer simulation control. The portable demonstration system implements a head-mounted wide-angle, stereo-optic display, separate head and pointer electro-magnetic position trackers, a heterogeneous parallel graphics processing system, and object oriented C++ program code.

  17. 3D Solar Null Point Reconnection MHD Simulations

    Science.gov (United States)

    Baumann, G.; Galsgaard, K.; Nordlund, Å.

    2013-06-01

    Numerical MHD simulations of 3D reconnection events in the solar corona have improved enormously over the last few years, not only in resolution, but also in their complexity, enabling more and more realistic modeling. Various ways to obtain the initial magnetic field, different forms of solar atmospheric models as well as diverse driving speeds and patterns have been employed. This study considers differences between simulations with stratified and non-stratified solar atmospheres, addresses the influence of the driving speed on the plasma flow and energetics, and provides quantitative formulas for mapping electric fields and dissipation levels obtained in numerical simulations to the corresponding solar quantities. The simulations start out from a potential magnetic field containing a null-point, obtained from a Solar and Heliospheric Observatory (SOHO) Michelson Doppler Imager (MDI) magnetogram magnetogram extrapolation approximately 8 hours before a C-class flare was observed. The magnetic field is stressed with a boundary motion pattern similar to - although simpler than - horizontal motions observed by SOHO during the period preceding the flare. The general behavior is nearly independent of the driving speed, and is also very similar in stratified and non-stratified models, provided only that the boundary motions are slow enough. The boundary motions cause a build-up of current sheets, mainly in the fan-plane of the magnetic null-point, but do not result in a flare-like energy release. The additional free energy required for the flare could have been partly present in non-potential form at the initial state, with subsequent additions from magnetic flux emergence or from components of the boundary motion that were not represented by the idealized driving pattern.

  18. Plasma environment of Titan: a 3-D hybrid simulation study

    Directory of Open Access Journals (Sweden)

    S. Simon

    2006-05-01

    Full Text Available Titan possesses a dense atmosphere, consisting mainly of molecular nitrogen. Titan's orbit is located within the Saturnian magnetosphere most of the time, where the corotating plasma flow is super-Alfvénic, yet subsonic and submagnetosonic. Since Titan does not possess a significant intrinsic magnetic field, the incident plasma interacts directly with the atmosphere and ionosphere. Due to the characteristic length scales of the interaction region being comparable to the ion gyroradii in the vicinity of Titan, magnetohydrodynamic models can only offer a rough description of Titan's interaction with the corotating magnetospheric plasma flow. For this reason, Titan's plasma environment has been studied by using a 3-D hybrid simulation code, treating the electrons as a massless, charge-neutralizing fluid, whereas a completely kinetic approach is used to cover ion dynamics. The calculations are performed on a curvilinear simulation grid which is adapted to the spherical geometry of the obstacle. In the model, Titan's dayside ionosphere is mainly generated by solar UV radiation; hence, the local ion production rate depends on the solar zenith angle. Because the Titan interaction features the possibility of having the densest ionosphere located on a face not aligned with the ram flow of the magnetospheric plasma, a variety of different scenarios can be studied. The simulations show the formation of a strong magnetic draping pattern and an extended pick-up region, being highly asymmetric with respect to the direction of the convective electric field. In general, the mechanism giving rise to these structures exhibits similarities to the interaction of the ionospheres of Mars and Venus with the supersonic solar wind. The simulation results are in agreement with data from recent Cassini flybys.

  19. 3D finite element simulation of TIG weld pool

    Science.gov (United States)

    Kong, X.; Asserin, O.; Gounand, S.; Gilles, P.; Bergheau, J. M.; Medale, M.

    2012-07-01

    The aim of this paper is to propose a three-dimensional weld pool model for the moving gas tungsten arc welding (GTAW) process, in order to understand the main factors that limit the weld quality and improve the productivity, especially with respect to the welding speed. Simulation is a very powerful tool to help in understanding the physical phenomena in the weld process. A 3D finite element model of heat and fluid flow in weld pool considering free surface of the pool and traveling speed has been developed for the GTAW process. Cast3M software is used to compute all the governing equations. The free surface of the weld pool is calculated by minimizing the total surface energy. The combined effects of surface tension gradient, buoyancy force, arc pressure, arc drag force to drive the fluid flow is included in our model. The deformation of the weld pool surface and the welding speed affect fluid flow, heat flow and thus temperature gradients and molten pool dimensions. Welding trials study is presented to compare our numerical results with macrograph of the molten pool.

  20. 3D space combat simulation game with artificial intelligence

    OpenAIRE

    Pernička, Václav

    2013-01-01

    The goal of this thesis is to design and implement a 3D space shooter with artifitial intelligence. This thesis includes theoretic analysis of space shooters, types of artifitial intelligence and assumptions important for developing in 3D space. The game also includes a simple artifitial intelligent player.

  1. BUSICO 3D: building simulation and control in unity 3D

    DEFF Research Database (Denmark)

    Fürst, Jonathan; Fierro, Gabe; Bonnet, Philippe

    2014-01-01

    In this demonstration, we present a novel system of building control and simulation focused on the integration of the physical and virtual worlds. Actuations and schedules can be manifested either in a physical space or in a virtualization of that space, allowing for more natural interactions...

  2. Identification of coronal heating events in 3D simulations

    Science.gov (United States)

    Kanella, Charalambos; Gudiksen, Boris V.

    2017-07-01

    Context. The solar coronal heating problem has been an open question in the science community since 1939. One of the proposed models for the transport and release of mechanical energy generated in the sub-photospheric layers and photosphere is the magnetic reconnection model that incorporates Ohmic heating, which releases a part of the energy stored in the magnetic field. In this model many unresolved flaring events occur in the solar corona, releasing enough energy to heat the corona. Aims: The problem with the verification and quantification of this model is that we cannot resolve small scale events due to limitations of the current observational instrumentation. Flaring events have scaling behavior extending from large X-class flares down to the so far unobserved nanoflares. Histograms of observable characteristics of flares show powerlaw behavior for energy release rate, size, and total energy. Depending on the powerlaw index of the energy release, nanoflares might be an important candidate for coronal heating; we seek to find that index. Methods: In this paper we employ a numerical three-dimensional (3D)-magnetohydrodynamic (MHD) simulation produced by the numerical code Bifrost, which enables us to look into smaller structures, and a new technique to identify the 3D heating events at a specific instant. The quantity we explore is the Joule heating, a term calculated directly by the code, which is explicitly correlated with the magnetic reconnection because it depends on the curl of the magnetic field. Results: We are able to identify 4136 events in a volume 24 × 24 × 9.5 Mm3 (I.e., 768 × 786 × 331 grid cells) of a specific snapshot. We find a powerlaw slope of the released energy per second equal to αP = 1.5 ± 0.02, and two powerlaw slopes of the identified volume equal to αV = 1.53 ± 0.03 and αV = 2.53 ± 0.22. The identified energy events do not represent all the released energy, but of the identified events, the total energy of the largest events

  3. Determination of material parameters by comparison of 3D simulations and 3D experiments

    DEFF Research Database (Denmark)

    Zhang, Jin

    microstructure and the measured microstructure in a global manner. The proposed method is demonstrated on a simple case to fit two material parameters: the liquid diffusion coefficient and the capillary length of a hypoeutectic Al-Cu alloy, and a complicated case to fit hundreds of material parameters......: the reduced grain boundary mobilities of pure iron. Results show that the proposed method is capable of providing reliable measurements of material parameters that are difficult to measure in traditional ways and can determine many - possibly all relevant - values of material parameters simultaneously...

  4. Transient simulations in WWER-1000-comparison between DYN3D-ATHLET and DYN3D-RELAP5

    International Nuclear Information System (INIS)

    Grundmann, U.; Kliem, S.; Kozmenkov, Y.; Mittag, S.; Rohde, U.; Weiss, F.P.

    2003-01-01

    Simulations of a real transient of an operating WWER-1000 power plant have been performed using DYN3D-ATHLET (Gru95) and DYN3D-RELAP5 (Koy01) code systems in the frame of activities aimed at a validation of the neutronic / thermal-hydraulic coupled codes. The transient initiated by a main coolant pump switching off, when three of the four main coolant pumps of the plant are in operation (scenario of the VALCO project) is chosen for the simulation. The same models of the plant (except the core nodalization) but two different libraries of macroscopic cross-sections have been used in compared calculations. Additionally, the compared code systems are based on the different / external and internal / coupling techniques. This paper contains a brief description of the coupled codes and the plant model as well as a comparison between the results from simulations (Authors)

  5. Simulation analysis of turbine blade in 3D printing aquarium

    Directory of Open Access Journals (Sweden)

    Chen Dyi-Cheng

    2017-01-01

    Full Text Available 3D printing of the flexibility is the most admirable place, no matter when or where, as long as the machine can make the abstract design of finished products or difficult to process the finished product printed out as a sample. And in the product design, through the 3D print out the entity, to more specific observation of the advantages and disadvantages of finished products, which shorten the time of many creative research and development, but also relatively reduce the defective factors. As in recent years, 3D printing technology is progressing, material adhesion, precision and parts of the degree of cooperation has increased, coupled with many parts taking into account the cost, production and other issues, and then let a lot of light load small parts or special parts choose to use 3D to print the finished product to replace. This study focuses on the plastic turbine blades that drive water in the aquarium, but the 3D printing is done by stacking. However, the general stress analysis software can set the material to analyze the deformation results of the force, nor the 3D to analyze the software. Therefore, this study first analyzes the deformation of turbine blade by software, and then verifies the situation of 3D printing turbine blade, and then compares the actual results of software analysis and 3D printing. The results can provide the future of 3D product consider the strength factor. The study found that the spiral blade design allows the force points to be dispersed to avoid hard focus.

  6. A global sustainability perspective on 3D printing technologies

    International Nuclear Information System (INIS)

    Gebler, Malte; Schoot Uiterkamp, Anton J.M.; Visser, Cindy

    2014-01-01

    Three-dimensional printing (3DP) represents a relative novel technology in manufacturing which is associated with potentially strong stimuli for sustainable development. Until now, research has merely assessed case study-related potentials of 3DP and described specific aspects of 3DP. This study represents the first comprehensive assessment of 3DP from a global sustainability perspective. It contains a qualitative assessment of 3DP-induced sustainability implications and quantifies changes in life cycle costs, energy and CO 2 emissions globally by 2025. 3DP is identified to cost-effectively lower manufacturing inputs and outputs in markets with low volume, customized and high-value production chains as aerospace and medical component manufacturing. This lowers energy use, resource demands and related CO 2 emissions over the entire product life cycle, induces changes in labour structures and generates shifts towards more digital and localized supply chains. The model calculations show that 3DP contains the potential to reduce costs by 170–593 billion US $, the total primary energy supply by 2.54–9.30 EJ and CO 2 emissions by 130.5–525.5 Mt by 2025. The great range within the saving potentials can be explained with the immature state of the technology and the associated uncertainties of predicting market and technology developments. The energy and CO 2 emission intensities of industrial manufacturing are reducible by maximally 5% through 3DP by 2025, as 3DP remains a niche technology. If 3DP was applicable to larger production volumes in consumer products or automotive manufacturing, it contains the (theoretical) potential to absolutely decouple energy and CO 2 emission from economic activity. - Highlights: • Global sustainability aspects of 3DP in manufacturing are assessed in two ways. • 3DP will strongly influence manufacturing in aerospace, medical components, tooling. • 3DP re-shifts production to consumer countries due to decreased labour costs.

  7. SYNRAD3D photon propagation and scattering simulations

    International Nuclear Information System (INIS)

    Dugan, G; Sagan, D

    2013-01-01

    The Bmad software library has been used very successfully at Cornell for modeling relativistic charged particles in storage rings and linacs. Associated with this library are a number of programs used for lattice design and analysis. Recently, as part of the CESRTA program, a new program that uses the Bmad library, called Synrad3D, has been developed to track synchrotron radiation photons generated in storage rings and linacs. The motivation for developing Synrad3D was to estimate the energy and position distribution of photon absorption sites, which are critical inputs to codes which model the growth of electron clouds. Synrad3D includes scattering from the vacuum chamber walls, based on X-ray data from an LBNL database for the smooth-surface reflectivity, and an analytical model for diffuse scattering from a surface with finite roughness. Synrad3D can handle any planar lattice and a wide variety of vacuum chamber profiles. In the following sections, the general approach used in Synrad3D will be described. The models used for the vacuum chamber, for specular reflection, and for diffuse reflection, will be described. Examples of the application to the program to predict the radiation environment in the CESRTA ring will be presented. Comparison of the scattering model with X-ray data from DAΦNE will be given. Finally, an application of the program to predict the radiation environment in the ILC damping ring will be shown

  8. Extracting 3D layout from a single image using global image structures.

    Science.gov (United States)

    Lou, Zhongyu; Gevers, Theo; Hu, Ninghang

    2015-10-01

    Extracting the pixel-level 3D layout from a single image is important for different applications, such as object localization, image, and video categorization. Traditionally, the 3D layout is derived by solving a pixel-level classification problem. However, the image-level 3D structure can be very beneficial for extracting pixel-level 3D layout since it implies the way how pixels in the image are organized. In this paper, we propose an approach that first predicts the global image structure, and then we use the global structure for fine-grained pixel-level 3D layout extraction. In particular, image features are extracted based on multiple layout templates. We then learn a discriminative model for classifying the global layout at the image-level. Using latent variables, we implicitly model the sublevel semantics of the image, which enrich the expressiveness of our model. After the image-level structure is obtained, it is used as the prior knowledge to infer pixel-wise 3D layout. Experiments show that the results of our model outperform the state-of-the-art methods by 11.7% for 3D structure classification. Moreover, we show that employing the 3D structure prior information yields accurate 3D scene layout segmentation.

  9. 3D simulation studies of tokamak plasmas using MHD and extended-MHD models

    International Nuclear Information System (INIS)

    Park, W.; Chang, Z.; Fredrickson, E.; Fu, G.Y.

    1996-01-01

    The M3D (Multi-level 3D) tokamak simulation project aims at the simulation of tokamak plasmas using a multi-level tokamak code package. Several current applications using MHD and Extended-MHD models are presented; high-β disruption studies in reversed shear plasmas using the MHD level MH3D code, ω *i stabilization and nonlinear island saturation of TAE mode using the hybrid particle/MHD level MH3D-K code, and unstructured mesh MH3D ++ code studies. In particular, three internal mode disruption mechanisms are identified from simulation results which agree which agree well with experimental data

  10. LED Virtual Simulation based on Web3D

    OpenAIRE

    Lilan Liu; Liu Han; Zhiqi Lin; Manping Li; Tao Yu

    2014-01-01

    Regarding to the high price and low market popularity of current LED indoor lighting products, a LED indoor lighting platform is proposed based on Web3D technology. The internet virtual reality technology is integrated and applied into the LED collaborative e-commerce website with Virtools. According to the characteristics of the LED indoor lighting products, this paper introduced the method to build encapsulated model and three characteristics of LED lighting: geometrical, optical and behavi...

  11. 3D Simulations of NIF Wetted Foam Experiments to Understand the Transition from 2D to 3D Implosion Behavior

    Science.gov (United States)

    Haines, Brian; Olson, Richard; Yi, Austin; Zylstra, Alex; Peterson, Robert; Bradley, Paul; Shah, Rahul; Wilson, Doug; Kline, John; Leeper, Ramon; Batha, Steve

    2017-10-01

    The high convergence ratio (CR) of layered Inertial Confinement Fusion capsule implosions contribute to high performance in 1D simulations yet make them more susceptible to hydrodynamic instabilities, contributing to the development of 3D flows. The wetted foam platform is an approach to hot spot ignition to achieve low-to-moderate convergence ratios in layered implosions on the NIF unobtainable using an ice layer. Detailed high-resolution modeling of these experiments in 2D and 3D, including all known asymmetries, demonstrates that 2D hydrodynamics explain capsule performance at CR 12 but become less suitable as the CR increases. Mechanisms for this behavior and detailed comparisons of simulations to experiments on NIF will be presented. To evaluate the tradeoff between increased instability and improved 1D performance, we present a full-scale wetted foam capsule design with 17 Simulations predict that, given currently achievable levels of asymmetry, their effects negate all advantages of increased CR.

  12. 3-D Hybrid Simulation of Quasi-Parallel Bow Shock and Its Effects on the Magnetosphere

    International Nuclear Information System (INIS)

    Lin, Y.; Wang, X.Y.

    2005-01-01

    A three-dimensional (3-D) global-scale hybrid simulation is carried out for the structure of the quasi-parallel bow shock, in particular the foreshock waves and pressure pulses. The wave evolution and interaction with the dayside magnetosphere are discussed. It is shown that diamagnetic cavities are generated in the turbulent foreshock due to the ion beam plasma interaction, and these compressional pulses lead to strong surface perturbations at the magnetopause and Alfven waves/field line resonance in the magnetosphere

  13. Non-linear 3D simulations of current-driven instabilities in jets

    International Nuclear Information System (INIS)

    Ivanovski, S.; Bonanno, A.

    2009-01-01

    We present global 3D nonlinear simulations of the Taylor instability in the presence of vertical fields. The initial configuration is in equilibrium, which is achieved by a pressure gradient or an external potential force. The non linear evolution of the system leads to a stable equilibrium with a current free toroidal field. We find the that presence of a vertical poloidal field stabilize the system if B φ ∼B z . The implication of our findings for the physics of astrophysical jets are discussed.

  14. 3-D numerical simulations of coronal loops oscillations

    Directory of Open Access Journals (Sweden)

    M. Selwa

    2009-10-01

    Full Text Available We present numerical results of 3-D MHD model of a dipole active region field containing a loop with a higher density than its surroundings. We study different ways of excitation of vertical kink oscillations by velocity perturbation: as an initial condition, and as an impulsive excitation with a pulse of a given position, duration, and amplitude. These properties are varied in the parametric studies. We find that the amplitude of vertical kink oscillations is significantly amplified in comparison to horizontal kink oscillations for exciters located centrally (symmetrically below the loop, but not if the exciter is located a significant distance to the side of the loop. This explains why the pure vertical kink mode is so rarely observed in comparison to the horizontally polarized one. We discuss the role of curved magnetic field lines and the pulse overlapping at one of the loop's footpoints in 3-D active regions (AR's on the excitation and the damping of slow standing waves. We find that footpoint excitation becomes more efficient in 3-D curved loops than in 2-D curved arcades and that slow waves can be excited within an interval of time that is comparable to the observed one wave-period due to the combined effect of the pulse inside and outside the loop. Additionally, we study the effect of AR topology on the excitation and trapping of loop oscillations. We find that a perturbation acting directly on a single loop excites oscillations, but results in an increased leakage compared to excitation of oscillations in an AR field by an external source.

  15. 3-D numerical simulations of coronal loops oscillations

    Directory of Open Access Journals (Sweden)

    M. Selwa

    2009-10-01

    Full Text Available We present numerical results of 3-D MHD model of a dipole active region field containing a loop with a higher density than its surroundings. We study different ways of excitation of vertical kink oscillations by velocity perturbation: as an initial condition, and as an impulsive excitation with a pulse of a given position, duration, and amplitude. These properties are varied in the parametric studies. We find that the amplitude of vertical kink oscillations is significantly amplified in comparison to horizontal kink oscillations for exciters located centrally (symmetrically below the loop, but not if the exciter is located a significant distance to the side of the loop. This explains why the pure vertical kink mode is so rarely observed in comparison to the horizontally polarized one. We discuss the role of curved magnetic field lines and the pulse overlapping at one of the loop's footpoints in 3-D active regions (AR's on the excitation and the damping of slow standing waves. We find that footpoint excitation becomes more efficient in 3-D curved loops than in 2-D curved arcades and that slow waves can be excited within an interval of time that is comparable to the observed one wave-period due to the combined effect of the pulse inside and outside the loop. Additionally, we study the effect of AR topology on the excitation and trapping of loop oscillations. We find that a perturbation acting directly on a single loop excites oscillations, but results in an increased leakage compared to excitation of oscillations in an AR field by an external source.

  16. 3d particle simulations on ultra short laser interaction

    Energy Technology Data Exchange (ETDEWEB)

    Nishihara, Katsunobu; Okamoto, Takashi; Yasui, Hidekazu [Osaka Univ., Suita (Japan). Inst. of Laser Engineering

    1998-03-01

    Two topics related to ultra short laser interaction with matter, linear and nonlinear high frequency conductivity of a solid density hydrogen plasma and anisotropic self-focusing of an intense laser in an overdense plasma, have been investigated with the use of 3-d particle codes. Frequency dependence of linear conductivity in a dense plasma is obtained, which shows anomalous conductivity near plasma frequency. Since nonlinear conductivity decreases with v{sub o}{sup -3}, where v{sub o} is a quivering velocity, an optimum amplitude exists leading to a maximum electron heating. Anisotropic self-focusing of a linear polarized intense laser is observed in an overdense plasma. (author)

  17. R3D Align web server for global nucleotide to nucleotide alignments of RNA 3D structures.

    Science.gov (United States)

    Rahrig, Ryan R; Petrov, Anton I; Leontis, Neocles B; Zirbel, Craig L

    2013-07-01

    The R3D Align web server provides online access to 'RNA 3D Align' (R3D Align), a method for producing accurate nucleotide-level structural alignments of RNA 3D structures. The web server provides a streamlined and intuitive interface, input data validation and output that is more extensive and easier to read and interpret than related servers. The R3D Align web server offers a unique Gallery of Featured Alignments, providing immediate access to pre-computed alignments of large RNA 3D structures, including all ribosomal RNAs, as well as guidance on effective use of the server and interpretation of the output. By accessing the non-redundant lists of RNA 3D structures provided by the Bowling Green State University RNA group, R3D Align connects users to structure files in the same equivalence class and the best-modeled representative structure from each group. The R3D Align web server is freely accessible at http://rna.bgsu.edu/r3dalign/.

  18. Methane Fluxes in West Siberia: 3-D Regional Model Simulation

    International Nuclear Information System (INIS)

    Jagovkina, S. V.; Karol, I. L.; Zubov, V. A.; Lagun, V. E.; Reshetnikov, A. I.; Rozanov, E. V.

    2001-01-01

    The West Siberian region is one of the main contributors of the atmospheric greenhouse gas methane due to the large areas of wetlands, rivers, lakes and numerous gas deposits situated there.But there are no reliable estimations of integral methane flux from this area into the atmosphere. For assessment of methane fluxes in West Siberia the specially constructed 3-D regional chemical transport model was applied. The 3-D distribution of methane is calculated on the basis of the current meteorological data fields(wind, temperature, geopotential) updated 4 times a day. The methane concentrations measured near the main gas fields of West Siberia in the summer season of 1999, were used for correction of methane flux intensity estimates obtained previously by comparison of measurements carried out in summer 1993 and 1996 with modelled methane mixing ratio distribution. This set of field and model experiments confirmed the preliminary conclusion about low leakage intensity: anthropogenic methane flux does not exceed 5-15% of total summer methane flux, estimated as 11-12 Mt CH 4 in summer from this region, in spite of the large areas of gas deposits located there

  19. 3D FE simulation of PCMI (Pellet-Cladding Mechanical Interaction) considering frictionless contact

    International Nuclear Information System (INIS)

    Seo, Sang-Kyu; Lee, Sung-Uk; Lee, Eun-Ho; Yang, Dong-Yol; Kim, Hyo-Chan; Yang, Yong-Sik

    2014-01-01

    The goal of this code is coupling every aspect of physical phenomenon. Monodimensional FE model has been made for METEOR. It is good to evaluate the global behavior in high burn up levels. However, the multi-dimensional PCI analysis code is necessary to precisely analyze the stress distribution especially in case of the crack analysis. CAST3M 3D finite element code has been developed considering thermo-mechanical interaction in detail for TOUTATIS code. The advanced multidimensional code called ALCYONE has been developed considering chemical-physics and thermomechanical aspects. Although there are many codes that analyze pellet and cladding interaction, it is difficult to consider every physical aspect. In this paper, pellet to cladding mechanical interaction in 3D has been simulated with frictionless contact using the developed module, which is written in FORTRANN90. In this paper, 3D PCMI FE model is simulated with frictionless contact and elastic deformation. From the frictionless contact analysis, the interfacial pressure has been calculated and then this is used to obtain the solid heat coefficient which is a main factor to analyze the thermal distribution

  20. Numerical Simulation of Effective Properties of 3D Piezoelectric Composites

    Directory of Open Access Journals (Sweden)

    Ri-Song Qin

    2014-01-01

    Full Text Available The prediction of the overall effective properties of fibre-reinforced piezocomposites has drawn much interest from investigators recently. In this work, an algorithm used in two-dimensional (2D analysis for calculating transversely isotropic material properties is developed. Since the finite element (FE meshing patterns on the opposite areas are the same, constraint equations can be applied directly to generate appropriate load. The numerical results derived using this model have found a good agreement with those in the literature. The 2D algorithm is then modified and improved in such a way that it is valid for three-dimensional (3D analysis in the case of random distributed shorts and inclusions. Linear interpolation of displacement field is employed to establish constraint equations of nodal displacements between two adjacent elements.

  1. Simple 3-D stimulus for motion parallax and its simulation.

    Science.gov (United States)

    Ono, Hiroshi; Chornenkyy, Yevgen; D'Amour, Sarah

    2013-01-01

    Simulation of a given stimulus situation should produce the same perception as the original. Rogers et al (2009 Perception 38 907-911) simulated Wheeler's (1982, PhD thesis, Rutgers University, NJ) motion parallax stimulus and obtained quite different perceptions. Wheeler's observers were unable to reliably report the correct direction of depth, whereas Rogers's were. With three experiments we explored the possible reasons for the discrepancy. Our results suggest that Rogers was able to see depth from the simulation partly due to his experience seeing depth with random dot surfaces.

  2. Tela global e oceano azul: cinema 3D, o caso Brasil

    Directory of Open Access Journals (Sweden)

    Andre Gatti

    2012-12-01

    Full Text Available A exibição de filmes de longa-metragem em 3D é a nova onda da indústria cinematográfica global. O que está acontecendo no Brasil? Quais problemas da implantação do 3D no país? Tudo ainda é muito recente, mas os resultados desta onda já podem ser percebidos.

  3. Single-sided sheet-to-tube spot welding investigated by 3D numerical simulations

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Chergui, Azeddine; Zhang, Wenqi

    The single-sided resistance spot welding process is analyzed by a 3D numerical study of sheet-to-tube joining. Finite element simulations are carried out in SORPAS® 3D. Two levels of electrode force and five levels of welding current are simulated. The overall effects of changing current and force...

  4. Enhancing Pre-Service Teachers' Awareness to Pupils' Test-Anxiety with 3D Immersive Simulation

    Science.gov (United States)

    Passig, David; Moshe, Ronit

    2008-01-01

    This study investigated whether participating in a 3D immersive virtual reality world simulating the experience of test-anxiety would affect preservice teachers' awareness to the phenomenon. Ninety subjects participated in this study, and were divided into three groups. The experimental group experienced a 3D immersive simulation which made…

  5. SIERRA - A 3-D device simulator for reliability modeling

    Science.gov (United States)

    Chern, Jue-Hsien; Arledge, Lawrence A., Jr.; Yang, Ping; Maeda, John T.

    1989-05-01

    SIERRA is a three-dimensional general-purpose semiconductor-device simulation program which serves as a foundation for investigating integrated-circuit (IC) device and reliability issues. This program solves the Poisson and continuity equations in silicon under dc, transient, and small-signal conditions. Executing on a vector/parallel minisupercomputer, SIERRA utilizes a matrix solver which uses an incomplete LU (ILU) preconditioned conjugate gradient square (CGS, BCG) method. The ILU-CGS method provides a good compromise between memory size and convergence rate. The authors have observed a 5x to 7x speedup over standard direct methods in simulations of transient problems containing highly coupled Poisson and continuity equations such as those found in reliability-oriented simulations. The application of SIERRA to parasitic CMOS latchup and dynamic random-access memory single-event-upset studies is described.

  6. Comparison of a 3-D DEM simulation with MRI data

    Science.gov (United States)

    Ng, Tang-Tat; Wang, Changming

    2001-04-01

    This paper presents a comparison of a granular material studied experimentally and numerically. Simple shear tests were performed inside the magnetic core of magnetic resonance imaging (MRI) equipment. Spherical pharmaceutical pills were used as the granular material, with each pill's centre location determined by MRI. These centre locations in the initial assembly were then used as the initial configuration in the numerical simulation using the discrete element method. The contact properties between pharmaceutical pills used in the numerical simulation were obtained experimentally. The numerical predication was compared with experimental data at both macroscopic and microscopic levels. Good agreement was found at both levels.

  7. Simulation of 3D-CRT treatment for lung cancer

    International Nuclear Information System (INIS)

    Thalhofer, Jardel L.; Silva, Ademir X. da; Junior, Juraci R.P.; Rebello, Wilson F.; Souza, Edmilson M.

    2013-01-01

    In radiotherapy treatment for lung cancer, occurs doses deposition in healthy organs. During the treatment planning are calculated some doses due to photons. This dose deposition in healthy organs could induce to the appearance of new cancers foci. The aim of this study was to analyze the equivalent doses in healthy organs of a patient treated by radiotherapy for lung cancer. In order to calculate the doses, was done a computer simulation of radiotherapy treatment for lung cancer, adopting database of the treatment performed by INCA. To perform the simulation was used several tools, among them, the radiation transport code MCNPX, in which was shaped the radiotherapy room and the head from the linear accelerator Varian 2300 C / D, the patient was simulated by Voxel male phantom in Rex,and the treatment protocol adopted considers a beam with energy of 6 MV focusing on three gantry tilt angles (0 deg, 180 deg and 45 deg). In addition, there was variation in the opening of the radiation field according to the angle of inclination. The results of this study point to the organs close to the irradiated area are predominantly affected by the dose due to photons, affecting organs from different body systems, such as esophagus, heart, thymus, spine and lymph nodes. The calculated values demonstrating that the angle of 0 deg was the most responsible for the deposit of unwanted dose. The results showed that the simulations in this paper is developed in accordance with the planning data described in different studies and literature. (author)

  8. Pseudo-spectral 3D simulations of streamers

    NARCIS (Netherlands)

    A. Luque (Alejandro); U. M. Ebert (Ute); C. Montijn (Carolynne-Sireeh); W. Hundsdorfer (Willem); J. Schmidt; M. Simek; S. Pekarek; V. Prukner

    2007-01-01

    textabstractA three-dimensional code for the simulation of streamers is introduced. The code is based on a fluid model for oxygen-nitrogen mixtures that includes drift, diffusion and attachement of electrons and creation of new charge carriers through impact ionization and photo-ionization. The

  9. Computer simulations of 3d Lorentzian quantum gravity

    NARCIS (Netherlands)

    Ambjørn, J.; Jurkiewicz, J.; Loll, R.

    2000-01-01

    We investigate the phase diagram of non-perturbative three-dimensional Lorentzian quantum gravity with the help of Monte Carlo simulations. The system has a first-order phase transition at a critical value kc 0 of the bare inverse gravitational coupling constant k0. For k0 > kc0 the system

  10. Hierarchical Approach to 'Atomistic' 3-D MOSFET Simulation

    Science.gov (United States)

    Asenov, Asen; Brown, Andrew R.; Davies, John H.; Saini, Subhash

    1999-01-01

    We present a hierarchical approach to the 'atomistic' simulation of aggressively scaled sub-0.1 micron MOSFET's. These devices are so small that their characteristics depend on the precise location of dopant atoms within them, not just on their average density. A full-scale three-dimensional drift-diffusion atomistic simulation approach is first described and used to verify more economical, but restricted, options. To reduce processor time and memory requirements at high drain voltage, we have developed a self-consistent option based on a solution of the current continuity equation restricted to a thin slab of the channel. This is coupled to the solution of the Poisson equation in the whole simulation domain in the Gummel iteration cycles. The accuracy of this approach is investigated in comparison to the full self-consistent solution. At low drain voltage, a single solution of the nonlinear Poisson equation is sufficient to extract the current with satisfactory accuracy. In this case, the current is calculated by solving the current continuity equation in a drift approximation only, also in a thin slab containing the MOSFET channel. The regions of applicability for the different components of this hierarchical approach are illustrated in example simulations covering the random dopant-induced threshold voltage fluctuations, threshold voltage lowering, threshold voltage asymmetry, and drain current fluctuations.

  11. 3D simulation studies of tokamak plasmas using MHD and extended-MHD models

    International Nuclear Information System (INIS)

    Park, W.; Chang, Z.; Fredrickson, E.; Fu, G.Y.; Pomphrey, N.; Sugiyama, L.E.

    1997-01-01

    The M3D (Multi-level 3D) tokamak simulation project aims at the simulation of tokamak plasmas using a multi-level tokamak code package. Several current applications using MHD and Extended-MHD models are presented; high-β disruption studies in reversed shear plasmas using the MHD level MH3D code, ω *i stabilization and nonlinear island rotation studies using the two-fluid level MH3D-T code, studies of nonlinear saturation of TAE modes using the hybrid particle/MHD level MH3D-K code, and unstructured mesh MH3D ++ code studies. In particular, three internal mode disruption mechanisms are identified from simulation results which agree well with experimental data

  12. Advanced 3D Photocathode Modeling and Simulations Final Report

    International Nuclear Information System (INIS)

    Dimitre A Dimitrov; David L Bruhwiler

    2005-01-01

    High brightness electron beams required by the proposed Next Linear Collider demand strong advances in photocathode electron gun performance. Significant improvement in the production of such beams with rf photocathode electron guns is hampered by the lack high-fidelity simulations. The critical missing piece in existing gun codes is a physics-based, detailed treatment of the very complex and highly nonlinear photoemission process

  13. 3D hybrid simulation of the Titan's plasma environment

    Science.gov (United States)

    Lipatov, Alexander; Sittler, Edward, Jr.; Hartle, Richard

    2007-11-01

    Titan plays an important role as a simulation laboratory for multiscale kinetic plasma processes which are key processes in space and laboratory plasmas. A development of multiscale combined numerical methods allows us to use more realistic plasma models at Titan. In this report, we describe a Particle-Ion--Fluid-Ion--Fluid--Electron method of kinetic ion-neutral simulation code. This method takes into account charge-exchange and photoionization processes. The model of atmosphere of Titan was based on a paper by Sittler, Hartle, Vinas et al., [2005]. The background ions H^+, O^+ and pickup ions H2^+, CH4^+ and N2^+ are described in a kinetic approximation, where the electrons are approximated as a fluid. In this report we study the coupling between background ions and pickup ions on the multiple space scales determined by the ion gyroradiis. The first results of such a simulation of the dynamics of ions near Titan are discussed in this report and compared with recent measurements made by the Cassini Plasma Spectrometer (CAPS, [Hartle, Sittler et al., 2006]). E C Sittler Jr., R E Hartle, A F Vinas, R E Johnson, H T Smith and I Mueller-Wodarg, J. Geophys. Res., 110, A09302, 2005.R E Hartle, E C Sittler, F M Neubauer, R E Johnson, et al., Planet. Space Sci., 54, 1211, 2006.

  14. A 3-D Global History from a Glober Identity ina Noncentric and Holistic Perspective

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    In modern times, global and world history has been understood, writtenand taught from either a national perspective or a regional/cultural/ideological one in the light of centrism such as West/Eurocentrism eversince it was created. The author argues, in a noncentric and holisticperspective, that nationalized global or world histories are nothingbut distorting mirrors full of pride and prejudice. It is argued that bothobjective global history and subjective global history are contingentresultants in a certain special and temporal context. In the early 21stcentury, the author heralds a globalization of global history and "GlobalHistorians of All Countries Unite!" He also suggests that it is necessaryfor a global historian to develop a glober identity beyond her/hisnational identity and that a reasonable and intelligible global historywhich is closer to the objective global history should be a 3-D globalhistory of the glober, by the glober, for the glober.

  15. [Accuracy of morphological simulation for orthognatic surgery. Assessment of a 3D image fusion software.

    Science.gov (United States)

    Terzic, A; Schouman, T; Scolozzi, P

    2013-08-06

    The CT/CBCT data allows for 3D reconstruction of skeletal and untextured soft tissue volume. 3D stereophotogrammetry technology has strongly improved the quality of facial soft tissue surface texture. The combination of these two technologies allows for an accurate and complete reconstruction. The 3D virtual head may be used for orthognatic surgical planning, virtual surgery, and morphological simulation obtained with a software dedicated to the fusion of 3D photogrammetric and radiological images. The imaging material include: a multi-slice CT scan or broad field CBCT scan, a 3D photogrammetric camera. The operative image processing protocol includes the following steps: 1) pre- and postoperative CT/CBCT scan and 3D photogrammetric image acquisition; 2) 3D image segmentation and fusion of untextured CT/CBCT skin with the preoperative textured facial soft tissue surface of the 3D photogrammetric scan; 3) image fusion of the pre- and postoperative CT/CBCT data set virtual osteotomies, and 3D photogrammetric soft tissue virtual simulation; 4) fusion of virtual simulated 3D photogrammetric and real postoperative images, and assessment of accuracy using a color-coded scale to measure the differences between the two surfaces. Copyright © 2013. Published by Elsevier Masson SAS.

  16. Photorealistic 3D omni-directional stereo simulator

    Science.gov (United States)

    Reiners, Dirk; Cruz-Neira, Carolina; Neumann, Carsten

    2015-03-01

    While a lot of areas in VR have made significant advances, visual rendering in VR is often not quite keeping up with the state of the art. There are many reasons for this, but one way to alleviate some of the issues is by using ray tracing instead of rasterization for image generation. Contrary to popular belief, ray tracing is a realistic, competitive technology nowadays. This paper looks at the pros and cons of using ray tracing and demonstrates the feasibility of employing it using the example of a helicopter flight simulator image generator.

  17. Application of computer virtual simulation technology in 3D animation production

    Science.gov (United States)

    Mo, Can

    2017-11-01

    In the continuous development of computer technology, the application system of virtual simulation technology has been further optimized and improved. It also has been widely used in various fields of social development, such as city construction, interior design, industrial simulation and tourism teaching etc. This paper mainly introduces the virtual simulation technology used in 3D animation. Based on analyzing the characteristics of virtual simulation technology, the application ways and means of this technology in 3D animation are researched. The purpose is to provide certain reference for the 3D effect promotion days after.

  18. Local-global alignment for finding 3D similarities in protein structures

    Science.gov (United States)

    Zemla, Adam T [Brentwood, CA

    2011-09-20

    A method of finding 3D similarities in protein structures of a first molecule and a second molecule. The method comprises providing preselected information regarding the first molecule and the second molecule. Comparing the first molecule and the second molecule using Longest Continuous Segments (LCS) analysis. Comparing the first molecule and the second molecule using Global Distance Test (GDT) analysis. Comparing the first molecule and the second molecule using Local Global Alignment Scoring function (LGA_S) analysis. Verifying constructed alignment and repeating the steps to find the regions of 3D similarities in protein structures.

  19. Plasma boundaries at Mars: a 3-D simulation study

    Directory of Open Access Journals (Sweden)

    A. Bößwetter

    2004-12-01

    Full Text Available The interaction of the solar wind with the ionosphere of planet Mars is studied using a three-dimensional hybrid model. Mars has only a weak intrinsic magnetic field, and consequently its ionosphere is directly affected by the solar wind. The gyroradii of the solar wind protons are in the range of several hundred kilometers and therefore comparable with the characteristic scales of the interaction region. Different boundaries emerge from the interaction of the solar wind with the continuously produced ionospheric heavy-ion plasma, which could be identified as a bow shock (BS, ion composition boundary (ICB and magnetic pile up boundary (MPB, where the latter both turn out to coincide. The simulation results regarding the shape and position of these boundaries are in good agreement with the measurements made by Phobos-2 and MGS spacecraft. It is shown that the positions of these boundaries depend essentially on the ionospheric production rate, the solar wind ram pressure, and the often unconsidered electron temperature of the ionospheric heavy ion plasma. Other consequences are rays of planetary plasma in the tail and heavy ion plasma clouds, which are stripped off from the dayside ICB region by some instability.

    Key words. Magnetospheric physics (solar wind interactions with unmagnetized bodies – Space plasma physics (discontinuities; numerical simulation studies

  20. [3D Virtual Reality Laparoscopic Simulation in Surgical Education - Results of a Pilot Study].

    Science.gov (United States)

    Kneist, W; Huber, T; Paschold, M; Lang, H

    2016-06-01

    The use of three-dimensional imaging in laparoscopy is a growing issue and has led to 3D systems in laparoscopic simulation. Studies on box trainers have shown differing results concerning the benefit of 3D imaging. There are currently no studies analysing 3D imaging in virtual reality laparoscopy (VRL). Five surgical fellows, 10 surgical residents and 29 undergraduate medical students performed abstract and procedural tasks on a VRL simulator using conventional 2D and 3D imaging in a randomised order. No significant differences between the two imaging systems were shown for students or medical professionals. Participants who preferred three-dimensional imaging showed significantly better results in 2D as wells as in 3D imaging. First results on three-dimensional imaging on box trainers showed different results. Some studies resulted in an advantage of 3D imaging for laparoscopic novices. This study did not confirm the superiority of 3D imaging over conventional 2D imaging in a VRL simulator. In the present study on 3D imaging on a VRL simulator there was no significant advantage for 3D imaging compared to conventional 2D imaging. Georg Thieme Verlag KG Stuttgart · New York.

  1. PIV measurement of the flow field in a domestic refrigerator model: Comparison with 3D simulations

    Energy Technology Data Exchange (ETDEWEB)

    Ben Amara, S.; Laguerre, O.; Flick, D. [UMR Genie Industriel Alimentaire (Cemagref-AgroParisTech-INRA) - Cemagref, Parc de Tourvoie, BP 44, 92185 Antony Cedex (France); Charrier-Mojtabi, M.-C.; Lartigue, B. [Universite Paul Sabatier, Laboratoire PHASE, E.A. 3208, 118 route de Narbonne, 31062 Toulouse Cedex 4 (France)

    2008-12-15

    PIV (particle image velocimetry) measurements of flow field due to natural convection in a parallelepipedic enclosure representing a domestic refrigerator model (scale 1) have been undertaken in order to determine the thickness of the hydrodynamic boundary layers and to study the flow motions depending on the boundary conditions applied on the vertical walls. One of the vertical walls is maintained at a negative and constant temperature either on the totality or on one part of its surface: this wall acts as the evaporator. The other walls are in contact with external air at constant temperature. The velocity measurements have been made in the symmetry plane of the enclosure. Unsteady recirculations have been observed at the bottom of the cavity. The influence of both the temperature and the dimension of the cold wall has been studied. Numerical simulations using CFD software (Fluent) have been then performed. In the numerical model, we assumed that the temperature of the evaporator is constant while an uniform global heat transfer coefficient has been used to describe the heat exchange with the external air at constant temperature. We considered laminar 3D flows and took into account the heat transfer by radiation between the different walls of the cavity. The results obtained with the 3D numerical simulations are in quite good agreement with the experimental airflow measurements using the PIV technique. (author)

  2. 3D code for simulations of fluid flows

    International Nuclear Information System (INIS)

    Skandera, D.

    2004-01-01

    In this paper, a present status in the development of the new numerical code is reported. The code is considered for simulations of fluid flows. The finite volume approach is adopted for solving standard fluid equations. They are treated in a conservative form to ensure a correct conservation of fluid quantities. Thus, a nonlinear hyperbolic system of conservation laws is numerically solved. The code uses the Eulerian description of the fluid and is designed as a high order central numerical scheme. The central approach employs no (approximate) Riemann solver and is less computational expensive. The high order WENO strategy is adopted in the reconstruction step to achieve results comparable with more accurate Riemann solvers. A combination of the central approach with an iterative solving of a local Riemann problem is tested and behaviour of such numerical flux is reported. An extension to three dimensions is implemented using a dimension by dimension approach, hence, no complicated dimensional splitting need to be introduced. The code is fully parallelized with the MPI library. Several standard hydrodynamic tests in one, two and three dimensions were performed and their results are presented. (author)

  3. Assessing extraterrestrial regolith material simulants for in-situ resource utilization based 3D printing

    OpenAIRE

    Goulas, A; Binner, JGP; Harris, RA; Friel, RJ

    2017-01-01

    This research paper investigates the suitability of ceramic multi-component materials, which are found on the Martian and Lunar surfaces, for 3D printing (aka Additive Manufacturing) of solid structures. 3D printing is a promising solution as part of the cutting edge field of future in situ space manufacturing applications. 3D printing of physical assets from simulated Martian and Lunar regolith was successfully performed during this work by utilising laser-based powder bed fusion equipment. ...

  4. 3D-Printed Craniosynostosis Model: New Simulation Surgical Tool.

    Science.gov (United States)

    Ghizoni, Enrico; de Souza, João Paulo Sant Ana Santos; Raposo-Amaral, Cassio Eduardo; Denadai, Rafael; de Aquino, Humberto Belém; Raposo-Amaral, Cesar Augusto; Joaquim, Andrei Fernandes; Tedeschi, Helder; Bernardes, Luís Fernando; Jardini, André Luiz

    2018-01-01

    Craniosynostosis is a complex disease once it involves deep anatomic perception, and a minor mistake during surgery can be fatal. The objective of this report is to present novel 3-dimensional-printed polyamide craniosynostosis models that can improve the understanding and treatment complex pathologies. The software InVesalius was used for segmentation of the anatomy image (from 3 patients between 6 and 9 months old). Afterward, the file was transferred to a 3-dimensional printing system and, with the use of an infrared laser, slices of powder PA 2200 were consecutively added to build a polyamide model of cranial bone. The 3 craniosynostosis models allowed fronto-orbital advancement, Pi procedure, and posterior distraction in the operating room environment. All aspects of the craniofacial anatomy could be shown on the models, as well as the most common craniosynostosis pathologic variations (sphenoid wing elevation, shallow orbits, jugular foramen stenosis). Another advantage of our model is its low cost, about 100 U.S. dollars or even less when several models are produced. Simulation is becoming an essential part of medical education for surgical training and for improving surgical safety with adequate planning. This new polyamide craniosynostosis model allowed the surgeons to have realistic tactile feedback on manipulating a child's bone and permitted execution of the main procedures for anatomic correction. It is a low-cost model. Therefore our model is an excellent option for training purposes and is potentially a new important tool to improve the quality of the management of patients with craniosynostosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Existence and uniqueness of global solutions for the modified anisotropic 3D Navier−Stokes equations

    KAUST Repository

    Bessaih, Hakima; Trabelsi, Saber; Zorgati, Hamdi

    2016-01-01

    obeys the Darcy−Forchheimer law instead of the classical Darcy law. We prove global in time existence and uniqueness of solutions without assuming the smallness condition on the initial data. This improves the result obtained for the classical 3D

  6. 3D Integration of MEMS and IC: Design, technology and simulations

    OpenAIRE

    Schjølberg-Henriksen, Kari

    2009-01-01

    * 3D integration: Opportunities and trends* e-CUBES: Tire pressure monitoring system (TPMS)* Package design including thermo-mechanical modeling* Technology development* Sensor packaging concept* Gold stud bump bonding* Device characterization and testing* Summary and outlook 3D Integration of MEMS and IC: Design, technology and simulations

  7. Comparison of 3D Echocardiogram-Derived 3D Printed Valve Models to Molded Models for Simulated Repair of Pediatric Atrioventricular Valves.

    Science.gov (United States)

    Scanlan, Adam B; Nguyen, Alex V; Ilina, Anna; Lasso, Andras; Cripe, Linnea; Jegatheeswaran, Anusha; Silvestro, Elizabeth; McGowan, Francis X; Mascio, Christopher E; Fuller, Stephanie; Spray, Thomas L; Cohen, Meryl S; Fichtinger, Gabor; Jolley, Matthew A

    2018-03-01

    Mastering the technical skills required to perform pediatric cardiac valve surgery is challenging in part due to limited opportunity for practice. Transformation of 3D echocardiographic (echo) images of congenitally abnormal heart valves to realistic physical models could allow patient-specific simulation of surgical valve repair. We compared materials, processes, and costs for 3D printing and molding of patient-specific models for visualization and surgical simulation of congenitally abnormal heart valves. Pediatric atrioventricular valves (mitral, tricuspid, and common atrioventricular valve) were modeled from transthoracic 3D echo images using semi-automated methods implemented as custom modules in 3D Slicer. Valve models were then both 3D printed in soft materials and molded in silicone using 3D printed "negative" molds. Using pre-defined assessment criteria, valve models were evaluated by congenital cardiac surgeons to determine suitability for simulation. Surgeon assessment indicated that the molded valves had superior material properties for the purposes of simulation compared to directly printed valves (p 3D echo-derived molded valves are a step toward realistic simulation of complex valve repairs but require more time and labor to create than directly printed models. Patient-specific simulation of valve repair in children using such models may be useful for surgical training and simulation of complex congenital cases.

  8. 3D flow simulation of liquid lead in the erosion test facility for ADS materials

    International Nuclear Information System (INIS)

    Muscher, Heinrich; Kieser, Martin; Weisenburger, Alfons; Mueller, Georg

    2009-01-01

    Future nuclear reactor concepts, such as GEN IV or ADS use liquid lead for neutron multiplication and coolant purposes. The design concepts assumes that the structural material is in contact with the liquid metal at temperatures up to 600 C and a flow rate of 20 m/s. Therefore a significant effect of liquid metal corrosion/erosion is expected. The paper describes the fluid dynamical simulation of the ADS erosion test facility. Earlier studies on the laminar flow modeling were completed by introduction of transient behavior and extended to 3D-models. The results for liquid lead should be transferable to LBE (lead bismuth eutectic). Further work has to include a mass transport model for modeling of the global isothermal erosion rate of the structural material dependent on time (for liquid lead and LBE).

  9. Recent advances in 3D computed tomography techniques for simulation and navigation in hepatobiliary pancreatic surgery.

    Science.gov (United States)

    Uchida, Masafumi

    2014-04-01

    A few years ago it could take several hours to complete a 3D image using a 3D workstation. Thanks to advances in computer science, obtaining results of interest now requires only a few minutes. Many recent 3D workstations or multimedia computers are equipped with onboard 3D virtual patient modeling software, which enables patient-specific preoperative assessment and virtual planning, navigation, and tool positioning. Although medical 3D imaging can now be conducted using various modalities, including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and ultrasonography (US) among others, the highest quality images are obtained using CT data, and CT images are now the most commonly used source of data for 3D simulation and navigation image. If the 2D source image is bad, no amount of 3D image manipulation in software will provide a quality 3D image. In this exhibition, the recent advances in CT imaging technique and 3D visualization of the hepatobiliary and pancreatic abnormalities are featured, including scan and image reconstruction technique, contrast-enhanced techniques, new application of advanced CT scan techniques, and new virtual reality simulation and navigation imaging. © 2014 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

  10. Simulação 3D de movimento ortodôntico 3D simulation of orthodontic tooth movement

    Directory of Open Access Journals (Sweden)

    Norman Duque Penedo

    2010-10-01

    Full Text Available OBJETIVO: desenvolver e validar, através do Método dos Elementos Finitos (MEF, um modelo numérico tridimensional (3D de um incisivo central superior para simular o movimento dentário. MÉTODOS: esse modelo contempla a unidade dentária, o osso alveolar e o ligamento periodontal. Permite a simulação dos diferentes movimentos dentários e a determinação dos centros de rotação e de resistência. Limita o movimento ao espaço periodontal, registrando a direção, quantificando o deslocamento dentário e as tensões iniciais no ligamento periodontal. RESULTADOS: a análise dos deslocamentos dentários e das áreas que recebem tensões iniciais possibilita determinar os tipos de movimentos dentários. Com base nas forças ortodônticas, é possível quantificar a intensidade das tensões em cada região do dente, do ligamento periodontal ou do osso alveolar. Com base nas tensões axiais ao longo do ligamento periodontal e da tensão capilar, é possível predizer, teoricamente, as regiões em que deve ocorrer a remodelação óssea. CONCLUSÃO: o modelo foi validado pela determinação do módulo de elasticidade do ligamento periodontal de forma compatível com dados experimentais existentes na literatura. Os métodos utilizados na construção do modelo permitiram a criação de um modelo completo para uma arcada dentária, o qual possibilita realizar variadas simulações que envolvem a mecânica ortodôntica.OBJECTIVE: To develop and validate a three-dimensional (3D numerical model of a maxillary central incisor to simulate tooth movement using the Finite Element Method (FEM. METHODS: This model encompasses the tooth, alveolar bone and periodontal ligament. It allows the simulation of different tooth movements and the establishment of centers of rotation and resistance. It limits the movement into the periodontal space, recording the direction, quantifying tooth displacement and initial stress in the periodontal ligament. RESULTS: By

  11. Fast globally optimal segmentation of 3D prostate MRI with axial symmetry prior.

    Science.gov (United States)

    Qiu, Wu; Yuan, Jing; Ukwatta, Eranga; Sun, Yue; Rajchl, Martin; Fenster, Aaron

    2013-01-01

    We propose a novel global optimization approach to segmenting a given 3D prostate T2w magnetic resonance (MR) image, which enforces the inherent axial symmetry of the prostate shape and simultaneously performs a sequence of 2D axial slice-wise segmentations with a global 3D coherence prior. We show that the proposed challenging combinatorial optimization problem can be solved globally and exactly by means of convex relaxation. With this regard, we introduce a novel coupled continuous max-flow model, which is dual to the studied convex relaxed optimization formulation and leads to an efficient multiplier augmented algorithm based on the modern convex optimization theory. Moreover, the new continuous max-flow based algorithm was implemented on GPUs to achieve a substantial improvement in computation. Experimental results using public and in-house datasets demonstrate great advantages of the proposed method in terms of both accuracy and efficiency.

  12. Analysis of PKP scattering using mantle mixing simulations and axisymmetric 3D waveforms

    Science.gov (United States)

    Haugland, Samuel M.; Ritsema, Jeroen; van Keken, Peter E.; Nissen-Meyer, Tarje

    2018-03-01

    The scattering of PKP waves in the lower mantle produces isolated signals before the PKIKP phase. We explore whether these so-called PKIKP precursors can be related to wave scattering off mid ocean ridge basalt (MORB) fragments that have been advected in the deep mantle throughout geologic time. We construct seismic models of small-scale (>20 km) heterogeneity in the lower mantle informed by mantle mixing simulations from Brandenburg et al. (2008) and generate PKIKP precursors using 3D, axisymmetric waveform simulations up to 0.75 Hz. We consider two end-member geodynamic models with fundamentally different distributions of MORB in the lower mantle. Our results suggest that the accumulation of MORB at the base of the mantle is a viable hypothesis for the origin of PKP scattering. We find that the strength of the PKIKP precursor amplitudes is consistent with P wave speed heterogeneity of 0.1-0.2%, as reported previously. The radial distribution of MORB has a profound effect on the strength of PKIKP precursors. Simulation of PKIKP precursors for models with an increasing MORB concentration in the lowermost 500 km of the mantle appears to reproduce most accurately the strength of PKIKP precursors in Global Seismic Network waveforms. These models assume that MORB has an excess density of at least 7%. Additional simulations of more complex geodynamic models will better constrain the geodynamic conditions to explain the significant variability of PKP scattering strength.

  13. Optimal design of wind barriers using 3D computational fluid dynamics simulations

    Science.gov (United States)

    Fang, H.; Wu, X.; Yang, X.

    2017-12-01

    Desertification is a significant global environmental and ecological problem that requires human-regulated control and management. Wind barriers are commonly used to reduce wind velocity or trap drifting sand in arid or semi-arid areas. Therefore, optimal design of wind barriers becomes critical in Aeolian engineering. In the current study, we perform 3D computational fluid dynamics (CFD) simulations for flow passing through wind barriers with different structural parameters. To validate the simulation results, we first inter-compare the simulated flow field results with those from both wind-tunnel experiments and field measurements. Quantitative analyses of the shelter effect are then conducted based on a series of simulations with different structural parameters (such as wind barrier porosity, row numbers, inter-row spacing and belt schemes). The results show that wind barriers with porosity of 0.35 could provide the longest shelter distance (i.e., where the wind velocity reduction is more than 50%) thus are recommended in engineering designs. To determine the optimal row number and belt scheme, we introduce a cost function that takes both wind-velocity reduction effects and economical expense into account. The calculated cost function show that a 3-row-belt scheme with inter-row spacing of 6h (h as the height of wind barriers) and inter-belt spacing of 12h is the most effective.

  14. Magneto-Hydrodynamic Simulations of a Magnetic Flux Compression Generator Using ALE3D

    Science.gov (United States)

    2017-07-01

    3 Fig. 3 Half- plane view of the geometry used in ALE3D simulation showing the materials...to LLNL’s SESAME data.8 Fig. 3 Half- plane view of the geometry used in ALE3D simulation showing the materials There are 2 broad approaches to...of mesh can be time- consuming . Since MFCGs have a cylindrical geometry, a high-resolution mesh is not required; one can use a conformal mesh and

  15. 3D Core Model for simulation of nuclear power plants: Simulation requirements, model features, and validation

    International Nuclear Information System (INIS)

    Zerbino, H.

    1999-01-01

    In 1994-1996, Thomson Training and Simulation (TT and S) earned out the D50 Project, which involved the design and construction of optimized replica simulators for one Dutch and three German Nuclear Power Plants. It was recognized early on that the faithful reproduction of the Siemens reactor control and protection systems would impose extremely stringent demands on the simulation models, particularly the Core physics and the RCS thermohydraulics. The quality of the models, and their thorough validation, were thus essential. The present paper describes the main features of the fully 3D Core model implemented by TT and S, and its extensive validation campaign, which was defined in extremely positive collaboration with the Customer and the Core Data suppliers. (author)

  16. Numerical simulation of 3D backward facing step flows at various Reynolds numbers

    Directory of Open Access Journals (Sweden)

    Louda Petr

    2015-01-01

    Full Text Available The work deals with the numerical simulation of 3D turbulent flow over backward facing step in a narrow channel. The mathematical model is based on the RANS equations with an explicit algebraic Reynolds stress model (EARSM. The numerical method uses implicit finite volume upwind discretization. While the eddy viscosity models fail in predicting complex 3D flows, the EARSM model is shown to provide results which agree well with experimental PIV data. The reference experimental data provide the 3D flow field. The simulations are compared with experiment for 3 values of Reynolds number.

  17. [Non-biological 3D printed simulator for training in percutaneous nephro- lithotripsy].

    Science.gov (United States)

    Alyaev, Yu G; Sirota, E S; Bezrukov, E A; Ali, S Kh; Bukatov, M D; Letunovskiy, A V; Byadretdinov, I Sh

    2018-03-01

    To develop a non-biological 3D printed simulator for training and preoperative planning in percutaneous nephrolithotripsy (PCNL), which allows doctors to master and perform all stages of the operation under ultrasound and fluoroscopy guidance. The 3D model was constructed using multislice spiral computed tomography (MSCT) images of a patient with staghorn urolithiasis. The MSCT data were processed and used to print the model. The simulator consisted of two parts: a non-biological 3D printed soft model of a kidney with reproduced intra-renal vascular and collecting systems and a printed 3D model of a human body. Using this 3D printed simulator, PCNL was performed in the interventional radiology operating room under ultrasound and fluoroscopy guidance. The designed 3D printed model of the kidney completely reproduces the individual features of the intra-renal structures of the particular patient. During the training, all the main stages of PCNL were performed successfully: the puncture, dilation of the nephrostomy tract, endoscopic examination, intra-renal lithotripsy. Our proprietary 3D-printed simulator is a promising development in the field of endourologic training and preoperative planning in the treatment of complicated forms of urolithiasis.

  18. 3D Printed Surgical Instruments Evaluated by a Simulated Crew of a Mars Mission.

    Science.gov (United States)

    Wong, Julielynn Y; Pfahnl, Andreas C

    2016-09-01

    The first space-based fused deposition modeling (FDM) 3D printer became operational in 2014. This study evaluated whether Mars simulation crewmembers of the Hawai'i Space Exploration Analog and Simulation (HI-SEAS) II mission with no prior surgical experience could utilize acrylonitrile butadiene styrene (ABS) thermoplastic surgical instruments FDM 3D printed on Earth to complete simulated surgical tasks. This study sought to examine the feasibility of using 3D printed surgical tools when the primary crew medical officer is incapacitated and the back-up crew medical officer must conduct a surgical procedure during a simulated extended space mission. During a 4 mo duration ground-based analog mission, five simulation crewmembers with no prior surgical experience completed 16 timed sets of simulated prepping, draping, incising, and suturing tasks to evaluate the relative speed of using four ABS thermoplastic instruments printed on Earth compared to conventional instruments. All four simulated surgical tasks were successfully performed using 3D printed instruments by Mars simulation crewmembers with no prior surgical experience. There was no substantial difference in time to completion of simulated tasks with control vs. 3D printed sponge stick, towel clamp, scalpel handle, and toothed forceps. These limited findings support further investigation into the creation of an onboard digital catalog of validated 3D printable surgical instrument design files to support autonomous, crew-administered healthcare on Mars missions. Future work could include addressing sterility, biocompatibility, and having astronaut crew medical officers test a wider range of surgical instruments printed in microgravity during actual surgical procedures. Wong JY, Pfahnl AC. 3D printed surgical instruments evaluated by a simulated crew of a Mars mission. Aerosp Med Hum Perform. 2016; 87(9):806-810.

  19. The Effects of 3D Computer Simulation on Biology Students' Achievement and Memory Retention

    Science.gov (United States)

    Elangovan, Tavasuria; Ismail, Zurida

    2014-01-01

    A quasi experimental study was conducted for six weeks to determine the effectiveness of two different 3D computer simulation based teaching methods, that is, realistic simulation and non-realistic simulation on Form Four Biology students' achievement and memory retention in Perak, Malaysia. A sample of 136 Form Four Biology students in Perak,…

  20. 3D Modeling and Simulation for Electromagnetic Non-Destructive Testing- Problems and Limitations

    International Nuclear Information System (INIS)

    Ilham Mukriz Zainal Abidin; Nurul Ain Ahmad Latif

    2011-01-01

    Non-Destructive Testing (NDT) plays a critical role in nuclear power plants (NPPs) for life cycle management; such testing requires specialists with various NDT related expertise with specific equipment. This paper will discuss the importance of 3D modeling and simulation for electromagnetic NDT for critical and complex components in terms of engineering reasoning and physical trials. Results from simulation are presented which show the link established between the measurements and information relating to defects, such as 3D shape, size and location, which facilitates not only forward problem but also inverse modeling involving experimental system specification and configuration; and pattern recognition for 3D defect information. Subsequently, the problems and limitations pertinent to 3D modeling and simulation are then highlighted and areas of improvement are discussed. (author)

  1. 3D prostate TRUS segmentation using globally optimized volume-preserving prior.

    Science.gov (United States)

    Qiu, Wu; Rajchl, Martin; Guo, Fumin; Sun, Yue; Ukwatta, Eranga; Fenster, Aaron; Yuan, Jing

    2014-01-01

    An efficient and accurate segmentation of 3D transrectal ultrasound (TRUS) images plays an important role in the planning and treatment of the practical 3D TRUS guided prostate biopsy. However, a meaningful segmentation of 3D TRUS images tends to suffer from US speckles, shadowing and missing edges etc, which make it a challenging task to delineate the correct prostate boundaries. In this paper, we propose a novel convex optimization based approach to extracting the prostate surface from the given 3D TRUS image, while preserving a new global volume-size prior. We, especially, study the proposed combinatorial optimization problem by convex relaxation and introduce its dual continuous max-flow formulation with the new bounded flow conservation constraint, which results in an efficient numerical solver implemented on GPUs. Experimental results using 12 patient 3D TRUS images show that the proposed approach while preserving the volume-size prior yielded a mean DSC of 89.5% +/- 2.4%, a MAD of 1.4 +/- 0.6 mm, a MAXD of 5.2 +/- 3.2 mm, and a VD of 7.5% +/- 6.2% in - 1 minute, deomonstrating the advantages of both accuracy and efficiency. In addition, the low standard deviation of the segmentation accuracy shows a good reliability of the proposed approach.

  2. Global and Regional 3D Tomography for Improved Seismic Event Location and Uncertainty in Explosion Monitoring

    Science.gov (United States)

    Downey, N.; Begnaud, M. L.; Hipp, J. R.; Ballard, S.; Young, C. S.; Encarnacao, A. V.

    2017-12-01

    The SALSA3D global 3D velocity model of the Earth was developed to improve the accuracy and precision of seismic travel time predictions for a wide suite of regional and teleseismic phases. Recently, the global SALSA3D model was updated to include additional body wave phases including mantle phases, core phases, reflections off the core-mantle boundary and underside reflections off the surface of the Earth. We show that this update improves travel time predictions and leads directly to significant improvements in the accuracy and precision of seismic event locations as compared to locations computed using standard 1D velocity models like ak135, or 2½D models like RSTT. A key feature of our inversions is that path-specific model uncertainty of travel time predictions are calculated using the full 3D model covariance matrix computed during tomography, which results in more realistic uncertainty ellipses that directly reflect tomographic data coverage. Application of this method can also be done at a regional scale: we present a velocity model with uncertainty obtained using data obtained from the University of Utah Seismograph Stations. These results show a reduction in travel-time residuals for re-located events compared with those obtained using previously published models.

  3. A 3-D Global History from a Glober Identity in a Noncentric and Holistic Perspective

    Institute of Scientific and Technical Information of China (English)

    Zhang Weiwei

    2014-01-01

    In modern times,global and world history has been understood,written and taught from either a national perspective or a regional/cultural/ideological one in the light of centrism such as West/Eurocentrism ever since it was created.The author argues,in a noncentric and holistic perspective,that nationalized global or world histories are nothing but distorting mirrors full of pride and prejudice.It is argued that both objective global history and subjective global history are contingent resultants in a certain special and temporal context.In the early 21st century,the author heralds a globalization of global history and "Global Historians of All Countries Unite!" He also suggests that it is necessary for a global historian to develop a glober identity beyond her/his national identity and that a reasonable and intelligible global history which is closer to the objective global history should be a 3-D global history of the glober,by the glober,for the glober.

  4. The 3-D global spatial data model foundation of the spatial data infrastructure

    CERN Document Server

    Burkholder, Earl F

    2008-01-01

    Traditional methods for handling spatial data are encumbered by the assumption of separate origins for horizontal and vertical measurements. Modern measurement systems operate in a 3-D spatial environment. The 3-D Global Spatial Data Model: Foundation of the Spatial Data Infrastructure offers a new model for handling digital spatial data, the global spatial data model or GSDM. The GSDM preserves the integrity of three-dimensional spatial data while also providing additional benefits such as simpler equations, worldwide standardization, and the ability to track spatial data accuracy with greater specificity and convenience. This groundbreaking spatial model incorporates both a functional model and a stochastic model to connect the physical world to the ECEF rectangular system. Combining horizontal and vertical data into a single, three-dimensional database, this authoritative monograph provides a logical development of theoretical concepts and practical tools that can be used to handle spatial data mo...

  5. Global analyses of historical masonry buildings: Equivalent frame vs. 3D solid models

    Science.gov (United States)

    Clementi, Francesco; Mezzapelle, Pardo Antonio; Cocchi, Gianmichele; Lenci, Stefano

    2017-07-01

    The paper analyses the seismic vulnerability of two different masonry buildings. It provides both an advanced 3D modelling with solid elements and an equivalent frame modelling. The global structural behaviour and the dynamic properties of the compound have been evaluated using the Finite Element Modelling (FEM) technique, where the nonlinear behaviour of masonry has been taken into account by proper constitutive assumptions. A sensitivity analysis is done to evaluate the effect of the choice of the structural models.

  6. Three-dimensional (3D) printed endovascular simulation models: a feasibility study.

    Science.gov (United States)

    Mafeld, Sebastian; Nesbitt, Craig; McCaslin, James; Bagnall, Alan; Davey, Philip; Bose, Pentop; Williams, Rob

    2017-02-01

    Three-dimensional (3D) printing is a manufacturing process in which an object is created by specialist printers designed to print in additive layers to create a 3D object. Whilst there are initial promising medical applications of 3D printing, a lack of evidence to support its use remains a barrier for larger scale adoption into clinical practice. Endovascular virtual reality (VR) simulation plays an important role in the safe training of future endovascular practitioners, but existing VR models have disadvantages including cost and accessibility which could be addressed with 3D printing. This study sought to evaluate the feasibility of 3D printing an anatomically accurate human aorta for the purposes of endovascular training. A 3D printed model was successfully designed and printed and used for endovascular simulation. The stages of development and practical applications are described. Feedback from 96 physicians who answered a series of questions using a 5 point Likert scale is presented. Initial data supports the value of 3D printed endovascular models although further educational validation is required.

  7. Global solution to the 3D inhomogeneous nematic liquid crystal flows with variable density

    Science.gov (United States)

    Hu, Xianpeng; Liu, Qiao

    2018-04-01

    In this paper, we investigate the global existence and uniqueness of solution to the 3D inhomogeneous incompressible nematic liquid crystal flows with variable density in the framework of Besov spaces. It is proved that there exists a global and unique solution to the nematic liquid crystal flows if the initial data (ρ0 - 1 ,u0 ,n0 -e3) ∈ M (B˙p,1 3/p - 1 (R3)) × B˙p,1 3/p - 1 (R3) × B˙p,1 3/p (R3) with 1 ≤ p < 6, and satisfies

  8. DEVELOPMENT OF A VIRTUAL 3D-SIMULATOR OF THE FEED PELLETING TECHNOLOGICAL PROCESS

    Directory of Open Access Journals (Sweden)

    N. Shcherbakov

    2017-08-01

    Full Text Available The process of developing a virtual 3D simulator of the process of granulation of mixed fodders is considered. The consequences of errors in the operation of press granulator operators are considered. The difficulties associated with the training of high-tech and expensive equipment operators are described. The necessity and described difficulties of acquiring practical skills of working with such equipment at the training stage are substantiated. It is argued the need to introduce computer simulators in educational institutions in order to improve the quality of the acquired knowledge, form a complex decision-making skill for future operators of technological processes. The results of a survey on improving the efficiency of management of technological processes after the introduction of simulators at enterprises are considered. The data of the simulator market and its forecasts for 2017 by regions and types of the interface used are presented. The conclusion is drawn about the growing popularity of simulators based on the 3D interface. The advantage of using the 3D interface with respect to the 2D interface is substantiated. The types of immersion in the learning environment in various simulator interfaces are considered. The vulnerabilities of the 3D simulator are noted. The goal is to develop a 3D simulator for a press granulator operator. A solution of a set of tasks is proposed to achieve this goal. The plan for creating a simulator was developed. A detailed consideration of the development stages of the simulator is given. The possibilities of using the simulator being developed are considered. The possibility of developing a simulator of emergency situations is described. The relevance of this development is justified.

  9. The Application of the Technology of 3D Satellite Cloud Imaging in Virtual Reality Simulation

    Directory of Open Access Journals (Sweden)

    Xiao-fang Xie

    2007-05-01

    Full Text Available Using satellite cloud images to simulate clouds is one of the new visual simulation technologies in Virtual Reality (VR. Taking the original data of satellite cloud images as the source, this paper depicts specifically the technology of 3D satellite cloud imaging through the transforming of coordinates and projection, creating a DEM (Digital Elevation Model of cloud imaging and 3D simulation. A Mercator projection was introduced to create a cloud image DEM, while solutions for geodetic problems were introduced to calculate distances, and the outer-trajectory science of rockets was introduced to obtain the elevation of clouds. For demonstration, we report on a computer program to simulate the 3D satellite cloud images.

  10. 3D Simulation of External Flooding Events for the RISMC Pathway

    International Nuclear Information System (INIS)

    Prescott, Steven; Mandelli, Diego; Sampath, Ramprasad; Smith, Curtis; Lin, Linyu

    2015-01-01

    Incorporating 3D simulations as part of the Risk-Informed Safety Margins Characterization (RISMIC) Toolkit allows analysts to obtain a more complete picture of complex system behavior for events including external plant hazards. External events such as flooding have become more important recently – however these can be analyzed with existing and validated simulated physics toolkits. In this report, we describe these approaches specific to flooding-based analysis using an approach called Smoothed Particle Hydrodynamics. The theory, validation, and example applications of the 3D flooding simulation are described. Integrating these 3D simulation methods into computational risk analysis provides a spatial/visual aspect to the design, improves the realism of results, and can prove visual understanding to validate the analysis of flooding.

  11. Monte Carlo simulation of the response of a pixellated 3D photo-detector in silicon

    CERN Document Server

    Dubaric, E; Froejdh, C; Norlin, B

    2002-01-01

    The charge transport and X-ray photon absorption in three-dimensional (3D) X-ray pixel detectors have been studied using numerical simulations. The charge transport has been modelled using the drift-diffusion simulator MEDICI, while photon absorption has been studied using MCNP. The response of the entire pixel detector system in terms of charge sharing, line spread function and modulation transfer function, has been simulated using a system level Monte Carlo simulation approach. A major part of the study is devoted to the effect of charge sharing on the energy resolution in 3D-pixel detectors. The 3D configuration was found to suppress charge sharing much better than conventional planar detectors.

  12. 3D Simulation of External Flooding Events for the RISMC Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Prescott, Steven [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mandelli, Diego [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sampath, Ramprasad [Idaho National Lab. (INL), Idaho Falls, ID (United States); Smith, Curtis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lin, Linyu [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    Incorporating 3D simulations as part of the Risk-Informed Safety Margins Characterization (RISMIC) Toolkit allows analysts to obtain a more complete picture of complex system behavior for events including external plant hazards. External events such as flooding have become more important recently – however these can be analyzed with existing and validated simulated physics toolkits. In this report, we describe these approaches specific to flooding-based analysis using an approach called Smoothed Particle Hydrodynamics. The theory, validation, and example applications of the 3D flooding simulation are described. Integrating these 3D simulation methods into computational risk analysis provides a spatial/visual aspect to the design, improves the realism of results, and can prove visual understanding to validate the analysis of flooding.

  13. Prototype Development Capabilities of 3D Spatial Interactions and Failures During Scenario Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Steven Prescott; Ramprasad Sampath; Curtis Smith; Tony Koonce

    2014-09-01

    Computers have been used for 3D modeling and simulation, but only recently have computational resources been able to give realistic results in a reasonable time frame for large complex models. This report addressed the methods, techniques, and resources used to develop a prototype for using 3D modeling and simulation engine to improve risk analysis and evaluate reactor structures and components for a given scenario. The simulations done for this evaluation were focused on external events, specifically tsunami floods, for a hypothetical nuclear power facility on a coastline.

  14. 3D skin surface reconstruction from a single image by merging global curvature and local texture using the guided filtering for 3D haptic palpation.

    Science.gov (United States)

    Lee, K; Kim, M; Kim, K

    2018-05-11

    Skin surface evaluation has been studied using various imaging techniques. However, all these studies had limited impact because they were performed using visual exam only. To improve on this scenario with haptic feedback, we propose 3D reconstruction of the skin surface using a single image. Unlike extant 3D skin surface reconstruction algorithms, we utilize the local texture and global curvature regions, combining the results for reconstruction. The first entails the reconstruction of global curvature, achieved by bilateral filtering that removes noise on the surface while maintaining the edge (ie, furrow) to obtain the overall curvature. The second entails the reconstruction of local texture, representing the fine wrinkles of the skin, using an advanced form of bilateral filtering. The final image is then composed by merging the two reconstructed images. We tested the curvature reconstruction part by comparing the resulting curvatures with measured values from real phantom objects while local texture reconstruction was verified by measuring skin surface roughness. Then, we showed the reconstructed result of our proposed algorithm via the reconstruction of various real skin surfaces. The experimental results demonstrate that our approach is a promising technology to reconstruct an accurate skin surface with a single skin image. We proposed 3D skin surface reconstruction using only a single camera. We highlighted the utility of global curvature, which has not been considered important in the past. Thus, we proposed a new method for 3D reconstruction that can be used for 3D haptic palpation, dividing the concepts of local and global regions. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. External force back-projective composition and globally deformable optimization for 3-D coronary artery reconstruction

    International Nuclear Information System (INIS)

    Yang, Jian; Cong, Weijian; Fan, Jingfan; Liu, Yue; Wang, Yongtian; Chen, Yang

    2014-01-01

    The clinical value of the 3D reconstruction of a coronary artery is important for the diagnosis and intervention of cardiovascular diseases. This work proposes a method based on a deformable model for reconstructing coronary arteries from two monoplane angiographic images acquired from different angles. First, an external force back-projective composition model is developed to determine the external force, for which the force distributions in different views are back-projected to the 3D space and composited in the same coordinate system based on the perspective projection principle of x-ray imaging. The elasticity and bending forces are composited as an internal force to maintain the smoothness of the deformable curve. Second, the deformable curve evolves rapidly toward the true vascular centerlines in 3D space and angiographic images under the combination of internal and external forces. Third, densely matched correspondence among vessel centerlines is constructed using a curve alignment method. The bundle adjustment method is then utilized for the global optimization of the projection parameters and the 3D structures. The proposed method is validated on phantom data and routine angiographic images with consideration for space and re-projection image errors. Experimental results demonstrate the effectiveness and robustness of the proposed method for the reconstruction of coronary arteries from two monoplane angiographic images. The proposed method can achieve a mean space error of 0.564 mm and a mean re-projection error of 0.349 mm. (paper)

  16. Statistical Analysis of Detailed 3-D CFD LES Simulations with Regard to CCV Modeling

    Directory of Open Access Journals (Sweden)

    Vítek Oldřich

    2016-06-01

    Full Text Available The paper deals with statistical analysis of large amount of detailed 3-D CFD data in terms of cycle-to-cycle variations (CCVs. These data were obtained by means of LES calculations of many consecutive cycles. Due to non-linear nature of Navier-Stokes equation set, there is a relatively significant CCV. Hence, every cycle is slightly different – this leads to requirement to perform statistical analysis based on ensemble averaging procedure which enables better understanding of CCV in ICE including its quantification. The data obtained from the averaging procedure provides results on different space resolution levels. The procedure is applied locally, i.e., in every cell of the mesh. Hence there is detailed CCV information on local level – such information can be compared with RANS simulations. Next, volume/mass averaging provides information at specific locations – e.g., gap between electrodes of a spark plug. Finally, volume/mass averaging of the whole combustion chamber leads to global information which can be compared with experimental data or results of system simulation tools (which are based on 0-D/1-D approach.

  17. An efficient global energy optimization approach for robust 3D plane segmentation of point clouds

    Science.gov (United States)

    Dong, Zhen; Yang, Bisheng; Hu, Pingbo; Scherer, Sebastian

    2018-03-01

    Automatic 3D plane segmentation is necessary for many applications including point cloud registration, building information model (BIM) reconstruction, simultaneous localization and mapping (SLAM), and point cloud compression. However, most of the existing 3D plane segmentation methods still suffer from low precision and recall, and inaccurate and incomplete boundaries, especially for low-quality point clouds collected by RGB-D sensors. To overcome these challenges, this paper formulates the plane segmentation problem as a global energy optimization because it is robust to high levels of noise and clutter. First, the proposed method divides the raw point cloud into multiscale supervoxels, and considers planar supervoxels and individual points corresponding to nonplanar supervoxels as basic units. Then, an efficient hybrid region growing algorithm is utilized to generate initial plane set by incrementally merging adjacent basic units with similar features. Next, the initial plane set is further enriched and refined in a mutually reinforcing manner under the framework of global energy optimization. Finally, the performances of the proposed method are evaluated with respect to six metrics (i.e., plane precision, plane recall, under-segmentation rate, over-segmentation rate, boundary precision, and boundary recall) on two benchmark datasets. Comprehensive experiments demonstrate that the proposed method obtained good performances both in high-quality TLS point clouds (i.e., http://SEMANTIC3D.NET)

  18. Cerebral Aneurysm Clipping Surgery Simulation Using Patient-Specific 3D Printing and Silicone Casting.

    Science.gov (United States)

    Ryan, Justin R; Almefty, Kaith K; Nakaji, Peter; Frakes, David H

    2016-04-01

    Neurosurgery simulator development is growing as practitioners recognize the need for improved instructional and rehearsal platforms to improve procedural skills and patient care. In addition, changes in practice patterns have decreased the volume of specific cases, such as aneurysm clippings, which reduces the opportunity for operating room experience. The authors developed a hands-on, dimensionally accurate model for aneurysm clipping using patient-derived anatomic data and three-dimensional (3D) printing. Design of the model focused on reproducibility as well as adaptability to new patient geometry. A modular, reproducible, and patient-derived medical simulacrum was developed for medical learners to practice aneurysmal clipping procedures. Various forms of 3D printing were used to develop a geometrically accurate cranium and vascular tree featuring 9 patient-derived aneurysms. 3D printing in conjunction with elastomeric casting was leveraged to achieve a patient-derived brain model with tactile properties not yet available from commercial 3D printing technology. An educational pilot study was performed to gauge simulation efficacy. Through the novel manufacturing process, a patient-derived simulacrum was developed for neurovascular surgical simulation. A follow-up qualitative study suggests potential to enhance current educational programs; assessments support the efficacy of the simulacrum. The proposed aneurysm clipping simulator has the potential to improve learning experiences in surgical environment. 3D printing and elastomeric casting can produce patient-derived models for a dynamic learning environment that add value to surgical training and preparation. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Calculation of residual stresses by means of a 3D numerical weld simulation

    International Nuclear Information System (INIS)

    Nicak, Tomas; Huemmer, Matthias

    2008-01-01

    The numerical weld simulation has developed very fast in recent years. The problem complexity has increased from simple 2D models to full 3D models, which can describe the entire welding process more realistically. As recent research projects indicate, a quantitative assessment of the residual stresses by means of a 3D analysis is possible. The structure integrity can be assessed based on the weld simulation results superimposed with the operating load. Moreover, to support the qualification of welded components parametric studies for optimization of the residual stress distribution in the weld region can be performed. In this paper a full 3D numerical weld simulation for a man-hole drainage nozzle in a steam generator will be presented. The residual stresses are calculated by means of an uncoupled transient thermal and mechanical FE analysis. The paper will present a robust procedure allowing reasonable predictions of the residual stresses for complex structures in industrial practice. (authors)

  20. 3D city models as a basis for heat demand simulations; 3D-Stadtmodelle als Grundlage fuer Waermebedarfssimulationen

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, Claudia; Coors, Volker; Eicker, Ursula [Hochschule fuer Technik (HFT), Stuttgart (Germany)

    2012-07-01

    The biggest potential for heat consumption reduction and CO2 emission reduction in Germany is in older buildings. By applying innovative modernization concepts, primary energy consumption could be reduced by 80 percent. Planning of modernisation and energy concepts requires data on the current status. HFT Stuttgart developed a promising method for assessing heat consumption according to DIN 18599 of urban districts on the basis of 3D models of buildings (CityGML). The method is presented and explained here.

  1. 3D-printed pediatric endoscopic ear surgery simulator for surgical training.

    Science.gov (United States)

    Barber, Samuel R; Kozin, Elliott D; Dedmon, Matthew; Lin, Brian M; Lee, Kyuwon; Sinha, Sumi; Black, Nicole; Remenschneider, Aaron K; Lee, Daniel J

    2016-11-01

    Surgical simulators are designed to improve operative skills and patient safety. Transcanal Endoscopic Ear Surgery (TEES) is a relatively new surgical approach with a slow learning curve due to one-handed dissection. A reusable and customizable 3-dimensional (3D)-printed endoscopic ear surgery simulator may facilitate the development of surgical skills with high fidelity and low cost. Herein, we aim to design, fabricate, and test a low-cost and reusable 3D-printed TEES simulator. The TEES simulator was designed in computer-aided design (CAD) software using anatomic measurements taken from anthropometric studies. Cross sections from external auditory canal samples were traced as vectors and serially combined into a mesh construct. A modified tympanic cavity with a modular testing platform for simulator tasks was incorporated. Components were fabricated using calcium sulfate hemihydrate powder and multiple colored infiltrants via a commercial inkjet 3D-printing service. All components of a left-sided ear were printed to scale. Six right-handed trainees completed three trials each. Mean trial time (n = 3) ranged from 23.03 to 62.77 s using the dominant hand for all dissection. Statistically significant differences between first and last completion time with the dominant hand (p 3D-printed simulator is feasible for TEES simulation. Otolaryngology training programs with access to a 3D printer may readily fabricate a TEES simulator, resulting in inexpensive yet high-fidelity surgical simulation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  2. Pre-operative simulation of pediatric mastoid surgery with 3D-printed temporal bone models.

    Science.gov (United States)

    Rose, Austin S; Webster, Caroline E; Harrysson, Ola L A; Formeister, Eric J; Rawal, Rounak B; Iseli, Claire E

    2015-05-01

    As the process of additive manufacturing, or three-dimensional (3D) printing, has become more practical and affordable, a number of applications for the technology in the field of pediatric otolaryngology have been considered. One area of promise is temporal bone surgical simulation. Having previously developed a model for temporal bone surgical training using 3D printing, we sought to produce a patient-specific model for pre-operative simulation in pediatric otologic surgery. Our hypothesis was that the creation and pre-operative dissection of such a model was possible, and would demonstrate potential benefits in cases of abnormal temporal bone anatomy. In the case presented, an 11-year-old boy underwent a planned canal-wall-down (CWD) tympano-mastoidectomy for recurrent cholesteatoma preceded by a pre-operative surgical simulation using 3D-printed models of the temporal bone. The models were based on the child's pre-operative clinical CT scan and printed using multiple materials to simulate both bone and soft tissue structures. To help confirm the models as accurate representations of the child's anatomy, distances between various anatomic landmarks were measured and compared to the temporal bone CT scan and the 3D model. The simulation allowed the surgical team to appreciate the child's unusual temporal bone anatomy as well as any challenges that might arise in the safety of the temporal bone laboratory, prior to actual surgery in the operating room (OR). There was minimal variability, in terms of absolute distance (mm) and relative distance (%), in measurements between anatomic landmarks obtained from the patient intra-operatively, the pre-operative CT scan and the 3D-printed models. Accurate 3D temporal bone models can be rapidly produced based on clinical CT scans for pre-operative simulation of specific challenging otologic cases in children, potentially reducing medical errors and improving patient safety. Copyright © 2015 Elsevier Ireland Ltd. All rights

  3. Simulation Of Seawater Intrusion With 2D And 3D Models: Nauru Island Case Study

    Science.gov (United States)

    Ghassemi, F.; Jakeman, A. J.; Jacobson, G.; Howard, K. W. F.

    1996-03-01

    With the advent of large computing capacities during the past few decades, sophisticated models have been developed for the simulation of seawater intrusion in coastal and island aquifers. Currently, several models are commercially available for the simulation of this problem. This paper describes the mathematical basis and application of the SUTRA and HST3D models to simulate seawater intrusion in Nauru Island, in the central Pacific Ocean. A comparison of the performance and limitations of these two models in simulating a real problem indicates that three-dimensional simulation of seawater intrusion with the HST3D model has the major advantage of being able to specify natural boundary conditions as well as pumping stresses. However, HST3D requires a small grid size and short time steps in order to maintain numerical stability and accuracy. These requirements lead to solution of a large set of linear equations that requires the availability of powerful computing facilities in terms of memory and computing speed. Combined results of the two simulation models indicate a safe pumping rate of 400 m3/d for the aquifer on Nauru Island, where additional fresh water is presently needed for the rehabilitation of mined-out land.

  4. Mixed reality orthognathic surgical simulation by entity model manipulation and 3D-image display

    Science.gov (United States)

    Shimonagayoshi, Tatsunari; Aoki, Yoshimitsu; Fushima, Kenji; Kobayashi, Masaru

    2005-12-01

    In orthognathic surgery, the framing of 3D-surgical planning that considers the balance between the front and back positions and the symmetry of the jawbone, as well as the dental occlusion of teeth, is essential. In this study, a support system for orthodontic surgery to visualize the changes in the mandible and the occlusal condition and to determine the optimum position in mandibular osteotomy has been developed. By integrating the operating portion of a tooth model that is to determine the optimum occlusal position by manipulating the entity tooth model and the 3D-CT skeletal images (3D image display portion) that are simultaneously displayed in real-time, the determination of the mandibular position and posture in which the improvement of skeletal morphology and occlusal condition is considered, is possible. The realistic operation of the entity model and the virtual 3D image display enabled the construction of a surgical simulation system that involves augmented reality.

  5. specsim: A Fortran-77 program for conditional spectral simulation in 3D

    Science.gov (United States)

    Yao, Tingting

    1998-12-01

    A Fortran 77 program, specsim, is presented for conditional spectral simulation in 3D domains. The traditional Fourier integral method allows generating random fields with a given covariance spectrum. Conditioning to local data is achieved by an iterative identification of the conditional phase information. A flowchart of the program is given to illustrate the implementation procedures of the program. A 3D case study is presented to demonstrate application of the program. A comparison with the traditional sequential Gaussian simulation algorithm emphasizes the advantages and drawbacks of the proposed algorithm.

  6. Simulation of Missing Pellet Surface thermal behavior with 3D dynamic gap element

    International Nuclear Information System (INIS)

    Kim, Hyo Chan; Yang, Yong Sik; Koo, Yang Hyun; Kang, Chang Hak; Lee Sung Uk; Yang, Dong Yol

    2014-01-01

    Most of the fuel performance codes that are able to simulate a multidimensional analysis are used to calculate the radial temperature distribution and perform a multidimensional mechanical analysis based on a one-dimensional (1D) temperature result. The FRAPCON-FRAPTRAN code system incorporates a 1D thermal module and two-dimensional (2D) mechanical module when FEM option is activated. In this method, the multidimensional gap conductance model is not required because one-dimensional thermal analysis is carried out. On the other hand, a gap conductance model for a multi-dimension should be developed in the code to perform a multidimensional thermal analysis. ALCYONE developed by CEA introduces an equivalent heat convection coefficient that represents the multidimensional gap conductance. However, the code does not employ dynamic gap conductance which is a function of gap thickness and gap characteristics in direct. The BISON code, which has been developed by INL (Idaho National Laboratory), employed a thermo-mechanical contact method that is specifically designed for tightly-coupled implicit solutions that employ Jacobian-free solution methods. Owing to tightly-coupled implicit solutions, the BISON code solves gap conductance and gap thickness simultaneously with given boundary conditions. In this paper, 3D dynamic gap element has been proposed to resolve convergence issue and nonlinear characteristic of multidimensional gap conductance. To evaluate 3D dynamic gap element module, 3D thermomechanical module using FORTRAN77 has been implemented incorporating 3D dynamic gap element. To demonstrate effect of 3D dynamic gap element, thermal behavior of missing pellet surface (MPS) has been simulated by the developed module. LWR fuel performance codes should incorporate thermo-mechanical loop to solve gap conductance problem, iteratively. However, gap conductance in multidimensional model is difficult issue owing to its nonlinearity and convergence characteristics. In

  7. Flow MRI simulation in complex 3D geometries: Application to the cerebral venous network.

    Science.gov (United States)

    Fortin, Alexandre; Salmon, Stéphanie; Baruthio, Joseph; Delbany, Maya; Durand, Emmanuel

    2018-02-05

    Develop and evaluate a complete tool to include 3D fluid flows in MRI simulation, leveraging from existing software. Simulation of MR spin flow motion is of high interest in the study of flow artifacts and angiography. However, at present, only a few simulators include this option and most are restricted to static tissue imaging. An extension of JEMRIS, one of the most advanced high performance open-source simulation platforms to date, was developed. The implementation of a Lagrangian description of the flow allows simulating any MR experiment, including both static tissues and complex flow data from computational fluid dynamics. Simulations of simple flow models are compared with real experiments on a physical flow phantom. A realistic simulation of 3D flow MRI on the cerebral venous network is also carried out. Simulations and real experiments are in good agreement. The generality of the framework is illustrated in 2D and 3D with some common flow artifacts (misregistration and inflow enhancement) and with the three main angiographic techniques: phase contrast velocimetry (PC), time-of-flight, and contrast-enhanced imaging MRA. The framework provides a versatile and reusable tool for the simulation of any MRI experiment including physiological fluids and arbitrarily complex flow motion. © 2018 International Society for Magnetic Resonance in Medicine.

  8. Precipitation Processes Developed During ARM (1997), TOGA COARE (1992) GATE (1974), SCSMEX (1998), and KWAJEX (1999): Consistent 3D, Semi-3D and 3D Cloud Resolving Model Simulations

    Science.gov (United States)

    Tao, W.-K.; Hou, A.; Atlas, R.; Starr, D.; Sud, Y.

    2003-01-01

    Real clouds and cloud systems are inherently three-dimensional (3D). Because of the limitations in computer resources, however, most cloud-resolving models (CRMs) today are still two-dimensional (2D) have been used to study the response of clouds to large-scale forcing. IN these 3D simulators, the model domain was small, and the integration time was 6 hours. Only recently have 3D experiments been performed for multi-day periods for tropical clouds systems with large horizontal domains at the National Center of Atmospheric Research (NCAR) and at NASA Goddard Space Center. At Goddard, a 3D cumulus Ensemble (GCE) model was used to simulate periods during TOGA COARE, GATE, SCSMEX, ARM, and KWAJEX using a 512 by 512 km domain (with 2-km resolution). The result indicate that surface precipitation and latent heating profiles are very similar between the 2D and 3D GCE model simulation. The major objective of this paper are: (1) to assess the performance of the super-parametrization technique, (2) calculate and examine the surface energy (especially radiation) and water budget, and (3) identify the differences and similarities in the organization and entrainment rates of convection between simulated 2D and 3D cloud systems.

  9. Marine denitrification rates determined from a global 3-D inverse model

    Directory of Open Access Journals (Sweden)

    T. DeVries

    2013-04-01

    Full Text Available A major impediment to understanding long-term changes in the marine nitrogen (N cycle is the persistent uncertainty about the rates, distribution, and sensitivity of its largest fluxes in the modern ocean. We use a global ocean circulation model to obtain the first 3-D estimate of marine denitrification rates that is maximally consistent with available observations of nitrate deficits and the nitrogen isotopic ratio of oceanic nitrate. We find a global rate of marine denitrification in suboxic waters and sediments of 120–240 Tg N yr−1, which is lower than many other recent estimates. The difference stems from the ability to represent the 3-D spatial structure of suboxic zones, where denitrification rates of 50–77 Tg N yr−1 result in up to 50% depletion of nitrate. This depletion reduces the effect of local isotopic enrichment on the rest of the ocean, allowing the N isotope ratio of oceanic nitrate to be achieved with a sedimentary denitrification rate about 1.3–2.3 times that of suboxic zones. This balance of N losses between sediments and suboxic zones is shown to obey a simple relationship between isotope fractionation and the degree of nitrate consumption in the core of the suboxic zones. The global denitrification rates derived here suggest that the marine nitrogen budget is likely close to balanced.

  10. Estimation of Atmospheric Methane Surface Fluxes Using a Global 3-D Chemical Transport Model

    Science.gov (United States)

    Chen, Y.; Prinn, R.

    2003-12-01

    Accurate determination of atmospheric methane surface fluxes is an important and challenging problem in global biogeochemical cycles. We use inverse modeling to estimate annual, seasonal, and interannual CH4 fluxes between 1996 and 2001. The fluxes include 7 time-varying seasonal (3 wetland, rice, and 3 biomass burning) and 3 steady aseasonal (animals/waste, coal, and gas) global processes. To simulate atmospheric methane, we use the 3-D chemical transport model MATCH driven by NCEP reanalyzed observed winds at a resolution of T42 ( ˜2.8° x 2.8° ) in the horizontal and 28 levels (1000 - 3 mb) in the vertical. By combining existing datasets of individual processes, we construct a reference emissions field that represents our prior guess of the total CH4 surface flux. For the methane sink, we use a prescribed, annually-repeating OH field scaled to fit methyl chloroform observations. MATCH is used to produce both the reference run from the reference emissions, and the time-dependent sensitivities that relate individual emission processes to observations. The observational data include CH4 time-series from ˜15 high-frequency (in-situ) and ˜50 low-frequency (flask) observing sites. Most of the high-frequency data, at a time resolution of 40-60 minutes, have not previously been used in global scale inversions. In the inversion, the high-frequency data generally have greater weight than the weekly flask data because they better define the observational monthly means. The Kalman Filter is used as the optimal inversion technique to solve for emissions between 1996-2001. At each step in the inversion, new monthly observations are utilized and new emissions estimates are produced. The optimized emissions represent deviations from the reference emissions that lead to a better fit to the observations. The seasonal processes are optimized for each month, and contain the methane seasonality and interannual variability. The aseasonal processes, which are less variable, are

  11. A Novel Temporal Bone Simulation Model Using 3D Printing Techniques.

    Science.gov (United States)

    Mowry, Sarah E; Jammal, Hachem; Myer, Charles; Solares, Clementino Arturo; Weinberger, Paul

    2015-09-01

    An inexpensive temporal bone model for use in a temporal bone dissection laboratory setting can be made using a commercially available, consumer-grade 3D printer. Several models for a simulated temporal bone have been described but use commercial-grade printers and materials to produce these models. The goal of this project was to produce a plastic simulated temporal bone on an inexpensive 3D printer that recreates the visual and haptic experience associated with drilling a human temporal bone. Images from a high-resolution CT of a normal temporal bone were converted into stereolithography files via commercially available software, with image conversion and print settings adjusted to achieve optimal print quality. The temporal bone model was printed using acrylonitrile butadiene styrene (ABS) plastic filament on a MakerBot 2x 3D printer. Simulated temporal bones were drilled by seven expert temporal bone surgeons, assessing the fidelity of the model as compared with a human cadaveric temporal bone. Using a four-point scale, the simulated bones were assessed for haptic experience and recreation of the temporal bone anatomy. The created model was felt to be an accurate representation of a human temporal bone. All raters felt strongly this would be a good training model for junior residents or to simulate difficult surgical anatomy. Material cost for each model was $1.92. A realistic, inexpensive, and easily reproducible temporal bone model can be created on a consumer-grade desktop 3D printer.

  12. Existence and uniqueness of global solutions for the modified anisotropic 3D Navier−Stokes equations

    KAUST Repository

    Bessaih, Hakima

    2016-01-27

    We study a modified three-dimensional incompressible anisotropic Navier−Stokes equations. The modification consists in the addition of a power term to the nonlinear convective one. This modification appears naturally in porous media when a fluid obeys the Darcy−Forchheimer law instead of the classical Darcy law. We prove global in time existence and uniqueness of solutions without assuming the smallness condition on the initial data. This improves the result obtained for the classical 3D incompressible anisotropic Navier−Stokes equations.

  13. Using 3D Printing (Additive Manufacturing) to Produce Low-Cost Simulation Models for Medical Training.

    Science.gov (United States)

    Lichtenberger, John P; Tatum, Peter S; Gada, Satyen; Wyn, Mark; Ho, Vincent B; Liacouras, Peter

    2018-03-01

    This work describes customized, task-specific simulation models derived from 3D printing in clinical settings and medical professional training programs. Simulation models/task trainers have an array of purposes and desired achievements for the trainee, defining that these are the first step in the production process. After this purpose is defined, computer-aided design and 3D printing (additive manufacturing) are used to create a customized anatomical model. Simulation models then undergo initial in-house testing by medical specialists followed by a larger scale beta testing. Feedback is acquired, via surveys, to validate effectiveness and to guide or determine if any future modifications and/or improvements are necessary. Numerous custom simulation models have been successfully completed with resulting task trainers designed for procedures, including removal of ocular foreign bodies, ultrasound-guided joint injections, nerve block injections, and various suturing and reconstruction procedures. These task trainers have been frequently utilized in the delivery of simulation-based training with increasing demand. 3D printing has been integral to the production of limited-quantity, low-cost simulation models across a variety of medical specialties. In general, production cost is a small fraction of a commercial, generic simulation model, if available. These simulation and training models are customized to the educational need and serve an integral role in the education of our military health professionals.

  14. 3-D FDTD simulation of shear waves for evaluation of complex modulus imaging.

    Science.gov (United States)

    Orescanin, Marko; Wang, Yue; Insana, Michael

    2011-02-01

    The Navier equation describing shear wave propagation in 3-D viscoelastic media is solved numerically with a finite differences time domain (FDTD) method. Solutions are formed in terms of transverse scatterer velocity waves and then verified via comparison to measured wave fields in heterogeneous hydrogel phantoms. The numerical algorithm is used as a tool to study the effects on complex shear modulus estimation from wave propagation in heterogeneous viscoelastic media. We used an algebraic Helmholtz inversion (AHI) technique to solve for the complex shear modulus from simulated and experimental velocity data acquired in 2-D and 3-D. Although 3-D velocity estimates are required in general, there are object geometries for which 2-D inversions provide accurate estimations of the material properties. Through simulations and experiments, we explored artifacts generated in elastic and dynamic-viscous shear modulus images related to the shear wavelength and average viscosity.

  15. "Just-In-Time" Simulation Training Using 3-D Printed Cardiac Models After Congenital Cardiac Surgery.

    Science.gov (United States)

    Olivieri, Laura J; Su, Lillian; Hynes, Conor F; Krieger, Axel; Alfares, Fahad A; Ramakrishnan, Karthik; Zurakowski, David; Marshall, M Blair; Kim, Peter C W; Jonas, Richard A; Nath, Dilip S

    2016-03-01

    High-fidelity simulation using patient-specific three-dimensional (3D) models may be effective in facilitating pediatric cardiac intensive care unit (PCICU) provider training for clinical management of congenital cardiac surgery patients. The 3D-printed heart models were rendered from preoperative cross-sectional cardiac imaging for 10 patients undergoing congenital cardiac surgery. Immediately following surgical repair, a congenital cardiac surgeon and an intensive care physician conducted a simulation training session regarding postoperative care utilizing the patient-specific 3D model for the PCICU team. After the simulation, Likert-type 0 to 10 scale questionnaire assessed participant perception of impact of the training session. Seventy clinicians participated in training sessions, including 22 physicians, 38 nurses, and 10 ancillary care providers. Average response to whether 3D models were more helpful than standard hand off was 8.4 of 10. Questions regarding enhancement of understanding and clinical ability received average responses of 9.0 or greater, and 90% of participants scored 8 of 10 or higher. Nurses scored significantly higher than other clinicians on self-reported familiarity with the surgery (7.1 vs. 5.8; P = .04), clinical management ability (8.6 vs. 7.7; P = .02), and ability enhancement (9.5 vs. 8.7; P = .02). Compared to physicians, nurses and ancillary providers were more likely to consider 3D models more helpful than standard hand off (8.7 vs. 7.7; P = .05). Higher case complexity predicted greater enhancement of understanding of surgery (P = .04). The 3D heart models can be used to enhance congenital cardiac critical care via simulation training of multidisciplinary intensive care teams. Benefit may be dependent on provider type and case complexity. © The Author(s) 2016.

  16. Development of 3D dynamic gap element for simulation of asymmetric fuel behavior

    International Nuclear Information System (INIS)

    Kim, Hyochan; Yang, Yongsik; Koo, Yanghyun; Kang, Changhak; Lee, Sunguk; Yang, Dongyol

    2014-01-01

    The accurate modeling of heat transfer across the gap between fuel pellets and the protective cladding is essential to understanding the fuel performance, including cladding stress and behavior under irradiated conditions. To establish a heat transfer model through a gap in the fuel performance code, the gap conductance based on the Ross and Stoute model was employed in most previous works. In this model, the gap conductance that determines the temperature gradient within the gap is a function of gap thickness, which is dependent on mechanical behavior. Recently, many researchers have been developing fuel performance codes based on the finite element method (FE) to calculate the temperature, stress, and strain in 2D or 3D. The gap conductance model for FE can be a challenging issue in terms of convergence and nonlinearity because the elements that are positioned in a gap have a different gap conductance, and the boundary conditions of the gap vary at each iteration step. In this paper, the specified 3D dynamic gap element has been proposed and implemented to simulate asymmetric thermo-mechanical fuel behavior. A thermo-mechanical 3D finite element module incorporating a gap element has been implemented using FORTRAN77. To evaluate the proposed 3D gap element, the missing pellet surface (MPS), which results in an asymmetric heat transfer in the pellet and cladding, was simulated. As a result, the maximum temperature of a pellet for the MPS problem calculated with the specified 3D gap element is much higher than the temperature calculated with a uniform gap conductance model that a multidimensional fuel performance code employs. The results demonstrate that a 3D simulation is essential to evaluate the temperature and stress of the pellet and cladding for an asymmetric geometry simulation. (author)

  17. Collaborative Multi-Scale 3d City and Infrastructure Modeling and Simulation

    Science.gov (United States)

    Breunig, M.; Borrmann, A.; Rank, E.; Hinz, S.; Kolbe, T.; Schilcher, M.; Mundani, R.-P.; Jubierre, J. R.; Flurl, M.; Thomsen, A.; Donaubauer, A.; Ji, Y.; Urban, S.; Laun, S.; Vilgertshofer, S.; Willenborg, B.; Menninghaus, M.; Steuer, H.; Wursthorn, S.; Leitloff, J.; Al-Doori, M.; Mazroobsemnani, N.

    2017-09-01

    Computer-aided collaborative and multi-scale 3D planning are challenges for complex railway and subway track infrastructure projects in the built environment. Many legal, economic, environmental, and structural requirements have to be taken into account. The stringent use of 3D models in the different phases of the planning process facilitates communication and collaboration between the stake holders such as civil engineers, geological engineers, and decision makers. This paper presents concepts, developments, and experiences gained by an interdisciplinary research group coming from civil engineering informatics and geo-informatics banding together skills of both, the Building Information Modeling and the 3D GIS world. New approaches including the development of a collaborative platform and 3D multi-scale modelling are proposed for collaborative planning and simulation to improve the digital 3D planning of subway tracks and other infrastructures. Experiences during this research and lessons learned are presented as well as an outlook on future research focusing on Building Information Modeling and 3D GIS applications for cities of the future.

  18. COLLABORATIVE MULTI-SCALE 3D CITY AND INFRASTRUCTURE MODELING AND SIMULATION

    Directory of Open Access Journals (Sweden)

    M. Breunig

    2017-09-01

    Full Text Available Computer-aided collaborative and multi-scale 3D planning are challenges for complex railway and subway track infrastructure projects in the built environment. Many legal, economic, environmental, and structural requirements have to be taken into account. The stringent use of 3D models in the different phases of the planning process facilitates communication and collaboration between the stake holders such as civil engineers, geological engineers, and decision makers. This paper presents concepts, developments, and experiences gained by an interdisciplinary research group coming from civil engineering informatics and geo-informatics banding together skills of both, the Building Information Modeling and the 3D GIS world. New approaches including the development of a collaborative platform and 3D multi-scale modelling are proposed for collaborative planning and simulation to improve the digital 3D planning of subway tracks and other infrastructures. Experiences during this research and lessons learned are presented as well as an outlook on future research focusing on Building Information Modeling and 3D GIS applications for cities of the future.

  19. Vectorization and parallelization of a numerical scheme for 3D global atmospheric transport-chemistry problems

    NARCIS (Netherlands)

    E.J. Spee (Edwin); P.M. de Zeeuw (Paul); J.G. Verwer (Jan); J.G. Blom (Joke); W. Hundsdorfer (Willem)

    1996-01-01

    textabstractAtmospheric air quality modeling relies in part on numerical simulation. Required numerical simulations are often hampered by lack of computer capacity and computational speed. This problem is most severe in the field of global modeling where transport and exchange of trace constituents

  20. Renal Tumor Cryoablation Planning. The Efficiency of Simulation on Reconstructed 3D CT Scan

    Directory of Open Access Journals (Sweden)

    Ciprian Valerian LUCAN

    2010-12-01

    Full Text Available Introduction & Objective: Nephron-sparing surgical techniques risks are related to tumor relationships with adjacent anatomic structures. Complexity of the renal anatomy drives the interest to develop tools for 3D reconstruction and surgery simulation. The aim of the article was to assess the simulation on reconstructed 3D CT scan used for planning the cryoablation. Material & Method: A prospective randomized study was performed between Jan. 2007 and July 2009 on 27 patients who underwent retroperitoneoscopic T1a renal tumors cryoablation (RC. All patients were assessed preoperatively by CT scan, also used for 3D volume rendering. In the Gr.A, the patients underwent surgery planning by simulation on 3D CT scan. In the Gr.B., patients underwent standard RC. The two groups were compared in terms of surgical time, bleeding, postoperative drainage, analgesics requirement, hospital stay, time to socio-professional reintegration. Results: Fourteen patients underwent preoperative cryoablation planning (Gr.A and 13 patients underwent standard CR (Gr.B. All parameters analyzed were shorter in the Gr.A. On multivariate logistic regression, only shortens of the surgical time (138.79±5.51 min. in Gr.A. vs. 140.92±5.54 min in Gr.B. and bleeding (164.29±60.22 mL in Gr.A. vs. 215.38±100.80 mL in Gr.B. achieved statistical significance (p<0.05. The number of cryoneedles assessed by simulation had a 92.52% accuracy when compared with those effectively used. Conclusions: Simulation of the cryoablation using reconstructed 3D CT scan improves the surgical results. The application used for simulation was able to accurately assess the number of cryoneedles required for tumor ablation, their direction and approach.

  1. RapidArc treatment verification in 3D using polymer gel dosimetry and Monte Carlo simulation

    DEFF Research Database (Denmark)

    Ceberg, Sofie; Gagne, Isabel; Gustafsson, Helen

    2010-01-01

    The aim of this study was to verify the advanced inhomogeneous dose distribution produced by a volumetric arc therapy technique (RapidArc™) using 3D gel measurements and Monte Carlo (MC) simulations. The TPS (treatment planning system)-calculated dose distribution was compared with gel measurements...

  2. 3-D modeling and motion simulation of fuel rod-replacing equipment

    International Nuclear Information System (INIS)

    Ding Jie; Zhu Libing

    2010-01-01

    In this paper, the process of 3-D modeling and motion simulation of fuel rod-replacing equipment using SolidWorks is described, and the application of SolidWorks in manufacturing and design improvement is discussed. Complexity of the manufacturing is reduced and reliability of the design is improved. (authors)

  3. 3D and 4D Simulations for Landscape Reconstruction and Damage Scenarios: GIS Pilot Applications

    Science.gov (United States)

    Pesaresi, Cristano; Van Der Schee, Joop; Pavia, Davide

    2017-01-01

    The project "3D and 4D Simulations for Landscape Reconstruction and Damage Scenarios: GIS Pilot Applications" has been devised with the intention to deal with the demand for research, innovation and applicative methodology on the part of the international programme, requiring concrete results to increase the capacity to know, anticipate…

  4. Qualitative Assessment of a 3D Simulation Program: Faculty, Students, and Bio-Organic Reaction Animations

    Science.gov (United States)

    Günersel, Adalet B.; Fleming, Steven A.

    2013-01-01

    Research shows that computer-based simulations and animations are especially helpful in fields such as chemistry where concepts are abstract and cannot be directly observed. Bio-Organic Reaction Animations (BioORA) is a freely available 3D visualization software program developed to help students understand the chemistry of biomolecular events.…

  5. Simulating streamer discharges in 3D with the parallel adaptive Afivo framework

    NARCIS (Netherlands)

    H.J. Teunissen (Jannis); U. M. Ebert (Ute)

    2017-01-01

    htmlabstractWe present an open-source plasma fluid code for 2D, cylindrical and 3D simulations of streamer discharges, based on the Afivo framework that features adaptive mesh refinement, geometric multigrid methods for Poisson's equation, and OpenMP parallelism. We describe the numerical

  6. Impact of mesh and DEM resolutions in SEM simulation of 3D seismic response

    NARCIS (Netherlands)

    Khan, Saad; van der Meijde, M.; van der Werff, H.M.A.; Shafique, Muhammad

    2017-01-01

    This study shows that the resolution of a digital elevation model (DEM) and model mesh strongly influences 3D simulations of seismic response. Topographic heterogeneity scatters seismic waves and causes variation in seismic response (am-plification and deamplification of seismic amplitudes) at the

  7. An Object-Oriented Simulator for 3D Digital Breast Tomosynthesis Imaging System

    Directory of Open Access Journals (Sweden)

    Saeed Seyyedi

    2013-01-01

    Full Text Available Digital breast tomosynthesis (DBT is an innovative imaging modality that provides 3D reconstructed images of breast to detect the breast cancer. Projections obtained with an X-ray source moving in a limited angle interval are used to reconstruct 3D image of breast. Several reconstruction algorithms are available for DBT imaging. Filtered back projection algorithm has traditionally been used to reconstruct images from projections. Iterative reconstruction algorithms such as algebraic reconstruction technique (ART were later developed. Recently, compressed sensing based methods have been proposed in tomosynthesis imaging problem. We have developed an object-oriented simulator for 3D digital breast tomosynthesis (DBT imaging system using C++ programming language. The simulator is capable of implementing different iterative and compressed sensing based reconstruction methods on 3D digital tomosynthesis data sets and phantom models. A user friendly graphical user interface (GUI helps users to select and run the desired methods on the designed phantom models or real data sets. The simulator has been tested on a phantom study that simulates breast tomosynthesis imaging problem. Results obtained with various methods including algebraic reconstruction technique (ART and total variation regularized reconstruction techniques (ART+TV are presented. Reconstruction results of the methods are compared both visually and quantitatively by evaluating performances of the methods using mean structural similarity (MSSIM values.

  8. An object-oriented simulator for 3D digital breast tomosynthesis imaging system.

    Science.gov (United States)

    Seyyedi, Saeed; Cengiz, Kubra; Kamasak, Mustafa; Yildirim, Isa

    2013-01-01

    Digital breast tomosynthesis (DBT) is an innovative imaging modality that provides 3D reconstructed images of breast to detect the breast cancer. Projections obtained with an X-ray source moving in a limited angle interval are used to reconstruct 3D image of breast. Several reconstruction algorithms are available for DBT imaging. Filtered back projection algorithm has traditionally been used to reconstruct images from projections. Iterative reconstruction algorithms such as algebraic reconstruction technique (ART) were later developed. Recently, compressed sensing based methods have been proposed in tomosynthesis imaging problem. We have developed an object-oriented simulator for 3D digital breast tomosynthesis (DBT) imaging system using C++ programming language. The simulator is capable of implementing different iterative and compressed sensing based reconstruction methods on 3D digital tomosynthesis data sets and phantom models. A user friendly graphical user interface (GUI) helps users to select and run the desired methods on the designed phantom models or real data sets. The simulator has been tested on a phantom study that simulates breast tomosynthesis imaging problem. Results obtained with various methods including algebraic reconstruction technique (ART) and total variation regularized reconstruction techniques (ART+TV) are presented. Reconstruction results of the methods are compared both visually and quantitatively by evaluating performances of the methods using mean structural similarity (MSSIM) values.

  9. 3D printed mitral valve models: affordable simulation for robotic mitral valve repair.

    Science.gov (United States)

    Premyodhin, Ned; Mandair, Divneet; Ferng, Alice S; Leach, Timothy S; Palsma, Ryan P; Albanna, Mohammad Z; Khalpey, Zain I

    2018-01-01

    3D printed mitral valve (MV) models that capture the suture response of real tissue may be utilized as surgical training tools. Leveraging clinical imaging modalities, 3D computerized modelling and 3D printing technology to produce affordable models complements currently available virtual simulators and paves the way for patient- and pathology-specific preoperative rehearsal. We used polyvinyl alcohol, a dissolvable thermoplastic, to 3D print moulds that were casted with liquid platinum-cure silicone yielding flexible, low-cost MV models capable of simulating valvular tissue. Silicone-moulded MV models were fabricated for 2 morphologies: the normal MV and the P2 flail. The moulded valves were plication and suture tested in a laparoscopic trainer box with a da Vinci Si robotic surgical system. One cardiothoracic surgery fellow and 1 attending surgeon qualitatively evaluated the ability of the valves to recapitulate tissue feel through surveys utilizing the 5-point Likert-type scale to grade impressions of the valves. Valves produced with the moulding and casting method maintained anatomical dimensions within 3% of directly 3D printed acrylonitrile butadiene styrene controls for both morphologies. Likert-type scale mean scores corresponded with a realistic material response to sutures (5.0/5), tensile strength that is similar to real MV tissue (5.0/5) and anatomical appearance resembling real MVs (5.0/5), indicating that evaluators 'agreed' that these aspects of the model were appropriate for training. Evaluators 'somewhat agreed' that the overall model durability was appropriate for training (4.0/5) due to the mounting design. Qualitative differences in repair quality were notable between fellow and attending surgeon. 3D computer-aided design, 3D printing and fabrication techniques can be applied to fabricate affordable, high-quality educational models for technical training that are capable of differentiating proficiency levels among users. © The Author 2017

  10. The computer simulation of 3d gas dynamics in a gas centrifuge

    Science.gov (United States)

    Borman, V. D.; Bogovalov, S. V.; Borisevich, V. D.; Tronin, I. V.; Tronin, V. N.

    2016-09-01

    We argue on the basis of the results of 2D analysis of the gas flow in gas centrifuges that a reliable calculation of the circulation of the gas and gas content in the gas centrifuge is possible only in frameworks of 3D numerical simulation of gas dynamics in the gas centrifuge (hereafter GC). The group from National research nuclear university, MEPhI, has created a computer code for 3D simulation of the gas flow in GC. The results of the computer simulations of the gas flows in GC are presented. A model Iguassu centrifuge is explored for the simulations. A nonaxisymmetric gas flow is produced due to interaction of the hypersonic rotating flow with the scoops for extraction of the product and waste flows from the GC. The scoops produce shock waves penetrating into a working camera of the GC and form spiral waves there.

  11. The computer simulation of 3d gas dynamics in a gas centrifuge

    International Nuclear Information System (INIS)

    Borman, V D; Bogovalov, S V; Borisevich, V D; Tronin, I V; Tronin, V N

    2016-01-01

    We argue on the basis of the results of 2D analysis of the gas flow in gas centrifuges that a reliable calculation of the circulation of the gas and gas content in the gas centrifuge is possible only in frameworks of 3D numerical simulation of gas dynamics in the gas centrifuge (hereafter GC). The group from National research nuclear university, MEPhI, has created a computer code for 3D simulation of the gas flow in GC. The results of the computer simulations of the gas flows in GC are presented. A model Iguassu centrifuge is explored for the simulations. A nonaxisymmetric gas flow is produced due to interaction of the hypersonic rotating flow with the scoops for extraction of the product and waste flows from the GC. The scoops produce shock waves penetrating into a working camera of the GC and form spiral waves there. (paper)

  12. The Vajont disaster: a 3D numerical simulation for the slide and the waves

    Science.gov (United States)

    Rubino, Angelo; Androsov, Alexey; Vacondio, Renato; Zanchettin, Davide; Voltzinger, Naum

    2016-04-01

    A very high resolution O(5 m), 3D hydrostatic nonlinear numerical model was used to simulate the dynamics of both the slide and the surface waves produced during the Vajont disaster (north Italy, 1963), one of the major landslide-induced tsunamis ever documented. Different simulated wave phenomena like, e.g., maximum run-up on the opposite shore, maximum height, and water velocity were analyzed and compared with data available in literature, including the results of a fully 3D simulation obtained with a Smoothed Particle Hydrodynamic code. The difference between measured and simulated after-slide bathymetries was calculated and used in an attempt to quantify the relative magnitude and extension of rigid and fluid motion components during the event.

  13. 3D Radiative Transfer in Eta Carinae: Application of the SimpleX Algorithm to 3D SPH Simulations of Binary Colliding Winds

    Science.gov (United States)

    Clementel, N.; Madura, T. I.; Kruip, C. J. H.; Icke, V.; Gull, T. R.

    2014-01-01

    Eta Carinae is an ideal astrophysical laboratory for studying massive binary interactions and evolution, and stellar wind-wind collisions. Recent three-dimensional (3D) simulations set the stage for understanding the highly complex 3D flows in Eta Car. Observations of different broad high- and low-ionization forbidden emission lines provide an excellent tool to constrain the orientation of the system, the primary's mass-loss rate, and the ionizing flux of the hot secondary. In this work we present the first steps towards generating synthetic observations to compare with available and future HST/STIS data. We present initial results from full 3D radiative transfer simulations of the interacting winds in Eta Car. We use the SimpleX algorithm to post-process the output from 3D SPH simulations and obtain the ionization fractions of hydrogen and helium assuming three different mass-loss rates for the primary star. The resultant ionization maps of both species constrain the regions where the observed forbidden emission lines can form. Including collisional ionization is necessary to achieve a better description of the ionization states, especially in the areas shielded from the secondary's radiation. We find that reducing the primary's mass-loss rate increases the volume of ionized gas, creating larger areas where the forbidden emission lines can form. We conclude that post processing 3D SPH data with SimpleX is a viable tool to create ionization maps for Eta Car.

  14. Global and 3D spatial assessment of neuroinflammation in rodent models of Multiple Sclerosis.

    Directory of Open Access Journals (Sweden)

    Shashank Gupta

    Full Text Available Multiple Sclerosis (MS is a progressive autoimmune inflammatory and demyelinating disease of the central nervous system (CNS. T cells play a key role in the progression of neuroinflammation in MS and also in the experimental autoimmune encephalomyelitis (EAE animal models for the disease. A technology for quantitative and 3 dimensional (3D spatial assessment of inflammation in this and other CNS inflammatory conditions is much needed. Here we present a procedure for 3D spatial assessment and global quantification of the development of neuroinflammation based on Optical Projection Tomography (OPT. Applying this approach to the analysis of rodent models of MS, we provide global quantitative data of the major inflammatory component as a function of the clinical course. Our data demonstrates a strong correlation between the development and progression of neuroinflammation and clinical disease in several mouse and a rat model of MS refining the information regarding the spatial dynamics of the inflammatory component in EAE. This method provides a powerful tool to investigate the effect of environmental and genetic forces and for assessing the therapeutic effects of drug therapy in animal models of MS and other neuroinflammatory/neurodegenerative disorders.

  15. Rise time of proton cut-off energy in 2D and 3D PIC simulations

    Science.gov (United States)

    Babaei, J.; Gizzi, L. A.; Londrillo, P.; Mirzanejad, S.; Rovelli, T.; Sinigardi, S.; Turchetti, G.

    2017-04-01

    The Target Normal Sheath Acceleration regime for proton acceleration by laser pulses is experimentally consolidated and fairly well understood. However, uncertainties remain in the analysis of particle-in-cell simulation results. The energy spectrum is exponential with a cut-off, but the maximum energy depends on the simulation time, following different laws in two and three dimensional (2D, 3D) PIC simulations so that the determination of an asymptotic value has some arbitrariness. We propose two empirical laws for the rise time of the cut-off energy in 2D and 3D PIC simulations, suggested by a model in which the proton acceleration is due to a surface charge distribution on the target rear side. The kinetic energy of the protons that we obtain follows two distinct laws, which appear to be nicely satisfied by PIC simulations, for a model target given by a uniform foil plus a contaminant layer that is hydrogen-rich. The laws depend on two parameters: the scaling time, at which the energy starts to rise, and the asymptotic cut-off energy. The values of the cut-off energy, obtained by fitting 2D and 3D simulations for the same target and laser pulse configuration, are comparable. This suggests that parametric scans can be performed with 2D simulations since 3D ones are computationally very expensive, delegating their role only to a correspondence check. In this paper, the simulations are carried out with the PIC code ALaDyn by changing the target thickness L and the incidence angle α, with a fixed a0 = 3. A monotonic dependence, on L for normal incidence and on α for fixed L, is found, as in the experimental results for high temporal contrast pulses.

  16. GPU accelerated simulations of 3D deterministic particle transport using discrete ordinates method

    International Nuclear Information System (INIS)

    Gong Chunye; Liu Jie; Chi Lihua; Huang Haowei; Fang Jingyue; Gong Zhenghu

    2011-01-01

    Graphics Processing Unit (GPU), originally developed for real-time, high-definition 3D graphics in computer games, now provides great faculty in solving scientific applications. The basis of particle transport simulation is the time-dependent, multi-group, inhomogeneous Boltzmann transport equation. The numerical solution to the Boltzmann equation involves the discrete ordinates (S n ) method and the procedure of source iteration. In this paper, we present a GPU accelerated simulation of one energy group time-independent deterministic discrete ordinates particle transport in 3D Cartesian geometry (Sweep3D). The performance of the GPU simulations are reported with the simulations of vacuum boundary condition. The discussion of the relative advantages and disadvantages of the GPU implementation, the simulation on multi GPUs, the programming effort and code portability are also reported. The results show that the overall performance speedup of one NVIDIA Tesla M2050 GPU ranges from 2.56 compared with one Intel Xeon X5670 chip to 8.14 compared with one Intel Core Q6600 chip for no flux fixup. The simulation with flux fixup on one M2050 is 1.23 times faster than on one X5670.

  17. GPU accelerated simulations of 3D deterministic particle transport using discrete ordinates method

    Science.gov (United States)

    Gong, Chunye; Liu, Jie; Chi, Lihua; Huang, Haowei; Fang, Jingyue; Gong, Zhenghu

    2011-07-01

    Graphics Processing Unit (GPU), originally developed for real-time, high-definition 3D graphics in computer games, now provides great faculty in solving scientific applications. The basis of particle transport simulation is the time-dependent, multi-group, inhomogeneous Boltzmann transport equation. The numerical solution to the Boltzmann equation involves the discrete ordinates ( Sn) method and the procedure of source iteration. In this paper, we present a GPU accelerated simulation of one energy group time-independent deterministic discrete ordinates particle transport in 3D Cartesian geometry (Sweep3D). The performance of the GPU simulations are reported with the simulations of vacuum boundary condition. The discussion of the relative advantages and disadvantages of the GPU implementation, the simulation on multi GPUs, the programming effort and code portability are also reported. The results show that the overall performance speedup of one NVIDIA Tesla M2050 GPU ranges from 2.56 compared with one Intel Xeon X5670 chip to 8.14 compared with one Intel Core Q6600 chip for no flux fixup. The simulation with flux fixup on one M2050 is 1.23 times faster than on one X5670.

  18. Interactive virtual simulation using a 3D computer graphics model for microvascular decompression surgery.

    Science.gov (United States)

    Oishi, Makoto; Fukuda, Masafumi; Hiraishi, Tetsuya; Yajima, Naoki; Sato, Yosuke; Fujii, Yukihiko

    2012-09-01

    The purpose of this paper is to report on the authors' advanced presurgical interactive virtual simulation technique using a 3D computer graphics model for microvascular decompression (MVD) surgery. The authors performed interactive virtual simulation prior to surgery in 26 patients with trigeminal neuralgia or hemifacial spasm. The 3D computer graphics models for interactive virtual simulation were composed of the brainstem, cerebellum, cranial nerves, vessels, and skull individually created by the image analysis, including segmentation, surface rendering, and data fusion for data collected by 3-T MRI and 64-row multidetector CT systems. Interactive virtual simulation was performed by employing novel computer-aided design software with manipulation of a haptic device to imitate the surgical procedures of bone drilling and retraction of the cerebellum. The findings were compared with intraoperative findings. In all patients, interactive virtual simulation provided detailed and realistic surgical perspectives, of sufficient quality, representing the lateral suboccipital route. The causes of trigeminal neuralgia or hemifacial spasm determined by observing 3D computer graphics models were concordant with those identified intraoperatively in 25 (96%) of 26 patients, which was a significantly higher rate than the 73% concordance rate (concordance in 19 of 26 patients) obtained by review of 2D images only (p computer graphics model provided a realistic environment for performing virtual simulations prior to MVD surgery and enabled us to ascertain complex microsurgical anatomy.

  19. Dynamic earthquake rupture simulations on nonplanar faults embedded in 3D geometrically complex, heterogeneous elastic solids

    Energy Technology Data Exchange (ETDEWEB)

    Duru, Kenneth, E-mail: kduru@stanford.edu [Department of Geophysics, Stanford University, Stanford, CA (United States); Dunham, Eric M. [Department of Geophysics, Stanford University, Stanford, CA (United States); Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA (United States)

    2016-01-15

    Dynamic propagation of shear ruptures on a frictional interface in an elastic solid is a useful idealization of natural earthquakes. The conditions relating discontinuities in particle velocities across fault zones and tractions acting on the fault are often expressed as nonlinear friction laws. The corresponding initial boundary value problems are both numerically and computationally challenging. In addition, seismic waves generated by earthquake ruptures must be propagated for many wavelengths away from the fault. Therefore, reliable and efficient numerical simulations require both provably stable and high order accurate numerical methods. We present a high order accurate finite difference method for: a) enforcing nonlinear friction laws, in a consistent and provably stable manner, suitable for efficient explicit time integration; b) dynamic propagation of earthquake ruptures along nonplanar faults; and c) accurate propagation of seismic waves in heterogeneous media with free surface topography. We solve the first order form of the 3D elastic wave equation on a boundary-conforming curvilinear mesh, in terms of particle velocities and stresses that are collocated in space and time, using summation-by-parts (SBP) finite difference operators in space. Boundary and interface conditions are imposed weakly using penalties. By deriving semi-discrete energy estimates analogous to the continuous energy estimates we prove numerical stability. The finite difference stencils used in this paper are sixth order accurate in the interior and third order accurate close to the boundaries. However, the method is applicable to any spatial operator with a diagonal norm satisfying the SBP property. Time stepping is performed with a 4th order accurate explicit low storage Runge–Kutta scheme, thus yielding a globally fourth order accurate method in both space and time. We show numerical simulations on band limited self-similar fractal faults revealing the complexity of rupture

  20. Albedo and heat transport in 3-D model simulations of the early Archean climate

    Directory of Open Access Journals (Sweden)

    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.

  1. Neutron-induced complex reaction analysis with 3D nuclear track simulation

    International Nuclear Information System (INIS)

    Sajo-Bohus, L.; Palfalvi, J.K.; Akatov, Yu.; Arevalo, O.; Greaves, E.D.; Nemeth, P.; Palacios, D.; Szabo, J.; Eoerdoegh, I.

    2005-01-01

    Complex (multiple) etched tracks are analysed through digitised images and 3D simulation by a purpose-built algorithm. From a binary track image an unfolding procedure is followed to generate a 3D track model, from which several track parameters are estimated. The method presented here allows the deposited energy, that originated from particle fragmentation or carbon spallation by means of induced tracks in commercially available PADC detectors, to be estimated. Results of evaluated nuclear tracks related to 12 C (n,3αn ' ) reaction are presented here. The detectors were exposed on the ISS in 2001

  2. 3D dynamic simulation of crack propagation in extracorporeal shock wave lithotripsy

    Science.gov (United States)

    Wijerathne, M. L. L.; Hori, Muneo; Sakaguchi, Hide; Oguni, Kenji

    2010-06-01

    Some experimental observations of Shock Wave Lithotripsy(SWL), which include 3D dynamic crack propagation, are simulated with the aim of reproducing fragmentation of kidney stones with SWL. Extracorporeal shock wave lithotripsy (ESWL) is the fragmentation of kidney stones by focusing an ultrasonic pressure pulse onto the stones. 3D models with fine discretization are used to accurately capture the high amplitude shear shock waves. For solving the resulting large scale dynamic crack propagation problem, PDS-FEM is used; it provides numerically efficient failure treatments. With a distributed memory parallel code of PDS-FEM, experimentally observed 3D photoelastic images of transient stress waves and crack patterns in cylindrical samples are successfully reproduced. The numerical crack patterns are in good agreement with the experimental ones, quantitatively. The results shows that the high amplitude shear waves induced in solid, by the lithotriptor generated shock wave, play a dominant role in stone fragmentation.

  3. Modelling and Manufacturing of a 3D Printed Trachea for Cricothyroidotomy Simulation.

    Science.gov (United States)

    Doucet, Gregory; Ryan, Stephen; Bartellas, Michael; Parsons, Michael; Dubrowski, Adam; Renouf, Tia

    2017-08-18

    Cricothyroidotomy is a life-saving medical procedure that allows for tracheal intubation. Most current cricothyroidotomy simulation models are either expensive or not anatomically accurate and provide the learner with an unrealistic simulation experience. The goal of this project is to improve current simulation techniques by utilizing rapid prototyping using 3D printing technology and expert opinions to develop inexpensive and anatomically accurate trachea simulators. In doing so, emergency cricothyroidotomy simulation can be made accessible, accurate, cost-effective and reproducible. Three-dimensional modelling software was used in conjunction with a desktop three-dimensional (3D) printer to design and manufacture an anatomically accurate model of the cartilage within the trachea (thyroid cartilage, cricoid cartilage, and the tracheal rings). The initial design was based on dimensions found in studies of tracheal anatomical configuration. This ensured that the landmarking necessary for emergency cricothyroidotomies was designed appropriately. Several revisions of the original model were made based on informal opinion from medical professionals to establish appropriate anatomical accuracy of the model for use in rural/remote cricothyroidotomy simulation. Using an entry-level desktop 3D printer, a low cost tracheal model was successfully designed that can be printed in less than three hours for only $1.70 Canadian dollars (CAD). Due to its anatomical accuracy, flexibility and durability, this model is great for use in emergency medicine simulation training. Additionally, the model can be assembled in conjunction with a membrane to simulate tracheal ligaments. Skin has been simulated as well to enhance the realism of the model. The result is an accurate simulation that will provide users with an anatomically correct model to practice important skills used in emergency airway surgery, specifically landmarking, incision and intubation. This design is a novel and easy

  4. Differences in 3D vs. 2D analysis in lumbar spinal fusion simulations.

    Science.gov (United States)

    Hsu, Hung-Wei; Bashkuev, Maxim; Pumberger, Matthias; Schmidt, Hendrik

    2018-04-27

    Lumbar interbody fusion is currently the gold standard in treating patients with disc degeneration or segmental instability. Despite it having been used for several decades, the non-union rate remains high. A failed fusion is frequently attributed to an inadequate mechanical environment after instrumentation. Finite element (FE) models can provide insights into the mechanics of the fusion process. Previous fusion simulations using FE models showed that the geometries and material of the cage can greatly influence the fusion outcome. However, these studies used axisymmetric models which lacked realistic spinal geometries. Therefore, different modeling approaches were evaluated to understand the bone-formation process. Three FE models of the lumbar motion segment (L4-L5) were developed: 2D, Sym-3D and Nonsym-3D. The fusion process based on existing mechano-regulation algorithms using the FE simulations to evaluate the mechanical environment was then integrated into these models. In addition, the influence of different lordotic angles (5, 10 and 15°) was investigated. The volume of newly formed bone, the axial stiffness of the whole segment and bone distribution inside and surrounding the cage were evaluated. In contrast to the Nonsym-3D, the 2D and Sym-3D models predicted excessive bone formation prior to bridging (peak values with 36 and 9% higher than in equilibrium, respectively). The 3D models predicted a more uniform bone distribution compared to the 2D model. The current results demonstrate the crucial role of the realistic 3D geometry of the lumbar motion segment in predicting bone formation after lumbar spinal fusion. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. The simulation of 3D microcalcification clusters in 2D digital mammography and breast tomosynthesis

    International Nuclear Information System (INIS)

    Shaheen, Eman; Van Ongeval, Chantal; Zanca, Federica; Cockmartin, Lesley; Marshall, Nicholas; Jacobs, Jurgen; Young, Kenneth C.; Dance, David R.; Bosmans, Hilde

    2011-01-01

    Purpose: This work proposes a new method of building 3D models of microcalcification clusters and describes the validation of their realistic appearance when simulated into 2D digital mammograms and into breast tomosynthesis images. Methods: A micro-CT unit was used to scan 23 breast biopsy specimens of microcalcification clusters with malignant and benign characteristics and their 3D reconstructed datasets were segmented to obtain 3D models of microcalcification clusters. These models were then adjusted for the x-ray spectrum used and for the system resolution and simulated into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. Six radiologists were asked to distinguish between 40 real and 40 simulated clusters of microcalcifications in two separate studies on 2D mammography and tomosynthesis datasets. Receiver operating characteristic (ROC) analysis was used to test the ability of each observer to distinguish between simulated and real microcalcification clusters. The kappa statistic was applied to assess how often the individual simulated and real microcalcification clusters had received similar scores (''agreement'') on their realistic appearance in both modalities. This analysis was performed for all readers and for the real and the simulated group of microcalcification clusters separately. ''Poor'' agreement would reflect radiologists' confusion between simulated and real clusters, i.e., lesions not systematically evaluated in both modalities as either simulated or real, and would therefore be interpreted as a success of the present models. Results: The area under the ROC curve, averaged over the observers, was 0.55 (95% confidence interval [0.44, 0.66]) for the 2D study, and 0.46 (95% confidence interval [0.29, 0.64]) for the tomosynthesis study, indicating no statistically significant difference between real and simulated

  6. Parallel 3D Simulation of Seismic Wave Propagation in the Structure of Nobi Plain, Central Japan

    Science.gov (United States)

    Kotani, A.; Furumura, T.; Hirahara, K.

    2003-12-01

    We performed large-scale parallel simulations of the seismic wave propagation to understand the complex wave behavior in the 3D basin structure of the Nobi Plain, which is one of the high population cities in central Japan. In this area, many large earthquakes occurred in the past, such as the 1891 Nobi earthquake (M8.0), the 1944 Tonankai earthquake (M7.9) and the 1945 Mikawa earthquake (M6.8). In order to mitigate the potential disasters for future earthquakes, 3D subsurface structure of Nobi Plain has recently been investigated by local governments. We referred to this model together with bouguer anomaly data to construct a detail 3D basin structure model for Nobi plain, and conducted computer simulations of ground motions. We first evaluated the ground motions for two small earthquakes (M4~5); one occurred just beneath the basin edge at west, and the other occurred at south. The ground motions from these earthquakes were well recorded by the strong motion networks; K-net, Kik-net, and seismic intensity instruments operated by local governments. We compare the observed seismograms with simulations to validate the 3D model. For the 3D simulation we sliced the 3D model into a number of layers to assign to many processors for concurrent computing. The equation of motions are solved using a high order (32nd) staggered-grid FDM in horizontal directions, and a conventional (4th-order) FDM in vertical direction with the MPI inter-processor communications between neighbor region. The simulation model is 128km by 128km by 43km, which is discritized at variable grid size of 62.5-125m in horizontal directions and of 31.25-62.5m in vertical direction. We assigned a minimum shear wave velocity is Vs=0.4km/s, at the top of the sedimentary basin. The seismic sources for the small events are approximated by double-couple point source and we simulate the seismic wave propagation at maximum frequency of 2Hz. We used the Earth Simulator (JAMSTEC, Yokohama Inst) to conduct such

  7. Development of discrete gas kinetic scheme for simulation of 3D viscous incompressible and compressible flows

    Science.gov (United States)

    Yang, L. M.; Shu, C.; Wang, Y.; Sun, Y.

    2016-08-01

    The sphere function-based gas kinetic scheme (GKS), which was presented by Shu and his coworkers [23] for simulation of inviscid compressible flows, is extended to simulate 3D viscous incompressible and compressible flows in this work. Firstly, we use certain discrete points to represent the spherical surface in the phase velocity space. Then, integrals along the spherical surface for conservation forms of moments, which are needed to recover 3D Navier-Stokes equations, are approximated by integral quadrature. The basic requirement is that these conservation forms of moments can be exactly satisfied by weighted summation of distribution functions at discrete points. It was found that the integral quadrature by eight discrete points on the spherical surface, which forms the D3Q8 discrete velocity model, can exactly match the integral. In this way, the conservative variables and numerical fluxes can be computed by weighted summation of distribution functions at eight discrete points. That is, the application of complicated formulations resultant from integrals can be replaced by a simple solution process. Several numerical examples including laminar flat plate boundary layer, 3D lid-driven cavity flow, steady flow through a 90° bending square duct, transonic flow around DPW-W1 wing and supersonic flow around NACA0012 airfoil are chosen to validate the proposed scheme. Numerical results demonstrate that the present scheme can provide reasonable numerical results for 3D viscous flows.

  8. A simulated training model for laparoscopic pyloromyotomy: Is 3D printing the way of the future?

    Science.gov (United States)

    Williams, Andrew; McWilliam, Morgan; Ahlin, James; Davidson, Jacob; Quantz, Mackenzie A; Bütter, Andreana

    2018-05-01

    Hypertrophic pyloric stenosis (HPS) is a common neonatal condition treated with open or laparoscopic pyloromyotomy. 3D-printed organs offer realistic simulations to practice surgical techniques. The purpose of this study was to validate a 3D HPS stomach model and assess model reliability and surgical realism. Medical students, general surgery residents, and adult and pediatric general surgeons were recruited from a single center. Participants were videotaped three times performing a laparoscopic pyloromyotomy using box trainers and 3D-printed stomachs. Attempts were graded independently by three reviewers using GOALS and Task Specific Assessments (TSA). Participants were surveyed using the Index of Agreement of Assertions on Model Accuracy (IAAMA). Participants reported their experience levels as novice (22%), inexperienced (26%), intermediate (19%), and experienced (33%). Interrater reliability was similar for overall average GOALS and TSA scores. There was a significant improvement in GOALS (p3D-printed stomach model for simulated laparoscopic pyloromyotomy is a useful training tool for learners to improve laparoscopic skills. The GOALS and TSA provide reliable technical skills assessments. II. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Numerical simulation of 3D boundary-driven acoustic streaming in microfluidic devices.

    Science.gov (United States)

    Lei, Junjun; Hill, Martyn; Glynne-Jones, Peter

    2014-02-07

    This article discusses three-dimensional (3D) boundary-driven streaming in acoustofluidic devices. Firstly, the 3D Rayleigh streaming pattern in a microchannel is simulated and its effect on the movement of microparticles of various sizes is demonstrated. The results obtained from this model show good comparisons with 3D experimental visualisations and demonstrate the fully 3D nature of the acoustic streaming field and the associated acoustophoretic motion of microparticles in acoustofluidic devices. This method is then applied to another acoustofluidic device in order to gain insights into an unusual in-plane streaming pattern. The origin of this streaming has not been fully described and its characteristics cannot be explained from the classical theory of Rayleigh streaming. The simulated in-plane streaming pattern was in good agreement with the experimental visualisation. The mechanism behind it is shown to be related to the active sound intensity field, which supports our previous findings on the mechanism of the in-plane acoustic streaming pattern visualised and modelled in a thin-layered capillary device.

  10. 3D printed simulation models based on real patient situations for hands-on practice.

    Science.gov (United States)

    Kröger, E; Dekiff, M; Dirksen, D

    2017-11-01

    During the last few years, the curriculum of many dentistry schools in Germany has been reorganised. Two key aspects of the applied changes are the integration of up-to-date teaching methods and the promotion of interdisciplinarity. To support these efforts, an approach to fabricating individualised simulation models for hands-on courses employing 3D printing is presented. The models are based on real patients, thus providing students a more realistic preparation for real clinical situations. As a wide variety of dental procedures can be implemented, the simulation models can also contribute to a more interdisciplinary dental education. The data used for the construction of the models were acquired by 3D surface scanning. The data were further processed with 3D modelling software. Afterwards, the models were fabricated by 3D printing with the PolyJet technique. Three models serve as examples: a prosthodontic model for training veneer preparation, a conservative model for practicing dental bonding and an interdisciplinary model featuring carious teeth and an insufficient crown. The third model was evaluated in a hands-on course with 22 fourth-year dental students. The students answered a questionnaire and gave their personal opinion. Whilst the concept of the model received very positive feedback, some aspects of the implementation were criticised. We discuss these observations and suggest ways for further improvement. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. 3D thermal modeling of TRISO fuel coupled with neutronic simulation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jianwei [Los Alamos National Laboratory; Uddin, Rizwan [UNIV OF ILLINIOS

    2010-01-01

    The Very High Temperature Gas Reactor (VHTR) is widely considered as one of the top candidates identified in the Next Generation Nuclear Power-plant (NGNP) Technology Roadmap under the U.S . Depanment of Energy's Generation IV program. TRlSO particle is a common element among different VHTR designs and its performance is critical to the safety and reliability of the whole reactor. A TRISO particle experiences complex thermo-mechanical changes during reactor operation in high temperature and high burnup conditions. TRISO fuel performance analysis requires evaluation of these changes on micro scale. Since most of these changes are temperature dependent, 3D thermal modeling of TRISO fuel is a crucial step of the whole analysis package. In this paper, a 3D numerical thermal model was developed to calculate temperature distribution inside TRISO and pebble under different scenarios. 3D simulation is required because pebbles or TRISOs are always subjected to asymmetric thermal conditions since they are randomly packed together. The numerical model was developed using finite difference method and it was benchmarked against ID analytical results and also results reported from literature. Monte-Carlo models were set up to calculate radial power density profile. Complex convective boundary condition was applied on the pebble outer surface. Three reactors were simulated using this model to calculate temperature distribution under different power levels. Two asymmetric boundary conditions were applied to the pebble to test the 3D capabilities. A gas bubble was hypothesized inside the TRISO kernel and 3D simulation was also carried out under this scenario. Intuition-coherent results were obtained and reported in this paper.

  12. Real-time 3D radiation risk assessment supporting simulation of work in nuclear environments

    International Nuclear Information System (INIS)

    Szoke, I; Louka, M N; Bryntesen, T R; Bratteli, J; Edvardsen, S T; RøEitrheim, K K; Bodor, K

    2014-01-01

    This paper describes the latest developments at the Institute for Energy Technology (IFE) in Norway, in the field of real-time 3D (three-dimensional) radiation risk assessment for the support of work simulation in nuclear environments. 3D computer simulation can greatly facilitate efficient work planning, briefing, and training of workers. It can also support communication within and between work teams, and with advisors, regulators, the media and public, at all the stages of a nuclear installation’s lifecycle. Furthermore, it is also a beneficial tool for reviewing current work practices in order to identify possible gaps in procedures, as well as to support the updating of international recommendations, dissemination of experience, and education of the current and future generation of workers. IFE has been involved in research and development into the application of 3D computer simulation and virtual reality (VR) technology to support work in radiological environments in the nuclear sector since the mid 1990s. During this process, two significant software tools have been developed, the VRdose system and the Halden Planner, and a number of publications have been produced to contribute to improving the safety culture in the nuclear industry. This paper describes the radiation risk assessment techniques applied in earlier versions of the VRdose system and the Halden Planner, for visualising radiation fields and calculating dose, and presents new developments towards implementing a flexible and up-to-date dosimetric package in these 3D software tools, based on new developments in the field of radiation protection. The latest versions of these 3D tools are capable of more accurate risk estimation, permit more flexibility via a range of user choices, and are applicable to a wider range of irradiation situations than their predecessors. (paper)

  13. Real-time 3D radiation risk assessment supporting simulation of work in nuclear environments.

    Science.gov (United States)

    Szőke, I; Louka, M N; Bryntesen, T R; Bratteli, J; Edvardsen, S T; RøEitrheim, K K; Bodor, K

    2014-06-01

    This paper describes the latest developments at the Institute for Energy Technology (IFE) in Norway, in the field of real-time 3D (three-dimensional) radiation risk assessment for the support of work simulation in nuclear environments. 3D computer simulation can greatly facilitate efficient work planning, briefing, and training of workers. It can also support communication within and between work teams, and with advisors, regulators, the media and public, at all the stages of a nuclear installation's lifecycle. Furthermore, it is also a beneficial tool for reviewing current work practices in order to identify possible gaps in procedures, as well as to support the updating of international recommendations, dissemination of experience, and education of the current and future generation of workers.IFE has been involved in research and development into the application of 3D computer simulation and virtual reality (VR) technology to support work in radiological environments in the nuclear sector since the mid 1990s. During this process, two significant software tools have been developed, the VRdose system and the Halden Planner, and a number of publications have been produced to contribute to improving the safety culture in the nuclear industry.This paper describes the radiation risk assessment techniques applied in earlier versions of the VRdose system and the Halden Planner, for visualising radiation fields and calculating dose, and presents new developments towards implementing a flexible and up-to-date dosimetric package in these 3D software tools, based on new developments in the field of radiation protection. The latest versions of these 3D tools are capable of more accurate risk estimation, permit more flexibility via a range of user choices, and are applicable to a wider range of irradiation situations than their predecessors.

  14. 3D full-loop simulation of an industrial-scale circulating fluidized boiler

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Bona; Zhang, Nan; Wang, Wei; Li, Jinghai [Chinese Academy of Sciences, Beijing (China). State Key Lab. of Multi-phase Complex Systems

    2013-07-01

    In this study, 3D full-loop simulations of a CFB boiler are carried out. FLUENT {sup registered} 6.3 is used as the solver, where an Eulerian multiphase model with EMMS-based drag model is employed. The wide particle size distribution are considered and divided into several groups to better represent the polydisperse behavior of ash particles. The simulation shows that, compared to the conventional drag model, EMMS-based model predicts more reasonable pressure drop of furnace and larger slip velocity at the lower elevations of the furnace. Further work is under way to improve the full-loop simulation.

  15. Random Telegraph Signal Amplitudes in Sub 100 nm (Decanano) MOSFETs: A 3D 'Atomistic' Simulation Study

    Science.gov (United States)

    Asenov, Asen; Balasubramaniam, R.; Brown, A. R.; Davies, J. H.; Saini, Subhash

    2000-01-01

    In this paper we use 3D simulations to study the amplitudes of random telegraph signals (RTS) associated with the trapping of a single carrier in interface states in the channel of sub 100 nm (decanano) MOSFETs. Both simulations using continuous doping charge and random discrete dopants in the active region of the MOSFETs are presented. We have studied the dependence of the RTS amplitudes on the position of the trapped charge in the channel and on the device design parameters. We have observed a significant increase in the maximum RTS amplitude when discrete random dopants are employed in the simulations.

  16. 3D segmentation of scintigraphic images with validation on realistic GATE simulations

    International Nuclear Information System (INIS)

    Burg, Samuel

    2011-01-01

    The objective of this thesis was to propose a new 3D segmentation method for scintigraphic imaging. The first part of the work was to simulate 3D volumes with known ground truth in order to validate a segmentation method over other. Monte-Carlo simulations were performed using the GATE software (Geant4 Application for Emission Tomography). For this, we characterized and modeled the gamma camera 'γ Imager' Biospace"T"M by comparing each measurement from a simulated acquisition to his real equivalent. The 'low level' segmentation tool that we have developed is based on a modeling of the levels of the image by probabilistic mixtures. Parameters estimation is done by an SEM algorithm (Stochastic Expectation Maximization). The 3D volume segmentation is achieved by an ICM algorithm (Iterative Conditional Mode). We compared the segmentation based on Gaussian and Poisson mixtures to segmentation by thresholding on the simulated volumes. This showed the relevance of the segmentations obtained using probabilistic mixtures, especially those obtained with Poisson mixtures. Those one has been used to segment real "1"8FDG PET images of the brain and to compute descriptive statistics of the different tissues. In order to obtain a 'high level' segmentation method and find anatomical structures (necrotic part or active part of a tumor, for example), we proposed a process based on the point processes formalism. A feasibility study has yielded very encouraging results. (author) [fr

  17. A 3D virtual reality simulator for training of minimally invasive surgery.

    Science.gov (United States)

    Mi, Shao-Hua; Hou, Zeng-Gunag; Yang, Fan; Xie, Xiao-Liang; Bian, Gui-Bin

    2014-01-01

    For the last decade, remarkable progress has been made in the field of cardiovascular disease treatment. However, these complex medical procedures require a combination of rich experience and technical skills. In this paper, a 3D virtual reality simulator for core skills training in minimally invasive surgery is presented. The system can generate realistic 3D vascular models segmented from patient datasets, including a beating heart, and provide a real-time computation of force and force feedback module for surgical simulation. Instruments, such as a catheter or guide wire, are represented by a multi-body mass-spring model. In addition, a realistic user interface with multiple windows and real-time 3D views are developed. Moreover, the simulator is also provided with a human-machine interaction module that gives doctors the sense of touch during the surgery training, enables them to control the motion of a virtual catheter/guide wire inside a complex vascular model. Experimental results show that the simulator is suitable for minimally invasive surgery training.

  18. 3D Simulation of Multiple Simultaneous Hydraulic Fractures with Different Initial Lengths in Rock

    Science.gov (United States)

    Tang, X.; Rayudu, N. M.; Singh, G.

    2017-12-01

    Hydraulic fracturing is widely used technique for extracting shale gas. During this process, fractures with various initial lengths are induced in rock mass with hydraulic pressure. Understanding the mechanism of propagation and interaction between these induced hydraulic cracks is critical for optimizing the fracking process. In this work, numerical results are presented for investigating the effect of in-situ parameters and fluid properties on growth and interaction of multi simultaneous hydraulic fractures. A fully coupled 3D fracture simulator, TOUGH- GFEM is used for simulating the effect of different vital parameters, including in-situ stress, initial fracture length, fracture spacing, fluid viscosity and flow rate on induced hydraulic fractures growth. This TOUGH-GFEM simulator is based on 3D finite volume method (FVM) and partition of unity element method (PUM). Displacement correlation method (DCM) is used for calculating multi - mode (Mode I, II, III) stress intensity factors. Maximum principal stress criteria is used for crack propagation. Key words: hydraulic fracturing, TOUGH, partition of unity element method , displacement correlation method, 3D fracturing simulator

  19. 3D Navier-Stokes simulations of a rotor designed for maximum aerodynamic efficiency

    DEFF Research Database (Denmark)

    Johansen, Jeppe; Madsen Aagaard, Helge; Gaunaa, Mac

    2007-01-01

    a constant load was assumed. The rotor design was obtained using an Actuator Disc model and was subsequently verified using both a free wake Lifting Line method and a full 3D Navier-Stokes solver. Excellent agreement was obtained using the three models. Global mechanical power coefficient, CP, reached...... a value of slightly above 0.51, while global thrust coefficient, CT, was 0.87. The local power coefficient, Cp, increased to slightly above the Betz limit on the inner part of the rotor as well as the local thrust coefficient, Ct, increased to a value above 1.1. This agrees well with the theory of de...

  20. 3D spatially-adaptive canonical correlation analysis: Local and global methods.

    Science.gov (United States)

    Yang, Zhengshi; Zhuang, Xiaowei; Sreenivasan, Karthik; Mishra, Virendra; Curran, Tim; Byrd, Richard; Nandy, Rajesh; Cordes, Dietmar

    2018-04-01

    Local spatially-adaptive canonical correlation analysis (local CCA) with spatial constraints has been introduced to fMRI multivariate analysis for improved modeling of activation patterns. However, current algorithms require complicated spatial constraints that have only been applied to 2D local neighborhoods because the computational time would be exponentially increased if the same method is applied to 3D spatial neighborhoods. In this study, an efficient and accurate line search sequential quadratic programming (SQP) algorithm has been developed to efficiently solve the 3D local CCA problem with spatial constraints. In addition, a spatially-adaptive kernel CCA (KCCA) method is proposed to increase accuracy of fMRI activation maps. With oriented 3D spatial filters anisotropic shapes can be estimated during the KCCA analysis of fMRI time courses. These filters are orientation-adaptive leading to rotational invariance to better match arbitrary oriented fMRI activation patterns, resulting in improved sensitivity of activation detection while significantly reducing spatial blurring artifacts. The kernel method in its basic form does not require any spatial constraints and analyzes the whole-brain fMRI time series to construct an activation map. Finally, we have developed a penalized kernel CCA model that involves spatial low-pass filter constraints to increase the specificity of the method. The kernel CCA methods are compared with the standard univariate method and with two different local CCA methods that were solved by the SQP algorithm. Results show that SQP is the most efficient algorithm to solve the local constrained CCA problem, and the proposed kernel CCA methods outperformed univariate and local CCA methods in detecting activations for both simulated and real fMRI episodic memory data. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. 3D immersive patient simulators and their impact on learning success: a thematic review.

    Science.gov (United States)

    Kleinert, Robert; Wahba, Roger; Chang, De-Hua; Plum, Patrick; Hölscher, Arnulf H; Stippel, Dirk L

    2015-04-08

    Immersive patient simulators (IPSs) combine the simulation of virtual patients with a three-dimensional (3D) environment and, thus, allow an illusionary immersion into a synthetic world, similar to computer games. Playful learning in a 3D environment is motivating and allows repetitive training and internalization of medical workflows (ie, procedural knowledge) without compromising real patients. The impact of this innovative educational concept on learning success requires review of feasibility and validity. It was the aim of this paper to conduct a survey of all immersive patient simulators currently available. In addition, we address the question of whether the use of these simulators has an impact on knowledge gain by summarizing the existing validation studies. A systematic literature search via PubMed was performed using predefined inclusion criteria (ie, virtual worlds, focus on education of medical students, validation testing) to identify all available simulators. Validation testing was defined as the primary end point. There are currently 13 immersive patient simulators available. Of these, 9 are Web-based simulators and represent feasibility studies. None of these simulators are used routinely for student education. The workstation-based simulators are commercially driven and show a higher quality in terms of graphical quality and/or data content. Out of the studies, 1 showed a positive correlation between simulated content and real content (ie, content validity). There was a positive correlation between the outcome of simulator training and alternative training methods (ie, concordance validity), and a positive coherence between measured outcome and future professional attitude and performance (ie, predictive validity). IPSs can promote learning and consolidation of procedural knowledge. The use of immersive patient simulators is still marginal, and technical and educational approaches are heterogeneous. Academic-driven IPSs could possibly enhance the

  2. 3D SPH numerical simulation of the wave generated by the Vajont rockslide

    Science.gov (United States)

    Vacondio, R.; Mignosa, P.; Pagani, S.

    2013-09-01

    A 3D numerical modeling of the wave generated by the Vajont slide, one of the most destructive ever occurred, is presented in this paper. A meshless Lagrangian Smoothed Particle Hydrodynamics (SPH) technique was adopted to simulate the highly fragmented violent flow generated by the falling slide in the artificial reservoir. The speed-up achievable via General Purpose Graphic Processing Units (GP-GPU) allowed to adopt the adequate resolution to describe the phenomenon. The comparison with the data available in literature showed that the results of the numerical simulation reproduce satisfactorily the maximum run-up, also the water surface elevation in the residual lake after the event. Moreover, the 3D velocity field of the flow during the event and the discharge hydrograph which overtopped the dam, were obtained.

  3. 3D MHD simulations of pellet injection and disruptions in tokamak plasmas

    International Nuclear Information System (INIS)

    Strauss, H.R.; Park, W.; Belova, E.; Fu, G.Y.; Sugiyama, L.E.

    2001-01-01

    Nonlinear MHD simulation results of pellet injection show that MHD forces can accelerate large pellets, injected on the high field side of a tokamak, to the plasma center. Magnetic reconnection can produce a reverse shear q profile. Ballooning instability caused by pellets is also reduced by high field side injection. Studies are also reported of the current quench phase of disruptions, which can cause 3D halo currents and runaway electrons. (author)

  4. 3D MHD simulations of pellet injection and disruptions in tokamak plasmas

    International Nuclear Information System (INIS)

    Strauss, H.R.; Park, W.; Belova, E.; Fu, G.Y.; Sugiyama, L.E.

    1999-01-01

    Nonlinear MHD simulation results of pellet injection show that MHD forces can accelerate large pellets, injected on the high field side of a tokamak, to the plasma center. Magnetic reconnection can produce a reverse shear q profile. Ballooning instability caused by pellets is also reduced by high field side injection. Studies are also reported of the current quench phase of disruptions, which can cause 3D halo currents and runaway electrons. (author)

  5. 3D Printed Surgical Simulation Models as educational tool by maxillofacial surgeons.

    Science.gov (United States)

    Werz, S M; Zeichner, S J; Berg, B-I; Zeilhofer, H-F; Thieringer, F

    2018-02-26

    The aim of this study was to evaluate whether inexpensive 3D models can be suitable to train surgical skills to dental students or oral and maxillofacial surgery residents. Furthermore, we wanted to know which of the most common filament materials, acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA), can better simulate human bone according to surgeons' subjective perceptions. Upper and lower jaw models were produced with common 3D desktop printers, ABS and PLA filament and silicon rubber for soft tissue simulation. Those models were given to 10 blinded, experienced maxillofacial surgeons to perform sinus lift and wisdom teeth extraction. Evaluation was made using a questionnaire. Because of slightly different density and filament prices, each silicon-covered model costs between 1.40-1.60 USD (ABS) and 1.80-2.00 USD (PLA) based on 2017 material costs. Ten experienced raters took part in the study. All raters deemed the models suitable for surgical education. No significant differences between ABS and PLA were found, with both having distinct advantages. The study demonstrated that 3D printing with inexpensive printing filaments is a promising method for training oral and maxillofacial surgery residents or dental students in selected surgical procedures. With a simple and cost-efficient manufacturing process, models of actual patient cases can be produced on a small scale, simulating many kinds of surgical procedures. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Generating classes of 3D virtual mandibles for AR-based medical simulation.

    Science.gov (United States)

    Hippalgaonkar, Neha R; Sider, Alexa D; Hamza-Lup, Felix G; Santhanam, Anand P; Jaganathan, Bala; Imielinska, Celina; Rolland, Jannick P

    2008-01-01

    Simulation and modeling represent promising tools for several application domains from engineering to forensic science and medicine. Advances in 3D imaging technology convey paradigms such as augmented reality (AR) and mixed reality inside promising simulation tools for the training industry. Motivated by the requirement for superimposing anatomically correct 3D models on a human patient simulator (HPS) and visualizing them in an AR environment, the purpose of this research effort was to develop and validate a method for scaling a source human mandible to a target human mandible within a 2 mm root mean square (RMS) error. Results show that, given a distance between 2 same landmarks on 2 different mandibles, a relative scaling factor may be computed. Using this scaling factor, results show that a 3D virtual mandible model can be made morphometrically equivalent to a real target-specific mandible within a 1.30 mm RMS error. The virtual mandible may be further used as a reference target for registering other anatomic models, such as the lungs, on the HPS. Such registration will be made possible by physical constraints among the mandible and the spinal column in the horizontal normal rest position.

  7. Modeling and simulating the adaptive electrical properties of stochastic polymeric 3D networks

    International Nuclear Information System (INIS)

    Sigala, R; Smerieri, A; Camorani, P; Schüz, A; Erokhin, V

    2013-01-01

    Memristors are passive two-terminal circuit elements that combine resistance and memory. Although in theory memristors are a very promising approach to fabricate hardware with adaptive properties, there are only very few implementations able to show their basic properties. We recently developed stochastic polymeric matrices with a functionality that evidences the formation of self-assembled three-dimensional (3D) networks of memristors. We demonstrated that those networks show the typical hysteretic behavior observed in the ‘one input-one output’ memristive configuration. Interestingly, using different protocols to electrically stimulate the networks, we also observed that their adaptive properties are similar to those present in the nervous system. Here, we model and simulate the electrical properties of these self-assembled polymeric networks of memristors, the topology of which is defined stochastically. First, we show that the model recreates the hysteretic behavior observed in the real experiments. Second, we demonstrate that the networks modeled indeed have a 3D instead of a planar functionality. Finally, we show that the adaptive properties of the networks depend on their connectivity pattern. Our model was able to replicate fundamental qualitative behavior of the real organic 3D memristor networks; yet, through the simulations, we also explored other interesting properties, such as the relation between connectivity patterns and adaptive properties. Our model and simulations represent an interesting tool to understand the very complex behavior of self-assembled memristor networks, which can finally help to predict and formulate hypotheses for future experiments. (paper)

  8. Multiple-point statistical simulation for hydrogeological models: 3-D training image development and conditioning strategies

    Science.gov (United States)

    Høyer, Anne-Sophie; Vignoli, Giulio; Mejer Hansen, Thomas; Thanh Vu, Le; Keefer, Donald A.; Jørgensen, Flemming

    2017-12-01

    Most studies on the application of geostatistical simulations based on multiple-point statistics (MPS) to hydrogeological modelling focus on relatively fine-scale models and concentrate on the estimation of facies-level structural uncertainty. Much less attention is paid to the use of input data and optimal construction of training images. For instance, even though the training image should capture a set of spatial geological characteristics to guide the simulations, the majority of the research still relies on 2-D or quasi-3-D training images. In the present study, we demonstrate a novel strategy for 3-D MPS modelling characterized by (i) realistic 3-D training images and (ii) an effective workflow for incorporating a diverse group of geological and geophysical data sets. The study covers an area of 2810 km2 in the southern part of Denmark. MPS simulations are performed on a subset of the geological succession (the lower to middle Miocene sediments) which is characterized by relatively uniform structures and dominated by sand and clay. The simulated domain is large and each of the geostatistical realizations contains approximately 45 million voxels with size 100 m × 100 m × 5 m. Data used for the modelling include water well logs, high-resolution seismic data, and a previously published 3-D geological model. We apply a series of different strategies for the simulations based on data quality, and develop a novel method to effectively create observed spatial trends. The training image is constructed as a relatively small 3-D voxel model covering an area of 90 km2. We use an iterative training image development strategy and find that even slight modifications in the training image create significant changes in simulations. Thus, this study shows how to include both the geological environment and the type and quality of input information in order to achieve optimal results from MPS modelling. We present a practical workflow to build the training image and

  9. 3D simulation of friction stir welding based on movable cellular automaton method

    Science.gov (United States)

    Eremina, Galina M.

    2017-12-01

    The paper is devoted to a 3D computer simulation of the peculiarities of material flow taking place in friction stir welding (FSW). The simulation was performed by the movable cellular automaton (MCA) method, which is a representative of particle methods in mechanics. Commonly, the flow of material in FSW is simulated based on computational fluid mechanics, assuming the material as continuum and ignoring its structure. The MCA method considers a material as an ensemble of bonded particles. The rupture of interparticle bonds and the formation of new bonds enable simulations of crack nucleation and healing as well as mas mixing and microwelding. The simulation results showed that using pins of simple shape (cylinder, cone, and pyramid) without a shoulder results in small displacements of plasticized material in workpiece thickness directions. Nevertheless, the optimal ratio of longitudinal velocity to rotational speed makes it possible to transport the welded material around the pin several times and to produce a joint of good quality.

  10. Finite-element 3D simulation tools for high-current relativistic electron beams

    Science.gov (United States)

    Humphries, Stanley; Ekdahl, Carl

    2002-08-01

    The DARHT second-axis injector is a challenge for computer simulations. Electrons are subject to strong beam-generated forces. The fields are fully three-dimensional and accurate calculations at surfaces are critical. We describe methods applied in OmniTrak, a 3D finite-element code suite that can address DARHT and the full range of charged-particle devices. The system handles mesh generation, electrostatics, magnetostatics and self-consistent particle orbits. The MetaMesh program generates meshes of conformal hexahedrons to fit any user geometry. The code has the unique ability to create structured conformal meshes with cubic logic. Organized meshes offer advantages in speed and memory utilization in the orbit and field solutions. OmniTrak is a versatile charged-particle code that handles 3D electric and magnetic field solutions on independent meshes. The program can update both 3D field solutions from the calculated beam space-charge and current-density. We shall describe numerical methods for orbit tracking on a hexahedron mesh. Topics include: 1) identification of elements along the particle trajectory, 2) fast searches and adaptive field calculations, 3) interpolation methods to terminate orbits on material surfaces, 4) automatic particle generation on multiple emission surfaces to model space-charge-limited emission and field emission, 5) flexible Child law algorithms, 6) implementation of the dual potential model for 3D magnetostatics, and 7) assignment of charge and current from model particle orbits for self-consistent fields.

  11. Development of a 3D consistent 1D neutronics model for reactor core simulation

    International Nuclear Information System (INIS)

    Lee, Ki Bog; Joo, Han Gyu; Cho, Byung Oh; Zee, Sung Quun

    2001-02-01

    In this report a 3D consistent 1D model based on nonlinear analytic nodal method is developed to reproduce the 3D results. During the derivation, the current conservation factor (CCF) is introduced which guarantees the same axial neutron currents obtained from the 1D equation as the 3D reference values. Furthermore in order to properly use 1D group constants, a new 1D group constants representation scheme employing tables for the fuel temperature, moderator density and boron concentration is developed and functionalized for the control rod tip position. To test the 1D kinetics model with CCF, several steady state and transient calculations were performed and compared with 3D reference values. The errors of K-eff values were reduced about one tenth when using CCF without significant computational overhead. And the errors of power distribution were decreased to the range of one fifth or tenth at steady state calculation. The 1D kinetics model with CCF and the 1D group constant functionalization employing tables as a function of control rod tip position can provide preciser results at the steady state and transient calculation. Thus it is expected that the 1D kinetics model derived in this report can be used in the safety analysis, reactor real time simulation coupled with system analysis code, operator support system etc.

  12. An inexpensive underwater mine countermeasures simulator with real-time 3D after action review

    Directory of Open Access Journals (Sweden)

    Robert Stone

    2016-10-01

    Full Text Available This paper presents the results of a concept capability demonstration pilot study, the aim of which was to investigate how inexpensive gaming software and hardware technologies could be exploited in the development and evaluation of a simulator prototype for training Royal Navy mine clearance divers, specifically focusing on the detection and accurate reporting of the location and condition of underwater ordnance. The simulator was constructed using the Blender open source 3D modelling toolkit and game engine, and featured not only an interactive 3D editor for underwater scenario generation by instructors, but also a real-time, 3D After Action Review (AAR system for formative assessment and feedback. The simulated scenarios and AAR architecture were based on early human factors observations and briefings conducted at the UK's Defence Diving School (DDS, an organisation that provides basic military diving training for all Royal Navy and Army (Royal Engineers divers. An experimental pilot study was undertaken to determine whether or not basic navigational and mine detection components of diver performance could be improved as a result of exposing participants to the AAR system, delivered between simulated diving scenarios. The results suggest that the provision of AAR was accompanied by significant performance improvements in the positive identification of simulated underwater ordnance (in contrast to non-ordnance objects and on participants' description of their location, their immediate in-water or seabed context and their structural condition. Only marginal improvements were found with participants' navigational performance in terms of their deviation accuracies from a pre-programmed expert search path. Overall, this project contributes to the growing corpus of evidence supporting the development of simulators that demonstrate the value of exploiting open source gaming software and the significance of adopting established games design

  13. Random telegraph signal amplitudes in sub 100 nm (decanano) MOSFETs: a 3D `Atomistic' simulation study

    OpenAIRE

    Asenov, A.; Balasubramaniam, R.; Brown, A.R.; Davies, J.H.; Saini, S.

    2000-01-01

    In this paper we use 3D simulations to study the amplitudes of random telegraph signals (RTS) associated with the trapping of a single carrier in interface states in the channel of sub 100 nm (decanano) MOSFETs. Both simulations using continuous doping charge and random discrete dopants in the active region of the MOSFETs are presented. We have studied the dependence of the RTS amplitudes on the position of the trapped charge in the channel and on the device design parameters. We have observe...

  14. Implementation of Headtracking and 3D Stereo with Unity and VRPN for Computer Simulations

    Science.gov (United States)

    Noyes, Matthew A.

    2013-01-01

    This paper explores low-cost hardware and software methods to provide depth cues traditionally absent in monocular displays. The use of a VRPN server in conjunction with a Microsoft Kinect and/or Nintendo Wiimote to provide head tracking information to a Unity application, and NVIDIA 3D Vision for retinal disparity support, is discussed. Methods are suggested to implement this technology with NASA's EDGE simulation graphics package, along with potential caveats. Finally, future applications of this technology to astronaut crew training, particularly when combined with an omnidirectional treadmill for virtual locomotion and NASA's ARGOS system for reduced gravity simulation, are discussed.

  15. Direct numerical simulation of 3D particle motion in an evaporating liquid film

    International Nuclear Information System (INIS)

    Hwang, Ho Chan; Son, Gi Hun

    2016-01-01

    A direct numerical simulation method is developed for 3D particle motion in liquid film evaporation. The liquid-gas and fluid-solid interfaces are tracked by a sharp-interface Level-set (LS) method, which includes the effects of evaporation, contact line and solid particles. The LS method is validated through simulation of the interaction between two particles falling in a single-phase fluid. The LS based DNS method is applied to computation of the particle motion in liquid film evaporation to investigate the particle-interface and particle-particle interactions

  16. Geant4 simulation of a 3D high resolution gamma camera

    International Nuclear Information System (INIS)

    Akhdar, H.; Kezzar, K.; Aksouh, F.; Assemi, N.; AlGhamdi, S.; AlGarawi, M.; Gerl, J.

    2015-01-01

    The aim of this work is to develop a 3D gamma camera with high position resolution and sensitivity relying on both distance/absorption and Compton scattering techniques and without using any passive collimation. The proposed gamma camera is simulated in order to predict its performance using the full benefit of Geant4 features that allow the construction of the needed geometry of the detectors, have full control of the incident gamma particles and study the response of the detector in order to test the suggested geometries. Three different geometries are simulated and each configuration is tested with three different scintillation materials (LaBr3, LYSO and CeBr3)

  17. CTF/DYN3D multi-scale coupled simulation of a rod ejection transient on the NURESIM platform

    Directory of Open Access Journals (Sweden)

    Yann Périn

    2017-09-01

    Full Text Available In the framework of the EU funded project NURESAFE, the subchannel code CTF and the neutronics code DYN3D were integrated and coupled on the NURESIM platform. The developments achieved during this 3-year project include assembly-level and pin-by-pin multiphysics thermal hydraulics/neutron kinetics coupling. In order to test this coupling, a PWR rod ejection transient was simulated on a MOX/UOX minicore. The transient is simulated using two different models of the minicore. In the first simulation, both codes model the core with an assembly-wise resolution. In the second simulation, a pin-by-pin fuel-centered model is used in CTF for the central assembly, and a pin power reconstruction method is applied in DYN3D. The analysis shows the influence of the different models on global parameters, such as the power and the average fuel temperature, but also on local parameters such as the maximum fuel temperature.

  18. A parallel code named NEPTUNE for 3D fully electromagnetic and pic simulations

    International Nuclear Information System (INIS)

    Dong Ye; Yang Wenyuan; Chen Jun; Zhao Qiang; Xia Fang; Ma Yan; Xiao Li; Sun Huifang; Chen Hong; Zhou Haijing; Mao Zeyao; Dong Zhiwei

    2010-01-01

    A parallel code named NEPTUNE for 3D fully electromagnetic and particle-in-cell (PIC) simulations is introduced, which could run on the Linux system with hundreds to thousand CPUs. NEPTUNE is suitable to simulate entire 3D HPM devices; many HPM devices are simulated and designed by using it. In NEPTUNE code, the electromagnetic fields are updated by using the finite-difference in time domain (FDTD) method of solving Maxwell equations and the particles are moved by using Buneman-Boris advance method of solving relativistic Newton-Lorentz equation. Electromagnetic fields and particles are coupled by using liner weighing interpolation PIC method, and the electric filed components are corrected by using Boris method of solve Poisson equation in order to ensure charge-conservation. NEPTUNE code could construct many complicated geometric structures, such as arbitrary axial-symmetric structures, plane transforming structures, slow-wave-structures, coupling holes, foils, and so on. The boundary conditions used in NEPTUNE code are introduced in brief, including perfectly electric conductor boundary, external wave boundary, and particle boundary. Finally, some typical HPM devices are simulated and test by using NEPTUNE code, including MILO, RBWO, VCO, and RKA. The simulation results are with correct and credible physical images, and the parallel efficiencies are also given. (authors)

  19. Multi-material 3D Models for Temporal Bone Surgical Simulation.

    Science.gov (United States)

    Rose, Austin S; Kimbell, Julia S; Webster, Caroline E; Harrysson, Ola L A; Formeister, Eric J; Buchman, Craig A

    2015-07-01

    A simulated, multicolor, multi-material temporal bone model can be created using 3-dimensional (3D) printing that will prove both safe and beneficial in training for actual temporal bone surgical cases. As the process of additive manufacturing, or 3D printing, has become more practical and affordable, a number of applications for the technology in the field of Otolaryngology-Head and Neck Surgery have been considered. One area of promise is temporal bone surgical simulation. Three-dimensional representations of human temporal bones were created from temporal bone computed tomography (CT) scans using biomedical image processing software. Multi-material models were then printed and dissected in a temporal bone laboratory by attending and resident otolaryngologists. A 5-point Likert scale was used to grade the models for their anatomical accuracy and suitability as a simulation of cadaveric and operative temporal bone drilling. The models produced for this study demonstrate significant anatomic detail and a likeness to human cadaver specimens for drilling and dissection. Simulated temporal bones created by this process have potential benefit in surgical training, preoperative simulation for challenging otologic cases, and the standardized testing of temporal bone surgical skills. © The Author(s) 2015.

  20. 3D printing of microtube in solid phantom to simulate tissue oxygenation and perfusion (Conference Presentation)

    Science.gov (United States)

    Lv, Xiang; Xue, Yue; Wang, Haili; Shen, Shu Wei; Zhou, Ximing; Liu, Guangli; Dong, Erbao; Xu, Ronald X.

    2017-03-01

    Tissue-simulating phantoms with interior vascular network may facilitate traceable calibration and quantitative validation of many medical optical devices. However, a solid phantom that reliably simulates tissue oxygenation and blood perfusion is still not available. This paper presents a new method to fabricate hollow microtubes for blood vessel simulation in solid phantoms. The fabrication process combines ultraviolet (UV) rapid prototyping technique with fluid mechanics of a coaxial jet flow. Polydimethylsiloxane (PDMS) and a UV-curable polymer are mixed at the designated ratio and extruded through a coaxial needle device to produce a coaxial jet flow. The extruded jet flow is quickly photo-polymerized by ultraviolet (UV) light to form vessel-simulating solid structures at different sizes ranging from 700 μm to 1000 μm. Microtube structures with adequate mechanical properties can be fabricated by adjusting material compositions and illumination intensity. Curved, straight and stretched microtubes can be formed by adjusting the extrusion speed of the materials and the speed of the 3D printing platform. To simulate vascular structures in biologic tissue, we embed vessel-simulating microtubes in a gel wax phantom of 10 cm x10 cm x 5 cm at the depth from 1 to 2 mm. Bloods at different oxygenation and hemoglobin concentration levels are circulated through the microtubes at different flow rates in order to simulate different oxygenation and perfusion conditions. The simulated physiologic parameters are detected by a tissue oximeter and a laser speckle blood flow meter respectively and compared with the actual values. Our experiments demonstrate that the proposed 3D printing process is able to produce solid phantoms with simulated vascular networks for potential applications in medical device calibration and drug delivery studies.

  1. A practical 3D printed simulator for endoscopic endonasal transsphenoidal surgery to improve basic operational skills.

    Science.gov (United States)

    Wen, Guodao; Cong, ZiXiang; Liu, KaiDong; Tang, Chao; Zhong, Chunyu; Li, Liwen; Dai, XuJie; Ma, Chiyuan

    2016-06-01

    We aimed to present a practical three-dimensional (3D) printed simulator to comprehensively and effectively accelerate the learning curve of endoscopic endonasal transsphenoidal surgery (EETS). The 3D printed simulator consists of three parts: (1) skull frame, (2) the nasal passage and the nasal alar of the face, and (3) a modified sella turcica. We aimed to improve three basic operational skills of surgeons: drilling, curetting, and aspirating. Eighteen neurosurgeons and five post-graduates were recruited and consented for the training. For trainees, (1) as the training progressed, the scores increased gradually, (2) a significant increase in the average scores was observed in the tenth training compared to the first training, and (3) there is a significant decrease in trainee variability in the shortening of the gap. The 18 neurosurgeons were divided into three groups: experts, assistants, and observers. For all three basic operations, (1) the average score of experts was obviously higher than that of the assistants, observers, and trainees' tenth training and (2) the average scores of assistants and observers were obviously higher than that of trainees' first training. A significant high in the average score between the assistants and the observers was seen for aspirating, but not for drilling or curetting. For curetting and aspirating, the tenth training average score of trainees was obviously higher than that of assistants and observers. This 3D printed simulator allows different endoscopic basic operations to be simulated and improves the EETS techniques of surgeons. We believed it to be a practical, simple, and low-cost simulator.

  2. Simulations of Aperture Synthesis Imaging Radar for the EISCAT_3D Project

    Science.gov (United States)

    La Hoz, C.; Belyey, V.

    2012-12-01

    EISCAT_3D is a project to build the next generation of incoherent scatter radars endowed with multiple 3-dimensional capabilities that will replace the current EISCAT radars in Northern Scandinavia. Aperture Synthesis Imaging Radar (ASIR) is one of the technologies adopted by the EISCAT_3D project to endow it with imaging capabilities in 3-dimensions that includes sub-beam resolution. Complemented by pulse compression, it will provide 3-dimensional images of certain types of incoherent scatter radar targets resolved to about 100 metres at 100 km range, depending on the signal-to-noise ratio. This ability will open new research opportunities to map small structures associated with non-homogeneous, unstable processes such as aurora, summer and winter polar radar echoes (PMSE and PMWE), Natural Enhanced Ion Acoustic Lines (NEIALs), structures excited by HF ionospheric heating, meteors, space debris, and others. To demonstrate the feasibility of the antenna configurations and the imaging inversion algorithms a simulation of synthetic incoherent scattering data has been performed. The simulation algorithm incorporates the ability to control the background plasma parameters with non-homogeneous, non-stationary components over an extended 3-dimensional space. Control over the positions of a number of separated receiving antennas, their signal-to-noise-ratios and arriving phases allows realistic simulation of a multi-baseline interferometric imaging radar system. The resulting simulated data is fed into various inversion algorithms. This simulation package is a powerful tool to evaluate various antenna configurations and inversion algorithms. Results applied to realistic design alternatives of EISCAT_3D will be described.

  3. Feasibility of the integration of CRONOS, a 3-D neutronics code, into real-time simulators

    International Nuclear Information System (INIS)

    Ragusa, J.C.

    2001-01-01

    In its effort to contribute to nuclear power plant safety, CEA proposes the integration of an engineering grade 3-D neutronics code into a real-time plant analyser. This paper describes the capabilities of the neutronics code CRONOS to achieve a fast running performance. First, we will present current core models in simulators and explain their drawbacks. Secondly, the mean features of CRONOS's spatial-kinetics methods will be reviewed. We will then present an optimum core representation with respect to mesh size, choice of finite elements (FE) basis and execution time, for accurate results as well as the multi 1-D thermal-hydraulics (T/H) model developed to take into account 3-D effects in updating the cross-sections. A Main Steam Line Break (MSLB) End-of-Life (EOL) Hot-Zero-Power (HZP) accident will be used as an example, before we conclude with the perspectives of integrating CRONOS's 3-D core model into real-time simulators. (author)

  4. Feasibility of the integration of CRONOS, a 3-D neutronics code, into real-time simulators

    Energy Technology Data Exchange (ETDEWEB)

    Ragusa, J.C. [CEA Saclay, Dept. de Mecanique et de Technologie, 91 - Gif-sur-Yvette (France)

    2001-07-01

    In its effort to contribute to nuclear power plant safety, CEA proposes the integration of an engineering grade 3-D neutronics code into a real-time plant analyser. This paper describes the capabilities of the neutronics code CRONOS to achieve a fast running performance. First, we will present current core models in simulators and explain their drawbacks. Secondly, the mean features of CRONOS's spatial-kinetics methods will be reviewed. We will then present an optimum core representation with respect to mesh size, choice of finite elements (FE) basis and execution time, for accurate results as well as the multi 1-D thermal-hydraulics (T/H) model developed to take into account 3-D effects in updating the cross-sections. A Main Steam Line Break (MSLB) End-of-Life (EOL) Hot-Zero-Power (HZP) accident will be used as an example, before we conclude with the perspectives of integrating CRONOS's 3-D core model into real-time simulators. (author)

  5. Toward high-speed 3D nonlinear soft tissue deformation simulations using Abaqus software.

    Science.gov (United States)

    Idkaidek, Ashraf; Jasiuk, Iwona

    2015-12-01

    We aim to achieve a fast and accurate three-dimensional (3D) simulation of a porcine liver deformation under a surgical tool pressure using the commercial finite element software Abaqus. The liver geometry is obtained using magnetic resonance imaging, and a nonlinear constitutive law is employed to capture large deformations of the tissue. Effects of implicit versus explicit analysis schemes, element type, and mesh density on computation time are studied. We find that Abaqus explicit and implicit solvers are capable of simulating nonlinear soft tissue deformations accurately using first-order tetrahedral elements in a relatively short time by optimizing the element size. This study provides new insights and guidance on accurate and relatively fast nonlinear soft tissue simulations. Such simulations can provide force feedback during robotic surgery and allow visualization of tissue deformations for surgery planning and training of surgical residents.

  6. Hybrid Reactor Simulation and 3-D Information Display of BWR Out-of-Phase Oscillation

    International Nuclear Information System (INIS)

    Edwards, Robert; Huang, Zhengyu

    2001-01-01

    The real-time hybrid reactor simulation (HRS) capability of the Penn State TRIGA reactor has been expanded for boiling water reactor (BWR) out-of-phase behavior. During BWR out-of-phase oscillation half of the core can significantly oscillate out of phase with the other half, while the average power reported by the neutronic instrumentation may show a much lower amplitude for the oscillations. A description of the new HRS is given; three computers are employed to handle all the computations required, including real-time data processing and graph generation. BWR out-of-phase oscillation was successfully simulated. By adjusting the reactivity feedback gains from boiling channels to the TRIGA reactor and to the first harmonic mode power simulation, limit cycle can be generated with both reactor power and the simulated first harmonic power. A 3-D display of spatial power distributions of fundamental mode, first harmonic, and total powers over the reactor cross section is shown

  7. PEPT: An invaluable tool for 3-D particle tracking and CFD simulation verification in hydrocyclone studies

    Directory of Open Access Journals (Sweden)

    Hoffmann Alex C.

    2013-05-01

    Full Text Available Particle tracks in a hydrocyclone generated both experimentally by positron emission particle tracking (PEPT and numerically with Eulerian-Lagranian CFD have been studied and compared. A hydrocyclone with a cylinder-on-cone design was used in this study, the geometries used in the CFD simulations and in the experiments being identical. It is shown that it is possible to track a fast-moving particle in a hydrocyclone using PEPT with high temporal and spatial resolutions. The numerical 3-D particle trajectories were generated using the Large Eddy Simulation (LES turbulence model for the fluid and Lagrangian particle tracking for the particles. The behaviors of the particles were analyzed in detail and were found to be consistent between experiments and CFD simulations. The tracks of the particles are discussed and related to the fluid flow field visualized in the CFD simulations using the cross-sectional static pressure distribution.

  8. HEXBU-3D, a three-dimensional PWR-simulator program for hexagonal fuel assemblies

    International Nuclear Information System (INIS)

    Karvinen, E.

    1981-06-01

    HEXBU-3D is a three-dimensional nodal simulator program for PWR reactors. It is designed for a reactor core that consists of hexagonal fuel assemblies and of big follower-type control assemblies. The program solves two-group diffusion equations in homogenized fuel assembly geometry by a sophisticated nodal method. The treatment of feedback effects from xenon-poisoning, fuel temperature, moderator temperature and density and soluble boron concentration are included in the program. The nodal equations are solved by a fast two-level iteration technique and the eigenvalue can be either the effective multiplication factor or the boron concentration of the moderator. Burnup calculations are performed by tabulated sets of burnup-dependent cross sections evaluated by a cell burnup program. HEXBY-3D has been originally programmed in FORTRAN V for the UNIVAC 1108 computer, but there is also another version which is operable on the CDC CYBER 170 computer. (author)

  9. Application of FUN3D Solver for Aeroacoustics Simulation of a Nose Landing Gear Configuration

    Science.gov (United States)

    Vatsa, Veer N.; Lockard, David P.; Khorrami, Mehdi R.

    2011-01-01

    Numerical simulations have been performed for a nose landing gear configuration corresponding to the experimental tests conducted in the Basic Aerodynamic Research Tunnel at NASA Langley Research Center. A widely used unstructured grid code, FUN3D, is examined for solving the unsteady flow field associated with this configuration. A series of successively finer unstructured grids has been generated to assess the effect of grid refinement. Solutions have been obtained on purely tetrahedral grids as well as mixed element grids using hybrid RANS/LES turbulence models. The agreement of FUN3D solutions with experimental data on the same size mesh is better on mixed element grids compared to pure tetrahedral grids, and in general improves with grid refinement.

  10. An innovative 3-D numerical modelling procedure for simulating repository-scale excavations in rock - SAFETI

    Energy Technology Data Exchange (ETDEWEB)

    Young, R. P.; Collins, D.; Hazzard, J.; Heath, A. [Department of Earth Sciences, Liverpool University, 4 Brownlow street, UK-0 L69 3GP Liverpool (United Kingdom); Pettitt, W.; Baker, C. [Applied Seismology Consultants LTD, 10 Belmont, Shropshire, UK-S41 ITE Shrewsbury (United Kingdom); Billaux, D.; Cundall, P.; Potyondy, D.; Dedecker, F. [Itasca Consultants S.A., Centre Scientifique A. Moiroux, 64, chemin des Mouilles, F69130 Ecully (France); Svemar, C. [Svensk Karnbranslemantering AB, SKB, Aspo Hard Rock Laboratory, PL 300, S-57295 Figeholm (Sweden); Lebon, P. [ANDRA, Parc de la Croix Blanche, 7, rue Jean Monnet, F-92298 Chatenay-Malabry (France)

    2004-07-01

    This paper presents current results from work performed within the European Commission project SAFETI. The main objective of SAFETI is to develop and test an innovative 3D numerical modelling procedure that will enable the 3-D simulation of nuclear waste repositories in rock. The modelling code is called AC/DC (Adaptive Continuum/ Dis-Continuum) and is partially based on Itasca Consulting Group's Particle Flow Code (PFC). Results are presented from the laboratory validation study where algorithms and procedures have been developed and tested to allow accurate 'Models for Rock' to be produced. Preliminary results are also presented on the use of AC/DC with parallel processors and adaptive logic. During the final year of the project a detailed model of the Prototype Repository Experiment at SKB's Hard Rock Laboratory will be produced using up to 128 processors on the parallel super computing facility at Liverpool University. (authors)

  11. The current status of the development of the technology on 3D computer simulation in Japan

    International Nuclear Information System (INIS)

    Kim, Hee Reyoung; Park, Seung Kook; Chung, Un Soo; Jung, Ki Jung

    2002-05-01

    The development background and property of the COSIDA, which is the 3D computer simulation system for the analysis on the dismantling procedure of the nuclear facilities in Japan was reviewed. The function of the visualization on the work area, Kinematics analysis and dismantling scenario analysis, which are the sub systems of the COSIDA, has been investigated. The physical, geometrical and radiological properties were modelled in 2D or 3D in the sub system of the visualization of the work area. In the sub system of the kinematics analysis, the command set on the basic work procedure for the control of the motion of the models at a cyber space was driven. The suitability of the command set was estimated by the application of COSIDA to the programming on the motion of the remote dismantling tools for dismantling the components of the nuclear facilities at cyber space

  12. In-cloud oxalate formation in the global troposphere: a 3-D modeling study

    Directory of Open Access Journals (Sweden)

    S. Myriokefalitakis

    2011-06-01

    Full Text Available Organic acids attract increasing attention as contributors to atmospheric acidity, secondary organic aerosol mass and aerosol hygroscopicity. Oxalic acid is globally the most abundant dicarboxylic acid, formed via chemical oxidation of gas-phase precursors in the aqueous phase of aerosols and droplets. Its lifecycle and atmospheric global distribution remain highly uncertain and are the focus of this study. The first global spatial and temporal distribution of oxalate, simulated using a state-of-the-art aqueous-phase chemical scheme embedded within the global 3-dimensional chemistry/transport model TM4-ECPL, is here presented. The model accounts for comprehensive gas-phase chemistry and its coupling with major aerosol constituents (including secondary organic aerosol. Model results are consistent with ambient observations of oxalate at rural and remote locations (slope = 1.16 ± 0.14, r2 = 0.36, N = 114 and suggest that aqueous-phase chemistry contributes significantly to the global atmospheric burden of secondary organic aerosol. In TM4-ECPL most oxalate is formed in-cloud and less than 5 % is produced in aerosol water. About 62 % of the oxalate is removed via wet deposition, 30 % by in-cloud reaction with hydroxyl radical, 4 % by in-cloud reaction with nitrate radical and 4 % by dry deposition. The in-cloud global oxalate net chemical production is calculated to be about 21–37 Tg yr−1 with almost 79 % originating from biogenic hydrocarbons, mainly isoprene. This condensed phase net source of oxalate in conjunction with a global mean turnover time against deposition of about 5 days, maintain oxalate's global tropospheric burden of 0.2–0.3 Tg, i.e. 0.05–0.1 Tg-C that is about 5–9 % of model-calculated water soluble organic carbon burden.

  13. Global fully kinetic models of planetary magnetospheres with iPic3D

    Science.gov (United States)

    Gonzalez, D.; Sanna, L.; Amaya, J.; Zitz, A.; Lembege, B.; Markidis, S.; Schriver, D.; Walker, R. J.; Berchem, J.; Peng, I. B.; Travnicek, P. M.; Lapenta, G.

    2016-12-01

    We report on the latest developments of our approach to model planetary magnetospheres, mini magnetospheres and the Earth's magnetosphere with the fully kinetic, electromagnetic particle in cell code iPic3D. The code treats electrons and multiple species of ions as full kinetic particles. We review: 1) Why a fully kinetic model and in particular why kinetic electrons are needed for capturing some of the most important aspects of the physics processes of planetary magnetospheres. 2) Why the energy conserving implicit method (ECIM) in its newest implementation [1] is the right approach to reach this goal. We consider the different electron scales and study how the new IECIM can be tuned to resolve only the electron scales of interest while averaging over the unresolved scales preserving their contribution to the evolution. 3) How with modern computing planetary magnetospheres, mini magnetosphere and eventually Earth's magnetosphere can be modeled with fully kinetic electrons. The path from petascale to exascale for iPiC3D is outlined based on the DEEP-ER project [2], using dynamic allocation of different processor architectures (Xeon and Xeon Phi) and innovative I/O technologies.Specifically results from models of Mercury are presented and compared with MESSENGER observations and with previous hybrid (fluid electrons and kinetic ions) simulations. The plasma convection around the planets includes the development of hydrodynamic instabilities at the flanks, the presence of the collisionless shocks, the magnetosheath, the magnetopause, reconnection zones, the formation of the plasma sheet and the magnetotail, and the variation of ion/electron plasma flows when crossing these frontiers. Given the full kinetic nature of our approach we focus on detailed particle dynamics and distribution at locations that can be used for comparison with satellite data. [1] Lapenta, G. (2016). Exactly Energy Conserving Implicit Moment Particle in Cell Formulation. arXiv preprint ar

  14. Nonlinear plasma wave models in 3D fluid simulations of laser-plasma interaction

    Science.gov (United States)

    Chapman, Thomas; Berger, Richard; Arrighi, Bill; Langer, Steve; Banks, Jeffrey; Brunner, Stephan

    2017-10-01

    Simulations of laser-plasma interaction (LPI) in inertial confinement fusion (ICF) conditions require multi-mm spatial scales due to the typical laser beam size and durations of order 100 ps in order for numerical laser reflectivities to converge. To be computationally achievable, these scales necessitate a fluid-like treatment of light and plasma waves with a spatial grid size on the order of the light wave length. Plasma waves experience many nonlinear phenomena not naturally described by a fluid treatment, such as frequency shifts induced by trapping, a nonlinear (typically suppressed) Landau damping, and mode couplings leading to instabilities that can cause the plasma wave to decay rapidly. These processes affect the onset and saturation of stimulated Raman and Brillouin scattering, and are of direct interest to the modeling and prediction of deleterious LPI in ICF. It is not currently computationally feasible to simulate these Debye length-scale phenomena in 3D across experimental scales. Analytically-derived and/or numerically benchmarked models of processes occurring at scales finer than the fluid simulation grid offer a path forward. We demonstrate the impact of a range of kinetic processes on plasma reflectivity via models included in the LPI simulation code pF3D. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  15. Water flow prediction for Membranes using 3D simulations with detailed morphology

    KAUST Repository

    Shi, Meixia

    2015-04-01

    The membrane morphology significantly influences membrane performance. For osmotically driven membrane processes, the morphology strongly affects the internal concentration polarization. Different membrane morphologies were generated by simulation and their influence on membrane performance was studied, using a 3D model. The simulation results were experimentally validated for two classical phase-inversion membrane morphologies: sponge- and finger-like structures. Membrane porosity and scanning electron microscopy image information were used as model input. The permeance results from the simulation fit well the experimentally measured permeances. Water permeances were predicted for different kinds of finger-like cavity membranes with different finger-like cavity lengths and various finger-like cavity sets, as well as for membranes with cylindrical cavities. The results provide realistic information on how to increase water permeance, and also illustrate that membrane’s complete morphology is important for the accurate water permeance evaluation. Evaluations only based on porosity might be misleading, and the new 3D simulation approach gives a more realistic representation.

  16. Novel 3D/VR interactive environment for MD simulations, visualization and analysis.

    Science.gov (United States)

    Doblack, Benjamin N; Allis, Tim; Dávila, Lilian P

    2014-12-18

    The increasing development of computing (hardware and software) in the last decades has impacted scientific research in many fields including materials science, biology, chemistry and physics among many others. A new computational system for the accurate and fast simulation and 3D/VR visualization of nanostructures is presented here, using the open-source molecular dynamics (MD) computer program LAMMPS. This alternative computational method uses modern graphics processors, NVIDIA CUDA technology and specialized scientific codes to overcome processing speed barriers common to traditional computing methods. In conjunction with a virtual reality system used to model materials, this enhancement allows the addition of accelerated MD simulation capability. The motivation is to provide a novel research environment which simultaneously allows visualization, simulation, modeling and analysis. The research goal is to investigate the structure and properties of inorganic nanostructures (e.g., silica glass nanosprings) under different conditions using this innovative computational system. The work presented outlines a description of the 3D/VR Visualization System and basic components, an overview of important considerations such as the physical environment, details on the setup and use of the novel system, a general procedure for the accelerated MD enhancement, technical information, and relevant remarks. The impact of this work is the creation of a unique computational system combining nanoscale materials simulation, visualization and interactivity in a virtual environment, which is both a research and teaching instrument at UC Merced.

  17. Water flow prediction for Membranes using 3D simulations with detailed morphology

    KAUST Repository

    Shi, Meixia; Printsypar, Galina; Iliev, Oleg; Calo, Victor M.; Amy, Gary L.; Nunes, Suzana Pereira

    2015-01-01

    The membrane morphology significantly influences membrane performance. For osmotically driven membrane processes, the morphology strongly affects the internal concentration polarization. Different membrane morphologies were generated by simulation and their influence on membrane performance was studied, using a 3D model. The simulation results were experimentally validated for two classical phase-inversion membrane morphologies: sponge- and finger-like structures. Membrane porosity and scanning electron microscopy image information were used as model input. The permeance results from the simulation fit well the experimentally measured permeances. Water permeances were predicted for different kinds of finger-like cavity membranes with different finger-like cavity lengths and various finger-like cavity sets, as well as for membranes with cylindrical cavities. The results provide realistic information on how to increase water permeance, and also illustrate that membrane’s complete morphology is important for the accurate water permeance evaluation. Evaluations only based on porosity might be misleading, and the new 3D simulation approach gives a more realistic representation.

  18. A hand-held 3D laser scanning with global positioning system of subvoxel precision

    International Nuclear Information System (INIS)

    Arias, Nestor; Meneses, Nestor; Meneses, Jaime; Gharbi, Tijani

    2011-01-01

    In this paper we propose a hand-held 3D laser scanner composed of an optical head device to extract 3D local surface information and a stereo vision system with subvoxel precision to measure the position and orientation of the 3D optical head. The optical head is manually scanned over the surface object by the operator. The orientation and position of the 3D optical head is determined by a phase-sensitive method using a 2D regular intensity pattern. This phase reference pattern is rigidly fixed to the optical head and allows their 3D location with subvoxel precision in the observation field of the stereo vision system. The 3D resolution achieved by the stereo vision system is about 33 microns at 1.8 m with an observation field of 60cm x 60cm.

  19. Computer Simulation of Robotic Device Components in 3D Printer Manufacturing

    Directory of Open Access Journals (Sweden)

    M. A. Kiselev

    2016-01-01

    Full Text Available The paper considers a relevant problem "Computer simulation of robotic device components in manufacturing on a 3D printer" and highlights the problem of computer simulation based on the cognitive programming technology of robotic device components. The paper subject is urgent because computer simulation of force-torque and accuracy characteristics of robot components in terms of their manufacturing properties and conditions from polymeric and metallic materials is of paramount importance for programming and manufacturing on the 3D printers. Two types of additive manufacturing technologies were used:1. FDM (Fused deposition modeling - layered growth of products from molten plastic strands;2. SLM (Selective laser melting - selective laser sintering of metal powders, which, in turn, create:• conditions for reducing the use of expensive equipment;• reducing weight and increasing strength through optimization of  the lattice structures when using a bionic design;• a capability to implement mathematical modeling of individual components of robotic and other devices in terms of appropriate characteristics;• a 3D printing capability to create unique items, which cannot be made by other known methods.The paper aim was to confirm the possibility of ensuring the strength and accuracy characteristics of cases when printing from polymeric and metallic materials on a 3D printer. The investigation emphasis is on mathematical modeling based on the cognitive programming technology using the additive technologies in their studies since it is, generally, impossible to make the obtained optimized structures on the modern CNC machines.The latter allows us to create a program code to be clear to other developers without cost, additional time for development, adaptation and implementation.Year by year Russian companies increasingly use a 3D-print system in mechanical engineering, aerospace industry, and for scientific purposes. Machines for the additive

  20. 3D numerical simulations of negative hydrogen ion extraction using realistic plasma parameters, geometry of the extraction aperture and full 3D magnetic field map

    Science.gov (United States)

    Mochalskyy, S.; Wünderlich, D.; Ruf, B.; Franzen, P.; Fantz, U.; Minea, T.

    2014-02-01

    Decreasing the co-extracted electron current while simultaneously keeping negative ion (NI) current sufficiently high is a crucial issue on the development plasma source system for ITER Neutral Beam Injector. To support finding the best extraction conditions the 3D Particle-in-Cell Monte Carlo Collision electrostatic code ONIX (Orsay Negative Ion eXtraction) has been developed. Close collaboration with experiments and other numerical models allows performing realistic simulations with relevant input parameters: plasma properties, geometry of the extraction aperture, full 3D magnetic field map, etc. For the first time ONIX has been benchmarked with commercial positive ions tracing code KOBRA3D. A very good agreement in terms of the meniscus position and depth has been found. Simulation of NI extraction with different e/NI ratio in bulk plasma shows high relevance of the direct negative ion extraction from the surface produced NI in order to obtain extracted NI current as in the experimental results from BATMAN testbed.

  1. A 3D TCAD simulation of a thermoelectric module configured for thermoelectric power generation, cooling and heating

    Science.gov (United States)

    Gould, C. A.; Shammas, N. Y. A.; Grainger, S.; Taylor, I.; Simpson, K.

    2012-06-01

    This paper documents the 3D modeling and simulation of a three couple thermoelectric module using the Synopsys Technology Computer Aided Design (TCAD) semiconductor simulation software. Simulation results are presented for thermoelectric power generation, cooling and heating, and successfully demonstrate the basic thermoelectric principles. The 3D TCAD simulation model of a three couple thermoelectric module can be used in the future to evaluate different thermoelectric materials, device structures, and improve the efficiency and performance of thermoelectric modules.

  2. Numerical simulation of 3-D turbulent flow through entire stage in a multistage centrifugal pump

    International Nuclear Information System (INIS)

    Huang, S.; Islam, M.F.; Liu, P.

    2005-01-01

    A three-dimensional turbulent flow through a multistage centrifugal pump is numerically simulated using a commercial CFD software package. The simulation and analysis include flow fields in rotating impeller and stationary diffuser and is completed in a multiple reference frame. The standard k-ε turbulence model is applied. The analysis of the simulation reveals that the reverse flows exist in the zone near the impeller exit and diffuser entrance, resulting in flow field asymmetric and unsteady. There is a considerable interference on velocity field at impeller exit due to the interaction between impeller blades and diffuser vanes. The hydraulic performance is connected and evaluated with the 3-D computational flow field. The current computation is verified by comparing predicted and measured head. (author)

  3. hp-HGS strategy for inverse 3D DC resistivity logging measurement simulations

    KAUST Repository

    Gajda-Zaǵorska, Ewa

    2012-06-02

    In this paper we present a twin adaptive strategy hp-HGS for solving inverse problems related to 3D DC borehole resistivity measurement simulations. The term “simulation of measurements” is widely used by the geophysical community. A quantity of interest, voltage, is measured at a receiver electrode located in the logging instrument. We use the self-adaptive goal-oriented hp-Finite Element Method (hp-FEM) computer simulations of the process of measurements in deviated wells (when the angle between the borehole and formation layers are < 90 deg). We also employ the hierarchical genetic search (HGS) algorithm to solve the inverse problem. Each individual in the population represents a single configuration of the formation layers. The evaluation of the individual is performed by solving the direct problem by means of the hp-FEM algorithm and by comparison with measured logging curve. We conclude the paper with some discussion on the parallelization of the algorithm.

  4. Effect of Single-Electron Interface Trapping in Decanano MOSFETs: A 3D Atomistic Simulation Study

    Science.gov (United States)

    Asenov, Asen; Balasubramaniam, R.; Brown, A. R.; Davies, J. H.

    2000-01-01

    We study the effect of trapping/detrapping of a single-electron in interface states in the channel of n-type MOSFETs with decanano dimensions using 3D atomistic simulation techniques. In order to highlight the basic dependencies, the simulations are carried out initially assuming continuous doping charge, and discrete localized charge only for the trapped electron. The dependence of the random telegraph signal (RTS) amplitudes on the device dimensions and on the position of the trapped charge in the channel are studied in detail. Later, in full-scale, atomistic simulations assuming discrete charge for both randomly placed dopants and the trapped electron, we highlight the importance of current percolation and of traps with strategic position where the trapped electron blocks a dominant current path.

  5. hp-HGS strategy for inverse 3D DC resistivity logging measurement simulations

    KAUST Repository

    Gajda-Zaǵorska, Ewa; Paszý nski, Maciej; Schaefer, Robert; Pardo, David; Calo, Victor M.

    2012-01-01

    In this paper we present a twin adaptive strategy hp-HGS for solving inverse problems related to 3D DC borehole resistivity measurement simulations. The term “simulation of measurements” is widely used by the geophysical community. A quantity of interest, voltage, is measured at a receiver electrode located in the logging instrument. We use the self-adaptive goal-oriented hp-Finite Element Method (hp-FEM) computer simulations of the process of measurements in deviated wells (when the angle between the borehole and formation layers are < 90 deg). We also employ the hierarchical genetic search (HGS) algorithm to solve the inverse problem. Each individual in the population represents a single configuration of the formation layers. The evaluation of the individual is performed by solving the direct problem by means of the hp-FEM algorithm and by comparison with measured logging curve. We conclude the paper with some discussion on the parallelization of the algorithm.

  6. A 3D technique for simulation of irregular electron treatment fields using a digital camera

    International Nuclear Information System (INIS)

    Bassalow, Roustem; Sidhu, Narinder P.

    2003-01-01

    Cerrobend inserts, which define electron field apertures, are manufactured at our institution using perspex templates. Contours are reproduced manually on these templates at the simulator from the field outlines drawn on the skin or mask of a patient. A previously reported technique for simulation of electron treatment fields uses a digital camera to eliminate the need for such templates. However, avoidance of the image distortions introduced by non-flat surfaces on which the electron field outlines were drawn could only be achieved by limiting the application of this technique to surfaces which were flat or near flat. We present a technique that employs a digital camera and allows simulation of electron treatment fields contoured on an anatomical surface of an arbitrary three-dimensional (3D) shape, such as that of the neck, extremities, face, or breast. The procedure is fast, accurate, and easy to perform

  7. Simulating Growth Kinetics in a Data-Parallel 3D Lattice Photobioreactor

    Directory of Open Access Journals (Sweden)

    A. V. Husselmann

    2013-01-01

    Full Text Available Though there have been many attempts to address growth kinetics in algal photobioreactors, surprisingly little have attempted an agent-based modelling (ABM approach. ABM has been heralded as a method of practical scientific inquiry into systems of a complex nature and has been applied liberally in a range of disciplines including ecology, physics, social science, and microbiology with special emphasis on pathogenic bacterial growth. We bring together agent-based simulation with the Photosynthetic Factory (PSF model, as well as certain key bioreactor characteristics in a visual 3D, parallel computing fashion. Despite being at small scale, the simulation gives excellent visual cues on the dynamics of such a reactor, and we further investigate the model in a variety of ways. Our parallel implementation on graphical processing units of the simulation provides key advantages, which we also briefly discuss. We also provide some performance data, along with particular effort in visualisation, using volumetric and isosurface rendering.

  8. Fabrication of cerebral aneurysm simulator with a desktop 3D printer.

    Science.gov (United States)

    Liu, Yu; Gao, Qing; Du, Song; Chen, ZiChen; Fu, JianZhong; Chen, Bing; Liu, ZhenJie; He, Yong

    2017-05-17

    Now, more and more patients are suffering cerebral aneurysm. However, long training time limits the rapid growth of cerebrovascular neurosurgeons. Here we developed a novel cerebral aneurysm simulator which can be better represented the dynamic bulging process of cerebral aneurysm The proposed simulator features the integration of a hollow elastic vascular model, a skull model and a brain model, which can be affordably fabricated at the clinic (Fab@Clinic), under $25.00 each with the help of a low-cost desktop 3D printer. Moreover, the clinical blood flow and pulsation pressure similar to the human can be well simulated, which can be used to train the neurosurgical residents how to clip aneurysms more effectively.

  9. 3-D Spontaneous Rupture Simulations of the 2016 Kumamoto, Japan, Earthquake

    Science.gov (United States)

    Urata, Yumi; Yoshida, Keisuke; Fukuyama, Eiichi

    2017-04-01

    We investigated the M7.3 Kumamoto, Japan, earthquake to illuminate why and how the rupture of the main shock propagated successfully by 3-D dynamic rupture simulations, assuming a complicated fault geometry estimated based on the distributions of aftershocks. The M7.3 main shock occurred along the Futagawa and Hinagu faults. A few days before, three M6-class foreshocks occurred. Their hypocenters were located along by the Hinagu and Futagawa faults and their focal mechanisms were similar to those of the main shock; therefore, an extensive stress shadow can have been generated on the fault plane of the main shock. First, we estimated the geometry of the fault planes of the three foreshocks as well as that of the main shock based on the temporal evolution of relocated aftershock hypocenters. Then, we evaluated static stress changes on the main shock fault plane due to the occurrence of the three foreshocks assuming elliptical cracks with constant stress drops on the estimated fault planes. The obtained static stress change distribution indicated that the hypocenter of the main shock is located on the region with positive Coulomb failure stress change (ΔCFS) while ΔCFS in the shallow region above the hypocenter was negative. Therefore, these foreshocks could encourage the initiation of the main shock rupture and could hinder the rupture propagating toward the shallow region. Finally, we conducted 3-D dynamic rupture simulations of the main shock using the initial stress distribution, which was the sum of the static stress changes by these foreshocks and the regional stress field. Assuming a slip-weakening law with uniform friction parameters, we conducted 3-D dynamic rupture simulations by varying the friction parameters and the values of the principal stresses. We obtained feasible parameter ranges to reproduce the rupture propagation of the main shock consistent with those revealed by seismic waveform analyses. We also demonstrated that the free surface encouraged

  10. Use of computational simulation for evaluation of 3D printed phantoms for application in clinical dosimetry

    International Nuclear Information System (INIS)

    Valeriano, Caio César Santos

    2017-01-01

    The purpose of a phantom is to represent the change in the radiation field caused by absorption and scattering in a given tissue or organ of interest. Its geometrical characteristics and composition should be as close as possible to the values associated with its natural analogue. Anatomical structures can be transformed into 3D virtual objects by medical imaging techniques (e.g. Computed Tomography) and printed by rapid prototyping using materials, for example, polylactic acid. Its production for specific patients requires fulfilling requirements such as geometric accuracy with the individual's anatomy and tissue equivalence, so that usable measurements can be made, and be insensitive to the radiation effects. The objective of this work was to evaluate the behavior of 3D printed materials when exposed to different photon beams, with emphasis on the quality of radiotherapy (6 MV), aiming its application in clinical dosimetry. For this, 30 thermoluminescent dosimeters of LiF:Mg,Ti were used. The equivalence between the PMMA and the printed PLA for the thermoluminescent response of 30 dosimeters of CaSO 4 : Dy was also analyzed. The irradiations with radiotherapy photon beams were simulated using the Eclipse TM treatment planning system,with the Anisotropic Analytical Algorithm and the Acuros ® XB Advanced Dose Calculation algorithm. In addition to the use of Eclipse TM and dosimetric tests, computational simulations were realized using the MCNP5 code. Simulations with the MCNP5 code were performed to calculate the attenuation coefficient of printed plates exposed to different radiodiagnosis X-rays qualities and to develop a computational model of 3D printed plates. (author)

  11. 3D DIGITAL SIMULATION OF MINNAN TEMPLE ARCHITECTURE CAISSON'S CRAFT TECHNIQUES

    Directory of Open Access Journals (Sweden)

    Y. C. Lin

    2013-07-01

    Full Text Available Caisson is one of the important representations of the Minnan (southern Fujian temple architecture craft techniques and decorative aesthetics. The special component design and group building method present the architectural thinking and personal characteristics of great carpenters of Minnan temple architecture. In late Qing Dynasty, the appearance and style of caissons of famous temples in Taiwan apparently presented the building techniques of the great carpenters. However, as the years went by, the caisson design and craft techniques were not fully inherited, which has been a great loss of cultural assets. Accordingly, with the caisson of Fulong temple, a work by the well-known great carpenter in Tainan as an example, this study obtained the thinking principles of the original design and the design method at initial period of construction through interview records and the step of redrawing the "Tng-Ko" (traditional design, stakeout and construction tool. We obtained the 3D point cloud model of the caisson of Fulong temple using 3D laser scanning technology, and established the 3D digital model of each component of the caisson. Based on the caisson component procedure obtained from interview records, this study conducted the digital simulation of the caisson component to completely recode and present the caisson design, construction and completion procedure. This model of preserving the craft techniques for Minnan temple caisson by using digital technology makes specific contribution to the heritage of the craft techniques while providing an important reference for the digital preservation of human cultural assets.

  12. Recent Developments in the VISRAD 3-D Target Design and Radiation Simulation Code

    Science.gov (United States)

    Macfarlane, Joseph; Golovkin, Igor; Sebald, James

    2017-10-01

    The 3-D view factor code VISRAD is widely used in designing HEDP experiments at major laser and pulsed-power facilities, including NIF, OMEGA, OMEGA-EP, ORION, Z, and LMJ. It simulates target designs by generating a 3-D grid of surface elements, utilizing a variety of 3-D primitives and surface removal algorithms, and can be used to compute the radiation flux throughout the surface element grid by computing element-to-element view factors and solving power balance equations. Target set-up and beam pointing are facilitated by allowing users to specify positions and angular orientations using a variety of coordinates systems (e.g., that of any laser beam, target component, or diagnostic port). Analytic modeling for laser beam spatial profiles for OMEGA DPPs and NIF CPPs is used to compute laser intensity profiles throughout the grid of surface elements. VISRAD includes a variety of user-friendly graphics for setting up targets and displaying results, can readily display views from any point in space, and can be used to generate image sequences for animations. We will discuss recent improvements to conveniently assess beam capture on target and beam clearance of diagnostic components, as well as plans for future developments.

  13. A 3d particle simulation code for heavy ion fusion accelerator studies

    International Nuclear Information System (INIS)

    Friedman, A.; Bangerter, R.O.; Callahan, D.A.; Grote, D.P.; Langdon, A.B.; Haber, I.

    1990-01-01

    We describe WARP, a new particle-in-cell code being developed and optimized for ion beam studies in true geometry. We seek to model transport around bends, axial compression with strong focusing, multiple beamlet interaction, and other inherently 3d processes that affect emittance growth. Constraints imposed by memory and running time are severe. Thus, we employ only two 3d field arrays (ρ and φ), and difference φ directly on each particle to get E, rather than interpolating E from three meshes; use of a single 3d array is feasible. A new method for PIC simulation of bent beams follows the beam particles in a family of rotated laboratory frames, thus ''straightening'' the bends. We are also incorporating an envelope calculation, an (r, z) model, and 1d (axial) model within WARP. The BASIS development and run-time system is used, providing a powerful interactive environment in which the user has access to all variables in the code database. 10 refs., 3 figs

  14. RF study and 3-D simulations of a side-coupling thermionic RF-gun

    International Nuclear Information System (INIS)

    Rimjaem, S.; Kusoljariyakul, K.; Thongbai, C.

    2014-01-01

    A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012 © . RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance

  15. High-resolution 3D simulations of NIF ignition targets performed on Sequoia with HYDRA

    Science.gov (United States)

    Marinak, M. M.; Clark, D. S.; Jones, O. S.; Kerbel, G. D.; Sepke, S.; Patel, M. V.; Koning, J. M.; Schroeder, C. R.

    2015-11-01

    Developments in the multiphysics ICF code HYDRA enable it to perform large-scale simulations on the Sequoia machine at LLNL. With an aggregate computing power of 20 Petaflops, Sequoia offers an unprecedented capability to resolve the physical processes in NIF ignition targets for a more complete, consistent treatment of the sources of asymmetry. We describe modifications to HYDRA that enable it to scale to over one million processes on Sequoia. These include new options for replicating parts of the mesh over a subset of the processes, to avoid strong scaling limits. We consider results from a 3D full ignition capsule-only simulation performed using over one billion zones run on 262,000 processors which resolves surface perturbations through modes l = 200. We also report progress towards a high-resolution 3D integrated hohlraum simulation performed using 262,000 processors which resolves surface perturbations on the ignition capsule through modes l = 70. These aim for the most complete calculations yet of the interactions and overall impact of the various sources of asymmetry for NIF ignition targets. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

  16. RF study and 3-D simulations of a side-coupling thermionic RF-gun

    Energy Technology Data Exchange (ETDEWEB)

    Rimjaem, S., E-mail: sakhorn.rimjaem@cmu.ac.th [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400 (Thailand); Kusoljariyakul, K.; Thongbai, C. [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400 (Thailand)

    2014-02-01

    A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012{sup ©}. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

  17. RF study and 3-D simulations of a side-coupling thermionic RF-gun

    Science.gov (United States)

    Rimjaem, S.; Kusoljariyakul, K.; Thongbai, C.

    2014-02-01

    A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012©. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

  18. 3D Simulations for a Micron-Scale, Dielectric-Based Acceleration Experiment

    International Nuclear Information System (INIS)

    Yoder, R. B.; Travish, G.; Xu Jin; Rosenzweig, J. B.

    2009-01-01

    An experimental program to demonstrate a dielectric, slab-symmetric accelerator structure has been underway for the past two years. These resonant devices are driven by a side-coupled 800-nm laser and can be configured to maintain the field profile necessary for synchronous acceleration and focusing of relativistic or nonrelativistic particles. We present 3D simulations of various versions of the structure geometry, including a metal-walled structure relevant to ongoing cold tests on resonant properties, and an all-dielectric structure to be constructed for a proof-of-principle acceleration experiment.

  19. A General Arbitrary Lagrangian Eulerian Formulation for the Numerical Simulation of 3D Forming Processes

    International Nuclear Information System (INIS)

    Boman, R.; Papeleux, L.; Ponthot, J. P.

    2007-01-01

    In this paper, the Arbitrary Lagrangian Eulerian formalism is used to compute the steady state of a 2D metal cutting operation and a 3D U-shaped cold roll forming process. Compared to the Lagrangian case, this method allows the use of a refined mesh near the tools, leading to an accurate representation of the chip formation (metal cutting) and the bending of the sheet (roll forming) with a limited computational time. The main problem of this kind of simulation is the rezoning of the nodes on the free surfaces of the sheet. A modified iterative isoparametric smoother is used to manage this geometrically complex and CPU expensive task

  20. 3D simulation of an audible ultrasonic electrolarynx using difference waves.

    Science.gov (United States)

    Mills, Patrick; Zara, Jason

    2014-01-01

    A total laryngectomy removes the vocal folds which are fundamental in forming voiced sounds that make speech possible. Although implanted prosthetics are commonly used in developed countries, simple handheld vibrating electrolarynxes are still common worldwide. These devices are easy to use but suffer from many drawbacks including dedication of a hand, mechanical sounding voice, and sound leakage. To address some of these drawbacks, we introduce a novel electrolarynx that uses vibro-acoustic interference of dual ultrasonic waves to generate an audible fundamental frequency. A 3D simulation of the principles of the device is presented in this paper.

  1. 3D streamers simulation in a pin to plane configuration using massively parallel computing

    Science.gov (United States)

    Plewa, J.-M.; Eichwald, O.; Ducasse, O.; Dessante, P.; Jacobs, C.; Renon, N.; Yousfi, M.

    2018-03-01

    This paper concerns the 3D simulation of corona discharge using high performance computing (HPC) managed with the message passing interface (MPI) library. In the field of finite volume methods applied on non-adaptive mesh grids and in the case of a specific 3D dynamic benchmark test devoted to streamer studies, the great efficiency of the iterative R&B SOR and BiCGSTAB methods versus the direct MUMPS method was clearly demonstrated in solving the Poisson equation using HPC resources. The optimization of the parallelization and the resulting scalability was undertaken as a function of the HPC architecture for a number of mesh cells ranging from 8 to 512 million and a number of cores ranging from 20 to 1600. The R&B SOR method remains at least about four times faster than the BiCGSTAB method and requires significantly less memory for all tested situations. The R&B SOR method was then implemented in a 3D MPI parallelized code that solves the classical first order model of an atmospheric pressure corona discharge in air. The 3D code capabilities were tested by following the development of one, two and four coplanar streamers generated by initial plasma spots for 6 ns. The preliminary results obtained allowed us to follow in detail the formation of the tree structure of a corona discharge and the effects of the mutual interactions between the streamers in terms of streamer velocity, trajectory and diameter. The computing time for 64 million of mesh cells distributed over 1000 cores using the MPI procedures is about 30 min ns-1, regardless of the number of streamers.

  2. Insights from 3D numerical simulations on the dynamics of the India-Asia collision zone

    Science.gov (United States)

    Pusok, A. E.; Kaus, B.; Popov, A.

    2013-12-01

    The dynamics of the India-Asia collision zone remains one of the most remarkable topics of the current research interest: the transition from subduction to collision and uplift, followed by the rise of the abnormally thick Tibetan plateau, and the deformation at its Eastern and Western syntaxes, are processes still not fully understood. Models that have addressed this topic include wholescale underthrusting of Indian lithospheric mantle under Tibet, distributed homogeneous shortening or the thin-sheet model, slip-line field model for lateral extrusion or lower crustal flow models for the exhumation of the Himalayan units and lateral spreading of the Tibetan plateau. Of these, the thin-sheet model has successfully illustrated some of the basic physics of continental collision and has the advantage of a 3D model being reduced to 2D, but one of its major shortcomings is that it cannot simultaneously represent channel flow and gravitational collapse of the mantle lithosphere, since these mechanisms require the lithosphere to interact with the underlying mantle, or to have a vertically non-homogeneous rheology. As a consequence, 3D models are emerging as powerful tools to understand the dynamics of coupled systems. However, because of yet recent developments and various complexities, the current 3D models simulating the dynamics of continent collision zones have relied on certain explicit assumptions, such as replacing part of the asthenosphere with various types of boundary conditions that mimic the effect of mantle flow, in order to focus on the lithospheric/crustal deformation. Here, we employ the parallel 3D code LaMEM (Lithosphere and Mantle Evolution Model), with a finite difference staggered grid solver, which is capable of simulating lithospheric deformation while simultaneously taking mantle flow and a free surface into account. We present qualitative results on lithospheric and upper-mantle scale simulations in which the Indian lithosphere is subducted and

  3. 3D printing application and numerical simulations in a fracture system

    Science.gov (United States)

    Yoon, H.; Martinez, M. J.

    2017-12-01

    The hydrogeological and mechanical properties in fractured and porous media are fundamental to predicting coupled multiphysics processes in the subsurface. Recent advances in experimental methods and multi-scale imaging capabilities have revolutionized our ability to quantitatively characterize geomaterials and digital counterparts are now routinely used for numerical simulations to characterize petrophysical and mechanical properties across scales. 3D printing is a very effective and creative technique that reproduce the digital images in a controlled way. For geoscience applications, 3D printing can be co-opted to print reproducible porous and fractured structures derived from CT-imaging of actual rocks and theoretical algorithms for experimental testing. In this work we used a stereolithography (SLA) method to create a single fracture network. The fracture in shale was first scanned using a microCT system and then the digital fracture network was printed into two parts and assembled. Aperture ranges from 0.3 to 1 mm. In particular, we discuss the design of single fracture network and the progress of printing practices to reproduce the fracture network system. Printed samples at different scales are used to measure the permeability and surface roughness. Various numerical simulations including (non-)reactive transport and multiphase flow cases are performed to study fluid flow characterization. We will also discuss the innovative advancement of 3D printing techniques applicable for coupled processes in the subsurface. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.

  4. A Handy Preterm Infant Incubator for Providing Intensive Care: Simulation, 3D Printed Prototype, and Evaluation.

    Science.gov (United States)

    Zaylaa, Amira J; Rashid, Mohamad; Shaib, Mounir; El Majzoub, Imad

    2018-01-01

    Preterm infants encounter an abrupt delivery before their complete maturity during the third trimester of pregnancy. Polls anticipate an increase in the rates of preterm infants for 2025, especially in middle- and low-income countries. Despite the abundance of intensive care methods for preterm infants, such as, but not limited to, commercial, transport, embrace warmer, radiant warmer, and Kangaroo Mother Care methods, they are either expensive, lack the most essential requirements or specifications, or lack the maternal-preterm bond. This drove us to carry this original research and innovative idea of developing a new 3D printed prototype of a Handy preterm infant incubator. We aim to provide the most indispensable intensive care with the lowest cost, to bestow low-income countries with the Handy incubator's care, preserve the maternal -preterm's bond, and diminish the rate of mortality. Biomedical features, electronics, and biocompatible materials were utilized. The design was simulated, the prototype was 3D printed, and the outcomes were tested and evaluated. Simulation results showed the best fit for the Handy incubator's components. Experimental results showed the 3D-printed prototype and the time elapsed to obtain it. Evaluation results revealed that the overall performance of Kangaroo Mother Care and the embrace warmer was 75 ± 1.4% and 66.7 ± 1.5%, respectively, while the overall performance of our Handy incubator was 91.7 ± 1.6%, thereby our cost-effective Handy incubator surpassed existing intensive care methods. The future step is associating the Handy incubator with more specifications and advancements.

  5. 3D numerical simulation on heat transfer performance of a cylindrical liquid immersion solar receiver

    International Nuclear Information System (INIS)

    Xiang Haijun; Wang Yiping; Zhu Li; Han Xinyue; Sun Yong; Zhao Zhengjian

    2012-01-01

    Highlights: ► Establishment of a three-dimensional numerical simulation model of a cylindrical liquid immersion solar receiver. ► Determination of model parameters and validation of the model by using the real-collected data. ► Optimization of liquid flow rate and fin’s structure for better heat transfer performance. - Abstract: Liquid immersion cooling for a cylindrical solar receiver in a dish concentrator photovoltaic system has been experimentally verified to be a promising method of removing surplus heat from densely packed solar cells. In the present study, a three-dimensional (3D) numerical simulation model of the prototype was established for better understanding the mechanism of the direct-contact heat transfer process. With the selection of standard k–ε turbulent model, the detailed simulation results of velocity field and temperature characteristics were obtained. The heat transfer performance of two structural modules (bare module and finned module) under actual weather conditions was simulated. It was found that the predicted temperature distribution of the two structural modules at the axial and lateral direction was in good agreement with the experimental data. Based on the validated simulation model, the influence of liquid flow rate and module geometric parameters on the cell temperature was then investigated. The simulated results indicated that the cell module with fin height of 4 mm and fin number of 11 has the best heat transfer performance and will be used in further works.

  6. 3-D electromagnetic plasma particle simulations on the Intel Delta parallel computer

    International Nuclear Information System (INIS)

    Wang, J.; Liewer, P.C.

    1994-01-01

    A three-dimensional electromagnetic PIC code has been developed on the 512 node Intel Touchstone Delta MIMD parallel computer. This code is based on the General Concurrent PIC algorithm which uses a domain decomposition to divide the computation among the processors. The 3D simulation domain can be partitioned into 1-, 2-, or 3-dimensional sub-domains. Particles must be exchanged between processors as they move among the subdomains. The Intel Delta allows one to use this code for very-large-scale simulations (i.e. over 10 8 particles and 10 6 grid cells). The parallel efficiency of this code is measured, and the overall code performance on the Delta is compared with that on Cray supercomputers. It is shown that their code runs with a high parallel efficiency of ≥ 95% for large size problems. The particle push time achieved is 115 nsecs/particle/time step for 162 million particles on 512 nodes. Comparing with the performance on a single processor Cray C90, this represents a factor of 58 speedup. The code uses a finite-difference leap frog method for field solve which is significantly more efficient than fast fourier transforms on parallel computers. The performance of this code on the 128 node Cray T3D will also be discussed

  7. Optical and Acoustic Sensor-Based 3D Ball Motion Estimation for Ball Sport Simulators

    Directory of Open Access Journals (Sweden)

    Sang-Woo Seo

    2018-04-01

    Full Text Available Estimation of the motion of ball-shaped objects is essential for the operation of ball sport simulators. In this paper, we propose an estimation system for 3D ball motion, including speed and angle of projection, by using acoustic vector and infrared (IR scanning sensors. Our system is comprised of three steps to estimate a ball motion: sound-based ball firing detection, sound source localization, and IR scanning for motion analysis. First, an impulsive sound classification based on the mel-frequency cepstrum and feed-forward neural network is introduced to detect the ball launch sound. An impulsive sound source localization using a 2D microelectromechanical system (MEMS microphones and delay-and-sum beamforming is presented to estimate the firing position. The time and position of a ball in 3D space is determined from a high-speed infrared scanning method. Our experimental results demonstrate that the estimation of ball motion based on sound allows a wider activity area than similar camera-based methods. Thus, it can be practically applied to various simulations in sports such as soccer and baseball.

  8. 3D nozzle flow simulations including state-to-state kinetics calculation

    Science.gov (United States)

    Cutrone, L.; Tuttafesta, M.; Capitelli, M.; Schettino, A.; Pascazio, G.; Colonna, G.

    2014-12-01

    In supersonic and hypersonic flows, thermal and chemical non-equilibrium is one of the fundamental aspects that must be taken into account for the accurate characterization of the plasma. In this paper, we present an optimized methodology to approach plasma numerical simulation by state-to-state kinetics calculations in a fully 3D Navier-Stokes CFD solver. Numerical simulations of an expanding flow are presented aimed at comparing the behavior of state-to-state chemical kinetics models with respect to the macroscopic thermochemical non-equilibrium models that are usually used in the numerical computation of high temperature hypersonic flows. The comparison is focused both on the differences in the numerical results and on the computational effort associated with each approach.

  9. 3D simulations and modeling of new low capacitance silicon pixel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Bo; Li, Yu Yun [School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 (China); Center for Semiconductor Particle and photon Imaging Detector Development and Fabrication, Xiangtan University, Xiangtan 411105 (China); Li, Zheng, E-mail: zhengli58@gmail.com [School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 (China); Center for Semiconductor Particle and photon Imaging Detector Development and Fabrication, Xiangtan University, Xiangtan 411105 (China)

    2016-09-21

    With signal to noise ratio (S/N) being a key parameter of a high performance detector, reducing the detector noise has been one of the main tasks in detector development. A new low capacitance silicon pixel detector is proposed, which is based on a new electrode geometry with reduced effective electrode area while keeping the sensitive volume unchanged. Detector electrical characteristics including electrostatic potential, electric field, full depletion voltage, and capacitance have been simulated in detail using a 3D TCAD tool. From these simulations and calculations, we confirm that the new detector structure has a much reduced capacitance (by a factor of 3) as compared to the traditional pixel detectors with the same sensitive volume. This reduction in detector capacitance can certainly improve the detector signal to noise ratio. However, the full depletion voltage for the new structure is larger than that of the traditional one due to the small electrode effect.

  10. 3-D CFD simulations of hydrodynamics in the Sulejow dam reservoir

    Directory of Open Access Journals (Sweden)

    Ziemińska-Stolarska Aleksandra

    2015-12-01

    Full Text Available This paper reports the processes by which a single-phase 3-D CFD model of hydrodynamics in a 17-km-long dam reservoir was developed, verified and tested. A simplified VOF model of flow was elaborated to determine the effect of wind on hydrodynamics in the lake. A hexahedral mesh with over 17 million elements and a k-ω SST turbulence model were defined for single-phase simulations in steady-state conditions. The model was verified on the basis of the extensive flow measurements (StreamPro ADCP, USA. Excellent agreement (average error of less than 10% between computed and measured velocity profiles was found. The simulation results proved a strong effect of wind on hydrodynamics in the lake, especially on the development of the water circulation pattern in the lacustrine zone.

  11. A geographic information system-based 3D city estate modeling and simulation system

    Science.gov (United States)

    Chong, Xiaoli; Li, Sha

    2015-12-01

    This paper introduces a 3D city simulation system which is based on geographic information system (GIS), covering all commercial housings of the city. A regional- scale, GIS-based approach is used to capture, describe, and track the geographical attributes of each house in the city. A sorting algorithm of "Benchmark + Parity Rate" is developed to cluster houses with similar spatial and construction attributes. This system is applicable for digital city modeling, city planning, housing evaluation, housing monitoring, and visualizing housing transaction. Finally, taking Jingtian area of Shenzhen as an example, the each unit of 35,997 houses in the area could be displayed, tagged, and easily tracked by the GIS-based city modeling and simulation system. The match market real conditions well and can be provided to house buyers as reference.

  12. 3D ion-scale dynamics of BBFs and their associated emissions in Earth's magnetotail using 3D hybrid simulations and MMS multi-spacecraft observations

    Science.gov (United States)

    Breuillard, H.; Aunai, N.; Le Contel, O.; Catapano, F.; Alexandrova, A.; Retino, A.; Cozzani, G.; Gershman, D. J.; Giles, B. L.; Khotyaintsev, Y. V.; Lindqvist, P. A.; Ergun, R.; Strangeway, R. J.; Russell, C. T.; Magnes, W.; Plaschke, F.; Nakamura, R.; Fuselier, S. A.; Turner, D. L.; Schwartz, S. J.; Torbert, R. B.; Burch, J.

    2017-12-01

    Transient and localized jets of hot plasma, also known as Bursty Bulk Flows (BBFs), play a crucial role in Earth's magnetotail dynamics because the energy input from the solar wind is partly dissipated in their vicinity, notably in their embedded dipolarization front (DF). This dissipation is in the form of strong low-frequency waves that can heat and accelerate energetic particles up to the high-latitude plasma sheet. The ion-scale dynamics of BBFs have been revealed by the Cluster and THEMIS multi-spacecraft missions. However, the dynamics of BBF propagation in the magnetotail are still under debate due to instrumental limitations and spacecraft separation distances, as well as simulation limitations. The NASA/MMS fleet, which features unprecedented high time resolution instruments and four spacecraft separated by kinetic-scale distances, has also shown recently that the DF normal dynamics and its associated emissions are below the ion gyroradius scale in this region. Large variations in the dawn-dusk direction were also observed. However, most of large-scale simulations are using the MHD approach and are assumed 2D in the XZ plane. Thus, in this study we take advantage of both multi-spacecraft observations by MMS and large-scale 3D hybrid simulations to investigate the 3D dynamics of BBFs and their associated emissions at ion-scale in Earth's magnetotail, and their impact on particle heating and acceleration.

  13. Energization and Transport in 3D Kinetic Simulations of MMS Magnetopause Reconnection Site Encounters with Varying Guide Fields

    Science.gov (United States)

    Le, A.; Daughton, W. S.; Ohia, O.; Chen, L. J.; Liu, Y. H.

    2017-12-01

    We present 3D fully kinetic simulations of asymmetric reconnection with plasma parameters matching MMS magnetopause diffusion region crossings with varying guide fields of 0.1 [Burch et al., Science (2016)], 0.4 [Chen et al. JGR (2017)], and 1 [Burch and Phan, GRL (2016] of the reconnecting sheath field. Strong diamagnetic drifts across the magnetopause current sheet drive lower-hybrid drift instabilities (LHDI) over a range of wavelengths [Daughton, PoP (2003); Roytershteyn et al., PRL (2012)] that develop into a turbulent state. Magnetic field tracing diagnostics are employed to characterize the turbulent magnetic geometry and to evaluate the global reconnection rate. The contributions to Ohm's law are evaluated field line by field line, including time-averaged diagnostics that allow the quantification of anomalous resistivity and viscosity. We examine how fluctuating electric fields and chaotic magnetic field lines contribute to particle mixing across the separatrix, and we characterize the accelerated electron distributions that form under varying magnetic shear or guide field. The LHDI turbulence is found to strongly enhance transport and parallel electron heating in 3D compared to 2D, particularly along the magnetospheric separatrix [Le et al., GRL (2017)]. The PIC simulation results are compared to MMS observations.

  14. Classroom Simulation for Trainee Teachers Using 3D Virtual Environments and Simulated Smartbot Student Behaviours

    OpenAIRE

    Alotaibi, Fahad Mazaed

    2014-01-01

    his thesis consists of an analysis of a classroom simulation using a Second Life (SL) experiment that aims to investigate the teaching impact on smartbots (virtual students) from trainee teacher avatars with respect to interaction, simulated behaviour, and observed teaching roles. The classroom-based SL experiments’ motivation is to enable the trainee teacher to acquire the necessary skills and experience to manage a real classroom environment through simulations of a real classroom. This ty...

  15. Influences of 3D PET scanner components on increased scatter evaluated by a Monte Carlo simulation

    Science.gov (United States)

    Hirano, Yoshiyuki; Koshino, Kazuhiro; Iida, Hidehiro

    2017-05-01

    Monte Carlo simulation is widely applied to evaluate the performance of three-dimensional positron emission tomography (3D-PET). For accurate scatter simulations, all components that generate scatter need to be taken into account. The aim of this work was to identify the components that influence scatter. The simulated geometries of a PET scanner were: a precisely reproduced configuration including all of the components; a configuration with the bed, the tunnel and shields; a configuration with the bed and shields; and the simplest geometry with only the bed. We measured and simulated the scatter fraction using two different set-ups: (1) as prescribed by NEMA-NU 2007 and (2) a similar set-up but with a shorter line source, so that all activity was contained only inside the field-of-view (FOV), in order to reduce influences of components outside the FOV. The scatter fractions for the two experimental set-ups were, respectively, 45% and 38%. Regarding the geometrical configurations, the former two configurations gave simulation results in good agreement with the experimental results, but simulation results of the simplest geometry were significantly different at the edge of the FOV. From the simulation of the precise configuration, the object (scatter phantom) was the source of more than 90% of the scatter. This was also confirmed by visualization of photon trajectories. Then, the bed and the tunnel were mainly the sources of the rest of the scatter. From the simulation results, we concluded that the precise construction was not needed; the shields, the tunnel, the bed and the object were sufficient for accurate scatter simulations.

  16. Comparison Between 2D and 3D Simulations of Rate Dependent Friction Using DEM

    Science.gov (United States)

    Wang, C.; Elsworth, D.

    2017-12-01

    Rate-state dependent constitutive laws of frictional evolution have been successful in representing many of the first- and second- order components of earthquake rupture. Although this constitutive law has been successfully applied in numerical models, difficulty remains in efficient implementation of this constitutive law in computationally-expensive granular mechanics simulations using discrete element methods (DEM). This study introduces a novel approach in implementing a rate-dependent constitutive relation of contact friction into DEM. This is essentially an implementation of a slip-weakening constitutive law onto local particle contacts without sacrificing computational efficiency. This implementation allows the analysis of slip stability of simulated fault gouge materials. Velocity-stepping experiments are reported on both uniform and textured distributions of quartz and talc as 3D analogs of gouge mixtures. Distinct local slip stability parameters (a-b) are assigned to the quartz and talc, respectively. We separately vary talc content from 0 to 100% in the uniform mixtures and talc layer thickness from 1 to 20 particles in the textured mixtures. Applied shear displacements are cycled through velocities of 1μm/s and 10μm/s. Frictional evolution data are collected and compared to 2D simulation results. We show that dimensionality significantly impacts the evolution of friction. 3D simulation results are more representative of laboratory observed behavior and numerical noise is shown at a magnitude of 0.01 in terms of friction coefficient. Stability parameters (a-b) can be straightforwardly obtained from analyzing velocity steps, and are different from locally assigned (a-b) values. Sensitivity studies on normal stress, shear velocity, particle size, local (a-b) values, and characteristic slip distance (Dc) show that the implementation is sensitive to local (a-b) values and relations between (Dc) and particle size.

  17. A simulation technique for 3D MR-guided acoustic radiation force imaging

    International Nuclear Information System (INIS)

    Payne, Allison; Bever, Josh de; Farrer, Alexis; Coats, Brittany; Parker, Dennis L.; Christensen, Douglas A.

    2015-01-01

    Purpose: In magnetic resonance-guided focused ultrasound (MRgFUS) therapies, the in situ characterization of the focal spot location and quality is critical. MR acoustic radiation force imaging (MR-ARFI) is a technique that measures the tissue displacement caused by the radiation force exerted by the ultrasound beam. This work presents a new technique to model the displacements caused by the radiation force of an ultrasound beam in a homogeneous tissue model. Methods: When a steady-state point-source force acts internally in an infinite homogeneous medium, the displacement of the material in all directions is given by the Somigliana elastostatic tensor. The radiation force field, which is caused by absorption and reflection of the incident ultrasound intensity pattern, will be spatially distributed, and the tensor formulation takes the form of a convolution of a 3D Green’s function with the force field. The dynamic accumulation of MR phase during the ultrasound pulse can be theoretically accounted for through a time-of-arrival weighting of the Green’s function. This theoretical model was evaluated experimentally in gelatin phantoms of varied stiffness (125-, 175-, and 250-bloom). The acoustic and mechanical properties of the phantoms used as parameters of the model were measured using independent techniques. Displacements at focal depths of 30- and 45-mm in the phantoms were measured by a 3D spin echo MR-ARFI segmented-EPI sequence. Results: The simulated displacements agreed with the MR-ARFI measured displacements for all bloom values and focal depths with a normalized RMS difference of 0.055 (range 0.028–0.12). The displacement magnitude decreased and the displacement pattern broadened with increased bloom value for both focal depths, as predicted by the theory. Conclusions: A new technique that models the displacements caused by the radiation force of an ultrasound beam in a homogeneous tissue model theory has been rigorously validated through comparison

  18. GADEN: A 3D Gas Dispersion Simulator for Mobile Robot Olfaction in Realistic Environments.

    Science.gov (United States)

    Monroy, Javier; Hernandez-Bennets, Victor; Fan, Han; Lilienthal, Achim; Gonzalez-Jimenez, Javier

    2017-06-23

    This work presents a simulation framework developed under the widely used Robot Operating System (ROS) to enable the validation of robotics systems and gas sensing algorithms under realistic environments. The framework is rooted in the principles of computational fluid dynamics and filament dispersion theory, modeling wind flow and gas dispersion in 3D real-world scenarios (i.e., accounting for walls, furniture, etc.). Moreover, it integrates the simulation of different environmental sensors, such as metal oxide gas sensors, photo ionization detectors, or anemometers. We illustrate the potential and applicability of the proposed tool by presenting a simulation case in a complex and realistic office-like environment where gas leaks of different chemicals occur simultaneously. Furthermore, we accomplish quantitative and qualitative validation by comparing our simulated results against real-world data recorded inside a wind tunnel where methane was released under different wind flow profiles. Based on these results, we conclude that our simulation framework can provide a good approximation to real world measurements when advective airflows are present in the environment.

  19. The Shock Dynamics of Heterogeneous YSO Jets: 3D Simulations Meet Multi-epoch Observations

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, E. C.; Frank, A. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Hartigan, P. [Department of Physics and Astronomy, Rice University, 6100 S. Main, Houston, TX 77521-1892 (United States); Lebedev, S. V. [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom)

    2017-03-10

    High-resolution observations of young stellar object (YSO) jets show them to be composed of many small-scale knots or clumps. In this paper, we report results of 3D numerical simulations designed to study how such clumps interact and create morphologies and kinematic patterns seen in emission line observations. Our simulations focus on clump scale dynamics by imposing velocity differences between spherical, over-dense regions, which then lead to the formation of bow shocks as faster clumps overtake slower material. We show that much of the spatial structure apparent in emission line images of jets arises from the dynamics and interactions of these bow shocks. Our simulations show a variety of time-dependent features, including bright knots associated with Mach stems where the shocks intersect, a “frothy” emission structure that arises from the presence of the Nonlinear Thin Shell Instability along the surfaces of the bow shocks, and the merging and fragmentation of clumps. Our simulations use a new non-equilibrium cooling method to produce synthetic emission maps in H α and [S ii]. These are directly compared to multi-epoch Hubble Space Telescope observations of Herbig–Haro jets. We find excellent agreement between features seen in the simulations and the observations in terms of both proper motion and morphologies. Thus we conclude that YSO jets may be dominated by heterogeneous structures and that interactions between these structures and the shocks they produce can account for many details of YSO jet evolution.

  20. The simulation of 3D mass models in 2D digital mammography and breast tomosynthesis

    International Nuclear Information System (INIS)

    Shaheen, Eman; De Keyzer, Frederik; Bosmans, Hilde; Ongeval, Chantal Van; Dance, David R.; Young, Kenneth C.

    2014-01-01

    Purpose: This work proposes a new method of building 3D breast mass models with different morphological shapes and describes the validation of the realism of their appearance after simulation into 2D digital mammograms and breast tomosynthesis images. Methods: Twenty-five contrast enhanced MRI breast lesions were collected and each mass was manually segmented in the three orthogonal views: sagittal, coronal, and transversal. The segmented models were combined, resampled to have isotropic voxel sizes, triangularly meshed, and scaled to different sizes. These masses were referred to as nonspiculated masses and were then used as nuclei onto which spicules were grown with an iterative branching algorithm forming a total of 30 spiculated masses. These 55 mass models were projected into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. The realism of the appearance of these mass models was assessed by five radiologists via receiver operating characteristic (ROC) analysis when compared to 54 real masses. All lesions were also given a breast imaging reporting and data system (BIRADS) score. The data sets of 2D mammography and tomosynthesis were read separately. The Kendall's coefficient of concordance was used for the interrater observer agreement assessment for the BIRADS scores per modality. Further paired analysis, using the Wilcoxon signed rank test, of the BIRADS assessment between 2D and tomosynthesis was separately performed for the real masses and for the simulated masses. Results: The area under the ROC curves, averaged over all observers, was 0.54 (95% confidence interval [0.50, 0.66]) for the 2D study, and 0.67 (95% confidence interval [0.55, 0.79]) for the tomosynthesis study. According to the BIRADS scores, the nonspiculated and the spiculated masses varied in their degrees of malignancy from normal (BIRADS 1) to highly

  1. The simulation of 3D mass models in 2D digital mammography and breast tomosynthesis.

    Science.gov (United States)

    Shaheen, Eman; De Keyzer, Frederik; Bosmans, Hilde; Dance, David R; Young, Kenneth C; Van Ongeval, Chantal

    2014-08-01

    This work proposes a new method of building 3D breast mass models with different morphological shapes and describes the validation of the realism of their appearance after simulation into 2D digital mammograms and breast tomosynthesis images. Twenty-five contrast enhanced MRI breast lesions were collected and each mass was manually segmented in the three orthogonal views: sagittal, coronal, and transversal. The segmented models were combined, resampled to have isotropic voxel sizes, triangularly meshed, and scaled to different sizes. These masses were referred to as nonspiculated masses and were then used as nuclei onto which spicules were grown with an iterative branching algorithm forming a total of 30 spiculated masses. These 55 mass models were projected into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. The realism of the appearance of these mass models was assessed by five radiologists via receiver operating characteristic (ROC) analysis when compared to 54 real masses. All lesions were also given a breast imaging reporting and data system (BIRADS) score. The data sets of 2D mammography and tomosynthesis were read separately. The Kendall's coefficient of concordance was used for the interrater observer agreement assessment for the BIRADS scores per modality. Further paired analysis, using the Wilcoxon signed rank test, of the BIRADS assessment between 2D and tomosynthesis was separately performed for the real masses and for the simulated masses. The area under the ROC curves, averaged over all observers, was 0.54 (95% confidence interval [0.50, 0.66]) for the 2D study, and 0.67 (95% confidence interval [0.55, 0.79]) for the tomosynthesis study. According to the BIRADS scores, the nonspiculated and the spiculated masses varied in their degrees of malignancy from normal (BIRADS 1) to highly suggestive for malignancy (BIRADS 5

  2. The simulation of 3D mass models in 2D digital mammography and breast tomosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Shaheen, Eman, E-mail: eman.shaheen@uzleuven.be; De Keyzer, Frederik; Bosmans, Hilde; Ongeval, Chantal Van [Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium); Dance, David R.; Young, Kenneth C. [National Coordinating Centre for the Physics of Mammography, Royal Surrey County Hospital, Guildford GU2 7XX, United Kingdom and Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2014-08-15

    Purpose: This work proposes a new method of building 3D breast mass models with different morphological shapes and describes the validation of the realism of their appearance after simulation into 2D digital mammograms and breast tomosynthesis images. Methods: Twenty-five contrast enhanced MRI breast lesions were collected and each mass was manually segmented in the three orthogonal views: sagittal, coronal, and transversal. The segmented models were combined, resampled to have isotropic voxel sizes, triangularly meshed, and scaled to different sizes. These masses were referred to as nonspiculated masses and were then used as nuclei onto which spicules were grown with an iterative branching algorithm forming a total of 30 spiculated masses. These 55 mass models were projected into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. The realism of the appearance of these mass models was assessed by five radiologists via receiver operating characteristic (ROC) analysis when compared to 54 real masses. All lesions were also given a breast imaging reporting and data system (BIRADS) score. The data sets of 2D mammography and tomosynthesis were read separately. The Kendall's coefficient of concordance was used for the interrater observer agreement assessment for the BIRADS scores per modality. Further paired analysis, using the Wilcoxon signed rank test, of the BIRADS assessment between 2D and tomosynthesis was separately performed for the real masses and for the simulated masses. Results: The area under the ROC curves, averaged over all observers, was 0.54 (95% confidence interval [0.50, 0.66]) for the 2D study, and 0.67 (95% confidence interval [0.55, 0.79]) for the tomosynthesis study. According to the BIRADS scores, the nonspiculated and the spiculated masses varied in their degrees of malignancy from normal (BIRADS 1) to highly

  3. 3D nonlinear magnetohydrodynamic simulations of macroscopic internal instabilities in tokamak plasmas

    International Nuclear Information System (INIS)

    Krebs, Isabel

    2017-01-01

    The Hybrid tokamak scenario provides favorable confinement and stability properties and is a candidate for an ITER Advanced tokamak scenario. It is characterized by low magnetic shear and a value of the safety factor (q) close to unity in the plasma core resulting in the absence of sawteeth. As transport calculations for some Hybrid discharges predict that the applied heat and current sources drive the value of q on axis below unity, there seems to be an unexplained mechanism which leads to a redistribution of the toroidal current density such that q∼1 is maintained in the center of the discharge. This mechanism is referred to as magnetic flux pumping. Besides the advantageous effect of preventing sawtoothing which also prevents the seeding of neoclassical tearing modes by sawteeth, magnetic flux pumping as well facilitates the drive of plasma current through external current sources. As the current density is automatically redistributed, current sources can be applied in the plasma center, where they are most efficient. The aim of this work is to contribute to the understanding of magnetic flux pumping in Hybrid discharges. A flux pumping mechanism is found in 3D non-linear MHD simulations leading to stationary states with a helically perturbed core and a at central safety factor profile with values close to unity. It is proposed earlier that the main effect responsible for this flux pumping mechanism is that the magnetic field and velocity perturbations resulting from a saturated quasi-interchange instability combine to generate an effective negative loop voltage via a dynamo effect. In this thesis, a large set of long-term 3D nonlinear single-fluid MHD simulations in toroidal geometry are presented which have been performed by means of the high-order finite element code M3D-C. The simulations result in asymptotic states that either exhibit sawtooth-like reconnection cycles, or correspond to sawtooth-free stationary states where the central safety factor is

  4. 3D nonlinear magnetohydrodynamic simulations of macroscopic internal instabilities in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, Isabel

    2017-08-08

    The Hybrid tokamak scenario provides favorable confinement and stability properties and is a candidate for an ITER Advanced tokamak scenario. It is characterized by low magnetic shear and a value of the safety factor (q) close to unity in the plasma core resulting in the absence of sawteeth. As transport calculations for some Hybrid discharges predict that the applied heat and current sources drive the value of q on axis below unity, there seems to be an unexplained mechanism which leads to a redistribution of the toroidal current density such that q∼1 is maintained in the center of the discharge. This mechanism is referred to as magnetic flux pumping. Besides the advantageous effect of preventing sawtoothing which also prevents the seeding of neoclassical tearing modes by sawteeth, magnetic flux pumping as well facilitates the drive of plasma current through external current sources. As the current density is automatically redistributed, current sources can be applied in the plasma center, where they are most efficient. The aim of this work is to contribute to the understanding of magnetic flux pumping in Hybrid discharges. A flux pumping mechanism is found in 3D non-linear MHD simulations leading to stationary states with a helically perturbed core and a at central safety factor profile with values close to unity. It is proposed earlier that the main effect responsible for this flux pumping mechanism is that the magnetic field and velocity perturbations resulting from a saturated quasi-interchange instability combine to generate an effective negative loop voltage via a dynamo effect. In this thesis, a large set of long-term 3D nonlinear single-fluid MHD simulations in toroidal geometry are presented which have been performed by means of the high-order finite element code M3D-C. The simulations result in asymptotic states that either exhibit sawtooth-like reconnection cycles, or correspond to sawtooth-free stationary states where the central safety factor is

  5. Surface 3D nanostructuring by tightly focused laser pulse: simulations by Lagrangian code and molecular dynamics

    Science.gov (United States)

    Inogamov, Nail A.; Zhakhovsky, Vasily V.

    2016-02-01

    There are many important applications in which the ultrashort diffraction-limited and therefore tightly focused laser pulses irradiates metal films mounted on dielectric substrate. Here we present the detailed picture of laser peeling and 3D structure formation of the thin (relative to a depth of a heat affected zone in the bulk targets) gold films on glass substrate. The underlying physics of such diffraction-limited laser peeling was not well understood previously. Our approach is based on a physical model which takes into consideration the new calculations of the two-temperature (2T) equation of state (2T EoS) and the two-temperature transport coefficients together with the coupling parameter between electron and ion subsystems. The usage of the 2T EoS and the kinetic coefficients is required because absorption of an ultrashort pulse with duration of 10-1000 fs excites electron subsystem of metal and transfers substance into the 2T state with hot electrons (typical electron temperatures 1-3 eV) and much colder ions. It is shown that formation of submicrometer-sized 3D structures is a result of the electron-ion energy transfer, melting, and delamination of film from substrate under combined action of electron and ion pressures, capillary deceleration of the delaminated liquid metal or semiconductor, and ultrafast freezing of molten material. We found that the freezing is going in non-equilibrium regime with strongly overcooled liquid phase. In this case the Stefan approximation is non-applicable because the solidification front speed is limited by the diffusion rate of atoms in the molten material. To solve the problem we have developed the 2T Lagrangian code including all this reach physics in. We also used the high-performance combined Monte- Carlo and molecular dynamics code for simulation of surface 3D nanostructuring at later times after completion of electron-ion relaxation.

  6. Mammogram synthesis using a 3D simulation. I. Breast tissue model and image acquisition simulation

    International Nuclear Information System (INIS)

    Bakic, Predrag R.; Albert, Michael; Brzakovic, Dragana; Maidment, Andrew D. A.

    2002-01-01

    A method is proposed for generating synthetic mammograms based upon simulations of breast tissue and the mammographic imaging process. A computer breast model has been designed with a realistic distribution of large and medium scale tissue structures. Parameters controlling the size and placement of simulated structures (adipose compartments and ducts) provide a method for consistently modeling images of the same simulated breast with modified position or acquisition parameters. The mammographic imaging process is simulated using a compression model and a model of the x-ray image acquisition process. The compression model estimates breast deformation using tissue elasticity parameters found in the literature and clinical force values. The synthetic mammograms were generated by a mammogram acquisition model using a monoenergetic parallel beam approximation applied to the synthetically compressed breast phantom

  7. Effects of Accretionary Prisms on 3-D Long-Period Ground Motion Simulations

    Science.gov (United States)

    Guo, Y.; Koketsu, K.; Miyake, H.

    2014-12-01

    The accretionary prism along the subduction zones such as the Middle America trench or the Nankai trough is considered as an important factor affecting the generation and propagation of long-period ground motions. In Japan, the great earthquake along the Nankai subduction zone which is expected to occur in the near future can generate large long-period ground motions in the metropolitan areas such as Osaka, Nagoya and Tokyo. To investigate the effect of accretionary prism on long-period ground motions, we performed simulations of long-period ground motions for the event (Mw 7.1) that occurred off the Kii peninsula, Japan, at 10:07 on 5 September 2004 (UTC). Our simulation model ranged from the Kinki region to the Kanto region, and included the Osaka, Nobi and Kanto basin. We calculated long-period ground motions for four types of 3-D velocity structure models: (a) model with the accretionary prism (reference model), (b) model where accretionary prism has different 3-D geometry from the reference model, (c) model with the accretionary prism whose velocity, density and Q-value are shifted, (d) model without the accretionary prism. We compared the waveforms calculated for these models and concluded that the accretionary prism along the Nankai subduction zone plays roles in reducing the amplitude of direct waves and extending the duration of coda waves. This is attributed to the trap effect of accretionary prism. Our simulation also suggested that, the edge geometry along the landward side of accretionary prism has major effects on the processes of generation and propagation of long-period ground motions.

  8. The dark side of photovoltaic — 3D simulation of glare assessing risk and discomfort

    International Nuclear Information System (INIS)

    Rose, Thomas; Wollert, Alexander

    2015-01-01

    Photovoltaic (PV) systems form an important force in the implementation of renewable energies, but as we all know, the force has always its dark side. Besides efficiency considerations and discussions about architectures of power distribution networks, the increasing numbers of installations of PV systems for implementing renewable energies have secondary effects. PV systems can generate glare due to optical reflections and hence might be a serious concern. On the one hand, glare could affect safety, e.g. regarding traffic. On the other hand, glare is a constant source of discomfort in vicinities of PV systems. Hence, assessment of glare is decisive for the success of renewable energies near municipalities and traffic zones for the success of solar power. Several courts decided on the change of PV systems and even on their de-installation because of glare effects. Thus, location-based assessments are required to limit potential reflections and to avoid risks for public infrastructure or discomfort of residents. The question arises on how to calculate reflections accurately according to the environment's topography. Our approach is founded in a 3D-based simulation methodology to calculate and visualize reflections based on the geometry of the environment of PV systems. This computational model is implemented by an interactive tool for simulation and visualization. Hence, project planners receive flexible assistance for adjusting the parameters of solar panels amid the planning process and in particular before the installation of a PV system. - Highlights: • Solar panels cause glare that impacts neighborhoods and traffic infrastructures. • Glare might cause disability and discomfort. • 3D environment for the calculation of glare • Interactive tool to simulate and visualize reflections • Impact assessment of solar power plant farms

  9. The dark side of photovoltaic — 3D simulation of glare assessing risk and discomfort

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Thomas; Wollert, Alexander

    2015-04-15

    Photovoltaic (PV) systems form an important force in the implementation of renewable energies, but as we all know, the force has always its dark side. Besides efficiency considerations and discussions about architectures of power distribution networks, the increasing numbers of installations of PV systems for implementing renewable energies have secondary effects. PV systems can generate glare due to optical reflections and hence might be a serious concern. On the one hand, glare could affect safety, e.g. regarding traffic. On the other hand, glare is a constant source of discomfort in vicinities of PV systems. Hence, assessment of glare is decisive for the success of renewable energies near municipalities and traffic zones for the success of solar power. Several courts decided on the change of PV systems and even on their de-installation because of glare effects. Thus, location-based assessments are required to limit potential reflections and to avoid risks for public infrastructure or discomfort of residents. The question arises on how to calculate reflections accurately according to the environment's topography. Our approach is founded in a 3D-based simulation methodology to calculate and visualize reflections based on the geometry of the environment of PV systems. This computational model is implemented by an interactive tool for simulation and visualization. Hence, project planners receive flexible assistance for adjusting the parameters of solar panels amid the planning process and in particular before the installation of a PV system. - Highlights: • Solar panels cause glare that impacts neighborhoods and traffic infrastructures. • Glare might cause disability and discomfort. • 3D environment for the calculation of glare • Interactive tool to simulate and visualize reflections • Impact assessment of solar power plant farms.

  10. Global smooth solutions of 3-D null-form wave equations in exterior domains with Neumann boundary conditions

    Science.gov (United States)

    Jun, Li; Huicheng, Yin

    2018-05-01

    The paper is devoted to investigating long time behavior of smooth small data solutions to 3-D quasilinear wave equations outside of compact convex obstacles with Neumann boundary conditions. Concretely speaking, when the surface of a 3-D compact convex obstacle is smooth and the quasilinear wave equation fulfills the null condition, we prove that the smooth small data solution exists globally provided that the Neumann boundary condition on the exterior domain is given. One of the main ingredients in the current paper is the establishment of local energy decay estimates of the solution itself. As an application of the main result, the global stability to 3-D static compressible Chaplygin gases in exterior domain is shown under the initial irrotational perturbation with small amplitude.

  11. Simulation of an MSLB scenario using the 3D neutron kinetic core model DYN3D coupled with the CFD software Trio-U

    Energy Technology Data Exchange (ETDEWEB)

    Grahn, Alexander, E-mail: a.grahn@hzdr.de; Gommlich, André; Kliem, Sören; Bilodid, Yurii; Kozmenkov, Yaroslav

    2017-04-15

    Highlights: • Improved thermal-hydraulic description of nuclear reactor cores. • Providing reactor dynamics code with realistic thermal-hydraulic boundary conditions. • Possibility of three-dimensional flow phenomena in the core, such as cross flow, flow reversal. • Simulation at higher spatial resolution as compared to system codes. - Abstract: In the framework of the European project NURESAFE, the reactor dynamics code DYN3D, developed at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), was coupled with the Computational Fluid Dynamics (CFD) solver Trio-U, developed at CEA France, in order to replace DYN3D’s one-dimensional hydraulic part with a full three-dimensional description of the coolant flow in the reactor core at higher spatial resolution. The present document gives an introduction into the coupling method and shows results of its application to the simulation of a Main Steamline Break (MSLB) accident of a Pressurised Water Reactor (PWR).

  12. A GIS-Based 3D Simulation for Occupant Evacuation in a Building

    Institute of Scientific and Technical Information of China (English)

    TANG Fangqin; ZHANG Xin

    2008-01-01

    The evacuation efficiency of building plans is of obvious importance to the public safety.The cem- plexity of building plans,however,makes it difficult for the efficiency evaluation.This paper presents a com- putational model AutoEscape,which can simulate the evacuation process for any given occupant distribu. Uon in buildings.Designed as an extensible multi-level structure, the model constructs the geometry level and occupant level and establishes the interactions between levels.The GIS-based environmental analysis is realized to automatically generate the geometric representation and formulate the cognition of agents. The multi-agent based technology is employed to simulate the crowd behaviom with autonomously acting individuals.A visualization component,which provides 3D free observations for the simulation process,is developed on the platform of OGRE and integrated into the system interface in form of ActiveX control.Fi- nally,a case study has been conducted and the results have been compared with the results of an existing model to show the reliability and capacity of AutoEscape simulation.

  13. Ventriculostomy Simulation Using Patient-Specific Ventricular Anatomy, 3D Printing, and Hydrogel Casting.

    Science.gov (United States)

    Ryan, Justin R; Chen, Tsinsue; Nakaji, Peter; Frakes, David H; Gonzalez, L Fernando

    2015-11-01

    Educational simulators provide a means for students and experts to learn and refine surgical skills. Educators can leverage the strengths of medical simulators to effectively teach complex and high-risk surgical procedures, such as placement of an external ventricular drain. Our objective was to develop a cost-effective, patient-derived medical simulacrum for cerebral lateral ventriculostomy. A cost-effective, patient-derived medical simulacrum was developed for placement of an external lateral ventriculostomy. Elastomeric and gel casting techniques were used to achieve realistic brain geometry and material properties. 3D printing technology was leveraged to develop accurate cranial properties and dimensions. An economical, gravity-driven pump was developed to provide normal and abnormal ventricular pressures. A small pilot study was performed to gauge simulation efficacy using a technology acceptance model. An accurate geometric representation of the brain was developed with independent lateral cerebral ventricular chambers. A gravity-driven pump pressurized the ventricular cavities to physiologic values. A qualitative study illustrated that the simulation has potential as an educational tool to train medical professionals in the ventriculostomy procedure. The ventricular simulacrum can improve learning in a medical education environment. Rapid prototyping and multi-material casting techniques can produce patient-derived models for cost-effective and realistic surgical training scenarios. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Finite element simulation of HIP-process to produce 3d near net shape parts

    International Nuclear Information System (INIS)

    Zadeh, M.K.

    1996-01-01

    One of the major problems when producing powder metallurgy parts through hot isostatic pressing (HIP) is the non homogeneous shrinkage of HIP-capsule during the process. This leads to time and cost consuming machining of the HIP parts. In order to reduce the machining to a minimum, one can try to simulate the HIP-process by means of numerical methods. Hereby, the part distortion can be predicted, and hence a new HIP-capsule can be designed in such a way to prevent the distortion partly or even completely. In the following, a finite element method is used, on one hand, to simulate part shrinkage during HIP process; on the other hand a method is integrated in this simulation to optimize the HIP-capsule geometry. For the determination of material dependent parameters, a mixture of theoretical and experimental methods is used. Results of simulation are verified for a complex 3d HIP part out of TiAl6V4

  15. Simulation of cold magnetized plasmas with the 3D electromagnetic software CST Microwave Studio®

    Directory of Open Access Journals (Sweden)

    Louche Fabrice

    2017-01-01

    Full Text Available Detailed designs of ICRF antennas were made possible by the development of sophisticated commercial 3D codes like CST Microwave Studio® (MWS. This program allows for very detailed geometries of the radiating structures, but was only considering simple materials like equivalent isotropic dielectrics to simulate the reflection and the refraction of RF waves at the vacuum/plasma interface. The code was nevertheless used intensively, notably for computing the coupling properties of the ITER ICRF antenna. Until recently it was not possible to simulate gyrotropic medias like magnetized plasmas, but recent improvements have allowed programming any material described by a general dielectric or/and diamagnetic tensor. A Visual Basic macro was developed to exploit this feature and was tested for the specific case of a monochromatic plane wave propagating longitudinally with respect to the magnetic field direction. For specific cases the exact solution can be expressed in 1D as the sum of two circularly polarized waves connected by a reflection coefficient that can be analytically computed. Solutions for stratified media can also be derived. This allows for a direct comparison with MWS results. The agreement is excellent but accurate simulations for realistic geometries require large memory resources that could significantly restrict the possibility of simulating cold plasmas to small-scale machines.

  16. AUTOMATIC GENERATION OF ROAD INFRASTRUCTURE IN 3D FOR VEHICLE SIMULATORS

    Directory of Open Access Journals (Sweden)

    Adam Orlický

    2017-12-01

    Full Text Available One of the modern methods of testing new systems and interfaces in vehicles is testing in a vehicle simulator. Providing quality models of virtual scenes is one of tasks for driver-car interaction interface simulation. Nowadays, there exist many programs for creating 3D models of road infrastructures, but most of these programs are very expensive or canÂtt export models for the following use. Therefore, a plug-in has been developed at the Faculty of Transportation Sciences in Prague. It can generate road infrastructure by Czech standard for designing roads (CSN 73 6101. The uniqueness of this plug-in is that it is the first tool for generating road infrastructure in NURBS representation. This type of representation brings more exact models and allows to optimize transfer for creating quality models for vehicle simulators. The scenes created by this plug-in were tested on vehicle simulators. The results have shown that with newly created scenes drivers had a much better feeling in comparison to previous scenes.

  17. Recent progress in 3D EM/EM-PIC simulation with ARGUS and parallel ARGUS

    International Nuclear Information System (INIS)

    Mankofsky, A.; Petillo, J.; Krueger, W.; Mondelli, A.; McNamara, B.; Philp, R.

    1994-01-01

    ARGUS is an integrated, 3-D, volumetric simulation model for systems involving electric and magnetic fields and charged particles, including materials embedded in the simulation region. The code offers the capability to carry out time domain and frequency domain electromagnetic simulations of complex physical systems. ARGUS offers a boolean solid model structure input capability that can include essentially arbitrary structures on the computational domain, and a modular architecture that allows multiple physics packages to access the same data structure and to share common code utilities. Physics modules are in place to compute electrostatic and electromagnetic fields, the normal modes of RF structures, and self-consistent particle-in-cell (PIC) simulation in either a time dependent mode or a steady state mode. The PIC modules include multiple particle species, the Lorentz equations of motion, and algorithms for the creation of particles by emission from material surfaces, injection onto the grid, and ionization. In this paper, we present an updated overview of ARGUS, with particular emphasis given in recent algorithmic and computational advances. These include a completely rewritten frequency domain solver which efficiently treats lossy materials and periodic structures, a parallel version of ARGUS with support for both shared memory parallel vector (i.e. CRAY) machines and distributed memory massively parallel MIMD systems, and numerous new applications of the code

  18. Phast4Windows: A 3D graphical user interface for the reactive-transport simulator PHAST

    Science.gov (United States)

    Charlton, Scott R.; Parkhurst, David L.

    2013-01-01

    Phast4Windows is a Windows® program for developing and running groundwater-flow and reactive-transport models with the PHAST simulator. This graphical user interface allows definition of grid-independent spatial distributions of model properties—the porous media properties, the initial head and chemistry conditions, boundary conditions, and locations of wells, rivers, drains, and accounting zones—and other parameters necessary for a simulation. Spatial data can be defined without reference to a grid by drawing, by point-by-point definitions, or by importing files, including ArcInfo® shape and raster files. All definitions can be inspected, edited, deleted, moved, copied, and switched from hidden to visible through the data tree of the interface. Model features are visualized in the main panel of the interface, so that it is possible to zoom, pan, and rotate features in three dimensions (3D). PHAST simulates single phase, constant density, saturated groundwater flow under confined or unconfined conditions. Reactions among multiple solutes include mineral equilibria, cation exchange, surface complexation, solid solutions, and general kinetic reactions. The interface can be used to develop and run simple or complex models, and is ideal for use in the classroom, for analysis of laboratory column experiments, and for development of field-scale simulations of geochemical processes and contaminant transport.

  19. Simulation of cold magnetized plasmas with the 3D electromagnetic software CST Microwave Studio®

    Science.gov (United States)

    Louche, Fabrice; Křivská, Alena; Messiaen, André; Wauters, Tom

    2017-10-01

    Detailed designs of ICRF antennas were made possible by the development of sophisticated commercial 3D codes like CST Microwave Studio® (MWS). This program allows for very detailed geometries of the radiating structures, but was only considering simple materials like equivalent isotropic dielectrics to simulate the reflection and the refraction of RF waves at the vacuum/plasma interface. The code was nevertheless used intensively, notably for computing the coupling properties of the ITER ICRF antenna. Until recently it was not possible to simulate gyrotropic medias like magnetized plasmas, but recent improvements have allowed programming any material described by a general dielectric or/and diamagnetic tensor. A Visual Basic macro was developed to exploit this feature and was tested for the specific case of a monochromatic plane wave propagating longitudinally with respect to the magnetic field direction. For specific cases the exact solution can be expressed in 1D as the sum of two circularly polarized waves connected by a reflection coefficient that can be analytically computed. Solutions for stratified media can also be derived. This allows for a direct comparison with MWS results. The agreement is excellent but accurate simulations for realistic geometries require large memory resources that could significantly restrict the possibility of simulating cold plasmas to small-scale machines.

  20. Phast4Windows: a 3D graphical user interface for the reactive-transport simulator PHAST.

    Science.gov (United States)

    Charlton, Scott R; Parkhurst, David L

    2013-01-01

    Phast4Windows is a Windows® program for developing and running groundwater-flow and reactive-transport models with the PHAST simulator. This graphical user interface allows definition of grid-independent spatial distributions of model properties-the porous media properties, the initial head and chemistry conditions, boundary conditions, and locations of wells, rivers, drains, and accounting zones-and other parameters necessary for a simulation. Spatial data can be defined without reference to a grid by drawing, by point-by-point definitions, or by importing files, including ArcInfo® shape and raster files. All definitions can be inspected, edited, deleted, moved, copied, and switched from hidden to visible through the data tree of the interface. Model features are visualized in the main panel of the interface, so that it is possible to zoom, pan, and rotate features in three dimensions (3D). PHAST simulates single phase, constant density, saturated groundwater flow under confined or unconfined conditions. Reactions among multiple solutes include mineral equilibria, cation exchange, surface complexation, solid solutions, and general kinetic reactions. The interface can be used to develop and run simple or complex models, and is ideal for use in the classroom, for analysis of laboratory column experiments, and for development of field-scale simulations of geochemical processes and contaminant transport. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

  1. Numerical simulation of a 3-D flow within a storage area hexagonal modular pavement systems

    International Nuclear Information System (INIS)

    Rashid, M A; Abustan, I; Hamzah, M O

    2013-01-01

    This numerical study has been performed to predict the flow patterns and characteristics within a storage area Hexagonal Modular Pavement Systems. Throughout the design and planning period for future construction are increasingly integrating computational fluid dynamics (CFD) into the process. A commercially known software, FLOW-3D, is applied to numerically solve the Navier-stokes equations for solution domains which are separated into three regions with overlapping boundaries to efficiently accommodate the grid resolutions, namely the honeycomb shaped modular, gravel and combined honeycomb shaped modular with gravel fill. The filtration of the fluid within the interstices of a permeable pavement is evaluated by integrating the Reynolds Averaged Navier-Stokes equations (RANS) inside the voids rather than making use of the widespread porous media approach. In conclusion, the results from numerical simulation are generally well agreed with the existing data and flow information such as flow patterns at increased flow, discharge rate and pressure is obtained to be used for engineering design purpose. Overall, the potential for FLOW-3D to model various geometries and configurations appears great. It should be noted that CFD should not be considered a complete replacement for physical modelling; however, it can definitely be used as a supplementary tool throughout the pavement design process.

  2. Planar imaging quantification using 3D attenuation correction data and Monte Carlo simulated buildup factors

    International Nuclear Information System (INIS)

    Miller, C.; Filipow, L.; Jackson, S.; Riauka, T.

    1996-01-01

    A new method to correct for attenuation and the buildup of scatter in planar imaging quantification is presented. The method is based on the combined use of 3D density information provided by computed tomography to correct for attenuation and the application of Monte Carlo simulated buildup factors to correct for buildup in the projection pixels. CT and nuclear medicine images were obtained for a purpose-built nonhomogeneous phantom that models the human anatomy in the thoracic and abdominal regions. The CT transverse slices of the phantom were converted to a set of consecutive density maps. An algorithm was developed that projects the 3D information contained in the set of density maps to create opposing pairs of accurate 2D correction maps that were subsequently applied to planar images acquired from a dual-head gamma camera. A comparison of results obtained by the new method and the geometric mean approach based on published techniques is presented for some of the source arrangements used. Excellent results were obtained for various source - phantom configurations used to evaluate the method. Activity quantification of a line source at most locations in the nonhomogeneous phantom produced errors of less than 2%. Additionally, knowledge of the actual source depth is not required for accurate activity quantification. Quantification of volume sources placed in foam, Perspex and aluminium produced errors of less than 7% for the abdominal and thoracic configurations of the phantom. (author)

  3. Particle simulation of 3D galactic hydrodynamics on the ICL DAP

    International Nuclear Information System (INIS)

    Johns, T.C.; Nelson, A.H.

    1985-01-01

    A non-self-gravitating galactic hydrodynamics code based on a quasi-particle technique and making use of a mesh for force evaluation and sorting purposes is described. The short-range nature of the interparticle pressure forces, coupled with the use of a mesh allows a particularly fast algorithm. The 3D representation of the galaxy is mapped onto the ''3D'' main store of ICL DAP in a natural way, the 2 spatial dimensions in the plane of the galaxy becoming the 2 dimensions of the processor plane on the DAP and the third dimension varying within individual processor storage elements. This leads to a fairly straightforward implementation and a high degree of parallelism in the crucial parts of the code. The particle shuffling which is necessary after each timestep is facilitated by the use of a parallel variant of the bitonic sorting algorithm. Some results of simulations using a 63x63x16 mesh and about 50,000 particles to follow the evolution of a model disk galaxy are presented

  4. Validation of 3-D Ice Accretion Measurement Methodology for Experimental Aerodynamic Simulation

    Science.gov (United States)

    Broeren, Andy P.; Addy, Harold E., Jr.; Lee, Sam; Monastero, Marianne C.

    2015-01-01

    Determining the adverse aerodynamic effects due to ice accretion often relies on dry-air wind-tunnel testing of artificial, or simulated, ice shapes. Recent developments in ice-accretion documentation methods have yielded a laser-scanning capability that can measure highly three-dimensional (3-D) features of ice accreted in icing wind tunnels. The objective of this paper was to evaluate the aerodynamic accuracy of ice-accretion simulations generated from laser-scan data. Ice-accretion tests were conducted in the NASA Icing Research Tunnel using an 18-in. chord, two-dimensional (2-D) straight wing with NACA 23012 airfoil section. For six ice-accretion cases, a 3-D laser scan was performed to document the ice geometry prior to the molding process. Aerodynamic performance testing was conducted at the University of Illinois low-speed wind tunnel at a Reynolds number of 1.8 × 10(exp 6) and a Mach number of 0.18 with an 18-in. chord NACA 23012 airfoil model that was designed to accommodate the artificial ice shapes. The ice-accretion molds were used to fabricate one set of artificial ice shapes from polyurethane castings. The laser-scan data were used to fabricate another set of artificial ice shapes using rapid prototype manufacturing such as stereolithography. The iced-airfoil results with both sets of artificial ice shapes were compared to evaluate the aerodynamic simulation accuracy of the laser-scan data. For five of the six ice-accretion cases, there was excellent agreement in the iced-airfoil aerodynamic performance between the casting and laser-scan based simulations. For example, typical differences in iced-airfoil maximum lift coefficient were less than 3 percent with corresponding differences in stall angle of approximately 1 deg or less. The aerodynamic simulation accuracy reported in this paper has demonstrated the combined accuracy of the laser-scan and rapid-prototype manufacturing approach to simulating ice accretion for a NACA 23012 airfoil. For several

  5. Analysis, Adaptive Control and Adaptive Synchronization of a Nine-Term Novel 3-D Chaotic System with Four Quadratic Nonlinearities and its Circuit Simulation

    Directory of Open Access Journals (Sweden)

    S. Vaidyanathan

    2014-11-01

    Full Text Available This research work describes a nine-term novel 3-D chaotic system with four quadratic nonlinearities and details its qualitative properties. The phase portraits of the 3-D novel chaotic system simulated using MATLAB, depict the strange chaotic attractor of the system. For the parameter values chosen in this work, the Lyapunov exponents of the novel chaotic system are obtained as L1 = 6.8548, L2 = 0 and L3 = −32.8779. Also, the Kaplan-Yorke dimension of the novel chaotic system is obtained as DKY = 2.2085. Next, an adaptive controller is design to achieve global stabilization of the 3-D novel chaotic system with unknown system parameters. Moreover, an adaptive controller is designed to achieve global chaos synchronization of two identical novel chaotic systems with unknown system parameters. Finally, an electronic circuit realization of the novel chaotic system is presented using SPICE to confirm the feasibility of the theoretical model.

  6. 3D Global Coronal Density Structure and Associated Magnetic Field near Solar Maximum

    Energy Technology Data Exchange (ETDEWEB)

    Kramar, Maxim [Physics Department, The Catholic University of America, Washington, DC (United States); Airapetian, Vladimir [Department of Physics and Astronomy, George Mason University, Fairfax, VA (United States); NASA/Goddard Space Flight Center, Code 671, Greenbelt, MD (United States); Lin, Haosheng, E-mail: vladimir.airapetian@nasa.gov [College of Natural Sciences, Institute for Astronomy, University of Hawaii at Manoa, Pukalani, HI (United States)

    2016-08-09

    Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal dynamic phenomena at all scales. We employ STEREO/COR1 data obtained near maximum of solar activity in December 2012 (Carrington rotation, CR 2131) to retrieve and analyze the three-dimensional (3D) coronal electron density in the range of heights from 1.5 to 4 R{sub ⊙} using a tomography method and qualitatively deduce structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in 195 Å band obtained by tomography for the same CR period. We find that the magnetic field configuration during CR 2131 has a tendency to become radially open at heliocentric distances below ~2.5 R{sub ⊙}. We compared the reconstructed 3D coronal structures over the CR near the solar maximum to the one at deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.

  7. 3D Global Coronal Density Structure and Associated Magnetic Field near Solar Maximum

    Directory of Open Access Journals (Sweden)

    Maxim Kramar

    2016-08-01

    Full Text Available Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal dynamic phenomena at all scales. We employ STEREO/COR1 data obtained near maximum of solar activity in December 2012 (Carrington rotation, CR 2131 to retrieve and analyze the three-dimensional (3D coronal electron density in the range of heights from $1.5$ to $4 R_odot$ using a tomography method and qualitatively deduce structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in 195 AA band obtained by tomography for the same CR period. We find that the magnetic field configuration during CR 2131 has a tendency to become radially open at heliocentric distances below $sim 2.5 R_odot$. We compared the reconstructed 3D coronal structures over the CR near the solar maximum to the one at deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.

  8. An Embedded 3D Fracture Modeling Approach for Simulating Fracture-Dominated Fluid Flow and Heat Transfer in Geothermal Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Henry [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wang, Cong [Colorado School of Mines; Winterfeld, Philip [Colorado School of Mines; Wu, Yu-Shu [Colorado School of Mines

    2018-02-14

    An efficient modeling approach is described for incorporating arbitrary 3D, discrete fractures, such as hydraulic fractures or faults, into modeling fracture-dominated fluid flow and heat transfer in fractured geothermal reservoirs. This technique allows 3D discrete fractures to be discretized independently from surrounding rock volume and inserted explicitly into a primary fracture/matrix grid, generated without including 3D discrete fractures in prior. An effective computational algorithm is developed to discretize these 3D discrete fractures and construct local connections between 3D fractures and fracture/matrix grid blocks of representing the surrounding rock volume. The constructed gridding information on 3D fractures is then added to the primary grid. This embedded fracture modeling approach can be directly implemented into a developed geothermal reservoir simulator via the integral finite difference (IFD) method or with TOUGH2 technology This embedded fracture modeling approach is very promising and computationally efficient to handle realistic 3D discrete fractures with complicated geometries, connections, and spatial distributions. Compared with other fracture modeling approaches, it avoids cumbersome 3D unstructured, local refining procedures, and increases computational efficiency by simplifying Jacobian matrix size and sparsity, while keeps sufficient accuracy. Several numeral simulations are present to demonstrate the utility and robustness of the proposed technique. Our numerical experiments show that this approach captures all the key patterns about fluid flow and heat transfer dominated by fractures in these cases. Thus, this approach is readily available to simulation of fractured geothermal reservoirs with both artificial and natural fractures.

  9. Simulation and reconstruction of photon patterns in the PANDA 3D Disc DIRC

    International Nuclear Information System (INIS)

    Merle, O; Düren, M; Föhl, K; Hayrapetyan, A; Koch, P; Kreutzfeldt, K; Kröck, B; Sporleder, M; Stöckmann, N; Zühlsdorf, M

    2012-01-01

    The PANDA Disc DIRC is a novel type of Cherenkov detector, being developed to improve the charged particle identification of the upcoming PANDA experiment at the future FAIR facility. The detector has to cover the endcap region of the target spectrometer, resulting in a geometry that by now has never been applied to a DIRC detector. Additional complications are implied by tight space constraints at the foreseen position, interaction rates of 20 MHz up to 50 MHz and the experiments trigger-less readout scheme. To cope with the lack of experience, the development of detector concepts is driven by the development of computer simulations and dedicated reconstruction methods. The performance analysis of a preceding detector concept, presented at the DIRC workshop in 2009, showed several weaknesses which have been eliminated by revising the detector design. This publication summarizes the current status of the software, the reconstruction method and resulting detector performance of the improved design: the PANDA 3D Disc DIRC.

  10. Simulation Study of Real Time 3-D Synthetic Aperture Sequential Beamforming for Ultrasound Imaging

    DEFF Research Database (Denmark)

    Hemmsen, Martin Christian; Rasmussen, Morten Fischer; Stuart, Matthias Bo

    2014-01-01

    in the main system. The real-time imaging capability is achieved using a synthetic aperture beamforming technique, utilizing the transmit events to generate a set of virtual elements that in combination can generate an image. The two core capabilities in combination is named Synthetic Aperture Sequential......This paper presents a new beamforming method for real-time three-dimensional (3-D) ultrasound imaging using a 2-D matrix transducer. To obtain images with sufficient resolution and contrast, several thousand elements are needed. The proposed method reduces the required channel count from...... Beamforming (SASB). Simulations are performed to evaluate the image quality of the presented method in comparison to Parallel beamforming utilizing 16 receive beamformers. As indicators for image quality the detail resolution and Cystic resolution are determined for a set of scatterers at a depth of 90mm...

  11. GPU-advanced 3D electromagnetic simulations of superconductors in the Ginzburg–Landau formalism

    Energy Technology Data Exchange (ETDEWEB)

    Stošić, Darko; Stošić, Dušan; Ludermir, Teresa [Centro de Informática, Universidade Federal de Pernambuco, Av. Luiz Freire s/n, 50670-901, Recife, PE (Brazil); Stošić, Borko [Departamento de Estatística e Informática, Universidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros s/n, Dois Irmãos, 52171-900 Recife, PE (Brazil); Milošević, Milorad V., E-mail: milorad.milosevic@uantwerpen.be [Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)

    2016-10-01

    Ginzburg–Landau theory is one of the most powerful phenomenological theories in physics, with particular predictive value in superconductivity. The formalism solves coupled nonlinear differential equations for both the electronic and magnetic responsiveness of a given superconductor to external electromagnetic excitations. With order parameter varying on the short scale of the coherence length, and the magnetic field being long-range, the numerical handling of 3D simulations becomes extremely challenging and time-consuming for realistic samples. Here we show precisely how one can employ graphics-processing units (GPUs) for this type of calculations, and obtain physics answers of interest in a reasonable time-frame – with speedup of over 100× compared to best available CPU implementations of the theory on a 256{sup 3} grid.

  12. 3D simulations of axially confined heavy ion beams in round and square pipes

    International Nuclear Information System (INIS)

    Grote, D.P.; Friedman, A.; Haber, I.

    1990-01-01

    We have been using the 3d PIC code WARP6 to model the behavior of beams in a heavy ion induction accelerator; such linacs are candidates for an ICF driver. Improvements have been added to the code to model an axially confined beam using comoving axial electric fields to simulate the confining ''ears'' applied to the accelerating pulses in a real system. We have also added a facility for modeling a beam in a round pipe, applying a capacity matrix to each axial Fourier mode in turn. These additions are described along with results, such as the effect of pipe shape on the beam quality degradation from quadrupole misalignments. 4 refs., 6 figs., 1 tab

  13. 3D simulations of axially confined heavy ion beams in round and square pipes

    International Nuclear Information System (INIS)

    Grote, D.P.; Friedman, A.; Haber, I.

    1991-01-01

    We have been using the 3d PIC code WARP6 to model the behavior of beams in a heavy ion induction accelerator; such linacs are candidates for an ICF driver. Improvements have been added to the code to model an axially confined beam using comoving axial electric fields to simulate the confining ''ears'' applied to the accelerating pulses in a real system. We have also added a facility for modeling a beam in a round pipe, applying a capacity matrix to each axial Fourier mode in turn. These additions are described along with results, such as the effect of pipe shape on the beam quality degradation from quadrupole misalignments. 5 refs., 6 figs., 1 tab

  14. 3D modeling of olive tree and simulating the harvesting forces

    Directory of Open Access Journals (Sweden)

    Glăvan Dan Ovidiu

    2017-01-01

    Full Text Available The paper presents the results of the study regarding the influence of shaking forces on olive tree harvesting systems. Shaking forces can be released through several methods. Important is the end result, namely the shaking force and the cadence of shaking speed. Mechanical and automatic harvesting methods collect more olives than traditional methods but may damage the olive trees. In order to prevent this damage, we need to calculate the necessary shaking force. An original research method is proposed to simulate shaking forces using a 3D olive tree model with Autodesk Inventor software. In the experiments, we use different shaking forces and various shaking speeds. We also use different diameters of the olive tree trunk. We analyze the results from this experiment to determine the optimal shaking force for harvesting olives without damaging the olive tree.

  15. 3D geometric modeling and simulation of laser propagation through turbulence with plenoptic functions

    Science.gov (United States)

    Wu, Chensheng; Nelson, William; Davis, Christopher C.

    2014-10-01

    Plenoptic functions are functions that preserve all the necessary light field information of optical events. Theoretical work has demonstrated that geometric based plenoptic functions can serve equally well in the traditional wave propagation equation known as the "scalar stochastic Helmholtz equation". However, in addressing problems of 3D turbulence simulation, the dominant methods using phase screen models have limitations both in explaining the choice of parameters (on the transverse plane) in real-world measurements, and finding proper correlations between neighboring phase screens (the Markov assumption breaks down). Though possible corrections to phase screen models are still promising, the equivalent geometric approach based on plenoptic functions begins to show some advantages. In fact, in these geometric approaches, a continuous wave problem is reduced to discrete trajectories of rays. This allows for convenience in parallel computing and guarantees conservation of energy. Besides the pairwise independence of simulated rays, the assigned refractive index grids can be directly tested by temperature measurements with tiny thermoprobes combined with other parameters such as humidity level and wind speed. Furthermore, without loss of generality one can break the causal chain in phase screen models by defining regional refractive centers to allow rays that are less affected to propagate through directly. As a result, our work shows that the 3D geometric approach serves as an efficient and accurate method in assessing relevant turbulence problems with inputs of several environmental measurements and reasonable guesses (such as Cn 2 levels). This approach will facilitate analysis and possible corrections in lateral wave propagation problems, such as image de-blurring, prediction of laser propagation over long ranges, and improvement of free space optic communication systems. In this paper, the plenoptic function model and relevant parallel algorithm computing

  16. Curvilinear immersed boundary method for simulating fluid structure interaction with complex 3D rigid bodies

    Science.gov (United States)

    Borazjani, Iman; Ge, Liang; Sotiropoulos, Fotis

    2008-08-01

    The sharp-interface CURVIB approach of Ge and Sotiropoulos [L. Ge, F. Sotiropoulos, A numerical method for solving the 3D unsteady incompressible Navier-Stokes equations in curvilinear domains with complex immersed boundaries, Journal of Computational Physics 225 (2007) 1782-1809] is extended to simulate fluid structure interaction (FSI) problems involving complex 3D rigid bodies undergoing large structural displacements. The FSI solver adopts the partitioned FSI solution approach and both loose and strong coupling strategies are implemented. The interfaces between immersed bodies and the fluid are discretized with a Lagrangian grid and tracked with an explicit front-tracking approach. An efficient ray-tracing algorithm is developed to quickly identify the relationship between the background grid and the moving bodies. Numerical experiments are carried out for two FSI problems: vortex induced vibration of elastically mounted cylinders and flow through a bileaflet mechanical heart valve at physiologic conditions. For both cases the computed results are in excellent agreement with benchmark simulations and experimental measurements. The numerical experiments suggest that both the properties of the structure (mass, geometry) and the local flow conditions can play an important role in determining the stability of the FSI algorithm. Under certain conditions the FSI algorithm is unconditionally unstable even when strong coupling FSI is employed. For such cases, however, combining the strong coupling iteration with under-relaxation in conjunction with the Aitken's acceleration technique is shown to effectively resolve the stability problems. A theoretical analysis is presented to explain the findings of the numerical experiments. It is shown that the ratio of the added mass to the mass of the structure as well as the sign of the local time rate of change of the force or moment imparted on the structure by the fluid determine the stability and convergence of the FSI

  17. 3-D dynamic rupture simulations of the 2016 Kumamoto, Japan, earthquake

    Science.gov (United States)

    Urata, Yumi; Yoshida, Keisuke; Fukuyama, Eiichi; Kubo, Hisahiko

    2017-11-01

    Using 3-D dynamic rupture simulations, we investigated the 2016 Mw7.1 Kumamoto, Japan, earthquake to elucidate why and how the rupture of the main shock propagated successfully, assuming a complicated fault geometry estimated on the basis of the distributions of the aftershocks. The Mw7.1 main shock occurred along the Futagawa and Hinagu faults. Within 28 h before the main shock, three M6-class foreshocks occurred. Their hypocenters were located along the Hinagu and Futagawa faults, and their focal mechanisms were similar to that of the main shock. Therefore, an extensive stress shadow should have been generated on the fault plane of the main shock. First, we estimated the geometry of the fault planes of the three foreshocks as well as that of the main shock based on the temporal evolution of the relocated aftershock hypocenters. We then evaluated the static stress changes on the main shock fault plane that were due to the occurrence of the three foreshocks, assuming elliptical cracks with constant stress drops on the estimated fault planes. The obtained static stress change distribution indicated that Coulomb failure stress change (ΔCFS) was positive just below the hypocenter of the main shock, while the ΔCFS in the shallow region above the hypocenter was negative. Therefore, these foreshocks could encourage the initiation of the main shock rupture and could hinder the propagation of the rupture toward the shallow region. Finally, we conducted 3-D dynamic rupture simulations of the main shock using the initial stress distribution, which was the sum of the static stress changes caused by these foreshocks and the regional stress field. Assuming a slip-weakening law with uniform friction parameters, we computed 3-D dynamic rupture by varying the friction parameters and the values of the principal stresses. We obtained feasible parameter ranges that could reproduce the characteristic features of the main shock rupture revealed by seismic waveform analyses. We also

  18. Plane shear flows of frictionless spheres: Kinetic theory and 3D soft-sphere discrete element method simulations

    OpenAIRE

    Vescovi, Dalila; Berzi, Diego; Richard, Patrick; Brodu, Nicolas

    2014-01-01

    International audience; We use existing 3D Discrete Element simulations of simple shear flows of spheres to evaluate the radial distribution function at contact that enables kinetic theory to correctly predict the pressure and the shear stress, for different values of the collisional coefficient of restitution. Then, we perform 3D Discrete Element simulations of plane flows of frictionless, inelastic spheres, sheared between walls made bumpy by gluing particles in a regular array, at fixed av...

  19. Global atmospheric budget of acetaldehyde: 3-D model analysis and constraints from in-situ and satellite observations

    Directory of Open Access Journals (Sweden)

    D. B. Millet

    2010-04-01

    Full Text Available We construct a global atmospheric budget for acetaldehyde using a 3-D model of atmospheric chemistry (GEOS-Chem, and use an ensemble of observations to evaluate present understanding of its sources and sinks. Hydrocarbon oxidation provides the largest acetaldehyde source in the model (128 Tg a−1, a factor of 4 greater than the previous estimate, with alkanes, alkenes, and ethanol the main precursors. There is also a minor source from isoprene oxidation. We use an updated chemical mechanism for GEOS-Chem, and photochemical acetaldehyde yields are consistent with the Master Chemical Mechanism. We present a new approach to quantifying the acetaldehyde air-sea flux based on the global distribution of light absorption due to colored dissolved organic matter (CDOM derived from satellite ocean color observations. The resulting net ocean emission is 57 Tg a−1, the second largest global source of acetaldehyde. A key uncertainty is the acetaldehyde turnover time in the ocean mixed layer, with quantitative model evaluation over the ocean complicated by known measurement artifacts in clean air. Simulated concentrations in surface air over the ocean generally agree well with aircraft measurements, though the model tends to overestimate the vertical gradient. PAN:NOx ratios are well-simulated in the marine boundary layer, providing some support for the modeled ocean source. We introduce the Model of Emissions of Gases and Aerosols from Nature (MEGANv2.1 for acetaldehyde and ethanol and use it to quantify their net flux from living terrestrial plants. Including emissions from decaying plants the total direct acetaldehyde source from the land biosphere is 23 Tg a−1. Other terrestrial acetaldehyde sources include biomass burning (3 Tg a−1 and anthropogenic emissions (2 Tg a−1. Simulated concentrations in the continental boundary layer are generally unbiased and capture the spatial

  20. Realistic 3D Terrain Roaming and Real-Time Flight Simulation

    Science.gov (United States)

    Que, Xiang; Liu, Gang; He, Zhenwen; Qi, Guang

    2014-12-01

    This paper presents an integrate method, which can provide access to current status and the dynamic visible scanning topography, to enhance the interactive during the terrain roaming and real-time flight simulation. A digital elevation model and digital ortho-photo map data integrated algorithm is proposed as the base algorithm for our approach to build a realistic 3D terrain scene. A new technique with help of render to texture and head of display for generating the navigation pane is used. In the flight simulating, in order to eliminate flying "jump", we employs the multidimensional linear interpolation method to adjust the camera parameters dynamically and steadily. Meanwhile, based on the principle of scanning laser imaging, we draw pseudo color figures by scanning topography in different directions according to the real-time flying status. Simulation results demonstrate that the proposed algorithm is prospective for applications and the method can improve the effect and enhance dynamic interaction during the real-time flight.

  1. 3D electromagnetic simulation of spatial autoresonance acceleration of electron beams

    International Nuclear Information System (INIS)

    Dugar-Zhabon, V D; Orozco, E A; González, J D

    2016-01-01

    The results of full electromagnetic simulations of the electron beam acceleration by a TE 112 linear polarized electromagnetic field through Space Autoresonance Acceleration mechanism are presented. In the simulations, both the self-sustaned electric field and selfsustained magnetic field produced by the beam electrons are included into the elaborated 3D Particle in Cell code. In this system, the space profile of the magnetostatic field maintains the electron beams in the acceleration regime along their trajectories. The beam current density evolution is calculated applying the charge conservation method. The full magnetic field in the superparticle positions is found by employing the trilinear interpolation of the mesh node data. The relativistic Newton-Lorentz equation presented in the centered finite difference form is solved using the Boris algorithm that provides visualization of the beam electrons pathway and energy evolution. A comparison between the data obtained from the full electromagnetic simulations and the results derived from the motion equation depicted in an electrostatic approximation is carried out. It is found that the self-sustained magnetic field is a factor which improves the resonance phase conditions and reduces the beam energy spread. (paper)

  2. 3D nonlinear numerical simulation of the current-convective instability in detached diverter plasma

    Science.gov (United States)

    Stepanenko, Alexander; Krasheninnikov, Sergei

    2017-10-01

    One of the possible mechanisms responsible for strong radiation fluctuations observed in the recent experiments with detached plasmas at ASDEX Upgrade [Potzel et al., Nuclear Fusion, 2014] can be related to the onset of the current-convective instability (CCI) driven by strong asymmetry of detachment in the inner and outer tokamak divertors [Krasheninnikov and Smolyakov, PoP, 2016]. In this study we present the first results of 3D nonlinear numerical simulations of the CCI in divertor plasma for the conditions relevant to the AUG experiment. The general physical model used to simulate the CCI, qualitative estimates for the instability characteristic growth rate and transverse wavelengths derived for plasma, which is spatially inhomogeneous both across and along the magnetic field lines, are presented. The simulation results, demonstrating nonlinear dynamics of the CCI, provide the frequency spectra of turbulent divertor plasma fluctuations showing good agreement with the available experimental data. This material is based upon the work supported by the U.S. Department of Energy under Award No. DE-FG02-04ER54739 at UCSD and by the Russian Ministry of Education and Science Grant No. 14.Y26.31.0008 at MEPhI.

  3. A novel 3D-printed hybrid simulation model for robotic-assisted kidney transplantation (RAKT).

    Science.gov (United States)

    Uwechue, Raphael; Gogalniceanu, Petrut; Kessaris, Nicos; Byrne, Nick; Chandak, Pankaj; Olsburgh, Jonathon; Ahmed, Kamran; Mamode, Nizam; Loukopoulos, Ioannis

    2018-01-27

    Robotic-assisted kidney transplantation (RAKT) offers key benefits for patients that have been demonstrated in several studies. A barrier to the wider uptake of RAKT is surgical skill acquisition. This is exacerbated by the challenges of modern surgery with reduced surgical training time, patient safety concerns and financial pressures. Simulation is a well-established method of developing surgical skill in a safe and controlled environment away from the patient. We have developed a 3D printed simulation model for the key step of the kidney transplant operation which is the vascular anastomosis. The model is anatomically accurate, based on the CT scans of patients and it incorporates deceased donor vascular tissue. Crucially, it was developed to be used in the robotic operating theatre with the operating robot to enhance its fidelity. It is portable and relatively inexpensive when compared with other forms of simulation such as virtual reality or animal lab training. It thus has the potential of being more accessible as a training tool for the safe acquisition of RAKT specific skills. We demonstrate this model here.

  4. Real-Time Climate Simulations in the Interactive 3D Game Universe Sandbox ²

    Science.gov (United States)

    Goldenson, N. L.

    2014-12-01

    Exploration in an open-ended computer game is an engaging way to explore climate and climate change. Everyone can explore physical models with real-time visualization in the educational simulator Universe Sandbox ² (universesandbox.com/2), which includes basic climate simulations on planets. I have implemented a time-dependent, one-dimensional meridional heat transport energy balance model to run and be adjustable in real time in the midst of a larger simulated system. Universe Sandbox ² is based on the original game - at its core a gravity simulator - with other new physically-based content for stellar evolution, and handling collisions between bodies. Existing users are mostly science enthusiasts in informal settings. We believe that this is the first climate simulation to be implemented in a professionally developed computer game with modern 3D graphical output in real time. The type of simple climate model we've adopted helps us depict the seasonal cycle and the more drastic changes that come from changing the orbit or other external forcings. Users can alter the climate as the simulation is running by altering the star(s) in the simulation, dragging to change orbits and obliquity, adjusting the climate simulation parameters directly or changing other properties like CO2 concentration that affect the model parameters in representative ways. Ongoing visuals of the expansion and contraction of sea ice and snow-cover respond to the temperature calculations, and make it accessible to explore a variety of scenarios and intuitive to understand the output. Variables like temperature can also be graphed in real time. We balance computational constraints with the ability to capture the physical phenomena we wish to visualize, giving everyone access to a simple open-ended meridional energy balance climate simulation to explore and experiment with. The software lends itself to labs at a variety of levels about climate concepts including seasons, the Greenhouse effect

  5. 3D Staggered-Grid Finite-Difference Simulation of Acoustic Waves in Turbulent Moving Media

    Science.gov (United States)

    Symons, N. P.; Aldridge, D. F.; Marlin, D.; Wilson, D. K.; Sullivan, P.; Ostashev, V.

    2003-12-01

    Acoustic wave propagation in a three-dimensional heterogeneous moving atmosphere is accurately simulated with a numerical algorithm recently developed under the DOD Common High Performance Computing Software Support Initiative (CHSSI). Sound waves within such a dynamic environment are mathematically described by a set of four, coupled, first-order partial differential equations governing small-amplitude fluctuations in pressure and particle velocity. The system is rigorously derived from fundamental principles of continuum mechanics, ideal-fluid constitutive relations, and reasonable assumptions that the ambient atmospheric motion is adiabatic and divergence-free. An explicit, time-domain, finite-difference (FD) numerical scheme is used to solve the system for both pressure and particle velocity wavefields. The atmosphere is characterized by 3D gridded models of sound speed, mass density, and the three components of the wind velocity vector. Dependent variables are stored on staggered spatial and temporal grids, and centered FD operators possess 2nd-order and 4th-order space/time accuracy. Accurate sound wave simulation is achieved provided grid intervals are chosen appropriately. The gridding must be fine enough to reduce numerical dispersion artifacts to an acceptable level and maintain stability. The algorithm is designed to execute on parallel computational platforms by utilizing a spatial domain-decomposition strategy. Currently, the algorithm has been validated on four different computational platforms, and parallel scalability of approximately 85% has been demonstrated. Comparisons with analytic solutions for uniform and vertically stratified wind models indicate that the FD algorithm generates accurate results with either a vanishing pressure or vanishing vertical-particle velocity boundary condition. Simulations are performed using a kinematic turbulence wind profile developed with the quasi-wavelet method. In addition, preliminary results are presented

  6. PhysiCell: An open source physics-based cell simulator for 3-D multicellular systems.

    Science.gov (United States)

    Ghaffarizadeh, Ahmadreza; Heiland, Randy; Friedman, Samuel H; Mumenthaler, Shannon M; Macklin, Paul

    2018-02-01

    Many multicellular systems problems can only be understood by studying how cells move, grow, divide, interact, and die. Tissue-scale dynamics emerge from systems of many interacting cells as they respond to and influence their microenvironment. The ideal "virtual laboratory" for such multicellular systems simulates both the biochemical microenvironment (the "stage") and many mechanically and biochemically interacting cells (the "players" upon the stage). PhysiCell-physics-based multicellular simulator-is an open source agent-based simulator that provides both the stage and the players for studying many interacting cells in dynamic tissue microenvironments. It builds upon a multi-substrate biotransport solver to link cell phenotype to multiple diffusing substrates and signaling factors. It includes biologically-driven sub-models for cell cycling, apoptosis, necrosis, solid and fluid volume changes, mechanics, and motility "out of the box." The C++ code has minimal dependencies, making it simple to maintain and deploy across platforms. PhysiCell has been parallelized with OpenMP, and its performance scales linearly with the number of cells. Simulations up to 105-106 cells are feasible on quad-core desktop workstations; larger simulations are attainable on single HPC compute nodes. We demonstrate PhysiCell by simulating the impact of necrotic core biomechanics, 3-D geometry, and stochasticity on the dynamics of hanging drop tumor spheroids and ductal carcinoma in situ (DCIS) of the breast. We demonstrate stochastic motility, chemical and contact-based interaction of multiple cell types, and the extensibility of PhysiCell with examples in synthetic multicellular systems (a "cellular cargo delivery" system, with application to anti-cancer treatments), cancer heterogeneity, and cancer immunology. PhysiCell is a powerful multicellular systems simulator that will be continually improved with new capabilities and performance improvements. It also represents a significant

  7. The early phases of galaxy clusters formation in IR: coupling hydrodynamical simulations with GRASIL-3D

    Science.gov (United States)

    Granato, Gian Luigi; Ragone-Figueroa, Cinthia; Domínguez-Tenreiro, Rosa; Obreja, Aura; Borgani, Stefano; De Lucia, Gabriella; Murante, Giuseppe

    2015-06-01

    We compute and study the infrared and sub-mm properties of high-redshift (z ≳ 1) simulated clusters and protoclusters. The results of a large set of hydrodynamical zoom-in simulations including active galactic nuclei (AGN) feedback, have been treated with the recently developed radiative transfer code GRASIL-3D, which accounts for the effect of dust reprocessing in an arbitrary geometry. Here, we have slightly generalized the code to adapt it to the present purpose. Then we have post-processed boxes of physical size 2 Mpc encompassing each of the 24 most massive clusters identified at z = 0, at several redshifts between 0.5 and 3, producing IR and sub-mm mock images of these regions and spectral energy distributions (SEDs) of the radiation coming out from them. While this field is in its infancy from the observational point of view, rapid development is expected in the near future thanks to observations performed in the far-IR and sub-mm bands. Notably, we find that in this spectral regime our prediction are little affected by the assumption required by this post-processing, and the emission is mostly powered by star formation (SF) rather than accretion on to super massive black hole (SMBH). The comparison with the little observational information currently available, highlights that the simulated cluster regions never attain the impressive star formation rates suggested by these observations. This problem becomes more intriguing taking into account that the brightest cluster galaxies (BCGs) in the same simulations turn out to be too massive. It seems that the interplay between the feedback schemes and the star formation model should be revised, possibly incorporating a positive feedback mode.

  8. 3D design and electric simulation of a silicon drift detector using a spiral biasing adapter

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yu-yun; Xiong, Bo [School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 (China); Center for Semiconductor Particle and photon Imaging Detector, Development and Fabrication, Xiangtan University, Xiangtan 411105 (China); Li, Zheng, E-mail: zhengli58@gmail.com [School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 (China); Center for Semiconductor Particle and photon Imaging Detector, Development and Fabrication, Xiangtan University, Xiangtan 411105 (China)

    2016-09-21

    The detector system of combining a spiral biasing adapter (SBA) with a silicon drift detector (SBA-SDD) is largely different from the traditional silicon drift detector (SDD), including the spiral SDD. It has a spiral biasing adapter of the same design as a traditional spiral SDD and an SDD with concentric rings having the same radius. Compared with the traditional spiral SDD, the SBA-SDD separates the spiral's functions of biasing adapter and the p–n junction definition. In this paper, the SBA-SDD is simulated using a Sentaurus TCAD tool, which is a full 3D device simulation tool. The simulated electric characteristics include electric potential, electric field, electron concentration, and single event effect. Because of the special design of the SBA-SDD, the SBA can generate an optimum drift electric field in the SDD, comparable with the conventional spiral SDD, while the SDD can be designed with concentric rings to reduce surface area. Also the current and heat generated in the SBA are separated from the SDD. To study the single event response, we simulated the induced current caused by incident heavy ions (20 and 50 μm penetration length) with different linear energy transfer (LET). The SBA-SDD can be used just like a conventional SDD, such as X-ray detector for energy spectroscopy and imaging, etc. - Highlights: • The separation of the spiral biasing adapter and SDD is a new concept. • The distribution of the electric potential is symmetrical around the axis through the anode. • The region with higher electron concentrations defines the drift channel.

  9. Impact of helical boundary conditions on nonlinear 3D magnetohydrodynamic simulations of reversed-field pinch

    International Nuclear Information System (INIS)

    Veranda, M; Bonfiglio, D; Cappello, S; Chacón, L; Escande, D F

    2013-01-01

    Helical self-organized reversed-field pinch (RFP) regimes emerge both numerically—in 3D visco-resistive magnetohydrodynamic (MHD) simulations—and experimentally, as in the RFX-mod device at high current (I P above 1 MA). These states, called quasi-single helicity (QSH) states, are characterized by the action of a MHD mode that impresses a quasi-helical symmetry to the system, thus allowing a high degree of magnetic chaos healing. This is in contrast with the multiple helicity (MH) states, where magnetic fluctuations create a chaotic magnetic field degrading the confinement properties of the RFP. This paper reports an extensive numerical study performed in the frame of 3D visco-resistive MHD which considers the effect of helical magnetic boundary conditions, i.e. of a finite value of the radial magnetic field at the edge (magnetic perturbation, MP). We show that the system can be driven to a selected QSH state starting from both spontaneous QSH and MH regimes. In particular, a high enough MP can force a QSH helical self-organization with a helicity different from the spontaneous one. Moreover, MH states can be turned into QSH states with a selected helicity. A threshold in the amplitude of MP is observed above which is able to influence the system. Analysis of the magnetic topology of these simulations indicates that the dominant helical mode is able to temporarily sustain conserved magnetic structures in the core of the plasma. The region occupied by conserved magnetic surfaces increases reducing secondary modes' amplitude to experimental-like values. (paper)

  10. 3D nonlinear MHD simulations of ultra-low q plasmas

    International Nuclear Information System (INIS)

    Bonfiglio, D.; Cappello, S.; Piovan, R.; Zanotto, L.; Zuin, M.

    2008-01-01

    Magnetohydrodynamic (MHD) phenomena occurring in the ultra-low safety factor (ULq) configuration are investigated by means of 3D nonlinear MHD simulations. The ULq configuration, a screw pinch characterized by the edge safety factor q edge in the interval 0 edge edge values which are about the major rational numbers, suggesting plasma self-organization. Similar behaviour is observed in experimental ULq discharges, like those recently obtained exploiting the flexibility of the RFX-mod device. The transition of q edge from a major rational number to the next one occurs together with the development of a kink deformation of the plasma column, whose stabilization yields a nearly axisymmetric state with a rather flat q profile. Numerical simulations also show that it is possible to sustain either of the two conditions, namely, the saturated kink helical configuration and the axisymmetric one, by forcing q edge at a suitable value. Finally, the effects of this MHD phenomenology on the confinement properties of ULq plasmas are discussed.

  11. Simulation of diode electron source of PSTA latex EBM using OPERA-3D software

    International Nuclear Information System (INIS)

    Taufik; Darsono

    2014-01-01

    Electron beam transport from E-gun to the atmospheres in EBM is determined by main parameters of beam transports such as E-gun, accelerator tube, beam optics (focusing and scanning magnets). In principle the beam transport will optimum if the electron beam travels in axial axes of accelerator tubes, and the beam optics works properly. The EBM E-gun structure of PSTA uses diode type with Pierce cathode where beam transport yield will be affected by electrode voltage of the accelerator tube. To answer above hypothesis the E-gun and accelerator tube will be simulated by making a model used accelerator software programme which is called OPERA-3D. Beam transport parameters, such as distance between cathode and anode of E-gun, accelerator electrode HV, and the symmetry of cathode Pierce E-gun with anode electrode of accelerator tube, will be investigated their impacts to direction and shape of beam transports. The simulation results shows that the three parameters affects to the direction and shape of the beam transport. Diode type of electron gun cannot result parallel electron beam, but the best beam transport of this type electron gun are obtained at the accelerator voltage 300 kV, and the distance between cathode and anode of E-gun 6.1 mm where they are in the symmetry condition. (author)

  12. 3D multiphysics modeling of superconducting cavities with a massively parallel simulation suite

    Directory of Open Access Journals (Sweden)

    Oleksiy Kononenko

    2017-10-01

    Full Text Available Radiofrequency cavities based on superconducting technology are widely used in particle accelerators for various applications. The cavities usually have high quality factors and hence narrow bandwidths, so the field stability is sensitive to detuning from the Lorentz force and external loads, including vibrations and helium pressure variations. If not properly controlled, the detuning can result in a serious performance degradation of a superconducting accelerator, so an understanding of the underlying detuning mechanisms can be very helpful. Recent advances in the simulation suite ace3p have enabled realistic multiphysics characterization of such complex accelerator systems on supercomputers. In this paper, we present the new capabilities in ace3p for large-scale 3D multiphysics modeling of superconducting cavities, in particular, a parallel eigensolver for determining mechanical resonances, a parallel harmonic response solver to calculate the response of a cavity to external vibrations, and a numerical procedure to decompose mechanical loads, such as from the Lorentz force or piezoactuators, into the corresponding mechanical modes. These capabilities have been used to do an extensive rf-mechanical analysis of dressed TESLA-type superconducting cavities. The simulation results and their implications for the operational stability of the Linac Coherent Light Source-II are discussed.

  13. 3D Orthorhombic Elastic Wave Propagation Pre-Test Simulation of SPE DAG-1 Test

    Science.gov (United States)

    Jensen, R. P.; Preston, L. A.

    2017-12-01

    A more realistic representation of many geologic media can be characterized as a dense system of vertically-aligned microfractures superimposed on a finely-layered horizontal geology found in shallow crustal rocks. This seismic anisotropy representation lends itself to being modeled as an orthorhombic elastic medium comprising three mutually orthogonal symmetry planes containing nine independent moduli. These moduli can be determined by observing (or prescribing) nine independent P-wave and S-wave phase speeds along different propagation directions. We have developed an explicit time-domain finite-difference (FD) algorithm for simulating 3D elastic wave propagation in a heterogeneous orthorhombic medium. The components of the particle velocity vector and the stress tensor are governed by a set of nine, coupled, first-order, linear, partial differential equations (PDEs) called the velocity-stress system. All time and space derivatives are discretized with centered and staggered FD operators possessing second- and fourth-order numerical accuracy, respectively. Additionally, we have implemented novel perfectly matched layer (PML) absorbing boundary conditions, specifically designed for orthorhombic media, to effectively suppress grid boundary reflections. In support of the Source Physics Experiment (SPE) Phase II, a series of underground chemical explosions at the Nevada National Security Site, the code has been used to perform pre-test estimates of the Dry Alluvium Geology - Experiment 1 (DAG-1). Based on literature searches, realistic geologic structure and values for orthorhombic P-wave and S-wave speeds have been estimated. Results and predictions from the simulations are presented.

  14. Multigrid direct numerical simulation of the whole process of flow transition in 3-D boundary layers

    Science.gov (United States)

    Liu, Chaoqun; Liu, Zhining

    1993-01-01

    A new technology was developed in this study which provides a successful numerical simulation of the whole process of flow transition in 3-D boundary layers, including linear growth, secondary instability, breakdown, and transition at relatively low CPU cost. Most other spatial numerical simulations require high CPU cost and blow up at the stage of flow breakdown. A fourth-order finite difference scheme on stretched and staggered grids, a fully implicit time marching technique, a semi-coarsening multigrid based on the so-called approximate line-box relaxation, and a buffer domain for the outflow boundary conditions were all used for high-order accuracy, good stability, and fast convergence. A new fine-coarse-fine grid mapping technique was developed to keep the code running after the laminar flow breaks down. The computational results are in good agreement with linear stability theory, secondary instability theory, and some experiments. The cost for a typical case with 162 x 34 x 34 grid is around 2 CRAY-YMP CPU hours for 10 T-S periods.

  15. Pelton turbine Needle erosion prediction based on 3D three- phase flow simulation

    International Nuclear Information System (INIS)

    Chongji, Z; Yexiang, X; Wei, Z; Yangyang, Y; Lei, C; Zhengwei, W

    2014-01-01

    Pelton turbine, which applied to the high water head and small flow rate, is widely used in the mountainous area. During the operation period the sediment contained in the water does not only induce the abrasion of the buckets, but also leads to the erosion at the nozzle which may damage the needle structure. The nozzle and needle structure are mainly used to form high quality cylindrical jet and increase the efficiency of energy exchange in the runner to the most. Thus the needle erosion will lead to the deformation of jet, and then may cause the efficiency loss and cavitation. The favourable prediction of abrasion characteristic of needle can effectively guide the optimization design and maintenance of needle structure. This paper simulated the unsteady three-dimensional multi-phase flow in the nozzle and injected jet flow. As the jet containing water and sediment is injected into the free atmosphere air with high velocity, the VOF model was adopted to predict the water and air flow. The sediment is simplified into round solid particle and the discrete particle model (DPM) was employed to predict the needle abrasion characteristic. The sand particle tracks were analyzed to interpret the mechanism of sand erosion on the needle surface. And the numerical result of needle abrasion was obtained and compared with the abrasion field observation. The similarity of abrasion pattern between the numerical results and field observation illustrated the validity of the 3D multi-phase flow simulation method

  16. Pelton turbine Needle erosion prediction based on 3D three- phase flow simulation

    Science.gov (United States)

    Chongji, Z.; Yexiang, X.; Wei, Z.; Yangyang, Y.; Lei, C.; Zhengwei, W.

    2014-03-01

    Pelton turbine, which applied to the high water head and small flow rate, is widely used in the mountainous area. During the operation period the sediment contained in the water does not only induce the abrasion of the buckets, but also leads to the erosion at the nozzle which may damage the needle structure. The nozzle and needle structure are mainly used to form high quality cylindrical jet and increase the efficiency of energy exchange in the runner to the most. Thus the needle erosion will lead to the deformation of jet, and then may cause the efficiency loss and cavitation. The favourable prediction of abrasion characteristic of needle can effectively guide the optimization design and maintenance of needle structure. This paper simulated the unsteady three-dimensional multi-phase flow in the nozzle and injected jet flow. As the jet containing water and sediment is injected into the free atmosphere air with high velocity, the VOF model was adopted to predict the water and air flow. The sediment is simplified into round solid particle and the discrete particle model (DPM) was employed to predict the needle abrasion characteristic. The sand particle tracks were analyzed to interpret the mechanism of sand erosion on the needle surface. And the numerical result of needle abrasion was obtained and compared with the abrasion field observation. The similarity of abrasion pattern between the numerical results and field observation illustrated the validity of the 3D multi-phase flow simulation method.

  17. Comparison of plasma data from ASPERA-3/Mars-Express with a 3-D hybrid simulation

    Directory of Open Access Journals (Sweden)

    A. Bößwetter

    2007-08-01

    Full Text Available The ELS and IMA sensors of the ASPERA-3 experiment onboard of Mars-Express (MEX can measure electron as well as ion moments. We compare these measurements for a specific orbit with the simulation results from a 3-D hybrid model. In the hybrid approximation the electrons are modeled as a massless charge-neutralizing fluid, whereas the ions are treated as individual particles. This approach allows gyroradius effects to be included in our model calculations of the Martian plasma environment because the gyroradii of the solar wind protons are in the range of several hundred kilometers and therefore comparable with the characteristic scales of the subsolar ionospheric interaction region. The position of both the bow shock and the Ion Composition Boundary (ICB manifest in the MEX data as well as in the results from the hybrid simulation nearly at the same location. The characteristic features of these boundaries, i.e. an increase of proton density and temperature at the Bow Shock and a transition from solar wind to ionospheric particles at the ICB, are clearly identifiable in the data.

  18. Development of a self-consistent lightning NOx simulation in large-scale 3-D models

    Science.gov (United States)

    Luo, Chao; Wang, Yuhang; Koshak, William J.

    2017-03-01

    We seek to develop a self-consistent representation of lightning NOx (LNOx) simulation in a large-scale 3-D model. Lightning flash rates are parameterized functions of meteorological variables related to convection. We examine a suite of such variables and find that convective available potential energy and cloud top height give the best estimates compared to July 2010 observations from ground-based lightning observation networks. Previous models often use lightning NOx vertical profiles derived from cloud-resolving model simulations. An implicit assumption of such an approach is that the postconvection lightning NOx vertical distribution is the same for all deep convection, regardless of geographic location, time of year, or meteorological environment. Detailed observations of the lightning channel segment altitude distribution derived from the NASA Lightning Nitrogen Oxides Model can be used to obtain the LNOx emission profile. Coupling such a profile with model convective transport leads to a more self-consistent lightning distribution compared to using prescribed postconvection profiles. We find that convective redistribution appears to be a more important factor than preconvection LNOx profile selection, providing another reason for linking the strength of convective transport to LNOx distribution.

  19. The use of CAFE-3D for the simulation of tunnel fires

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, C.; Koski, J.A.; Hohnstreiter, G.F.; Khalil, I. [Sandia National Labs., Albuquerque, NM (United States); Suo-Anttila, A. [Alion Science and Technology, Albuquerque, NM (United States)

    2004-07-01

    Fires after accidents inside tunnels, such as the July 2001 Howard Street Tunnel fire in Baltimore, Maryland, USA, have raised stakeholder questions concerning the survivability of a spent nuclear fuel (SNF) transport cask when exposed to similar thermal environments. The analysis of tunnel fires is a computational challenge because of the need for very large computational domains in order to fully simulate such a problem. In this paper, the analyses of two different tunnel fire scenarios are described and the performance of typical SNF casks when exposed to these tunnel fire environments is discussed. The CAFE-3D fire code is used to model a series of fires inside tunnels, and the thermal performance of a SNF transportation cask within such fire environments is estimated with the use of the MSC PATRAN-P/Thermal finite element analysis code. The methodology used to simulate this type of fire scenario as well as a description of the manner in which the CAFE code couples the computational fluid dynamics and the finite element analysis techniques are also presented.

  20. Simulation of a 3D MOT-Optical Molasses Hybrid for Potassium-41 Atoms

    Science.gov (United States)

    Peterson, W. A.; Wrubel, Jonathan

    2017-04-01

    We report a design and numerical model for a 3D magneto-optical trap (MOT)-optical molasses hybrid for potassium-41 atoms. In this arrangement, the usual quadrupole magnetic field is replaced by an octupole field. The octupole field has a central region of very low magnetic field where our simulations show that the atoms experience an optical molasses, resulting in sub-doppler cooling not possible in a quadrupole MOT. The simulations also show that the presence of the magneto-optical trapping force at the edge of the cooling beams provides a restoring force which cycles atoms through the molasses region. We plan to use this hybrid trap to directly load a far off-resonance optical dipole trap. Because the atoms are recycled for multiple passes through the molasses, we expect a higher phase-space density of atoms loaded into the dipole trap. Similar hybrid cooling schemes should be relevant for lithium-6 and lithium-7, which also have poorly resolved D2 hyperfine structure. Research Corporation for Science Advancement, Cottrell College Science Award.

  1. The use of CAFE-3D for the simulation of tunnel fires

    International Nuclear Information System (INIS)

    Lopez, C.; Koski, J.A.; Hohnstreiter, G.F.; Khalil, I.; Suo-Anttila, A.

    2004-01-01

    Fires after accidents inside tunnels, such as the July 2001 Howard Street Tunnel fire in Baltimore, Maryland, USA, have raised stakeholder questions concerning the survivability of a spent nuclear fuel (SNF) transport cask when exposed to similar thermal environments. The analysis of tunnel fires is a computational challenge because of the need for very large computational domains in order to fully simulate such a problem. In this paper, the analyses of two different tunnel fire scenarios are described and the performance of typical SNF casks when exposed to these tunnel fire environments is discussed. The CAFE-3D fire code is used to model a series of fires inside tunnels, and the thermal performance of a SNF transportation cask within such fire environments is estimated with the use of the MSC PATRAN-P/Thermal finite element analysis code. The methodology used to simulate this type of fire scenario as well as a description of the manner in which the CAFE code couples the computational fluid dynamics and the finite element analysis techniques are also presented

  2. Characterization of an SRF gun: a 3D full wave simulation

    International Nuclear Information System (INIS)

    Wang, E.; Ben-Zvi, I.; Wang, J.

    2011-01-01

    We characterized a BNL 1.3GHz half-cell SRF gun is tested for GaAs photocathode. The gun already was simulated several years ago via two-dimensional (2D) numerical codes (i.e., Superfish and Parmela) with and without the beam. In this paper, we discuss our investigation of its characteristics using a three dimensional (3D) full-wave code (CST STUDIO SUITE(trademark)).The input/pickup couplers are sited symmetrically on the same side of the gun at an angle of 180 o . In particular, the inner conductor of the pickup coupler is considerably shorter than that of the input coupler. We evaluated the cross-talk between the beam (trajectory) and the signal on the input coupler compared our findings with published results based on analytical models. The CST STUDIO SUITE(trademark) also was used to predict the field within the cavity; particularly, a combination of transient/eigenmode solvers was employed to accurately construct the RF field for the particles, which also includes the effects of the couplers. Finally, we explored the beam's dynamics with a particle in cell (PIC) simulation, validated the results and compare them with 2D code result.

  3. Compressing an Ensemble with Statistical Models: An Algorithm for Global 3D Spatio-Temporal Temperature

    KAUST Repository

    Castruccio, Stefano

    2015-04-02

    One of the main challenges when working with modern climate model ensembles is the increasingly larger size of the data produced, and the consequent difficulty in storing large amounts of spatio-temporally resolved information. Many compression algorithms can be used to mitigate this problem, but since they are designed to compress generic scientific data sets, they do not account for the nature of climate model output and they compress only individual simulations. In this work, we propose a different, statistics-based approach that explicitly accounts for the space-time dependence of the data for annual global three-dimensional temperature fields in an initial condition ensemble. The set of estimated parameters is small (compared to the data size) and can be regarded as a summary of the essential structure of the ensemble output; therefore, it can be used to instantaneously reproduce the temperature fields in an ensemble with a substantial saving in storage and time. The statistical model exploits the gridded geometry of the data and parallelization across processors. It is therefore computationally convenient and allows to fit a non-trivial model to a data set of one billion data points with a covariance matrix comprising of 10^18 entries.

  4. Compressing an Ensemble with Statistical Models: An Algorithm for Global 3D Spatio-Temporal Temperature

    KAUST Repository

    Castruccio, Stefano; Genton, Marc G.

    2015-01-01

    One of the main challenges when working with modern climate model ensembles is the increasingly larger size of the data produced, and the consequent difficulty in storing large amounts of spatio-temporally resolved information. Many compression algorithms can be used to mitigate this problem, but since they are designed to compress generic scientific data sets, they do not account for the nature of climate model output and they compress only individual simulations. In this work, we propose a different, statistics-based approach that explicitly accounts for the space-time dependence of the data for annual global three-dimensional temperature fields in an initial condition ensemble. The set of estimated parameters is small (compared to the data size) and can be regarded as a summary of the essential structure of the ensemble output; therefore, it can be used to instantaneously reproduce the temperature fields in an ensemble with a substantial saving in storage and time. The statistical model exploits the gridded geometry of the data and parallelization across processors. It is therefore computationally convenient and allows to fit a non-trivial model to a data set of one billion data points with a covariance matrix comprising of 10^18 entries.

  5. PhysiCell: An open source physics-based cell simulator for 3-D multicellular systems

    Science.gov (United States)

    Ghaffarizadeh, Ahmadreza; Mumenthaler, Shannon M.

    2018-01-01

    Many multicellular systems problems can only be understood by studying how cells move, grow, divide, interact, and die. Tissue-scale dynamics emerge from systems of many interacting cells as they respond to and influence their microenvironment. The ideal “virtual laboratory” for such multicellular systems simulates both the biochemical microenvironment (the “stage”) and many mechanically and biochemically interacting cells (the “players” upon the stage). PhysiCell—physics-based multicellular simulator—is an open source agent-based simulator that provides both the stage and the players for studying many interacting cells in dynamic tissue microenvironments. It builds upon a multi-substrate biotransport solver to link cell phenotype to multiple diffusing substrates and signaling factors. It includes biologically-driven sub-models for cell cycling, apoptosis, necrosis, solid and fluid volume changes, mechanics, and motility “out of the box.” The C++ code has minimal dependencies, making it simple to maintain and deploy across platforms. PhysiCell has been parallelized with OpenMP, and its performance scales linearly with the number of cells. Simulations up to 105-106 cells are feasible on quad-core desktop workstations; larger simulations are attainable on single HPC compute nodes. We demonstrate PhysiCell by simulating the impact of necrotic core biomechanics, 3-D geometry, and stochasticity on the dynamics of hanging drop tumor spheroids and ductal carcinoma in situ (DCIS) of the breast. We demonstrate stochastic motility, chemical and contact-based interaction of multiple cell types, and the extensibility of PhysiCell with examples in synthetic multicellular systems (a “cellular cargo delivery” system, with application to anti-cancer treatments), cancer heterogeneity, and cancer immunology. PhysiCell is a powerful multicellular systems simulator that will be continually improved with new capabilities and performance improvements. It also

  6. Global 3D radiation-hydrodynamics models of AGB stars. Effects of convection and radial pulsations on atmospheric structures

    Science.gov (United States)

    Freytag, B.; Liljegren, S.; Höfner, S.

    2017-04-01

    Context. Observations of asymptotic giant branch (AGB) stars with increasing spatial resolution reveal new layers of complexity of atmospheric processes on a variety of scales. Aims: To analyze the physical mechanisms that cause asymmetries and surface structures in observed images, we use detailed 3D dynamical simulations of AGB stars; these simulations self-consistently describe convection and pulsations. Methods: We used the CO5BOLD radiation-hydrodynamics code to produce an exploratory grid of global "star-in-a-box" models of the outer convective envelope and the inner atmosphere of AGB stars to study convection, pulsations, and shock waves and their dependence on stellar and numerical parameters. Results: The model dynamics are governed by the interaction of long-lasting giant convection cells, short-lived surface granules, and strong, radial, fundamental-mode pulsations. Radial pulsations and shorter wavelength, traveling, acoustic waves induce shocks on various scales in the atmosphere. Convection, waves, and shocks all contribute to the dynamical pressure and, thus, to an increase of the stellar radius and to a levitation of material into layers where dust can form. Consequently, the resulting relation of pulsation period and stellar radius is shifted toward larger radii compared to that of non-linear 1D models. The dependence of pulsation period on luminosity agrees well with observed relations. The interaction of the pulsation mode with the non-stationary convective flow causes occasional amplitude changes and phase shifts. The regularity of the pulsations decreases with decreasing gravity as the relative size of convection cells increases. The model stars do not have a well-defined surface. Instead, the light is emitted from a very extended inhomogeneous atmosphere with a complex dynamic pattern of high-contrast features. Conclusions: Our models self-consistently describe convection, convectively generated acoustic noise, fundamental-mode radial

  7. Global solutions to random 3D vorticity equations for small initial data

    Science.gov (United States)

    Barbu, Viorel; Röckner, Michael

    2017-11-01

    One proves the existence and uniqueness in (Lp (R3)) 3, 3/2 4p - 6)3 with respect to the time variable. Furthermore, we obtain the pathwise continuous dependence of solutions with respect to the initial data. In particular, one gets a locally unique solution of 3D stochastic Navier-Stokes equation in vorticity form up to some explosion stopping time τ adapted to the Brownian motion.

  8. From micro-scale 3D simulations to macro-scale model of periodic porous media

    Science.gov (United States)

    Crevacore, Eleonora; Tosco, Tiziana; Marchisio, Daniele; Sethi, Rajandrea; Messina, Francesca

    2015-04-01

    In environmental engineering, the transport of colloidal suspensions in porous media is studied to understand the fate of potentially harmful nano-particles and to design new remediation technologies. In this perspective, averaging techniques applied to micro-scale numerical simulations are a powerful tool to extrapolate accurate macro-scale models. Choosing two simplified packing configurations of soil grains and starting from a single elementary cell (module), it is possible to take advantage of the periodicity of the structures to reduce the computation costs of full 3D simulations. Steady-state flow simulations for incompressible fluid in laminar regime are implemented. Transport simulations are based on the pore-scale advection-diffusion equation, that can be enriched introducing also the Stokes velocity (to consider the gravity effect) and the interception mechanism. Simulations are carried on a domain composed of several elementary modules, that serve as control volumes in a finite volume method for the macro-scale method. The periodicity of the medium involves the periodicity of the flow field and this will be of great importance during the up-scaling procedure, allowing relevant simplifications. Micro-scale numerical data are treated in order to compute the mean concentration (volume and area averages) and fluxes on each module. The simulation results are used to compare the micro-scale averaged equation to the integral form of the macroscopic one, making a distinction between those terms that could be computed exactly and those for which a closure in needed. Of particular interest it is the investigation of the origin of macro-scale terms such as the dispersion and tortuosity, trying to describe them with micro-scale known quantities. Traditionally, to study the colloidal transport many simplifications are introduced, such those concerning ultra-simplified geometry that usually account for a single collector. Gradual removal of such hypothesis leads to a

  9. Understanding the core-halo relation of quantum wave dark matter from 3D simulations.

    Science.gov (United States)

    Schive, Hsi-Yu; Liao, Ming-Hsuan; Woo, Tak-Pong; Wong, Shing-Kwong; Chiueh, Tzihong; Broadhurst, Tom; Hwang, W-Y Pauchy

    2014-12-31

    We examine the nonlinear structure of gravitationally collapsed objects that form in our simulations of wavelike cold dark matter, described by the Schrödinger-Poisson (SP) equation with a particle mass ∼10(-22)  eV. A distinct gravitationally self-bound solitonic core is found at the center of every halo, with a profile quite different from cores modeled in the warm or self-interacting dark matter scenarios. Furthermore, we show that each solitonic core is surrounded by an extended halo composed of large fluctuating dark matter granules which modulate the halo density on a scale comparable to the diameter of the solitonic core. The scaling symmetry of the SP equation and the uncertainty principle tightly relate the core mass to the halo specific energy, which, in the context of cosmological structure formation, leads to a simple scaling between core mass (Mc) and halo mass (Mh), Mc∝a(-1/2)Mh(1/3), where a is the cosmic scale factor. We verify this scaling relation by (i) examining the internal structure of a statistical sample of virialized halos that form in our 3D cosmological simulations and by (ii) merging multiple solitons to create individual virialized objects. Sufficient simulation resolution is achieved by adaptive mesh refinement and graphic processing units acceleration. From this scaling relation, present dwarf satellite galaxies are predicted to have kiloparsec-sized cores and a minimum mass of ∼10(8)M⊙, capable of solving the small-scale controversies in the cold dark matter model. Moreover, galaxies of 2×10(12)M⊙ at z=8 should have massive solitonic cores of ∼2×10(9)M⊙ within ∼60  pc. Such cores can provide a favorable local environment for funneling the gas that leads to the prompt formation of early stellar spheroids and quasars.

  10. A 3D gyrokinetic particle-in-cell simulation of fusion plasma microturbulence on parallel computers

    Science.gov (United States)

    Williams, T. J.

    1992-12-01

    One of the grand challenge problems now supported by HPCC is the Numerical Tokamak Project. A goal of this project is the study of low-frequency micro-instabilities in tokamak plasmas, which are believed to cause energy loss via turbulent thermal transport across the magnetic field lines. An important tool in this study is gyrokinetic particle-in-cell (PIC) simulation. Gyrokinetic, as opposed to fully-kinetic, methods are particularly well suited to the task because they are optimized to study the frequency and wavelength domain of the microinstabilities. Furthermore, many researchers now employ low-noise delta(f) methods to greatly reduce statistical noise by modelling only the perturbation of the gyrokinetic distribution function from a fixed background, not the entire distribution function. In spite of the increased efficiency of these improved algorithms over conventional PIC algorithms, gyrokinetic PIC simulations of tokamak micro-turbulence are still highly demanding of computer power--even fully-vectorized codes on vector supercomputers. For this reason, we have worked for several years to redevelop these codes on massively parallel computers. We have developed 3D gyrokinetic PIC simulation codes for SIMD and MIMD parallel processors, using control-parallel, data-parallel, and domain-decomposition message-passing (DDMP) programming paradigms. This poster summarizes our earlier work on codes for the Connection Machine and BBN TC2000 and our development of a generic DDMP code for distributed-memory parallel machines. We discuss the memory-access issues which are of key importance in writing parallel PIC codes, with special emphasis on issues peculiar to gyrokinetic PIC. We outline the domain decompositions in our new DDMP code and discuss the interplay of different domain decompositions suited for the particle-pushing and field-solution components of the PIC algorithm.

  11. Rn3D: A finite element code for simulating gas flow and radon transport in variably saturated, nonisothermal porous media

    International Nuclear Information System (INIS)

    Holford, D.J.

    1994-01-01

    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

  12. Validation of a 3D/1D Simulation Tool for ICRF Antennas

    International Nuclear Information System (INIS)

    Maggiora, R.; Lancellotti, V.; Milanesio, D.; Vecchi, G.; Kyrytsya, V.; Parisot, A.; Wukitch, S. J.

    2005-01-01

    TOPICA is an innovative tool for the simulation of the Ion Cyclotron Radio Frequency (ICRF) antenna systems that incorporates commercial-grade graphic interfaces into a fully 3D self-consistent description of the antenna geometry and an accurate description of the plasma; it can be considered as a 'Virtual Prototyping Laboratory' to assist the detailed design phase of the antenna system. Recent theoretical and computational advances of the TOPICA code has allowed to incorporate a CAD drawing capability of the antenna geometry, with fully 3D geometrical modeling, and to combine it with a 1D accurate plasma description that takes into account density and temperature profiles, and FLR effects; the profiles are inserted directly from measured data (when available), or specified analytically by the user. The coaxial feeding line is modeled as such; computation and visualization of relevant parameters (input scattering parameters, current and field distributions, etc.) complete the suite. The approach to the problem is based on an integral-equation formulation for the self-consistent evaluation of the current distribution on the conductors. The environment has been subdivided in two coupled region: the plasma region and the vacuum region. The two problems are linked self-consistently by representing the field continuity in terms of equivalent (unknown) sources. In the vacuum region all the calculations are executed in the spatial (configuration) domain, and this allows triangular-facet description of the arbitrarily shaped conductors and associated currents; in the plasma region a spectral representation of the fields is used, which allows to enter the plasma effect via a surface impedance matrix; for this reason any plasma model can be used, and at present the FELICE code has been adopted; special techniques have been adopted to increase the numerical efficiency. The TOPICA suite has been previously tested against assessed codes and against measurements of mock-ups and

  13. A nonlinear 3D real-time model for simulation of BWR nuclear power plants

    International Nuclear Information System (INIS)

    Ercan, Y.

    1982-02-01

    A nonlinear transient model for BWR nuclear power plants which consists of a 3D-core (subdivided into a number of superboxes, and with parallel flow and subcooled boiling), a top plenum, steam removal and feed water systems and main coolant recirculation pumps is given. The model describes the local core and global plant transient situation as dependent on both the inherent core dynamics and external control actions, i.e., disturbances such as motions of control rod banks, changes of mass flow rates of coolant, feed water and steam outlet. The case of a pressure-controlled reactor operation is also considered. The model which forms the basis for the digital code GARLIC-B (Er et al. 82) is aimed to be used on an on-site process computer in parallel to the actual reactor process (or even in predictive mode). Thus, special measures had to be taken into account in order to increase the computational speed and reduce the necessary computer storage. This could be achieved by - separating the neutron and power kinetics from the xenon-iodine dynamics, - treating the neutron kinetics and most of the thermodynamics and hydrodynamics in a pseudostationary way, - developing a special coupling coefficient concept to describe the neutron diffusion, calculating the coupling coefficients from a basic neutron kinetics code, - combining coarse mesh elements into superboxes, taking advantage of the symmetry properties of the core and - applying a sparse matrix technique for solving the resulting algebraic power equation system. (orig.) [de

  14. Software Development: 3D Animations and Creating User Interfaces for Realistic Simulations

    Science.gov (United States)

    Gordillo, Orlando Enrique

    2015-01-01

    My fall 2015 semester was spent at the Lyndon B. Johnson Space Center working in the Integrated Graphics, Operations, and Analysis Laboratory (IGOAL). My first project was to create a video animation that could tell the story of OMICS. OMICS is a term being used in the field of biomedical science to describe the collective technologies that study biological systems, such as what makes up a cell and how it functions with other systems. In the IGOAL I used a large 23 inch Wacom monitor to draw storyboards, graphics, and line art animations. I used Blender as the 3D environment to sculpt, shape, cut or modify the several scenes and models for the video. A challenge creating this video was to take a term used in biomedical science and describe it in such a way that an 8th grade student can understand. I used a line art style because it would visually set the tone for what we thought was an educational style. In order to get a handle on the perspective and overall feel for the animation without overloading my workspace, I split up the 2 minute animation into several scenes. I used Blender's python scripting capabilities which allowed for the addition of plugins to add or modify tools. The scripts can also directly interact with the objects to create naturalistic patterns or movements. After collecting the rendered scenes, I used Blender's built-in video editing workspace to output the animation. My second project was to write software that emulates a physical system's interface. The interface was to simulate a boat, ROV, and winch system. Simulations are a time and cost effective way to test complicated data and provide training for operators without having to use expensive hardware. We created the virtual controls with 3-D Blender models and 2-D graphics, and then add functionality in C# using the Unity game engine. The Unity engine provides several essential behaviors of a simulator, such as the start and update functions. A framework for Unity, which was developed in

  15. Simulation-Based Evaluation of Light Posts and Street Signs as 3-D Geolocation Targets in SAR Images

    Science.gov (United States)

    Auer, S.; Balss, U.

    2017-05-01

    The assignment of phase center positions (in 2D or 3D) derived from SAR data to physical object is challenging for many man-made structures such as buildings or bridges. In contrast, light poles and traffic signs are promising targets for tasks based on 3-D geolocation as they often show a prominent and spatially isolated appearance. For a detailed understanding of the nature of both targets, this paper presents results of a dedicated simulation case study, which is based on ray tracing methods (simulator RaySAR). For the first time, the appearance of the targets is analyzed in 2D (image plane) and 3D space (world coordinates of scene model) and reflecting surfaces are identified for related dominant image pixels. The case studies confirms the crucial impact of spatial resolution in the context of light poles and traffic signs and the appropriateness of light poles as target for 3-D geolocation in case of horizontal ground surfaces beneath.

  16. Toward a better integration of roughness in rockfall simulations - a sensitivity study with the RockyFor3D model

    Science.gov (United States)

    Monnet, Jean-Matthieu; Bourrier, Franck; Milenkovic, Milutin

    2017-04-01

    complex hillside is simulated by combining three components: a) a global trend (planar surface), b) local systematic components (sine waves), c) random roughness (Gaussian, zero-mean noise). The parameters for simulating these components are estimated for three typical scenarios of rockfall terrains: soft soil, fine scree and coarse scree, based on expert knowledge and available airborne and terrestrial laser scanning data. For each scenario, the reference terrain is created and used to compute input data for RockyFor3D simulations at different scales, i.e. DTMs with resolutions from 0.5 m to 20 m and associated roughness parameters. Subsequent analysis mainly focuses on the sensitivity of simulations both in terms of run-out envelope and kinetic energy distribution. Guidelines drawn from the results are expected to help experts handle the scale issue while integrating remote sensing data and field measurements of roughness in rockfall simulations.

  17. Development of 3D CFD simulation method in nuclear reactor safety analysis

    International Nuclear Information System (INIS)

    Rosli Darmawan; Mariah Adam

    2012-01-01

    One of the most prevailing issues in the operation of nuclear reactor is the safety of the system. Worldwide publicity on a few nuclear accidents as well as the notorious Hiroshima and Nagasaki bombing have always brought about public fear on anything related to nuclear. Most findings on the nuclear reactor accidents are closely related to the reactor cooling system. Thus, the understanding of the behaviour of reactor cooling system is very important to ensure the development and improvement on safety can be continuously done. Throughout the development of nuclear reactor technology, investigation and analysis on reactor safety have gone through several phases. In the early days, analytical and experimental methods were employed. For the last three decades 1D system level codes were widely used. The continuous development of nuclear reactor technology has brought about more complex system and processes of nuclear reactor operation. More detailed dimensional simulation codes are needed to assess these new reactors. This paper discusses the development of 3D CFD usage in nuclear reactor safety analysis worldwide. A brief review on the usage of CFD at Malaysia's Reactor TRIGA PUSPATI is also presented. (author)

  18. 3D Finite Element Simulation of Pellet-Cladding Mechanical Interaction

    International Nuclear Information System (INIS)

    Seo, Sang Kyu; Lee, Sung Uk; Lee, Eun Ho; Yang, Dong Yol; Kim, Hyo Chan; Yang, Dong Yol

    2016-01-01

    In a nuclear power plant, the fuel assembly, which is composed of fuel rods, burns, and the high temperature can generate power. The fuel rod consists of pellets and a cladding that covers the pellets. It is important to understand the pellet-cladding mechanical interaction with regard to nuclear safety. This paper proposes simulation of the PCMI. The gap between the pellets and the cladding, and the contact pressure are very important for conducting thermal analysis. Since the gap conductance is not known, it has to be determined by a suitable method. This paper suggests a solution. In this study, finite element (FE) contact analysis is conducted considering thermal expansion of the pellets. As the contact causes plastic deformation, this aspect is considered in the analysis. A 3D FE module is developed to analyze the PCMI using FORTRAN 90. The plastic deformation due to the contact between the pellets and the cladding is the major physical phenomenon. The simple analytical solution of a cylinder is proposed and compared with the fuel rod performance code results

  19. Evaluation of 3D modality-independent elastography for breast imaging: a simulation study

    International Nuclear Information System (INIS)

    Ou, J J; Ong, R E; Yankeelov, T E; Miga, M I

    2008-01-01

    This paper reports on the development and preliminary testing of a three-dimensional implementation of an inverse problem technique for extracting soft-tissue elasticity information via non-rigid model-based image registration. The modality-independent elastography (MIE) algorithm adjusts the elastic properties of a biomechanical model to achieve maximal similarity between images acquired under different states of static loading. A series of simulation experiments with clinical image sets of human breasts were performed to test the ability of the method to identify and characterize a radiographically occult stiff lesion. Because boundary conditions are a critical input to the algorithm, a comparison of three methods for semi-automated surface point correspondence was conducted in the context of systematic and randomized noise processes. The results illustrate that 3D MIE was able to successfully reconstruct elasticity images using data obtained from both magnetic resonance and x-ray computed tomography systems. The lesion was localized correctly in all cases and its relative elasticity found to be reasonably close to the true values (3.5% with the use of spatial priors and 11.6% without). In addition, the inaccuracies of surface registration performed with thin-plate spline interpolation did not exceed empiric thresholds of unacceptable boundary condition error

  20. In vitro bioactivity of 3D Ti-mesh with bioceramic coatings in simulated body fluid

    Directory of Open Access Journals (Sweden)

    Wei Yi

    2014-09-01

    Full Text Available 3D Ti-mesh has been coated with bioceramics under different coating conditions, such as material compositions and micro-porosity, using a dip casting method. Hydroxyapatite (HA, micro-HA particles (HAp, a bioglass (BG and their different mixtures together with polymer additives were used to control HA-coating microstructures. Layered composites with the following coating-to-substrate designs, such as BG/Ti, HA + BG/BG/Ti and HAp + BG/BG/Ti, were fabricated. The bioactivity of these coated composites and the uncoated Ti-mesh substrate was then investigated in a simulated body fluid (SBF. The Ti-mesh substrate and BG/Ti composite did not induce biomimetic apatite deposition when they were immersed in SBF for the selected BG, a pressable dental ceramic, used in this study. After seven days in SBF, an apatite layer was formed on both HA + BG/BG/Ti and HAp + BG/BG/Ti composites. The difference is the apatite layer on the HAp + BG/BG/Ti composite was rougher and contained more micro-pores, while the apatite layer on the HA + BG/BG/Ti composite was dense and smooth. The formation of biomimetic apatite, being more bioresorbable, is favored for bone regeneration.

  1. 3D Simulations of the ``Keyhole'' Hohlraum for Shock Timing on NIF

    Science.gov (United States)

    Robey, H. F.; Marinak, M. M.; Munro, D. H.; Jones, O. S.

    2007-11-01

    Ignition implosions planned for the National Ignition Facility (NIF) require a pulse shape with a carefully designed series of steps, which launch a series of shocks through the ablator and DT fuel. The relative timing of these shocks must be tuned to better than +/- 100ps to maintain the DT fuel on a sufficiently low adiabat. To meet these requirements, pre-ignition tuning experiments using a modified hohlraum geometry are being planned. This modified geometry, known as the ``keyhole'' hohlraum, adds a re-entrant gold cone, which passes through the hohlraum and capsule walls, to provide an optical line-of-sight to directly measure the shocks as they break out of the ablator. In order to assess the surrogacy of this modified geometry, 3D simulations using HYDRA [1] have been performed. The drive conditions and the resulting effect on shock timing in the keyhole hohlraum will be compared with the corresponding results for the standard ignition hohlraum. [1] M.M. Marinak, et al., Phys. Plasmas 8, 2275 (2001).

  2. Simulation of a 3D unsteady flow in an axial turbine stage

    Directory of Open Access Journals (Sweden)

    Straka Petr

    2012-04-01

    Full Text Available The contribution deals with a numerical simulation of an unsteady flow in an axial turbine stage. The solution is performed using an in-house numerical code developed in the Aeronautical and Test Institute, Plc. in Prague. The numerical code is based on a finite volume discretization of governing equations (Favre averaged Navier-Stokes equations and a two-equations turbulence model. The temporal integration is based on the implicit second-order backward Euler formula, which is realized through the iteration process in dual time. The proposed numerical method is used for solution of the 3D, unsteady, viscous turbulent flow of a perfect gas in the axial turbine stage. The flow path consists of an input nozzle, stator blade-wheel, rotor blade-wheel, a shroud-seal gap and a diffuser. Attention is paid to the influence of a secondary flow structures, such as generated vortices and flow in shroud-seal gap.

  3. Reconstruction of 3D Micro Pore Structure of Coal and Simulation of Its Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Guang-zhe Deng

    2017-01-01

    Full Text Available This article takes the low permeability coal seam in the coalfield of South Judger Basin in Xinjiang, as a research object. The pore structure characteristics of coal rock mass in low permeability coal seam were analyzed quantitatively using scanning electron microscopy (SEM through the methods of statistics and digital image analysis. Based on the pore structure parameters and the distribution function of the coal rock mass, a three-dimensional porous cylinder model with different porosity was reconstructed by FLAC3D. The numerical simulation study of reconstructed pore model shows that (1 the porosity and the compressive strength have obvious nonlinear relation and satisfy the negative exponential relation; (2 the porosity significantly affects the stress distribution; with the increase of micro porosity, the stress distribution becomes nonuniform; (3 the compressive failures of different models are mainly shear failures, and the shape of fracture section is related to porosity; (4 the variation of seepage coefficient of the pore reconstruction model is consistent with the development of micro cracks. The micro mechanism of the deformation and failure of coal and the interaction of multiphase flow with porosity are revealed, which provides a theoretical reference for the clean development of the low permeability coal seam.

  4. [Size dependent SERS activity of gold nanoparticles studied by 3D-FDTD simulation].

    Science.gov (United States)

    Li, Li-mei; Fang, Ping-ping; Yang, Zhi-lin; Huang, Wen-da; Wu, De-yin; Ren, Bin; Tian, Zhong-qun

    2009-05-01

    By synthesizing Au nanoparticles with the controllable size from about 16 to 160 nm and measuring their SERS activity, the authors found that Au nanoparticles film with a size in the range of 120-135 nm showed the highest SERS activity with the 632.8 nm excitation, which is different from previous experimental results and theoretical predictions. The three dimensional finite difference time domain (3D-FDTD)method was employed to simulate the size dependent SERS activity. At the 632.8 nm excitation, the particles with a size of 110 nm shows the highest enhancement under coupling condition and presents an enhancement as high as 10(9) at the hot site. If the enhancement is averaged over the whole surface, the enhancement can still be as high as 10(7), in good agreement with our experimental data. For Au nanoparticles with a larger size such as 220 nm, the multipolar effect leads to the appearance of the second maximum enhancement with the increase in particles size. The averaged enhancement for the excitation line of 325 nm is only 10(2).

  5. GMC Collisions as Triggers of Star Formation. II. 3D Turbulent, Magnetized Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Benjamin; Tan, Jonathan C. [Department of Physics, University of Florida, Gainesville, FL 32611 (United States); Nakamura, Fumitaka [National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Loo, Sven Van [School of Physics and Astronomy, University of Leeds (United Kingdom); Christie, Duncan [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Collins, David [Department of Physics, Florida State University, Tallahassee, FL 32306-4350 (United States)

    2017-02-01

    We investigate giant molecular cloud collisions and their ability to induce gravitational instability and thus star formation. This mechanism may be a major driver of star formation activity in galactic disks. We carry out a series of 3D, magnetohydrodynamics (MHD), adaptive mesh refinement simulations to study how cloud collisions trigger formation of dense filaments and clumps. Heating and cooling functions are implemented based on photo-dissociation region models that span the atomic-to-molecular transition and can return detailed diagnostic information. The clouds are initialized with supersonic turbulence and a range of magnetic field strengths and orientations. Collisions at various velocities and impact parameters are investigated. Comparing and contrasting colliding and non-colliding cases, we characterize morphologies of dense gas, magnetic field structure, cloud kinematic signatures, and cloud dynamics. We present key observational diagnostics of cloud collisions, especially: relative orientations between magnetic fields and density structures, like filaments; {sup 13}CO( J = 2-1), {sup 13}CO( J = 3-2), and {sup 12}CO( J = 8-7) integrated intensity maps and spectra; and cloud virial parameters. We compare these results to observed Galactic clouds.

  6. 3D thermal simulations and modeling of multi-finger InP DHBTs for millimeter-wave power amplifiers

    DEFF Research Database (Denmark)

    Midili, Virginio; Nodjiadjim, V.; Johansen, Tom Keinicke

    2017-01-01

    This paper presents the comparison between the simulated and measured thermal resistance of InP Double Heterojunction Bipolar Transistors (DHBT). 3D thermal simulations were carried out in order to compute the temperature distribution across the full structure due to a constant power excitation...

  7. Numerical Simulation of the Effect of 3D Needle Movement on Cavitation and Spray Formation in a Diesel Injector

    Science.gov (United States)

    Mandumpala Devassy, B.; Edelbauer, W.; Greif, D.

    2015-12-01

    Cavitation and its effect on spray formation and its dispersion play a crucial role in proper engine combustion and controlled emission. This study focuses on these effects in a typical common rail 6-hole diesel injector accounting for 3D needle movement and flow compressibility effects. Coupled numerical simulations using 1D and 3D CFD codes are used for this investigation. Previous studies in this direction have already presented a detailed structure of the adopted methodology. Compared to the previous analysis, the present study investigates the effect of 3D needle movement and cavitation on the spray formation for pilot and main injection events for a typical diesel engine operating point. The present setup performs a 3D compressible multiphase simulation coupled with a standalone 1D high pressure flow simulation. The simulation proceeds by the mutual communication between 1D and 3D solvers. In this work a typical common rail injector with a mini-sac nozzle is studied. The lateral and radial movement of the needle and its effect on the cavitation generation and the subsequent spray penetration are analyzed. The result indicates the effect of compressibility of the liquid on damping the needle forces, and also the difference in the spray penetration levels due to the asymmetrical flow field. Therefore, this work intends to provide an efficient and user-friendly engineering tool for simulating a complete fuel injector including spray propagation.

  8. Numerical Simulation of the Effect of 3D Needle Movement on Cavitation and Spray Formation in a Diesel Injector

    International Nuclear Information System (INIS)

    Devassy, B Mandumpala; Edelbauer, W; Greif, D

    2015-01-01

    Cavitation and its effect on spray formation and its dispersion play a crucial role in proper engine combustion and controlled emission. This study focuses on these effects in a typical common rail 6-hole diesel injector accounting for 3D needle movement and flow compressibility effects. Coupled numerical simulations using 1D and 3D CFD codes are used for this investigation. Previous studies in this direction have already presented a detailed structure of the adopted methodology. Compared to the previous analysis, the present study investigates the effect of 3D needle movement and cavitation on the spray formation for pilot and main injection events for a typical diesel engine operating point. The present setup performs a 3D compressible multiphase simulation coupled with a standalone 1D high pressure flow simulation. The simulation proceeds by the mutual communication between 1D and 3D solvers. In this work a typical common rail injector with a mini-sac nozzle is studied. The lateral and radial movement of the needle and its effect on the cavitation generation and the subsequent spray penetration are analyzed. The result indicates the effect of compressibility of the liquid on damping the needle forces, and also the difference in the spray penetration levels due to the asymmetrical flow field. Therefore, this work intends to provide an efficient and user-friendly engineering tool for simulating a complete fuel injector including spray propagation. (paper)

  9. A trend analysis methodology for enhanced validation of 3-D LWR core simulations

    International Nuclear Information System (INIS)

    Wieselquist, William; Ferroukhi, Hakim; Bernatowicz, Kinga

    2011-01-01

    This paper presents an approach that is being developed and implemented at PSI to enhance the Verification and Validation (V and V) procedure of 3-D static core simulations for the Swiss LWR reactors. The principle is to study in greater details the deviations between calculations and measurements and to assess on that basis if distinct trends of the accuracy can be observed. The presence of such trends could then be a useful indicator of eventual limitations/weaknesses in the applied lattice/core analysis methodology and could thereby serve as guidance for method/model enhancements. Such a trend analysis is illustrated here for a Swiss PWR core model using as basis, the state-of-the-art industrial CASMO/SIMULATE codes. The accuracy of the core-follow models to reproduce the periodic in-core neutron flux measurements is studied for a total of 21 operating cycles. The error is analyzed with respect to different physics parameters with a ranking of the individual assemblies/nodes contribution to the total RMS error and trends are analyzed by performing partial correlation analysis. The highest errors appear at the core axial peripheries (top/bottom nodes) where a mean C/E-1 error of 10% is observed for the top nodes and -5% for the bottom nodes and the maximum C/E-1 error reaches almost 20%. Partial correlation analysis shows significant correlation of error to distance from core mid-plane and only less significant correlations to other variables. Overall, it appears that the primary areas that could benefit from further method/modeling improvements are: axial reflectors, MOX treatment and control rod cusping. (author)

  10. Identification of slow magnetosonic wave trains and their evolution in 3-D compressible turbulence simulation

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2015-01-01

    Full Text Available In solar wind, dissipation of slow-mode magnetosonic waves may play a significant role in heating the solar wind, and these modes contribute essentially to the solar wind compressible turbulence. Most previous identifications of slow waves utilized the characteristic negative correlation between δ|B| and δρ. However, that criterion does not well identify quasi-parallel slow waves, for which δ|B| is negligible compared to δρ. Here we present a new method of identification, which will be used in 3-D compressible simulation. It is based on two criteria: (1 that VpB0 (phase speed projected along B0 is around ± cs, and that (2 there exists a clear correlation of δv|| and δρ. Our research demonstrates that if vA > cs, slow waves possess correlation between δv|| and δρ, with δρ / δv|| ≈ ± ρ0 / cs. This method helps us to distinguish slow-mode waves from fast and Alfvén waves, both of which do not have this polarity relation. The criteria are insensitive to the propagation angle θk B, defined as the angle between wave vector k and B0; they can be applied with a wide range of β if only vA > cs. In our numerical simulation, we have identified four cases of slow wave trains with this method. The slow wave trains seem to deform, probably caused by interaction with other waves; as a result, fast or Alfvén waves may be produced during the interaction and seem to propagate bidirectionally away. Our identification and analysis of the wave trains provide useful methods for investigations of compressible turbulence in the solar wind or in similar environments, and will thus deepen understandings of slow waves in the turbulence.

  11. Mapping of coma anisotropies to plasma structures of weak comets: a 3-D hybrid simulation study

    Directory of Open Access Journals (Sweden)

    N. Gortsas

    2009-04-01

    Full Text Available The effects of coma anisotropies on the plasma environment of comets have been studied by means of a 3-D hybrid model which treats electrons as a massless, charge-neutralizing fluid, whereas ion dynamics are covered by a kinetic approach. From Earth-based observations as well as from in-situ spacecraft measurements the shape of the coma of many comets is ascertained to be anisotropic. However, most plasma simulation studies deploy a spherically symmetric activity pattern. In this paper anisotropy is studied by considering three different coma shape models. The first model is derived from the Haser model and is characterised by spherically symmetry. This reference model is then compared with two different neutral gas shape models: the dayside restricted model with no nightside activity and a cone shaped model with opening angle of π/2. In all models the integrated surface activity is kept constant. The simulations have been done for the Rosetta target comet 67P/Churyumov-Gerasimenko for two heliocentric distances, 1.30 AU and 3.25 AU. It is found that shock formation processes are modified as a result of increasing spatial confinement. Characteristic plasma structures of comets such as the bow shock, magnetic barrier region and the ion composition boundary exhibit a shift towards the sun. In addition, the cone shaped model leads to a strong increase of the mass-loaded region which in turn leads to a smooth deceleration of the solar wind flow and an increasing degree of mixture between the solar wind and cometary ion species. This creates an additional transport channel of the magnetic field from the magnetic barrier region away which in turn leads to a broadening of this region. In addition, it leads to an ion composition boundary which is only gradually developed.

  12. Modeling and simulation of viscoelastic biological particles' 3D manipulation using atomic force microscopy

    Science.gov (United States)

    Korayem, M. H.; Habibi Sooha, Y.; Rastegar, Z.

    2018-05-01

    Manipulation of the biological particles by atomic force microscopy is used to transfer these particles inside body's cells, diagnosis and destruction of the cancer cells and drug delivery to damaged cells. According to the impossibility of simultaneous observation of this process, the importance of modeling and simulation can be realized. The contact of the tip with biological particle is important during manipulation, therefore, the first step of the modeling is choosing appropriate contact model. Most of the studies about contact between atomic force microscopy and biological particles, consider the biological particle as an elastic material. This is not an appropriate assumption because biological cells are basically soft and this assumption ignores loading history. In this paper, elastic and viscoelastic JKR theories were used in modeling and simulation of the 3D manipulation for three modes of tip-particle sliding, particle-substrate sliding and particle-substrate rolling. Results showed that critical force and time in motion modes (sliding and rolling) for two elastic and viscoelastic states are very close but these magnitudes were lower in the viscoelastic state. Then, three friction models, Coulomb, LuGre and HK, were used for tip-particle sliding mode in the first phase of manipulation to make results closer to reality. In both Coulomb and LuGre models, critical force and time are very close for elastic and viscoelastic states but in general critical force and time prediction of HK model was higher than LuGre and the LuGre model itself had higher prediction than Coulomb.

  13. 3D visualization of ultra-fine ICON climate simulation data

    Science.gov (United States)

    Röber, Niklas; Spickermann, Dela; Böttinger, Michael

    2016-04-01

    Advances in high performance computing and model development allow the simulation of finer and more detailed climate experiments. The new ICON model is based on an unstructured triangular grid and can be used for a wide range of applications, ranging from global coupled climate simulations down to very detailed and high resolution regional experiments. It consists of an atmospheric and an oceanic component and scales very well for high numbers of cores. This allows us to conduct very detailed climate experiments with ultra-fine resolutions. ICON is jointly developed in partnership with DKRZ by the Max Planck Institute for Meteorology and the German Weather Service. This presentation discusses our current workflow for analyzing and visualizing this high resolution data. The ICON model has been used for eddy resolving (developed specific plugins for the free available visualization software ParaView and Vapor, which allows us to read and handle that much data. Within ParaView, we can additionally compare prognostic variables with performance data side by side to investigate the performance and scalability of the model. With the simulation running in parallel on several hundred nodes, an equal load balance is imperative. In our presentation we show visualizations of high-resolution ICON oceanographic and HDCP2 atmospheric simulations that were created using ParaView and Vapor. Furthermore we discuss our current efforts to improve our visualization capabilities, thereby exploring the potential of regular in-situ visualization, as well as of in-situ compression / post visualization.

  14. Simulating Small-Scale Experiments of In-Tunnel Airblast Using STUN and ALE3D

    Energy Technology Data Exchange (ETDEWEB)

    Neuscamman, Stephanie [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glenn, Lewis [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schebler, Gregory [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McMichael, Larry [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glascoe, Lee [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2011-09-12

    This report details continuing validation efforts for the Sphere and Tunnel (STUN) and ALE3D codes. STUN has been validated previously for blast propagation through tunnels using several sets of experimental data with varying charge sizes and tunnel configurations, including the MARVEL nuclear driven shock tube experiment (Glenn, 2001). The DHS-funded STUNTool version is compared to experimental data and the LLNL ALE3D hydrocode. In this particular study, we compare the performance of the STUN and ALE3D codes in modeling an in-tunnel airblast to experimental results obtained by Lunderman and Ohrt in a series of small-scale high explosive experiments (1997).

  15. Parameterization experiments performed via synthetic mass movements prototypes generated by 3D slope stability simulator

    Science.gov (United States)

    Colangelo, Antonio C.

    2010-05-01

    each cell in synthetic slope systems performed by relief unity emulator. The central methodological strategy is to locate the potential rupture surfaces (prs), main material discontinuities, like soil-regolith or regolith-rock transitions. Inner these "prs", we would to outline the effective potential rupture surfaces (eprs). This surface is a sub-set of the "prs" that presents safety factor less than unity (fwalls, the "slope stability simulator" generates a synthetic mass movement. The overlay material will slide until that a new equilibrium be attained at residual shear strength. These devices generate graphic 3D cinematic sequences of experiments in synthetic slope systems and numerical results about physical and morphological data about scars and deposits. Thus, we have a detailed geotechnical, morphological, topographic and morphometric description of these mass movements prototypes, for deal with effective mass movements found in the real environments.

  16. Websim3d: A Web-based System for Generation, Storage and Dissemination of Earthquake Ground Motion Simulations.

    Science.gov (United States)

    Olsen, K. B.

    2003-12-01

    Synthetic time histories from large-scale 3D ground motion simulations generally constitute large 'data' sets which typically require 100's of Mbytes or Gbytes of storage capacity. For the same reason, getting access to a researchers simulation output, for example for an earthquake engineer to perform site analysis, or a seismologist to perform seismic hazard analysis, can be a tedious procedure. To circumvent this problem we have developed a web-based ``community model'' (websim3D) for the generation, storage, and dissemination of ground motion simulation results. Websim3D allows user-friendly and fast access to view and download such simulation results for an earthquake-prone area. The user selects an earthquake scenario from a map of the region, which brings up a map of the area where simulation data is available. Now, by clicking on an arbitrary site location, synthetic seismograms and/or soil parameters for the site can be displayed at fixed or variable scaling and/or downloaded. Websim3D relies on PHP scripts for the dynamic plots of synthetic seismograms and soil profiles. Although not limited to a specific area, we illustrate the community model for simulation results from the Los Angeles basin, Wellington (New Zealand), and Mexico.

  17. Savage Modeling and Analysis Language (SMAL): Metadata for Tactical Simulations and X3D Visualizations

    National Research Council Canada - National Science Library

    Rauch, Travis M

    2006-01-01

    Visualizing operations environments in three-dimensions is in keeping with the military's drive to increase the speed and accuracy with which warfighters make decisions in the command center and in the field. Three-dimensional (3D...

  18. Simulation study of a 3-D device integrating FinFET and UTBFET

    KAUST Repository

    Fahad, Hossain M.; Hu, Chenming; Hussain, Muhammad Mustafa

    2015-01-01

    By integrating 3-D nonplanar fins and 2-D ultrathin bodies, wavy FinFETs merge two formerly competing technologies on a silicon-on-insulator platform to deliver enhanced transistor performance compared with conventional trigate Fin

  19. Simulation software of 3-D two-neutron energy groups for ship reactor with hexagonal fuel subassembly

    International Nuclear Information System (INIS)

    Zhang Fan; Cai Zhangsheng; Yu Lei; Gui Xuewen

    2005-01-01

    Core simulation software for 3-D two-neutron energy groups is developed. This software is used to simulate the ship reactor with hexagonal fuel subassembly after 10, 150 and 200 burnup days, considering the hydraulic and thermal feedback. It accurately simulates the characteristics of the fast and thermal neutrons and the detailed power distribution in a reactor under normal and abnormal operation condition. (authors)

  20. A PFC3D-based numerical simulation of cutting load for lunar rock simulant and experimental validation

    Science.gov (United States)

    Li, Peng; Jiang, Shengyuan; Tang, Dewei; Xu, Bo

    2017-05-01

    For sake of striking a balance between the need of drilling efficiency and the constrains of power budget on the moon, the penetrations per revolution of drill bit are generally limited in the range around 0.1 mm, and besides the geometric angle of the cutting blade need to be well designed. This paper introduces a simulation approach based on PFC3D (particle flow code 3 dimensions) for analyzing the cutting load feature on lunar rock simulant, which is derived from different geometric-angle blades with a small cutting depth. The mean values of the cutting force of five blades in the survey region (four on the boundary points and one on the center point) are selected as the macroscopic responses of model. The method of experimental design which includes Plackett-Burman (PB) design and central composite design (CCD) method is adopted in the matching procedure of microparameters in PFC model. Using the optimization method of enumeration, the optimum set of microparameters is acquired. Then, the experimental validation is implemented by using other twenty-five blades with different geometric angles, and the results from both simulations and laboratory tests give fair agreements. Additionally, the rock breaking process cut by different blades are quantified from simulation analysis. This research provides the theoretical support for the refinement of the rock cutting load prediction and the geometric design of cutting blade on the drill bit.

  1. Numerical Benchmark of 3D Ground Motion Simulation in the Alpine valley of Grenoble, France.

    Science.gov (United States)

    Tsuno, S.; Chaljub, E.; Cornou, C.; Bard, P.

    2006-12-01

    Thank to the use of sophisticated numerical methods and to the access to increasing computational resources, our predictions of strong ground motion become more and more realistic and need to be carefully compared. We report our effort of benchmarking numerical methods of ground motion simulation in the case of the valley of Grenoble in the French Alps. The Grenoble valley is typical of a moderate seismicity area where strong site effects occur. The benchmark consisted in computing the seismic response of the `Y'-shaped Grenoble valley to (i) two local earthquakes (Mlhandle surface topography, the other half comprises predictions based upon 1D (2 contributions), 2D (4 contributions) and empirical Green's function (EGF) (3 contributions) methods. Maximal frequency analysed ranged between 2.5 Hz for 3D calculations and 40 Hz for EGF predictions. We present a detailed comparison of the different predictions using raw indicators (e.g. peak values of ground velocity and acceleration, Fourier spectra, site over reference spectral ratios, ...) as well as sophisticated misfit criteria based upon previous works [2,3]. We further discuss the variability in estimating the importance of particular effects such as non-linear rheology, or surface topography. References: [1] Thouvenot F. et al., The Belledonne Border Fault: identification of an active seismic strike-slip fault in the western Alps, Geophys. J. Int., 155 (1), p. 174-192, 2003. [2] Anderson J., Quantitative measure of the goodness-of-fit of synthetic seismograms, proceedings of the 13th World Conference on Earthquake Engineering, Vancouver, paper #243, 2004. [3] Kristekova M. et al., Misfit Criteria for Quantitative Comparison of Seismograms, Bull. Seism. Soc. Am., in press, 2006.

  2. Influence of Slope-Scale Snowmelt on Catchment Response Simulated With the Alpine3D Model

    Science.gov (United States)

    Brauchli, Tristan; Trujillo, Ernesto; Huwald, Hendrik; Lehning, Michael

    2017-12-01

    Snow and hydrological modeling in alpine environments remains challenging because of the complexity of the processes affecting the mass and energy balance. This study examines the influence of snowmelt on the hydrological response of a high-alpine catchment of 43.2 km2 in the Swiss Alps during the water year 2014-2015. Based on recent advances in Alpine3D, we examine how snow distributions and liquid water transport within the snowpack influence runoff dynamics. By combining these results with multiscale observations (snow lysimeter, distributed snow depths, and streamflow), we demonstrate the added value of a more realistic snow distribution at the onset of melt season. At the site scale, snowpack runoff is well simulated when the mass balance errors are corrected (R2 = 0.95 versus R2 = 0.61). At the subbasin scale, a more heterogeneous snowpack leads to a more rapid runoff pulse originating in the shallower areas while an extended melting period (by a month) is caused by snowmelt from deeper areas. This is a marked improvement over results obtained using a traditional precipitation interpolation method. Hydrological response is also improved by the more realistic snowpack (NSE of 0.85 versus 0.74), even though calibration processes smoothen out the differences. The added value of a more complex liquid water transport scheme is obvious at the site scale but decreases at larger scales. Our results highlight not only the importance but also the difficulty of getting a realistic snowpack distribution even in a well-instrumented area and present a model validation from multiscale experimental data sets.

  3. A numerical method for simulating the dynamics of 3D axisymmetric vesicles suspended in viscous flows

    Science.gov (United States)

    Veerapaneni, Shravan K.; Gueyffier, Denis; Biros, George; Zorin, Denis

    2009-10-01

    We extend [Shravan K. Veerapaneni, Denis Gueyffier, Denis Zorin, George Biros, A boundary integral method for simulating the dynamics of inextensible vesicles suspended in a viscous fluid in 2D, Journal of Computational Physics 228(7) (2009) 2334-2353] to the case of three-dimensional axisymmetric vesicles of spherical or toroidal topology immersed in viscous flows. Although the main components of the algorithm are similar in spirit to the 2D case—spectral approximation in space, semi-implicit time-stepping scheme—the main differences are that the bending and viscous force require new analysis, the linearization for the semi-implicit schemes must be rederived, a fully implicit scheme must be used for the toroidal topology to eliminate a CFL-type restriction and a novel numerical scheme for the evaluation of the 3D Stokes single layer potential on an axisymmetric surface is necessary to speed up the calculations. By introducing these novel components, we obtain a time-scheme that experimentally is unconditionally stable, has low cost per time step, and is third-order accurate in time. We present numerical results to analyze the cost and convergence rates of the scheme. To verify the solver, we compare it to a constrained variational approach to compute equilibrium shapes that does not involve interactions with a viscous fluid. To illustrate the applicability of method, we consider a few vesicle-flow interaction problems: the sedimentation of a vesicle, interactions of one and three vesicles with a background Poiseuille flow.

  4. Geometric and mechanical evaluation of 3D-printing materials for skull base anatomical education and endoscopic surgery simulation - A first step to create reliable customized simulators.

    Directory of Open Access Journals (Sweden)

    Valentin Favier

    Full Text Available Endoscopic skull base surgery allows minimal invasive therapy through the nostrils to treat infectious or tumorous diseases. Surgical and anatomical education in this field is limited by the lack of validated training models in terms of geometric and mechanical accuracy. We choose to evaluate several consumer-grade materials to create a patient-specific 3D-printed skull base model for anatomical learning and surgical training.Four 3D-printed consumer-grade materials were compared to human cadaver bone: calcium sulfate hemihydrate (named Multicolor, polyamide, resin and polycarbonate. We compared the geometric accuracy, forces required to break thin walls of materials and forces required during drilling.All materials had an acceptable global geometric accuracy (from 0.083mm to 0.203mm of global error. Local accuracy was better in polycarbonate (0.09mm and polyamide (0.15mm than in Multicolor (0.90mm and resin (0.86mm. Resin and polyamide thin walls were not broken at 200N. Forces needed to break Multicolor thin walls were 1.6-3.5 times higher than in bone. For polycarbonate, forces applied were 1.6-2.5 times higher. Polycarbonate had a mode of fracture similar to the cadaver bone. Forces applied on materials during drilling followed a normal distribution except for the polyamide which was melted. Energy spent during drilling was respectively 1.6 and 2.6 times higher on bone than on PC and Multicolor.Polycarbonate is a good substitute of human cadaver bone for skull base surgery simulation. Thanks to short lead times and reasonable production costs, patient-specific 3D printed models can be used in clinical practice for pre-operative training, improving patient safety.

  5. Geometric and mechanical evaluation of 3D-printing materials for skull base anatomical education and endoscopic surgery simulation - A first step to create reliable customized simulators.

    Science.gov (United States)

    Favier, Valentin; Zemiti, Nabil; Caravaca Mora, Oscar; Subsol, Gérard; Captier, Guillaume; Lebrun, Renaud; Crampette, Louis; Mondain, Michel; Gilles, Benjamin

    2017-01-01

    Endoscopic skull base surgery allows minimal invasive therapy through the nostrils to treat infectious or tumorous diseases. Surgical and anatomical education in this field is limited by the lack of validated training models in terms of geometric and mechanical accuracy. We choose to evaluate several consumer-grade materials to create a patient-specific 3D-printed skull base model for anatomical learning and surgical training. Four 3D-printed consumer-grade materials were compared to human cadaver bone: calcium sulfate hemihydrate (named Multicolor), polyamide, resin and polycarbonate. We compared the geometric accuracy, forces required to break thin walls of materials and forces required during drilling. All materials had an acceptable global geometric accuracy (from 0.083mm to 0.203mm of global error). Local accuracy was better in polycarbonate (0.09mm) and polyamide (0.15mm) than in Multicolor (0.90mm) and resin (0.86mm). Resin and polyamide thin walls were not broken at 200N. Forces needed to break Multicolor thin walls were 1.6-3.5 times higher than in bone. For polycarbonate, forces applied were 1.6-2.5 times higher. Polycarbonate had a mode of fracture similar to the cadaver bone. Forces applied on materials during drilling followed a normal distribution except for the polyamide which was melted. Energy spent during drilling was respectively 1.6 and 2.6 times higher on bone than on PC and Multicolor. Polycarbonate is a good substitute of human cadaver bone for skull base surgery simulation. Thanks to short lead times and reasonable production costs, patient-specific 3D printed models can be used in clinical practice for pre-operative training, improving patient safety.

  6. Large Time Behavior for Weak Solutions of the 3D Globally Modified Navier-Stokes Equations

    Directory of Open Access Journals (Sweden)

    Junbai Ren

    2014-01-01

    Full Text Available This paper is concerned with the large time behavior of the weak solutions for three-dimensional globally modified Navier-Stokes equations. With the aid of energy methods and auxiliary decay estimates together with Lp-Lq estimates of heat semigroup, we derive the optimal upper and lower decay estimates of the weak solutions for the globally modified Navier-Stokes equations as C1(1+t-3/4≤uL2≤C2(1+t-3/4,  t>1. The decay rate is optimal since it coincides with that of heat equation.

  7. 3-D simulations of M9 earthquakes on the Cascadia Megathrust: Key parameters and uncertainty

    Science.gov (United States)

    Wirth, Erin; Frankel, Arthur; Vidale, John; Marafi, Nasser A.; Stephenson, William J.

    2017-01-01

    Geologic and historical records indicate that the Cascadia subduction zone is capable of generating large, megathrust earthquakes up to magnitude 9. The last great Cascadia earthquake occurred in 1700, and thus there is no direct measure on the intensity of ground shaking or specific rupture parameters from seismic recordings. We use 3-D numerical simulations to generate broadband (0-10 Hz) synthetic seismograms for 50 M9 rupture scenarios on the Cascadia megathrust. Slip consists of multiple high-stress drop subevents (~M8) with short rise times on the deeper portion of the fault, superimposed on a background slip distribution with longer rise times. We find a >4x variation in the intensity of ground shaking depending upon several key parameters, including the down-dip limit of rupture, the slip distribution and location of strong-motion-generating subevents, and the hypocenter location. We find that extending the down-dip limit of rupture to the top of the non-volcanic tremor zone results in a ~2-3x increase in peak ground acceleration for the inland city of Seattle, Washington, compared to a completely offshore rupture. However, our simulations show that allowing the rupture to extend to the up-dip limit of tremor (i.e., the deepest rupture extent in the National Seismic Hazard Maps), even when tapering the slip to zero at the down-dip edge, results in multiple areas of coseismic coastal uplift. This is inconsistent with coastal geologic evidence (e.g., buried soils, submerged forests), which suggests predominantly coastal subsidence for the 1700 earthquake and previous events. Defining the down-dip limit of rupture as the 1 cm/yr locking contour (i.e., mostly offshore) results in primarily coseismic subsidence at coastal sites. We also find that the presence of deep subevents can produce along-strike variations in subsidence and ground shaking along the coast. Our results demonstrate the wide range of possible ground motions from an M9 megathrust earthquake in

  8. Can molecular dynamics simulations help in discriminating correct from erroneous protein 3D models?

    Directory of Open Access Journals (Sweden)

    Gibrat Jean-François

    2008-01-01

    Full Text Available Abstract Background Recent approaches for predicting the three-dimensional (3D structure of proteins such as de novo or fold recognition methods mostly rely on simplified energy potential functions and a reduced representation of the polypeptide chain. These simplifications facilitate the exploration of the protein conformational space but do not permit to capture entirely the subtle relationship that exists between the amino acid sequence and its native structure. It has been proposed that physics-based energy functions together with techniques for sampling the conformational space, e.g., Monte Carlo or molecular dynamics (MD simulations, are better suited to the task of modelling proteins at higher resolutions than those of models obtained with the former type of methods. In this study we monitor different protein structural properties along MD trajectories to discriminate correct from erroneous models. These models are based on the sequence-structure alignments provided by our fold recognition method, FROST. We define correct models as being built from alignments of sequences with structures similar to their native structures and erroneous models from alignments of sequences with structures unrelated to their native structures. Results For three test sequences whose native structures belong to the all-α, all-β and αβ classes we built a set of models intended to cover the whole spectrum: from a perfect model, i.e., the native structure, to a very poor model, i.e., a random alignment of the test sequence with a structure belonging to another structural class, including several intermediate models based on fold recognition alignments. We submitted these models to 11 ns of MD simulations at three different temperatures. We monitored along the corresponding trajectories the mean of the Root-Mean-Square deviations (RMSd with respect to the initial conformation, the RMSd fluctuations, the number of conformation clusters, the evolution of

  9. Investigating the generation of Love waves in secondary microseisms using 3D numerical simulations

    Science.gov (United States)

    Wenk, Stefan; Hadziioannou, Celine; Pelties, Christian; Igel, Heiner

    2014-05-01

    Longuet-Higgins (1950) proposed that secondary microseismic noise can be attributed to oceanic disturbances by surface gravity wave interference causing non-linear, second-order pressure perturbations at the ocean bottom. As a first approximation, this source mechanism can be considered as a force acting normal to the ocean bottom. In an isotropic, layered, elastic Earth model with plain interfaces, vertical forces generate P-SV motions in the vertical plane of source and receiver. In turn, only Rayleigh waves are excited at the free surface. However, several authors report on significant Love wave contributions in the secondary microseismic frequency band of real data measurements. The reason is still insufficiently analysed and several hypothesis are under debate: - The source mechanism has strongest influence on the excitation of shear motions, whereas the source direction dominates the effect of Love wave generation in case of point force sources. Darbyshire and Okeke (1969) proposed the topographic coupling effect of pressure loads acting on a sloping sea-floor to generate the shear tractions required for Love wave excitation. - Rayleigh waves can be converted into Love waves by scattering. Therefore, geometric scattering at topographic features or internal scattering by heterogeneous material distributions can cause Love wave generation. - Oceanic disturbances act on large regions of the ocean bottom, and extended sources have to be considered. In combination with topographic coupling and internal scattering, the extent of the source region and the timing of an extended source should effect Love wave excitation. We try to elaborate the contribution of different source mechanisms and scattering effects on Love to Rayleigh wave energy ratios by 3D numerical simulations. In particular, we estimate the amount of Love wave energy generated by point and extended sources acting on the free surface. Simulated point forces are modified in their incident angle, whereas

  10. Precipitation processes developed during TOGA COARE (1992), GATE (1974), SCSMEX (1998), and KWAJEX (1999): 3D Cloud Resolving Model Simulation

    Science.gov (United States)

    Tao, W.-K.

    2006-01-01

    Real clouds and cloud systems are inherently three-dimensional (3D). Because of the limitations in computer resources, however, most cloud-resolving models (CRMs) today are still two-dimensional (2D). A few 3D CRMs have been used to study the response of clouds to large-scale forcing. In these 3D simulations, the model domain was small, and the integration time was 6 hours. Only recently have 3D experiments been performed for multi-day periods for tropical cloud systems with large horizontal domains at the National Center for Atmospheric Research (NCAR), NOAA GFDL, the U.K. Met. Office, Colorado State University and NASA Goddard Space Flight Center. An improved 3D Goddard Cumulus Ensemble (GCE) model was recently used to simulate periods during TOGA COARE (December 19-27, 1992), GATE (september 1-7, 1974), SCSMEX (May 18-26, June 2-11, 1998) and KWAJEX (August 7-13, August 18-21, and August 29-September 12, 1999) using a 512 by 512 km domain and 41 vertical layers. The major objectives of this paper are: (1) to identify the differences and similarities in the simulated precipitation processes and their associated surface and water energy budgets in TOGA COARE, GATE, KWAJEX, and SCSMEX, and (2) to asses the impact of microphysics, radiation budget and surface fluxes on the organization of convection in tropics.

  11. SU-F-T-184: 3D Range-Modulator for Scanned Particle Therapy: Development, Monte Carlo Simulations and Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Simeonov, Y; Penchev, P; Ringbaek, T Printz [University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen (Germany); Brons, S [Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg (Germany); Weber, U [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Zink, K [University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen (Germany); University Hospital Giessen-Marburg, Marburg (Germany)

    2016-06-15

    Purpose: Active raster scanning in particle therapy results in highly conformal dose distributions. Treatment time, however, is relatively high due to the large number of different iso-energy layers used. By using only one energy and the so called 3D range-modulator irradiation times of a few seconds only can be achieved, thus making delivery of homogeneous dose to moving targets (e.g. lung cancer) more reliable. Methods: A 3D range-modulator consisting of many pins with base area of 2.25 mm2 and different lengths was developed and manufactured with rapid prototyping technique. The form of the 3D range-modulator was optimised for a spherical target volume with 5 cm diameter placed at 25 cm in a water phantom. Monte Carlo simulations using the FLUKA package were carried out to evaluate the modulating effect of the 3D range-modulator and simulate the resulting dose distribution. The fine and complicated contour form of the 3D range-modulator was taken into account by a specially programmed user routine. Additionally FLUKA was extended with the capability of intensity modulated scanning. To verify the simulation results dose measurements were carried out at the Heidelberg Ion Therapy Center (HIT) with a 400.41 MeV 12C beam. Results: The high resolution measurements show that the 3D range-modulator is capable of producing homogeneous 3D conformal dose distributions, simultaneously reducing significantly irradiation time. Measured dose is in very good agreement with the previously conducted FLUKA simulations, where slight differences were traced back to minor manufacturing deviations from the perfect optimised form. Conclusion: Combined with the advantages of very short treatment time the 3D range-modulator could be an alternative to treat small to medium sized tumours (e.g. lung metastasis) with the same conformity as full raster-scanning treatment. Further simulations and measurements of more complex cases will be conducted to investigate the full potential of the 3D

  12. In-cloud oxalate formation in the global troposphere: A 3-D modeling study

    NARCIS (Netherlands)

    Myriokefalitakis, S.; Tsigaridis, K.; Mihalopoulos, N.; Sciare, J.; Nenes, A.; Kawamura, K.; Segers, A.; Kanakidou, M.

    2011-01-01

    Organic acids attract increasing attention as contributors to atmospheric acidity, secondary organic aerosol mass and aerosol hygroscopicity. Oxalic acid is globally the most abundant dicarboxylic acid, formed via chemical oxidation of gas-phase precursors in the aqueous phase of aerosols and

  13. Solar Potential Analysis and Integration of the Time-Dependent Simulation Results for Semantic 3d City Models Using Dynamizers

    Science.gov (United States)

    Chaturvedi, K.; Willenborg, B.; Sindram, M.; Kolbe, T. H.

    2017-10-01

    Semantic 3D city models play an important role in solving complex real-world problems and are being adopted by many cities around the world. A wide range of application and simulation scenarios directly benefit from the adoption of international standards such as CityGML. However, most of the simulations involve properties, whose values vary with respect to time, and the current generation semantic 3D city models do not support time-dependent properties explicitly. In this paper, the details of solar potential simulations are provided operating on the CityGML standard, assessing and estimating solar energy production for the roofs and facades of the 3D building objects in different ways. Furthermore, the paper demonstrates how the time-dependent simulation results are better-represented inline within 3D city models utilizing the so-called Dynamizer concept. This concept not only allows representing the simulation results in standardized ways, but also delivers a method to enhance static city models by such dynamic property values making the city models truly dynamic. The dynamizer concept has been implemented as an Application Domain Extension of the CityGML standard within the OGC Future City Pilot Phase 1. The results are given in this paper.

  14. An Interactive 3D Virtual Anatomy Puzzle for Learning and Simulation - Initial Demonstration and Evaluation.

    Science.gov (United States)

    Messier, Erik; Wilcox, Jascha; Dawson-Elli, Alexander; Diaz, Gabriel; Linte, Cristian A

    2016-01-01

    To inspire young students (grades 6-12) to become medical practitioners and biomedical engineers, it is necessary to expose them to key concepts of the field in a way that is both exciting and informative. Recent advances in medical image acquisition, manipulation, processing, visualization, and display have revolutionized the approach in which the human body and internal anatomy can be seen and studied. It is now possible to collect 3D, 4D, and 5D medical images of patient specific data, and display that data to the end user using consumer level 3D stereoscopic display technology. Despite such advancements, traditional 2D modes of content presentation such as textbooks and slides are still the standard didactic equipment used to teach young students anatomy. More sophisticated methods of display can help to elucidate the complex 3D relationships between structures that are so often missed when viewing only 2D media, and can instill in students an appreciation for the interconnection between medicine and technology. Here we describe the design, implementation, and preliminary evaluation of a 3D virtual anatomy puzzle dedicated to helping users learn the anatomy of various organs and systems by manipulating 3D virtual data. The puzzle currently comprises several components of the human anatomy and can be easily extended to include additional organs and systems. The 3D virtual anatomy puzzle game was implemented and piloted using three display paradigms - a traditional 2D monitor, a 3D TV with active shutter glass, and the DK2 version Oculus Rift, as well as two different user interaction devices - a space mouse and traditional keyboard controls.

  15. Simulated radiographic bone and joint modeling from 3D ankle MRI: feasibility and comparison with radiographs and 2D MRI

    Energy Technology Data Exchange (ETDEWEB)

    Nordeck, Shaun M. [University of Texas Southwestern Medical College, Dallas, TX (United States); University of Texas Southwestern Medical Center, Musculoskeletal Radiology, Dallas, TX (United States); Koerper, Conrad E.; Adler, Aaron [University of Texas Southwestern Medical College, Dallas, TX (United States); Malhotra, Vidur; Xi, Yin [University of Texas Southwestern Medical Center, Musculoskeletal Radiology, Dallas, TX (United States); Liu, George T. [University of Texas Southwestern Medical Center, Orthopaedic Surgery, Dallas, TX (United States); Chhabra, Avneesh [University of Texas Southwestern Medical Center, Musculoskeletal Radiology, Dallas, TX (United States); University of Texas Southwestern Medical Center, Orthopaedic Surgery, Dallas, TX (United States)

    2017-05-15

    The purpose of this work is to simulate radiographs from isotropic 3D MRI data, compare relationship of angle and joint space measurements on simulated radiographs with corresponding 2D MRIs and real radiographs (XR), and compare measurement times among the three modalities. Twenty-four consecutive ankles were included, eight males and 16 females, with a mean age of 46 years. Segmented joint models simulating radiographs were created from 3D MRI data sets. Three readers independently performed blinded angle and joint space measurements on the models, corresponding 2D MRIs, and XRs at two time points. Linear mixed models and the intraclass correlation coefficient (ICC) was ascertained, with p values less than 0.05 considered significant. Simulated radiograph models were successfully created in all cases. Good agreement (ICC > 0.65) was noted among all readers across all modalities and among most measurements. Absolute measurement values differed between modalities. Measurement time was significantly greater (p < 0.05) on 2D versus simulated radiographs for most measurements and on XR versus simulated radiographs (p < 0.05) for nearly half the measurements. Simulated radiographs can be successfully generated from 3D MRI data; however, measurements differ. Good inter-reader and moderate-to-good intra-reader reliability was observed and measurements obtained on simulated radiograph models took significantly less time compared to measurements with 2D and generally less time than XR. (orig.)

  16. Space-charge-dominated beam dynamics simulations using the massively parallel processors (MPPs) of the Cray T3D

    International Nuclear Information System (INIS)

    Liu, H.

    1996-01-01

    Computer simulations using the multi-particle code PARMELA with a three-dimensional point-by-point space charge algorithm have turned out to be very helpful in supporting injector commissioning and operations at Thomas Jefferson National Accelerator Facility (Jefferson Lab, formerly called CEBAF). However, this algorithm, which defines a typical N 2 problem in CPU time scaling, is very time-consuming when N, the number of macro-particles, is large. Therefore, it is attractive to use massively parallel processors (MPPs) to speed up the simulations. Motivated by this, the authors modified the space charge subroutine for using the MPPs of the Cray T3D. The techniques used to parallelize and optimize the code on the T3D are discussed in this paper. The performance of the code on the T3D is examined in comparison with a Parallel Vector Processing supercomputer of the Cray C90 and an HP 735/15 high-end workstation

  17. Online 3D Ear Recognition by Combining Global and Local Features.

    Science.gov (United States)

    Liu, Yahui; Zhang, Bob; Lu, Guangming; Zhang, David

    2016-01-01

    The three-dimensional shape of the ear has been proven to be a stable candidate for biometric authentication because of its desirable properties such as universality, uniqueness, and permanence. In this paper, a special laser scanner designed for online three-dimensional ear acquisition was described. Based on the dataset collected by our scanner, two novel feature classes were defined from a three-dimensional ear image: the global feature class (empty centers and angles) and local feature class (points, lines, and areas). These features are extracted and combined in an optimal way for three-dimensional ear recognition. Using a large dataset consisting of 2,000 samples, the experimental results illustrate the effectiveness of fusing global and local features, obtaining an equal error rate of 2.2%.

  18. Online 3D Ear Recognition by Combining Global and Local Features.

    Directory of Open Access Journals (Sweden)

    Yahui Liu

    Full Text Available The three-dimensional shape of the ear has been proven to be a stable candidate for biometric authentication because of its desirable properties such as universality, uniqueness, and permanence. In this paper, a special laser scanner designed for online three-dimensional ear acquisition was described. Based on the dataset collected by our scanner, two novel feature classes were defined from a three-dimensional ear image: the global feature class (empty centers and angles and local feature class (points, lines, and areas. These features are extracted and combined in an optimal way for three-dimensional ear recognition. Using a large dataset consisting of 2,000 samples, the experimental results illustrate the effectiveness of fusing global and local features, obtaining an equal error rate of 2.2%.

  19. High Order Large Eddy Simulation (LES) of Gliding Snake Aerodynamics: Effect of 3D Flow on Gliding Performance

    Science.gov (United States)

    Delorme, Yann; Hassan, Syed Harris; Socha, Jake; Vlachos, Pavlos; Frankel, Steven

    2014-11-01

    Chrysopelea paradisi are snakes that are able to glide over long distances by morphing the cross section of their bodies from circular to a triangular airfoil, and undulating through the air. Snake glide is characterized by relatively low Reynolds number and high angle of attack as well as three dimensional and unsteady flow. Here we study the 3D dynamics of the flow using an in-house high-order large eddy simulation code. The code features a novel multi block immersed boundary method to accurately and efficiently represent the complex snake geometry. We investigate the steady state 3-dimensionality of the flow, especially the wake flow induced by the presence of the snake's body, as well as the vortex-body interaction thought to be responsible for part of the lift enhancement. Numerical predictions of global lift and drag will be compared to experimental measurements, as well as the lift distribution along the body of the snake due to cross sectional variations. Comparisons with previously published 2D results are made to highlight the importance of 3-dimensional effects. Additional efforts are made to quantify properties of the vortex shedding and Dynamic Mode Decomposition (DMD) is used to analyse the main modes responsible for the lift and drag forces.

  20. Best-estimate LOCA simulation in a PWR-W containment building with a detailed 3D GOTHIC model

    International Nuclear Information System (INIS)

    Jimenez, G.; Fernandez-Cosials, K.; Bocanegra, R.; Lopez-Alonso, E.

    2015-01-01

    The design-basis accidents in a PWR-W containment building are usually simulated with a lumped parameter model, normally used for license analysis. Nevertheless, some phenomenology is difficult to be simulated with a lumped model: the condensation rate in each structure, stagnant water areas, temperature in different compartments, sumps and recirculation pumps disabled because of lack of water, etc. Therefore, for the detailed study of the thermal-hydraulic (TH) behaviour in every room of the containment building could be more appropriate to do it with a detailed 3D representation of the containment building geometry. The main objective of this project has been to build a 3D PWR-W containment model with the GOTHIC code to analyze the detailed behavior during a design basis accident. In the process of the 3D GOTHIC model development some previous steps were necessary: a detailed CAD model of the containment, followed by a simplified model adapted to the GOTHIC geometric capabilities. Once the geometry has been adapted to the GOTHIC requirements, the 3D model is created with this information. A design-basis accident has been simulated with the 3D model (LBLOCA), and the local TH behaviour is analysed. The results show that in comparison with a lumped parameter model, high temperatures are reached locally. Nevertheless the average pressure behaviour is found to be similar to that given by a lumped parameter model. The present paper demonstrates that is possible to build a 3D PWR-W model with the GOTHIC code with enough resolution to analyse the TH behaviour in each one of the containment rooms but at the same time with reasonable computing time. Once the GOTHIC model has been created a new road is opened enabling the simulation of other accidents such as MSLB, a SBLOCA or even a long-term SBO sequence. This document is made up of an abstract and the slides of the presentation. (authors)

  1. A parallel overset-curvilinear-immersed boundary framework for simulating complex 3D incompressible flows

    Science.gov (United States)

    Borazjani, Iman; Ge, Liang; Le, Trung; Sotiropoulos, Fotis

    2013-01-01

    We develop an overset-curvilinear immersed boundary (overset-CURVIB) method in a general non-inertial frame of reference to simulate a wide range of challenging biological flow problems. The method incorporates overset-curvilinear grids to efficiently handle multi-connected geometries and increase the resolution locally near immersed boundaries. Complex bodies undergoing arbitrarily large deformations may be embedded within the overset-curvilinear background grid and treated as sharp interfaces using the curvilinear immersed boundary (CURVIB) method (Ge and Sotiropoulos, Journal of Computational Physics, 2007). The incompressible flow equations are formulated in a general non-inertial frame of reference to enhance the overall versatility and efficiency of the numerical approach. Efficient search algorithms to identify areas requiring blanking, donor cells, and interpolation coefficients for constructing the boundary conditions at grid interfaces of the overset grid are developed and implemented using efficient parallel computing communication strategies to transfer information among sub-domains. The governing equations are discretized using a second-order accurate finite-volume approach and integrated in time via an efficient fractional-step method. Various strategies for ensuring globally conservative interpolation at grid interfaces suitable for incompressible flow fractional step methods are implemented and evaluated. The method is verified and validated against experimental data, and its capabilities are demonstrated by simulating the flow past multiple aquatic swimmers and the systolic flow in an anatomic left ventricle with a mechanical heart valve implanted in the aortic position. PMID:23833331

  2. Study of Ion Beam Forming Process in Electric Thruster Using 3D FEM Simulation

    Science.gov (United States)

    Huang, Tao; Jin, Xiaolin; Hu, Quan; Li, Bin; Yang, Zhonghai

    2015-11-01

    There are two algorithms to simulate the process of ion beam forming in electric thruster. The one is electrostatic steady state algorithm. Firstly, an assumptive surface, which is enough far from the accelerator grids, launches the ion beam. Then the current density is calculated by theory formula. Secondly these particles are advanced one by one according to the equations of the motions of ions until they are out of the computational region. Thirdly, the electrostatic potential is recalculated and updated by solving Poisson Equation. At the end, the convergence is tested to determine whether the calculation should continue. The entire process will be repeated until the convergence is reached. Another one is time-depended PIC algorithm. In a global time step, we assumed that some new particles would be produced in the simulation domain and its distribution of position and velocity were certain. All of the particles that are still in the system will be advanced every local time steps. Typically, we set the local time step low enough so that the particle needs to be advanced about five times to move the distance of the edge of the element in which the particle is located.

  3. Precipitation Processes Developed During ARM (1997), TOGA COARE (1992), GATE (1974), SCSMEX (1998), and KWAJEX (1999): Consistent 2D, Semi-3D and 3D Cloud Resolving Model Simulations

    Science.gov (United States)

    Tao, W-K.

    2003-01-01

    Real clouds and cloud systems are inherently three-dimensional (3D). Because of the limitations in computer resources, however, most cloud-resolving models (CRMs) today are still two-dimensional (2D). A few 3D CRMs have been used to study the response of clouds to large-scale forcing. In these 3D simulations, the model domain was small, and the integration time was 6 hours. Only recently have 3D experiments been performed for multi-day periods for tropical cloud systems with large horizontal domains at the National Center for Atmospheric Research (NACAR) and at NASA Goddard Space Flight Center . At Goddard, a 3D Goddard Cumulus Ensemble (GCE) model was used to simulate periods during TOGA COARE, SCSMEX and KWAJEX using 512 by 512 km domain (with 2 km resolution). The results indicate that surface precipitation and latent heating profiles are very similar between the 2D and 3D GCE model simulations. The reason for the strong similarity between the 2D and 3D CRM simulations is that the same observed large-scale advective tendencies of potential temperature, water vapor mixing ratio, and horizontal momentum were used as the main focusing in both the 2D and 3D models. Interestingly, the 2D and 3D versions of the CRM used at CSU showed significant differences in the rainfall and cloud statistics for three ARM cases. The major objectives of this paper are: (1) to assess the performance of the super-parameterization technique, (2) calculate and examine the surface energy (especially radiation) and water budgets, and (3) identify the differences and similarities in the organization and entrainment rates of convection between simulated 2D and 3D cloud systems.

  4. Depth-kymography of vocal fold vibrations : part II. Simulations and direct comparisons with 3D profile measurements

    NARCIS (Netherlands)

    de Mul, Frits F. M.; George, Nibu A.; Qiu, Qingjun; Rakhorst, Gerhard; Schutte, Harm K.

    2009-01-01

    We report novel direct quantitative comparisons between 3D profiling measurements and simulations of human vocal fold vibrations. Until now, in human vocal folds research, only imaging in a horizontal plane was possible. However, for the investigation of several diseases, depth information is

  5. Precision 3d Surface Reconstruction from Lro Nac Images Using Semi-Global Matching with Coupled Epipolar Rectification

    Science.gov (United States)

    Hu, H.; Wu, B.

    2017-07-01

    The Narrow-Angle Camera (NAC) on board the Lunar Reconnaissance Orbiter (LRO) comprises of a pair of closely attached high-resolution push-broom sensors, in order to improve the swath coverage. However, the two image sensors do not share the same lenses and cannot be modelled geometrically using a single physical model. Thus, previous works on dense matching of stereo pairs of NAC images would generally create two to four stereo models, each with an irregular and overlapping region of varying size. Semi-Global Matching (SGM) is a well-known dense matching method and has been widely used for image-based 3D surface reconstruction. SGM is a global matching algorithm relying on global inference in a larger context rather than individual pixels to establish stable correspondences. The stereo configuration of LRO NAC images causes severe problem for image matching methods such as SGM, which emphasizes global matching strategy. Aiming at using SGM for image matching of LRO NAC stereo pairs for precision 3D surface reconstruction, this paper presents a coupled epipolar rectification methods for LRO NAC stereo images, which merges the image pair in the disparity space and in this way, only one stereo model will be estimated. For a stereo pair (four) of NAC images, the method starts with the boresight calibration by finding correspondence in the small overlapping stripe between each pair of NAC images and bundle adjustment of the stereo pair, in order to clean the vertical disparities. Then, the dominate direction of the images are estimated by project the center of the coverage area to the reference image and back-projected to the bounding box plane determined by the image orientation parameters iteratively. The dominate direction will determine an affine model, by which the pair of NAC images are warped onto the object space with a given ground resolution and in the meantime, a mask is produced indicating the owner of each pixel. SGM is then used to generate a disparity

  6. PRECISION 3D SURFACE RECONSTRUCTION FROM LRO NAC IMAGES USING SEMI-GLOBAL MATCHING WITH COUPLED EPIPOLAR RECTIFICATION

    Directory of Open Access Journals (Sweden)

    H. Hu

    2017-07-01

    Full Text Available The Narrow-Angle Camera (NAC on board the Lunar Reconnaissance Orbiter (LRO comprises of a pair of closely attached high-resolution push-broom sensors, in order to improve the swath coverage. However, the two image sensors do not share the same lenses and cannot be modelled geometrically using a single physical model. Thus, previous works on dense matching of stereo pairs of NAC images would generally create two to four stereo models, each with an irregular and overlapping region of varying size. Semi-Global Matching (SGM is a well-known dense matching method and has been widely used for image-based 3D surface reconstruction. SGM is a global matching algorithm relying on global inference in a larger context rather than individual pixels to establish stable correspondences. The stereo configuration of LRO NAC images causes severe problem for image matching methods such as SGM, which emphasizes global matching strategy. Aiming at using SGM for image matching of LRO NAC stereo pairs for precision 3D surface reconstruction, this paper presents a coupled epipolar rectification methods for LRO NAC stereo images, which merges the image pair in the disparity space and in this way, only one stereo model will be estimated. For a stereo pair (four of NAC images, the method starts with the boresight calibration by finding correspondence in the small overlapping stripe between each pair of NAC images and bundle adjustment of the stereo pair, in order to clean the vertical disparities. Then, the dominate direction of the images are estimated by project the center of the coverage area to the reference image and back-projected to the bounding box plane determined by the image orientation parameters iteratively. The dominate direction will determine an affine model, by which the pair of NAC images are warped onto the object space with a given ground resolution and in the meantime, a mask is produced indicating the owner of each pixel. SGM is then used to

  7. Development of a 3-D simulation analysis system for PWR control rod drive mechanism

    International Nuclear Information System (INIS)

    Tanaka, Akio; Futahashi, Kensuke; Takanabe, Kiyoshi; Kurimura, Chikara; Kato, Jungo; Hara, Hidekiyo

    2008-01-01

    A 3-D virtual analysis system to analyze the motion of control rod drive mechanism (CRDM) was developed. The analysis system consists of a 3-D model established as per the actual dimensions and interfaces of CRDM parts and a routine to calculate the forces acting on the mechanism, and was verified by mock-up test using the same equipment as the actual product. The analysis system is useful for functional evaluation in maintenance or to factor out root causes in the case of malfunction of CRDM

  8. Global solutions for 3D nonlocal Gross-Pitaevskii equations with rough data

    Directory of Open Access Journals (Sweden)

    Hartmut Pecher

    2012-10-01

    Full Text Available We study the Cauchy problem for the Gross-Pitaevskii equation with a nonlocal interaction potential of Hartree type in three space dimensions. If the potential is even and positive definite or a positive function and its Fourier transform decays sufficiently rapidly the problem is shown to be globally well-posed for large rough data which not necessarily have finite energy and also in a situation where the energy functional is not positive definite. The proof uses a suitable modification of the I-method.

  9. Representing Objects using Global 3D Relational Features for Recognition Tasks

    DEFF Research Database (Denmark)

    Mustafa, Wail

    2015-01-01

    representations. For representing objects, we derive global descriptors encoding shape using viewpoint-invariant features obtained from multiple sensors observing the scene. Objects are also described using color independently. This allows for combining color and shape when it is required for the task. For more...... robust color description, color calibration is performed. The framework was used in three recognition tasks: object instance recognition, object category recognition, and object spatial relationship recognition. For the object instance recognition task, we present a system that utilizes color and scale...

  10. Precipitation Processes developed during ARM (1997), TOGA COARE (1992), GATE (1974), SCSMEX (1998), and KWAJEX (1999), Consistent 2D, semi-3D and 3D Cloud Resolving Model Simulations

    Science.gov (United States)

    Tao, Wei-Kuo; Hou, A.; Atlas, R.; Starr, D.; Sud, Y.

    2003-01-01

    Real clouds and cloud systems are inherently three-dimensional (3D). Because of the limitations in computer resources, however, most cloud-resolving models (CRMs) today are still two-dimensional (2D). A few 3D CRMs have been used to study the response of clouds to large-scale forcing. In these 3D simulations, the model domain was small, and the integration time was 6 hours. The major objectives of this paper are: (1) to assess the performance of the super-parameterization technique (i.e. is 2D or semi-3D CRM appropriate for the super-parameterization?); (2) calculate and examine the surface energy (especially radiation) and water budgets; (3) identify the differences and similarities in the organization and entrainment rates of convection between simulated 2D and 3D cloud systems.

  11. Effect of microgravity simulation using 3D clinostat on cavendish banana (Musa acuminata AAA Group) ripening process

    Science.gov (United States)

    Dwivany, Fenny Martha; Esyanti, Rizkita R.; Prapaisie, Adeline; Puspa Kirana, Listya; Latief, Chunaeni; Ginaldi, Ari

    2016-11-01

    The objective of the research was to determine the effect of microgravity simulation by 3D clinostat on Cavendish banana (Musa acuminata AAA group) ripening process. In this study, physical, physiological changes as well as genes expression were analysed. The result showed that in microgravity simulation condition ripening process in banana was delayed and the MaACOl, MaACSl and MaACS5 gene expression were affected.

  12. Hybrid mesh generation for the new generation of oil reservoir simulators: 3D extension; Generation de maillage hybride pour les simulateurs de reservoir petrolier de nouvelle generation: extension 3D

    Energy Technology Data Exchange (ETDEWEB)

    Flandrin, N.

    2005-09-15

    During the exploitation of an oil reservoir, it is important to predict the recovery of hydrocarbons and to optimize its production. A better comprehension of the physical phenomena requires to simulate 3D multiphase flows in increasingly complex geological structures. In this thesis, we are interested in this spatial discretization and we propose to extend in 3D the 2D hybrid model proposed by IFP in 1998 that allows to take directly into account in the geometry the radial characteristics of the flows. In these hybrid meshes, the wells and their drainage areas are described by structured radial circular meshes and the reservoirs are represented by structured meshes that can be a non uniform Cartesian grid or a Corner Point Geometry grids. In order to generate a global conforming mesh, unstructured transition meshes based on power diagrams and satisfying finite volume properties are used to connect the structured meshes together. Two methods have been implemented to generate these transition meshes: the first one is based on a Delaunay triangulation, the other one uses a frontal approach. Finally, some criteria are introduced to measure the quality of the transition meshes and optimization procedures are proposed to increase this quality under finite volume properties constraints. (author)

  13. 3-D electromagnetic and thermo-mechanical simulation of a RF cavity

    CERN Document Server

    Launay, F

    2003-01-01

    A 3-D thermo-mechanical study of the edge of entrance blade of IPHI's RFQ was conducted by means of I-DEAS code. The aim is to compare the temperatures reached, the constraints, and the deformations calculated on the basis of RF power density stored on the blade obtained by means of two different electromagnetic computational codes, SOPRANO and MAFIA.

  14. Unidirectional high fiber content composites: Automatic 3D FE model generation and damage simulation

    DEFF Research Database (Denmark)

    Qing, Hai; Mishnaevsky, Leon

    2009-01-01

    A new method and a software code for the automatic generation of 3D micromechanical FE models of unidirectional long-fiber-reinforced composite (LFRC) with high fiber volume fraction with random fiber arrangement are presented. The fiber arrangement in the cross-section is generated through random...

  15. Computational fluid dynamics simulations of blood flow regularized by 3D phase contrast MRI

    DEFF Research Database (Denmark)

    Rispoli, Vinicius C; Nielsen, Jon; Nayak, Krishna S

    2015-01-01

    BACKGROUND: Phase contrast magnetic resonance imaging (PC-MRI) is used clinically for quantitative assessment of cardiovascular flow and function, as it is capable of providing directly-measured 3D velocity maps. Alternatively, vascular flow can be estimated from model-based computation fluid dyn...

  16. Model studies with a 3-d global CTM using ECMWF data

    Energy Technology Data Exchange (ETDEWEB)

    Sundet, Jostein Kandal

    1997-12-31

    It has become evident during the last decades that the large-scale tropospheric distribution of chemical compounds is changing due to man-made emissions. These changes, in turn, lead to changes in the atmospheric oxidation capacity that may significantly affect the environment, such as global warming and increased acid rain. The main objective of this thesis was to use data from a meteorological weather prediction model to drive a global Chemical Tracer (or transport) Model (CTM), the Oslo CTM-2, where the data are generated at the European Centre for Medium-Range Weather Forecasts (ECMWF). It is the kind of data that are taken from the IFS model that is the innovative part of this study. In contrast to other studies, the purpose of the IFS model run is to generate selected data instead of using data from the ECMWF archive. This enabled the extraction of fields useful for atmospheric chemistry studies. The thesis describes the CTM-2 model, presents the data from the IFS model and briefly introduces tropospheric chemistry. Experiments are run to verify the model. The following points for improvements of the model are pointed out: (1) clouds must be included in the photodissociation calculations, (2) better boundary value representing the stratosphere must be obtained for ozone and probably NO and HNO{sub 3} as well, (3) the surface deposition scheme for ozone must be improved, and (4) fluctuations in the chemistry were found and should be eliminated through assessing the fast cycling of OH and HO{sub 2}. Some issues for consideration by the ECMWF are also pointed out. 57 refs., 24 figs., 16 tabs.

  17. 3D VMAT Verification Based on Monte Carlo Log File Simulation with Experimental Feedback from Film Dosimetry.

    Science.gov (United States)

    Barbeiro, A R; Ureba, A; Baeza, J A; Linares, R; Perucha, M; Jiménez-Ortega, E; Velázquez, S; Mateos, J C; Leal, A

    2016-01-01

    A model based on a specific phantom, called QuAArC, has been designed for the evaluation of planning and verification systems of complex radiotherapy treatments, such as volumetric modulated arc therapy (VMAT). This model uses the high accuracy provided by the Monte Carlo (MC) simulation of log files and allows the experimental feedback from the high spatial resolution of films hosted in QuAArC. This cylindrical phantom was specifically designed to host films rolled at different radial distances able to take into account the entrance fluence and the 3D dose distribution. Ionization chamber measurements are also included in the feedback process for absolute dose considerations. In this way, automated MC simulation of treatment log files is implemented to calculate the actual delivery geometries, while the monitor units are experimentally adjusted to reconstruct the dose-volume histogram (DVH) on the patient CT. Prostate and head and neck clinical cases, previously planned with Monaco and Pinnacle treatment planning systems and verified with two different commercial systems (Delta4 and COMPASS), were selected in order to test operational feasibility of the proposed model. The proper operation of the feedback procedure was proved through the achieved high agreement between reconstructed dose distributions and the film measurements (global gamma passing rates > 90% for the 2%/2 mm criteria). The necessary discretization level of the log file for dose calculation and the potential mismatching between calculated control points and detection grid in the verification process were discussed. Besides the effect of dose calculation accuracy of the analytic algorithm implemented in treatment planning systems for a dynamic technique, it was discussed the importance of the detection density level and its location in VMAT specific phantom to obtain a more reliable DVH in the patient CT. The proposed model also showed enough robustness and efficiency to be considered as a pre

  18. A hierarchy of models for simulating experimental results from a 3D heterogeneous porous medium

    Science.gov (United States)

    Vogler, Daniel; Ostvar, Sassan; Paustian, Rebecca; Wood, Brian D.

    2018-04-01

    In this work we examine the dispersion of conservative tracers (bromide and fluorescein) in an experimentally-constructed three-dimensional dual-porosity porous medium. The medium is highly heterogeneous (σY2 = 5.7), and consists of spherical, low-hydraulic-conductivity inclusions embedded in a high-hydraulic-conductivity matrix. The bimodal medium was saturated with tracers, and then flushed with tracer-free fluid while the effluent breakthrough curves were measured. The focus for this work is to examine a hierarchy of four models (in the absence of adjustable parameters) with decreasing complexity to assess their ability to accurately represent the measured breakthrough curves. The most information-rich model was (1) a direct numerical simulation of the system in which the geometry, boundary and initial conditions, and medium properties were fully independently characterized experimentally with high fidelity. The reduced-information models included; (2) a simplified numerical model identical to the fully-resolved direct numerical simulation (DNS) model, but using a domain that was one-tenth the size; (3) an upscaled mobile-immobile model that allowed for a time-dependent mass-transfer coefficient; and, (4) an upscaled mobile-immobile model that assumed a space-time constant mass-transfer coefficient. The results illustrated that all four models provided accurate representations of the experimental breakthrough curves as measured by global RMS error. The primary component of error induced in the upscaled models appeared to arise from the neglect of convection within the inclusions. We discuss the necessity to assign value (via a utility function or other similar method) to outcomes if one is to further select from among model options. Interestingly, these results suggested that the conventional convection-dispersion equation, when applied in a way that resolves the heterogeneities, yields models with high fidelity without requiring the imposition of a more

  19. Preliminary development of a global 3-D magnetohydrodynamic computational model for solar wind-cometary and planetary interactions

    International Nuclear Information System (INIS)

    Stahara, S.S.

    1986-05-01

    This is the final summary report by Resource Management Associates, Inc., of the first year's work under Contract No. NASW-4011 to the National Aeronautics and Space Administration. The work under this initial phase of the contract relates to the preliminary development of a global, 3-D magnetohydrodynamic computational model to quantitatively describe the detailed continuum field and plasma interaction process of the solar wind with cometary and planetary bodies throughout the solar system. The work extends a highly-successful, observationally-verified computational model previously developed by the author, and is appropriate for the global determination of supersonic, super-Alfvenic solar wind flows past planetary obstacles. This report provides a concise description of the problems studied, a summary of all the important research results, and copies of the publications

  20. Fast and accurate global multiphase arrival tracking: the irregular shortest-path method in a 3-D spherical earth model

    Science.gov (United States)

    Huang, Guo-Jiao; Bai, Chao-Ying; Greenhalgh, Stewart

    2013-09-01

    The traditional grid/cell-based wavefront expansion algorithms, such as the shortest path algorithm, can only find the first arrivals or multiply reflected (or mode converted) waves transmitted from subsurface interfaces, but cannot calculate the other later reflections/conversions having a minimax time path. In order to overcome the above limitations, we introduce the concept of a stationary minimax time path of Fermat's Principle into the multistage irregular shortest path method. Here we extend it from Cartesian coordinates for a flat earth model to global ray tracing of multiple phases in a 3-D complex spherical earth model. The ray tracing results for 49 different kinds of crustal, mantle and core phases show that the maximum absolute traveltime error is less than 0.12 s and the average absolute traveltime error is within 0.09 s when compared with the AK135 theoretical traveltime tables for a 1-D reference model. Numerical tests in terms of computational accuracy and CPU time consumption indicate that the new scheme is an accurate, efficient and a practical way to perform 3-D multiphase arrival tracking in regional or global traveltime tomography.

  1. Tropical Oceanic Precipitation Processes Over Warm Pool: 2D and 3D Cloud Resolving Model Simulations

    Science.gov (United States)

    Tao, W.-K.; Johnson, D.; Simpson, J.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Rainfall is a key link in the hydrologic cycle as well as the primary heat source for the atmosphere. The vertical distribution of convective latent-heat release modulates the large-scale circulations of the topics. Furthermore, changes in the moisture distribution at middle and upper levels of the troposphere can affect cloud distributions and cloud liquid water and ice contents. How the incoming solar and outgoing longwave radiation respond to these changes in clouds is a major factor in assessing climate change. Present large-scale weather and climate model simulate processes only crudely, reducing confidence in their predictions on both global and regional scales. One of the most promising methods to test physical parameterizations used in General Circulation Models (GCMs) and climate models is to use field observations together with Cloud Resolving Models (CRMs). The CRMs use more sophisticated and physically realistic parameterizations of cloud microphysical processes, and allow for their complex interactions with solar and infrared radiative transfer processes. The CRMs can reasonably well resolve the evolution, structure, and life cycles of individual clouds and clouds systems. The major objective of this paper is to investigate the latent heating, moisture and momentum budgets associated with several convective systems developed during the TOGA COARE IFA - westerly wind burst event (late December, 1992). The tool for this study is the Goddard Cumulus Ensemble (GCE) model which includes a 3-class ice-phase microphysics scheme.

  2. Design, simulation, fabrication, and preliminary tests of 3D CMS pixel detectors for the super-LHC

    Energy Technology Data Exchange (ETDEWEB)

    Koybasi, Ozhan; /Purdue U.; Bortoletto, Daniela; /Purdue U.; Hansen, Thor-Erik; /SINTEF, Oslo; Kok, Angela; /SINTEF, Oslo; Hansen, Trond Andreas; /SINTEF, Oslo; Lietaer, Nicolas; /SINTEF, Oslo; Jensen, Geir Uri; /SINTEF, Oslo; Summanwar, Anand; /SINTEF, Oslo; Bolla, Gino; /Purdue U.; Kwan, Simon Wing Lok; /Fermilab

    2010-01-01

    The Super-LHC upgrade puts strong demands on the radiation hardness of the innermost tracking detectors of the CMS, which cannot be fulfilled with any conventional planar detector design. The so-called 3D detector architectures, which feature columnar electrodes passing through the substrate thickness, are under investigation as a potential solution for the closest operation points to the beams, where the radiation fluence is estimated to reach 10{sup 16} n{sub eq}/cm{sup 2}. Two different 3D detector designs with CMS pixel readout electronics are being developed and evaluated for their advantages and drawbacks. The fabrication of full-3D active edge CMS pixel devices with p-type substrate has been successfully completed at SINTEF. In this paper, we study the expected post-irradiation behaviors of these devices with simulations and, after a brief description of their fabrication, we report the first leakage current measurement results as performed on wafer.

  3. Global Warming and the Arctic in 3D: A Virtual Globe for Outreach

    Science.gov (United States)

    Manley, W. F.

    2006-12-01

    Virtual Globes provide a new way to capture and inform the public's interest in environmental change. As an example, a recent Google Earth presentation conveyed 'key findings' from the Arctic Climate Impact Assessment (ACIA, 2004) to middle school students during the 2006 INSTAAR/NSIDC Open House at the University of Colorado. The 20-minute demonstration to 180 eighth graders began with an introduction and a view of the Arctic from space, zooming into the North American Arctic, then to a placemark for the first key finding, 'Arctic climate is now warming rapidly and much larger changes are projected'. An embedded link then opened a custom web page, with brief explanatory text, along with an ACIA graphic illustrating the rise in Arctic temperature, global CO2 concentrations, and carbon emissions for the last millennium. The demo continued with an interactive tour of other key findings (Reduced Sea Ice, Changes for Animals, Melting Glaciers, Coastal Erosion, Changes in Vegetation, Melting Permafrost, and others). Each placemark was located somewhat arbitrarily (which may be a concern for some audiences), but the points represented the messages in a geographic sense and enabled a smooth visual tour of the northern latitudes. Each placemark was linked to custom web pages with photos and concise take-home messages. The demo ended with navigation to Colorado, then Boulder, then the middle school that the students attended, all the while speaking to implications as they live their lives locally. The demo piqued the students' curiosity, and in this way better conveyed important messages about the Arctic and climate change. The use of geospatial visualizations for outreach and education appears to be in its infancy, with much potential.

  4. Simulation of a 3D Turbulent Wavy Channel based on the High-order WENO Scheme

    Science.gov (United States)

    Tsai, Bor-Jang; Chou, Chung-Chyi; Tsai, Yeong-Pei; Chuang, Ying Hung

    2018-02-01

    Passive interest turbulent drag reduction, effective means to improve air vehicle fuel consumption costs. Most turbulent problems happening to the nature and engineering applications were exactly the turbulence problem frequently caused by one or more turbulent shear flows. This study was operated with incompressible 3-D channels with cyclic wavy boundary to explore the physical properties of turbulence flow. This research measures the distribution of average velocity, instant flowing field shapes, turbulence and pressure distribution, etc. Furthermore, the systematic computation and analysis for the 3-D flow field was also implemented. It was aimed to clearly understand the turbulence fields formed by wavy boundary of tube flow. The purpose of this research is to obtain systematic structural information about the turbulent flow field and features of the turbulence structure are discussed.

  5. Simulation 3D electromagnetique et thermomecanique d'une cavite RF

    CERN Document Server

    Launay, F

    2003-01-01

    Une etude thermomecanique 3D de l'extremite de lame a l'entree du RFQ d'IPHI a ete menee avec le code I-DEAS. Le but est de comparer les temperatures atteintes, les contraintes et les deformations calculees a partir des densites de puissance RF deposee sur la lame obtenues a partir de deux codes de calcul electromagnetique differents: SOPRANO et MAFIA

  6. Panthere V2: Multipurpose Simulation Software for 3D Dose Rate Calculations

    Science.gov (United States)

    Penessot, Gaël; Bavoil, Éléonore; Wertz, Laurent; Malouch, Fadhel; Visonneau, Thierry; Dubost, Julien

    2017-09-01

    PANTHERE is a multipurpose radiation protection software developed by EDF to calculate gamma dose rates in complex 3D environments. PANTHERE takes a key role in the EDF ALARA process, enabling to predict dose rates and to organize and optimize operations in high radiation environments. PANTHERE is also used for nuclear waste characterization, transport of nuclear materials, etc. It is used in most of the EDF engineering units and their design service providers and industrial partners.

  7. Simulation study of a 3-D device integrating FinFET and UTBFET

    KAUST Repository

    Fahad, Hossain M.

    2015-01-01

    By integrating 3-D nonplanar fins and 2-D ultrathin bodies, wavy FinFETs merge two formerly competing technologies on a silicon-on-insulator platform to deliver enhanced transistor performance compared with conventional trigate FinFETs with unprecedented levels of chip-area efficiency. This makes it suitable for ultralarge-scale integration high-performance logic at and beyond the 10-nm technology node.

  8. 3D atomistic simulation of fatigue behavior of a ductile crack in bcc iron

    Czech Academy of Sciences Publication Activity Database

    Uhnáková, Alena; Machová, Anna; Hora, Petr

    2011-01-01

    Roč. 33, č. 9 (2011), s. 1182-1188 ISSN 0142-1123 R&D Projects: GA ČR(CZ) GAP108/10/0698 Institutional research plan: CEZ:AV0Z20760514 Keywords : 3D molecular dynamics * fatigue * bcc iron * mode I Subject RIV: JG - Metallurgy Impact factor: 1.546, year: 2011 http://www.sciencedirect.com/science/article/pii/S0142112311000600

  9. Comparison between 3D and 1D simulations of a regenerative blower for fuel cell applications

    International Nuclear Information System (INIS)

    Badami, M.; Mura, M.

    2012-01-01

    Highlights: ► A hydrogen recirculation blower for automotive fuel cells applications is studied. ► A 3D CFD analysis has been carried out to better understand the internal flows of the machine. ► The CFD results are compared to a 1D model set up by the authors in previous works. ► The main hypotheses put forward for the theoretical 1D model are compatible with the 3D analysis. - Abstract: A 3D Computational Fluid Dynamics (CFD) analysis has been carried out to better understand the internal fluid dynamics of a regenerative blower used for hydrogen recirculation in a Proton Exchange Membrane (PEM), Fuel Cell (FC) utilized for automotive applications. The obtained results are used to highlight the motion of the fluid in the vanes and in the side channel of the machine and to verify the main hypotheses put forward concerning the theoretical 1D model set up by the authors in previous works on the basis of the momentum exchange theory. Finally, the CFD analysis has been used to point out the effect of the slope of the vanes on the performance of the regenerative blower, and the results have been compared with those obtained using of the 1D model.

  10. Initial progress in the recording of crime scene simulations using 3D laser structured light imagery techniques for law enforcement and forensic applications

    Science.gov (United States)

    Altschuler, Bruce R.; Monson, Keith L.

    1998-03-01

    Representation of crime scenes as virtual reality 3D computer displays promises to become a useful and important tool for law enforcement evaluation and analysis, forensic identification and pathological study and archival presentation during court proceedings. Use of these methods for assessment of evidentiary materials demands complete accuracy of reproduction of the original scene, both in data collection and in its eventual virtual reality representation. The recording of spatially accurate information as soon as possible after first arrival of law enforcement personnel is advantageous for unstable or hazardous crime scenes and reduces the possibility that either inadvertent measurement error or deliberate falsification may occur or be alleged concerning processing of a scene. Detailed measurements and multimedia archiving of critical surface topographical details in a calibrated, uniform, consistent and standardized quantitative 3D coordinate method are needed. These methods would afford professional personnel in initial contact with a crime scene the means for remote, non-contacting, immediate, thorough and unequivocal documentation of the contents of the scene. Measurements of the relative and absolute global positions of object sand victims, and their dispositions within the scene before their relocation and detailed examination, could be made. Resolution must be sufficient to map both small and large objects. Equipment must be able to map regions at varied resolution as collected from different perspectives. Progress is presented in devising methods for collecting and archiving 3D spatial numerical data from crime scenes, sufficient for law enforcement needs, by remote laser structured light and video imagery. Two types of simulation studies were done. One study evaluated the potential of 3D topographic mapping and 3D telepresence using a robotic platform for explosive ordnance disassembly. The second study involved using the laser mapping system on a

  11. SIMULATION-BASED EVALUATION OF LIGHT POSTS AND STREET SIGNS AS 3-D GEOLOCATION TARGETS IN SAR IMAGES

    Directory of Open Access Journals (Sweden)

    S. Auer

    2017-05-01

    Full Text Available The assignment of phase center positions (in 2D or 3D derived from SAR data to physical object is challenging for many man-made structures such as buildings or bridges. In contrast, light poles and traffic signs are promising targets for tasks based on 3-D geolocation as they often show a prominent and spatially isolated appearance. For a detailed understanding of the nature of both targets, this paper presents results of a dedicated simulation case study, which is based on ray tracing methods (simulator RaySAR. For the first time, the appearance of the targets is analyzed in 2D (image plane and 3D space (world coordinates of scene model and reflecting surfaces are identified for related dominant image pixels. The case studies confirms the crucial impact of spatial resolution in the context of light poles and traffic signs and the appropriateness of light poles as target for 3-D geolocation in case of horizontal ground surfaces beneath.

  12. Comparison Between 2-D and 3-D Stiffness Matrix Model Simulation of Sasw Inversion for Pavement Structure

    Directory of Open Access Journals (Sweden)

    Sri Atmaja P. Rosidi

    2007-01-01

    Full Text Available The Spectral Analysis of Surface Wave (SASW method is a non-destructive in situ seismic technique used to assess and evaluate the material stiffness (dynamic elastic modulus and thickness of pavement layers at low strains. These values can be used analytically to calculate load capacities in order to predict the performance of pavement system. The SASW method is based on the dispersion phenomena of Rayleigh waves in layered media. In order to get the actual shear wave velocities, 2-D and 3-D models are used in the simulation of the inversion process for best fitting between theoretical and empirical dispersion curves. The objective of this study is to simulate and compare the 2-D and 3-D model of SASW analysis in the construction of the theoretical dispersion curve for pavement structure evaluation. The result showed that the dispersion curve from the 3-D model was similar with the dispersion curve of the actual pavement profile compared to the 2-D model. The wave velocity profiles also showed that the 3-D model used in the SASW analysis is able to detect all the distinct layers of flexible pavement units.

  13. 3D-printed soft-tissue physical models of renal malignancies for individualized surgical simulation: a feasibility study.

    Science.gov (United States)

    Maddox, Michael M; Feibus, Allison; Liu, James; Wang, Julie; Thomas, Raju; Silberstein, Jonathan L

    2018-03-01

    To construct patient-specific physical three-dimensional (3D) models of renal units with materials that approximates the properties of renal tissue to allow pre-operative and robotic training surgical simulation, 3D physical kidney models were created (3DSystems, Rock Hill, SC) using computerized tomography to segment structures of interest (parenchyma, vasculature, collection system, and tumor). Images were converted to a 3D surface mesh file for fabrication using a multi-jet 3D printer. A novel construction technique was employed to approximate normal renal tissue texture, printers selectively deposited photopolymer material forming the outer shell of the kidney, and subsequently, an agarose gel solution was injected into the inner cavity recreating the spongier renal parenchyma. We constructed seven models of renal units with suspected malignancies. Partial nephrectomy and renorrhaphy were performed on each of the replicas. Subsequently all patients successfully underwent robotic partial nephrectomy. Average tumor diameter was 4.4 cm, warm ischemia time was 25 min, RENAL nephrometry score was 7.4, and surgical margins were negative. A comparison was made between the seven cases and the Tulane Urology prospectively maintained robotic partial nephrectomy database. Patients with surgical models had larger tumors, higher nephrometry score, longer warm ischemic time, fewer positive surgical margins, shorter hospitalization, and fewer post-operative complications; however, the only significant finding was lower estimated blood loss (186 cc vs 236; p = 0.01). In this feasibility study, pre-operative resectable physical 3D models can be constructed and used as patient-specific surgical simulation tools; further study will need to demonstrate if this results in improvement of surgical outcomes and robotic simulation education.

  14. Numerical Simulation of 3D Solid-Liquid Turbulent Flow in a Low Specific Speed Centrifugal Pump: Flow Field Analysis

    Directory of Open Access Journals (Sweden)

    Baocheng Shi

    2014-06-01

    Full Text Available For numerically simulating 3D solid-liquid turbulent flow in low specific speed centrifugal pumps, the iteration convergence problem caused by complex internal structure and high rotational speed of pump is always a problem for numeral simulation researchers. To solve this problem, the combination of three measures of dynamic underrelaxation factor adjustment, step method, and rotational velocity control means according to residual curves trends of operating parameters was used to improve the numerical convergence. Numeral simulation of 3D turbulent flow in a low specific speed solid-liquid centrifugal pump was performed, and the results showed that the improved solution strategy is greatly helpful to the numerical convergence. Moreover, the 3D turbulent flow fields in pumps have been simulated for the bottom ash-particles with the volume fraction of 10%, 20%, and 30% at the same particle diameter of 0.1 mm. The two-phase calculation results are compared with those of single-phase clean water flow. The calculated results gave the main region of the abrasion of the impeller and volute casing and improve the hydraulic design of the impeller in order to decrease the abrasion and increase the service life of the pump.

  15. The simulation methods based on 1D/3D collaborative computing for the vehicle integrated thermal management

    International Nuclear Information System (INIS)

    Lu, Pengyu; Gao, Qing; Wang, Yan

    2016-01-01

    Highlights: • A 1D/3D collaborative computing simulation method for vehicle thermal management. • Analyzing the influence of the thermodynamic systems and the engine compartment geometry on the vehicle performance. • Providing the basis for the matching energy consumptions of thermodynamic systems in the underhood. - Abstract: The vehicle integrated thermal management containing the engine cooling circuit, the air conditioning circuit, the turbocharged inter-cooled circuit, the engine lubrication circuit etc. is the important means of enhancing power performance, promoting economy, saving energy and reducing emission. In this study, a 1D/3D collaborative simulation method is proposed with the engine cooling circuit and air conditioning circuit being the research object. The mathematical characterizations of the multiple thermodynamic systems are achieved by 1D calculation and the underhood structure is described by 3D simulation. Through analyzing the engine compartment integrated heat transfer process, the model of the integrated thermal management system is formed after coupling the cooling circuit and air conditioning circuit. This collaborative simulation method establishes structured correlation of engine-cooling and air conditioning thermal dissipation in the engine compartment, comprehensively analyzing the engine working process and air condition operational process in order to research the interaction effect of them. In the calculation examples, to achieve the integrated optimization of multiple thermal systems design and performance prediction, by describing the influence of system thermomechanical parameters and operating duty to underhood heat transfer process, performance evaluation of the engine cooling circuit and the air conditioning circuit are realized.

  16. 3D micro-crack propagation simulation at enamel/adhesive interface using FE submodeling and element death techniques.

    Science.gov (United States)

    Liu, Heng-Liang; Lin, Chun-Li; Sun, Ming-Tsung; Chang, Yen-Hsiang

    2010-06-01

    This study investigates micro-crack propagation at the enamel/adhesive interface using finite element (FE) submodeling and element death techniques. A three-dimensional (3D) FE macro-model of the enamel/adhesive/ceramic subjected to shear bond testing was generated and analyzed. A 3D micro-model with interfacial bonding structure was constructed at the upper enamel/adhesive interface where the stress concentration was found from the macro-model results. The morphology of this interfacial bonding structure (i.e., resin tag) was assigned based on resin tag geometry and enamel rod arrangement from a scanning electron microscopy micrograph. The boundary conditions for the micro-model were determined from the macro-model results. A custom iterative code combined with the element death technique was used to calculate the micro-crack propagation. Parallel experiments were performed to validate this FE simulation. The stress concentration within the adhesive occurred mainly at the upper corner near the enamel/adhesive interface and the resin tag base. A simulated fracture path was found at the resin tag base along the enamel/adhesive interface. A morphological observation of the fracture patterns obtained from in vitro testing corresponded with the simulation results. This study shows that the FE submodeling and element death techniques could be used to simulate the 3D micro-stress pattern and the crack propagation noted at the enamel/adhesive interface.

  17. GPU based 3D feature profile simulation of high-aspect ratio contact hole etch process under fluorocarbon plasmas

    Science.gov (United States)

    Chun, Poo-Reum; Lee, Se-Ah; Yook, Yeong-Geun; Choi, Kwang-Sung; Cho, Deog-Geun; Yu, Dong-Hun; Chang, Won-Seok; Kwon, Deuk-Chul; Im, Yeon-Ho

    2013-09-01

    Although plasma etch profile simulation has been attracted much interest for developing reliable plasma etching, there still exist big gaps between current research status and predictable modeling due to the inherent complexity of plasma process. As an effort to address this issue, we present 3D feature profile simulation coupled with well-defined plasma-surface kinetic model for silicon dioxide etching process under fluorocarbon plasmas. To capture the realistic plasma surface reaction behaviors, a polymer layer based surface kinetic model was proposed to consider the simultaneous polymer deposition and oxide etching. Finally, the realistic plasma surface model was used for calculation of speed function for 3D topology simulation, which consists of multiple level set based moving algorithm, and ballistic transport module. In addition, the time consumable computations in the ballistic transport calculation were improved drastically by GPU based numerical computation, leading to the real time computation. Finally, we demonstrated that the surface kinetic model could be coupled successfully for 3D etch profile simulations in high-aspect ratio contact hole plasma etching.

  18. Three-dimensional simulation and auto-stereoscopic 3D display of the battlefield environment based on the particle system algorithm

    Science.gov (United States)

    Ning, Jiwei; Sang, Xinzhu; Xing, Shujun; Cui, Huilong; Yan, Binbin; Yu, Chongxiu; Dou, Wenhua; Xiao, Liquan

    2016-10-01

    The army's combat training is very important now, and the simulation of the real battlefield environment is of great significance. Two-dimensional information has been unable to meet the demand at present. With the development of virtual reality technology, three-dimensional (3D) simulation of the battlefield environment is possible. In the simulation of 3D battlefield environment, in addition to the terrain, combat personnel and the combat tool ,the simulation of explosions, fire, smoke and other effects is also very important, since these effects can enhance senses of realism and immersion of the 3D scene. However, these special effects are irregular objects, which make it difficult to simulate with the general geometry. Therefore, the simulation of irregular objects is always a hot and difficult research topic in computer graphics. Here, the particle system algorithm is used for simulating irregular objects. We design the simulation of the explosion, fire, smoke based on the particle system and applied it to the battlefield 3D scene. Besides, the battlefield 3D scene simulation with the glasses-free 3D display is carried out with an algorithm based on GPU 4K super-multiview 3D video real-time transformation method. At the same time, with the human-computer interaction function, we ultimately realized glasses-free 3D display of the simulated more realistic and immersed 3D battlefield environment.

  19. End-to-end simulation of the C-ADS injector Ⅱ with a 3-D field map

    International Nuclear Information System (INIS)

    Wang Zhijun; He Yuan; Li Chao; Wang Wangsheng; Liu Shuhui; Jia Huan; Xu Xianbo; Chen Ximeng

    2013-01-01

    The Injector II, one of the two parallel injectors of the high-current superconducting proton driver linac for the China Accelerator-Driven System (C-ADS) project, is being designed and constructed by the Institute of Modern Physics. At present, the design work for the injector is almost finished. End-to-end simulation has been carried out using the TRACK multiparticle simulation code to check the match between each acceleration section and the performance of the injector as a whole. Moreover, multiparticle simulations with all kinds of errors and misalignments have been performed to define the requirements of each device. The simulation results indicate that the lattice design is robust. In this paper, the results of end-to-end simulation and error simulation with a 3-D field map are presented. (authors)

  20. T-Opt: A 3D Monte Carlo simulation for light delivery design in photodynamic therapy (Conference Presentation)

    Science.gov (United States)

    Honda, Norihiro; Hazama, Hisanao; Awazu, Kunio

    2017-02-01

    The interstitial photodynamic therapy (iPDT) with 5-aminolevulinic acid (5-ALA) is a safe and feasible treatment modality of malignant glioblastoma. In order to cover the tumour volume, the exact position of the light diffusers within the lesion is needed to decide precisely. The aim of this study is the development of evaluation method of treatment volume with 3D Monte Carlo simulation for iPDT using 5-ALA. Monte Carlo simulations of fluence rate were performed using the optical properties of the brain tissue infiltrated by tumor cells and normal tissue. 3-D Monte Carlo simulation was used to calculate the position of the light diffusers within the lesion and light transport. The fluence rate near the diffuser was maximum and decreased exponentially with distance. The simulation can calculate the amount of singlet oxygen generated by PDT. In order to increase the accuracy of simulation results, the parameter for simulation includes the quantum yield of singlet oxygen generation, the accumulated concentration of photosensitizer within tissue, fluence rate, molar extinction coefficient at the wavelength of excitation light. The simulation is useful for evaluation of treatment region of iPDT with 5-ALA.

  1. Co-simulation coupling spectral/finite elements for 3D soil/structure interaction problems

    Science.gov (United States)

    Zuchowski, Loïc; Brun, Michael; De Martin, Florent

    2018-05-01

    The coupling between an implicit finite elements (FE) code and an explicit spectral elements (SE) code has been explored for solving the elastic wave propagation in the case of soil/structure interaction problem. The coupling approach is based on domain decomposition methods in transient dynamics. The spatial coupling at the interface is managed by a standard coupling mortar approach, whereas the time integration is dealt with an hybrid asynchronous time integrator. An external coupling software, handling the interface problem, has been set up in order to couple the FE software Code_Aster with the SE software EFISPEC3D.

  2. System analysis and simulation of airborne scannerless 3D imaging lidar

    Science.gov (United States)

    Guo, Pan; Hao, Qiwei; Chen, Siying

    2009-11-01

    Airborne non-scanned 3D imaging lidar is a recently developed method for remote sensing. The design method and flow of the system parameters round with the spatial resolution are established and explained in detail with examples. An evaluation indicator of data coverage is proposed to optimize the imaging control method. Pixel aliasing in all directions are analyzed, the possible factors cause the aliasing are stated, including the time control error, atmospheric disturbance and platform shake. At last, a parallel data output format is proposed to eliminate the timing mismatch of image data and POS parameters.

  3. USING 3D MODELLING AND NUMERICAL SIMULATION TO OPTIMIZE LARGE WASTEWATER INSTALLATIONS

    Directory of Open Access Journals (Sweden)

    NEDELCUŢ Florin

    2014-09-01

    the evaluating the wastewater treatment efficiency. Another benefit of the CFD analysis was the possibility to visualize the magnitude of the turbulences and large swirls existing inside the clarifiers, as their distribution. With the help of the 3D modelling and CFD we managed to compare two operation cases, in order to better estimate the interval between the required sludge cleaning operations. This more accurate view of operation of final clarifiers, conducted by the CFD analysis presented here, will provide theoretical and technical basis for future proposals when modifying and improving the design of such clarifiers, in the benefit of the designers, engineers and users.

  4. INDUSTRIAL ROBOT ARM SIMULATION SOFTWARE DEVELOPMENT USING JAVA-3D AND MATLAB SIMULINK PROGRAMMING LANGUAGE

    OpenAIRE

    Wirabhuana, Arya

    2011-01-01

    Robot Arms Simulation Software development using Structured Programming Languages, Third Party Language, and Artificial Intelligence Programming Language are the common techniques in simulating robot arms movement. Those three techniques are having its strengths and weaknesses depend on several constraints such as robot type, degree of operation complexity to be simulated, operator skills, and also computer capability. This paper will discuss on Robot Arms Simulation Software (RSS) developmen...

  5. Development and application of a dual RELAP5-3D-based engineering simulator for ABWR

    International Nuclear Information System (INIS)

    Yang, C.-Y.; Liang, Thomas K.S.; Pei, B.S.; Shih, C.K.; Chiang, S.C.; Wang, L.C.

    2009-01-01

    For any innovated plant design, the designed paper plant can be converted into a computer as a digital plant with advanced simulation techniques before being constructed into a real plant. A digital plant, namely engineering simulator, can be applied for: (1) verification of system design and system integration, (2) power test simulation, (3) plant transient and accident analyses, (4) plant abnormal and emergency procedure development and verification, (5) design change verification and analysis, etc. An advanced engineering simulator was successfully developed for the LungMen advanced boiling water reactor (ABWR) plant to support various applications before and after commercial operation. This plant specific engineering simulator was developed based on two separate RELAP5-3D modules synchronized on a commercial simulation platform, namely 3-Key Master. On this advanced LungMen plant simulation (ALPS) platform, major plant dynamics were simulated by two separate RELAP5-3D modules, one for reactor system modeling and the other for balance of plant (BOP) system modeling. Moreover, major control systems as well as emergency core cooling system (ECCS) were all simulated in great detail with built-in tasks of this commercial simulation platform. Different from real time calculation on training simulator, precision of engineering calculation is intentionally kept by synchronizing modules based on the most time-consuming one. During synchronization, each module will check its' own converge criteria in each small time advancement. This plant specific advanced ABWR engineering simulator has been successfully applied on: (1) licensing blowdown analysis of feed water line break (FWLB) for containment design; (2) phenomena investigation of low-pressure ECC injection bypass during FWLB; (3) analysis of FW pump performance during power ascending; (4) verification of plant vendor's pre-test calculations of each start-up test.

  6. A 3D simulation case study of airport air traffic handling

    NARCIS (Netherlands)

    H. de Swaan Arons

    1996-01-01

    textabstractModern Windows-based simulation packages bring simulation within reach of decision-makers. The use of graphics enables the manager to observe an animation of the simulated reality, to focus on the essentials of the model without the need to bother about implementation details. In most

  7. Simulation of mirror surfaces for virtual estimation of visibility lines for 3D motor vehicle collision reconstruction.

    Science.gov (United States)

    Leipner, Anja; Dobler, Erika; Braun, Marcel; Sieberth, Till; Ebert, Lars

    2017-10-01

    3D reconstructions of motor vehicle collisions are used to identify the causes of these events and to identify potential violations of traffic regulations. Thus far, the reconstruction of mirrors has been a problem since they are often based on approximations or inaccurate data. Our aim with this paper was to confirm that structured light scans of a mirror improve the accuracy of simulating the field of view of mirrors. We analyzed the performances of virtual mirror surfaces based on structured light scans using real mirror surfaces and their reflections as references. We used an ATOS GOM III scanner to scan the mirrors and processed the 3D data using Geomagic Wrap. For scene reconstruction and to generate virtual images, we used 3ds Max. We compared the simulated virtual images and photographs of real scenes using Adobe Photoshop. Our results showed that we achieved clear and even mirror results and that the mirrors behaved as expected. The greatest measured deviation between an original photo and the corresponding virtual image was 20 pixels in the transverse direction for an image width of 4256 pixels. We discussed the influences of data processing and alignment of the 3D models on the results. The study was limited to a distance of 1.6m, and the method was not able to simulate an interior mirror. In conclusion, structured light scans of mirror surfaces can be used to simulate virtual mirror surfaces with regard to 3D motor vehicle collision reconstruction. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. PHISICS/RELAP5-3D Adaptive Time-Step Method Demonstrated for the HTTR LOFC#1 Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Robin Ivey [Idaho National Lab. (INL), Idaho Falls, ID (United States); Balestra, Paolo [Univ. of Rome (Italy); Strydom, Gerhard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-05-01

    A collaborative effort between Japan Atomic Energy Agency (JAEA) and Idaho National Laboratory (INL) as part of the Civil Nuclear Energy Working Group is underway to model the high temperature engineering test reactor (HTTR) loss of forced cooling (LOFC) transient that was performed in December 2010. The coupled version of RELAP5-3D, a thermal fluids code, and PHISICS, a neutronics code, were used to model the transient. The focus of this report is to summarize the changes made to the PHISICS-RELAP5-3D code for implementing an adaptive time step methodology into the code for the first time, and to test it using the full HTTR PHISICS/RELAP5-3D model developed by JAEA and INL and the LOFC simulation. Various adaptive schemes are available based on flux or power convergence criteria that allow significantly larger time steps to be taken by the neutronics module. The report includes a description of the HTTR and the associated PHISICS/RELAP5-3D model test results as well as the University of Rome sub-contractor report documenting the adaptive time step theory and methodology implemented in PHISICS/RELAP5-3D. Two versions of the HTTR model were tested using 8 and 26 energy groups. It was found that most of the new adaptive methods lead to significant improvements in the LOFC simulation time required without significant accuracy penalties in the prediction of the fission power and the fuel temperature. In the best performing 8 group model scenarios, a LOFC simulation of 20 hours could be completed in real-time, or even less than real-time, compared with the previous version of the code that completed the same transient 3-8 times slower than real-time. A few of the user choice combinations between the methodologies available and the tolerance settings did however result in unacceptably high errors or insignificant gains in simulation time. The study is concluded with recommendations on which methods to use for this HTTR model. An important caveat is that these findings

  9. Development of tool for simulating the effect of radial electric fields on Ion-Temperature-Gradient modes in 3D configurations

    International Nuclear Information System (INIS)

    Eriksson, Lars

    2003-03-01

    The heat flux level observed in magnetic plasma confinement experiments such as tokamaks is much higher than what can be explained from neoclassical theory. There is a strong interest in the controlled nuclear fusion community to fully understand this phenomenon, called anomalous transport. One idea is that radial electric fields play a key role in the stabilization process of the electrostatic instabilities called micro instabilities that are considered responsible for the anomalous heat flux. This work studies the effect of a static ad-hoc radial electric field on microinstabilities, especially the ion temperature gradient (ITG) driven mode, within the frame of a global 3D gyrokinetic model. This will make it possible to extend the simulations done in tokamaks and helically symmetric systems to fully 313 magnetic configurations. Technically the work consists of extending the 3D gyrokinetic code Euterpe to also include the effect of the drifts induced by an imposed radial electrostatic potential. Simulations are performed in tokamak and helically symmetric configurations. The results indicate that this modified version of Euterpe can be used in studying more complex 3D fusion devices

  10. Ultrasonic simulation - Imagine3D and SimScan: Tools to solve the inverse problem for complex turbine components

    International Nuclear Information System (INIS)

    Mair, H.D.; Ciorau, P.; Owen, D.; Hazelton, T.; Dunning, G.

    2000-01-01

    Two ultrasonic simulation packages: Imagine 3D and SIMSCAN have specifically been developed to solve the inverse problem for blade root and rotor steeple of low-pressure turbine. The software was integrated with the 3D drawing of the inspected parts, and with the dimensions of linear phased-array probes. SIMSCAN simulates the inspection scenario in both optional conditions: defect location and probe movement/refracted angle range. The results are displayed into Imagine 3-D, with a variety of options: rendering, display 1:1, grid, generated UT beam. The results are very useful for procedure developer, training and to optimize the phased-array probe inspection sequence. A spreadsheet is generated to correlate the defect coordinates with UT data (probe position, skew and refracted angle, UT path, and probe movement). The simulation models were validated during experimental work with phased-array systems. The accuracy in probe position is ±1 mm, and the refracted/skew angle is within ±0.5 deg. . Representative examples of phased array focal laws/probe movement for a specific defect location, are also included

  11. 3D Computer graphics simulation to obtain optimal surgical exposure during microvascular decompression of the glossopharyngeal nerve.

    Science.gov (United States)

    Hiraishi, Tetsuya; Matsushima, Toshio; Kawashima, Masatou; Nakahara, Yukiko; Takahashi, Yuichi; Ito, Hiroshi; Oishi, Makoto; Fujii, Yukihiko

    2013-10-01

    The affected artery in glossopharyngeal neuralgia (GPN) is most often the posterior inferior cerebellar artery (PICA) from the caudal side or the anterior inferior cerebellar artery (AICA) from the rostral side. This technical report describes two representative cases of GPN, one with PICA as the affected artery and the other with AICA, and demonstrates the optimal approach for each affected artery. We used 3D computer graphics (3D CG) simulation to consider the ideal transposition of the affected artery in any position and approach. Subsequently, we performed microvascular decompression (MVD) surgery based on this simulation. For PICA, we used the transcondylar fossa approach in the lateral recumbent position, very close to the prone position, with the patient's head tilted anteriorly for caudal transposition of PICA. In contrast, for AICA, we adopted a lateral suboccipital approach with opening of the lateral cerebellomedullary fissure, to visualize better the root entry zone of the glossopharyngeal nerve and to obtain a wide working space in the cerebellomedullary cistern, for rostral transposition of AICA. Both procedures were performed successfully. The best surgical approach for MVD in patients with GPN is contingent on the affected artery--PICA or