Shared Memory Parallelism for 3D Cartesian Discrete Ordinates Solver
NASA Astrophysics Data System (ADS)
Moustafa, Salli; Dutka-Malen, Ivan; Plagne, Laurent; Ponçot, Angélique; Ramet, Pierre
2014-06-01
This paper describes the design and the performance of DOMINO, a 3D Cartesian SN solver that implements two nested levels of parallelism (multicore+SIMD) on shared memory computation nodes. DOMINO is written in C++, a multi-paradigm programming language that enables the use of powerful and generic parallel programming tools such as Intel TBB and Eigen. These two libraries allow us to combine multi-thread parallelism with vector operations in an efficient and yet portable way. As a result, DOMINO can exploit the full power of modern multi-core processors and is able to tackle very large simulations, that usually require large HPC clusters, using a single computing node. For example, DOMINO solves a 3D full core PWR eigenvalue problem involving 26 energy groups, 288 angular directions (S16), 46 × 106 spatial cells and 1 × 1012 DoFs within 11 hours on a single 32-core SMP node. This represents a sustained performance of 235 GFlops and 40:74% of the SMP node peak performance for the DOMINO sweep implementation. The very high Flops/Watt ratio of DOMINO makes it a very interesting building block for a future many-nodes nuclear simulation tool.
Geometrically-compatible 3-D Monte Carlo and discrete-ordinates methods
Morel, J.E.; Wareing, T.A.; McGhee, J.M.; Evans, T.M.
1998-12-31
This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The purpose of this project was two-fold. The first purpose was to develop a deterministic discrete-ordinates neutral-particle transport scheme for unstructured tetrahedral spatial meshes, and implement it in a computer code. The second purpose was to modify the MCNP Monte Carlo radiation transport code to use adjoint solutions from the tetrahedral-mesh discrete-ordinates code to reduce the statistical variance of Monte Carlo solutions via a weight-window approach. The first task has resulted in a deterministic transport code that is much more efficient for modeling complex 3-D geometries than any previously existing deterministic code. The second task has resulted in a powerful new capability for dramatically reducing the cost of difficult 3-D Monte Carlo calculations.
GPU accelerated simulations of 3D deterministic particle transport using discrete ordinates method
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 (S{sub 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.
Quasi-heterogeneous efficient 3-D discrete ordinates CANDU calculations using Attila
Preeti, T.; Rulko, R.
2012-07-01
In this paper, 3-D quasi-heterogeneous large scale parallel Attila calculations of a generic CANDU test problem consisting of 42 complete fuel channels and a perpendicular to fuel reactivity device are presented. The solution method is that of discrete ordinates SN and the computational model is quasi-heterogeneous, i.e. fuel bundle is partially homogenized into five homogeneous rings consistently with the DRAGON code model used by the industry for the incremental cross-section generation. In calculations, the HELIOS-generated 45 macroscopic cross-sections library was used. This approach to CANDU calculations has the following advantages: 1) it allows detailed bundle (and eventually channel) power calculations for each fuel ring in a bundle, 2) it allows the exact reactivity device representation for its precise reactivity worth calculation, and 3) it eliminates the need for incremental cross-sections. Our results are compared to the reference Monte Carlo MCNP solution. In addition, the Attila SN method performance in CANDU calculations characterized by significant up scattering is discussed. (authors)
Li Benwen Tian Shuai; Sun Yasong; Hu, Zhang-Mao
2010-02-20
The Schur-decomposition for three-dimensional matrix equations is developed and used to directly solve the radiative discrete ordinates equations which are discretized by Chebyshev collocation spectral method. Three methods, say, the spectral methods based on 2D and 3D matrix equation solvers individually, and the standard discrete ordinates method, are presented. The numerical results show the good accuracy of spectral method based on direct solvers. The CPU time cost comparisons against the resolutions between these three methods are made using MATLAB and FORTRAN 95 computer languages separately. The results show that the CPU time cost of Chebyshev collocation spectral method with 3D Schur-decomposition solver is the least, and almost only one thirtieth to one fiftieth CPU time is needed when using the spectral method with 3D Schur-decomposition solver compared with the standard discrete ordinates method.
A deterministic discrete ordinates transport proxy application
2014-06-03
Kripke is a simple 3D deterministic discrete ordinates (Sn) particle transport code that maintains the computational load and communications pattern of a real transport code. It is intended to be a research tool to explore different data layouts, new programming paradigms and computer architectures.
NASA Astrophysics Data System (ADS)
Fathi Azarkhavarani, M. E.; Hosseini Abardeh, R.; Rahmani, M.
2016-11-01
In this study a new approach for radiation heat flux calculations by coupling the discrete ordinates method with the Leckner global model is introduced. The aim is to analyze the radiative heat transfer problem within a three-dimensional enclosure filled with non-gray gas mixture of {H}2{O} and {C}{O}2. A computer code developed by this approach is applied to radiative calculations in three groups of well-known test cases published previously; considering homogeneous and inhomogeneous isothermal and non-isothermal participating media. All results are compared with well-known calculations based on statistical narrow band model. Also a new series of predictions for a medium with non-black walls and various mixture of {H}2{O} and {C}{O}2 is performed to demonstrate the applicability of the Leckner model. The effect of different compositions of {H}2{O} and {C}{O}2 on the radiative transfer within modern combustors is also examined. Based on the results obtained, it is believed that the discrete ordinates method coupled with the Leckner global model despite of its inherent simplicity and low computational cost is sufficiently accurate. For its convenient use, this method is suitable for a wide range of engineering calculations of participating media as well as for its link to previously written computational fluid dynamics codes.
NASA Astrophysics Data System (ADS)
Fathi Azarkhavarani, M. E.; Hosseini Abardeh, R.; Rahmani, M.
2015-12-01
In this study a new approach for radiation heat flux calculations by coupling the discrete ordinates method with the Leckner global model is introduced. The aim is to analyze the radiative heat transfer problem within a three-dimensional enclosure filled with non-gray gas mixture of H2O and CO2 . A computer code developed by this approach is applied to radiative calculations in three groups of well-known test cases published previously; considering homogeneous and inhomogeneous isothermal and non-isothermal participating media. All results are compared with well-known calculations based on statistical narrow band model. Also a new series of predictions for a medium with non-black walls and various mixture of H2O and CO2 is performed to demonstrate the applicability of the Leckner model. The effect of different compositions of H2O and CO2 on the radiative transfer within modern combustors is also examined. Based on the results obtained, it is believed that the discrete ordinates method coupled with the Leckner global model despite of its inherent simplicity and low computational cost is sufficiently accurate. For its convenient use, this method is suitable for a wide range of engineering calculations of participating media as well as for its link to previously written computational fluid dynamics codes.
DOS: the discrete-ordinates system. [LMFBR
Rhoades, W. A.; Emmett, M. B.
1982-09-01
The Discrete Ordinates System determines the flux of neutrons or photons due either to fixed sources specified by the user or to sources generated by particle interaction with the problem materials. It also determines numerous secondary results which depend upon flux. Criticality searches can be performed. Numerous input, output, and file manipulation facilities are provided. The DOS driver program reads the problem specification from an input file and calls various program modules into execution as specified by the input file.
Discrete elements for 3D microfluidics.
Bhargava, Krisna C; Thompson, Bryant; Malmstadt, Noah
2014-10-21
Microfluidic systems are rapidly becoming commonplace tools for high-precision materials synthesis, biochemical sample preparation, and biophysical analysis. Typically, microfluidic systems are constructed in monolithic form by means of microfabrication and, increasingly, by additive techniques. These methods restrict the design and assembly of truly complex systems by placing unnecessary emphasis on complete functional integration of operational elements in a planar environment. Here, we present a solution based on discrete elements that liberates designers to build large-scale microfluidic systems in three dimensions that are modular, diverse, and predictable by simple network analysis techniques. We develop a sample library of standardized components and connectors manufactured using stereolithography. We predict and validate the flow characteristics of these individual components to design and construct a tunable concentration gradient generator with a scalable number of parallel outputs. We show that these systems are rapidly reconfigurable by constructing three variations of a device for generating monodisperse microdroplets in two distinct size regimes and in a high-throughput mode by simple replacement of emulsifier subcircuits. Finally, we demonstrate the capability for active process monitoring by constructing an optical sensing element for detecting water droplets in a fluorocarbon stream and quantifying their size and frequency. By moving away from large-scale integration toward standardized discrete elements, we demonstrate the potential to reduce the practice of designing and assembling complex 3D microfluidic circuits to a methodology comparable to that found in the electronics industry.
Automatic Mesh Coarsening for Discrete Ordinates Codes
Turner, Scott A.
1999-03-11
This paper describes the use of a ''mesh potential'' function for automatic coarsening of meshes in discrete ordinates neutral particle transport codes. For many transport calculations, a user may find it helpful to have the code determine a ''good'' neutronics mesh. The complexity of a problem involving millions of mesh cells, dozens of materials, and many energy groups makes it difficult to determine an adequate level of mesh refinement with a minimum number of cells. A method has been implemented in PARTISN (Parallel Time-dependent SN) to calculate a ''mesh potential'' in each original cell of a problem, and use this information to determine the maximum coarseness allowed in the mesh while maintaining accuracy in the solution. Results are presented for a simple x-y-z fuel/control/reflector problem.
Energy-pointwise discrete ordinates transport methods
Williams, M.L.; Asgari, M.; Tashakorri, R.
1997-06-01
A very brief description is given of a one-dimensional code, CENTRM, which computes a detailed, space-dependent flux spectrum in a pointwise-energy representation within the resolved resonance range. The code will become a component in the SCALE system to improve computation of self-shielded cross sections, thereby enhancing the accuracy of codes such as KENO. CENTRM uses discrete-ordinates transport theory with an arbitrary angular quadrature order and a Legendre expansion of scattering anisotropy for moderator materials and heavy nuclides. The CENTRM program provides capability to deterministically compute full energy range, space-dependent angular flux spectra, rigorously accounting for resonance fine-structure and scattering anisotropy effects.
Method for coupling two-dimensional to three-dimensional discrete ordinates calculations
Thompson, J.L.; Emmett, M.B.; Rhoades, W.A.; Dodds, H.L. Jr.
1985-01-01
A three-dimensional (3-D) discrete ordinates transport code, TORT, has been developed at the Oak Ridge National Laboratory for radiation penetration studies. It is not feasible to solve some 3-D penetration problems with TORT, such as a building located a large distance from a point source, because (1) the discretized 3-D problem is simply too big to fit on the computer or (2) the computing time (and corresponding cost) is prohibitive. Fortunately, such problems can be solved with a hybrid approach by coupling a two-dimensional (2-D) description of the point source, which is assumed to be azimuthally symmetric, to a 3-D description of the building, the region of interest. The purpose of this paper is to describe this hybrid methodology along with its implementation and evaluation in the DOTTOR (Discrete Ordinates to Three-dimensional Oak Ridge Transport) code.
Multidimensional electron-photon transport with standard discrete ordinates codes
Drumm, C.R.
1995-12-31
A method is described for generating electron cross sections that are compatible with standard discrete ordinates codes without modification. There are many advantages of using an established discrete ordinates solver, e.g. immediately available adjoint capability. Coupled electron-photon transport capability is needed for many applications, including the modeling of the response of electronics components to space and man-made radiation environments. The cross sections have been successfully used in the DORT, TWODANT and TORT discrete ordinates codes. The cross sections are shown to provide accurate and efficient solutions to certain multidimensional electronphoton transport problems.
Projected discrete ordinates methods for numerical transport problems
Larsen, E.W.
1985-01-01
A class of Projected Discrete-Ordinates (PDO) methods is described for obtaining iterative solutions of discrete-ordinates problems with convergence rates comparable to those observed using Diffusion Synthetic Acceleration (DSA). The spatially discretized PDO solutions are generally not equal to the DSA solutions, but unlike DSA, which requires great care in the use of spatial discretizations to preserve stability, the PDO solutions remain stable and rapidly convergent with essentially arbitrary spatial discretizations. Numerical results are presented which illustrate the rapid convergence and the accuracy of solutions obtained using PDO methods with commonplace differencing methods.
Wareing, T.A.; Parsons, D.K.; Pautz, S.
1997-12-31
Recently, a new state-of-the-art discrete-ordinates code, ATTILA, was developed. ATTILA provides the capabilities to solve geometrically complex 3-D transport problems by using an unstructured tetrahedral mesh. In this paper we describe the application of ATTILA to a 3-D reactor pressure vessel dosimetry problem. We provide numerical results from ATTILA and the Monte Carlo code, MCNP. The results demonstrate the effectiveness and efficiency of ATTILA for such calculations.
DOGS: a collection of graphics for support of discrete ordinates codes
Ingersoll, D.T.; Slater, C.O.
1980-03-01
A collection of computer codes called DOGS (Discrete Ordinates Graphics Support) has been developed to assist in the display and presentation of data generated by commonly used discrete ordinates transport codes. The DOGS codes include: EGAD for plotting two-dimensional geometries, ISOPLOT4 for plotting 2-D fluxes in a contour line fashion, FORM for plotting 2-D fluxes in a 3-D surface fashion, ACTUAL for calculating 2-D activities, TOOTH for calculating and plotting space-energy contributon fluxes, and ASPECT for plotting energy spectra. All of the codes use FIDO input formats and DISSPLA graphics software including the DISSPOP post processors.
Discrete Ordinate Quadrature Selection for Reactor-based Eigenvalue Problems
Jarrell, Joshua J; Evans, Thomas M; Davidson, Gregory G
2013-01-01
In this paper we analyze the effect of various quadrature sets on the eigenvalues of several reactor-based problems, including a two-dimensional (2D) fuel pin, a 2D lattice of fuel pins, and a three-dimensional (3D) reactor core problem. While many quadrature sets have been applied to neutral particle discrete ordinate transport calculations, the Level Symmetric (LS) and the Gauss-Chebyshev product (GC) sets are the most widely used in production-level reactor simulations. Other quadrature sets, such as Quadruple Range (QR) sets, have been shown to be more accurate in shielding applications. In this paper, we compare the LS, GC, QR, and the recently developed linear-discontinuous finite element (LDFE) sets, as well as give a brief overview of other proposed quadrature sets. We show that, for a given number of angles, the QR sets are more accurate than the LS and GC in all types of reactor problems analyzed (2D and 3D). We also show that the LDFE sets are more accurate than the LS and GC sets for these problems. We conclude that, for problems where tens to hundreds of quadrature points (directions) per octant are appropriate, QR sets should regularly be used because they have similar integration properties as the LS and GC sets, have no noticeable impact on the speed of convergence of the solution when compared with other quadrature sets, and yield more accurate results. We note that, for very high-order scattering problems, the QR sets exactly integrate fewer angular flux moments over the unit sphere than the GC sets. The effects of those inexact integrations have yet to be analyzed. We also note that the LDFE sets only exactly integrate the zeroth and first angular flux moments. Pin power comparisons and analyses are not included in this paper and are left for future work.
Discrete Ordinates Solutions for Highly Forward Peaked Scattering
Sanchez, Richard; McCormick, Norman J.
2004-07-15
The limitations of asymptotic methods for numerically solving highly forward peaked scattering (HFPS) problems are reviewed before resorting to a discrete ordinates solution for such problems based on biased angular quadrature formulas to increase the precision of the angular representation and on source evaluation from cell-averaged angular fluxes to reduce memory requirements. Also, a twice-collided source is introduced to avoid numerical representation of singularities in the solution. As an example the propagation and spreading of a collimated particle beam in an HFPS medium has been calculated with a discrete ordinates diamond-differenced numerical solution of the transport equation in two-dimensional curvilinear cylindrical coordinates. The calculation was carried out for a strongly forward peaked Henyey-Greenstein scattering law for which Fokker-Planck asymptotic models are not valid. The results show promise for numerically calculated reference solutions based on accurate spatial representations for checking the accuracy of standard asymptotic models for these types of problems.
Three-dimensional discrete ordinates reactor assembly calculations on GPUs
Evans, Thomas M; Joubert, Wayne; Hamilton, Steven P; Johnson, Seth R; Turner, John A; Davidson, Gregory G; Pandya, Tara M
2015-01-01
In this paper we describe and demonstrate a discrete ordinates sweep algorithm on GPUs. This sweep algorithm is nested within a multilevel comunication-based decomposition based on energy. We demonstrated the effectiveness of this algorithm on detailed three-dimensional critical experiments and PWR lattice problems. For these problems we show improvement factors of 4 6 over conventional communication-based, CPU-only sweeps. These sweep kernel speedups resulted in a factor of 2 total time-to-solution improvement.
Study of Ray Effects in Discrete Ordinates Calculations.
NASA Astrophysics Data System (ADS)
Gomes, Luisa Maria Torres
Ray effects, an inherent problem in the formulation of the discrete ordinates approximation to the transport equation, is studied in this research. In particular, the effectiveness of using Monte Carlo procedures to generate a first collision source or a second collision source is investigated. Monte Carlo procedures provide a general methodology that can be applied to the discrete ordinates solution of complex problems in either two- or three-dimensional geometries, for which ray effects are likely to occur. The Monte Carlo method, which is intrinsically free from ray effects, performs the transport of the source particle to the first collision site. The Monte Carlo estimated uncollided fluxes or first collided fluxes are used to compute the scattering sources in a format suitable for input into the DORT two-dimensional and the TORT three -dimensional discrete ordinates codes. The computational time and precision requirements of the Monte Carlo calculation are analyzed. Also, three procedures for estimating the second collision source with the modified version of MORSE are investigated. The results show that significant improvements are achieved in the solution of the test problems when using the first collision source and that virtual elimination of ray effects is realized when using the second collision source.
Multidimensional electron-photon transport with standard discrete ordinates codes
Drumm, C.R.
1997-04-01
A method is described for generating electron cross sections that are comparable with standard discrete ordinates codes without modification. There are many advantages of using an established discrete ordinates solver, e.g. immediately available adjoint capability. Coupled electron-photon transport capability is needed for many applications, including the modeling of the response of electronics components to space and man-made radiation environments. The cross sections have been successfully used in the DORT, TWODANT and TORT discrete ordinates codes. The cross sections are shown to provide accurate and efficient solutions to certain multidimensional electron-photon transport problems. The key to the method is a simultaneous solution of the continuous-slowing-down (CSD) portion and elastic-scattering portion of the scattering source by the Goudsmit-Saunderson theory. The resulting multigroup-Legendre cross sections are much smaller than the true scattering cross sections that they represent. Under certain conditions, the cross sections are guaranteed positive and converge with a low-order Legendre expansion.
Multidimensional electron-photon transport with standard discrete ordinates codes
Drumm, C.R.
1997-09-01
A method is described for generating electron cross sections that are compatible with standard discrete ordinates codes without modification. There are many advantages to using an established discrete ordinates solver, e.g., immediately available adjoint capability. Coupled electron-photon transport capability is needed for many applications, including the modeling of the response of electronics components to space and synthetic radiation environments. The cross sections have been successfully used in the DORT, TWODANT, and TORT discrete ordinates codes. The cross sections are shown to provide accurate and efficient solutions to certain multidimensional electron-photon transport problems. The key to the method is a simultaneous solution of the continuous-slowing-down and elastic-scattering portions of the scattering source by the Goudsmit-Saunderson theory. The resulting multigroup-Legendre cross sections are much smaller than the true scattering cross sections that they represent. Under certain conditions, the cross sections are guaranteed positive and converge with a low-order Legendre expansion.
DelGrande, J. Mark; Mathews, Kirk A.
2001-09-15
Conventional discrete ordinates transport calculations often produce negative fluxes due to unphysical negative scattering cross sections and/or as artifacts of spatial differencing schemes such as diamond difference. Inherently nonnegative spatial methods, such as the nonlinear, exponential characteristic spatial quadrature, eliminate negative fluxes while providing excellent accuracy, presuming the group-to-group, ordinate-to-ordinate cross sections are all nonnegative. A hybrid approach is introduced in which the flow from spatial cell to spatial cell uses discrete ordinates spatial quadratures, while anisotropic scattering of flux from one energy-angle bin (energy group and discrete element of solid angle) to another such bin is modeled using a Monte Carlo simulation to evaluate the bin-to-bin cross sections. The directional elements tile the sphere of directions; the ordinates for the spatial quadrature are at the centroids of the elements. The method is developed and contrasted with previous schemes for positive cross sections. An algorithm for evaluating the Monte Carlo (MC)-discrete elements (MC-DE) cross sections is described, and some test cases are presented. Transport calculations using MC-DE cross sections are compared with calculations using conventional cross sections and with MCNP calculations. In this testing, the new method is about as accurate as the conventional approach, and often is more accurate. The exponential characteristic spatial quadrature, using the MC-DE cross sections, is shown to provide useful results where linear characteristic and spherical harmonics provide negative scalar fluxes in every cell in a region.
A concurrent, multigroup, discrete ordinates model of neutron transport
Dorr, M.R.; Still, C.H.
1993-10-22
The authors present an algorithm for the concurrent solution of the linear system arising from a multigroup, discrete ordinates model of neutron transport. The target architectures consist of distributed memory computers ranging from workstation clusters to massively parallel computers. Based on an analysis of the memory requirement and floating point complexity of matrix-vector multiplication in the iterative solution of the linear system, the authors propose a data layout and communication strategy designed to achieve scalability with respect to all phase space variables. Numerical results are presented to demonstrate the performance of the algorithm on the nCUBE/2.
3D imaging of nanomaterials by discrete tomography.
Batenburg, K J; Bals, S; Sijbers, J; Kübel, C; Midgley, P A; Hernandez, J C; Kaiser, U; Encina, E R; Coronado, E A; Van Tendeloo, G
2009-05-01
The field of discrete tomography focuses on the reconstruction of samples that consist of only a few different materials. Ideally, a three-dimensional (3D) reconstruction of such a sample should contain only one grey level for each of the compositions in the sample. By exploiting this property in the reconstruction algorithm, either the quality of the reconstruction can be improved significantly, or the number of required projection images can be reduced. The discrete reconstruction typically contains fewer artifacts and does not have to be segmented, as it already contains one grey level for each composition. Recently, a new algorithm, called discrete algebraic reconstruction technique (DART), has been proposed that can be used effectively on experimental electron tomography datasets. In this paper, we propose discrete tomography as a general reconstruction method for electron tomography in materials science. We describe the basic principles of DART and show that it can be applied successfully to three different types of samples, consisting of embedded ErSi(2) nanocrystals, a carbon nanotube grown from a catalyst particle and a single gold nanoparticle, respectively. PMID:19269094
Discrete ordinates methods in xy geometry with spatially varying angular discretization
Bal, G.; Warin, X.
1997-10-01
The efficiency of a new quadrature rule adapted to the numerical resolution of a neutron transport problem in xy geometry is presented based on the use of the discrete ordinates method for the angular variable. The purpose of introducing this quadrature rule is to couple two different angular discretizations used on two nonoverlapping subdomains, which is useful for performing local refinement. This coupling and some numerical results of source problems are presented.
Discrete ordinates with new quadrature sets and modified source conditions
Ganguly, K.; Allen, E.J., Victory, H.D. Jr. )
1989-01-01
A major shortcoming of the discrete ordinates method with the Gauss-Legendre quadrature set is that when the number of secondaries per primary c and the order of approximation N are not too large, all the (N + 1)v (the flux being of the form exp({minus}x/v)) lie in ({minus}1,1). It is known, however, that the largest v{sub j} corresponding to the asymptotic flux is greater than unity. The Legendre polynomial used for obtaining the quadrature set is orthogonal with respect to weight unity in the range ({minus}1,1). However, the Case and Zweifel eigenfunctions derived from the exact solution of one-speed transport theory are orthogonal with respect to a complicated weight function w({mu}) and {mu} in the half-range and full-range cases, respectively. In this paper, the authors have used a set of orthogonal polynomials with respect to w ({mu}) to develop quadrature sets to be used in the discrete ordinates calculation.
Discrete Method of Images for 3D Radio Propagation Modeling
NASA Astrophysics Data System (ADS)
Novak, Roman
2016-09-01
Discretization by rasterization is introduced into the method of images (MI) in the context of 3D deterministic radio propagation modeling as a way to exploit spatial coherence of electromagnetic propagation for fine-grained parallelism. Traditional algebraic treatment of bounding regions and surfaces is replaced by computer graphics rendering of 3D reflections and double refractions while building the image tree. The visibility of reception points and surfaces is also resolved by shader programs. The proposed rasterization is shown to be of comparable run time to that of the fundamentally parallel shooting and bouncing rays. The rasterization does not affect the signal evaluation backtracking step, thus preserving its advantage over the brute force ray-tracing methods in terms of accuracy. Moreover, the rendering resolution may be scaled back for a given level of scenario detail with only marginal impact on the image tree size. This allows selection of scene optimized execution parameters for faster execution, giving the method a competitive edge. The proposed variant of MI can be run on any GPU that supports real-time 3D graphics.
An adaptive mesh refinement algorithm for the discrete ordinates method
Jessee, J.P.; Fiveland, W.A.; Howell, L.H.; Colella, P.; Pember, R.B.
1996-03-01
The discrete ordinates form of the radiative transport equation (RTE) is spatially discretized and solved using an adaptive mesh refinement (AMR) algorithm. This technique permits the local grid refinement to minimize spatial discretization error of the RTE. An error estimator is applied to define regions for local grid refinement; overlapping refined grids are recursively placed in these regions; and the RTE is then solved over the entire domain. The procedure continues until the spatial discretization error has been reduced to a sufficient level. The following aspects of the algorithm are discussed: error estimation, grid generation, communication between refined levels, and solution sequencing. This initial formulation employs the step scheme, and is valid for absorbing and isotopically scattering media in two-dimensional enclosures. The utility of the algorithm is tested by comparing the convergence characteristics and accuracy to those of the standard single-grid algorithm for several benchmark cases. The AMR algorithm provides a reduction in memory requirements and maintains the convergence characteristics of the standard single-grid algorithm; however, the cases illustrate that efficiency gains of the AMR algorithm will not be fully realized until three-dimensional geometries are considered.
3D imaging of semiconductor components by discrete laminography
Batenburg, K. J.; Palenstijn, W. J.; Sijbers, J.
2014-06-19
X-ray laminography is a powerful technique for quality control of semiconductor components. Despite the advantages of nondestructive 3D imaging over 2D techniques based on sectioning, the acquisition time is still a major obstacle for practical use of the technique. In this paper, we consider the application of Discrete Tomography to laminography data, which can potentially reduce the scanning time while still maintaining a high reconstruction quality. By incorporating prior knowledge in the reconstruction algorithm about the materials present in the scanned object, far more accurate reconstructions can be obtained from the same measured data compared to classical reconstruction methods. We present a series of simulation experiments that illustrate the potential of the approach.
On the discrete-ordinates method via Case`s solution
Ganguly, K.; Allen, E.J.; Coskun, E.; Nielsen, S.
1993-07-01
In this paper, we have used Case`s analysis of the neutron transport equation to obtain a new set of quadrature coefficients for the discrete-ordinates method. We perform the transport calculations by this set of quadratures, dependent on the medium. We also use the orthogonality relations in the discrete case to derive the full-range formulation of the half-range problem. This solution can, be profitably used in the new discrete-ordinates method.
Application of the 2-D discrete-ordinates method to multiple scattering of laser radiation
Zardecki, A.; Gerstl, S.A.W.; Embury, J.F.
1983-05-01
The discrete-ordinates finite-element radiation transport code twotran is applied to describe the multiple scattering of a laser beam from a reflecting target. For a model scenario involving a 99% relative humidity rural aerosol we compute the average intensity of the scattered radiation and correction factors to the Beer-Lambert law arising from multiple scattering. As our results indicate, 2-D x-y and r-z geometry modeling can reliably describe a realistic 3-D scenario. Specific results are presented for the two visual ranges of 1.52 and 0.76 km which show that, for sufficiently high aerosol concentrations (e.g., equivalent to V = 0.76 km), the target signature in a distant detector becomes dominated by multiply scattered radiation from interactions of the laser light with the aerosol environment. The merits of the scaling group and the delta-M approximation for the transfer equation are also explored.
Spatial Differencing and Mesh Sensitivity in Two- and Three-Dimensional Discrete Ordinates Codes
C.S. Davidson; C.A. Burre
2002-10-11
Errors due to spatial differencing methods and mesh size in two-dimensional and three-dimensional discrete ordinate solutions of a typical gamma ray shielding problem are illustrated by comparing results from the DORT, TORT, and PARTISN codes. using a model geometry that is typical of spent fuel transfer and storage casks these errors were systematically investigated by varying the mesh size and differencing method. The results of this study show that the fixed-weighted and adaptive weighted diamond differencing methods in 2D problems require mesh intervals of about 0.25 mfp's for reasonable accuracy in deep penetration. The number of mesh cells required for weighted diamond difference methods severely limit the size of 3D problems that can be solved. The linear discontinuous method in PARTISN is shown to maintain numerical accuracy in 3D problems while reducing the overall computational effort by allowing larger mesh intervals. it is also shown that 3D problems exhibit differencing errors that may not readily be inferred from 2D results. Comprehensive displays of the magnitudes of spatial differencing errors in a practical shielding problem provide valuable guidance for the shielding practitioner using today's computational tools.
C5 Benchmark Problem with Discrete Ordinate Radiation Transport Code DENOVO
Yesilyurt, Gokhan; Clarno, Kevin T; Evans, Thomas M; Davidson, Gregory G; Fox, Patricia B
2011-01-01
The C5 benchmark problem proposed by the Organisation for Economic Co-operation and Development/Nuclear Energy Agency was modeled to examine the capabilities of Denovo, a three-dimensional (3-D) parallel discrete ordinates (S{sub N}) radiation transport code, for problems with no spatial homogenization. Denovo uses state-of-the-art numerical methods to obtain accurate solutions to the Boltzmann transport equation. Problems were run in parallel on Jaguar, a high-performance supercomputer located at Oak Ridge National Laboratory. Both the two-dimensional (2-D) and 3-D configurations were analyzed, and the results were compared with the reference MCNP Monte Carlo calculations. For an additional comparison, SCALE/KENO-V.a Monte Carlo solutions were also included. In addition, a sensitivity analysis was performed for the optimal angular quadrature and mesh resolution for both the 2-D and 3-D infinite lattices of UO{sub 2} fuel pin cells. Denovo was verified with the C5 problem. The effective multiplication factors, pin powers, and assembly powers were found to be in good agreement with the reference MCNP and SCALE/KENO-V.a Monte Carlo calculations.
Uniform positive-weight quadratures for discrete ordinate transport calculations
Carew, J.F.; Zamonsky, G.
1999-02-01
Mechanical quadratures that allow systematic improvement and solution convergence are derived for application of the discrete ordinates method to the Boltzmann transport equation. the quadrature directions are arranged on n latitudinal levels, are uniformly distributed over the unit sphere, and have positive weights. Both a uniform and equal-weight quadrature set UE{sub n} and a uniform and Gauss-weight quadrature set UG{sub n} are derived. These quadratures have the advantage over the standard level-symmetric LQ{sub n} quadrature sets in that the weights are positive for all orders, and the solution may be systematically converged by increasing the order of the quadrature set. As the order of the quadrature is increased the points approach a uniform continuous distribution on the unit sphere and the quadrature is invariant with respect to spatial rotations. The numerical integrals converge for continuous functions as the order of the quadrature is increased. Numerical calculations were performed to evaluate the application of the UE{sub n} quadrature set. Comparisons of the exact moments and those calculated using the UE{sub n} quadrature set demonstrate that the moment integrals are performed accurately except for distributions that are very sharply peaked along the direction of the polar axis. A series of DORT transport calculations of the >1-Mev neutron flux for a typical reactor core/pressure vessel geometry were also carried out. These calculations employed the UE{sub n} (n = 6, 10, 12, 18, and 24) quadratures and indicate that the UE{sub n} solutions have converged to within {approximately}0.5%. The UE{sub 24} solutions were also found to be more accurate than the calculations performed with the S{sub 16} level-symmetric quadratures.
Spatial Treatment of the Slab-geometry Discrete Ordinates Equations Using Artificial Neural Networks
Brantley, P S
2001-03-23
An artificial neural network (ANN) method is developed for treating the spatial variable of the one-group slab-geometry discrete ordinates (S{sub N}) equations in a homogeneous medium with linearly anisotropic scattering. This ANN method takes advantage of the function approximation capability of multilayer ANNs. The discrete ordinates angular flux is approximated by a multilayer ANN with a single input representing the spatial variable x and N outputs representing the angular flux in each of the discrete ordinates angular directions. A global objective function is formulated which measures how accurately the output of the ANN approximates the solution of the discrete ordinates equations and boundary conditions at specified spatial points. Minimization of this objective function determines the appropriate values for the parameters of the ANN. Numerical results are presented demonstrating the accuracy of the method for both fixed source and incident angular flux problems.
Coupling of Monte Carlo adjoint leakages with three-dimensional discrete ordinates forward fluences
Slater, C.O.; Lillie, R.A.; Johnson, J.O.; Simpson, D.B.
1998-04-01
A computer code, DRC3, has been developed for coupling Monte Carlo adjoint leakages with three-dimensional discrete ordinates forward fluences in order to solve a special category of geometrically-complex deep penetration shielding problems. The code extends the capabilities of earlier methods that coupled Monte Carlo adjoint leakages with two-dimensional discrete ordinates forward fluences. The problems involve the calculation of fluences and responses in a perturbation to an otherwise simple two- or three-dimensional radiation field. In general, the perturbation complicates the geometry such that it cannot be modeled exactly using any of the discrete ordinates geometry options and thus a direct discrete ordinates solution is not possible. Also, the calculation of radiation transport from the source to the perturbation involves deep penetration. One approach to solving such problems is to perform the calculations in three steps: (1) a forward discrete ordinates calculation, (2) a localized adjoint Monte Carlo calculation, and (3) a coupling of forward fluences from the first calculation with adjoint leakages from the second calculation to obtain the response of interest (fluence, dose, etc.). A description of this approach is presented along with results from test problems used to verify the method. The test problems that were selected could also be solved directly by the discrete ordinates method. The good agreement between the DRC3 results and the direct-solution results verify the correctness of DRC3.
KODELI, IVAN-ALEXANDER
2008-05-22
latest versions available from NEA-DB). o The memory and data management was updated as well as the language level (code was rewritten from Fortran-77 to Fortran-95). SUSD3D is coupled to several discrete‑ordinates codes via binary interface files. SUSD3D can use the flux moment files produced by discrete ordinates codes: ANISN, DORT, TORT, ONEDANT, TWODANT, and THREEDANT. In some of these codes minor modifications are required. Variable dimensions used in the TORT‑DORT system are supported. In 3D analysis the geometry and material composition is taken directly from the TORT produced VARSCL binary file, reducing in this way the user's input to SUSD3D. Multigroup cross‑section sets are read in the GENDF format of the NJOY/GROUPR code system, and the covariance data are expected in the COVFIL format of NJOY/ERRORR or the COVERX format of PUFF‑2. The ZZ‑VITAMIN‑J/COVA cross section covariance matrix library can be used as an alternative to the NJOY code system. The package includes the ANGELO code to produce the covariance data in the required energy structure in the COVFIL format. The following cross section processing modules to be added to the NJOY‑94 code system are included in the package: o ERR34: an extension of the ERRORR module of the NJOY code system for the File‑34 processing. It is used to prepare multigroup SAD cross sections covariance matrices. o GROUPSR: An additional code module for the preparation of partial cross sections for SAD sensitivity analysis. Updated version of the same code from SUSD, extended to the ENDF‑6 format. o SEADR: An additional code module to prepare group covariance matrices for SAD/SED uncertainty analysis.
2008-05-22
are the latest versions available from NEA-DB). o The memory and data management was updated as well as the language level (code was rewritten from Fortran-77 to Fortran-95). SUSD3D is coupled to several discrete‑ordinates codes via binary interface files. SUSD3D can use the flux moment files produced by discrete ordinates codes: ANISN, DORT, TORT, ONEDANT, TWODANT, and THREEDANT. In some of these codes minor modifications are required. Variable dimensions used in the TORT‑DORT system are supported. In 3D analysis the geometry and material composition is taken directly from the TORT produced VARSCL binary file, reducing in this way the user's input to SUSD3D. Multigroup cross‑section sets are read in the GENDF format of the NJOY/GROUPR code system, and the covariance data are expected in the COVFIL format of NJOY/ERRORR or the COVERX format of PUFF‑2. The ZZ‑VITAMIN‑J/COVA cross section covariance matrix library can be used as an alternative to the NJOY code system. The package includes the ANGELO code to produce the covariance data in the required energy structure in the COVFIL format. The following cross section processing modules to be added to the NJOY‑94 code system are included in the package: o ERR34: an extension of the ERRORR module of the NJOY code system for the File‑34 processing. It is used to prepare multigroup SAD cross sections covariance matrices. o GROUPSR: An additional code module for the preparation of partial cross sections for SAD sensitivity analysis. Updated version of the same code from SUSD, extended to the ENDF‑6 format. o SEADR: An additional code module to prepare group covariance matrices for SAD/SED uncertainty analysis.« less
Neutron streaming through shield ducts using a discrete ordinates/Monte Carlo method
Urban, W.T.; Baker, R.S.
1993-08-18
A common problem in shield design is determining the neutron flux that streams through ducts in shields and also that penetrates the shield after having traveled partway down the duct. Obviously the determination of the neutrons that stream down the duct can be computed in a straightforward manner using Monte Carlo techniques. On the other hand those neutrons that must penetrate a significant portion of the shield are more easily handled using discrete ordinates methods. A hybrid discrete ordinates/Monte Carlo cods, TWODANT/MC, which is an extension of the existing discrete ordinates code TWODANT, has been developed at Los Alamos to allow the efficient, accurate treatment of both streaming and deep penetration problems in a single calculation. In this paper we provide examples of the application of TWODANT/MC to typical geometries that are encountered in shield design and compare the results with those obtained using the Los Alamos Monte Carlo code MCNP{sup 3}.
Linking continuum mechanics and 3D discrete dislocation simulations
El-Azab, A. A.; Fivel, M.
1998-10-18
A technique is developed for linking the methods of discrete dislocation dynamics simulation and finite element to treat elasto-plasticity problems. The overall formulation views the plastically deforming crystal as an elastic crystal with continuously changing dislocation microstructure which is tracked by the numerical dynamics simulation. The FEM code needed in this regard is based on linear elasticity only. This formulation presented here is focused on a continuous updating of the outer shape of the crystal, for possible regeneration of the FEM mesh, and adjustment of the surface geometry, in particular the surface normal. The method is expected to be potentially applicable to the nano- indentation experiments, where the zone around the indenter-crystal contact undergoes significant permanent deformation, the rigorous determination of which is very important to the calculation of the indentation print area and in turn, the surface hardness. Furthermore, the technique is expected to account for the plastic history of the surface displacement under the indenter. Other potential applications are mentioned in the text.
Discrete ordinates-Monte Carlo coupling: A comparison of techniques in NERVA radiation analysis
NASA Technical Reports Server (NTRS)
Lindstrom, D. G.; Normand, E.; Wilcox, A. D.
1972-01-01
In the radiation analysis of the NERVA nuclear rocket system, two-dimensional discrete ordinates calculations are sufficient to provide detail in the pressure vessel and reactor assembly. Other parts of the system, however, require three-dimensional Monte Carlo analyses. To use these two methods in a single analysis, a means of coupling was developed whereby the results of a discrete ordinates calculation can be used to produce source data for a Monte Carlo calculation. Several techniques for producing source detail were investigated. Results of calculations on the NERVA system are compared and limitations and advantages of the coupling techniques discussed.
Masiello, E.; Rossi, T.
2013-07-01
In this paper we discuss the latest upgrades of the Boundary Projection Acceleration (BPA) applied to the XYZ transport solver of APOLLO3, namely IDT. The acceleration method is a well-known effective technique for the speed-up of the source iterations of the discrete-ordinates method. The BPA in IDT has been improved in three aspects: the taking into account of the residue on boundary conditions as a boundary source for the acceleration problem, the extension of the method to higher order angular moments in the case of anisotropic scattering and, finally, the application of the method to the multigroup iterations for the acceleration of the fission source and k-effective. The spectrum of the method has been Fourier-analyzed to explore the effectiveness. The 3D mock-up geometry of the ZPPR is presented as final study to test the performances of the acceleration on a realistic whole-core 3D calculation. (authors)
Application of the discrete ordinates method to compute radiant heat loss in a diesel engine
Abraham, J.; Magi, V.
1997-05-09
A three-dimensional model for computing flows, sprays, and combustion in internal combustion engines is modified to include radiant heat loss. Radiant heat loss is computed by solving the radiative transport equation using a discrete ordinates approximation method. Such a method solves the radiative transport equation for a set of discrete directions spanning the range of 4{pi} solid angle. Angular integrals of intensity are discretized by numerical quadrature. The resulting discrete ordinates equations are numerically solved by using a finite volume approach in contravariant formulation. Computations are made with and without radiant heat loss in a diesel engine, and the effects of the radiant heat loss on the computed temperature and NO and soot concentrations are discussed. Inclusion of radiant heat loss reduces the peak temperature by about 10%. As a result, the predicted frozen NO concentrations are found to be lowered. However, the soot concentrations are not significantly altered.
Garcia, R.D.M.; Ono, S.
1999-09-01
An improved implementation of the discrete ordinates method for computing neutral particle transport in ducts is presented. The considered one-dimensional model makes use of two basic functions to represent the transverse and azimuthal dependencies of the particle angular flux in the duct. It is shown that if the problem is decomposed into uncollided and collided problems prior to using the discrete ordinates approximation, the number of ordinates necessary to achieve a desired degree of accuracy in the solution can be greatly reduced, especially for long ducts with significant wall absorption. Further savings in computer time can be attained by employing a composite quadrature based on a (nonstandard) half-range quadrature that can be generated in an effective and efficient way with one of the classical methods in the constructive theory of orthogonal polynomials.
Advanced Algorithms and Automation Tools for Discrete Ordinates Methods in Parallel Environments
Alireza Haghighat
2003-05-07
This final report discusses major accomplishments of a 3-year project under the DOE's NEER Program. The project has developed innovative and automated algorithms, codes, and tools for solving the discrete ordinates particle transport method efficiently in parallel environments. Using a number of benchmark and real-life problems, the performance and accuracy of the new algorithms have been measured and analyzed.
NASA Astrophysics Data System (ADS)
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.
Barichello, L.B.; Siewert, C.E.
1998-09-01
In this work concerning steady-state radiative-transfer calculations in plane-parallel media, the equivalence between the discrete ordinates method and the spherical harmonics method is proved. More specifically, it is shown that for standard radiative-transfer problems without the imposed restriction of azimuthal symmetry the two methods yield identical results for the radiation intensity when the quadrature scheme for the discrete ordinates method is defined by the zeros of the associated Legendre functions and when generalized Mark boundary conditions are used to define the spherical harmonics solution. It is also shown that, with these choices for a quadrature scheme and for the boundary conditions, the two methods can be formulated so as to require the same computational effort. Finally a justification for using the generalized Mark boundary conditions in the spherical harmonics solution is given.
NASA Technical Reports Server (NTRS)
Kato, S.; Smith, G. L.; Barker, H. W.
2001-01-01
An algorithm is developed for the gamma-weighted discrete ordinate two-stream approximation that computes profiles of domain-averaged shortwave irradiances for horizontally inhomogeneous cloudy atmospheres. The algorithm assumes that frequency distributions of cloud optical depth at unresolved scales can be represented by a gamma distribution though it neglects net horizontal transport of radiation. This algorithm is an alternative to the one used in earlier studies that adopted the adding method. At present, only overcast cloudy layers are permitted.
The three-dimensional, discrete ordinates neutral particle transport code TORT: An overview
Azmy, Y.Y.
1996-12-31
The centerpiece of the Discrete Ordinates Oak Ridge System (DOORS), the three-dimensional neutral particle transport code TORT is reviewed. Its most prominent features pertaining to large applications, such as adjustable problem parameters, memory management, and coarse mesh methods, are described. Advanced, state-of-the-art capabilities including acceleration and multiprocessing are summarized here. Future enhancement of existing graphics and visualization tools is briefly presented.
A first collision source method for ATTILA, an unstructured tetrahedral mesh discrete ordinates code
Wareing, T.A.; Morel, J.E.; Parsons, D.K.
1998-12-01
A semi-analytic first collision source method is developed for the transport code, ATTILA, a three-dimensional, unstructured tetrahedral mesh, discrete-ordinates code. This first collision source method is intended to mitigate ray effects due to point sources. The method is third-order accurate, which is the same order of accuracy as the linear-discontinuous spatial differencing scheme used in ATTILA. Numerical results are provided to demonstrate the accuracy and efficiency of the first collision source method.
Brockmann, H.
1999-05-01
In calculating neutral particle transport through elongated voids with the discrete ordinates method, the problem of ray effect may occur if standard angular quadrature sets are used. To mitigate this ray effect, the configuration-factor concept developed in the theory of thermal radiation for calculating the radiation exchange among surfaces is applied here. The common configuration-factor concept is extended in such a way that the angular dependence of the radiation emitted from the surfaces can be considered. The method is applied to regular and annular cylinders with r-z geometry and incorporated into a two-dimensional discrete ordinates transport code. Calculations on a narrow-duct-streaming problem show that the ray effect is strongly reduced by this method. The new method gives results equivalent to or even better than a standard discrete ordinates calculation using a biased angular quadrature set with 166 directions at computing times for one inner iteration that are about a factor of 2 less.
Recommendations for a production discrete-ordinates coupled electron-photon transport capability
Morel, J.E.; Nelson, W.E.
1984-05-01
The purpose of this study was to determine if a production capability for discrete-ordinates coupled electron-photon transport calculations should be developed and, if so, to recommend how it should be done. It is concluded that such a capability should be developed. The purpose of this report is to detail reasons for making these conclusions, and further to make specific recommendations regarding the manner in which this dvelopment should be carried out. The discrete ordinates method is a deterministic method originally developed to solve the neutron transport equation. For this purpose, it has proven to be an accurate and efficient technique. In particular, it has proven to be much more efficient than Monte Carlo methods in one spatial dimension. All current production methods for coupled electron-photon transport calculations are based upon the condensed history method developed by Berger. This method is generally quite expensive for problems of interest to the weapons radiation effects community, even when the problems are limited to one spatial dimension. Thus, routine engineering design calculations involving coupled electron-photon transport must often be performed with rather crude and inaccurate methods due to cost constraints. The existence of this global deficiency is the main motivation for developing a discrete-ordinates coupled electron-photon transport capability. It has the potential of being as accurate as Monte Carlo yet efficient enough to be used in routine engineering design calculations.
L/sub 2/-error estimates for the discrete ordinates method for three-dimensional neutron transport
Asadzadeh, M.
1988-02-01
We prove L/sub 2/-error estimates for the discrete ordinates method for the angular discretization of the three-dimensional neutron transport equation. The analysis is for monoenergetic three-dimensional transport of neutrons in a homogeneous uniform media and isotropic scattering is assumed. A special quadrature rule with relatively uniformly distributed discrete directions is considered.
DeHart, M.D.
1992-12-01
A method for applying the discrete ordinates method for solution of the neutron transport equation in arbitary two-dimensional meshes has been developed. The finite difference approach normally used to approximate spatial derivatives in extrapolating angular fluxes across a cell is replaced by direct solution of the characteristic form of the transport equation for each discrete direction. Thus, computational cells are not restricted to the traditional shape of a mesh element within a given coordinate system. However, in terms of the treatment of energy and angular dependencies, this method resembles traditional discrete ordinates techniques. Using the method developed here, a general two-dimensional space can be approximated by an irregular mesh comprised of arbitrary polygons. The present work makes no assumptions about the orientations or the number of sides in a given cell, and computes all geometric relationships between each set of sides in each cell for each discrete direction. A set of non-reentrant polygons can therefore be used to represent any given two dimensional space. Results for a number of test problems have been compared to solutions obtained from traditional methods, with good agreement. Comparisons include benchmarks against analytical results for problems with simple geometry, as well numerical results obtained from traditional discrete ordinates methods by applying the ANISN and TWOTRAN computer programs. Numerical results were obtained for problems ranging from simple one-dimensional geometry to complicated multidimensional configurations. These results have demonstrated the ability of the developed method to closely approximate complex geometrical configurations and to obtain accurate results for problems that are extremely difficult to model using traditional methods.
Deterministic absorbed dose estimation in computed tomography using a discrete ordinates method
Norris, Edward T.; Liu, Xin; Hsieh, Jiang
2015-07-15
Purpose: Organ dose estimation for a patient undergoing computed tomography (CT) scanning is very important. Although Monte Carlo methods are considered gold-standard in patient dose estimation, the computation time required is formidable for routine clinical calculations. Here, the authors instigate a deterministic method for estimating an absorbed dose more efficiently. Methods: Compared with current Monte Carlo methods, a more efficient approach to estimating the absorbed dose is to solve the linear Boltzmann equation numerically. In this study, an axial CT scan was modeled with a software package, Denovo, which solved the linear Boltzmann equation using the discrete ordinates method. The CT scanning configuration included 16 x-ray source positions, beam collimators, flat filters, and bowtie filters. The phantom was the standard 32 cm CT dose index (CTDI) phantom. Four different Denovo simulations were performed with different simulation parameters, including the number of quadrature sets and the order of Legendre polynomial expansions. A Monte Carlo simulation was also performed for benchmarking the Denovo simulations. A quantitative comparison was made of the simulation results obtained by the Denovo and the Monte Carlo methods. Results: The difference in the simulation results of the discrete ordinates method and those of the Monte Carlo methods was found to be small, with a root-mean-square difference of around 2.4%. It was found that the discrete ordinates method, with a higher order of Legendre polynomial expansions, underestimated the absorbed dose near the center of the phantom (i.e., low dose region). Simulations of the quadrature set 8 and the first order of the Legendre polynomial expansions proved to be the most efficient computation method in the authors’ study. The single-thread computation time of the deterministic simulation of the quadrature set 8 and the first order of the Legendre polynomial expansions was 21 min on a personal computer
Exponential Monte Carlo Convergence of a Three-Dimensional Discrete Ordinates Solution
Favorite, J.A.; Lichtenstein, H.
1999-11-14
Recent work on obtaining exponential convergence for three-dimensional solutions to the spatially and angularly continuous monoenergetic transport equation with isotropic scattering using the reduced source method was promising. The method, however, used two separate estimates of the scalar flux, a Legendre expansion (in the spatial variables) and a quadrature of the angular flux. This introduced an inconsistency that may have lead to some convergence problems. To remove this inconsistency and provide a fairer test of the combined reduced source/Monte Carlo method, the method was applied to estimate the coefficients of a Legendre expansion of the solution of the discrete ordinates equations. In this case, no supplementary approximations were required.
Sebastian Schunert; Yousry Y. Azmy; Damien Fournier
2011-05-01
We present a comprehensive error estimation of four spatial discretization schemes of the two-dimensional Discrete Ordinates (SN) equations on Cartesian grids utilizing a Method of Manufactured Solution (MMS) benchmark suite based on variants of Larsen’s benchmark featuring different orders of smoothness of the underlying exact solution. The considered spatial discretization schemes include the arbitrarily high order transport methods of the nodal (AHOTN) and characteristic (AHOTC) types, the discontinuous Galerkin Finite Element method (DGFEM) and the recently proposed higher order diamond difference method (HODD) of spatial expansion orders 0 through 3. While AHOTN and AHOTC rely on approximate analytical solutions of the transport equation within a mesh cell, DGFEM and HODD utilize a polynomial expansion to mimick the angular flux profile across each mesh cell. Intuitively, due to the higher degree of analyticity, we expect AHOTN and AHOTC to feature superior accuracy compared with DGFEM and HODD, but at the price of potentially longer grind times and numerical instabilities. The latter disadvantages can result from the presence of exponential terms evaluated at the cell optical thickness that arise from the semianalytical solution process. This work quantifies the order of accuracy and the magnitude of the error of all four discretization methods for different optical thicknesses, scattering ratios and degrees of smoothness of the underlying exact solutions in order to verify or contradict the aforementioned intuitive expectation.
Wang, Dafang; Kirby, Robert M; Johnson, Chris R
2011-06-01
We consider the inverse electrocardiographic problem of computing epicardial potentials from a body-surface potential map. We study how to improve numerical approximation of the inverse problem when the finite-element method is used. Being ill-posed, the inverse problem requires different discretization strategies from its corresponding forward problem. We propose refinement guidelines that specifically address the ill-posedness of the problem. The resulting guidelines necessitate the use of hybrid finite elements composed of tetrahedra and prism elements. Also, in order to maintain consistent numerical quality when the inverse problem is discretized into different scales, we propose a new family of regularizers using the variational principle underlying finite-element methods. These variational-formed regularizers serve as an alternative to the traditional Tikhonov regularizers, but preserves the L(2) norm and thereby achieves consistent regularization in multiscale simulations. The variational formulation also enables a simple construction of the discrete gradient operator over irregular meshes, which is difficult to define in traditional discretization schemes. We validated our hybrid element technique and the variational regularizers by simulations on a realistic 3-D torso/heart model with empirical heart data. Results show that discretization based on our proposed strategies mitigates the ill-conditioning and improves the inverse solution, and that the variational formulation may benefit a broader range of potential-based bioelectric problems.
Tofsted, D H; O'Brien, S G
1998-11-20
A technique is developed to model radiative transfer in three-dimensional natural clouds with a standard discrete ordinates finite-element method modified to evaluate cell-surface-averaged radiances. A log-least-squares-based scale transformation is used to improve the discrete phase-function model. We handle dense media by assuming constant diffuse radiances over input faces to cubic cells, allowing analytical forms for transmittance factors. Transmission equations are combined with diffuse volumetric single-scattering calculations to support evaluations of cell energy balance. Energy not accounted for volumetrically is treated with surface-based effects. Results produced show accurate flux computations at over 30 optical depths per modeled cell. Comparisons with nonuniform cloud Monte Carlo calculations show less than 1% rms error and correlations greater than 0.999 for cases in which cloud-density fluctuations are resolved.
Two-dimensional HID light source radiative transfer using discrete ordinates method
NASA Astrophysics Data System (ADS)
Ghrib, Basma; Bouaoun, Mohamed; Elloumi, Hatem
2016-08-01
This paper shows the implementation of the Discrete Ordinates Method for handling radiation problems in High Intensity Discharge (HID) lamps. Therefore, we start with presenting this rigorous method for treatment of radiation transfer in a two-dimensional, axisymmetric HID lamp. Furthermore, the finite volume method is used for the spatial discretization of the Radiative Transfer Equation. The atom and electron densities were calculated using temperature profiles established by a 2D semi-implicit finite-element scheme for the solution of conservation equations relative to energy, momentum, and mass. Spectral intensities as a function of position and direction are first calculated, and then axial and radial radiative fluxes are evaluated as well as the net emission coefficient. The results are given for a HID mercury lamp on a line-by-line basis. A particular attention is paid on the 253.7 nm resonance and 546.1 nm green lines.
NASA Technical Reports Server (NTRS)
Chai, John C.; Lee, Haeok S.; Patankar, Suhas V.
1993-01-01
Three popular spatial differencing schemes for the discrete ordinates method are examined for two-dimensional Cartesian coordinates system. These are a positive, the step, and the diamond schemes. Contrary to the common belief that negative intensities will not occur when fine spatial discretization is used with the diamond scheme, under certain conditions, the diamond scheme will produce negative intensities irrespective of the number of control volums employed. The positive scheme can produce physically unrealistic trends. The diamond and positive schemes are also capable of producing physically unrealistic overshoots. In absorbing-emitting or absorbing-emitting-scattering media, grid refinement can result in negative intensities when the diamond or positive scheme is used.
NASA Technical Reports Server (NTRS)
Korkin, Sergey V.; Lyapustin, Alexei I.; Rozanov, Vladimir V.
2012-01-01
A numerical accuracy analysis of the radiative transfer equation (RTE) solution based on separation of the diffuse light field into anisotropic and smooth parts is presented. The analysis uses three different algorithms based on the discrete ordinate method (DOM). Two methods, DOMAS and DOM2+, that do not use the truncation of the phase function, are compared against the TMS-method. DOMAS and DOM2+ use the Small-Angle Modification of RTE and the single scattering term, respectively, as an anisotropic part. The TMS method uses Delta-M method for truncation of the phase function along with the single scattering correction. For reference, a standard discrete ordinate method, DOM, is also included in analysis. The obtained results for cases with high scattering anisotropy show that at low number of streams (16, 32) only DOMAS provides an accurate solution in the aureole area. Outside of the aureole, the convergence and accuracy of DOMAS, and TMS is found to be approximately similar: DOMAS was found more accurate in cases with coarse aerosol and liquid water cloud models, except low optical depth, while the TMS showed better results in case of ice cloud.
Discrete ordinates transport methods for problems with highly forward-peaked scattering
Pautz, S.D.
1998-04-01
The author examines the solutions of the discrete ordinates (S{sub N}) method for problems with highly forward-peaked scattering kernels. He derives conditions necessary to obtain reasonable solutions in a certain forward-peaked limit, the Fokker-Planck (FP) limit. He also analyzes the acceleration of the iterative solution of such problems and offer improvements to it. He extends the analytic Fokker-Planck limit analysis to the S{sub N} equations. This analysis shows that in this asymptotic limit the S{sub N} solution satisfies a pseudospectral discretization of the FP equation, provided that the scattering term is handled in a certain way (which he describes) and that the analytic transport solution satisfies an analytic FP equation. Similar analyses of various spatially discretized S{sub N} equations reveal that they too produce solutions that satisfy discrete FP equations, given the same provisions. Numerical results agree with these theoretical predictions. He defines a multidimensional angular multigrid (ANMG) method to accelerate the iterative solution of highly forward-peaked problems. The analyses show that a straightforward application of this scheme is subject to high-frequency instabilities. However, by applying a diffusive filter to the ANMG corrections he is able to stabilize this method. Fourier analyses of model problems show that the resulting method is effective at accelerating the convergence rate when the scattering is forward-peaked. The numerical results demonstrate that these analyses are good predictors of the actual performance of the ANMG method.
Discrete ordinates transport methods for problems with highly forward-peaked scattering
NASA Astrophysics Data System (ADS)
Pautz, Shawn Daniel
1998-10-01
We examine the solutions of the discrete ordinates (SN) method for problems with highly forward- peaked scattering kernels. We derive conditions necessary to obtain reasonable solutions in a certain forward- peaked limit, the Fokker-Planck (FP) limit. We also analyze the acceleration of the iterative solution of such problems and offer improvements to it. We extend the analytic Fokker-Planck limit analysis to the SN equations. This analysis shows that in this asymptotic limit the SN solution satisfies a pseudospectral discretization of the FP equation, provided that the scattering term is handled in a certain way (which we describe) and that the analytic transport solution satisfies an analytic FP equation. Similar analyses of various spatially discretized SN equations reveal that they too produce solutions that satisfy discrete FP equations, given the same provisions. Numerical results agree with these theoretical predictions. We define a multidimensional angular multigrid (ANMG) method to accelerate the iterative solution of highly forward-peaked problems. Our analyses show that a straightforward application of this scheme is subject to high-frequency instabilities. However, by applying a diffusive filter to the ANMG corrections we are able to stabilize this method. Fourier analyses of model problems show that the resulting method is effective at accelerating the convergence rate when the scattering is forward-peaked. Our numerical results demonstrate that these analyses are good predictors of the actual performance of the ANMG method.
Zhang, Shan-shan; Su, Rong-guo; Duan, Ya-li; Song, Zhi-jie; Wang, Xiu-lin
2011-03-01
The present research was targeted to develop a fluorescence analyser for phytoplankton population which uses a series of LEDs as the light source. So the 3D discrete fluorescence spectra with 12 excitation wavelengths (400, 430, 450, 460,470, 490, 500, 510, 525, 550, 570 and 590 nm) were determined by fluorescence spectrophotometer for 43 phytoplankton species. Then, the wavelet, Daubechies-7 (Db7), and Bayes Classifier were applied to extract the characteristics for each classes from the 3D discrete fluorescence spectra. Lastly, the fluorescence differentiation method for phytoplankton populations was established by multivariate linear regression and non-negative least squares, which could differentiate phytoplankton populations at the levels of both divisions and genus. This method was tested: for simulatively mixed samples(the dominant species accounted for 70%, 80%, 90% and 100% of the gross biomass, respectively) from 32 red tide algal species, and the correct discrimination rates at the level of genus were 67.5%, 75.8%, 81.4% and 79.4%, respectively. For simulatively mixed samples (the dominant divisions algae accounted for 50%, 75% and 100% of the gross biomass, respectively) from 43 algal species, the discrimination rates at the level of division were 95.2%, 99.7% and 91.9% with average relative content of 38.1%, 63.2% and 90.5%, respectively. PMID:21595229
Daskalov, G.M.; Baker, R.S.; Little, R.C.; Rogers, D.W.O.; Williamson, J.F.
2000-02-01
The DANTSYS discrete ordinates computer code system is applied to quantitative estimation of water kerma rate distributions in the vicinity of discrete photon sources with energies in the 20- to 800-keV range in two-dimensional cylindrical r-z geometry. Unencapsulated sources immersed in cylindrical water phantoms of 40-cm diameter and 40-cm height are modeled in either homogeneous phantoms or shielded by Ti, Fe, and Pb filters with thicknesses of 1 and 2 mean free paths. The obtained dose results are compared with corresponding photon Monte Carlo simulations. A 210-group photon cross-section library for applications in this energy range is developed and applied, together with a general-purpose 42-group library developed at Los Alamos National Laboratory, for DANTSYS calculations. The accuracy of DANTSYS with the 42-group library relative to Monte Carlo exhibits large pointwise fluctuations from {minus}42 to +84%. The major cause for the observed discrepancies is determined to be the inadequacy of the weighting function used for the 42-group library derivation. DANTSYS simulations with a finer 210-group library show excellent accuracy on and off the source transverse plane relative to Monte Carlo kerma calculations, varying from {minus}4.9 to 3.7%. The P{sub 3} Legendre polynomial expansion of the angular scattering function is shown to be sufficient for accurate calculations. The results demonstrate that DANTSYS is capable of calculating photon doses in very good agreement with Monte Carlo and that the multigroup cross-section library and efficient techniques for mitigation of ray effects are critical for accurate discrete ordinates implementation.
NASA Technical Reports Server (NTRS)
Jensen, K. A.; Ripoll, J.-F.; Wray, A. A.; Joseph, D.; ElHafi, M.
2004-01-01
Five computational methods for solution of the radiative transfer equation in an absorbing-emitting and non-scattering gray medium were compared on a 2 m JP-8 pool fire. The temperature and absorption coefficient fields were taken from a synthetic fire due to the lack of a complete set of experimental data for fires of this size. These quantities were generated by a code that has been shown to agree well with the limited quantity of relevant data in the literature. Reference solutions to the governing equation were determined using the Monte Carlo method and a ray tracing scheme with high angular resolution. Solutions using the discrete transfer method, the discrete ordinate method (DOM) with both S(sub 4) and LC(sub 11) quadratures, and moment model using the M(sub 1) closure were compared to the reference solutions in both isotropic and anisotropic regions of the computational domain. DOM LC(sub 11) is shown to be the more accurate than the commonly used S(sub 4) quadrature technique, especially in anisotropic regions of the fire domain. This represents the first study where the M(sub 1) method was applied to a combustion problem occurring in a complex three-dimensional geometry. The M(sub 1) results agree well with other solution techniques, which is encouraging for future applications to similar problems since it is computationally the least expensive solution technique. Moreover, M(sub 1) results are comparable to DOM S(sub 4).
Boltzmann-Fokker-Planck calculations using standard discrete-ordinates codes
Morel, J.E.
1987-01-01
The Boltzmann-Fokker-Planck (BFP) equation can be used to describe both neutral and charged-particle transport. Over the past several years, the author and several collaborators have developed methods for representing Fokker-Planck operators with standard multigroup-Legendre cross-section data. When these data are input to a standard S/sub n/ code such as ONETRAN, the code actually solves the Boltzmann-Fokker-Planck equation rather than the Boltzmann equation. This is achieved wihout any modification to the S/sub n/ codes. Because BFP calculations can be more demanding from a numerical viewpoint than standard neutronics calculations, we have found it useful to implement new quadrature methods ad convergence acceleration methods in the standard discrete-ordinates code, ONETRAN. We discuss our BFP cross-section representation techniques, our improved quadrature and acceleration techniques, and present results from BFP coupled electron-photon transport calculations performed with ONETRAN. 19 refs., 7 figs.
Analysis of Massively Parallel Discrete-Ordinates Transport Sweep Algorithms with Collisions
Bailey, T S; Falgout, R D
2008-10-14
We present theoretical scaling models for a variety of discrete-ordinates sweep algorithms. In these models, we pay particular attention to the way each algorithm handles collisions. A collision is defined as a processor having multiple angles with ready to be swept during one stage of the sweep. The models also take into account how subdomains are assigned to processors and how angles are grouped during the sweep. We describe a data driven algorithm that resolves collisions efficiently during the sweep as well as other algorithms that have been designed to avoid collisions completely. Our models are validated using the ARGES and AMTRAN transport codes. We then use the models to study and predict scaling trends in all of the sweep algorithms.
The method of lines solution of discrete ordinates method for non-grey media
NASA Astrophysics Data System (ADS)
Çayan, Fatma Nihan; Selçuk, Nevin
2007-03-01
A radiation code based on method of lines (MOL) solution of discrete ordinates method (DOM) for radiative heat transfer in non-grey absorbing emitting media was developed by incorporation of a gas spectral radiative property model, namely wide band correlated-k (WBCK) model, which is compatible with MOL solution of DOM. Predictive accuracy of the code was evaluated by applying it to 1-D parallel plate and 2-D axisymmetric cylindrical enclosure problems containing absorbing emitting medium and benchmarking its predictions against line-by-line solutions available in the literature. Comparisons reveal that MOL solution of DOM with WBCK model produces accurate results for radiative heat fluxes and source terms and can be used with confidence in conjunction with computational fluid dynamics codes based on the same approach.
Discrete ordinate theory of radiative transfer. 2: Scattering from maritime haze
NASA Technical Reports Server (NTRS)
Kattawar, G. W.; Plass, G. N.; Catchings, F. E.
1971-01-01
Discrete ordinate theory was used to calculate the reflected and transmitted radiance of photons which have interacted with plane parallel maritime haze layers. The results are presented for three solar zenith angles, three values of the surface albedo, and a range of optical thicknesses from very thin to very thick. The diffuse flux at the lower boundary and the cloud albedo were tabulated. The forward peak and other features in the single scattered phase function caused the radiance in many cases to be very different from that for Rayleigh scattering. The variation of the radiance with both the zenith or nadir angle and the azimuthal angle is more marked, and the relative limb darkening under very thick layers is greater, for haze than for Rayleigh scattering. The downward diffuse flux at the lower boundary for A = O is always greater and the cloud albedo is always less for haze than for Rayleigh layers.
Animation Strategies for Smooth Transformations Between Discrete Lods of 3d Building Models
NASA Astrophysics Data System (ADS)
Kada, Martin; Wichmann, Andreas; Filippovska, Yevgeniya; Hermes, Tobias
2016-06-01
The cartographic 3D visualization of urban areas has experienced tremendous progress over the last years. An increasing number of applications operate interactively in real-time and thus require advanced techniques to improve the quality and time response of dynamic scenes. The main focus of this article concentrates on the discussion of strategies for smooth transformation between two discrete levels of detail (LOD) of 3D building models that are represented as restricted triangle meshes. Because the operation order determines the geometrical and topological properties of the transformation process as well as its visual perception by a human viewer, three different strategies are proposed and subsequently analyzed. The simplest one orders transformation operations by the length of the edges to be collapsed, while the other two strategies introduce a general transformation direction in the form of a moving plane. This plane either pushes the nodes that need to be removed, e.g. during the transformation of a detailed LOD model to a coarser one, towards the main building body, or triggers the edge collapse operations used as transformation paths for the cartographic generalization.
Denovo--A New Three-Dimensional Parallel Discrete Ordinates Code in SCALE
Evans, Thomas M; Stafford, Alissa; Clarno, Kevin T
2010-01-01
Denovo is a new, three-dimensional, discrete ordinates (SN) transport code that uses state-of-the-art solution methods to obtain accurate solutions to the Boltzmann transport equation. Denovo uses the Koch-Baker-Alcouffe parallel sweep algorithm to obtain high parallel efficiency on O(100) processors on XYZ orthogonal meshes. As opposed to traditional SN codes that use source iteration, Denovo uses nonstationary Krylov methods to solve the within-group equations. Krylov methods are far more efficient than stationary schemes. Additionally, classic acceleration schemes (diffusion synthetic acceleration) do not suffer stability problems when used as a preconditioner to a Krylov solver. Denovo's generic programming framework allows multiple spatial discretization schemes and solution methodologies. Denovo currently provides diamond-difference, theta-weighted diamond-difference, linear-discontinuous finite element, trilinear-discontinuous finite element, and step characteristics spatial differencing schemes. Also, users have the option of running traditional source iteration instead of Krylov iteration. Multigroup upscatter problems can be solved using Gauss-Seidel iteration with transport, two-grid acceleration. A parallel first-collision source is also available. Denovo solutions to the Kobayashi benchmarks are in excellent agreement with published results. Parallel performance shows excellent weak scaling up to 20000 cores and good scaling up to 40000 cores.
DOXCY - A discrete ordinates approximation of neutron transport in heterogeneous rod lattices
Martens, H.D.; Stegemann, D.
1987-08-01
For calculating the fine flux distribution in heterogeneous fuel rod lattices, an exact treatment of the geometry and the use of a high-order approximation of the transport theory is needed. For this purpose, a discrete ordinates solution of the neutron transport equation for mixed geometry has been developed. The discretization of the space is performed in separate one-dimensional cylindrical coordinate systems, imbedded in a two-dimensional rectangular mesh grid. The geometrical link between the cylindrical and the rectangular systems is achieved by approximating the outer circle of each cylindrical system by a polygon with side numbers greater than or equal to8. Thus, each cylindrical geometry is enclosed in a two-dimensional mesh grid consisting of rectangles, trapeziums, and triangles. Because of the different orientation of the angular segmentation in XY and R coordinates, transfer coefficients are derived to calculate the directional flux distribution on the boundary between both systems. A special set of equal-weighted quadrature coefficients (EQ/sub n/) is used to get transfer coefficients, providing a fast and accurate solution. The method is realized in a program called DOXCY, which runs within the nuclear program system RSYST. The program is verified on selected benchmark problems. The numerical results are given, showing the advantage and limits of the method.
NASA Astrophysics Data System (ADS)
Suriano, Mark Allen
2001-07-01
Accurate, reliable, and robust discrete neutral particle radiation transport codes are needed in order to perform realistic 3D engineering calculations. Current neutron transport codes use low order spatial quadratures that are inaccurate unless a highly refined spatial mesh is used. In this work various higher order characteristic spatial quadratures are derived, implemented, and tested. Regular meshes of rectangular (2D) and of rectangular parallelepiped (boxoid) cells are supported. Short characteristic (linear characteristic [LC] and exponential characteristic [EC]) methods are compared with the corresponding independent characteristic (ILC and IEC) methods. The latter readily provide for plane parallel implementation. All transport results were benchmarked against Monte Carlo calculations. The diamond difference (DD) method was also tested and compared to the characteristic spatial quadratures. IEC and EC were found to be robust, reliable, and accurate for thin, intermediate, and optically thick cells. LC was robust, reliable, and accurate for cells of thin to intermediate (approximately 2 mean free paths) optical thickness. ILC was not pursued in 3D due to its anticipated excessive computational cost. DD was unreliable (as expected) over the range of test problems. We conclude that IEC and EC are apt methods for a wide range of problems, and provide the ability to perform realistic engineering calculations on coarse cells given nonnegative group-to-group, ordinate-to-ordinate cross section data.
NASA Astrophysics Data System (ADS)
Cai, Jian; Roy, Somesh; Modest, Michael F.
2016-10-01
In simulations of periodic or symmetric geometries, computational domains are reduced by imaginary boundaries that exploit the symmetry conditions. Two boundary conditions are proposed for Discrete Ordinate Methods to solve axisymmetric radiation problems. Firstly, a specularly reflective boundary condition similar to that is used in Photon Monte Carlo methods is developed for Discrete Ordinate Methods. Secondly, the rotational invariant formulation is revisited for axisymmetric wedge geometries. Correspondingly, a new rotationally invariant boundary condition specially designed for axisymmetric problems on wedge shape is proposed to enforce the rotational invariance properties possessed by the radiative transfer equation (RTE) but violated by three-dimensional conventional Discrete Ordinate Methods. Both boundary conditions have the advantage that the discretization and linear equation solution procedures of conventional three-dimensional DOM are not affected by changing to a reduced geometry. Consistency, accuracy and efficiency of the new boundary conditions are demonstrated by multiple numerical examples involving periodic symmetry and axisymmetry. A comparison between specularly reflective boundary conditions and the rotationally invariant formulation shows that the latter offers several advantages for wedge geometries. In other symmetry conditions, when the rotational invariant formulation is not applicable, specular reflective boundary conditions are still effective.
The TORT three-dimensional discrete ordinates neutron/photon transport code (TORT version 3)
Rhoades, W.A.; Simpson, D.B.
1997-10-01
TORT calculates the flux or fluence of neutrons and/or photons throughout three-dimensional systems due to particles incident upon the system`s external boundaries, due to fixed internal sources, or due to sources generated by interaction with the system materials. The transport process is represented by the Boltzman transport equation. The method of discrete ordinates is used to treat the directional variable, and a multigroup formulation treats the energy dependence. Anisotropic scattering is treated using a Legendre expansion. Various methods are used to treat spatial dependence, including nodal and characteristic procedures that have been especially adapted to resist numerical distortion. A method of body overlay assists in material zone specification, or the specification can be generated by an external code supplied by the user. Several special features are designed to concentrate machine resources where they are most needed. The directional quadrature and Legendre expansion can vary with energy group. A discontinuous mesh capability has been shown to reduce the size of large problems by a factor of roughly three in some cases. The emphasis in this code is a robust, adaptable application of time-tested methods, together with a few well-tested extensions.
Monte Carlo and discrete-ordinate simulations of irradiances in the coupled atmosphere-ocean system.
Gjerstad, Karl Idar; Stamnes, Jakob J; Hamre, Børge; Lotsberg, Jon K; Yan, Banghua; Stamnes, Knut
2003-05-20
We compare Monte Carlo (MC) and discrete-ordinate radiative-transfer (DISORT) simulations of irradiances in a one-dimensional coupled atmosphere-ocean (CAO) system consisting of horizontal plane-parallel layers. The two models have precisely the same physical basis, including coupling between the atmosphere and the ocean, and we use precisely the same atmospheric and oceanic input parameters for both codes. For a plane atmosphere-ocean interface we find agreement between irradiances obtained with the two codes to within 1%, both in the atmosphere and the ocean. Our tests cover case 1 water, scattering by density fluctuations both in the atmosphere and in the ocean, and scattering by particulate matter represented by a one-parameter Henyey-Greenstein (HG) scattering phase function. The CAO-MC code has an advantage over the CAO-DISORT code in that it can handle surface waves on the atmosphere-ocean interface, but the CAO-DISORT code is computationally much faster. Therefore we use CAO-MC simulations to study the influence of ocean surface waves and propose a way to correct the results of the CAO-DISORT code so as to obtain fast and accurate underwater irradiances in the presence of surface waves.
Selcuk, N.; Kayakol, N.
1996-11-01
Effects of order of approximation (S{sub 2} and S{sub 4}), angular quadrature (S{sub n} and S{sub n}{prime}) and spatial differencing (diamond and variable-weight) schemes, on the predictive accuracy of discrete ordinates method were investigated by predicting the distributions of radiative flux density and source term of a rectangular enclosure problem and comparing the results with exact solutions produced previously. The enclosure problem is based on data reported earlier on a large-scale experimental furnace with steep temperature gradients. It is a black-walled enclosure containing an absorbing-emitting medium of constant properties. Comparisons show that better agreement is obtained in radiative energy source terms than in flux densities and that the order of approximation plays a more significant role than angular quadrature and spatial differencing schemes in the accuracy of predicted radiative flux densities and radiative energy source terms. Only slight improvements are obtained when S{sub n} and variable-weight differencing schemes are employed.
Polarized multi-dimensional radiative transfer using the discrete ordinates method
Haferman, J.L.; Smith, T.F.; Krajewski, W.F.
1996-11-01
A polarized multi-dimensional radiative transfer model based on the discrete-ordinates method is developed. The model solves the monochromatic vector radiative transfer equation (VRTE) that considers polarization using the four Stokes parameters. For the VRTE, the intensity of the scalar radiative transfer equation is replaced by the Stokes intensity vector; the position-dependent scalar extinction coefficient is replaced by a direction- and position-dependent 4 x 4 extinction matrix; the position-dependent scalar absorption coefficient is replaced by a direction- and position-dependent emission vector; and the scalar phase function is replaced by a scattering phase matrix. The model is capable of solving the VRTE in anisotropically scattering one-, two-, or three-dimensional Cartesian geometries. The model is validated for one-dimensional polarized radiative transfer by comparing its results to several benchmark cases available in the literature. The model results are accurate so long as a quadrature set is chosen so that all phase functions used for a given problem normalize to unity. The model has been developed using a parallel computing paradigm, where each Stokes parameter is solved for on a separate computer processing unit.
Mathews, K.; Sjoden, G.; Minor, B. )
1994-09-01
The exponential characteristic spatial quadrature for discrete ordinates neutral particle transport in slab geometry is derived and compared with current methods. It is similar to the linear characteristic (or, in slab geometry, the linear nodal) quadrature but differs by assuming an exponential distribution of the scattering source within each cell, S(x) = a exp(bx), whose parameters are root-solved to match the known (from the previous iteration) average and first moment of the source over the cell. Like the linear adaptive method, the exponential characteristic method is positive and nonlinear but more accurate and more readily extended to other cell shapes. The nonlinearity has not interfered with convergence. The authors introduce the exponential moment functions,'' a generalization of the functions used by Walters in the linear nodal method, and use them to avoid numerical ill-conditioning. The method exhibits O([Delta]x[sup 4]) truncation error on fine enough meshes; the error is insensitive to mesh size for coarse meshes. In a shielding problem, it is accurate to 10% using 16-mfp-thick cells; conventional methods err by 8 to 15 orders of magnitude. The exponential characteristic method is computationally more costly per cell than current methods but can be accurate with very thick cells, leading to increased computational efficiency on appropriate problems.
NASA Astrophysics Data System (ADS)
Walters, William J.; Haghighat, Alireza
2014-06-01
A new collision source method has been developed to solve the Linear Boltzmann Equation (LBE) more efficiently by adaptation of the angular quadrature order. The angular adaptation method is unique in that the flux from each scattering source iteration is obtained separately, with potentially a different quadrature order. This allows for an optimal use of processing power, by using a high order quadrature for the first few iterations that need it, before shifting to lower order quadratures for the remaining iterations. This is essentially an extension of the first collision source method, and we call it the adaptive collision source method (ACS). The ACS methodolog y has been implemented in the TITAN discrete ordinates code, and has shown a speedup of 2-3 on a test problem, with very little loss of accuracy (within a provided adaptive tolerance). Further, the code has been extended to work in parallel environments by angular decomposition. Although the method requires increased parallel communication, tests have shown excellent scalability, with parallel fractions of up to 99%.
NASA Astrophysics Data System (ADS)
Dembele, S.; Lima, K. L. M.; Wen, J. X.
2011-11-01
For radiative transfer in complex geometries, Sakami and his co-workers have developed a discrete ordinates method (DOM) exponential scheme for unstructured meshes which was mainly applied to gray media. The present study investigates the application of the unstructured exponential scheme to a wider range of non-gray scenarios found in fire and combustion applications, with the goal to implement it in an in-house Computational Fluid Dynamics (CFD) code for fire simulations. The original unstructured gray exponential scheme is adapted to non-gray applications by employing a statistical narrow-band/correlated-k (SNB-CK) gas model and meshes generated using the authors' own mesh generator. Different non-gray scenarios involving spectral gas absorption by H2O and CO2 are investigated and a comparative analysis is carried out between heat flux and radiative source terms predicted and literature data based on ray-tracing and Monte Carlo methods. The maximum discrepancies for total radiative heat flux do not typically exceed 5%.
Sakami, M.; Charette, A.
1999-07-01
Radiative transfer is the dominant mode of heat transfer in many applications. Examples of such applications include combustion chambers, space, greenhouses, rocket plume sensing, to name only a few. However, due to the difficulty in finding an exact analytical solution to the integro-differential radiative transfer equation (RTE) in general absorbing-emitting-scattering media, a diversity of numerical methods have been worked out over the last forty years. In this work, an extension of a modified discrete ordinates method recently proposed by other researchers is presented. It is intended to counter the ray effect inherent in this method. The media analyzed are absorbing, emitting and isotropically or anisotropically scattering and the enclosure geometry is arbitrary. Cases where obstructions are present are also treated. The radiative intensity is broken into two parts: the wall-related intensity and the medium-related intensity. The former is treated separately by rigorous integration over the entire solid boundary. The new differencing scheme recently developed by the authors and based on triangular grids is used for the treatment of the medium-related intensity. Results confirm that the proposed method is a good general remedy for anomalies caused by the ray effect due to the geometry.
Development of the Adaptive Collision Source (ACS) method for discrete ordinates
Walters, W.; Haghighat, A.
2013-07-01
We have developed a new collision source method to solve the Linear Boltzmann Equation (LBE) more efficiently by adaptation of the angular quadrature order. The angular adaptation method is unique in that the flux from each scattering source iteration is obtained, with potentially a different quadrature order. Traditionally, the flux from every iteration is combined, with the same quadrature applied to the combined flux. Since the scattering process tends to distribute the radiation more evenly over angles (i.e., make it more isotropic), the quadrature requirements generally decrease with each iteration. This allows for an optimal use of processing power, by using a high order quadrature for the first few iterations that need it, before shifting to lower order quadratures for the remaining iterations. This is essentially an extension of the first collision source method, and we call it the adaptive collision source method (ACS). The ACS methodology has been implemented in the TITAN discrete ordinates code, and has shown a relative speedup of 1.5-2.5 on a test problem, for the same desired level of accuracy. (authors)
Ho, C K
2009-01-01
Simulations of UV disinfection systems require accurate models of UV radiation within the reactor. Processes such as reflection and refraction at surfaces within the reactor can impact the intensity of the simulated radiation field, which in turn impacts the simulated dose and performance of the UV reactor. This paper describes a detailed discrete ordinates radiation model and comparisons to a test that recorded the UV radiation distribution around a low pressure UV lamp in a water-filled chamber with a UV transmittance of 88%. The effects of reflection and refraction at the quartz sleeve were investigated, along with the impact of wall reflection from the interior surfaces of the chamber. Results showed that the inclusion of wall reflection improved matches between predicted and measured values of incident radiation throughout the chamber. The difference between simulations with and without reflection ranged from several percent near the lamp to nearly 40% further away from the lamp. Neglecting reflection and refraction at the quartz sleeve increased the simulated radiation near the lamp and reduced the simulated radiation further away from the lamp. However, the distribution and trends in the simulated radiation field both with and without the effects of reflection and refraction at the quartz sleeve were consistent with the measured data distributions.
Ho, C K
2009-01-01
Simulations of UV disinfection systems require accurate models of UV radiation within the reactor. Processes such as reflection and refraction at surfaces within the reactor can impact the intensity of the simulated radiation field, which in turn impacts the simulated dose and performance of the UV reactor. This paper describes a detailed discrete ordinates radiation model and comparisons to a test that recorded the UV radiation distribution around a low pressure UV lamp in a water-filled chamber with a UV transmittance of 88%. The effects of reflection and refraction at the quartz sleeve were investigated, along with the impact of wall reflection from the interior surfaces of the chamber. Results showed that the inclusion of wall reflection improved matches between predicted and measured values of incident radiation throughout the chamber. The difference between simulations with and without reflection ranged from several percent near the lamp to nearly 40% further away from the lamp. Neglecting reflection and refraction at the quartz sleeve increased the simulated radiation near the lamp and reduced the simulated radiation further away from the lamp. However, the distribution and trends in the simulated radiation field both with and without the effects of reflection and refraction at the quartz sleeve were consistent with the measured data distributions. PMID:19542648
NASA Astrophysics Data System (ADS)
Huang, Juan-Chen; Hsieh, Tse-Yang; Yang, Jaw-Yen
2015-06-01
A robust and efficient numerical method in phase space combining the conservative discrete ordinate method and high order spatial discretization is proposed for the semiclassical Boltzmann equation with Bhatnagar-Gross-Krook (BGK) relaxation time approximation. A general Maxwell type partially diffuse and partially specular reflection solid wall boundary condition for modeling the gas-surface interactions for semiclassical rarefied gas flows is devised. The discrete ordinate method is first applied to discretize the velocity space of the distribution function to render a set of scalar conservation laws with source term. The high order weighted essentially non-oscillatory scheme is then implemented to evolve the solution in physical space and time. The conservation property of the BGK collision integral is ensured to be fulfilled at the discrete quadrature level approximation. Both specular and diffuse reflection boundary conditions are implemented. Extensive computations of one- and two-dimensional semiclassical rarefied gas dynamical flows covering wide range of flow regimes for three statistics are presented to illustrate the method and boundary conditions treatment. The effect of accommodation coefficient on the rarefied flow field is also examined.
Shedlock, Daniel; Haghighat, Alireza
2005-01-01
In the United States, the Nuclear Waste Policy Act of 1982 mandated centralised storage of spent nuclear fuel by 1988. However, the Yucca Mountain project is currently scheduled to start accepting spent nuclear fuel in 2010. Since many nuclear power plants were only designed for -10 y of spent fuel pool storage, > 35 plants have been forced into alternate means of spent fuel storage. In order to continue operation and make room in spent fuel pools, nuclear generators are turning towards independent spent fuel storage installations (ISFSIs). Typical vertical concrete ISFSIs are -6.1 m high and 3.3 m in diameter. The inherently large system, and the presence of thick concrete shields result in difficulties for both Monte Carlo (MC) and discrete ordinates (SN) calculations. MC calculations require significant variance reduction and multiple runs to obtain a detailed dose distribution. SN models need a large number of spatial meshes to accurately model the geometry and high quadrature orders to reduce ray effects, therefore, requiring significant amounts of computer memory and time. The use of various differencing schemes is needed to account for radial heterogeneity in material cross sections and densities. Two P3, S12, discrete ordinate, PENTRAN (parallel environment neutral-particle TRANsport) models were analysed and different MC models compared. A multigroup MCNP model was developed for direct comparison to the SN models. The biased A3MCNP (automated adjoint accelerated MCNP) and unbiased (MCNP) continuous energy MC models were developed to assess the adequacy of the CASK multigroup (22 neutron, 18 gamma) cross sections. The PENTRAN SN results are in close agreement (5%) with the multigroup MC results; however, they differ by -20-30% from the continuous-energy MC predictions. This large difference can be attributed to the expected difference between multigroup and continuous energy cross sections, and the fact that the CASK library is based on the old ENDF
Shedlock, Daniel; Haghighat, Alireza
2005-01-01
In the United States, the Nuclear Waste Policy Act of 1982 mandated centralised storage of spent nuclear fuel by 1988. However, the Yucca Mountain project is currently scheduled to start accepting spent nuclear fuel in 2010. Since many nuclear power plants were only designed for -10 y of spent fuel pool storage, > 35 plants have been forced into alternate means of spent fuel storage. In order to continue operation and make room in spent fuel pools, nuclear generators are turning towards independent spent fuel storage installations (ISFSIs). Typical vertical concrete ISFSIs are -6.1 m high and 3.3 m in diameter. The inherently large system, and the presence of thick concrete shields result in difficulties for both Monte Carlo (MC) and discrete ordinates (SN) calculations. MC calculations require significant variance reduction and multiple runs to obtain a detailed dose distribution. SN models need a large number of spatial meshes to accurately model the geometry and high quadrature orders to reduce ray effects, therefore, requiring significant amounts of computer memory and time. The use of various differencing schemes is needed to account for radial heterogeneity in material cross sections and densities. Two P3, S12, discrete ordinate, PENTRAN (parallel environment neutral-particle TRANsport) models were analysed and different MC models compared. A multigroup MCNP model was developed for direct comparison to the SN models. The biased A3MCNP (automated adjoint accelerated MCNP) and unbiased (MCNP) continuous energy MC models were developed to assess the adequacy of the CASK multigroup (22 neutron, 18 gamma) cross sections. The PENTRAN SN results are in close agreement (5%) with the multigroup MC results; however, they differ by -20-30% from the continuous-energy MC predictions. This large difference can be attributed to the expected difference between multigroup and continuous energy cross sections, and the fact that the CASK library is based on the old ENDF
Exponential Monte Carlo convergence of a three-dimensional discrete ordinates solution
Favorite, J.A.; Lichtenstein, H.
1999-07-01
Recent work on obtaining exponential convergence for three-dimensional solutions to the spatially and angularly continuous monoenergetic transport equation with isotropic scattering using the reduced source method was promising. The method, however, used two separate estimates of the scalar flux, a Legendre expansion (in the spatial variables) and a quadrature of the angular flux. This introduced an inconsistency that may have led to some convergence problems. To remove this inconsistency and provide a fairer test of the combined reduced source/Monte Carlo method, the method was applied to estimate the coefficients of a Legendre expansion of the solution of the discrete ordinates equations. In this case, no supplementary approximations were required. The method was tested on a homogeneous three-dimensional slab of dimensions 1 x 10{sup 6} x 10{sup 6} cm and material parameters {Sigma}{sub t} = 1 and {Sigma}{sub s} = 0.5. The external source of Eq. (2) was S{sub m}(r{sub s}) = S{sub m}(0,y,z) = {mu}{sub m}, {mu}{sub m} {gt} 0. Figure 1 shows the results of the solution of the S{sub 8} equations using a standard quadrature set, 560,000 particles per stage (except the zeroth, in which only 80,000 particles were used), and Legendre expansions of order 10 in each direction with no Legendre product terms in Eq. (5). For this simple problem, Fig. 1 clearly shows exponential convergence of four different residuals and of two estimates of the known source. The difference between two Monte Carlo scalar fluxes (volume midpoint and volume average) and those estimated by THREE-DANT (Ref. 5) using the same S{sub s} quadrature set are shown for verification. For this problem, convergence was achieved after ten adaptive stages in 75.1 min.
Minor, B.; Mathews, K.
1995-07-01
The exponential characteristic (EC) spatial quadrature for discrete ordinates neutral particle transport previously introduced in slab geometry is extended here to x-y geometry with rectangular cells. The method is derived and compared with current methods. It is similar to the linear characteristic (LC) quadrature (a linear-linear moments method) but differs by assuming an exponential distribution of the scattering source within each cell, S(x) = a exp(bx + cy), whose parameters are rootsolved to match the known (from the previous iteration) spatial average and first moments of the source over the cell. Similarly, EC assumes exponential distributions of flux along cell edges through which particles enter the cell, with parameters chosen to match the average and first moments of flux, as passed from the adjacent, upstream cells (or as determined by boundary conditions). Like the linear adaptive (LA) method, EC is positive and nonlinear. It is more accurate than LA and does not require subdivision of cells. The nonlinearity has not interfered with convergence. The exponential moment functions, which were introduced with the slab geometry method, are extended to arbitrary dimensions (numbers of arguments) and used to avoid numerical ill conditioning. As in slab geometry, the method approaches O({Delta}x{sup 4}) global truncation error on fine-enough meshes, while the error is insensitive to mesh size for coarse meshes. Performance of the method is compared with that of the step characteristic, LC, linear nodal, step adaptive, and LA schemes. The EC method is a strong performer with scattering ratios ranging from 0 to 0.9 (the range tested), particularly so for lower scattering ratios. As in slab geometry, EC is computationally more costly per cell than current methods but can be accurate with very thick cells, leading to increased computational efficiency on appropriate problems.
NASA Astrophysics Data System (ADS)
Zhong, Zhaopeng
In the past twenty 20 years considerable progress has been made in developing new methods for solving the multi-dimensional transport problem. However the effort devoted to the resonance self-shielding calculation has lagged, and much less progress has been made in enhancing resonance-shielding techniques for generating problem-dependent multi-group cross sections (XS) for the multi-dimensional transport calculations. In several applications, the error introduced by self-shielding methods exceeds that due to uncertainties in the basic nuclear data, and often they can be the limiting factor on the accuracy of the final results. This work is to improve the accuracy of the resonance self-shielding calculation by developing continuous energy multi-dimensional transport calculations for problem dependent self-shielding calculations. A new method has been developed, it can calculate the continuous-energy neutron fluxes for the whole two-dimensional domain, which can be utilized as weighting function to process the self-shielded multi-group cross sections for reactor analysis and criticality calculations, and during this process, the two-dimensional heterogeneous effect in the resonance self-shielding calculation can be fully included. A new code, GEMINEWTRN (Group and Energy-Pointwise Methodology Implemented in NEWT for Resonance Neutronics) has been developed in the developing version of SCALE [1], it combines the energy pointwise (PW) capability of the CENTRM [2] with the two-dimensional discrete ordinates transport capability of lattice physics code NEWT [14]. Considering the large number of energy points in the resonance region (typically more than 30,000), the computational burden and memory requirement for GEMINEWTRN is tremendously large, some efforts have been performed to improve the computational efficiency, parallel computation has been implemented into GEMINEWTRN, which can save the computation and memory requirement a lot; some energy points reducing
Cramer, S.N.; Slater, C.O.
1990-05-01
A general Monte Carlo-discrete ordinates radiation transport coupling procedure has been created to study effects of the radiation environment in Hiroshima and Nagasaki due to the bombing of these two cities. The forward two-dimensional free-field air-over-ground flux is coupled with an adjoint Monte Carlo calculation. The size, orientation, or translation of the Monte Carlo geometry is unrestricted. The radiation effects calculated are the dose in the interior of a large concrete building in Nagasaki and the activation production of Co-60 and P-32 in Hiroshima. 20 refs., 6 figs., 1 tab.
Cramer, S.N.; Slater, C.O. )
1993-05-01
A general Monte Carlo-discrete ordinates radiation transport coupling procedure has been created to study effects of the radiation environment in Hiroshima and Nagasaki due to the bombing of these two cities. The forward two-dimensional, free-field, air-over-ground flux is coupled with an adjoint Monte Carlo calculation. The size, orientation, or translation of the Monte Carlo geometry is unrestricted. The radiation effects calculated are the dose in the interior of a large concrete building in Nagasaki and the activation production of [sup 60]Co and [sup 32]P in Hiroshima.
NASA Astrophysics Data System (ADS)
Homma, Yuto; Moriwaki, Hiroyuki; Ohki, Shigeo; Ikeda, Kazumi
2014-06-01
This paper deals with verification of three dimensional triangular prismatic discrete ordinates transport calculation code ENSEMBLE-TRIZ by comparison with multi-group Monte Carlo calculation code GMVP in a large fast breeder reactor. The reactor is a 750 MWe electric power sodium cooled reactor. Nuclear characteristics are calculated at beginning of cycle of an initial core and at beginning and end of cycle of equilibrium core. According to the calculations, the differences between the two methodologies are smaller than 0.0002 Δk in the multi-plication factor, relatively about 1% in the control rod reactivity, and 1% in the sodium void reactivity.
Filho, J. F. P.
2013-07-01
In this work, an analytical discrete ordinates method is used to solve a nodal formulation of a neutron transport problem in x, y-geometry. The proposed approach leads to an important reduction in the order of the associated eigenvalue systems, when combined with the classical level symmetric quadrature scheme. Auxiliary equations are proposed, as usually required for nodal methods, to express the unknown fluxes at the boundary introduced as additional unknowns in the integrated equations. Numerical results, for the problem defined by a two-dimensional region with a spatially constant and isotropically emitting source, are presented and compared with those available in the literature. (authors)
An Arbitrary Lagrangian-Eulerian Discretization of MHD on 3D Unstructured Grids
Rieben, R N; White, D A; Wallin, B K; Solberg, J M
2006-06-12
We present an arbitrary Lagrangian-Eulerian (ALE) discretization of the equations of resistive magnetohydrodynamics (MHD) on unstructured hexahedral grids. The method is formulated using an operator-split approach with three distinct phases: electromagnetic diffusion, Lagrangian motion, and Eulerian advection. The resistive magnetic dynamo equation is discretized using a compatible mixed finite element method with a 2nd order accurate implicit time differencing scheme which preserves the divergence-free nature of the magnetic field. At each discrete time step, electromagnetic force and heat terms are calculated and coupled to the hydrodynamic equations to compute the Lagrangian motion of the conducting materials. By virtue of the compatible discretization method used, the invariants of Lagrangian MHD motion are preserved in a discrete sense. When the Lagrangian motion of the mesh causes significant distortion, that distortion is corrected with a relaxation of the mesh, followed by a 2nd order monotonic remap of the electromagnetic state variables. The remap is equivalent to Eulerian advection of the magnetic flux density with a fictitious mesh relaxation velocity. The magnetic advection is performed using a novel variant of constrained transport (CT) that is valid for unstructured hexahedral grids with arbitrary mesh velocities. The advection method maintains the divergence free nature of the magnetic field and is second order accurate in regions where the solution is sufficiently smooth. For regions in which the magnetic field is discontinuous (e.g. MHD shocks) the method is limited using a novel variant of algebraic flux correction (AFC) which is local extremum diminishing (LED) and divergence preserving. Finally, we verify each stage of the discretization via a set of numerical experiments.
NASA Astrophysics Data System (ADS)
Korneev, V. G.
2012-09-01
BPS is a well known an efficient and rather general domain decomposition Dirichlet-Dirichlet type preconditioner, suggested in the famous series of papers Bramble, Pasciak and Schatz (1986-1989). Since then, it has been serving as the origin for the whole family of domain decomposition Dirichlet-Dirichlet type preconditioners-solvers as for h so hp discretizations of elliptic problems. For its original version, designed for h discretizations, the named authors proved the bound O(1 + log2 H/ h) for the relative condition number under some restricting conditions on the domain decomposition and finite element discretization. Here H/ h is the maximal relation of the characteristic size H of a decomposition subdomain to the mesh parameter h of its discretization. It was assumed that subdomains are images of the reference unite cube by trilinear mappings. Later similar bounds related to h discretizations were proved for more general domain decompositions, defined by means of coarse tetrahedral meshes. These results, accompanied by the development of some special tools of analysis aimed at such type of decompositions, were summarized in the book of Toselli and Widlund (2005). This paper is also confined to h discretizations. We further expand the range of admissible domain decompositions for constructing BPS preconditioners, in which decomposition subdomains can be convex polyhedrons, satisfying some conditions of shape regularity. We prove the bound for the relative condition number with the same dependence on H/ h as in the bound given above. Along the way to this result, we simplify the proof of the so called abstract bound for the relative condition number of the domain decomposition preconditioner. In the part, related to the analysis of the interface sub-problem preconditioning, our technical tools are generalization of those used by Bramble, Pasciak and Schatz.
Oder, J.M.
1997-12-01
Several new quadrature sets for use in the discrete ordinates method of solving the Boltzmann neutral particle transport equation are derived. These symmetric quadratures extend the traditional symmetric quadratures by allowing ordinates perpendicular to one or two of the coordinate axes. Comparable accuracy with fewer required ordinates is obtained. Quadratures up to seventh order are presented. The validity and efficiency of the quadratures is then tested and compared with the Sn level symmetric quadratures relative to a Monte Carlo benchmark solution. The criteria for comparison include current through the surface, scalar flux at the surface, volume average scalar flux, and time required for convergence. Appreciable computational cost was saved when used in an unstructured tetrahedral cell code using highly accurate characteristic methods. However, no appreciable savings in computation time was found using the new quadratures compared with traditional Sn methods on a regular Cartesian mesh using the standard diamond difference method. These quadratures are recommended for use in three-dimensional calculations on an unstructured mesh.
NASA Astrophysics Data System (ADS)
Zerr, Robert Joseph
2011-12-01
The integral transport matrix method (ITMM) has been used as the kernel of new parallel solution methods for the discrete ordinates approximation of the within-group neutron transport equation. The ITMM abandons the repetitive mesh sweeps of the traditional source iterations (SI) scheme in favor of constructing stored operators that account for the direct coupling factors among all the cells and between the cells and boundary surfaces. The main goals of this work were to develop the algorithms that construct these operators and employ them in the solution process, determine the most suitable way to parallelize the entire procedure, and evaluate the behavior and performance of the developed methods for increasing number of processes. This project compares the effectiveness of the ITMM with the SI scheme parallelized with the Koch-Baker-Alcouffe (KBA) method. The primary parallel solution method involves a decomposition of the domain into smaller spatial sub-domains, each with their own transport matrices, and coupled together via interface boundary angular fluxes. Each sub-domain has its own set of ITMM operators and represents an independent transport problem. Multiple iterative parallel solution methods have investigated, including parallel block Jacobi (PBJ), parallel red/black Gauss-Seidel (PGS), and parallel GMRES (PGMRES). The fastest observed parallel solution method, PGS, was used in a weak scaling comparison with the PARTISN code. Compared to the state-of-the-art SI-KBA with diffusion synthetic acceleration (DSA), this new method without acceleration/preconditioning is not competitive for any problem parameters considered. The best comparisons occur for problems that are difficult for SI DSA, namely highly scattering and optically thick. SI DSA execution time curves are generally steeper than the PGS ones. However, until further testing is performed it cannot be concluded that SI DSA does not outperform the ITMM with PGS even on several thousand or tens of
Tominaga, Nozomu; Shibata, Sanshiro; Blinnikov, Sergei I. E-mail: sshibata@post.kek.jp
2015-08-15
We develop a time-dependent, multi-group, multi-dimensional relativistic radiative transfer code, which is required to numerically investigate radiation from relativistic fluids that are involved in, e.g., gamma-ray bursts and active galactic nuclei. The code is based on the spherical harmonic discrete ordinate method (SHDOM) which evaluates a source function including anisotropic scattering in spherical harmonics and implicitly solves the static radiative transfer equation with ray tracing in discrete ordinates. We implement treatments of time dependence, multi-frequency bins, Lorentz transformation, and elastic Thomson and inelastic Compton scattering to the publicly available SHDOM code. Our code adopts a mixed-frame approach; the source function is evaluated in the comoving frame, whereas the radiative transfer equation is solved in the laboratory frame. This implementation is validated using various test problems and comparisons with the results from a relativistic Monte Carlo code. These validations confirm that the code correctly calculates the intensity and its evolution in the computational domain. The code enables us to obtain an Eddington tensor that relates the first and third moments of intensity (energy density and radiation pressure) and is frequently used as a closure relation in radiation hydrodynamics calculations.
Incorporating Discrete Irregular Fracture Zone Networks into 3D Paleohydrogeologic Simulations
NASA Astrophysics Data System (ADS)
Normani, S. D.
2015-12-01
Dual continuum computational models which include both porous media and discrete fracture zones are valuable tools in assessing groundwater migration and pathways in fractured rock systems. Fracture generation models can produce stochastic realizations of fracture networks which honor geological structures and fracture propagation behaviors. Surface lineament traces can be propagated to depth based on fracture zone statistics to produce representations of geological structures in rock. The generated discrete, complex and irregular fracture zone networks, represented as a triangulated mesh, are embedded using orthogonal quadrilateral elements within a three-dimensional hexahedral finite element mesh. A detailed coupled density-dependent paleohydrogeologic groundwater analysis of a hypothetical 104 km2 portion of the Canadian Shield has been conducted using the discrete-fracture dual continuum finite element model FRAC3DVS to investigate the characterization of large-scale fracture zone networks on groundwater and tracer movement during a 120,000 year paleoclimate cycle. Permeability reduction due to permafrost was also applied. Time series data for the depth of permafrost, along with ice thickness and lake depth, were provided by the University of Toronto (UofT) Glacial Systems Model. The crystalline rock between fracture zones was assigned properties characteristic of those reported for the Canadian Shield. Total dissolved solids concentrations of 300 g/L are encountered at depth. Surface water features and a Digital Elevation Model (DEM) were used in a GIS framework to define the watershed boundaries at surface water divides and to populate the finite element mesh. This work will illustrate the long-term evolution and stability of the geosphere and groundwater systems to external perturbations caused by glaciation through the use of performance measures such as Mean Life Expectancy and the migration of a unit tracer to depth over a paleoclimate cycle.
NASA Astrophysics Data System (ADS)
Beguet, Florian; Bali, Sarah; Christoff, Nicole; Jorda, Laurent; Viseur, Sophie; Bouley, Sylvain; Manolova, Agata; Mari, Jean-Luc
2016-04-01
Impact craters is a typical feature observed at the surface of most bodies in the solar system: terrestrial planets, their satellites, asteroids and even possibly cometary nuclei exhibit impact craters. Their spatial density yields the estimation of the age of the surface, a key parameter required for subsequent geological studies. With the development of interplanetary missions, a large number of solar system objects have been mapped at a high spatial resolution, emphasizing the need for new automatic methods of crater detection and counting. In this work, we present such a method using a new approach based on the analysis of reconstructed 3D meshes instead of 2D images. The robust extraction of feature areas on surface objects embedded in 3D, like circular shapes, is a challenging problem. Classical approaches generally rely on image processing and template matching on a 2D flat projection of the 3D object (for instance a high-resolution picture). In this paper, we propose a full 3D method that mainly relies on curvature analysis. Mean and Gaussian curvatures are estimated on the surface. They are used to label vertices that belong to concave parts corresponding to specific pits on the surface. Centers are located in the targeted surface regions, corresponding to potential crater features. Then "best fit circles" are extracted, based on the rims of the circular shapes. They consist in closed lines exclusively composed of edges of the initial mesh. This approach has been applied to the detection of craters on the asteroid Vesta. Keywords: geometric modeling, 3D meshes, shape recognition, mesh processing, discrete curvatures, asteroids, crater detection, geology, geomorphology.
Vescovi, D.; Berzi, D.; Richard, P.
2014-05-15
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 average volume fraction and distance between the walls. The results of the numerical simulations are used to derive boundary conditions appropriated in the cases of large and small bumpiness. Those boundary conditions are, then, employed to numerically integrate the differential equations of Extended Kinetic Theory, where the breaking of the molecular chaos assumption at volume fraction larger than 0.49 is taken into account in the expression of the dissipation rate. We show that the Extended Kinetic Theory is in very good agreement with the numerical simulations, even for coefficients of restitution as low as 0.50. When the bumpiness is increased, we observe that some of the flowing particles are stuck in the gaps between the wall spheres. As a consequence, the walls are more dissipative than expected, and the flows resemble simple shear flows, i.e., flows of rather constant volume fraction and granular temperature.
An overset mesh approach for 3D mixed element high-order discretizations
NASA Astrophysics Data System (ADS)
Brazell, Michael J.; Sitaraman, Jayanarayanan; Mavriplis, Dimitri J.
2016-10-01
A parallel high-order Discontinuous Galerkin (DG) method is used to solve the compressible Navier-Stokes equations in an overset mesh framework. The DG solver has many capabilities including: hp-adaption, curved cells, support for hybrid, mixed-element meshes, and moving meshes. Combining these capabilities with overset grids allows the DG solver to be used in problems with bodies in relative motion and in a near-body off-body solver strategy. The overset implementation is constructed to preserve the design accuracy of the baseline DG discretization. Multiple simulations are carried out to validate the accuracy and performance of the overset DG solver. These simulations demonstrate the capability of the high-order DG solver to handle complex geometry and large scale parallel simulations in an overset framework.
Daskalov, George M; Baker, R S; Rogers, D W O; Williamson, J F
2002-02-01
Our purpose in this work is to demonstrate that the efficiency of dose-rate computations in 125I brachytherapy, using multigroup discrete ordinates radiation transport simulations, can be significantly enhanced using broad energy group cross sections without a loss of accuracy. To this end, the DANTSYS multigroup discrete ordinates neutral particle transport code was used to estimate the absorbed dose-rate distributions around an 125I-model 6702 seed in two-dimensional (2-D) cylindrical R-Z geometry for four different problems spanning the geometries found in clinical practice. First, simulations with a high resolution 210 energy groups library were used to analyze the photon flux spectral distribution throughout this set of problems. These distributions were used to design an energy group structure consisting of three broad groups along with suitable weighting functions from which the three-group cross sections were derived. The accuracy of 2-D DANTSYS dose-rate calculations was benchmarked against parallel Monte Carlo simulations. Ray effects were remedied by using the DANTSYS internal first collision source algorithm. It is demonstrated that the 125I primary photon spectrum leads to inappropriate weighting functions. An accuracy of +/-5% is achieved in the four problem geometries considered using geometry-independent three-group libraries derived from either material-specific weighting functions or a single material-independent weighting function. Agreement between Monte Carlo and the three-group DANTSYS calculations, within three standard Monte Carlo deviations, is observed everywhere except for a limited region along the Z axis of rotational symmetry, where ray effects are difficult to mitigate. The three-group DANTSYS calculations are 10-13 times faster than ones with a 210-group cross section library for 125I dosimetry problems. Compared to 2-D EGS4 Monte Carlo calculations, the 3-group DANTSYS simulations are a 100-fold more efficient. Provided that these
The Combined Finite-Discrete Element Method applied to the Study of Rock Fracturing Behavior in 3D
Rougier, Esteban; Bradley, Christopher R.; Broom, Scott T.; Knight, Earl E.; Munjiza, Ante; Sussman, Aviva J.; Swift, Robert P.
2011-01-01
Since its introduction the combined finite-discrete element method (FEM/DEM), has become an excellent tool to address a wide range of problems involving fracturing and fragmentation of solids. Within the context of rock mechanics, the FEM/DEM method has been applied to many complex industrial problems such as block caving, deep mining techniques, rock blasting, seismic waves, packing problems, rock crushing problems, etc. In the real world most of the problems involving fracture and fragmentation of solids are three dimensional problems. With the aim of addressing these problems an improved 2D/3D FEM/DEM capability has been developed at Los Alamos National Laboratory (LANL). These capabilities include state of the art 3D contact detection, contact interaction, constitutive material models, and fracture models. In this paper, Split Hopkinson Pressure Bar (SHPB) Brazilian experiments are simulated using this improved 2D/3D FEM/DEM approach which is implemented in LANL's MUNROU (Munjiza-Rougier) code. The results presented in this work show excellent agreement with both the SHPB experiments and previous 2D numerical simulations performed by other FEM/DEM research groups.
Investigators are frequently confronted with data sets that include both discrete observations and extended time series of environmental data that had been collected by autonomous recorders. Evaluating the relationships between these two kinds of data is challenging. A common a...
Cramer, S.N.; Slater, C.O.
1990-01-01
A general adjoint Monte Carlo-forward discrete ordinates radiation transport calculational scheme has been created to study effects of the radiation environment in Hiroshima and Nagasaki due to the bombing of these two cities. Three principal areas of investigation are: (1) to determine by experiment and calculation the neutron and gamma-ray energy and angular spectra and total yield of the two weapons, (2) using these weapon descriptions as source terms, to compute radiation effects at several locations in the two cities for comparison with experimental data collected at various times after the bombings and thus validate the source terms, and (3) to compute radiation fields at the known locations of fatalities and surviving individuals at the time of the bombings and thus establish an absolute cause-and-effect relationship between the radiation received and the resulting injuries to these individuals and any of their descendants as indicated by their medical records. 5 refs., 2 figs.
Minor, B.M.
1993-09-01
The exponential characteristic spatial quadrature for discrete ordinates neutral particle transport with rectangular cells is developed. Numerical problems arising in the derivation required the development of exponential moment functions. These functions are used to remove indeterminant forms which can cause catastrophic cancellations. The EC method is positive and nonlinear. It conserves particles and satisfies first moment balance. Comparisons of the EC method's performance to other methods in optically thin and thick spatial cells were performed. For optically thin cells, the EC method was shown to converge to the correct answer, with third order truncation error in the thin cell limit. In deep penetration problems, the EC method attained its highest computational efficiencies compared to the other methods. For all the deep penetration problems examined, the number of spatial cells required by the EC method to attain a desired accuracy was less than the other methods.... Mathematics functions, Nuclear radiation, Nuclear engineering, Radiation attenuation, Radiation shielding, Transport theory, Radiation transport.
Pautz, A.
2006-07-01
Additional functionality has been added to the Discrete Ordinates transport code DORT in order to produce few-group, homogenized cross sections for typical fuel assembly geometries, both on the assembly and the pin cell level. It is demonstrated, that even on the pin-by-pin level almost perfect reaction rate and pin power conservation can be achieved by using the so called Super-homogenization (SPH) algorithm. This method also allows the generation of appropriate reflector cross sections, which can significantly improve the quality of pin power values in the vicinity of moderator regions. The effectiveness of this approach is demonstrated on several examples, including single fuel assembly calculations as well as the C5G7-MOX and the recent NBA VENUS-7 plutonium recycling benchmark problems. (authors)
Donner, René; Menze, Bjoern H; Bischof, Horst; Langs, Georg
2013-12-01
The accurate localization of anatomical landmarks is a challenging task, often solved by domain specific approaches. We propose a method for the automatic localization of landmarks in complex, repetitive anatomical structures. The key idea is to combine three steps: (1) a classifier for pre-filtering anatomical landmark positions that (2) are refined through a Hough regression model, together with (3) a parts-based model of the global landmark topology to select the final landmark positions. During training landmarks are annotated in a set of example volumes. A classifier learns local landmark appearance, and Hough regressors are trained to aggregate neighborhood information to a precise landmark coordinate position. A non-parametric geometric model encodes the spatial relationships between the landmarks and derives a topology which connects mutually predictive landmarks. During the global search we classify all voxels in the query volume, and perform regression-based agglomeration of landmark probabilities to highly accurate and specific candidate points at potential landmark locations. We encode the candidates' weights together with the conformity of the connecting edges to the learnt geometric model in a Markov Random Field (MRF). By solving the corresponding discrete optimization problem, the most probable location for each model landmark is found in the query volume. We show that this approach is able to consistently localize the model landmarks despite the complex and repetitive character of the anatomical structures on three challenging data sets (hand radiographs, hand CTs, and whole body CTs), with a median localization error of 0.80 mm, 1.19 mm and 2.71 mm, respectively. PMID:23664450
Donner, René; Menze, Bjoern H.; Bischof, Horst; Langs, Georg
2013-01-01
The accurate localization of anatomical landmarks is a challenging task, often solved by domain specific approaches. We propose a method for the automatic localization of landmarks in complex, repetitive anatomical structures. The key idea is to combine three steps: (1) a classifier for pre-filtering anatomical landmark positions that (2) are refined through a Hough regression model, together with (3) a parts-based model of the global landmark topology to select the final landmark positions. During training landmarks are annotated in a set of example volumes. A classifier learns local landmark appearance, and Hough regressors are trained to aggregate neighborhood information to a precise landmark coordinate position. A non-parametric geometric model encodes the spatial relationships between the landmarks and derives a topology which connects mutually predictive landmarks. During the global search we classify all voxels in the query volume, and perform regression-based agglomeration of landmark probabilities to highly accurate and specific candidate points at potential landmark locations. We encode the candidates’ weights together with the conformity of the connecting edges to the learnt geometric model in a Markov Random Field (MRF). By solving the corresponding discrete optimization problem, the most probable location for each model landmark is found in the query volume. We show that this approach is able to consistently localize the model landmarks despite the complex and repetitive character of the anatomical structures on three challenging data sets (hand radiographs, hand CTs, and whole body CTs), with a median localization error of 0.80 mm, 1.19 mm and 2.71 mm, respectively. PMID:23664450
Daskalov, G M; Baker, R S; Rogers, D W; Williamson, J F
2000-10-01
The DANTSYS multigroup discrete ordinates computer code is applied to quantitatively estimate the absorbed dose rate distributions in the vicinity of a microSelectron 192Ir high-dose-rate (HDR) source in two-dimensional cylindrical R-Z geometry. The source is modeled in a cylindrical water phantom of diameter 20 cm and height 20 cm. The results are also used for evaluation of the Task Group 43 (TG-43) dosimetric quantities. The DANTSYS accuracy is estimated by direct comparisons with corresponding Monte Carlo results. Our 210-group photon cross section library developed previously, together with angular quadratures consisting of 36 (S16) to 210 (S40) directions and associated weights per octant, are used in the DANTSYS simulations. Strong ray effects are observed but are significantly mitigated through the use of DANTSYS's stochastic ray-tracing first collision source algorithm. The DANTSYS simulations closely approximate Monte Carlo estimates of both direct dose calculations and TG-43 dosimetric quantities. The discrepancies with S20 angular quadrature (55 directions and weights per octant) or higher are shown to be less than +/- 5% (about 2.5 standard deviations of Monte Carlo calculations) everywhere except for limited regions along the Z axis of rotational symmetry, where technical limitations in the DANTSYS first collision source implementation makes adequate suppression of ray effects difficult to achieve. The efficiency of DANTSYS simulations is compared with that of the EGS4 Monte Carlo code. It is demonstrated that even with the 210-group cross section library, DANTSYS achieves two-fold efficiency gains using the the S20 quadrature set. The potential of discrete ordinates method for further efficiency improvements is also discussed. PMID:11099199
Advancements in generalized-geometry discrete ordinates transport for lattice physics calculations
DeHart, M. D.
2006-07-01
This paper describes the generalized-geometry capabilities of the two-dimensional NEWT transport solver, used within the TRITON depletion sequence of the SCALE code system for lattice physics calculation. With the release of SCALE 5.1 in 2006, NEWT will introduce a new automated grid generation procedure based on simple body specifications, using an input format based on the SCALE Generalized-Geometry Processor. The paper will contrast the discretization techniques against those used in other unstructured grid treatments; illustrate the ease of model development, features, capabilities; and demonstrate the unique adaptability of NEWT for a wide range of fuel configurations. (authors)
NASA Astrophysics Data System (ADS)
Guo, Liancheng; Morita, Koji; Tagami, Hirotaka; Tobita, Yoshiharu
2014-06-01
The postulated core disruptive accidents (CDAs) are regarded as particular difficulties in the safety analysis of liquid-metal fast reactors (LMFRs). In CDAs, the motions and interactions of solid particles, such as refrozen fuels, disrupted pellets, etc., not only dominate fundamental behaviors of multiphase flows, but also drastically influence the process of CDAs. The fast reactor safety analysis code, SIMMER-IV, which is a 3D, multi-velocity-field, multiphase, multicomponent, Eulerian, fluid dynamics code coupled with a fuel-pin model and a space- and energy-dependent neutron kinetics model, was successfully applied to a series of CDA assessments. However, strong interactions among solid particles as well as particle characteristics in multiphase flows with rich solid particles were not taken into consideration for fluid-dynamics models of SIMMER-IV. In this article, a hybrid method for multiphase flow analysis is developed by coupling the discrete element method (DEM) with the multi-fluid model of SIMMER-IV. In the coupling algorithm, motions of liquid and gas phases are solved by a time-factorization (time-splitting) method. For the solid phases, contacts among particles and interactions with fluid phases are considered through DEM. Numerical simulations of dam-break behavior with rich solid particles show reasonable agreements with corresponding experimental results. It is expected that SIMMER-IV coupled with DEM could provide a promising and useful computational tool for complicated multiphase-flow phenomena with high concentration of solid particles.
Sjoden, G.E.
1992-03-01
A new discrete ordinates spatial quadrature scheme is presented for solving neutral particle transport problems. This new scheme, called the exponential characteristic method, is developed here in slab geometry with isotropic scattering. This method uses a characteristic integration of the Boltzmann transport equation with an exponential function as the assumed from of the source distribution, continuous across each spatial cell. The exponential source function is constructed to globally conserve zeroth and first spatial source moments and is non-negative. Characteristic integration ensures non-negative fluxes and flux moments. Numerical testing indicates that convergence of the exponential characteristic scheme is fourth order in the limit of vanishingly thin cells. Highly accurate solutions to optically thick problems can result using this scheme with very coarse meshes. Comparing accuracy and computational cost with existing spatial quadrature schemes (diamond difference, linear discontinuous, linear characteristic, linear adaptive, etc.), the exponential characteristic scheme typically performed best. This scheme is expected to be expandable to two dimensions in a straight forward manner. Due to the high accuracies achievable using coarse meshes, this scheme may allow researchers to obtain solutions to transport problems once thought too large or too difficult to be adequately solved conventional computer systems.
NASA Astrophysics Data System (ADS)
Trabelsi, H.; Sghaier, T.; Sifaoui, M. S.
2005-07-01
A modified discrete ordinates method (DOM) is used in spherical participating media. The radiative intensity is broken up into two components. One component is traced back to the enclosure's source. It is called direct intensity. The other component is rather traced back to the contribution of the medium itself. It is called diffuse intensity. Thus, the radiative transfer equation (RTE) is transformed into two simultaneous equations: a direct RTE and a diffuse RTE. The direct RTE is solved analytically. The diffuse RTE is solved numerically using the DOM. The streaming angular derivative term appearing in spherical geometry is modeled by making use of the Finite Legendre Transform. We study a pure radiation transfer problem between two concentric spheres. The medium is assumed to be gray and isotropically scattering. The limiting spheres are considered to be opaque, gray, diffusely emitting and diffusely reflecting with uniform emissivity over each surface. The obtained results are compared with available cases reported in the literature. In particular, relative importance of the direct radiation in optically thin media is studied.
Kodeli, Ivo; Tanner, Rick
2005-01-01
In the scope of QUADOS, a Concerted Action of the European Commission, eight calculational problems were prepared in order to evaluate the use of computational codes for dosimetry in radiation protection and medical physics, and to disseminate "good practice" throughout the radiation dosimetry community. This paper focuses on the analysis of the P4 problem on the 'TLD-albedo dosemeter: neutron and/or photon response of a four-element TL-dosemeter mounted on a standard ISO slab phantom'. Altogether 17 solutions were received from the participants, 14 of those transported neutrons and 15 photons. Most participants (16 out of 17) used Monte Carlo methods. These calculations are time-consuming, requiring several days of CPU time to perform the whole set of calculations and achieve good statistical precision. The possibility of using deterministic discrete ordinates codes as an alternative to Monte Carlo was therefore investigated and is presented here. In particular the capacity of the adjoint mode calculations is shown. PMID:16381782
NASA Astrophysics Data System (ADS)
Lu, C.; Tang, C.; Hu, J.; Chan, Y.; Chi, C.
2011-12-01
The subtropical climate and annual average about four typhoons, combined with frequent earthquakes trigger the landslide hazards in mountainous area in Taiwan. The potential Lushan landslide area is located at a famous hotspring district of Nantou County in central Taiwan which slides frequently due to heavy rainfall during pouring rain or typhoon seasons. Lushan landslide demonstrates a typical deep-seated (up to 80 meters) creep deformation of a slate rock slope with high dip angles. Under the weathering effects, the slide surface is currently extending to the lower slope was formed by the coalescing of the joints on the upper eastern slope as well as the interface between the sandy slate and the slate on the upper western slope. In this study, we simulate the process of Lushan landslide by using PFC3D, which is conducted by adopting the 3D granular discrete element method. In this simulation, we assume the whole sliding block as an inhomogeneous layer of weaken slate. We extrapolate the slip plane depth according to the result of borehole, TDR and RIF profiles. The main landslide area is about 18 hectares and the volume is about 9 million cubic meters, which is filled with 30 thousand ball elements. The topography is represented by 25,620 wall elements based on the 5m digital elevation model. We set 9 monitoring balls on surface to monitor the velocity and run-out path. According to the field work, we defined the weak planes by the strike and dip of cleavage and joint. From our results, the run-out zone is about 40 hectares. The debris will cover whole Lushan hotspring district in 20 seconds and all rock mass will almost stop after 150 seconds. The predicted maximum velocity is about 40m/s. According to the velocity profile, we can see three and four times accelerations from monitored particles. The collision of particles during sliding and complex terrain explains the fluctuation of velocity profile with time. The numerical results of this study will provide
2014-01-01
Locomotion over deformable substrates is a common occurrence in nature. Footprints represent sedimentary distortions that provide anatomical, functional, and behavioral insights into trackmaker biology. The interpretation of such evidence can be challenging, however, particularly for fossil tracks recovered at bedding planes below the originally exposed surface. Even in living animals, the complex dynamics that give rise to footprint morphology are obscured by both foot and sediment opacity, which conceals animal–substrate and substrate–substrate interactions. We used X-ray reconstruction of moving morphology (XROMM) to image and animate the hind limb skeleton of a chicken-like bird traversing a dry, granular material. Foot movement differed significantly from walking on solid ground; the longest toe penetrated to a depth of ∼5 cm, reaching an angle of 30° below horizontal before slipping backward on withdrawal. The 3D kinematic data were integrated into a validated substrate simulation using the discrete element method (DEM) to create a quantitative model of limb-induced substrate deformation. Simulation revealed that despite sediment collapse yielding poor quality tracks at the air–substrate interface, subsurface displacements maintain a high level of organization owing to grain–grain support. Splitting the substrate volume along “virtual bedding planes” exposed prints that more closely resembled the foot and could easily be mistaken for shallow tracks. DEM data elucidate how highly localized deformations associated with foot entry and exit generate specific features in the final tracks, a temporal sequence that we term “track ontogeny.” This combination of methodologies fosters a synthesis between the surface/layer-based perspective prevalent in paleontology and the particle/volume-based perspective essential for a mechanistic understanding of sediment redistribution during track formation. PMID:25489092
Falkingham, Peter L; Gatesy, Stephen M
2014-12-23
Locomotion over deformable substrates is a common occurrence in nature. Footprints represent sedimentary distortions that provide anatomical, functional, and behavioral insights into trackmaker biology. The interpretation of such evidence can be challenging, however, particularly for fossil tracks recovered at bedding planes below the originally exposed surface. Even in living animals, the complex dynamics that give rise to footprint morphology are obscured by both foot and sediment opacity, which conceals animal-substrate and substrate-substrate interactions. We used X-ray reconstruction of moving morphology (XROMM) to image and animate the hind limb skeleton of a chicken-like bird traversing a dry, granular material. Foot movement differed significantly from walking on solid ground; the longest toe penetrated to a depth of ∼5 cm, reaching an angle of 30° below horizontal before slipping backward on withdrawal. The 3D kinematic data were integrated into a validated substrate simulation using the discrete element method (DEM) to create a quantitative model of limb-induced substrate deformation. Simulation revealed that despite sediment collapse yielding poor quality tracks at the air-substrate interface, subsurface displacements maintain a high level of organization owing to grain-grain support. Splitting the substrate volume along "virtual bedding planes" exposed prints that more closely resembled the foot and could easily be mistaken for shallow tracks. DEM data elucidate how highly localized deformations associated with foot entry and exit generate specific features in the final tracks, a temporal sequence that we term "track ontogeny." This combination of methodologies fosters a synthesis between the surface/layer-based perspective prevalent in paleontology and the particle/volume-based perspective essential for a mechanistic understanding of sediment redistribution during track formation.
Sørensen, V; Ingvaldsen, R P; Whiting, H T
2001-07-01
The purpose of this experiment was to explore the application of co-ordination dynamics to the analysis of discrete rather than cyclical movements. Subjects, standing in a fixed position, were required to return table-tennis balls delivered to different spatial locations in the direction of a fixed target. This was achieved in condition 1 by systematically scaling, from left to right and vice versa, the 'spatial location' of the ball-identified as a control parameter. In condition 2, the control condition, the spatial location was varied randomly over the same range. The changes between regimes of the stroke co-ordination pattern, defined at two different levels, (1) organisational--forehand or backhand drive. and (2) kinematic-the distance of the bat at ball-bat contact relative to the leading edge of the table, were identified as collective variables, the values of which changed spontaneously at the transition points exposed by the control parameter. The switch between regimes was shown to be dependent upon the direction of scaling, i.e. a hysteresis effect was identified in both conditions. These findings confirm that the conceptual and methodological frameworks of co-ordination dynamics can be applied, appropriately, to the analysis of discrete movements. Moreover, it would seem that control parameter values (spatial location of the ball) do not necessarily have to be scaled in a systematic way in order to produce the required effects. PMID:11471838
3-D transient analysis of pebble-bed HTGR by TORT-TD/ATTICA3D
Seubert, A.; Sureda, A.; Lapins, J.; Buck, M.; Bader, J.; Laurien, E.
2012-07-01
As most of the acceptance criteria are local core parameters, application of transient 3-D fine mesh neutron transport and thermal hydraulics coupled codes is mandatory for best estimate evaluations of safety margins. This also applies to high-temperature gas cooled reactors (HTGR). Application of 3-D fine-mesh transient transport codes using few energy groups coupled with 3-D thermal hydraulics codes becomes feasible in view of increasing computing power. This paper describes the discrete ordinates based coupled code system TORT-TD/ATTICA3D that has recently been extended by a fine-mesh diffusion solver. Based on transient analyses for the PBMR-400 design, the transport/diffusion capabilities are demonstrated and 3-D local flux and power redistribution effects during a partial control rod withdrawal are shown. (authors)
SB3D User Manual, Santa Barbara 3D Radiative Transfer Model
O'Hirok, William
1999-01-01
SB3D is a three-dimensional atmospheric and oceanic radiative transfer model for the Solar spectrum. The microphysics employed in the model are the same as used in the model SBDART. It is assumed that the user of SB3D is familiar with SBDART and IDL. SB3D differs from SBDART in that computations are conducted on media in three-dimensions rather than a single column (i.e. plane-parallel), and a stochastic method (Monte Carlo) is employed instead of a numerical approach (Discrete Ordinates) for estimating a solution to the radiative transfer equation. Because of these two differences between SB3D and SBDART, the input and running of SB3D is more unwieldy and requires compromises between model performance and computational expense. Hence, there is no one correct method for running the model and the user must develop a sense to the proper input and configuration of the model.
da Silva, Anabela; Elias, Mady; Andraud, Christine; Lafait, Jacques
2003-12-01
Two methods for solving the radiative transfer equation are compared with the aim of computing the angular distribution of the light scattered by a heterogeneous scattering medium composed of a single flat layer or a multilayer. The first method [auxiliary function method (AFM)], recently developed, uses an auxiliary function and leads to an exact solution; the second [discrete-ordinate method (DOM)] is based on the channel concept and needs an angular discretization. The comparison is applied to two different media presenting two typical and extreme scattering behaviors: Rayleigh and Mie scattering with smooth or very anisotropic phase functions, respectively. A very good agreement between the predictions of the two methods is observed in both cases. The larger the number of channels used in the DOM, the better the agreement. The principal advantages and limitations of each method are also listed.
NASA Astrophysics Data System (ADS)
Tominaga, Nozomu; Shibata, Sanshiro; Blinnikov, Sergei I.
2015-08-01
We develop a time-dependent, multi-group, multi-dimensional relativistic radiative transfer code, which is required to numerically investigate radiation from relativistic fluids that are involved in, e.g., gamma-ray bursts and active galactic nuclei. The code is based on the spherical harmonic discrete ordinate method (SHDOM) which evaluates a source function including anisotropic scattering in spherical harmonics and implicitly solves the static radiative transfer equation with ray tracing in discrete ordinates. We implement treatments of time dependence, multi-frequency bins, Lorentz transformation, and elastic Thomson and inelastic Compton scattering to the publicly available SHDOM code. Our code adopts a mixed-frame approach; the source function is evaluated in the comoving frame, whereas the radiative transfer equation is solved in the laboratory frame. This implementation is validated using various test problems and comparisons with the results from a relativistic Monte Carlo code. These validations confirm that the code correctly calculates the intensity and its evolution in the computational domain. The code enables us to obtain an Eddington tensor that relates the first and third moments of intensity (energy density and radiation pressure) and is frequently used as a closure relation in radiation hydrodynamics calculations.
Self-assembly of the first discrete 3d-4f-4f triple-stranded helicate.
Riis-Johannessen, Thomas; Bernardinelli, Gérald; Filinchuk, Yaroslav; Clifford, Sarah; Dalla Favera, Natalia; Piguet, Claude
2009-06-15
The connection of an additional bidentate chelating unit at the extremity of a segmental bis-tridentate ligand in L5 provides an unprecedented sequence of binding sites for the self-assembly of heterometallic 3d-4f triple-stranded helicates. Thorough thermodynamic and structural investigations in acetonitrile show the formation of intricate mixtures of complexes when a single type of metal (3d or 4f) is reacted with L5. However, the situation is greatly simplified when Zn(II) (3d-block) and Lu(III) (4f-block) are simultaneously coordinated to L5, thus leading to only two identified species: the target C(3)-symmetrical trinuclear triple-stranded d-f-f helicate HHH-[ZnLu(2)(L5)(3)](8+) and a tetranuclear double-stranded complex [Zn(2)Lu(2)(L5)(2)](10+). Interestingly, the removal of Zn(II) from the former triple-helical complex has only a minor effect on the coordination of Lu(III), and translational autodiffusion coefficients show a simple reduction of the length of the molecular rigid cylinder from L = 2.7 nm in HHH-[ZnLu(2)(L5)(3)](8+) to L = 2.3 nm in HHH-[Lu(2)(L5)(3)](6+). Finally, the complete thermodynamic picture provides five novel stability macroconstants containing information about short-range (ca. 9 A) and long-range (ca. 18 A) intramolecular intermetallic d-f and f-f interactions. PMID:19499959
A 4-point in-situ method to locate a discrete gamma-ray source in 3-D space.
Byun, Jong-In; Choi, Hee-Yeoul; Yun, Ju-Yong
2010-02-01
The determination of the source position (x,y,z) of a discrete gamma-ray source using peak count rates from four measurement points was studied. We derived semi-empirical formulas to find the position under the condition to neglect attenuation effects by obstacles between the target source and the detector. To validate the methodology, we performed the locating experiments for a (137)Cs small volume source placed at 10 different positions on the floor of a laboratory using the formulas derived in this study. In this study, a portable HPGe gamma spectrometry system with a virtual point detector concept was used. The calculation results for the source positions were compared with reference values measured with a rule. The applicability of the methodology was estimated based on the differences of the results. PMID:19932029
Makedonska, Nataliia; Painter, Scott L.; Bui, Quan M.; Gable, Carl W.; Karra, Satish
2015-09-16
The discrete fracture network (DFN) model is a method to mimic discrete pathways for fluid flow through a fractured low-permeable rock mass, and may be combined with particle tracking simulations to address solute transport. However, experience has shown that it is challenging to obtain accurate transport results in three-dimensional DFNs because of the high computational burden and difficulty in constructing a high-quality unstructured computational mesh on simulated fractures. We present a new particle tracking capability, which is adapted to control volume (Voronoi polygons) flow solutions on unstructured grids (Delaunay triangulations) on three-dimensional DFNs. The locally mass-conserving finite-volume approach eliminates mass balance-related problems during particle tracking. The scalar fluxes calculated for each control volume face by the flow solver are used to reconstruct a Darcy velocity at each control volume centroid. The groundwater velocities can then be continuously interpolated to any point in the domain of interest. The control volumes at fracture intersections are split into four pieces, and the velocity is reconstructed independently on each piece, which results in multiple groundwater velocities at the intersection, one for each fracture on each side of the intersection line. This technique enables detailed particle transport representation through a complex DFN structure. Verified for small DFNs, the new simulation capability enables numerical experiments on advective transport in large DFNs to be performed. As a result, we demonstrate this particle transport approach on a DFN model using parameters similar to those of crystalline rock at a proposed geologic repository for spent nuclear fuel in Forsmark, Sweden.
Makedonska, Nataliia; Painter, Scott L.; Bui, Quan M.; Gable, Carl W.; Karra, Satish
2015-09-16
The discrete fracture network (DFN) model is a method to mimic discrete pathways for fluid flow through a fractured low-permeable rock mass, and may be combined with particle tracking simulations to address solute transport. However, experience has shown that it is challenging to obtain accurate transport results in three-dimensional DFNs because of the high computational burden and difficulty in constructing a high-quality unstructured computational mesh on simulated fractures. We present a new particle tracking capability, which is adapted to control volume (Voronoi polygons) flow solutions on unstructured grids (Delaunay triangulations) on three-dimensional DFNs. The locally mass-conserving finite-volume approach eliminates massmore » balance-related problems during particle tracking. The scalar fluxes calculated for each control volume face by the flow solver are used to reconstruct a Darcy velocity at each control volume centroid. The groundwater velocities can then be continuously interpolated to any point in the domain of interest. The control volumes at fracture intersections are split into four pieces, and the velocity is reconstructed independently on each piece, which results in multiple groundwater velocities at the intersection, one for each fracture on each side of the intersection line. This technique enables detailed particle transport representation through a complex DFN structure. Verified for small DFNs, the new simulation capability enables numerical experiments on advective transport in large DFNs to be performed. As a result, we demonstrate this particle transport approach on a DFN model using parameters similar to those of crystalline rock at a proposed geologic repository for spent nuclear fuel in Forsmark, Sweden.« less
Boyce, Christopher M; Holland, Daniel J; Scott, Stuart A; Dennis, John S
2013-12-18
Discrete element modeling is being used increasingly to simulate flow in fluidized beds. These models require complex measurement techniques to provide validation for the approximations inherent in the model. This paper introduces the idea of modeling the experiment to ensure that the validation is accurate. Specifically, a 3D, cylindrical gas-fluidized bed was simulated using a discrete element model (DEM) for particle motion coupled with computational fluid dynamics (CFD) to describe the flow of gas. The results for time-averaged, axial velocity during bubbling fluidization were compared with those from magnetic resonance (MR) experiments made on the bed. The DEM-CFD data were postprocessed with various methods to produce time-averaged velocity maps for comparison with the MR results, including a method which closely matched the pulse sequence and data processing procedure used in the MR experiments. The DEM-CFD results processed with the MR-type time-averaging closely matched experimental MR results, validating the DEM-CFD model. Analysis of different averaging procedures confirmed that MR time-averages of dynamic systems correspond to particle-weighted averaging, rather than frame-weighted averaging, and also demonstrated that the use of Gaussian slices in MR imaging of dynamic systems is valid. PMID:24478537
2013-01-01
Discrete element modeling is being used increasingly to simulate flow in fluidized beds. These models require complex measurement techniques to provide validation for the approximations inherent in the model. This paper introduces the idea of modeling the experiment to ensure that the validation is accurate. Specifically, a 3D, cylindrical gas-fluidized bed was simulated using a discrete element model (DEM) for particle motion coupled with computational fluid dynamics (CFD) to describe the flow of gas. The results for time-averaged, axial velocity during bubbling fluidization were compared with those from magnetic resonance (MR) experiments made on the bed. The DEM-CFD data were postprocessed with various methods to produce time-averaged velocity maps for comparison with the MR results, including a method which closely matched the pulse sequence and data processing procedure used in the MR experiments. The DEM-CFD results processed with the MR-type time-averaging closely matched experimental MR results, validating the DEM-CFD model. Analysis of different averaging procedures confirmed that MR time-averages of dynamic systems correspond to particle-weighted averaging, rather than frame-weighted averaging, and also demonstrated that the use of Gaussian slices in MR imaging of dynamic systems is valid. PMID:24478537
Yifat, Jonathan; Gannot, Israel
2015-03-01
Early detection of malignant tumors plays a crucial role in the survivability chances of the patient. Therefore, new and innovative tumor detection methods are constantly searched for. Tumor-specific magnetic-core nano-particles can be used with an alternating magnetic field to detect and treat tumors by hyperthermia. For the analysis of the method effectiveness, the bio-heat transfer between the nanoparticles and the tissue must be carefully studied. Heat diffusion in biological tissue is usually analyzed using the Pennes Bio-Heat Equation, where blood perfusion plays an important role. Malignant tumors are known to initiate an angiogenesis process, where endothelial cell migration from neighboring vasculature eventually leads to the formation of a thick blood capillary network around them. This process allows the tumor to receive its extensive nutrition demands and evolve into a more progressive and potentially fatal tumor. In order to assess the effect of angiogenesis on the bio-heat transfer problem, we have developed a discrete stochastic 3D model & simulation of tumor-induced angiogenesis. The model elaborates other angiogenesis models by providing high resolution 3D stochastic simulation, capturing of fine angiogenesis morphological features, effects of dynamic sprout thickness functions, and stochastic parent vessel generator. We show that the angiogenesis realizations produced are well suited for numerical bio-heat transfer analysis. Statistical study on the angiogenesis characteristics was derived using Monte Carlo simulations. According to the statistical analysis, we provide analytical expression for the blood perfusion coefficient in the Pennes equation, as a function of several parameters. This updated form of the Pennes equation could be used for numerical and analytical analyses of the proposed detection and treatment method.
Yifat, Jonathan; Gannot, Israel
2015-03-01
Early detection of malignant tumors plays a crucial role in the survivability chances of the patient. Therefore, new and innovative tumor detection methods are constantly searched for. Tumor-specific magnetic-core nano-particles can be used with an alternating magnetic field to detect and treat tumors by hyperthermia. For the analysis of the method effectiveness, the bio-heat transfer between the nanoparticles and the tissue must be carefully studied. Heat diffusion in biological tissue is usually analyzed using the Pennes Bio-Heat Equation, where blood perfusion plays an important role. Malignant tumors are known to initiate an angiogenesis process, where endothelial cell migration from neighboring vasculature eventually leads to the formation of a thick blood capillary network around them. This process allows the tumor to receive its extensive nutrition demands and evolve into a more progressive and potentially fatal tumor. In order to assess the effect of angiogenesis on the bio-heat transfer problem, we have developed a discrete stochastic 3D model & simulation of tumor-induced angiogenesis. The model elaborates other angiogenesis models by providing high resolution 3D stochastic simulation, capturing of fine angiogenesis morphological features, effects of dynamic sprout thickness functions, and stochastic parent vessel generator. We show that the angiogenesis realizations produced are well suited for numerical bio-heat transfer analysis. Statistical study on the angiogenesis characteristics was derived using Monte Carlo simulations. According to the statistical analysis, we provide analytical expression for the blood perfusion coefficient in the Pennes equation, as a function of several parameters. This updated form of the Pennes equation could be used for numerical and analytical analyses of the proposed detection and treatment method. PMID:24462603
Prinja, A.K.
1995-08-01
We have developed and successfully implemented a two-dimensional bilinear discontinuous in space and time, used in conjunction with the S{sub N} angular approximation, to numerically solve the time dependent, one-dimensional, one-speed, slab geometry, (ion) transport equation. Numerical results and comparison with analytical solutions have shown that the bilinear-discontinuous (BLD) scheme is third-order accurate in the space ad time dimensions independently. Comparison of the BLD results with diamond-difference methods indicate that the BLD method is both quantitavely and qualitatively superior to the DD scheme. We note that the form of the transport operator is such that these conclusions carry over to energy dependent problems that include the constant-slowing-down-approximation term, and to multiple space dimensions or combinations thereof. An optimized marching or inversion scheme or a parallel algorithm should be investigated to determine if the increased accuracy can compensate for the extra overhead required for a BLD solution, and then could be compared to other discretization methods such as nodal or characteristic schemes.
NASA Astrophysics Data System (ADS)
Owens, A. R.; Welch, J. A.; Kópházi, J.; Eaton, M. D.
2016-06-01
In this paper two discontinuous Galerkin isogeometric analysis methods are developed and applied to the first-order form of the neutron transport equation with a discrete ordinate (SN) angular discretisation. The discontinuous Galerkin projection approach was taken on both an element level and the patch level for a given Non-Uniform Rational B-Spline (NURBS) patch. This paper describes the detailed dispersion analysis that has been used to analyse the numerical stability of both of these schemes. The convergence of the schemes for both smooth and non-smooth solutions was also investigated using the method of manufactured solutions (MMS) for multidimensional problems and a 1D semi-analytical benchmark whose solution contains a strongly discontinuous first derivative. This paper also investigates the challenges posed by strongly curved boundaries at both the NURBS element and patch level with several algorithms developed to deal with such cases. Finally numerical results are presented both for a simple pincell test problem as well as the C5G7 quarter core MOX/UOX small Light Water Reactor (LWR) benchmark problem. These numerical results produced by the isogeometric analysis (IGA) methods are compared and contrasted against linear and quadratic discontinuous Galerkin finite element (DGFEM) SN based methods.
Slater, C.O.
1990-07-01
Results are reported for two-dimensional discrete ordinates, X-Y geometry calculations performed for seven Halden Heavy Boiling Water Reactor core configurations. The calculations were performed in support of an effort to reassess the neutron fluence received by the reactor vessel. Nickel foil measurement data indicated considerable underprediction of fluences by the previously used multigroup removal- diffusion method. Therefore, calculations by a more accurate method were deemed appropriate. For each core configuration, data are presented for (1) integral fluxes in the core and near the vessel wall, (2) neutron spectra at selected locations, (3) isoflux contours superimposed on the geometry models, (4) plots of the geometry models, and (5) input for the calculations. The initial calculations were performed with several mesh sizes. Comparisons of the results from these calculations indicated that the uncertainty in the calculated fluxes should be less than 10%. However, three-dimensional effects (such as axial asymmetry in the fuel loading) could contribute to much greater uncertainty in the calculated neutron fluxes. 7 refs., 22 figs., 11 tabs.
NASA Technical Reports Server (NTRS)
Tsay, Si-Chee; Stamnes, Knut; Wiscombe, Warren; Laszlo, Istvan; Einaudi, Franco (Technical Monitor)
2000-01-01
This update reports a state-of-the-art discrete ordinate algorithm for monochromatic unpolarized radiative transfer in non-isothermal, vertically inhomogeneous, but horizontally homogeneous media. The physical processes included are Planckian thermal emission, scattering with arbitrary phase function, absorption, and surface bidirectional reflection. The system may be driven by parallel or isotropic diffuse radiation incident at the top boundary, as well as by internal thermal sources and thermal emission from the boundaries. Radiances, fluxes, and mean intensities are returned at user-specified angles and levels. DISORT has enjoyed considerable popularity in the atmospheric science and other communities since its introduction in 1988. Several new DISORT features are described in this update: intensity correction algorithms designed to compensate for the 8-M forward-peak scaling and obtain accurate intensities even in low orders of approximation; a more general surface bidirectional reflection option; and an exponential-linear approximation of the Planck function allowing more accurate solutions in the presence of large temperature gradients. DISORT has been designed to be an exemplar of good scientific software as well as a program of intrinsic utility. An extraordinary effort has been made to make it numerically well-conditioned, error-resistant, and user-friendly, and to take advantage of robust existing software tools. A thorough test suite is provided to verify the program both against published results, and for consistency where there are no published results. This careful attention to software design has been just as important in DISORT's popularity as its powerful algorithmic content.
NASA Astrophysics Data System (ADS)
Tseng, C. H.; Chan, Y. C.; Jeng, C. J.; Hsieh, Y. C.
2015-12-01
Slope failure is a widely observed phenomenon in hill and mountainous areas in Taiwan, which is characterized by high erosion rates (up to 60 mm/yr) due to its climatic and geographical conditions. Slope failure events easily occur after intense rainfall, especially resulting from typhoons and accordingly cause a great loss of human lives and property. At the northern end of the Western Foothill belt in northern Taiwan, Huafan University campus (121.692448˚ E, 24.980724˚ N ) is founded on a dip slope, ~20˚ toward southwest, being composed of early Miocene alternations of sandstone and shale. Data from continuous monitoring over the years by means of inclinometers and groundwater gauges reveal that creep of 6-10 mm of the slope occurred when precipitation exceeded 300 mm during typhoons' striking. In addition, extension cracks on the ground are also found within and on the edge of the campus. Furthermore, potential slip surfaces are detected shown by rock cores to exist 10 and 30 m in depth as well. To understand the kinematic behaviors of the rock slope failure beneath the university campus, a 3D discrete element mothed is applied in this study. Results of the modeling indicate that creeping is the primary behavior pattern when the friction coefficient reduces owing to rise of groundwater during rainstorms. However, rapid slip may take place under influences of earthquake with large magnitude. Suggestions for preventing the slope creep are to construct catchpits to drainage runoff and lower the groundwater table and ground anchors through the slip surfaces to stabilize the slide blocks.
NASA Astrophysics Data System (ADS)
Shi, Ruo-Bing; Pi, Min; Jiang, Shuang-Shuang; Wang, Yuan-Yuan; Jin, Chuan-Ming
2014-08-01
Four new metal-organic frameworks, [Zn(2-mBIM)2(SO3CF3)2·(H2O)4] (1), [Zn(BMIE)(1,4-BDC)]·(H2O)3 (2), [Cd(BIM)2(OH)(H2O)2(PF6)]·(H2O)4 (3), and [Cd(PA-BIM)2 (ClO4)2]·11.33H2O (4) (2-mBIM = bis(2-methylimidazol-1-yl)methane, BMIE = 1,2-bis[1-(2-methylimidazole)-diethoxy]ethane, BIM = bis(imidazol-1-yl)methane, and PA-BIM = 1,1-bis [(2-phenylazo)imidazol-1-yl]methane) have been prepared and structurally characterized. Complex 1 exhibits an infinite 1D cationic beaded-chain structure, which encapsulated discrete octameric water clusters that are comprised of a chair-like hexameric water cluster with two extra water molecules dangling on two diagonal vertices of the chair. Complex 2 forms a 1D infinite zigzag metal-organic chain structure with a 1D T4(0)A(4) water tape. Complexes 3 show a 2D grid-like sheet structure with the 1D water tape T4(0)A(0)2(0) motif. Complex 4 is a porous 3D MOF with tetrahedron-coordinated Cd(II) centers and trans-conformation PA-BIM ligands. These holes are occupied by a fascinating three-dimensional water clathrate network, which consists of cage-shaped structural tetradecameric water cluster (H2O)14 units and six independent bridged water molecules. The results suggest that the bisimidazolium ligands and anions play crucial roles in the formation of the different host structures and different guest water aggregations. Additionally, the thermal stabilities and photoluminescence spectra of the complexes have been discussed.
Russell Feder and Mahmoud Z. Yousef
2009-05-29
Neutronics analysis to find nuclear heating rates and personnel dose rates were conducted in support of the integration of diagnostics in to the ITER Upper Port Plugs. Simplified shielding models of the Visible-Infrared diagnostic and of the ECH heating system were incorporated in to the ITER global CAD model. Results for these systems are representative of typical designs with maximum shielding and a small aperture (Vis-IR) and minimal shielding with a large aperture (ECH). The neutronics discrete-ordinates code ATTILA® and SEVERIAN® (the ATTILA parallel processing version) was used. Material properties and the 500 MW D-T volume source were taken from the ITER “Brand Model” MCNP benchmark model. A biased quadrature set equivelant to Sn=32 and a scattering degree of Pn=3 were used along with a 46-neutron and 21-gamma FENDL energy subgrouping. Total nuclear heating (neutron plug gamma heating) in the upper port plugs ranged between 380 and 350 kW for the Vis-IR and ECH cases. The ECH or Large Aperture model exhibited lower total heating but much higher peak volumetric heating on the upper port plug structure. Personnel dose rates are calculated in a three step process involving a neutron-only transport calculation, the generation of activation volume sources at pre-defined time steps and finally gamma transport analyses are run for selected time steps. ANSI-ANS 6.1.1 1977 Flux-to-Dose conversion factors were used. Dose rates were evaluated for 1 full year of 500 MW DT operation which is comprised of 3000 1800-second pulses. After one year the machine is shut down for maintenance and personnel are permitted to access the diagnostic interspace after 2-weeks if dose rates are below 100 μSv/hr. Dose rates in the Visible-IR diagnostic model after one day of shutdown were 130 μSv/hr but fell below the limit to 90 μSv/hr 2-weeks later. The Large Aperture or ECH style shielding model exhibited higher and more persistent dose rates. After 1-day the dose rate was 230
NASA Astrophysics Data System (ADS)
Timofeev, V. Yu.; Kust, T. S.; Dronov, A. A.; Beloglazov, I. I.; Ikonnikov, D. A.
2016-08-01
A numerical experiment procedure of geokhod traverse in the geological environment, based on software PFC3D 5.00 is presented in the paper; the interpretation of numerical experiment results is provided.
The Transient 3-D Transport Coupled Code TORT-TD/ATTICA3D for High-Fidelity Pebble-Bed HTGR Analyses
NASA Astrophysics Data System (ADS)
Seubert, Armin; Sureda, Antonio; Lapins, Janis; Bader, Johannes; Laurien, Eckart
2012-01-01
This article describes the 3D discrete ordinates-based coupled code system TORT-TD/ATTICA3D that aims at steady state and transient analyses of pebble-bed high-temperature gas cooled reactors. In view of increasing computing power, the application of time-dependent neutron transport methods becomes feasible for best estimate evaluations of safety margins. The calculation capabilities of TORT-TD/ATTICA3D are presented along with the coupling approach, with focus on the time-dependent neutron transport features of TORT-TD. Results obtained for the OECD/NEA/NSC PBMR-400 benchmark demonstrate the transient capabilities of TORT-TD/ATTICA3D.
Computing Radiative Transfer in a 3D Medium
NASA Technical Reports Server (NTRS)
Von Allmen, Paul; Lee, Seungwon
2012-01-01
A package of software computes the time-dependent propagation of a narrow laser beam in an arbitrary three- dimensional (3D) medium with absorption and scattering, using the transient-discrete-ordinates method and a direct integration method. Unlike prior software that utilizes a Monte Carlo method, this software enables simulation at very small signal-to-noise ratios. The ability to simulate propagation of a narrow laser beam in a 3D medium is an improvement over other discrete-ordinate software. Unlike other direct-integration software, this software is not limited to simulation of propagation of thermal radiation with broad angular spread in three dimensions or of a laser pulse with narrow angular spread in two dimensions. Uses for this software include (1) computing scattering of a pulsed laser beam on a material having given elastic scattering and absorption profiles, and (2) evaluating concepts for laser-based instruments for sensing oceanic turbulence and related measurements of oceanic mixed-layer depths. With suitable augmentation, this software could be used to compute radiative transfer in ultrasound imaging in biological tissues, radiative transfer in the upper Earth crust for oil exploration, and propagation of laser pulses in telecommunication applications.
Hong, X; Gao, H
2014-06-15
Purpose: The Linear Boltzmann Transport Equation (LBTE) solved through statistical Monte Carlo (MC) method provides the accurate dose calculation in radiotherapy. This work is to investigate the alternative way for accurately solving LBTE using deterministic numerical method due to its possible advantage in computational speed from MC. Methods: Instead of using traditional spherical harmonics to approximate angular scattering kernel, our deterministic numerical method directly computes angular scattering weights, based on a new angular discretization method that utilizes linear finite element method on the local triangulation of unit angular sphere. As a Result, our angular discretization method has the unique advantage in positivity, i.e., to maintain all scattering weights nonnegative all the time, which is physically correct. Moreover, our method is local in angular space, and therefore handles the anisotropic scattering well, such as the forward-peaking scattering. To be compatible with image-guided radiotherapy, the spatial variables are discretized on the structured grid with the standard diamond scheme. After discretization, the improved sourceiteration method is utilized for solving the linear system without saving the linear system to memory. The accuracy of our 3D solver is validated using analytic solutions and benchmarked with Geant4, a popular MC solver. Results: The differences between Geant4 solutions and our solutions were less than 1.5% for various testing cases that mimic the practical cases. More details are available in the supporting document. Conclusion: We have developed a 3D LBTE solver based on a new angular discretization method that guarantees the positivity of scattering weights for physical correctness, and it has been benchmarked with Geant4 for photon dose calculation.
Slater, C.O.
1992-01-01
The DRC2 code, which couples MASH or MASHX adjoint leakages with DORT 2-D discrete ordinates forward directional fluences, is described. The forward fluences are allowed to vary both axially and radially over the coupling surface, as opposed to the strictly axial variation allowed by the predecessor DRC code. Input instructions are presented along with descriptions and results from several sample problems. Results from the sample problems are used to compare DRC2 with DRC, DRC2 with DORT, and DRC2 with itself for the case of x-y dependence versus no x-y dependence of the forward fluence. The test problems demonstrate that for small systems DRC and DRC2 give essentially the same results. Some significant differences are noted for larger systems. Additionally, DRC2 results with no x-y dependence of the forward directional fluences are practically the same as those calculated by DRC.
Zou, Guo-Dong; Wang, Ze-Ping; Song, Ying; Hu, Bing; Huang, Xiao-Ying
2014-07-14
Five novel praseodymium-antimony oxochloride (Pr-Sb-O-Cl) cluster-based compounds, namely (2-MepyH)2[Fe(1,10-phen)3]2[Pr4Sb12O18Cl14.6(OH)2.4(Hsal)]·H2O (1), (2-MepyH)2[Fe(1,10-phen)3]4{[Pr4Sb12O18Cl13.5(OH)0.5](bcpb)2[Pr4Sb12O18Cl13.5(OH)0.5]}·42H2O (2), (3-MepyH)2[Fe(1,10-phen)3]{[Pr4Sb12O18Cl13(H2O)2](bcpb)}·2(3-Mepy)·3H2O (3), [Fe(1,10-phen)3]2{[Pr4Sb12O18Cl10(H2O)2](bcpb)2}·3(3-Mepy)·13H2O (4), and (2-MepyH)6[Fe(1,10-phen)3]10{[Pr4Sb12O18Cl13(OH)2]2[Pr4Sb12O18Cl9][Pr4Sb12O18Cl9(OH)2]2(Hpdc)10(pdc)2}·110H2O (5) (2-Mepy = 2-methylpyridine, 3-Mepy = 3-methylpyridine, 1,10-phen = 1,10-phenanthroline, H2sal = salicylic acid, H3bcpb = 3,5-bis(4-carboxyphenoxy)benzoic acid, H3pdc = 3,5-pyrazoledicarboxylic acid) have been solvothermally synthesized and structurally characterized. Compound 1 is the first zero-dimensional (0D) Pr-Sb-O-Cl cluster decorated by an organic ligand. Compounds 2-4 are constructed from the same H3bcpb ligands but adopt different structures: 2 represents a rare example of a one-dimensional (1D) nanotubular structure based on high-nuclearity clusters; 3 exhibits a two-dimensional (2D) mono-layered structure, in which left-handed and right-handed helical chains are alternately arranged, while 4 features a double-layered structure with an unprecedented (3,3,6)-connected 3-nodal topological net. Compound 5 is a unique three-dimensional (3D) 2-fold interpenetrating racemic compound, simultaneously containing three kinds of Pr-Sb-O-Cl-pdc clusters. UV-light photocatalytic H2 evolution activity was observed for compound 3 with Pt as a co-catalyst and MeOH as a sacrificial electron donor. In addition, the magnetic properties of compounds 1 and 5 are also studied.
Zou, Guo-Dong; Wang, Ze-Ping; Song, Ying; Hu, Bing; Huang, Xiao-Ying
2014-07-14
Five novel praseodymium-antimony oxochloride (Pr-Sb-O-Cl) cluster-based compounds, namely (2-MepyH)2[Fe(1,10-phen)3]2[Pr4Sb12O18Cl14.6(OH)2.4(Hsal)]·H2O (1), (2-MepyH)2[Fe(1,10-phen)3]4{[Pr4Sb12O18Cl13.5(OH)0.5](bcpb)2[Pr4Sb12O18Cl13.5(OH)0.5]}·42H2O (2), (3-MepyH)2[Fe(1,10-phen)3]{[Pr4Sb12O18Cl13(H2O)2](bcpb)}·2(3-Mepy)·3H2O (3), [Fe(1,10-phen)3]2{[Pr4Sb12O18Cl10(H2O)2](bcpb)2}·3(3-Mepy)·13H2O (4), and (2-MepyH)6[Fe(1,10-phen)3]10{[Pr4Sb12O18Cl13(OH)2]2[Pr4Sb12O18Cl9][Pr4Sb12O18Cl9(OH)2]2(Hpdc)10(pdc)2}·110H2O (5) (2-Mepy = 2-methylpyridine, 3-Mepy = 3-methylpyridine, 1,10-phen = 1,10-phenanthroline, H2sal = salicylic acid, H3bcpb = 3,5-bis(4-carboxyphenoxy)benzoic acid, H3pdc = 3,5-pyrazoledicarboxylic acid) have been solvothermally synthesized and structurally characterized. Compound 1 is the first zero-dimensional (0D) Pr-Sb-O-Cl cluster decorated by an organic ligand. Compounds 2-4 are constructed from the same H3bcpb ligands but adopt different structures: 2 represents a rare example of a one-dimensional (1D) nanotubular structure based on high-nuclearity clusters; 3 exhibits a two-dimensional (2D) mono-layered structure, in which left-handed and right-handed helical chains are alternately arranged, while 4 features a double-layered structure with an unprecedented (3,3,6)-connected 3-nodal topological net. Compound 5 is a unique three-dimensional (3D) 2-fold interpenetrating racemic compound, simultaneously containing three kinds of Pr-Sb-O-Cl-pdc clusters. UV-light photocatalytic H2 evolution activity was observed for compound 3 with Pt as a co-catalyst and MeOH as a sacrificial electron donor. In addition, the magnetic properties of compounds 1 and 5 are also studied. PMID:24869770
NASA Technical Reports Server (NTRS)
Ghorai, S. K.
1983-01-01
The purpose of this project was to use a one-dimensional discrete coordinates transport code called ANISN in order to determine the energy-angle-spatial distribution of neutrons in a 6-feet cube rock box which houses a D-T neutron generator at its center. The project was two-fold. The first phase of the project involved adaptation of the ANISN code written for an IBM 360/75/91 computer to the UNIVAC system at JSC. The second phase of the project was to use the code with proper geometry, source function and rock material composition in order to determine the neutron flux distribution around the rock box when a 14.1 MeV neutron generator placed at its center is activated.
3D modeling of satellite spectral images, radiation budget and energy budget of urban landscapes
NASA Astrophysics Data System (ADS)
Gastellu-Etchegorry, J. P.
2008-12-01
DART EB is a model that is being developed for simulating the 3D (3 dimensional) energy budget of urban and natural scenes, possibly with topography and atmosphere. It simulates all non radiative energy mechanisms (heat conduction, turbulent momentum and heat fluxes, water reservoir evolution, etc.). It uses DART model (Discrete Anisotropic Radiative Transfer) for simulating radiative mechanisms: 3D radiative budget of 3D scenes and their remote sensing images expressed in terms of reflectance or brightness temperature values, for any atmosphere, wavelength, sun/view direction, altitude and spatial resolution. It uses an innovative multispectral approach (ray tracing, exact kernel, discrete ordinate techniques) over the whole optical domain. This paper presents two major and recent improvements of DART for adapting it to urban canopies. (1) Simulation of the geometry and optical characteristics of urban elements (houses, etc.). (2) Modeling of thermal infrared emission by vegetation and urban elements. The new DART version was used in the context of the CAPITOUL project. For that, districts of the Toulouse urban data base (Autocad format) were translated into DART scenes. This allowed us to simulate visible, near infrared and thermal infrared satellite images of Toulouse districts. Moreover, the 3D radiation budget was used by DARTEB for simulating the time evolution of a number of geophysical quantities of various surface elements (roads, walls, roofs). Results were successfully compared with ground measurements of the CAPITOUL project.
Graphical Models for Ordinal Data
Guo, Jian; Levina, Elizaveta; Michailidis, George; Zhu, Ji
2014-01-01
A graphical model for ordinal variables is considered, where it is assumed that the data are generated by discretizing the marginal distributions of a latent multivariate Gaussian distribution. The relationships between these ordinal variables are then described by the underlying Gaussian graphical model and can be inferred by estimating the corresponding concentration matrix. Direct estimation of the model is computationally expensive, but an approximate EM-like algorithm is developed to provide an accurate estimate of the parameters at a fraction of the computational cost. Numerical evidence based on simulation studies shows the strong performance of the algorithm, which is also illustrated on data sets on movie ratings and an educational survey. PMID:26120267
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2015-01-01
This manual describes the installation and execution of FUN3D version 12.7, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bill; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2016-01-01
This manual describes the installation and execution of FUN3D version 13.0, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, William L.; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2015-01-01
This manual describes the installation and execution of FUN3D version 12.6, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, William L.; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2014-01-01
This manual describes the installation and execution of FUN3D version 12.5, including optional dependent packages. FUN3D is a suite of computational uid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables ecient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2016-01-01
This manual describes the installation and execution of FUN3D version 12.9, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2015-01-01
This manual describes the installation and execution of FUN3D version 12.8, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2014-01-01
This manual describes the installation and execution of FUN3D version 12.4, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixedelement unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
NASA Astrophysics Data System (ADS)
Pletinckx, D.
2011-09-01
The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.
3d-3d correspondence revisited
NASA Astrophysics Data System (ADS)
Chung, Hee-Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr
2016-04-01
In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d {N}=2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. We also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.
3d-3d correspondence revisited
Chung, Hee -Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr
2016-04-21
In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d N = 2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. As a result, we also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.
NASA Astrophysics Data System (ADS)
Meulien Ohlmann, Odile
2013-02-01
Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?
ERIC Educational Resources Information Center
Ferrari, Pier Alda; Barbiero, Alessandro
2012-01-01
The increasing use of ordinal variables in different fields has led to the introduction of new statistical methods for their analysis. The performance of these methods needs to be investigated under a number of experimental conditions. Procedures to simulate from ordinal variables are then required. In this article, we deal with simulation from…
Advanced quadratures and periodic boundary conditions in parallel 3D S{sub n} transport
Manalo, K.; Yi, C.; Huang, M.; Sjoden, G.
2013-07-01
Significant updates in numerical quadratures have warranted investigation with 3D Sn discrete ordinates transport. We show new applications of quadrature departing from level symmetric (S{sub 2}o). investigating 3 recently developed quadratures: Even-Odd (EO), Linear-Discontinuous Finite Element - Surface Area (LDFE-SA), and the non-symmetric Icosahedral Quadrature (IC). We discuss implementation changes to 3D Sn codes (applied to Hybrid MOC-Sn TITAN and 3D parallel PENTRAN) that can be performed to accommodate Icosahedral Quadrature, as this quadrature is not 90-degree rotation invariant. In particular, as demonstrated using PENTRAN, the properties of Icosahedral Quadrature are suitable for trivial application using periodic BCs versus that of reflective BCs. In addition to implementing periodic BCs for 3D Sn PENTRAN, we implemented a technique termed 'angular re-sweep' which properly conditions periodic BCs for outer eigenvalue iterative loop convergence. As demonstrated by two simple transport problems (3-group fixed source and 3-group reflected/periodic eigenvalue pin cell), we remark that all of the quadratures we investigated are generally superior to level symmetric quadrature, with Icosahedral Quadrature performing the most efficiently for problems tested. (authors)
ERIC Educational Resources Information Center
Hastings, S. K.
2002-01-01
Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)
MRCK_3D contact detonation algorithm
Rougier, Esteban; Munjiza, Antonio
2010-01-01
Large-scale Combined Finite-Discrete Element Methods (FEM-DEM) and Discrete Element Methods (DEM) simulations involving contact of a large number of separate bod ies need an efficient, robust and flexible contact detection algorithm. In this work the MRCK-3D search algorithm is outlined and its main CPU perfonnances are evaluated. One of the most important aspects of this newly developed search algorithm is that it is applicable to systems consisting of many bodies of different shapes and sizes.
Reactor Dosimetry Applications Using RAPTOR-M3G:. a New Parallel 3-D Radiation Transport Code
NASA Astrophysics Data System (ADS)
Longoni, Gianluca; Anderson, Stanwood L.
2009-08-01
The numerical solution of the Linearized Boltzmann Equation (LBE) via the Discrete Ordinates method (SN) requires extensive computational resources for large 3-D neutron and gamma transport applications due to the concurrent discretization of the angular, spatial, and energy domains. This paper will discuss the development RAPTOR-M3G (RApid Parallel Transport Of Radiation - Multiple 3D Geometries), a new 3-D parallel radiation transport code, and its application to the calculation of ex-vessel neutron dosimetry responses in the cavity of a commercial 2-loop Pressurized Water Reactor (PWR). RAPTOR-M3G is based domain decomposition algorithms, where the spatial and angular domains are allocated and processed on multi-processor computer architectures. As compared to traditional single-processor applications, this approach reduces the computational load as well as the memory requirement per processor, yielding an efficient solution methodology for large 3-D problems. Measured neutron dosimetry responses in the reactor cavity air gap will be compared to the RAPTOR-M3G predictions. This paper is organized as follows: Section 1 discusses the RAPTOR-M3G methodology; Section 2 describes the 2-loop PWR model and the numerical results obtained. Section 3 addresses the parallel performance of the code, and Section 4 concludes this paper with final remarks and future work.
Coupling 2-D cylindrical and 3-D x-y-z transport computations
Abu-Shumays, I.K.; Yehnert, C.E.; Pitcairn, T.N.
1998-06-30
This paper describes a new two-dimensional (2-D) cylindrical geometry to three-dimensional (3-D) rectangular x-y-z splice option for multi-dimensional discrete ordinates solutions to the neutron (photon) transport equation. Of particular interest are the simple transformations developed and applied in order to carry out the required spatial and angular interpolations. The spatial interpolations are linear and equivalent to those applied elsewhere. The angular interpolations are based on a high order spherical harmonics representation of the angular flux. Advantages of the current angular interpolations over previous work are discussed. An application to an intricate streaming problem is provided to demonstrate the advantages of the new method for efficient and accurate prediction of particle behavior in complex geometries.
Kolmogorov-Sinai entropy from the ordinal viewpoint
NASA Astrophysics Data System (ADS)
Keller, Karsten; Sinn, Mathieu
2010-06-01
In the case of ergodicity much of the structure of a one-dimensional time-discrete dynamical system is already determined by its ordinal structure. We generally discuss this phenomenon by considering the distribution of ordinal patterns, which describe the ups and downs in the orbits of a Borel measurable map on a Borel subset of the real line. On this base, we give a natural ordinal description of the Kolmogorov-Sinai entropy of one-dimensional dynamical systems and relate the Kolmogorov-Sinai entropy to the permutation entropy recently introduced by Bandt and Pompe.
NASA Astrophysics Data System (ADS)
Oldham, Mark
2015-01-01
Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.
NASA Astrophysics Data System (ADS)
Moore, Gregory F.
2009-05-01
This volume is a brief introduction aimed at those who wish to gain a basic and relatively quick understanding of the interpretation of three-dimensional (3-D) seismic reflection data. The book is well written, clearly illustrated, and easy to follow. Enough elementary mathematics are presented for a basic understanding of seismic methods, but more complex mathematical derivations are avoided. References are listed for readers interested in more advanced explanations. After a brief introduction, the book logically begins with a succinct chapter on modern 3-D seismic data acquisition and processing. Standard 3-D acquisition methods are presented, and an appendix expands on more recent acquisition techniques, such as multiple-azimuth and wide-azimuth acquisition. Although this chapter covers the basics of standard time processing quite well, there is only a single sentence about prestack depth imaging, and anisotropic processing is not mentioned at all, even though both techniques are now becoming standard.
Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran
2016-03-17
We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.
Lighting ordinances: why? how?
NASA Astrophysics Data System (ADS)
Crawford, D. L.
1996-11-01
For those interested in combating the adverse effects of light pollution, both on astronomy and on the general public, one of the strongest "allies" is the existence of an outdoor lighting control ordinance. Such a law sets a community standard for good lighting, thus minimizing glare, light trespass, the clutter of bad lighting, and energy waste. The process of obtaining such an ordinance can be quite time consuming, but it has the added value of educating most of the segments of a community about the issues, and of building allies to the cause.
NASA Astrophysics Data System (ADS)
Plaut, J. J.
1993-08-01
Stereographic images of the surface of Venus which enable geologists to reconstruct the details of the planet's evolution are discussed. The 120-meter resolution of these 3D images make it possible to construct digital topographic maps from which precise measurements can be made of the heights, depths, slopes, and volumes of geologic structures.
Van, B.T.; Pajon, J.L.; Joseph, P. )
1991-11-01
This paper shows how some simple 3D computer graphics tools can be combined to provide efficient software for visualizing and analyzing data obtained from reservoir simulators and geological simulations. The animation and interactive capabilities of the software quickly provide a deep understanding of the fluid-flow behavior and an accurate idea of the internal architecture of a reservoir.
Conditional entropy of ordinal patterns
NASA Astrophysics Data System (ADS)
Unakafov, Anton M.; Keller, Karsten
2014-02-01
In this paper we investigate a quantity called conditional entropy of ordinal patterns, akin to the permutation entropy. The conditional entropy of ordinal patterns describes the average diversity of the ordinal patterns succeeding a given ordinal pattern. We observe that this quantity provides a good estimation of the Kolmogorov-Sinai entropy in many cases. In particular, the conditional entropy of ordinal patterns of a finite order coincides with the Kolmogorov-Sinai entropy for periodic dynamics and for Markov shifts over a binary alphabet. Finally, the conditional entropy of ordinal patterns is computationally simple and thus can be well applied to real-world data.
NASA Astrophysics Data System (ADS)
Isaksson, Folke; Borg, Johan; Haglund, Leif
2008-04-01
In this paper the performance of passive range measurement imaging using stereo technique in real time applications is described. Stereo vision uses multiple images to get depth resolution in a similar way as Synthetic Aperture Radar (SAR) uses multiple measurements to obtain better spatial resolution. This technique has been used in photogrammetry for a long time but it will be shown that it is now possible to do the calculations, with carefully designed image processing algorithms, in e.g. a PC in real time. In order to get high resolution and quantitative data in the stereo estimation a mathematical camera model is used. The parameters to the camera model are settled in a calibration rig or in the case of a moving camera the scene itself can be used for calibration of most of the parameters. After calibration an ordinary TV camera has an angular resolution like a theodolite, but to a much lower price. The paper will present results from high resolution 3D imagery from air to ground. The 3D-results from stereo calculation of image pairs are stitched together into a large database to form a 3D-model of the area covered.
Taming supersymmetric defects in 3d-3d correspondence
NASA Astrophysics Data System (ADS)
Gang, Dongmin; Kim, Nakwoo; Romo, Mauricio; Yamazaki, Masahito
2016-07-01
We study knots in 3d Chern-Simons theory with complex gauge group {SL}(N,{{C}}), in the context of its relation with 3d { N }=2 theory (the so-called 3d-3d correspondence). The defect has either co-dimension 2 or co-dimension 4 inside the 6d (2,0) theory, which is compactified on a 3-manifold \\hat{M}. We identify such defects in various corners of the 3d-3d correspondence, namely in 3d {SL}(N,{{C}}) CS theory, in 3d { N }=2 theory, in 5d { N }=2 super Yang-Mills theory, and in the M-theory holographic dual. We can make quantitative checks of the 3d-3d correspondence by computing partition functions at each of these theories. This Letter is a companion to a longer paper [1], which contains more details and more results.
NASA Technical Reports Server (NTRS)
1992-01-01
Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.
McGhee, J.M.; Roberts, R.M.; Morel, J.E.
1997-06-01
A spherical harmonics research code (DANTE) has been developed which is compatible with parallel computer architectures. DANTE provides 3-D, multi-material, deterministic, transport capabilities using an arbitrary finite element mesh. The linearized Boltzmann transport equation is solved in a second order self-adjoint form utilizing a Galerkin finite element spatial differencing scheme. The core solver utilizes a preconditioned conjugate gradient algorithm. Other distinguishing features of the code include options for discrete-ordinates and simplified spherical harmonics angular differencing, an exact Marshak boundary treatment for arbitrarily oriented boundary faces, in-line matrix construction techniques to minimize memory consumption, and an effective diffusion based preconditioner for scattering dominated problems. Algorithm efficiency is demonstrated for a massively parallel SIMD architecture (CM-5), and compatibility with MPP multiprocessor platforms or workstation clusters is anticipated.
CFL3D, FUN3d, and NSU3D Contributions to the Fifth Drag Prediction Workshop
NASA Technical Reports Server (NTRS)
Park, Michael A.; Laflin, Kelly R.; Chaffin, Mark S.; Powell, Nicholas; Levy, David W.
2013-01-01
Results presented at the Fifth Drag Prediction Workshop using CFL3D, FUN3D, and NSU3D are described. These are calculations on the workshop provided grids and drag adapted grids. The NSU3D results have been updated to reflect an improvement to skin friction calculation on skewed grids. FUN3D results generated after the workshop are included for custom participant generated grids and a grid from a previous workshop. Uniform grid refinement at the design condition shows a tight grouping in calculated drag, where the variation in the pressure component of drag is larger than the skin friction component. At this design condition, A fine-grid drag value was predicted with a smaller drag adjoint adapted grid via tetrahedral adaption to a metric and mixed-element subdivision. The buffet study produced larger variation than the design case, which is attributed to large differences in the predicted side-of-body separation extent. Various modeling and discretization approaches had a strong impact on predicted side-of-body separation. This large wing root separation bubble was not observed in wind tunnel tests indicating that more work is necessary in modeling wing root juncture flows to predict experiments.
3-D UNSTRUCTURED HEXAHEDRAL-MESH Sn TRANSPORT METHODS
J. MOREL; J. MCGHEE; ET AL
2000-11-01
This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). We have developed a method for solving the neutral-particle transport equation on 3-D unstructured hexahedral meshes using a S{sub n} discretization in angle in conjunction with a discontinuous finite-element discretization in space and a multigroup discretization in energy. Previous methods for solving this equation in 3-D have been limited to rectangular meshes. The unstructured-mesh method that we have developed is far more efficient for solving problems with complex 3-D geometric features than rectangular-mesh methods. In spite of having to make several compromises in our spatial discretization technique and our iterative solution technique, our method has been found to be both accurate and efficient for a broad class of problems.
3D-radiative transfer in terrestrial atmosphere: An efficient parallel numerical procedure
NASA Astrophysics Data System (ADS)
Bass, L. P.; Germogenova, T. A.; Nikolaeva, O. V.; Kokhanovsky, A. A.; Kuznetsov, V. S.
2003-04-01
Light propagation and scattering in terrestrial atmosphere is usually studied in the framework of the 1D radiative transfer theory [1]. However, in reality particles (e.g., ice crystals, solid and liquid aerosols, cloud droplets) are randomly distributed in 3D space. In particular, their concentrations vary both in vertical and horizontal directions. Therefore, 3D effects influence modern cloud and aerosol retrieval procedures, which are currently based on the 1D radiative transfer theory. It should be pointed out that the standard radiative transfer equation allows to study these more complex situations as well [2]. In recent year the parallel version of the 2D and 3D RADUGA code has been developed. This version is successfully used in gammas and neutrons transport problems [3]. Applications of this code to radiative transfer in atmosphere problems are contained in [4]. Possibilities of code RADUGA are presented in [5]. The RADUGA code system is an universal solver of radiative transfer problems for complicated models, including 2D and 3D aerosol and cloud fields with arbitrary scattering anisotropy, light absorption, inhomogeneous underlying surface and topography. Both delta type and distributed light sources can be accounted for in the framework of the algorithm developed. The accurate numerical procedure is based on the new discrete ordinate SWDD scheme [6]. The algorithm is specifically designed for parallel supercomputers. The version RADUGA 5.1(P) can run on MBC1000M [7] (768 processors with 10 Gb of hard disc memory for each processor). The peak productivity is equal 1 Tfl. Corresponding scalar version RADUGA 5.1 is working on PC. As a first example of application of the algorithm developed, we have studied the shadowing effects of clouds on neighboring cloudless atmosphere, depending on the cloud optical thickness, surface albedo, and illumination conditions. This is of importance for modern satellite aerosol retrieval algorithms development. [1] Sobolev
NASA Technical Reports Server (NTRS)
1997-01-01
Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. Wedge is at lower left; Shark, Half-Dome, and Pumpkin are at center. Flat Top, about four inches high, is at lower right. The horizon in the distance is one to two kilometers away.
Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.
Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right
NASA Technical Reports Server (NTRS)
2004-01-01
This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.
Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.
On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.
The image mosaic is about 6 centimeters (2.4 inches) across.
NASA Technical Reports Server (NTRS)
1997-01-01
This area of terrain near the Sagan Memorial Station was taken on Sol 3 by the Imager for Mars Pathfinder (IMP). 3D glasses are necessary to identify surface detail.
The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.' It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters.
Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.
Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right
Ordinal analysis of time series
NASA Astrophysics Data System (ADS)
Keller, K.; Sinn, M.
2005-10-01
In order to develop fast and robust methods for extracting qualitative information from non-linear time series, Bandt and Pompe have proposed to consider time series from the pure ordinal viewpoint. On the basis of counting ordinal patterns, which describe the up-and-down in a time series, they have introduced the concept of permutation entropy for quantifying the complexity of a system behind a time series. The permutation entropy only provides one detail of the ordinal structure of a time series. Here we present a method for extracting the whole ordinal information.
NASA Astrophysics Data System (ADS)
Davis, S.
2004-05-01
A principal means to prevent poor exterior lighting practices is a lighting control ordinance. It is an enforceable legal restriction on specific lighting practices that are deemed unacceptable by the government body having jurisdiction. Outdoor lighting codes have proven to be effective at reducing polluting and trespassing light. A well written exterior lighting code will permit all forms of necessary illumination at reasonable intensities, but will demand shielding and other measures to prevent trespass and light pollution. A good code will also apply to all forms of outdoor lighting, including streets, highways, and exterior signs, as well as the lighting on dwellings, commercial and industrial buildings and building sites. A good code can make exceptions for special uses, provided it complies with an effective standard. The IDA Model Lighting Ordinance is a response to these requests. It is intended as an aid to communities that are seeking to take control of their outdoor lighting, to "take back the night" that is being lost to careless and excessive use of night lighting.
3D holography: from discretum to continuum
NASA Astrophysics Data System (ADS)
Bonzom, Valentin; Dittrich, Bianca
2016-03-01
We study the one-loop partition function of 3D gravity without cosmological constant on the solid torus with arbitrary metric fluctuations on the boundary. To this end we employ the discrete approach of (quantum) Regge calculus. In contrast with similar calculations performed directly in the continuum, we work with a boundary at finite distance from the torus axis. We show that after taking the continuum limit on the boundary — but still keeping finite distance from the torus axis — the one-loop correction is the same as the one recently found in the continuum in Barnich et al. for an asymptotically flat boundary. The discrete approach taken here allows to identify the boundary degrees of freedom which are responsible for the non-trivial structure of the one-loop correction. We therefore calculate also the Hamilton-Jacobi function to quadratic order in the boundary fluctuations both in the discrete set-up and directly in the continuum theory. We identify a dual boundary field theory with a Liouville type coupling to the boundary metric. The discrete set-up allows again to identify the dual field with degrees of freedom associated to radial bulk edges attached to the boundary. Integrating out this dual field reproduces the (boundary diffeomorphism invariant part of the) quadratic order of the Hamilton-Jacobi functional. The considerations here show that bulk boundary dualities might also emerge at finite boundaries and moreover that discrete approaches are helpful in identifying such dualities.
NASA Technical Reports Server (NTRS)
2009-01-01
wavelengths. Since the amount of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through.
The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave.
This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron.
High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these
NASA Astrophysics Data System (ADS)
Becker, J. K.; Bons, P. D.
2009-04-01
Microstructures of rocks play an important role in determining rheological properties and help to reveal the processes that lead to their formation. Some of these processes change the microstructure significantly and may thus have the opposite effect in obliterating any fabrics indicative of the previous history of the rocks. One of these processes is grain boundary migration (GBM). During static recrystallisation, GBM may produce a foam texture that completely overprints a pre-existing grain boundary network and GBM actively influences the rheology of a rock, via its influence on grain size and lattice defect concentration. We here present a new numerical simulation software that is capable of simulating a whole range of processes on the grain scale (it is not limited to grain boundary migration). The software is polyhedron-based, meaning that each grain (or phase) is represented by a polyhedron that has discrete boundaries. The boundary (the shell) of the polyhedron is defined by a set of facets which in turn is defined by a set of vertices. Each structural entity (polyhedron, facets and vertices) can have an unlimited number of parameters (depending on the process to be modeled) such as surface energy, concentration, etc. which can be used to calculate changes of the microstructre. We use the processes of grain boundary migration of a "regular" and a partially molten rock to demonstrate the software. Since this software is 3D, the formation of melt networks in a partially molten rock can also be studied. The interconnected melt network is of fundamental importance for melt segregation and migration in the crust and mantle and can help to understand the core-mantle differentiation of large terrestrial planets.
NASA Technical Reports Server (NTRS)
2009-01-01
wavelengths. Since the amount of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through.
The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave.
This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron.
High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these
3D Elevation Program—Virtual USA in 3D
Lukas, Vicki; Stoker, J.M.
2016-01-01
The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.
3D Elevation Program—Virtual USA in 3D
Lukas, Vicki; Stoker, J.M.
2016-04-14
The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.
Ordinal measures for iris recognition.
Sun, Zhenan; Tan, Tieniu
2009-12-01
Images of a human iris contain rich texture information useful for identity authentication. A key and still open issue in iris recognition is how best to represent such textural information using a compact set of features (iris features). In this paper, we propose using ordinal measures for iris feature representation with the objective of characterizing qualitative relationships between iris regions rather than precise measurements of iris image structures. Such a representation may lose some image-specific information, but it achieves a good trade-off between distinctiveness and robustness. We show that ordinal measures are intrinsic features of iris patterns and largely invariant to illumination changes. Moreover, compactness and low computational complexity of ordinal measures enable highly efficient iris recognition. Ordinal measures are a general concept useful for image analysis and many variants can be derived for ordinal feature extraction. In this paper, we develop multilobe differential filters to compute ordinal measures with flexible intralobe and interlobe parameters such as location, scale, orientation, and distance. Experimental results on three public iris image databases demonstrate the effectiveness of the proposed ordinal feature models. PMID:19834142
3D unstructured mesh discontinuous finite element hydro
Prasad, M.K.; Kershaw, D.S.; Shaw, M.J.
1995-07-01
The authors present detailed features of the ICF3D hydrodynamics code used for inertial fusion simulations. This code is intended to be a state-of-the-art upgrade of the well-known fluid code, LASNEX. ICF3D employs discontinuous finite elements on a discrete unstructured mesh consisting of a variety of 3D polyhedra including tetrahedra, prisms, and hexahedra. The authors discussed details of how the ROE-averaged second-order convection was applied on the discrete elements, and how the C++ coding interface has helped to simplify implementing the many physics and numerics modules within the code package. The author emphasized the virtues of object-oriented design in large scale projects such as ICF3D.
Laser printing of 3D metallic interconnects
NASA Astrophysics Data System (ADS)
Beniam, Iyoel; Mathews, Scott A.; Charipar, Nicholas A.; Auyeung, Raymond C. Y.; Piqué, Alberto
2016-04-01
The use of laser-induced forward transfer (LIFT) techniques for the printing of functional materials has been demonstrated for numerous applications. The printing gives rise to patterns, which can be used to fabricate planar interconnects. More recently, various groups have demonstrated electrical interconnects from laser-printed 3D structures. The laser printing of these interconnects takes place through aggregation of voxels of either molten metal or of pastes containing dispersed metallic particles. However, the generated 3D structures do not posses the same metallic conductivity as a bulk metal interconnect of the same cross-section and length as those formed by wire bonding or tab welding. An alternative is to laser transfer entire 3D structures using a technique known as lase-and-place. Lase-and-place is a LIFT process whereby whole components and parts can be transferred from a donor substrate onto a desired location with one single laser pulse. This paper will describe the use of LIFT to laser print freestanding, solid metal foils or beams precisely over the contact pads of discrete devices to interconnect them into fully functional circuits. Furthermore, this paper will also show how the same laser can be used to bend or fold the bulk metal foils prior to transfer, thus forming compliant 3D structures able to provide strain relief for the circuits under flexing or during motion from thermal mismatch. These interconnect "ridges" can span wide gaps (on the order of a millimeter) and accommodate height differences of tens of microns between adjacent devices. Examples of these laser printed 3D metallic bridges and their role in the development of next generation electronics by additive manufacturing will be presented.
NASA Technical Reports Server (NTRS)
1977-01-01
A market study of a proposed version of a 3-D eyetracker for initial use at NASA's Ames Research Center was made. The commercialization potential of a simplified, less expensive 3-D eyetracker was ascertained. Primary focus on present and potential users of eyetrackers, as well as present and potential manufacturers has provided an effective means of analyzing the prospects for commercialization.
None
2016-07-12
This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.
2013-10-30
This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.
2013-10-01
Earth3D is a computer code designed to allow fast calculation of seismic rays and travel times through a 3D model of the Earth. LLNL is using this for earthquake location and global tomography efforts and such codes are of great interest to the Earth Science community.
[3-D ultrasound in gastroenterology].
Zoller, W G; Liess, H
1994-06-01
Three-dimensional (3D) sonography represents a development of noninvasive diagnostic imaging by real-time two-dimensional (2D) sonography. The use of transparent rotating scans, comparable to a block of glass, generates a 3D effect. The objective of the present study was to optimate 3D presentation of abdominal findings. Additional investigations were made with a new volumetric program to determine the volume of selected findings of the liver. The results were compared with the estimated volumes of 2D sonography and 2D computer tomography (CT). For the processing of 3D images, typical parameter constellations were found for the different findings, which facilitated processing of 3D images. In more than 75% of the cases examined we found an optimal 3D presentation of sonographic findings with respect to the evaluation criteria developed by us for the 3D imaging of processed data. Great differences were found for the estimated volumes of the findings of the liver concerning the three different techniques applied. 3D ultrasound represents a valuable method to judge morphological appearance in abdominal findings. The possibility of volumetric measurements enlarges its potential diagnostic significance. Further clinical investigations are necessary to find out if definite differentiation between benign and malign findings is possible.
NASA Astrophysics Data System (ADS)
Walsh, J. R.
2004-02-01
The Euro3D RTN is an EU funded Research Training Network to foster the exploitation of 3D spectroscopy in Europe. 3D spectroscopy is a general term for spectroscopy of an area of the sky and derives its name from its two spatial + one spectral dimensions. There are an increasing number of instruments which use integral field devices to achieve spectroscopy of an area of the sky, either using lens arrays, optical fibres or image slicers, to pack spectra of multiple pixels on the sky (``spaxels'') onto a 2D detector. On account of the large volume of data and the special methods required to reduce and analyse 3D data, there are only a few centres of expertise and these are mostly involved with instrument developments. There is a perceived lack of expertise in 3D spectroscopy spread though the astronomical community and its use in the armoury of the observational astronomer is viewed as being highly specialised. For precisely this reason the Euro3D RTN was proposed to train young researchers in this area and develop user tools to widen the experience with this particular type of data in Europe. The Euro3D RTN is coordinated by Martin M. Roth (Astrophysikalisches Institut Potsdam) and has been running since July 2002. The first Euro3D science conference was held in Cambridge, UK from 22 to 23 May 2003. The main emphasis of the conference was, in keeping with the RTN, to expose the work of the young post-docs who are funded by the RTN. In addition the team members from the eleven European institutes involved in Euro3D also presented instrumental and observational developments. The conference was organized by Andy Bunker and held at the Institute of Astronomy. There were over thirty participants and 26 talks covered the whole range of application of 3D techniques. The science ranged from Galactic planetary nebulae and globular clusters to kinematics of nearby galaxies out to objects at high redshift. Several talks were devoted to reporting recent observations with newly
Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A
2015-12-01
3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery. PMID:26657435
NASA Technical Reports Server (NTRS)
Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.
1990-01-01
PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.
Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A
2015-12-01
3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.
PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)
NASA Technical Reports Server (NTRS)
Buning, P.
1994-01-01
PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into
PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)
NASA Technical Reports Server (NTRS)
Buning, P.
1994-01-01
PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into
Prediction of 3-D boundary layer in the curved inlets
NASA Astrophysics Data System (ADS)
Xing, Zongwen; Wang, Jianmin
1992-06-01
A prediction method for 3D compressible turbulent boundary layers in curved inlets is investigated. 3D boundary layer integral equations in nonorthogonal curvilinear coordinate system are used and solved by lag-entrainment method with an introduced 3D entrainment coefficient equation. During numerical calculation, the prediction corrector method is employed. With the cubic spline function, the interpolation and differentiation accuracy and smoothness of discrete data is ensured. The developed program may be operated on a personal computer. The influence of cross flow on boundary layer development is clearly shown by the calculated results. The calculated pressure recovery of the inlet is in good agreement with experiment data.
S3D: An interactive surface grid generation tool
NASA Technical Reports Server (NTRS)
Luh, Raymond Ching-Chung; Pierce, Lawrence E.; Yip, David
1992-01-01
S3D, an interactive software tool for surface grid generation, is described. S3D provides the means with which a geometry definition based either on a discretized curve set or a rectangular set can be quickly processed towards the generation of a surface grid for computational fluid dynamics (CFD) applications. This is made possible as a result of implementing commonly encountered surface gridding tasks in an environment with a highly efficient and user friendly graphical interface. Some of the more advanced features of S3D include surface-surface intersections, optimized surface domain decomposition and recomposition, and automated propagation of edge distributions to surrounding grids.
Wind Energy Ordinance Fact Sheet
F. Oteri
2010-09-01
Due to increasing energy demands in the United States and more installed wind projects, rural communities and local governments with limited or no experience with wind energy now have the opportunity to become involved in this industry. Communities with good wind resources may be approached by entities with plans to develop the resource. Although these opportunities can create new revenue in the form of construction jobs and land lease payments, they also create a new responsibility on the part of local governments to create ordinances to regulate wind turbine installations. Ordinances are laws, often found within municipal codes that provide various degrees of control to local governments. These laws cover issues such as zoning, traffic, consumer protection, and building codes. Wind energy ordinances reflect local needs and wants regarding wind turbines within county or city lines and aid the development of safe facilities that will be embraced by the community. Since 2008 when the National Renewable Energy Laboratory released a report on existing wind energy ordinances, many more ordinances have been established throughout the United States, and this trend is likely to continue in the near future as the wind energy industry grows. This fact sheet provides an overview of elements found in typical wind energy ordinances to educate state and local government officials, as well as policy makers.
Wind Energy Ordinances (Fact Sheet)
Not Available
2010-08-01
Due to increasing energy demands in the United States and more installed wind projects, rural communities and local governments with limited or no experience with wind energy now have the opportunity to become involved in this industry. Communities with good wind resources may be approached by entities with plans to develop the resource. Although these opportunities can create new revenue in the form of construction jobs and land lease payments, they also create a new responsibility on the part of local governments to create ordinances to regulate wind turbine installations. Ordinances are laws, often found within municipal codes that provide various degrees of control to local governments. These laws cover issues such as zoning, traffic, consumer protection, and building codes. Wind energy ordinances reflect local needs and wants regarding wind turbines within county or city lines and aid the development of safe facilities that will be embraced by the community. Since 2008 when the National Renewable Energy Laboratory released a report on existing wind energy ordinances, many more ordinances have been established throughout the United States, and this trend is likely to continue in the near future as the wind energy industry grows. This fact sheet provides an overview of elements found in typical wind energy ordinances to educate state and local government officials, as well as policy makers.
Unassisted 3D camera calibration
NASA Astrophysics Data System (ADS)
Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.
2012-03-01
With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.
FURN3D: A computer code for radiative heat transfer in pulverized coal furnaces
Ahluwalia, R.K.; Im, K.H.
1992-08-01
A computer code FURN3D has been developed for assessing the impact of burning different coals on heat absorption pattern in pulverized coal furnaces. The code is unique in its ability to conduct detailed spectral calculations of radiation transport in furnaces fully accounting for the size distributions of char, soot and ash particles, ash content, and ash composition. The code uses a hybrid technique of solving the three-dimensional radiation transport equation for absorbing, emitting and anisotropically scattering media. The technique achieves an optimal mix of computational speed and accuracy by combining the discrete ordinate method (S[sub 4]), modified differential approximation (MDA) and P, approximation in different range of optical thicknesses. The code uses spectroscopic data for estimating the absorption coefficients of participating gases C0[sub 2], H[sub 2]0 and CO. It invokes Mie theory for determining the extinction and scattering coefficients of combustion particulates. The optical constants of char, soot and ash are obtained from dispersion relations derived from reflectivity, transmissivity and extinction measurements. A control-volume formulation is adopted for determining the temperature field inside the furnace. A simple char burnout model is employed for estimating heat release and evolution of particle size distribution. The code is written in Fortran 77, has modular form, and is machine-independent. The computer memory required by the code depends upon the number of grid points specified and whether the transport calculations are performed on spectral or gray basis.
FURN3D: A computer code for radiative heat transfer in pulverized coal furnaces
Ahluwalia, R.K.; Im, K.H.
1992-08-01
A computer code FURN3D has been developed for assessing the impact of burning different coals on heat absorption pattern in pulverized coal furnaces. The code is unique in its ability to conduct detailed spectral calculations of radiation transport in furnaces fully accounting for the size distributions of char, soot and ash particles, ash content, and ash composition. The code uses a hybrid technique of solving the three-dimensional radiation transport equation for absorbing, emitting and anisotropically scattering media. The technique achieves an optimal mix of computational speed and accuracy by combining the discrete ordinate method (S{sub 4}), modified differential approximation (MDA) and P, approximation in different range of optical thicknesses. The code uses spectroscopic data for estimating the absorption coefficients of participating gases C0{sub 2}, H{sub 2}0 and CO. It invokes Mie theory for determining the extinction and scattering coefficients of combustion particulates. The optical constants of char, soot and ash are obtained from dispersion relations derived from reflectivity, transmissivity and extinction measurements. A control-volume formulation is adopted for determining the temperature field inside the furnace. A simple char burnout model is employed for estimating heat release and evolution of particle size distribution. The code is written in Fortran 77, has modular form, and is machine-independent. The computer memory required by the code depends upon the number of grid points specified and whether the transport calculations are performed on spectral or gray basis.
3D unstructured-mesh radiation transport codes
Morel, J.
1997-12-31
Three unstructured-mesh radiation transport codes are currently being developed at Los Alamos National Laboratory. The first code is ATTILA, which uses an unstructured tetrahedral mesh in conjunction with standard Sn (discrete-ordinates) angular discretization, standard multigroup energy discretization, and linear-discontinuous spatial differencing. ATTILA solves the standard first-order form of the transport equation using source iteration in conjunction with diffusion-synthetic acceleration of the within-group source iterations. DANTE is designed to run primarily on workstations. The second code is DANTE, which uses a hybrid finite-element mesh consisting of arbitrary combinations of hexahedra, wedges, pyramids, and tetrahedra. DANTE solves several second-order self-adjoint forms of the transport equation including the even-parity equation, the odd-parity equation, and a new equation called the self-adjoint angular flux equation. DANTE also offers three angular discretization options: $S{_}n$ (discrete-ordinates), $P{_}n$ (spherical harmonics), and $SP{_}n$ (simplified spherical harmonics). DANTE is designed to run primarily on massively parallel message-passing machines, such as the ASCI-Blue machines at LANL and LLNL. The third code is PERICLES, which uses the same hybrid finite-element mesh as DANTE, but solves the standard first-order form of the transport equation rather than a second-order self-adjoint form. DANTE uses a standard $S{_}n$ discretization in angle in conjunction with trilinear-discontinuous spatial differencing, and diffusion-synthetic acceleration of the within-group source iterations. PERICLES was initially designed to run on workstations, but a version for massively parallel message-passing machines will be built. The three codes will be described in detail and computational results will be presented.
NASA Astrophysics Data System (ADS)
Haefner, David P.; Preece, Bradley L.; Doe, Joshua M.; Burks, Stephen D.
2016-05-01
When evaluated with a spatially uniform irradiance, an imaging sensor exhibits both spatial and temporal variations, which can be described as a three-dimensional (3D) random process considered as noise. In the 1990s, NVESD engineers developed an approximation to the 3D power spectral density (PSD) for noise in imaging systems known as 3D noise. In this correspondence, we describe how the confidence intervals for the 3D noise measurement allows for determination of the sampling necessary to reach a desired precision. We then apply that knowledge to create a smaller cube that can be evaluated spatially across the 2D image giving the noise as a function of position. The method presented here allows for both defective pixel identification and implements the finite sampling correction matrix. In support of the reproducible research effort, the Matlab functions associated with this work can be found on the Mathworks file exchange [1].
NASA Astrophysics Data System (ADS)
Lee-Elkin, Forest
2008-04-01
Three dimensional (3D) autofocus remains a significant challenge for the development of practical 3D multipass radar imaging. The current 2D radar autofocus methods are not readily extendable across sensor passes. We propose a general framework that allows a class of data adaptive solutions for 3D auto-focus across passes with minimal constraints on the scene contents. The key enabling assumption is that portions of the scene are sparse in elevation which reduces the number of free variables and results in a system that is simultaneously solved for scatterer heights and autofocus parameters. The proposed method extends 2-pass interferometric synthetic aperture radar (IFSAR) methods to an arbitrary number of passes allowing the consideration of scattering from multiple height locations. A specific case from the proposed autofocus framework is solved and demonstrates autofocus and coherent multipass 3D estimation across the 8 passes of the "Gotcha Volumetric SAR Data Set" X-Band radar data.
Rich, D.O.; Pope, S.C.; DeLapp, J.G.
1994-10-01
In April, a 128 PE Cray T3D was installed at Los Alamos National Laboratory`s Advanced Computing Laboratory as part of the DOE`s High-Performance Parallel Processor Program (H4P). In conjunction with CRI, the authors implemented a 30 day acceptance test. The test was constructed in part to help them understand the strengths and weaknesses of the T3D. In this paper, they briefly describe the H4P and its goals. They discuss the design and implementation of the T3D acceptance test and detail issues that arose during the test. They conclude with a set of system requirements that must be addressed as the T3D system evolves.
Combinatorial 3D Mechanical Metamaterials
NASA Astrophysics Data System (ADS)
Coulais, Corentin; Teomy, Eial; de Reus, Koen; Shokef, Yair; van Hecke, Martin
2015-03-01
We present a class of elastic structures which exhibit 3D-folding motion. Our structures consist of cubic lattices of anisotropic unit cells that can be tiled in a complex combinatorial fashion. We design and 3d-print this complex ordered mechanism, in which we combine elastic hinges and defects to tailor the mechanics of the material. Finally, we use this large design space to encode smart functionalities such as surface patterning and multistability.
LASTRAC.3d: Transition Prediction in 3D Boundary Layers
NASA Technical Reports Server (NTRS)
Chang, Chau-Lyan
2004-01-01
Langley Stability and Transition Analysis Code (LASTRAC) is a general-purpose, physics-based transition prediction code released by NASA for laminar flow control studies and transition research. This paper describes the LASTRAC extension to general three-dimensional (3D) boundary layers such as finite swept wings, cones, or bodies at an angle of attack. The stability problem is formulated by using a body-fitted nonorthogonal curvilinear coordinate system constructed on the body surface. The nonorthogonal coordinate system offers a variety of marching paths and spanwise waveforms. In the extreme case of an infinite swept wing boundary layer, marching with a nonorthogonal coordinate produces identical solutions to those obtained with an orthogonal coordinate system using the earlier release of LASTRAC. Several methods to formulate the 3D parabolized stability equations (PSE) are discussed. A surface-marching procedure akin to that for 3D boundary layer equations may be used to solve the 3D parabolized disturbance equations. On the other hand, the local line-marching PSE method, formulated as an easy extension from its 2D counterpart and capable of handling the spanwise mean flow and disturbance variation, offers an alternative. A linear stability theory or parabolized stability equations based N-factor analysis carried out along the streamline direction with a fixed wavelength and downstream-varying spanwise direction constitutes an efficient engineering approach to study instability wave evolution in a 3D boundary layer. The surface-marching PSE method enables a consistent treatment of the disturbance evolution along both streamwise and spanwise directions but requires more stringent initial conditions. Both PSE methods and the traditional LST approach are implemented in the LASTRAC.3d code. Several test cases for tapered or finite swept wings and cones at an angle of attack are discussed.
NASA Astrophysics Data System (ADS)
Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.
2014-08-01
In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers
YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters
NASA Astrophysics Data System (ADS)
Schild, Jonas; Seele, Sven; Masuch, Maic
2012-03-01
Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.
Remote 3D Medical Consultation
NASA Astrophysics Data System (ADS)
Welch, Greg; Sonnenwald, Diane H.; Fuchs, Henry; Cairns, Bruce; Mayer-Patel, Ketan; Yang, Ruigang; State, Andrei; Towles, Herman; Ilie, Adrian; Krishnan, Srinivas; Söderholm, Hanna M.
Two-dimensional (2D) video-based telemedical consultation has been explored widely in the past 15-20 years. Two issues that seem to arise in most relevant case studies are the difficulty associated with obtaining the desired 2D camera views, and poor depth perception. To address these problems we are exploring the use of a small array of cameras to synthesize a spatially continuous range of dynamic three-dimensional (3D) views of a remote environment and events. The 3D views can be sent across wired or wireless networks to remote viewers with fixed displays or mobile devices such as a personal digital assistant (PDA). The viewpoints could be specified manually or automatically via user head or PDA tracking, giving the remote viewer virtual head- or hand-slaved (PDA-based) remote cameras for mono or stereo viewing. We call this idea remote 3D medical consultation (3DMC). In this article we motivate and explain the vision for 3D medical consultation; we describe the relevant computer vision/graphics, display, and networking research; we present a proof-of-concept prototype system; and we present some early experimental results supporting the general hypothesis that 3D remote medical consultation could offer benefits over conventional 2D televideo.
NASA Technical Reports Server (NTRS)
2002-01-01
In 1999, Genex submitted a proposal to Stennis Space Center for a volumetric 3-D display technique that would provide multiple users with a 360-degree perspective to simultaneously view and analyze 3-D data. The futuristic capabilities of the VolumeViewer(R) have offered tremendous benefits to commercial users in the fields of medicine and surgery, air traffic control, pilot training and education, computer-aided design/computer-aided manufacturing, and military/battlefield management. The technology has also helped NASA to better analyze and assess the various data collected by its satellite and spacecraft sensors. Genex capitalized on its success with Stennis by introducing two separate products to the commercial market that incorporate key elements of the 3-D display technology designed under an SBIR contract. The company Rainbow 3D(R) imaging camera is a novel, three-dimensional surface profile measurement system that can obtain a full-frame 3-D image in less than 1 second. The third product is the 360-degree OmniEye(R) video system. Ideal for intrusion detection, surveillance, and situation management, this unique camera system offers a continuous, panoramic view of a scene in real time.
Au, Anthony K; Huynh, Wilson; Horowitz, Lisa F; Folch, Albert
2016-03-14
The advent of soft lithography allowed for an unprecedented expansion in the field of microfluidics. However, the vast majority of PDMS microfluidic devices are still made with extensive manual labor, are tethered to bulky control systems, and have cumbersome user interfaces, which all render commercialization difficult. On the other hand, 3D printing has begun to embrace the range of sizes and materials that appeal to the developers of microfluidic devices. Prior to fabrication, a design is digitally built as a detailed 3D CAD file. The design can be assembled in modules by remotely collaborating teams, and its mechanical and fluidic behavior can be simulated using finite-element modeling. As structures are created by adding materials without the need for etching or dissolution, processing is environmentally friendly and economically efficient. We predict that in the next few years, 3D printing will replace most PDMS and plastic molding techniques in academia.
3D Computations and Experiments
Couch, R; Faux, D; Goto, D; Nikkel, D
2004-04-05
This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.
Discrete elements method of neutral particle transport
Mathews, K.A.
1983-01-01
A new discrete elements (L/sub N/) transport method is derived and compared to the discrete ordinates S/sub N/ method, theoretically and by numerical experimentation. The discrete elements method is more accurate than discrete ordinates and strongly ameliorates ray effects for the practical problems studied. The discrete elements method is shown to be more cost effective, in terms of execution time with comparable storage to attain the same accuracy, for a one-dimensional test case using linear characteristic spatial quadrature. In a two-dimensional test case, a vacuum duct in a shield, L/sub N/ is more consistently convergent toward a Monte Carlo benchmark solution than S/sub N/, using step characteristic spatial quadrature. An analysis of the interaction of angular and spatial quadrature in xy-geometry indicates the desirability of using linear characteristic spatial quadrature with the L/sub N/ method.
Summary on Several Key Techniques in 3D Geological Modeling
2014-01-01
Several key techniques in 3D geological modeling including planar mesh generation, spatial interpolation, and surface intersection are summarized in this paper. Note that these techniques are generic and widely used in various applications but play a key role in 3D geological modeling. There are two essential procedures in 3D geological modeling: the first is the simulation of geological interfaces using geometric surfaces and the second is the building of geological objects by means of various geometric computations such as the intersection of surfaces. Discrete geometric surfaces that represent geological interfaces can be generated by creating planar meshes first and then spatially interpolating; those surfaces intersect and then form volumes that represent three-dimensional geological objects such as rock bodies. In this paper, the most commonly used algorithms of the key techniques in 3D geological modeling are summarized. PMID:24772029
Madsen, N.; Steich, D.; Cook, G.; Eme, B.
1995-03-16
The DSI3D-RCS code is designed to numerically evaluate radar cross sections on complex objects by solving Maxwell`s curl equations in the time-domain and in three space dimensions. The code has been designed to run on the new parallel processing computers as well as on conventional serial computers. The DSI3D-RCS code is unique for the following reasons: Allows the use of unstructured non-orthogonal grids, allows a variety of cell or element types, reduces to be the Finite Difference Time Domain (FDTD) method when orthogonal grids are used, preserves charge or divergence locally (and globally), is conditionally stable, is non-dissipative, is accurate for non-orthogonal grids. This method is derived using a Discrete Surface Integration (DSI) technique. As formulated, the DSI technique can be used with essentially arbitrary unstructured grids composed of convex polyhedral cells. This implementation of the DSI algorithm allows the use of unstructured grids that are composed of combinations of non-orthogonal hexahedrons, tetrahedrons, triangular prisms and pyramids. This algorithm reduces to the conventional FDTD method when applied on a structured orthogonal hexahedral grid.
Ordinal classification for efficient plant stress prediction in hyperspectral data
NASA Astrophysics Data System (ADS)
Behmann, J.; Schmitter, P.; Steinrücken, J.; Plümer, L.
2014-09-01
Detection of crop stress from hyperspectral images is of high importance for breeding and precision crop protection. However, the continuous monitoring of stress in phenotyping facilities by hyperspectral imagers produces huge amounts of uninterpreted data. In order to derive a stress description from the images, interpreting algorithms with high prediction performance are required. Based on a static model, the local stress state of each pixel has to be predicted. Due to the low computational complexity, linear models are preferable. In this paper, we focus on drought-induced stress which is represented by discrete stages of ordinal order. We present and compare five methods which are able to derive stress levels from hyperspectral images: One-vs.-one Support Vector Machine (SVM), one-vs.-all SVM, Support Vector Regression (SVR), Support Vector Ordinal Regression (SVORIM) and Linear Ordinal SVM classification. The methods are applied on two data sets - a real world set of drought stress in single barley plants and a simulated data set. It is shown, that Linear Ordinal SVM is a powerful tool for applications which require high prediction performance under limited resources. It is significantly more efficient than the one-vs.-one SVM and even more efficient than the less accurate one-vs.-all SVM. Compared to the very compact SVORIM model, it represents the senescence process much more accurate.
ERIC Educational Resources Information Center
Manos, Harry
2016-01-01
Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…
2007-07-20
This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial featuresmore » of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.« less
Russ, Trina; Koch, Mark; Koudelka, Melissa; Peters, Ralph; Little, Charles; Boehnen, Chris; Peters, Tanya
2007-07-20
This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial features of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.
3D Printing: Exploring Capabilities
ERIC Educational Resources Information Center
Samuels, Kyle; Flowers, Jim
2015-01-01
As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…
Spatial Representation of Ordinal Information
Zhang, Meng; Gao, Xuefei; Li, Baichen; Yu, Shuyuan; Gong, Tianwei; Jiang, Ting; Hu, Qingfen; Chen, Yinghe
2016-01-01
Right hand responds faster than left hand when shown larger numbers and vice-versa when shown smaller numbers (the SNARC effect). Accumulating evidence suggests that the SNARC effect may not be exclusive for numbers and can be extended to other ordinal sequences (e.g., months or letters in the alphabet) as well. In this study, we tested the SNARC effect with a non-numerically ordered sequence: the Chinese notations for the color spectrum (Red, Orange, Yellow, Green, Blue, Indigo, and Violet). Chinese color word sequence reserves relatively weak ordinal information, because each element color in the sequence normally appears in non-sequential contexts, making it ideal to test the spatial organization of sequential information that was stored in the long-term memory. This study found a reliable SNARC-like effect for Chinese color words (deciding whether the presented color word was before or after the reference color word “green”), suggesting that, without access to any quantitative information or exposure to any previous training, ordinal representation can still activate a sense of space. The results support that weak ordinal information without quantitative magnitude encoded in the long-term memory can activate spatial representation in a comparison task. PMID:27092100
Spatial Representation of Ordinal Information.
Zhang, Meng; Gao, Xuefei; Li, Baichen; Yu, Shuyuan; Gong, Tianwei; Jiang, Ting; Hu, Qingfen; Chen, Yinghe
2016-01-01
Right hand responds faster than left hand when shown larger numbers and vice-versa when shown smaller numbers (the SNARC effect). Accumulating evidence suggests that the SNARC effect may not be exclusive for numbers and can be extended to other ordinal sequences (e.g., months or letters in the alphabet) as well. In this study, we tested the SNARC effect with a non-numerically ordered sequence: the Chinese notations for the color spectrum (Red, Orange, Yellow, Green, Blue, Indigo, and Violet). Chinese color word sequence reserves relatively weak ordinal information, because each element color in the sequence normally appears in non-sequential contexts, making it ideal to test the spatial organization of sequential information that was stored in the long-term memory. This study found a reliable SNARC-like effect for Chinese color words (deciding whether the presented color word was before or after the reference color word "green"), suggesting that, without access to any quantitative information or exposure to any previous training, ordinal representation can still activate a sense of space. The results support that weak ordinal information without quantitative magnitude encoded in the long-term memory can activate spatial representation in a comparison task. PMID:27092100
Lessons on the Northwest Ordinance.
ERIC Educational Resources Information Center
Patrick, John J.
The purpose of this packet of six lessons is to make it easier for teachers to include substantial instruction about the Northwest Ordinance in their secondary school courses. Each lesson includes a lesson plan for teachers and a lesson for students to study. The lessons are concise and can be completed in one or two class meetings. Each lesson…
TACO3D. 3-D Finite Element Heat Transfer Code
Mason, W.E.
1992-03-04
TACO3D is a three-dimensional, finite-element program for heat transfer analysis. An extension of the two-dimensional TACO program, it can perform linear and nonlinear analyses and can be used to solve either transient or steady-state problems. The program accepts time-dependent or temperature-dependent material properties, and materials may be isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions and loadings are available including temperature, flux, convection, and radiation boundary conditions and internal heat generation. Additional specialized features treat enclosure radiation, bulk nodes, and master/slave internal surface conditions (e.g., contact resistance). Data input via a free-field format is provided. A user subprogram feature allows for any type of functional representation of any independent variable. A profile (bandwidth) minimization option is available. The code is limited to implicit time integration for transient solutions. TACO3D has no general mesh generation capability. Rows of evenly-spaced nodes and rows of sequential elements may be generated, but the program relies on separate mesh generators for complex zoning. TACO3D does not have the ability to calculate view factors internally. Graphical representation of data in the form of time history and spatial plots is provided through links to the POSTACO and GRAPE postprocessor codes.
3D toroidal physics: Testing the boundaries of symmetry breaking
Spong, Donald A.
2015-05-15
Toroidal symmetry is an important concept for plasma confinement; it allows the existence of nested flux surface MHD equilibria and conserved invariants for particle motion. However, perfect symmetry is unachievable in realistic toroidal plasma devices. For example, tokamaks have toroidal ripple due to discrete field coils, optimized stellarators do not achieve exact quasi-symmetry, the plasma itself continually seeks lower energy states through helical 3D deformations, and reactors will likely have non-uniform distributions of ferritic steel near the plasma. Also, some level of designed-in 3D magnetic field structure is now anticipated for most concepts in order to provide the plasma control needed for a stable, steady-state fusion reactor. Such planned 3D field structures can take many forms, ranging from tokamaks with weak 3D edge localized mode suppression fields to stellarators with more dominant 3D field structures. This motivates the development of physics models that are applicable across the full range of 3D devices. Ultimately, the questions of how much symmetry breaking can be tolerated and how to optimize its design must be addressed for all fusion concepts. A closely coupled program of simulation, experimental validation, and design optimization is required to determine what forms and amplitudes of 3D shaping and symmetry breaking will be compatible with the requirements of future fusion reactors.
3D toroidal physics: Testing the boundaries of symmetry breakinga)
NASA Astrophysics Data System (ADS)
Spong, Donald A.
2015-05-01
Toroidal symmetry is an important concept for plasma confinement; it allows the existence of nested flux surface MHD equilibria and conserved invariants for particle motion. However, perfect symmetry is unachievable in realistic toroidal plasma devices. For example, tokamaks have toroidal ripple due to discrete field coils, optimized stellarators do not achieve exact quasi-symmetry, the plasma itself continually seeks lower energy states through helical 3D deformations, and reactors will likely have non-uniform distributions of ferritic steel near the plasma. Also, some level of designed-in 3D magnetic field structure is now anticipated for most concepts in order to provide the plasma control needed for a stable, steady-state fusion reactor. Such planned 3D field structures can take many forms, ranging from tokamaks with weak 3D edge localized mode suppression fields to stellarators with more dominant 3D field structures. This motivates the development of physics models that are applicable across the full range of 3D devices. Ultimately, the questions of how much symmetry breaking can be tolerated and how to optimize its design must be addressed for all fusion concepts. A closely coupled program of simulation, experimental validation, and design optimization is required to determine what forms and amplitudes of 3D shaping and symmetry breaking will be compatible with the requirements of future fusion reactors.
Cylindrical 3D video display observable from all directions
NASA Astrophysics Data System (ADS)
Endo, Tomohiro; Kajiki, Yoshihiro; Honda, Toshio; Sato, Makoto
2000-05-01
We propose a 3D video displaying technique that multiple viewers can observe 3D images from 360 degrees of arc horizontally without 3D glasses. This technique uses a cylindrical parallax barrier and 1D light source array. We have developed an experimental display using this technique and have demonstrated 3D images observable form 360 degrees of arc horizontally without 3D glasses. Since this technique is based on the parallax panoramagram, the parallax number and resolution are limited by the diffraction at the parallax barrier. To avoid these limits, we improved the technique by revolving the parallax barrier. We have been developing a new experimental display using this improved technique. The display is capable of displaying cylindrical 3D video images within the diameter of 100 mm and the height of 128 mm. Images are described with the resolution of 1254 pixels circularly and 128 pixels vertically, and refreshed at 30Hz. Each pixel has the viewing angle of 60 degrees and that is divided into 70 views, therefore the angular parallax interval of each pixel is less than 1 degree. In such a case, observers may barely perceive parallax discretely. The pixels are arranged on a cylinder surface, therefore produced 3D images can be observed from all directions.
Social Host Ordinances and Policies. Prevention Update
ERIC Educational Resources Information Center
Higher Education Center for Alcohol, Drug Abuse, and Violence Prevention, 2011
2011-01-01
Social host liability laws (also known as teen party ordinances, loud or unruly gathering ordinances, or response costs ordinances) target the location in which underage drinking takes place. Social host liability laws hold noncommercial individuals responsible for underage drinking events on property they own, lease, or otherwise control. They…
Forensic 3D scene reconstruction
NASA Astrophysics Data System (ADS)
Little, Charles Q.; Small, Daniel E.; Peters, Ralph R.; Rigdon, J. B.
2000-05-01
Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a fieldable prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.
3D Printable Graphene Composite.
Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong
2015-07-08
In human being's history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today's personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite's linear thermal coefficient is below 75 ppm·°C(-1) from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.
Forensic 3D Scene Reconstruction
LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.
1999-10-12
Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.
NASA Technical Reports Server (NTRS)
Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.
2013-01-01
Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.
3D light scanning macrography.
Huber, D; Keller, M; Robert, D
2001-08-01
The technique of 3D light scanning macrography permits the non-invasive surface scanning of small specimens at magnifications up to 200x. Obviating both the problem of limited depth of field inherent to conventional close-up macrophotography and the metallic coating required by scanning electron microscopy, 3D light scanning macrography provides three-dimensional digital images of intact specimens without the loss of colour, texture and transparency information. This newly developed technique offers a versatile, portable and cost-efficient method for the non-invasive digital and photographic documentation of small objects. Computer controlled device operation and digital image acquisition facilitate fast and accurate quantitative morphometric investigations, and the technique offers a broad field of research and educational applications in biological, medical and materials sciences. PMID:11489078
[Real time 3D echocardiography
NASA Technical Reports Server (NTRS)
Bauer, F.; Shiota, T.; Thomas, J. D.
2001-01-01
Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.
[Real time 3D echocardiography].
Bauer, F; Shiota, T; Thomas, J D
2001-07-01
Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients. PMID:11494630
DYNA3D. Explicit 3-d Hydrodynamic FEM Program
Whirley, R.G.; Englemann, B.E. )
1993-11-30
DYNA3D is an explicit, three-dimensional, finite element program for analyzing the large deformation dynamic response of inelastic solids and structures. DYNA3D contains 30 material models and 10 equations of state (EOS) to cover a wide range of material behavior. The material models implemented are: elastic, orthotropic elastic, kinematic/isotropic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, Blatz-Ko rubber, high explosive burn, hydrodynamic without deviatoric stresses, elastoplastic hydrodynamic, temperature-dependent elastoplastic, isotropic elastoplastic, isotropic elastoplastic with failure, soil and crushable foam with failure, Johnson/Cook plasticity model, pseudo TENSOR geological model, elastoplastic with fracture, power law isotropic plasticity, strain rate dependent plasticity, rigid, thermal orthotropic, composite damage model, thermal orthotropic with 12 curves, piecewise linear isotropic plasticity, inviscid two invariant geologic cap, orthotropic crushable model, Moonsy-Rivlin rubber, resultant plasticity, closed form update shell plasticity, and Frazer-Nash rubber model. The hydrodynamic material models determine only the deviatoric stresses. Pressure is determined by one of 10 equations of state including linear polynomial, JWL high explosive, Sack Tuesday high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, tabulated, and TENSOR pore collapse. DYNA3D generates three binary output databases. One contains information for complete states at infrequent intervals; 50 to 100 states is typical. The second contains information for a subset of nodes and elements at frequent intervals; 1,000 to 10,000 states is typical. The last contains interface data for contact surfaces.
GPU-Accelerated Denoising in 3D (GD3D)
2013-10-01
The raw computational power GPU Accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. This software addresses two facets of this promising application: what tuning is necessary to achieve optimal performance on a modern GPU? And what parameters yield the best denoising results in practice? To answer the first question, the software performs an autotuning step to empirically determine optimal memory blocking on the GPU. To answer themore » second, it performs a sweep of algorithm parameters to determine the combination that best reduces the mean squared error relative to a noiseless reference image.« less
A non-conforming 3D spherical harmonic transport solver
Van Criekingen, S.
2006-07-01
A new 3D transport solver for the time-independent Boltzmann transport equation has been developed. This solver is based on the second-order even-parity form of the transport equation. The angular discretization is performed through the expansion of the angular neutron flux in spherical harmonics (PN method). The novelty of this solver is the use of non-conforming finite elements for the spatial discretization. Such elements lead to a discontinuous flux approximation. This interface continuity requirement relaxation property is shared with mixed-dual formulations such as the ones based on Raviart-Thomas finite elements. Encouraging numerical results are presented. (authors)
Numerical simulation of vortex breakdown via 3-D Euler equations
NASA Astrophysics Data System (ADS)
Le, T. H.; Mege, P.; Morchoisne, Y.
1990-06-01
The long term goal is the modeling of vortex breakdown that occurs in some aerodynamic configurations at high angle of attack, (i.e., fighters with highly swept delta wings or missiles). A numerical simulation was made based on solving the 3-D Euler equations for an usteady incompressible flow. Preliminary results were obtained using a pressure-velocity formulation with periodic boundary conditions, the Euler equations being discretized by 2nd order finite difference schemes. The continuation to this work by implementing more realistic boundary conditions and 4th order finite difference discretization schemes are presented.
NASA Astrophysics Data System (ADS)
Kent, G. M.; Harding, A. J.; Babcock, J. M.; Orcutt, J. A.; Bazin, S.; Singh, S.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J.
2002-12-01
Multichannel seismic (MCS) images of crustal magma chambers are ideal targets for advanced visualization techniques. In the mid-ocean ridge environment, reflections originating at the melt-lens are well separated from other reflection boundaries, such as the seafloor, layer 2A and Moho, which enables the effective use of transparency filters. 3-D visualization of seismic reflectivity falls into two broad categories: volume and surface rendering. Volumetric-based visualization is an extremely powerful approach for the rapid exploration of very dense 3-D datasets. These 3-D datasets are divided into volume elements or voxels, which are individually color coded depending on the assigned datum value; the user can define an opacity filter to reject plotting certain voxels. This transparency allows the user to peer into the data volume, enabling an easy identification of patterns or relationships that might have geologic merit. Multiple image volumes can be co-registered to look at correlations between two different data types (e.g., amplitude variation with offsets studies), in a manner analogous to draping attributes onto a surface. In contrast, surface visualization of seismic reflectivity usually involves producing "fence" diagrams of 2-D seismic profiles that are complemented with seafloor topography, along with point class data, draped lines and vectors (e.g. fault scarps, earthquake locations and plate-motions). The overlying seafloor can be made partially transparent or see-through, enabling 3-D correlations between seafloor structure and seismic reflectivity. Exploration of 3-D datasets requires additional thought when constructing and manipulating these complex objects. As numbers of visual objects grow in a particular scene, there is a tendency to mask overlapping objects; this clutter can be managed through the effective use of total or partial transparency (i.e., alpha-channel). In this way, the co-variation between different datasets can be investigated
Inferring evolutionary trees from ordinal data
Kearney, P.E.; Hayward, R.B.; Meijer, H.
1997-06-01
In this paper we present four results on the inference of evolutionary trees from ordinal information. An evolutionary tree T, or phylogeny, is an ordinal representation of a distance matrix , for all species a, b, c and d under consideration. In particular, we show that (1) Ordinal representations of distance matrices can be found in O(n{sup 2}log{sup 2} n) time where n is the number of species. Ordinal representations are shown to be unique, when they exist. (3) Determining if there is an ordinal representation for an incomplete distance matrix, a situation which arises in evolutionary studies, is NP-complete. (3) Finding a phylogeny that best fits a distance matrix containing ordinal errors is NP-complete. (4) Under reasonable conditions, a weighted ordinal representation of a distance matrix can be obtained in polynomial time.
Interactive 3D Mars Visualization
NASA Technical Reports Server (NTRS)
Powell, Mark W.
2012-01-01
The Interactive 3D Mars Visualization system provides high-performance, immersive visualization of satellite and surface vehicle imagery of Mars. The software can be used in mission operations to provide the most accurate position information for the Mars rovers to date. When integrated into the mission data pipeline, this system allows mission planners to view the location of the rover on Mars to 0.01-meter accuracy with respect to satellite imagery, with dynamic updates to incorporate the latest position information. Given this information so early in the planning process, rover drivers are able to plan more accurate drive activities for the rover than ever before, increasing the execution of science activities significantly. Scientifically, this 3D mapping information puts all of the science analyses to date into geologic context on a daily basis instead of weeks or months, as was the norm prior to this contribution. This allows the science planners to judge the efficacy of their previously executed science observations much more efficiently, and achieve greater science return as a result. The Interactive 3D Mars surface view is a Mars terrain browsing software interface that encompasses the entire region of exploration for a Mars surface exploration mission. The view is interactive, allowing the user to pan in any direction by clicking and dragging, or to zoom in or out by scrolling the mouse or touchpad. This set currently includes tools for selecting a point of interest, and a ruler tool for displaying the distance between and positions of two points of interest. The mapping information can be harvested and shared through ubiquitous online mapping tools like Google Mars, NASA WorldWind, and Worldwide Telescope.
NASA Technical Reports Server (NTRS)
2004-01-01
This 3-D cylindrical-perspective mosaic taken by the navigation camera on the Mars Exploration Rover Spirit on sol 82 shows the view south of the large crater dubbed 'Bonneville.' The rover will travel toward the Columbia Hills, seen here at the upper left. The rock dubbed 'Mazatzal' and the hole the rover drilled in to it can be seen at the lower left. The rover's position is referred to as 'Site 22, Position 32.' This image was geometrically corrected to make the horizon appear flat.
NASA Astrophysics Data System (ADS)
Manos, Harry
2016-03-01
Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the TPT theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity well tailored to specific class lessons. Most of the supplies are readily available in the home or at school: rubbing alcohol, a rag, two colors of spray paint, art brushes, and masking tape. The cost of these supplies, if you don't have them, is less than 20.
Love, Lonnie
2015-01-09
ORNL's newly printed 3D Shelby Cobra was showcased at the 2015 NAIAS in Detroit. This "laboratory on wheels" uses the Shelby Cobra design, celebrating the 50th anniversary of this model and honoring the first vehicle to be voted a national monument. The Shelby was printed at the Department of Energy’s Manufacturing Demonstration Facility at ORNL using the BAAM (Big Area Additive Manufacturing) machine and is intended as a “plug-n-play” laboratory on wheels. The Shelby will allow research and development of integrated components to be tested and enhanced in real time, improving the use of sustainable, digital manufacturing solutions in the automotive industry.
Positional Awareness Map 3D (PAM3D)
NASA Technical Reports Server (NTRS)
Hoffman, Monica; Allen, Earl L.; Yount, John W.; Norcross, April Louise
2012-01-01
The Western Aeronautical Test Range of the National Aeronautics and Space Administration s Dryden Flight Research Center needed to address the aging software and hardware of its current situational awareness display application, the Global Real-Time Interactive Map (GRIM). GRIM was initially developed in the late 1980s and executes on older PC architectures using a Linux operating system that is no longer supported. Additionally, the software is difficult to maintain due to its complexity and loss of developer knowledge. It was decided that a replacement application must be developed or acquired in the near future. The replacement must provide the functionality of the original system, the ability to monitor test flight vehicles in real-time, and add improvements such as high resolution imagery and true 3-dimensional capability. This paper will discuss the process of determining the best approach to replace GRIM, and the functionality and capabilities of the first release of the Positional Awareness Map 3D.
3D acoustic atmospheric tomography
NASA Astrophysics Data System (ADS)
Rogers, Kevin; Finn, Anthony
2014-10-01
This paper presents a method for tomographically reconstructing spatially varying 3D atmospheric temperature profiles and wind velocity fields based. Measurements of the acoustic signature measured onboard a small Unmanned Aerial Vehicle (UAV) are compared to ground-based observations of the same signals. The frequency-shifted signal variations are then used to estimate the acoustic propagation delay between the UAV and the ground microphones, which are also affected by atmospheric temperature and wind speed vectors along each sound ray path. The wind and temperature profiles are modelled as the weighted sum of Radial Basis Functions (RBFs), which also allow local meteorological measurements made at the UAV and ground receivers to supplement any acoustic observations. Tomography is used to provide a full 3D reconstruction/visualisation of the observed atmosphere. The technique offers observational mobility under direct user control and the capacity to monitor hazardous atmospheric environments, otherwise not justifiable on the basis of cost or risk. This paper summarises the tomographic technique and reports on the results of simulations and initial field trials. The technique has practical applications for atmospheric research, sound propagation studies, boundary layer meteorology, air pollution measurements, analysis of wind shear, and wind farm surveys.
NASA Astrophysics Data System (ADS)
Laubenstein, John; Cockream, Kandi
2009-05-01
3D spacetime was developed by the IWPD Scale Metrics (SM) team using a coordinate system that translates n dimensions to n-1. 4-vectors are expressed in 3D along with a scaling factor representing time. Time is not orthogonal to the three spatial dimensions, but rather in alignment with an object's axis-of-motion. We have defined this effect as the object's ``orientation'' (X). The SM orientation (X) is equivalent to the orientation of the 4-velocity vector positioned tangent to its worldline, where X-1=θ+1 and θ is the angle of the 4-vector relative to the axis-of -motion. Both 4-vectors and SM appear to represent valid conceptualizations of the relationship between space and time. Why entertain SM? Scale Metrics gravity is quantized and may suggest a path for the full unification of gravitation with quantum theory. SM has been tested against current observation and is in agreement with the age of the universe, suggests a physical relationship between dark energy and dark matter, is in agreement with the accelerating expansion rate of the universe, contributes to the understanding of the fine-structure constant and provides a physical explanation of relativistic effects.
Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C
2013-06-12
The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.
3D medical thermography device
NASA Astrophysics Data System (ADS)
Moghadam, Peyman
2015-05-01
In this paper, a novel handheld 3D medical thermography system is introduced. The proposed system consists of a thermal-infrared camera, a color camera and a depth camera rigidly attached in close proximity and mounted on an ergonomic handle. As a practitioner holding the device smoothly moves it around the human body parts, the proposed system generates and builds up a precise 3D thermogram model by incorporating information from each new measurement in real-time. The data is acquired in motion, thus it provides multiple points of view. When processed, these multiple points of view are adaptively combined by taking into account the reliability of each individual measurement which can vary due to a variety of factors such as angle of incidence, distance between the device and the subject and environmental sensor data or other factors influencing a confidence of the thermal-infrared data when captured. Finally, several case studies are presented to support the usability and performance of the proposed system.
Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C
2013-06-12
The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097
3D Printable Graphene Composite
Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong
2015-01-01
In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C−1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process. PMID:26153673
3D Printable Graphene Composite
NASA Astrophysics Data System (ADS)
Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong
2015-07-01
In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C-1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.
Larry Lawrence; Bruce Miller
2004-09-01
The Lott Ranch 3D seismic prospect located in Garza County, Texas is a project initiated in September of 1991 by the J.M. Huber Corp., a petroleum exploration and production company. By today's standards the 126 square mile project does not seem monumental, however at the time it was conceived it was the most intensive land 3D project ever attempted. Acquisition began in September of 1991 utilizing GEO-SEISMIC, INC., a seismic data contractor. The field parameters were selected by J.M. Huber, and were of a radical design. The recording instruments used were GeoCor IV amplifiers designed by Geosystems Inc., which record the data in signed bit format. It would not have been practical, if not impossible, to have processed the entire raw volume with the tools available at that time. The end result was a dataset that was thought to have little utility due to difficulties in processing the field data. In 1997, Yates Energy Corp. located in Roswell, New Mexico, formed a partnership to further develop the project. Through discussions and meetings with Pinnacle Seismic, it was determined that the original Lott Ranch 3D volume could be vastly improved upon reprocessing. Pinnacle Seismic had shown the viability of improving field-summed signed bit data on smaller 2D and 3D projects. Yates contracted Pinnacle Seismic Ltd. to perform the reprocessing. This project was initiated with high resolution being a priority. Much of the potential resolution was lost through the initial summing of the field data. Modern computers that are now being utilized have tremendous speed and storage capacities that were cost prohibitive when this data was initially processed. Software updates and capabilities offer a variety of quality control and statics resolution, which are pertinent to the Lott Ranch project. The reprocessing effort was very successful. The resulting processed data-set was then interpreted using modern PC-based interpretation and mapping software. Production data, log data
Optimized 3D Ultrashort Echo Time Pulmonary MRI
Johnson, Kevin M.; Fain, Sean B.; Schiebler, Mark L.; Nagle, Scott
2012-01-01
Purpose To optimize 3D radial ultrashort echo time MRI for high resolution whole-lung imaging. Methods 3D radial ultrashort echo time was implemented on a 3T scanner to investigate the effects of: (1) limited field-of-view excitation, (2) variable density readouts, and (3) radial oversampling. Improvements in noise performance and spatial resolution were assessed through simulation and phantom studies. Their effects on lung and airway visualization in five healthy male human subjects (mean age 32 years) were compared qualitatively through blinded ordinal scoring by two cardiothoracic radiologists using a nonparametric Friedman test (P < 0.05). Relative signal difference between endobronchial air and adjacent lung tissue, normalized to nearby vessel, was used as a surrogate for lung tissue signal. Quantitative measures were compared using the paired Student's t-test (P < 0.05). Finally, clinical feasibility was investigated in a patient with interstitial fibrosis. Results Simulation and phantom studies showed up to 67% improvement in SNR and reduced blurring for short T2* species using all three optimizations. In vivo images showed decreased artifacts and improved lung tissue and airway visualization both qualitatively and quantitatively. Conclusion The use of limited field-of-view excitation, variable readout gradients, and radial oversampling significantly improve the technical quality of 3D radial ultrashort echo time lung images. PMID:23213020
3D Printing of Graphene Aerogels.
Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong
2016-04-01
3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction.
3D Printing of Graphene Aerogels.
Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong
2016-04-01
3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction. PMID:26861680
Sinclair, Michael B
2012-01-05
ShowMe3D is a data visualization graphical user interface specifically designed for use with hyperspectral image obtained from the Hyperspectral Confocal Microscope. The program allows the user to select and display any single image from a three dimensional hyperspectral image stack. By moving a slider control, the user can easily move between images of the stack. The user can zoom into any region of the image. The user can select any pixel or region from the displayed image and display the fluorescence spectrum associated with that pixel or region. The user can define up to 3 spectral filters to apply to the hyperspectral image and view the image as it would appear from a filter-based confocal microscope. The user can also obtain statistics such as intensity average and variance from selected regions.
3D Elastic Wavefield Tomography
NASA Astrophysics Data System (ADS)
Guasch, L.; Warner, M.; Stekl, I.; Umpleby, A.; Shah, N.
2010-12-01
Wavefield tomography, or waveform inversion, aims to extract the maximum information from seismic data by matching trace by trace the response of the solid earth to seismic waves using numerical modelling tools. Its first formulation dates from the early 80's, when Albert Tarantola developed a solid theoretical basis that is still used today with little change. Due to computational limitations, the application of the method to 3D problems has been unaffordable until a few years ago, and then only under the acoustic approximation. Although acoustic wavefield tomography is widely used, a complete solution of the seismic inversion problem requires that we account properly for the physics of wave propagation, and so must include elastic effects. We have developed a 3D tomographic wavefield inversion code that incorporates the full elastic wave equation. The bottle neck of the different implementations is the forward modelling algorithm that generates the synthetic data to be compared with the field seismograms as well as the backpropagation of the residuals needed to form the direction update of the model parameters. Furthermore, one or two extra modelling runs are needed in order to calculate the step-length. Our approach uses a FD scheme explicit time-stepping by finite differences that are 4th order in space and 2nd order in time, which is a 3D version of the one developed by Jean Virieux in 1986. We chose the time domain because an explicit time scheme is much less demanding in terms of memory than its frequency domain analogue, although the discussion of wich domain is more efficient still remains open. We calculate the parameter gradients for Vp and Vs by correlating the normal and shear stress wavefields respectively. A straightforward application would lead to the storage of the wavefield at all grid points at each time-step. We tackled this problem using two different approaches. The first one makes better use of resources for small models of dimension equal
Conducting Polymer 3D Microelectrodes
Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi; Castillo-León, Jaime; Emnéus, Jenny; Svendsen, Winnie E.
2010-01-01
Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements. PMID:22163508
2012-01-05
ShowMe3D is a data visualization graphical user interface specifically designed for use with hyperspectral image obtained from the Hyperspectral Confocal Microscope. The program allows the user to select and display any single image from a three dimensional hyperspectral image stack. By moving a slider control, the user can easily move between images of the stack. The user can zoom into any region of the image. The user can select any pixel or region from themore » displayed image and display the fluorescence spectrum associated with that pixel or region. The user can define up to 3 spectral filters to apply to the hyperspectral image and view the image as it would appear from a filter-based confocal microscope. The user can also obtain statistics such as intensity average and variance from selected regions.« less
NASA Astrophysics Data System (ADS)
Dzhalandinov, A.; Tsofin, V.; Kochkin, V.; Panferov, P.; Timofeev, A.; Reshetnikov, A.; Makhotin, D.; Erak, D.; Voloschenko, A.
2016-02-01
Usually the synthesis of two-dimensional and one-dimensional discrete ordinate calculations is used to evaluate neutron fluence on VVER-1000 reactor pressure vessel (RPV) for prognosis of radiation embrittlement. But there are some cases when this approach is not applicable. For example the latest projects of VVER-1000 have upgraded surveillance program. Containers with surveillance specimens are located on the inner surface of RPV with fast neutron flux maximum. Therefore, the synthesis approach is not suitable enough for calculation of local disturbance of neutron field in RPV inner surface behind the surveillance specimens because of their complicated and heterogeneous structure. In some cases the VVER-1000 core loading consists of fuel assemblies with different fuel height and the applicability of synthesis approach is also ambiguous for these fuel cycles. Also, the synthesis approach is not enough correct for the neutron fluence estimation at the RPV area above core top. Because of these reasons only the 3D neutron transport codes seem to be satisfactory for calculation of neutron fluence on the VVER-1000 RPV. The direct 3D calculations are also recommended by modern regulations.
3D toroidal physics: testing the boundaries of symmetry breaking
NASA Astrophysics Data System (ADS)
Spong, Don
2014-10-01
Toroidal symmetry is an important concept for plasma confinement; it allows the existence of nested flux surface MHD equilibria and conserved invariants for particle motion. However, perfect symmetry is unachievable in realistic toroidal plasma devices. For example, tokamaks have toroidal ripple due to discrete field coils, optimized stellarators do not achieve exact quasi-symmetry, the plasma itself continually seeks lower energy states through helical 3D deformations, and reactors will likely have non-uniform distributions of ferritic steel near the plasma. Also, some level of designed-in 3D magnetic field structure is now anticipated for most concepts in order to lead to a stable, steady-state fusion reactor. Such planned 3D field structures can take many forms, ranging from tokamaks with weak 3D ELM-suppression fields to stellarators with more dominant 3D field structures. There is considerable interest in the development of unified physics models for the full range of 3D effects. Ultimately, the questions of how much symmetry breaking can be tolerated and how to optimize its design must be addressed for all fusion concepts. Fortunately, significant progress is underway in theory, computation and plasma diagnostics on many issues such as magnetic surface quality, plasma screening vs. amplification of 3D perturbations, 3D transport, influence on edge pedestal structures, MHD stability effects, modification of fast ion-driven instabilities, prediction of energetic particle heat loads on plasma-facing materials, effects of 3D fields on turbulence, and magnetic coil design. A closely coupled program of simulation, experimental validation, and design optimization is required to determine what forms and amplitudes of 3D shaping and symmetry breaking will be compatible with future fusion reactors. The development of models to address 3D physics and progress in these areas will be described. This work is supported both by the US Department of Energy under Contract DE
3D multiplexed immunoplasmonics microscopy
NASA Astrophysics Data System (ADS)
Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel
2016-07-01
Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed
3D multiplexed immunoplasmonics microscopy.
Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel
2016-07-21
Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K(+) channel subunit KV1.1) on human cancer CD44(+) EGFR(+) KV1.1(+) MDA-MB-231 cells and reference CD44(-) EGFR(-) KV1.1(+) 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third
NIF Ignition Target 3D Point Design
Jones, O; Marinak, M; Milovich, J; Callahan, D
2008-11-05
We have developed an input file for running 3D NIF hohlraums that is optimized such that it can be run in 1-2 days on parallel computers. We have incorporated increasing levels of automation into the 3D input file: (1) Configuration controlled input files; (2) Common file for 2D and 3D, different types of capsules (symcap, etc.); and (3) Can obtain target dimensions, laser pulse, and diagnostics settings automatically from NIF Campaign Management Tool. Using 3D Hydra calculations to investigate different problems: (1) Intrinsic 3D asymmetry; (2) Tolerance to nonideal 3D effects (e.g. laser power balance, pointing errors); and (3) Synthetic diagnostics.
3D computer data capture and imaging applied to the face and jaws.
Spencer, R; Hathaway, R; Speculand, B
1996-02-01
There have been few attempts in the past at 3D computer modelling of facial deformity because of the difficulties with generating accurate three-dimensional data and subsequent image regeneration and manipulation. We report the application of computer aided engineering techniques to the study of jaw deformity. The construction of a 3D image of the mandible using a Ferranti co-ordinate measuring machine for data capture and the 'DUCT5' surface modelling programme for image regeneration is described. The potential application of this work will be discussed. PMID:8645664
Measurements of 3D slip velocities and plasma column lengths of a gliding arc discharge
Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas; Aldén, Marcus; Li, Zhongshan E-mail: alpers@ma.tum.de; Moseev, Dmitry; Kusano, Yukihiro; Salewski, Mirko; Alpers, Andreas E-mail: alpers@ma.tum.de; Gritzmann, Peter; Schwenk, Martin
2015-01-26
A non-thermal gliding arc discharge was generated at atmospheric pressure in an air flow. The dynamics of the plasma column and tracer particles were recorded using two synchronized high-speed cameras. Whereas the data analysis for such systems has previously been performed in 2D (analyzing the single camera image), we provide here a 3D data analysis that includes 3D reconstructions of the plasma column and 3D particle tracking velocimetry based on discrete tomography methods. The 3D analysis, in particular, the determination of the 3D slip velocity between the plasma column and the gas flow, gives more realistic insight into the convection cooling process. Additionally, with the determination of the 3D slip velocity and the 3D length of the plasma column, we give more accurate estimates for the drag force, the electric field strength, the power per unit length, and the radius of the conducting zone of the plasma column.
NASA Astrophysics Data System (ADS)
Hermanns, Maria
The Kitaev honeycomb model has become one of the archetypal spin models exhibiting topological phases of matter, where the magnetic moments fractionalize into Majorana fermions interacting with a Z2 gauge field. In this talk, we discuss generalizations of this model to three-dimensional lattice structures. Our main focus is the metallic state that the emergent Majorana fermions form. In particular, we discuss the relation of the nature of this Majorana metal to the details of the underlying lattice structure. Besides (almost) conventional metals with a Majorana Fermi surface, one also finds various realizations of Dirac semi-metals, where the gapless modes form Fermi lines or even Weyl nodes. We introduce a general classification of these gapless quantum spin liquids using projective symmetry analysis. Furthermore, we briefly outline why these Majorana metals in 3D Kitaev systems provide an even richer variety of Dirac and Weyl phases than possible for electronic matter and comment on possible experimental signatures. Work done in collaboration with Kevin O'Brien and Simon Trebst.
Locomotive wheel 3D reconstruction
NASA Astrophysics Data System (ADS)
Guan, Xin; Luo, Zhisheng; Gao, Xiaorong; Wu, Jianle
2010-08-01
In the article, a system, which is used to reconstruct locomotive wheels, is described, helping workers detect the condition of a wheel through a direct view. The system consists of a line laser, a 2D camera, and a computer. We use 2D camera to capture the line-laser light reflected by the object, a wheel, and then compute the final coordinates of the structured light. Finally, using Matlab programming language, we transform the coordinate of points to a smooth surface and illustrate the 3D view of the wheel. The article also proposes the system structure, processing steps and methods, and sets up an experimental platform to verify the design proposal. We verify the feasibility of the whole process, and analyze the results comparing to standard date. The test results show that this system can work well, and has a high accuracy on the reconstruction. And because there is still no such application working in railway industries, so that it has practical value in railway inspection system.
NASA Astrophysics Data System (ADS)
Mahjoubfar, A.; Goda, K.; Wang, C.; Fard, A.; Adam, J.; Gossett, D. R.; Ayazi, A.; Sollier, E.; Malik, O.; Chen, E.; Liu, Y.; Brown, R.; Sarkhosh, N.; Di Carlo, D.; Jalali, B.
2013-03-01
Laser scanners are essential for scientific research, manufacturing, defense, and medical practice. Unfortunately, often times the speed of conventional laser scanners (e.g., galvanometric mirrors and acousto-optic deflectors) falls short for many applications, resulting in motion blur and failure to capture fast transient information. Here, we present a novel type of laser scanner that offers roughly three orders of magnitude higher scan rates than conventional methods. Our laser scanner, which we refer to as the hybrid dispersion laser scanner, performs inertia-free laser scanning by dispersing a train of broadband pulses both temporally and spatially. More specifically, each broadband pulse is temporally processed by time stretch dispersive Fourier transform and further dispersed into space by one or more diffractive elements such as prisms and gratings. As a proof-of-principle demonstration, we perform 1D line scans at a record high scan rate of 91 MHz and 2D raster scans and 3D volumetric scans at an unprecedented scan rate of 105 kHz. The method holds promise for a broad range of scientific, industrial, and biomedical applications. To show the utility of our method, we demonstrate imaging, nanometer-resolved surface vibrometry, and high-precision flow cytometry with real-time throughput that conventional laser scanners cannot offer due to their low scan rates.
3D multiplexed immunoplasmonics microscopy
NASA Astrophysics Data System (ADS)
Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel
2016-07-01
Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed
Crowdsourcing Based 3d Modeling
NASA Astrophysics Data System (ADS)
Somogyi, A.; Barsi, A.; Molnar, B.; Lovas, T.
2016-06-01
Web-based photo albums that support organizing and viewing the users' images are widely used. These services provide a convenient solution for storing, editing and sharing images. In many cases, the users attach geotags to the images in order to enable using them e.g. in location based applications on social networks. Our paper discusses a procedure that collects open access images from a site frequently visited by tourists. Geotagged pictures showing the image of a sight or tourist attraction are selected and processed in photogrammetric processing software that produces the 3D model of the captured object. For the particular investigation we selected three attractions in Budapest. To assess the geometrical accuracy, we used laser scanner and DSLR as well as smart phone photography to derive reference values to enable verifying the spatial model obtained from the web-album images. The investigation shows how detailed and accurate models could be derived applying photogrammetric processing software, simply by using images of the community, without visiting the site.
Squeezing Interval Change From Ordinal Panel Data: Latent Growth Curves With Ordinal Outcomes
ERIC Educational Resources Information Center
Mehta, Paras D.; Neale, Michael C.; Flay, Brian R.
2004-01-01
A didactic on latent growth curve modeling for ordinal outcomes is presented. The conceptual aspects of modeling growth with ordinal variables and the notion of threshold invariance are illustrated graphically using a hypothetical example. The ordinal growth model is described in terms of 3 nested models: (a) multivariate normality of the…
NASA Technical Reports Server (NTRS)
1997-01-01
Mars Pathfinder's forward rover ramp can be seen successfully unfurled in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This ramp was not used for the deployment of the microrover Sojourner, which occurred at the end of Sol 2. When this image was taken, Sojourner was still latched to one of the lander's petals, waiting for the command sequence that would execute its descent off of the lander's petal.
The image helped Pathfinder scientists determine whether to deploy the rover using the forward or backward ramps and the nature of the first rover traverse. The metallic object at the lower left of the image is the lander's low-gain antenna. The square at the end of the ramp is one of the spacecraft's magnetic targets. Dust that accumulates on the magnetic targets will later be examined by Sojourner's Alpha Proton X-Ray Spectrometer instrument for chemical analysis. At right, a lander petal is visible.
The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.' It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters.
Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.
Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right
3D Printing and Its Urologic Applications
Soliman, Youssef; Feibus, Allison H; Baum, Neil
2015-01-01
3D printing is the development of 3D objects via an additive process in which successive layers of material are applied under computer control. This article discusses 3D printing, with an emphasis on its historical context and its potential use in the field of urology. PMID:26028997
Imaging a Sustainable Future in 3D
NASA Astrophysics Data System (ADS)
Schuhr, W.; Lee, J. D.; Kanngieser, E.
2012-07-01
It is the intention of this paper, to contribute to a sustainable future by providing objective object information based on 3D photography as well as promoting 3D photography not only for scientists, but also for amateurs. Due to the presentation of this article by CIPA Task Group 3 on "3D Photographs in Cultural Heritage", the presented samples are masterpieces of historic as well as of current 3D photography concentrating on cultural heritage. In addition to a report on exemplarily access to international archives of 3D photographs, samples for new 3D photographs taken with modern 3D cameras, as well as by means of a ground based high resolution XLITE staff camera and also 3D photographs taken from a captive balloon and the use of civil drone platforms are dealt with. To advise on optimum suited 3D methodology, as well as to catch new trends in 3D, an updated synoptic overview of the 3D visualization technology, even claiming completeness, has been carried out as a result of a systematic survey. In this respect, e.g., today's lasered crystals might be "early bird" products in 3D, which, due to lack in resolution, contrast and color, remember to the stage of the invention of photography.
3D Printing and Its Urologic Applications.
Soliman, Youssef; Feibus, Allison H; Baum, Neil
2015-01-01
3D printing is the development of 3D objects via an additive process in which successive layers of material are applied under computer control. This article discusses 3D printing, with an emphasis on its historical context and its potential use in the field of urology.
NASA Astrophysics Data System (ADS)
Engle, Rob
2008-02-01
This paper discusses the creative and technical challenges encountered during the production of "Beowulf 3D," director Robert Zemeckis' adaptation of the Old English epic poem and the first film to be simultaneously released in IMAX 3D and digital 3D formats.
Teaching Geography with 3-D Visualization Technology
ERIC Educational Resources Information Center
Anthamatten, Peter; Ziegler, Susy S.
2006-01-01
Technology that helps students view images in three dimensions (3-D) can support a broad range of learning styles. "Geo-Wall systems" are visualization tools that allow scientists, teachers, and students to project stereographic images and view them in 3-D. We developed and presented 3-D visualization exercises in several undergraduate courses.…
Expanding Geometry Understanding with 3D Printing
ERIC Educational Resources Information Center
Cochran, Jill A.; Cochran, Zane; Laney, Kendra; Dean, Mandi
2016-01-01
With the rise of personal desktop 3D printing, a wide spectrum of educational opportunities has become available for educators to leverage this technology in their classrooms. Until recently, the ability to create physical 3D models was well beyond the scope, skill, and budget of many schools. However, since desktop 3D printers have become readily…
3D Elastic Seismic Wave Propagation Code
1998-09-23
E3D is capable of simulating seismic wave propagation in a 3D heterogeneous earth. Seismic waves are initiated by earthquake, explosive, and/or other sources. These waves propagate through a 3D geologic model, and are simulated as synthetic seismograms or other graphical output.
3D Flow Visualization Using Texture Advection
NASA Technical Reports Server (NTRS)
Kao, David; Zhang, Bing; Kim, Kwansik; Pang, Alex; Moran, Pat (Technical Monitor)
2001-01-01
Texture advection is an effective tool for animating and investigating 2D flows. In this paper, we discuss how this technique can be extended to 3D flows. In particular, we examine the use of 3D and 4D textures on 3D synthetic and computational fluid dynamics flow fields.
The Northwest Ordinance. A Special Issue.
ERIC Educational Resources Information Center
Sheehan, Bernard W., Ed.; And Others
1988-01-01
Eight articles discuss different aspects of the Northwest ordinances. W. W. Abbot emphasizes George Washington's enduring, complex, and deep involvement with the west and its land. Robert V. Remini points out the value of the Articles of Confederation by emphasizing that it was the Congress under the Articles that passed the Northwest Ordinance.…
The Northwest Ordinance, 1787: A Bicentennial Handbook.
ERIC Educational Resources Information Center
Taylor, Robert M., Jr., Ed.
The essays and annotations in this publication provide an opportunity for citizens and students to consider not only the history of the Northwest Ordinance but also basic and enduring issues in U.S. political life. The book is divided into three main parts. The first part provides a background to the Ordinance and its passage by the Confederation…
Economic Analysis of a Living Wage Ordinance.
ERIC Educational Resources Information Center
Tolley, George; Bernstein, Peter
A study estimated the costs of the "Chicago Jobs and Living Wage Ordinance" that would require firms that receive assistance from the city of Chicago to pay their workers an hourly wage of at least $7.60. An estimate of the additional labor cost that would result from the proposed Ordinance was calculated. Results of a survey of contractors,…
3-D Perspective Pasadena, California
NASA Technical Reports Server (NTRS)
2000-01-01
This perspective view shows the western part of the city of Pasadena, California, looking north towards the San Gabriel Mountains. Portions of the cities of Altadena and La Canada, Flintridge are also shown. The image was created from three datasets: the Shuttle Radar Topography Mission (SRTM) supplied the elevation data; Landsat data from November 11, 1986 provided the land surface color (not the sky) and U.S. Geological Survey digital aerial photography provides the image detail. The Rose Bowl, surrounded by a golf course, is the circular feature at the bottom center of the image. The Jet Propulsion Laboratory is the cluster of large buildings north of the Rose Bowl at the base of the mountains. A large landfill, Scholl Canyon, is the smooth area in the lower left corner of the scene. This image shows the power of combining data from different sources to create planning tools to study problems that affect large urban areas. In addition to the well-known earthquake hazards, Southern California is affected by a natural cycle of fire and mudflows. Wildfires strip the mountains of vegetation, increasing the hazards from flooding and mudflows for several years afterwards. Data such as shown on this image can be used to predict both how wildfires will spread over the terrain and also how mudflows will be channeled down the canyons. The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency
The Bicentennial of the Northwest Ordinance of 1787.
ERIC Educational Resources Information Center
Patrick, John J.
1987-01-01
Reviews the political history surrounding the development of the Northwest Ordinance of 1787. Includes a shortened and simplified version of the major articles of the Ordinance. Identifies three instructional resources for teaching about the Northwest Ordinance in secondary schools. (JDH)
Case study: Beauty and the Beast 3D: benefits of 3D viewing for 2D to 3D conversion
NASA Astrophysics Data System (ADS)
Handy Turner, Tara
2010-02-01
From the earliest stages of the Beauty and the Beast 3D conversion project, the advantages of accurate desk-side 3D viewing was evident. While designing and testing the 2D to 3D conversion process, the engineering team at Walt Disney Animation Studios proposed a 3D viewing configuration that not only allowed artists to "compose" stereoscopic 3D but also improved efficiency by allowing artists to instantly detect which image features were essential to the stereoscopic appeal of a shot and which features had minimal or even negative impact. At a time when few commercial 3D monitors were available and few software packages provided 3D desk-side output, the team designed their own prototype devices and collaborated with vendors to create a "3D composing" workstation. This paper outlines the display technologies explored, final choices made for Beauty and the Beast 3D, wish-lists for future development and a few rules of thumb for composing compelling 2D to 3D conversions.
Riemke, Richard Allan
2002-09-01
The Reactor Excursion and Leak Analysis Program with 3D capability1 (RELAP5-3D) is a reactor system analysis code that has been developed at the Idaho National Engineering and Environmental Laboratory (INEEL) for the U. S. Department of Energy (DOE). The 3D capability in RELAP5-3D includes 3D hydrodynamics2 and 3D neutron kinetics3,4. Assessment, verification, and validation of the 3D capability in RELAP5-3D is discussed in the literature5,6,7,8,9,10. Additional assessment, verification, and validation of the 3D capability of RELAP5-3D will be presented in other papers in this users seminar. As with any software, user problems occur. User problems usually fall into the categories of input processing failure, code execution failure, restart/renodalization failure, unphysical result, and installation. This presentation will discuss some of the more generic user problems that have been reported on RELAP5-3D as well as their resolution.
3D laptop for defense applications
NASA Astrophysics Data System (ADS)
Edmondson, Richard; Chenault, David
2012-06-01
Polaris Sensor Technologies has developed numerous 3D display systems using a US Army patented approach. These displays have been developed as prototypes for handheld controllers for robotic systems and closed hatch driving, and as part of a TALON robot upgrade for 3D vision, providing depth perception for the operator for improved manipulation and hazard avoidance. In this paper we discuss the prototype rugged 3D laptop computer and its applications to defense missions. The prototype 3D laptop combines full temporal and spatial resolution display with the rugged Amrel laptop computer. The display is viewed through protective passive polarized eyewear, and allows combined 2D and 3D content. Uses include robot tele-operation with live 3D video or synthetically rendered scenery, mission planning and rehearsal, enhanced 3D data interpretation, and simulation.
Wavefront scanning method for minimum traveltime calculations in 3-D
Meng, F.; Liu, H.; Li, Y.
1994-12-31
This paper proposes an efficient way to calculate the shortest travel-time and its correspondent ray-path in three dimension, by using point secondary approximation to depict the wavefront and propagate the travel-time computation along recursively expanding and contracting cubic boxes. Due to its following advantages: (1) the computation order is O(N), where N is the total number of discrete secondary nodes; (2) the memory occupation is relatively small; (3) the algorithm is robust even for high velocity contrast; (4) the minimum travel-time and raypath are computed accurately, this 3-D wavefront scanning raytracing method promises to be real tool for 3-D seismic prestack migration, velocity analysis as well as forward waveform modeling by Maslov asymptotic ray theory.
The IDA Model Outdoor Lighting Ordinance
NASA Astrophysics Data System (ADS)
Crawford, D. L.
2004-05-01
The International Dark-Sky Association has produced a model outdoor lighting ordinance, available for any community that wishes to adopt an ordinance to control outdoor lighting. The goal is to help protect dark skies and/or to minimize the adverse effects of poor outdoor night lighting. This is done in response to a high demand for such a model, one that can offer a uniform content to all communities, hence easier to adopt and easier to enforce. It will allow a national educational effort to be done to show the value of such ordinances in practice. There are currently many ordinances in existence, most of them not very effective. It is hard for designers, manufacturers, and others to cope with such a wide variety, and with non-standard terms and requirements. One of the key elements of such the model ordinance is the use of "lighting zones." The first version (2004.1) is now on the IDA web site, at www.darksky.org. Questions are welcome at any time, address such to ida@darksky.org. We urge all interest in prserving dark skies for astronomy to become active in the issues, including a push for adoptaton of such a model ordinance in their area. We know that viable ordinances do help greatly in preseving dark skies for astronomy, and the good ones now in existence prove this fact.
3-D Technology Approaches for Biological Ecologies
NASA Astrophysics Data System (ADS)
Liu, Liyu; Austin, Robert; U. S-China Physical-Oncology Sciences Alliance (PS-OA) Team
Constructing three dimensional (3-D) landscapes is an inevitable issue in deep study of biological ecologies, because in whatever scales in nature, all of the ecosystems are composed by complex 3-D environments and biological behaviors. Just imagine if a 3-D technology could help complex ecosystems be built easily and mimic in vivo microenvironment realistically with flexible environmental controls, it will be a fantastic and powerful thrust to assist researchers for explorations. For years, we have been utilizing and developing different technologies for constructing 3-D micro landscapes for biophysics studies in in vitro. Here, I will review our past efforts, including probing cancer cell invasiveness with 3-D silicon based Tepuis, constructing 3-D microenvironment for cell invasion and metastasis through polydimethylsiloxane (PDMS) soft lithography, as well as explorations of optimized stenting positions for coronary bifurcation disease with 3-D wax printing and the latest home designed 3-D bio-printer. Although 3-D technologies is currently considered not mature enough for arbitrary 3-D micro-ecological models with easy design and fabrication, I hope through my talk, the audiences will be able to sense its significance and predictable breakthroughs in the near future. This work was supported by the State Key Development Program for Basic Research of China (Grant No. 2013CB837200), the National Natural Science Foundation of China (Grant No. 11474345) and the Beijing Natural Science Foundation (Grant No. 7154221).
Automatic 3D video format detection
NASA Astrophysics Data System (ADS)
Zhang, Tao; Wang, Zhe; Zhai, Jiefu; Doyen, Didier
2011-03-01
Many 3D formats exist and will probably co-exist for a long time even if 3D standards are today under definition. The support for multiple 3D formats will be important for bringing 3D into home. In this paper, we propose a novel and effective method to detect whether a video is a 3D video or not, and to further identify the exact 3D format. First, we present how to detect those 3D formats that encode a pair of stereo images into a single image. The proposed method detects features and establishes correspondences between features in the left and right view images, and applies the statistics from the distribution of the positional differences between corresponding features to detect the existence of a 3D format and to identify the format. Second, we present how to detect the frame sequential 3D format. In the frame sequential 3D format, the feature points are oscillating from frame to frame. Similarly, the proposed method tracks feature points over consecutive frames, computes the positional differences between features, and makes a detection decision based on whether the features are oscillating. Experiments show the effectiveness of our method.
Clement, T.P.; Jones, N.L.
1998-02-01
RT3D (Reactive Transport in 3-Dimensions) is a computer code that solves coupled partial differential equations that describe reactive-flow and transport of multiple mobile and/or immobile species in a three dimensional saturated porous media. RT3D was developed from the single-species transport code, MT3D (DoD-1.5, 1997 version). As with MT3D, RT3D also uses the USGS groundwater flow model MODFLOW for computing spatial and temporal variations in groundwater head distribution. This report presents a set of tutorial problems that are designed to illustrate how RT3D simulations can be performed within the Department of Defense Groundwater Modeling System (GMS). GMS serves as a pre- and post-processing interface for RT3D. GMS can be used to define all the input files needed by RT3D code, and later the code can be launched from within GMS and run as a separate application. Once the RT3D simulation is completed, the solution can be imported to GMS for graphical post-processing. RT3D v1.0 supports several reaction packages that can be used for simulating different types of reactive contaminants. Each of the tutorials, described below, provides training on a different RT3D reaction package. Each reaction package has different input requirements, and the tutorials are designed to describe these differences. Furthermore, the tutorials illustrate the various options available in GMS for graphical post-processing of RT3D results. Users are strongly encouraged to complete the tutorials before attempting to use RT3D and GMS on a routine basis.
Quantitative Reconstructions of 3D Chemical Nanostructures in Nanowires.
Rueda-Fonseca, P; Robin, E; Bellet-Amalric, E; Lopez-Haro, M; Den Hertog, M; Genuist, Y; André, R; Artioli, A; Tatarenko, S; Ferrand, D; Cibert, J
2016-03-01
Energy dispersive X-ray spectrometry is used to extract a quantitative 3D composition profile of heterostructured nanowires. The analysis of hypermaps recorded along a limited number of projections, with a preliminary calibration of the signal associated with each element, is compared to the intensity profiles calculated for a model structure with successive shells of circular, elliptic, or faceted cross sections. This discrete tomographic technique is applied to II-VI nanowires grown by molecular beam epitaxy, incorporating ZnTe and CdTe and their alloys with Mn and Mg, with typical size down to a few nanometers and Mn or Mg content as low as 10%.
3-D HYDRODYNAMIC MODELING IN A GEOSPATIAL FRAMEWORK
Bollinger, J; Alfred Garrett, A; Larry Koffman, L; David Hayes, D
2006-08-24
3-D hydrodynamic models are used by the Savannah River National Laboratory (SRNL) to simulate the transport of thermal and radionuclide discharges in coastal estuary systems. Development of such models requires accurate bathymetry, coastline, and boundary condition data in conjunction with the ability to rapidly discretize model domains and interpolate the required geospatial data onto the domain. To facilitate rapid and accurate hydrodynamic model development, SRNL has developed a pre- and post-processor application in a geospatial framework to automate the creation of models using existing data. This automated capability allows development of very detailed models to maximize exploitation of available surface water radionuclide sample data and thermal imagery.
First 3D view of solar eruptions
NASA Astrophysics Data System (ADS)
2004-07-01
arrival times and impact angles at the Earth," says Dr Thomas Moran of the Catholic University, Washington, USA. In collaboration with Dr Joseph Davila, of NASA’s Goddard Space Flight Center, Greenbelt, USA, Moran has analysed two-dimensional images from the ESA/NASA Solar and Heliospheric Observatory (SOHO) in a new way to yield 3D images. Their technique is able to reveal the complex and distorted magnetic fields that travel with the CME cloud and sometimes interact with Earth's own magnetic field, pouring tremendous amounts of energy into the space near Earth. "These magnetic fields are invisible," Moran explains, "but since the CME gas is electrified, it spirals around the magnetic fields, tracing out their shapes." Therefore, a 3D view of the CME electrified gas (called a plasma) gives scientists valuable information on the structure and behaviour of the magnetic fields powering the CME. The new analysis technique for SOHO data determines the three-dimensional structure of a CME by taking a sequence of three SOHO Large Angle and Spectrometric Coronagraph (LASCO) images through various polarisers, at different angles. Whilst the light emitted by the Sun is not polarised, once it is scattered off electrons in the CME plasma it takes up some polarisation. This means that the electric fields of some of the scattered light are forced to oscillate in certain directions, whereas the electric field in the light emitted by the Sun is free to oscillate in all directions. Moran and Davila knew that light from CME structures closer to the plane of the Sun (as seen on the LASCO images) had to be more polarised than light from structures farther from that plane. Thus, by computing the ratio of polarised to unpolarised light for each CME structure, they could measure its distance from the plane. This provided the missing third dimension to the LASCO images. With this technique, the team has confirmed that the structure of CMEs directed towards Earth is an expanding arcade of
Incremental learning of 3D-DCT compact representations for robust visual tracking.
Li, Xi; Dick, Anthony; Shen, Chunhua; van den Hengel, Anton; Wang, Hanzi
2013-04-01
Visual tracking usually requires an object appearance model that is robust to changing illumination, pose, and other factors encountered in video. Many recent trackers utilize appearance samples in previous frames to form the bases upon which the object appearance model is built. This approach has the following limitations: 1) The bases are data driven, so they can be easily corrupted, and 2) it is difficult to robustly update the bases in challenging situations. In this paper, we construct an appearance model using the 3D discrete cosine transform (3D-DCT). The 3D-DCT is based on a set of cosine basis functions which are determined by the dimensions of the 3D signal and thus independent of the input video data. In addition, the 3D-DCT can generate a compact energy spectrum whose high-frequency coefficients are sparse if the appearance samples are similar. By discarding these high-frequency coefficients, we simultaneously obtain a compact 3D-DCT-based object representation and a signal reconstruction-based similarity measure (reflecting the information loss from signal reconstruction). To efficiently update the object representation, we propose an incremental 3D-DCT algorithm which decomposes the 3D-DCT into successive operations of the 2D discrete cosine transform (2D-DCT) and 1D discrete cosine transform (1D-DCT) on the input video data. As a result, the incremental 3D-DCT algorithm only needs to compute the 2D-DCT for newly added frames as well as the 1D-DCT along the third dimension, which significantly reduces the computational complexity. Based on this incremental 3D-DCT algorithm, we design a discriminative criterion to evaluate the likelihood of a test sample belonging to the foreground object. We then embed the discriminative criterion into a particle filtering framework for object state inference over time. Experimental results demonstrate the effectiveness and robustness of the proposed tracker.
Dimensional accuracy of 3D printed vertebra
NASA Astrophysics Data System (ADS)
Ogden, Kent; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Aslan, Can
2014-03-01
3D printer applications in the biomedical sciences and medical imaging are expanding and will have an increasing impact on the practice of medicine. Orthopedic and reconstructive surgery has been an obvious area for development of 3D printer applications as the segmentation of bony anatomy to generate printable models is relatively straightforward. There are important issues that should be addressed when using 3D printed models for applications that may affect patient care; in particular the dimensional accuracy of the printed parts needs to be high to avoid poor decisions being made prior to surgery or therapeutic procedures. In this work, the dimensional accuracy of 3D printed vertebral bodies derived from CT data for a cadaver spine is compared with direct measurements on the ex-vivo vertebra and with measurements made on the 3D rendered vertebra using commercial 3D image processing software. The vertebra was printed on a consumer grade 3D printer using an additive print process using PLA (polylactic acid) filament. Measurements were made for 15 different anatomic features of the vertebral body, including vertebral body height, endplate width and depth, pedicle height and width, and spinal canal width and depth, among others. It is shown that for the segmentation and printing process used, the results of measurements made on the 3D printed vertebral body are substantially the same as those produced by direct measurement on the vertebra and measurements made on the 3D rendered vertebra.
Stereo 3-D Vision in Teaching Physics
NASA Astrophysics Data System (ADS)
Zabunov, Svetoslav
2012-03-01
Stereo 3-D vision is a technology used to present images on a flat surface (screen, paper, etc.) and at the same time to create the notion of three-dimensional spatial perception of the viewed scene. A great number of physical processes are much better understood when viewed in stereo 3-D vision compared to standard flat 2-D presentation. The current paper describes the modern stereo 3-D technologies that are applicable to various tasks in teaching physics in schools, colleges, and universities. Examples of stereo 3-D simulations developed by the author can be observed on online.
Software for 3D radiotherapy dosimetry. Validation
NASA Astrophysics Data System (ADS)
Kozicki, Marek; Maras, Piotr; Karwowski, Andrzej C.
2014-08-01
The subject of this work is polyGeVero® software (GeVero Co., Poland), which has been developed to fill the requirements of fast calculations of 3D dosimetry data with the emphasis on polymer gel dosimetry for radiotherapy. This software comprises four workspaces that have been prepared for: (i) calculating calibration curves and calibration equations, (ii) storing the calibration characteristics of the 3D dosimeters, (iii) calculating 3D dose distributions in irradiated 3D dosimeters, and (iv) comparing 3D dose distributions obtained from measurements with the aid of 3D dosimeters and calculated with the aid of treatment planning systems (TPSs). The main features and functions of the software are described in this work. Moreover, the core algorithms were validated and the results are presented. The validation was performed using the data of the new PABIGnx polymer gel dosimeter. The polyGeVero® software simplifies and greatly accelerates the calculations of raw 3D dosimetry data. It is an effective tool for fast verification of TPS-generated plans for tumor irradiation when combined with a 3D dosimeter. Consequently, the software may facilitate calculations by the 3D dosimetry community. In this work, the calibration characteristics of the PABIGnx obtained through four calibration methods: multi vial, cross beam, depth dose, and brachytherapy, are discussed as well.
[3D reconstructions in radiotherapy planning].
Schlegel, W
1991-10-01
3D Reconstructions from tomographic images are used in the planning of radiation therapy to study important anatomical structures such as the body surface, target volumes, and organs at risk. The reconstructed anatomical models are used to define the geometry of the radiation beams. In addition, 3D voxel models are used for the calculation of the 3D dose distributions with an accuracy, previously impossible to achieve. Further uses of 3D reconstructions are in the display and evaluation of 3D therapy plans, and in the transfer of treatment planning parameters to the irradiation situation with the help of digitally reconstructed radiographs. 3D tomographic imaging with subsequent 3D reconstruction must be regarded as a completely new basis for the planning of radiation therapy, enabling tumor-tailored radiation therapy of localized target volumes with increased radiation doses and improved sparing of organs at risk. 3D treatment planning is currently being evaluated in clinical trials in connection with the new treatment techniques of conformation radiotherapy. Early experience with 3D treatment planning shows that its clinical importance in radiotherapy is growing, but will only become a standard radiotherapy tool when volumetric CT scanning, reliable and user-friendly treatment planning software, and faster and cheaper PACS-integrated medical work stations are accessible to radiotherapists.
Revisiting the Concept of Level of Detail in 3d City Modelling
NASA Astrophysics Data System (ADS)
Biljecki, F.; Zhao, J.; Stoter, J.; Ledoux, H.
2013-09-01
This review paper discusses the concept of level of detail in 3D city modelling, and is a first step towards a foundation for a standardised definition. As an introduction, a few level of detail specifications, outlooks and approaches are given from the industry. The paper analyses the general uncertainties and shortcomings around the concept of level of detail in 3D city modelling such as ordinality and inconsistencies, and identifies factors that constitute a specific level of detail. The paper proposes a framework for a new consistent LoD definition which would consolidate present and future LoD paradigms, gives an example of an LoD specification, discusses open questions such as the contexts for which 3D city models are used in practice, and gives prospects for a future quantification and sorting of levels of detail.
FastScript3D - A Companion to Java 3D
NASA Technical Reports Server (NTRS)
Koenig, Patti
2005-01-01
FastScript3D is a computer program, written in the Java 3D(TM) programming language, that establishes an alternative language that helps users who lack expertise in Java 3D to use Java 3D for constructing three-dimensional (3D)-appearing graphics. The FastScript3D language provides a set of simple, intuitive, one-line text-string commands for creating, controlling, and animating 3D models. The first word in a string is the name of a command; the rest of the string contains the data arguments for the command. The commands can also be used as an aid to learning Java 3D. Developers can extend the language by adding custom text-string commands. The commands can define new 3D objects or load representations of 3D objects from files in formats compatible with such other software systems as X3D. The text strings can be easily integrated into other languages. FastScript3D facilitates communication between scripting languages [which enable programming of hyper-text markup language (HTML) documents to interact with users] and Java 3D. The FastScript3D language can be extended and customized on both the scripting side and the Java 3D side.
Overview of Existing Wind Energy Ordinances
Oteri, F.
2008-12-01
Due to increased energy demand in the United States, rural communities with limited or no experience with wind energy now have the opportunity to become involved in this industry. Communities with good wind resources may be approached by entities with plans to develop the resource. Although these opportunities can create new revenue in the form of construction jobs and land lease payments, they also create a new responsibility on the part of local governments to ensure that ordinances will be established to aid the development of safe facilities that will be embraced by the community. The purpose of this report is to educate and engage state and local governments, as well as policymakers, about existing large wind energy ordinances. These groups will have a collection of examples to utilize when they attempt to draft a new large wind energy ordinance in a town or county without existing ordinances.
3D PDF - a means of public access to geological 3D - objects, using the example of GTA3D
NASA Astrophysics Data System (ADS)
Slaby, Mark-Fabian; Reimann, Rüdiger
2013-04-01
In geology, 3D modeling has become very important. In the past, two-dimensional data such as isolines, drilling profiles, or cross-sections based on those, were used to illustrate the subsurface geology, whereas now, we can create complex digital 3D models. These models are produced with special software, such as GOCAD ®. The models can be viewed, only through the software used to create them, or through viewers available for free. The platform-independent PDF (Portable Document Format), enforced by Adobe, has found a wide distribution. This format has constantly evolved over time. Meanwhile, it is possible to display CAD data in an Adobe 3D PDF file with the free Adobe Reader (version 7). In a 3D PDF, a 3D model is freely rotatable and can be assembled from a plurality of objects, which can thus be viewed from all directions on their own. In addition, it is possible to create moveable cross-sections (profiles), and to assign transparency to the objects. Based on industry-standard CAD software, 3D PDFs can be generated from a large number of formats, or even be exported directly from this software. In geoinformatics, different approaches to creating 3D PDFs exist. The intent of the Authority for Mining, Energy and Geology to allow free access to the models of the Geotectonic Atlas (GTA3D), could not be realized with standard software solutions. A specially designed code converts the 3D objects to VRML (Virtual Reality Modeling Language). VRML is one of the few formats that allow using image files (maps) as textures, and to represent colors and shapes correctly. The files were merged in Acrobat X Pro, and a 3D PDF was generated subsequently. A topographic map, a display of geographic directions and horizontal and vertical scales help to facilitate the use.
3D ultrafast ultrasound imaging in vivo.
Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu
2014-10-01
Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32 × 32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra--and inter-observer variability.
3D ultrafast ultrasound imaging in vivo
NASA Astrophysics Data System (ADS)
Provost, Jean; Papadacci, Clement; Esteban Arango, Juan; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu
2014-10-01
Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32 × 32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra—and inter-observer variability.
3D ultrafast ultrasound imaging in vivo.
Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu
2014-10-01
Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32 × 32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra--and inter-observer variability. PMID:25207828
An aerial 3D printing test mission
NASA Astrophysics Data System (ADS)
Hirsch, Michael; McGuire, Thomas; Parsons, Michael; Leake, Skye; Straub, Jeremy
2016-05-01
This paper provides an overview of an aerial 3D printing technology, its development and its testing. This technology is potentially useful in its own right. In addition, this work advances the development of a related in-space 3D printing technology. A series of aerial 3D printing test missions, used to test the aerial printing technology, are discussed. Through completing these test missions, the design for an in-space 3D printer may be advanced. The current design for the in-space 3D printer involves focusing thermal energy to heat an extrusion head and allow for the extrusion of molten print material. Plastics can be used as well as composites including metal, allowing for the extrusion of conductive material. A variety of experiments will be used to test this initial 3D printer design. High altitude balloons will be used to test the effects of microgravity on 3D printing, as well as parabolic flight tests. Zero pressure balloons can be used to test the effect of long 3D printing missions subjected to low temperatures. Vacuum chambers will be used to test 3D printing in a vacuum environment. The results will be used to adapt a current prototype of an in-space 3D printer. Then, a small scale prototype can be sent into low-Earth orbit as a 3-U cube satellite. With the ability to 3D print in space demonstrated, future missions can launch production hardware through which the sustainability and durability of structures in space will be greatly improved.
Wow! 3D Content Awakens the Classroom
ERIC Educational Resources Information Center
Gordon, Dan
2010-01-01
From her first encounter with stereoscopic 3D technology designed for classroom instruction, Megan Timme, principal at Hamilton Park Pacesetter Magnet School in Dallas, sensed it could be transformative. Last spring, when she began pilot-testing 3D content in her third-, fourth- and fifth-grade classrooms, Timme wasn't disappointed. Students…
ERIC Educational Resources Information Center
Norbury, Keith
2012-01-01
It may be too soon for students to be showing up for class with popcorn and gummy bears, but technology similar to that behind the 3D blockbuster movie "Avatar" is slowly finding its way into college classrooms. 3D classroom projectors are taking students on fantastic voyages inside the human body, to the ruins of ancient Greece--even to faraway…
3D Printed Block Copolymer Nanostructures
ERIC Educational Resources Information Center
Scalfani, Vincent F.; Turner, C. Heath; Rupar, Paul A.; Jenkins, Alexander H.; Bara, Jason E.
2015-01-01
The emergence of 3D printing has dramatically advanced the availability of tangible molecular and extended solid models. Interestingly, there are few nanostructure models available both commercially and through other do-it-yourself approaches such as 3D printing. This is unfortunate given the importance of nanotechnology in science today. In this…
Immersive 3D Geovisualization in Higher Education
ERIC Educational Resources Information Center
Philips, Andrea; Walz, Ariane; Bergner, Andreas; Graeff, Thomas; Heistermann, Maik; Kienzler, Sarah; Korup, Oliver; Lipp, Torsten; Schwanghart, Wolfgang; Zeilinger, Gerold
2015-01-01
In this study, we investigate how immersive 3D geovisualization can be used in higher education. Based on MacEachren and Kraak's geovisualization cube, we examine the usage of immersive 3D geovisualization and its usefulness in a research-based learning module on flood risk, called GEOSimulator. Results of a survey among participating students…
3D elastic control for mobile devices.
Hachet, Martin; Pouderoux, Joachim; Guitton, Pascal
2008-01-01
To increase the input space of mobile devices, the authors developed a proof-of-concept 3D elastic controller that easily adapts to mobile devices. This embedded device improves the completion of high-level interaction tasks such as visualization of large documents and navigation in 3D environments. It also opens new directions for tomorrow's mobile applications.
Static & Dynamic Response of 3D Solids
1996-07-15
NIKE3D is a large deformations 3D finite element code used to obtain the resulting displacements and stresses from multi-body static and dynamic structural thermo-mechanics problems with sliding interfaces. Many nonlinear and temperature dependent constitutive models are available.
ERIC Educational Resources Information Center
Love, Tyler S.; Roy, Ken
2016-01-01
Health concerns from 3D printing were first documented by Stephens, Azimi, Orch, and Ramos (2013), who found that commercially available 3D printers were producing hazardous levels of ultrafine particles (UFPs) and volatile organic compounds (VOCs) when plastic materials were melted through the extruder. UFPs are particles less than 100 nanometers…
3D Printing of Molecular Models
ERIC Educational Resources Information Center
Gardner, Adam; Olson, Arthur
2016-01-01
Physical molecular models have played a valuable role in our understanding of the invisible nano-scale world. We discuss 3D printing and its use in producing models of the molecules of life. Complex biomolecular models, produced from 3D printed parts, can demonstrate characteristics of molecular structure and function, such as viral self-assembly,…
A 3D Geostatistical Mapping Tool
Weiss, W. W.; Stevenson, Graig; Patel, Ketan; Wang, Jun
1999-02-09
This software provides accurate 3D reservoir modeling tools and high quality 3D graphics for PC platforms enabling engineers and geologists to better comprehend reservoirs and consequently improve their decisions. The mapping algorithms are fractals, kriging, sequential guassian simulation, and three nearest neighbor methods.
Pathways for Learning from 3D Technology
ERIC Educational Resources Information Center
Carrier, L. Mark; Rab, Saira S.; Rosen, Larry D.; Vasquez, Ludivina; Cheever, Nancy A.
2012-01-01
The purpose of this study was to find out if 3D stereoscopic presentation of information in a movie format changes a viewer's experience of the movie content. Four possible pathways from 3D presentation to memory and learning were considered: a direct connection based on cognitive neuroscience research; a connection through "immersion" in that 3D…
Stereo 3-D Vision in Teaching Physics
ERIC Educational Resources Information Center
Zabunov, Svetoslav
2012-01-01
Stereo 3-D vision is a technology used to present images on a flat surface (screen, paper, etc.) and at the same time to create the notion of three-dimensional spatial perception of the viewed scene. A great number of physical processes are much better understood when viewed in stereo 3-D vision compared to standard flat 2-D presentation. The…
The Northwest Ordinance -- Our First National Bill of Rights.
ERIC Educational Resources Information Center
Baxter, Maurice
1988-01-01
Describes the Northwest Ordinance as the nation's first bill of rights and discusses the similarities between the Ordinance and state constitutions. States that neither the Ordinance nor the state constitutions mentioned freedom of speech. Contends that the Ordinance was one of the "foundation stones" in the structure of U.S. liberty. (BSR)
NASA Astrophysics Data System (ADS)
Portal, Angélie; Fargier, Yannick; Lénat, Jean-François; Labazuy, Philippe
2016-04-01
The electrical resistivity tomography (ERT) method, initially developed for environmental and engineering exploration, is now commonly used for geological structures imaging. Such structures can present complex characteristics that conventional 2D inversion processes cannot perfectly integrate. Here we present a new 3D inversion algorithm named EResI, firstly developed for levee investigation, and presently applied to the study of a complex lava dome (the Puy de Dôme volcano, France). EResI algorithm is based on a conventional regularized Gauss-Newton inversion scheme and a 3D non-structured discretization of the model (double grid method based on tetrahedrons). This discretization allows to accurately model the topography of investigated structure (without a mesh deformation procedure) and also permits a precise location of the electrodes. Moreover, we demonstrate that a complete 3D unstructured discretization limits the number of inversion cells and is better adapted to the resolution capacity of tomography than a structured discretization. This study shows that a 3D inversion with a non-structured parametrization has some advantages compared to classical 2D inversions. The first advantage comes from the fact that a 2D inversion leads to artefacts due to 3D effects (3D topography, 3D internal resistivity). The second advantage comes from the fact that the capacity to experimentally align electrodes along an axis (for 2D surveys) depends on the constrains on the field (topography...). In this case, a 2D assumption induced by 2.5D inversion software prevents its capacity to model electrodes outside this axis leading to artefacts in the inversion result. The last limitation comes from the use of mesh deformation techniques used to accurately model the topography in 2D softwares. This technique used for structured discretization (Res2dinv) is prohibed for strong topography (>60 %) and leads to a small computational errors. A wide geophysical survey was carried out
3D magnetotelluric inversion with full distortion matrix
NASA Astrophysics Data System (ADS)
Gribenko, A. V.; Zhdanov, M. S.
2014-12-01
Distortion of regional electric fields by local structures represent one of the major problems facing three-dimensional magnetotelluric (MT) interpretation. Effect of 3D local inhomogenities on MT data can be described by a real 2x2 distortion matrix. In this project we develop a method of simultaneous inversion of the full MT impedance data for 3D conductivity distribution and for the distortion matrix. Tikhonov regularization is employed to solve the resulting inverse problem. Integral equations method is used to compute MT responses. Minimization of the cost functional is achieved via conjugate gradient method. The inversion algorithm is tested on the synthetic data from Dublin Secret Model II (DSM 2) for which multiple inversion solutions are available for comparison. Inclusion of the distortion matrix provides faster convergence and allows coarser discretization of the near-surface while achievingsimilar or better data fits as inversion for the conductivity only with finely discretized shallow regions. As a field data example we chose a subset of the EarthScope MT dataset covering Great Basin and adjacent areas of the Western United States. Great Basin data inversion identified several prominent conductive zones which correlate well with areas of tectonic and geothermal activity.
Clinical applications of 3-D dosimeters
NASA Astrophysics Data System (ADS)
Wuu, Cheng-Shie
2015-01-01
Both 3-D gels and radiochromic plastic dosimeters, in conjunction with dose image readout systems (MRI or optical-CT), have been employed to measure 3-D dose distributions in many clinical applications. The 3-D dose maps obtained from these systems can provide a useful tool for clinical dose verification for complex treatment techniques such as IMRT, SRS/SBRT, brachytherapy, and proton beam therapy. These complex treatments present high dose gradient regions in the boundaries between the target and surrounding critical organs. Dose accuracy in these areas can be critical, and may affect treatment outcome. In this review, applications of 3-D gels and PRESAGE dosimeter are reviewed and evaluated in terms of their performance in providing information on clinical dose verification as well as commissioning of various treatment modalities. Future interests and clinical needs on studies of 3-D dosimetry are also discussed.
Fabrication of 3D Silicon Sensors
Kok, A.; Hansen, T.E.; Hansen, T.A.; Lietaer, N.; Summanwar, A.; Kenney, C.; Hasi, J.; Da Via, C.; Parker, S.I.; /Hawaii U.
2012-06-06
Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated the original (single sided double column type) 3D detectors in two prototype runs and the third run is now on-going. This paper reports the status of this fabrication work and the resulted yield. The work of other groups such as the development of double sided 3D detectors is also briefly reported.
BEAMS3D Neutral Beam Injection Model
Lazerson, Samuel
2014-04-14
With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.
Efficient and high speed depth-based 2D to 3D video conversion
NASA Astrophysics Data System (ADS)
Somaiya, Amisha Himanshu; Kulkarni, Ramesh K.
2013-09-01
Stereoscopic video is the new era in video viewing and has wide applications such as medicine, satellite imaging and 3D Television. Such stereo content can be generated directly using S3D cameras. However, this approach requires expensive setup and hence converting monoscopic content to S3D becomes a viable approach. This paper proposes a depth-based algorithm for monoscopic to stereoscopic video conversion by using the y axis co-ordinates of the bottom-most pixels of foreground objects. This code can be used for arbitrary videos without prior database training. It does not face the limitations of single monocular depth cues nor does it combine depth cues, thus consuming less processing time without affecting the efficiency of the 3D video output. The algorithm, though not comparable to real-time, is faster than the other available 2D to 3D video conversion techniques in the average ratio of 1:8 to 1:20, essentially qualifying as high-speed. It is an automatic conversion scheme, hence directly gives the 3D video output without human intervention and with the above mentioned features becomes an ideal choice for efficient monoscopic to stereoscopic video conversion. [Figure not available: see fulltext.
3D Ultrafast Ultrasound Imaging In Vivo
Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu
2014-01-01
Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative real-time imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in three dimensions based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32×32 matrix-array probe. Its capability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3-D Shear-Wave Imaging, 3-D Ultrafast Doppler Imaging and finally 3D Ultrafast combined Tissue and Flow Doppler. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3-D Ultrafast Doppler was used to obtain 3-D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, for the first time, the complex 3-D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, and the 3-D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3-D Ultrafast Ultrasound Imaging for the 3-D real-time mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra- and inter-observer variability. PMID:25207828
The psychology of the 3D experience
NASA Astrophysics Data System (ADS)
Janicke, Sophie H.; Ellis, Andrew
2013-03-01
With 3D televisions expected to reach 50% home saturation as early as 2016, understanding the psychological mechanisms underlying the user response to 3D technology is critical for content providers, educators and academics. Unfortunately, research examining the effects of 3D technology has not kept pace with the technology's rapid adoption, resulting in large-scale use of a technology about which very little is actually known. Recognizing this need for new research, we conducted a series of studies measuring and comparing many of the variables and processes underlying both 2D and 3D media experiences. In our first study, we found narratives within primetime dramas had the power to shift viewer attitudes in both 2D and 3D settings. However, we found no difference in persuasive power between 2D and 3D content. We contend this lack of effect was the result of poor conversion quality and the unique demands of 3D production. In our second study, we found 3D technology significantly increased enjoyment when viewing sports content, yet offered no added enjoyment when viewing a movie trailer. The enhanced enjoyment of the sports content was shown to be the result of heightened emotional arousal and attention in the 3D condition. We believe the lack of effect found for the movie trailer may be genre-related. In our final study, we found 3D technology significantly enhanced enjoyment of two video games from different genres. The added enjoyment was found to be the result of an increased sense of presence.
Low-cost 3D rangefinder system
NASA Astrophysics Data System (ADS)
Chen, Bor-Tow; Lou, Wen-Shiou; Chen, Chia-Chen; Lin, Hsien-Chang
1998-06-01
Nowadays, 3D data are popularly performed in computer, and 3D browsers manipulate 3D model in the virtual world. Yet, till now, 3D digitizer is still a high-cost product and not a familiar equipment. In order to meet the requirement of 3D fancy world, in this paper, the concept of a low-cost 3D digitizer system is proposed to catch 3D range data from objects. The specified optical design of the 3D extraction is effective to depress the size, and the processing software of the system is compatible with PC to promote its portable capability. Both features contribute a low-cost system in PC environment in contrast to a large system bundled in an expensive workstation platform. In the structure of 3D extraction, laser beam and CCD camera are adopted to construct a 3D sensor. Instead of 2 CCD cameras for capturing laser lines twice before, a 2-in-1 system is proposed to merge 2 images in one CCD which still retains the information of two fields of views to inhibit occlusion problems. Besides, optical paths of two camera views are reflected by mirror in order that the volume of the system can be minified with one rotary axis only. It makes a portable system be more possible to work. Combined with the processing software executable in PC windows system, the proposed system not only saves hardware cost but also processing time of software. The system performance achieves 0.05 mm accuracy. It shows that a low- cost system is more possible to be high-performance.
3D Visualization Development of SIUE Campus
NASA Astrophysics Data System (ADS)
Nellutla, Shravya
Geographic Information Systems (GIS) has progressed from the traditional map-making to the modern technology where the information can be created, edited, managed and analyzed. Like any other models, maps are simplified representations of real world. Hence visualization plays an essential role in the applications of GIS. The use of sophisticated visualization tools and methods, especially three dimensional (3D) modeling, has been rising considerably due to the advancement of technology. There are currently many off-the-shelf technologies available in the market to build 3D GIS models. One of the objectives of this research was to examine the available ArcGIS and its extensions for 3D modeling and visualization and use them to depict a real world scenario. Furthermore, with the advent of the web, a platform for accessing and sharing spatial information on the Internet, it is possible to generate interactive online maps. Integrating Internet capacity with GIS functionality redefines the process of sharing and processing the spatial information. Enabling a 3D map online requires off-the-shelf GIS software, 3D model builders, web server, web applications and client server technologies. Such environments are either complicated or expensive because of the amount of hardware and software involved. Therefore, the second objective of this research was to investigate and develop simpler yet cost-effective 3D modeling approach that uses available ArcGIS suite products and the free 3D computer graphics software for designing 3D world scenes. Both ArcGIS Explorer and ArcGIS Online will be used to demonstrate the way of sharing and distributing 3D geographic information on the Internet. A case study of the development of 3D campus for the Southern Illinois University Edwardsville is demonstrated.
Advancements in 3D Structural Analysis of Geothermal Systems
Siler, Drew L; Faulds, James E; Mayhew, Brett; McNamara, David
2013-06-23
Robust geothermal activity in the Great Basin, USA is a product of both anomalously high regional heat flow and active fault-controlled extension. Elevated permeability associated with some fault systems provides pathways for circulation of geothermal fluids. Constraining the local-scale 3D geometry of these structures and their roles as fluid flow conduits is crucial in order to mitigate both the costs and risks of geothermal exploration and to identify blind (no surface expression) geothermal resources. Ongoing studies have indicated that much of the robust geothermal activity in the Great Basin is associated with high density faulting at structurally complex fault intersection/interaction areas, such as accommodation/transfer zones between discrete fault systems, step-overs or relay ramps in fault systems, intersection zones between faults with different strikes or different senses of slip, and horse-tailing fault terminations. These conceptualized models are crucial for locating and characterizing geothermal systems in a regional context. At the local scale, however, pinpointing drilling targets and characterizing resource potential within known or probable geothermal areas requires precise 3D characterization of the system. Employing a variety of surface and subsurface data sets, we have conducted detailed 3D geologic analyses of two Great Basin geothermal systems. Using EarthVision (Dynamic Graphics Inc., Alameda, CA) we constructed 3D geologic models of both the actively producing Brady’s geothermal system and a ‘greenfield’ geothermal prospect at Astor Pass, NV. These 3D models allow spatial comparison of disparate data sets in 3D and are the basis for quantitative structural analyses that can aid geothermal resource assessment and be used to pinpoint discrete drilling targets. The relatively abundant data set at Brady’s, ~80 km NE of Reno, NV, includes 24 wells with lithologies interpreted from careful analysis of cuttings and core, a 1
Medical 3D Printing for the Radiologist.
Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A; Cai, Tianrun; Kumamaru, Kanako K; George, Elizabeth; Wake, Nicole; Caterson, Edward J; Pomahac, Bohdan; Ho, Vincent B; Grant, Gerald T; Rybicki, Frank J
2015-01-01
While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article.
3D facial expression modeling for recognition
NASA Astrophysics Data System (ADS)
Lu, Xiaoguang; Jain, Anil K.; Dass, Sarat C.
2005-03-01
Current two-dimensional image based face recognition systems encounter difficulties with large variations in facial appearance due to the pose, illumination and expression changes. Utilizing 3D information of human faces is promising for handling the pose and lighting variations. While the 3D shape of a face does not change due to head pose (rigid) and lighting changes, it is not invariant to the non-rigid facial movement and evolution, such as expressions and aging effect. We propose a facial surface matching framework to match multiview facial scans to a 3D face model, where the (non-rigid) expression deformation is explicitly modeled for each subject, resulting in a person-specific deformation model. The thin plate spline (TPS) is applied to model the deformation based on the facial landmarks. The deformation is applied to the 3D neutral expression face model to synthesize the corresponding expression. Both the neutral and the synthesized 3D surface models are used to match a test scan. The surface registration and matching between a test scan and a 3D model are achieved by a modified Iterative Closest Point (ICP) algorithm. Preliminary experimental results demonstrate that the proposed expression modeling and recognition-by-synthesis schemes improve the 3D matching accuracy.
Digital relief generation from 3D models
NASA Astrophysics Data System (ADS)
Wang, Meili; Sun, Yu; Zhang, Hongming; Qian, Kun; Chang, Jian; He, Dongjian
2016-09-01
It is difficult to extend image-based relief generation to high-relief generation, as the images contain insufficient height information. To generate reliefs from three-dimensional (3D) models, it is necessary to extract the height fields from the model, but this can only generate bas-reliefs. To overcome this problem, an efficient method is proposed to generate bas-reliefs and high-reliefs directly from 3D meshes. To produce relief features that are visually appropriate, the 3D meshes are first scaled. 3D unsharp masking is used to enhance the visual features in the 3D mesh, and average smoothing and Laplacian smoothing are implemented to achieve better smoothing results. A nonlinear variable scaling scheme is then employed to generate the final bas-reliefs and high-reliefs. Using the proposed method, relief models can be generated from arbitrary viewing positions with different gestures and combinations of multiple 3D models. The generated relief models can be printed by 3D printers. The proposed method provides a means of generating both high-reliefs and bas-reliefs in an efficient and effective way under the appropriate scaling factors.
NUBEAM developments and 3d halo modeling
NASA Astrophysics Data System (ADS)
Gorelenkova, M. V.; Medley, S. S.; Kaye, S. M.
2012-10-01
Recent developments related to the 3D halo model in NUBEAM code are described. To have a reliable halo neutral source for diagnostic simulation, the TRANSP/NUBEAM code has been enhanced with full implementation of ADAS atomic physic ground state and excited state data for hydrogenic beams and mixed species plasma targets. The ADAS codes and database provide the density and temperature dependence of the atomic data, and the collective nature of the state excitation process. To be able to populate 3D halo output with sufficient statistical resolution, the capability to control the statistics of fast ion CX modeling and for thermal halo launch has been added to NUBEAM. The 3D halo neutral model is based on modification and extension of the ``beam in box'' aligned 3d Cartesian grid that includes the neutral beam itself, 3D fast neutral densities due to CX of partially slowed down fast ions in the beam halo region, 3D thermal neutral densities due to CX deposition and fast neutral recapture source. More details on the 3D halo simulation design will be presented.
Medical 3D Printing for the Radiologist.
Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A; Cai, Tianrun; Kumamaru, Kanako K; George, Elizabeth; Wake, Nicole; Caterson, Edward J; Pomahac, Bohdan; Ho, Vincent B; Grant, Gerald T; Rybicki, Frank J
2015-01-01
While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article. PMID:26562233
Perception of detail in 3D images
NASA Astrophysics Data System (ADS)
Heynderickx, Ingrid; Kaptein, Ronald
2009-01-01
A lot of current 3D displays suffer from the fact that their spatial resolution is lower compared to their 2D counterparts. One reason for this is that the multiple views needed to generate 3D are often spatially multiplexed. Besides this, imperfect separation of the left- and right-eye view leads to blurring or ghosting, and therefore to a decrease in perceived sharpness. However, people watching stereoscopic videos have reported that the 3D scene contained more details, compared to the 2D scene with identical spatial resolution. This is an interesting notion, that has never been tested in a systematic and quantitative way. To investigate this effect, we had people compare the amount of detail ("detailedness") in pairs of 2D and 3D images. A blur filter was applied to one of the two images, and the blur level was varied using an adaptive staircase procedure. In this way, the blur threshold for which the 2D and 3D image contained perceptually the same amount of detail could be found. Our results show that the 3D image needed to be blurred more than the 2D image. This confirms the earlier qualitative findings that 3D images contain perceptually more details than 2D images with the same spatial resolution.
3D bioprinting of tissues and organs.
Murphy, Sean V; Atala, Anthony
2014-08-01
Additive manufacturing, otherwise known as three-dimensional (3D) printing, is driving major innovations in many areas, such as engineering, manufacturing, art, education and medicine. Recent advances have enabled 3D printing of biocompatible materials, cells and supporting components into complex 3D functional living tissues. 3D bioprinting is being applied to regenerative medicine to address the need for tissues and organs suitable for transplantation. Compared with non-biological printing, 3D bioprinting involves additional complexities, such as the choice of materials, cell types, growth and differentiation factors, and technical challenges related to the sensitivities of living cells and the construction of tissues. Addressing these complexities requires the integration of technologies from the fields of engineering, biomaterials science, cell biology, physics and medicine. 3D bioprinting has already been used for the generation and transplantation of several tissues, including multilayered skin, bone, vascular grafts, tracheal splints, heart tissue and cartilaginous structures. Other applications include developing high-throughput 3D-bioprinted tissue models for research, drug discovery and toxicology. PMID:25093879
Medical 3D Printing for the Radiologist
Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A.; Cai, Tianrun; Kumamaru, Kanako K.; George, Elizabeth; Wake, Nicole; Caterson, Edward J.; Pomahac, Bohdan; Ho, Vincent B.; Grant, Gerald T.
2015-01-01
While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article. ©RSNA, 2015 PMID:26562233
Blind watermark algorithm on 3D motion model based on wavelet transform
NASA Astrophysics Data System (ADS)
Qi, Hu; Zhai, Lang
2013-12-01
With the continuous development of 3D vision technology, digital watermark technology, as the best choice for copyright protection, has fused with it gradually. This paper proposed a blind watermark plan of 3D motion model based on wavelet transform, and made it loaded into the Vega real-time visual simulation system. Firstly, put 3D model into affine transform, and take the distance from the center of gravity to the vertex of 3D object in order to generate a one-dimensional discrete signal; then make this signal into wavelet transform to change its frequency coefficients and embed watermark, finally generate 3D motion model with watermarking. In fixed affine space, achieve the robustness in translation, revolving and proportion transforms. The results show that this approach has better performances not only in robustness, but also in watermark- invisibility.
Extra Dimensions: 3D in PDF Documentation
NASA Astrophysics Data System (ADS)
Graf, Norman A.
2012-12-01
Experimental science is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) and the ISO PRC file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. Until recently, Adobe's Acrobat software was also capable of incorporating 3D content into PDF files from a variety of 3D file formats, including proprietary CAD formats. However, this functionality is no longer available in Acrobat X, having been spun off to a separate company. Incorporating 3D content now requires the additional purchase of a separate plug-in. In this talk we present alternatives based on open source libraries which allow the programmatic creation of 3D content in PDF format. While not providing the same level of access to CAD files as the commercial software, it does provide physicists with an alternative path to incorporate 3D content into PDF files from such disparate applications as detector geometries from Geant4, 3D data sets, mathematical surfaces or tesselated volumes.
VALIDATION OF IMPROVED 3D ATR MODEL
Soon Sam Kim; Bruce G. Schnitzler
2005-11-01
A full-core Monte Carlo based 3D model of the Advanced Test Reactor (ATR) was previously developed. [1] An improved 3D model has been developed by the International Criticality Safety Benchmark Evaluation Project (ICSBEP) to eliminate homogeneity of fuel plates of the old model, incorporate core changes into the new model, and to validate against a newer, more complicated core configuration. This new 3D model adds capability for fuel loading design and azimuthal power peaking studies of the ATR fuel elements.
Explicit 3-D Hydrodynamic FEM Program
2000-11-07
DYNA3D is a nonlinear explicit finite element code for analyzing 3-D structures and solid continuum. The code is vectorized and available on several computer platforms. The element library includes continuum, shell, beam, truss and spring/damper elements to allow maximum flexibility in modeling physical problems. Many materials are available to represent a wide range of material behavior, including elasticity, plasticity, composites, thermal effects and rate dependence. In addition, DYNA3D has a sophisticated contact interface capability, includingmore » frictional sliding, single surface contact and automatic contact generation.« less
A high capacity 3D steganography algorithm.
Chao, Min-Wen; Lin, Chao-hung; Yu, Cheng-Wei; Lee, Tong-Yee
2009-01-01
In this paper, we present a very high-capacity and low-distortion 3D steganography scheme. Our steganography approach is based on a novel multilayered embedding scheme to hide secret messages in the vertices of 3D polygon models. Experimental results show that the cover model distortion is very small as the number of hiding layers ranges from 7 to 13 layers. To the best of our knowledge, this novel approach can provide much higher hiding capacity than other state-of-the-art approaches, while obeying the low distortion and security basic requirements for steganography on 3D models.
2015-04-23
A new type of graphene aerogel will make for better energy storage, sensors, nanoelectronics, catalysis and separations. Lawrence Livermore National Laboratory researchers have made graphene aerogel microlattices with an engineered architecture via a 3D printing technique known as direct ink writing. The research appears in the April 22 edition of the journal, Nature Communications. The 3D printed graphene aerogels have high surface area, excellent electrical conductivity, are lightweight, have mechanical stiffness and exhibit supercompressibility (up to 90 percent compressive strain). In addition, the 3D printed graphene aerogel microlattices show an order of magnitude improvement over bulk graphene materials and much better mass transport.
FIT3D: Fitting optical spectra
NASA Astrophysics Data System (ADS)
Sánchez, S. F.; Pérez, E.; Sánchez-Blázquez, P.; González, J. J.; Rosales-Ortega, F. F.; Cano-Díaz, M.; López-Cobá, C.; Marino, R. A.; Gil de Paz, A.; Mollá, M.; López-Sánchez, A. R.; Ascasibar, Y.; Barrera-Ballesteros, J.
2016-09-01
FIT3D fits optical spectra to deblend the underlying stellar population and the ionized gas, and extract physical information from each component. FIT3D is focused on the analysis of Integral Field Spectroscopy data, but is not restricted to it, and is the basis of Pipe3D, a pipeline used in the analysis of datasets like CALIFA, MaNGA, and SAMI. It can run iteratively or in an automatic way to derive the parameters of a large set of spectra.
3D packaging for integrated circuit systems
Chu, D.; Palmer, D.W.
1996-11-01
A goal was set for high density, high performance microelectronics pursued through a dense 3D packing of integrated circuits. A {open_quotes}tool set{close_quotes} of assembly processes have been developed that enable 3D system designs: 3D thermal analysis, silicon electrical through vias, IC thinning, mounting wells in silicon, adhesives for silicon stacking, pretesting of IC chips before commitment to stacks, and bond pad bumping. Validation of these process developments occurred through both Sandia prototypes and subsequent commercial examples.
Investigations in massive 3D gravity
Accioly, Antonio; Helayeel-Neto, Jose; Morais, Jefferson; Turcati, Rodrigo; Scatena, Eslley
2011-05-15
Some interesting gravitational properties of the Bergshoeff-Hohm-Townsend model (massive 3D gravity), such as the presence of a short-range gravitational force in the nonrelativistic limit and the existence of an impact-parameter-dependent gravitational deflection angle, are studied. Interestingly enough, these phenomena have no counterpart in the usual Einstein 3D gravity. In order to better understand the two aforementioned gravitational properties, they are also analyzed in the framework of 3D higher-derivative gravity with the Einstein-Hilbert term with the 'wrong sign'.
An Improved Version of TOPAZ 3D
Krasnykh, Anatoly
2003-07-29
An improved version of the TOPAZ 3D gun code is presented as a powerful tool for beam optics simulation. In contrast to the previous version of TOPAZ 3D, the geometry of the device under test is introduced into TOPAZ 3D directly from a CAD program, such as Solid Edge or AutoCAD. In order to have this new feature, an interface was developed, using the GiD software package as a meshing code. The article describes this method with two models to illustrate the results.
3D model generation using an airborne swarm
NASA Astrophysics Data System (ADS)
Clark, R. A.; Punzo, G.; Dobie, G.; MacLeod, C. N.; Summan, R.; Pierce, G.; Macdonald, M.; Bolton, G.
2015-03-01
Using an artificial kinematic field to provide co-ordination between multiple inspection UAVs, the authors herein demonstrate full 3D modelling capability based on a photogrammetric system. The operation of the system is demonstrated by generating a full 3D surface model of an intermediate level nuclear waste storage drum. Such drums require periodic inspection to ensure that drum distortion or corrosion is carefully monitored. Performing this inspection with multiple airborne platforms enables rapid inspection of structures that are inaccessible to on-surface remote vehicles and are in human-hazardous environments. A three-dimensional surface-meshed model of the target can then be constructed in post-processing through photogrammetry analysis of the visual inspection data. The inspection environment uses a tracking system to precisely monitor the position of each aerial vehicle within the enclosure. The vehicles used are commercially available Parrot AR. Drone quadcopters, controlled through a computer interface connected over an IEEE 802.11n (WiFi) network, implementing a distributed controller for each vehicle. This enables the autonomous and distributed elements of the control scheme to be retained, while alleviating the vehicles of the control algorithm's computational load. The control scheme relies on a kinematic field defined with the target at its centre. This field defines the trajectory for all the drones in the volume relative to the central target, enabling the drones to circle the target at a set radius while avoiding drone collisions. This function enables complete coverage along the height of the object, which is assured by transitioning to another inspection band only after completing circumferential coverage. Using a swarm of vehicles, the time until complete coverage can be significantly reduced.
3D model generation using an airborne swarm
Clark, R. A.; Punzo, G.; Macdonald, M.; Dobie, G.; MacLeod, C. N.; Summan, R.; Pierce, G.; Bolton, G.
2015-03-31
Using an artificial kinematic field to provide co-ordination between multiple inspection UAVs, the authors herein demonstrate full 3D modelling capability based on a photogrammetric system. The operation of the system is demonstrated by generating a full 3D surface model of an intermediate level nuclear waste storage drum. Such drums require periodic inspection to ensure that drum distortion or corrosion is carefully monitored. Performing this inspection with multiple airborne platforms enables rapid inspection of structures that are inaccessible to on-surface remote vehicles and are in human-hazardous environments. A three-dimensional surface-meshed model of the target can then be constructed in post-processing through photogrammetry analysis of the visual inspection data. The inspection environment uses a tracking system to precisely monitor the position of each aerial vehicle within the enclosure. The vehicles used are commercially available Parrot AR. Drone quadcopters, controlled through a computer interface connected over an IEEE 802.11n (WiFi) network, implementing a distributed controller for each vehicle. This enables the autonomous and distributed elements of the control scheme to be retained, while alleviating the vehicles of the control algorithm’s computational load. The control scheme relies on a kinematic field defined with the target at its centre. This field defines the trajectory for all the drones in the volume relative to the central target, enabling the drones to circle the target at a set radius while avoiding drone collisions. This function enables complete coverage along the height of the object, which is assured by transitioning to another inspection band only after completing circumferential coverage. Using a swarm of vehicles, the time until complete coverage can be significantly reduced.
JAR3D Webserver: Scoring and aligning RNA loop sequences to known 3D motifs
Roll, James; Zirbel, Craig L.; Sweeney, Blake; Petrov, Anton I.; Leontis, Neocles
2016-01-01
Many non-coding RNAs have been identified and may function by forming 2D and 3D structures. RNA hairpin and internal loops are often represented as unstructured on secondary structure diagrams, but RNA 3D structures show that most such loops are structured by non-Watson–Crick basepairs and base stacking. Moreover, different RNA sequences can form the same RNA 3D motif. JAR3D finds possible 3D geometries for hairpin and internal loops by matching loop sequences to motif groups from the RNA 3D Motif Atlas, by exact sequence match when possible, and by probabilistic scoring and edit distance for novel sequences. The scoring gauges the ability of the sequences to form the same pattern of interactions observed in 3D structures of the motif. The JAR3D webserver at http://rna.bgsu.edu/jar3d/ takes one or many sequences of a single loop as input, or else one or many sequences of longer RNAs with multiple loops. Each sequence is scored against all current motif groups. The output shows the ten best-matching motif groups. Users can align input sequences to each of the motif groups found by JAR3D. JAR3D will be updated with every release of the RNA 3D Motif Atlas, and so its performance is expected to improve over time. PMID:27235417
XML3D and Xflow: combining declarative 3D for the Web with generic data flows.
Klein, Felix; Sons, Kristian; Rubinstein, Dmitri; Slusallek, Philipp
2013-01-01
Researchers have combined XML3D, which provides declarative, interactive 3D scene descriptions based on HTML5, with Xflow, a language for declarative, high-performance data processing. The result lets Web developers combine a 3D scene graph with data flows for dynamic meshes, animations, image processing, and postprocessing. PMID:24808080
Do-It-Yourself: 3D Models of Hydrogenic Orbitals through 3D Printing
ERIC Educational Resources Information Center
Griffith, Kaitlyn M.; de Cataldo, Riccardo; Fogarty, Keir H.
2016-01-01
Introductory chemistry students often have difficulty visualizing the 3-dimensional shapes of the hydrogenic electron orbitals without the aid of physical 3D models. Unfortunately, commercially available models can be quite expensive. 3D printing offers a solution for producing models of hydrogenic orbitals. 3D printing technology is widely…
Missing ordinal patterns in correlated noises
NASA Astrophysics Data System (ADS)
Carpi, Laura C.; Saco, Patricia M.; Rosso, O. A.
2010-05-01
Recent research aiming at the distinction between deterministic or stochastic behavior in observational time series has looked into the properties of the “ordinal patterns” [C. Bandt, B. Pompe, Phys. Rev. Lett. 88 (2002) 174102]. In particular, new insight has been obtained considering the emergence of the so-called “forbidden ordinal patterns” [J.M. Amigó, S. Zambrano, M.A. F Sanjuán, Europhys. Lett. 79 (2007) 50001]. It was shown that deterministic one-dimensional maps always have forbidden ordinal patterns, in contrast with time series generated by an unconstrained stochastic process in which all the patterns appear with probability one. Techniques based on the comparison of this property in an observational time series and in white Gaussian noise were implemented. However, the comparison with correlated stochastic processes was not considered. In this paper we used the concept of “missing ordinal patterns” to study their decay rate as a function of the time series length in three stochastic processes with different degrees of correlation: fractional Brownian motion, fractional Gaussian noise and, noises with f power spectrum. We show that the decay rate of “missing ordinal patterns” in these processes depend on their correlation structures. We finally discuss the implications of the present results for the use of these properties as a tool for distinguishing deterministic from stochastic processes.
Ordinality and novel sequence learning in jackdaws.
Pfuhl, G; Biegler, R
2012-09-01
A hallmark of higher cognition is the flexible use of information. This requires an abstract representation of the information. In sequence learning, ordinal position knowledge is seen as a more versatile representation when compared to chaining. Here, we assessed which of these mental representations is the most natural and most dominant in jackdaws. Two jackdaws (Corvus monedula) were trained on 14 separate three-item sequences (triplets), made up of abstract images. On each trial, the three items of one triplet were presented in fixed order. The images represented either the first, second or third ordinal position. Test stimuli consisted of the three images and a distractor image that was chosen randomly from the remaining sequences. We rewarded pecking in the correct order to the images belonging to the same sequence. The most common error the birds made was to peck at a distractor item from the same ordinal position. To look at how versatile the jackdaws' ordinal knowledge was, we replaced a familiar item with a novel item in some sequences. We then created novel sequences with these items, which the birds completed correctly. It appears, then, that jackdaws have a concept of ordinal position.
This 3-D flyby of Tropical Storm Ingrid's rainfall was created from TRMM satellite data for Sept. 16. Heaviest rainfall appears in red towers over the Gulf of Mexico, while moderate rainfall stretc...
3DSEM: A 3D microscopy dataset.
Tafti, Ahmad P; Kirkpatrick, Andrew B; Holz, Jessica D; Owen, Heather A; Yu, Zeyun
2016-03-01
The Scanning Electron Microscope (SEM) as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples. PMID:26779561
3DSEM: A 3D microscopy dataset
Tafti, Ahmad P.; Kirkpatrick, Andrew B.; Holz, Jessica D.; Owen, Heather A.; Yu, Zeyun
2015-01-01
The Scanning Electron Microscope (SEM) as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples. PMID:26779561
Tropical Cyclone Jack in Satellite 3-D
This 3-D flyby from NASA's TRMM satellite of Tropical Cyclone Jack on April 21 shows that some of the thunderstorms were shown by TRMM PR were still reaching height of at least 17 km (10.5 miles). ...
An Augmented Reality based 3D Catalog
NASA Astrophysics Data System (ADS)
Yamada, Ryo; Kishimoto, Katsumi
This paper presents a 3D catalog system that uses Augmented Reality technology. The use of Web-based catalog systems that present products in 3D form is increasing in various fields, along with the rapid and widespread adoption of Electronic Commerce. However, 3D shapes could previously only be seen in a virtual space, and it was difficult to understand how the products would actually look in the real world. To solve this, we propose a method that combines the virtual and real worlds simply and intuitively. The method applies Augmented Reality technology, and the system developed based on the method enables users to evaluate 3D virtual products in a real environment.
3D-printed bioanalytical devices.
Bishop, Gregory W; Satterwhite-Warden, Jennifer E; Kadimisetty, Karteek; Rusling, James F
2016-07-15
While 3D printing technologies first appeared in the 1980s, prohibitive costs, limited materials, and the relatively small number of commercially available printers confined applications mainly to prototyping for manufacturing purposes. As technologies, printer cost, materials, and accessibility continue to improve, 3D printing has found widespread implementation in research and development in many disciplines due to ease-of-use and relatively fast design-to-object workflow. Several 3D printing techniques have been used to prepare devices such as milli- and microfluidic flow cells for analyses of cells and biomolecules as well as interfaces that enable bioanalytical measurements using cellphones. This review focuses on preparation and applications of 3D-printed bioanalytical devices.
Cyclone Rusty's Landfall in 3-D
This 3-D image derived from NASA's TRMM satellite Precipitation Radar data on February 26, 2013 at 0654 UTC showed that the tops of some towering thunderstorms in Rusty's eye wall were reaching hei...
3-D Animation of Typhoon Bopha
This 3-D animation of NASA's TRMM satellite data showed Typhoon Bopha tracking over the Philippines on Dec. 3 and moving into the Sulu Sea on Dec. 4, 2012. TRMM saw heavy rain (red) was falling at ...
Palacios field: A 3-D case history
McWhorter, R.; Torguson, B.
1994-12-31
In late 1992, Mitchell Energy Corporation acquired a 7.75 sq mi (20.0 km{sup 2}) 3-D seismic survey over Palacios field. Matagorda County, Texas. The company shot the survey to help evaluate the field for further development by delineating the fault pattern of the producing Middle Oligocene Frio interval. They compare the mapping of the field before and after the 3-D survey. This comparison shows that the 3-D volume yields superior fault imaging and interpretability compared to the dense 2-D data set. The problems with the 2-D data set are improper imaging of small and oblique faults and insufficient coverage over a complex fault pattern. Whereas the 2-D data set validated a simple fault model, the 3-D volume revealed a more complex history of faulting that includes three different fault systems. This discovery enabled them to reconstruct the depositional and structural history of Palacios field.
3D-printed bioanalytical devices
NASA Astrophysics Data System (ADS)
Bishop, Gregory W.; Satterwhite-Warden, Jennifer E.; Kadimisetty, Karteek; Rusling, James F.
2016-07-01
While 3D printing technologies first appeared in the 1980s, prohibitive costs, limited materials, and the relatively small number of commercially available printers confined applications mainly to prototyping for manufacturing purposes. As technologies, printer cost, materials, and accessibility continue to improve, 3D printing has found widespread implementation in research and development in many disciplines due to ease-of-use and relatively fast design-to-object workflow. Several 3D printing techniques have been used to prepare devices such as milli- and microfluidic flow cells for analyses of cells and biomolecules as well as interfaces that enable bioanalytical measurements using cellphones. This review focuses on preparation and applications of 3D-printed bioanalytical devices.
3-D TRMM Flyby of Hurricane Amanda
The TRMM satellite flew over Hurricane Amanda on Tuesday, May 27 at 1049 UTC (6:49 a.m. EDT) and captured rainfall rates and cloud height data that was used to create this 3-D simulated flyby. Cred...
NASA Technical Reports Server (NTRS)
Kulikov, anton I.; Doronila, Paul R.; Nguyen, Viet T.; Jackson, Randal K.; Greene, William M.; Hussey, Kevin J.; Garcia, Christopher M.; Lopez, Christian A.
2013-01-01
Eyes on the Earth 3D software gives scientists, and the general public, a realtime, 3D interactive means of accurately viewing the real-time locations, speed, and values of recently collected data from several of NASA's Earth Observing Satellites using a standard Web browser (climate.nasa.gov/eyes). Anyone with Web access can use this software to see where the NASA fleet of these satellites is now, or where they will be up to a year in the future. The software also displays several Earth Science Data sets that have been collected on a daily basis. This application uses a third-party, 3D, realtime, interactive game engine called Unity 3D to visualize the satellites and is accessible from a Web browser.
3D Printing for Tissue Engineering
Jia, Jia; Yao, Hai; Mei, Ying
2016-01-01
Tissue engineering aims to fabricate functional tissue for applications in regenerative medicine and drug testing. More recently, 3D printing has shown great promise in tissue fabrication with a structural control from micro- to macro-scale by using a layer-by-layer approach. Whether through scaffold-based or scaffold-free approaches, the standard for 3D printed tissue engineering constructs is to provide a biomimetic structural environment that facilitates tissue formation and promotes host tissue integration (e.g., cellular infiltration, vascularization, and active remodeling). This review will cover several approaches that have advanced the field of 3D printing through novel fabrication methods of tissue engineering constructs. It will also discuss the applications of synthetic and natural materials for 3D printing facilitated tissue fabrication. PMID:26869728
3DSEM: A 3D microscopy dataset.
Tafti, Ahmad P; Kirkpatrick, Andrew B; Holz, Jessica D; Owen, Heather A; Yu, Zeyun
2016-03-01
The Scanning Electron Microscope (SEM) as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples.
3D-printed bioanalytical devices.
Bishop, Gregory W; Satterwhite-Warden, Jennifer E; Kadimisetty, Karteek; Rusling, James F
2016-07-15
While 3D printing technologies first appeared in the 1980s, prohibitive costs, limited materials, and the relatively small number of commercially available printers confined applications mainly to prototyping for manufacturing purposes. As technologies, printer cost, materials, and accessibility continue to improve, 3D printing has found widespread implementation in research and development in many disciplines due to ease-of-use and relatively fast design-to-object workflow. Several 3D printing techniques have been used to prepare devices such as milli- and microfluidic flow cells for analyses of cells and biomolecules as well as interfaces that enable bioanalytical measurements using cellphones. This review focuses on preparation and applications of 3D-printed bioanalytical devices. PMID:27250897
Nonlaser-based 3D surface imaging
Lu, Shin-yee; Johnson, R.K.; Sherwood, R.J.
1994-11-15
3D surface imaging refers to methods that generate a 3D surface representation of objects of a scene under viewing. Laser-based 3D surface imaging systems are commonly used in manufacturing, robotics and biomedical research. Although laser-based systems provide satisfactory solutions for most applications, there are situations where non laser-based approaches are preferred. The issues that make alternative methods sometimes more attractive are: (1) real-time data capturing, (2) eye-safety, (3) portability, and (4) work distance. The focus of this presentation is on generating a 3D surface from multiple 2D projected images using CCD cameras, without a laser light source. Two methods are presented: stereo vision and depth-from-focus. Their applications are described.
3-D Flyover Visualization of Veil Nebula
This 3-D visualization flies across a small portion of the Veil Nebula as photographed by the Hubble Space Telescope. This region is a small part of a huge expanding remnant from a star that explod...
Future Engineers 3-D Print Timelapse
NASA Challenges K-12 students to create a model of a container for space using 3-D modeling software. Astronauts need containers of all kinds - from advanced containers that can study fruit flies t...
Modeling Cellular Processes in 3-D
Mogilner, Alex; Odde, David
2011-01-01
Summary Recent advances in photonic imaging and fluorescent protein technology offer unprecedented views of molecular space-time dynamics in living cells. At the same time, advances in computing hardware and software enable modeling of ever more complex systems, from global climate to cell division. As modeling and experiment become more closely integrated, we must address the issue of modeling cellular processes in 3-D. Here, we highlight recent advances related to 3-D modeling in cell biology. While some processes require full 3-D analysis, we suggest that others are more naturally described in 2-D or 1-D. Keeping the dimensionality as low as possible reduces computational time and makes models more intuitively comprehensible; however, the ability to test full 3-D models will build greater confidence in models generally and remains an important emerging area of cell biological modeling. PMID:22036197
3D goes digital: from stereoscopy to modern 3D imaging techniques
NASA Astrophysics Data System (ADS)
Kerwien, N.
2014-11-01
In the 19th century, English physicist Charles Wheatstone discovered stereopsis, the basis for 3D perception. His construction of the first stereoscope established the foundation for stereoscopic 3D imaging. Since then, many optical instruments were influenced by these basic ideas. In recent decades, the advent of digital technologies revolutionized 3D imaging. Powerful readily available sensors and displays combined with efficient pre- or post-processing enable new methods for 3D imaging and applications. This paper draws an arc from basic concepts of 3D imaging to modern digital implementations, highlighting instructive examples from its 175 years of history.
Motif3D: Relating protein sequence motifs to 3D structure.
Gaulton, Anna; Attwood, Teresa K
2003-07-01
Motif3D is a web-based protein structure viewer designed to allow sequence motifs, and in particular those contained in the fingerprints of the PRINTS database, to be visualised on three-dimensional (3D) structures. Additional functionality is provided for the rhodopsin-like G protein-coupled receptors, enabling fingerprint motifs of any of the receptors in this family to be mapped onto the single structure available, that of bovine rhodopsin. Motif3D can be used via the web interface available at: http://www.bioinf.man.ac.uk/dbbrowser/motif3d/motif3d.html.
Assessing 3d Photogrammetry Techniques in Craniometrics
NASA Astrophysics Data System (ADS)
Moshobane, M. C.; de Bruyn, P. J. N.; Bester, M. N.
2016-06-01
Morphometrics (the measurement of morphological features) has been revolutionized by the creation of new techniques to study how organismal shape co-varies with several factors such as ecophenotypy. Ecophenotypy refers to the divergence of phenotypes due to developmental changes induced by local environmental conditions, producing distinct ecophenotypes. None of the techniques hitherto utilized could explicitly address organismal shape in a complete biological form, i.e. three-dimensionally. This study investigates the use of the commercial software, Photomodeler Scanner® (PMSc®) three-dimensional (3D) modelling software to produce accurate and high-resolution 3D models. Henceforth, the modelling of Subantarctic fur seal (Arctocephalus tropicalis) and Antarctic fur seal (Arctocephalus gazella) skulls which could allow for 3D measurements. Using this method, sixteen accurate 3D skull models were produced and five metrics were determined. The 3D linear measurements were compared to measurements taken manually with a digital caliper. In addition, repetitive measurements were recorded by varying researchers to determine repeatability. To allow for comparison straight line measurements were taken with the software, assuming that close accord with all manually measured features would illustrate the model's accurate replication of reality. Measurements were not significantly different demonstrating that realistic 3D skull models can be successfully produced to provide a consistent basis for craniometrics, with the additional benefit of allowing non-linear measurements if required.
Exploring interaction with 3D volumetric displays
NASA Astrophysics Data System (ADS)
Grossman, Tovi; Wigdor, Daniel; Balakrishnan, Ravin
2005-03-01
Volumetric displays generate true volumetric 3D images by actually illuminating points in 3D space. As a result, viewing their contents is similar to viewing physical objects in the real world. These displays provide a 360 degree field of view, and do not require the user to wear hardware such as shutter glasses or head-trackers. These properties make them a promising alternative to traditional display systems for viewing imagery in 3D. Because these displays have only recently been made available commercially (e.g., www.actuality-systems.com), their current use tends to be limited to non-interactive output-only display devices. To take full advantage of the unique features of these displays, however, it would be desirable if the 3D data being displayed could be directly interacted with and manipulated. We investigate interaction techniques for volumetric display interfaces, through the development of an interactive 3D geometric model building application. While this application area itself presents many interesting challenges, our focus is on the interaction techniques that are likely generalizable to interactive applications for other domains. We explore a very direct style of interaction where the user interacts with the virtual data using direct finger manipulations on and around the enclosure surrounding the displayed 3D volumetric image.
Modelling of 3D fractured geological systems - technique and application
NASA Astrophysics Data System (ADS)
Cacace, M.; Scheck-Wenderoth, M.; Cherubini, Y.; Kaiser, B. O.; Bloecher, G.
2011-12-01
topics including CO2 storage in deep saline aquifers, shale gas extraction and geothermal heat recovery. The main advantage is that dipping structures can be integrated into a 3D body representing the porous media and the interaction between the discrete flow paths through and across faults and fractures and within the rock matrix can be correctly simulated. In addition the complete workflow is captured by open-source software.
Recording stereoscopic 3D neurosurgery with a head-mounted 3D camera system.
Lee, Brian; Chen, Brian R; Chen, Beverly B; Lu, James Y; Giannotta, Steven L
2015-06-01
Stereoscopic three-dimensional (3D) imaging can present more information to the viewer and further enhance the learning experience over traditional two-dimensional (2D) video. Most 3D surgical videos are recorded from the operating microscope and only feature the crux, or the most important part of the surgery, leaving out other crucial parts of surgery including the opening, approach, and closing of the surgical site. In addition, many other surgeries including complex spine, trauma, and intensive care unit procedures are also rarely recorded. We describe and share our experience with a commercially available head-mounted stereoscopic 3D camera system to obtain stereoscopic 3D recordings of these seldom recorded aspects of neurosurgery. The strengths and limitations of using the GoPro(®) 3D system as a head-mounted stereoscopic 3D camera system in the operating room are reviewed in detail. Over the past several years, we have recorded in stereoscopic 3D over 50 cranial and spinal surgeries and created a library for education purposes. We have found the head-mounted stereoscopic 3D camera system to be a valuable asset to supplement 3D footage from a 3D microscope. We expect that these comprehensive 3D surgical videos will become an important facet of resident education and ultimately lead to improved patient care.
3D Numerical simulations of oblique subduction
NASA Astrophysics Data System (ADS)
Malatesta, C.; Gerya, T.; Scambelluri, M.; Crispini, L.; Federico, L.; Capponi, G.
2012-04-01
In the past 2D numerical studies (e.g. Gerya et al., 2002; Gorczyk et al., 2007; Malatesta et al., 2012) provided evidence that during intraoceanic subduction a serpentinite channel forms above the downgoing plate. This channel forms as a result of hydration of the mantle wedge by uprising slab-fluids. Rocks buried at high depths are finally exhumed within this buoyant low-viscosity medium. Convergence rate in these 2D models was described by a trench-normal component of velocity. Several present and past subduction zones worldwide are however driven by oblique convergence between the plates, where trench-normal motion of the subducting slab is coupled with trench-parallel displacement of the plates. Can the exhumation mechanism and the exhumation rates of high-pressure rocks be affected by the shear component of subduction? And how uprise of these rocks can vary along the plate margin? We tried to address these questions performing 3D numerical models that simulate an intraoceanic oblique subduction. The models are based on thermo-mechanical equations that are solved with finite differences method and marker-in-cell techniques combined with multigrid approach (Gerya, 2010). In most of the models a narrow oceanic basin (500 km-wide) surrounded by continental margins is depicted. The basin is floored by either layered or heterogeneous oceanic lithosphere with gabbro as discrete bodies in serpentinized peridotite and a basaltic layer on the top. A weak zone in the mantle is prescribed to control the location of subduction initiation and therefore the plate margins geometry. Finally, addition of a third dimension in the simulations allowed us to test the role of different plate margin geometries on oblique subduction dynamics. In particular in each model we modified the dip angle of the weak zone and its "lateral" geometry (e.g. continuous, segmented). We consider "continuous" weak zones either parallel or increasingly moving away from the continental margins
Gould, Francois D. H.
2014-01-01
Improvements in three-dimensional imaging technologies have renewed interest in the study of functional and ecological morphology. Quantitative approaches to shape analysis are used increasingly to study form-function relationships. These methods are computationally intensive, technically demanding, and time-consuming, which may limit sampling potential. There have been few side-by-side comparisons of the effectiveness of such approaches relative to more traditional analyses using linear measurements and ratios. Morphological variation in the distal femur of mammals has been shown to reflect differences in locomotor modes across clades. Thus I tested whether a geometric morphometric analysis of surface shape was superior to a multivariate analysis of ratios for describing ecomorphological patterns in distal femoral variation. A sample of 164 mammalian specimens from 44 genera was assembled. Each genus was assigned to one of six locomotor categories. The same hypotheses were tested using two methods. Six linear measurements of the distal femur were taken with calipers, from which four ratios were calculated. A 3D model was generated with a laser scanner, and analyzed using three dimensional geometric morphometrics. Locomotor category significantly predicted variation in distal femoral morphology in both analyses. Effect size was larger in the geometric morphometric analysis than in the analysis of ratios. Ordination reveals a similar pattern with arboreal and cursorial taxa as extremes on a continuum of morphologies in both analyses. Discriminant functions calculated from the geometric morphometric analysis were more accurate than those calculated from ratios. Both analysis of ratios and geometric morphometric surface analysis reveal similar, biologically meaningful relationships between distal femoral shape and locomotor mode. The functional signal from the morphology is slightly higher in the geometric morphometric analysis. The practical costs of conducting these
Self assembled structures for 3D integration
NASA Astrophysics Data System (ADS)
Rao, Madhav
Three dimensional (3D) micro-scale structures attached to a silicon substrate have various applications in microelectronics. However, formation of 3D structures using conventional micro-fabrication techniques are not efficient and require precise control of processing parameters. Self assembly is a method for creating 3D structures that takes advantage of surface area minimization phenomena. Solder based self assembly (SBSA), the subject of this dissertation, uses solder as a facilitator in the formation of 3D structures from 2D patterns. Etching a sacrificial layer underneath a portion of the 2D pattern allows the solder reflow step to pull those areas out of the substrate plane resulting in a folded 3D structure. Initial studies using the SBSA method demonstrated low yields in the formation of five different polyhedra. The failures in folding were primarily attributed to nonuniform solder deposition on the underlying metal pads. The dip soldering method was analyzed and subsequently refined. A modified dip soldering process provided improved yield among the polyhedra. Solder bridging referred as joining of solder deposited on different metal patterns in an entity influenced the folding mechanism. In general, design parameters such as small gap-spacings and thick metal pads were found to favor solder bridging for all patterns studied. Two types of soldering: face and edge soldering were analyzed. Face soldering refers to the application of solder on the entire metal face. Edge soldering indicates application of solder only on the edges of the metal face. Mechanical grinding showed that face soldered SBSA structures were void free and robust in nature. In addition, the face soldered 3D structures provide a consistent heat resistant solder standoff height that serve as attachments in the integration of dissimilar electronic technologies. Face soldered 3D structures were developed on the underlying conducting channel to determine the thermo-electric reliability of
PLOT3D Export Tool for Tecplot
NASA Technical Reports Server (NTRS)
Alter, Stephen
2010-01-01
The PLOT3D export tool for Tecplot solves the problem of modified data being impossible to output for use by another computational science solver. The PLOT3D Exporter add-on enables the use of the most commonly available visualization tools to engineers for output of a standard format. The exportation of PLOT3D data from Tecplot has far reaching effects because it allows for grid and solution manipulation within a graphical user interface (GUI) that is easily customized with macro language-based and user-developed GUIs. The add-on also enables the use of Tecplot as an interpolation tool for solution conversion between different grids of different types. This one add-on enhances the functionality of Tecplot so significantly, it offers the ability to incorporate Tecplot into a general suite of tools for computational science applications as a 3D graphics engine for visualization of all data. Within the PLOT3D Export Add-on are several functions that enhance the operations and effectiveness of the add-on. Unlike Tecplot output functions, the PLOT3D Export Add-on enables the use of the zone selection dialog in Tecplot to choose which zones are to be written by offering three distinct options - output of active, inactive, or all zones (grid blocks). As the user modifies the zones to output with the zone selection dialog, the zones to be written are similarly updated. This enables the use of Tecplot to create multiple configurations of a geometry being analyzed. For example, if an aircraft is loaded with multiple deflections of flaps, by activating and deactivating different zones for a specific flap setting, new specific configurations of that aircraft can be easily generated by only writing out specific zones. Thus, if ten flap settings are loaded into Tecplot, the PLOT3D Export software can output ten different configurations, one for each flap setting.
A microfluidic device for 2D to 3D and 3D to 3D cell navigation
NASA Astrophysics Data System (ADS)
Shamloo, Amir; Amirifar, Leyla
2016-01-01
Microfluidic devices have received wide attention and shown great potential in the field of tissue engineering and regenerative medicine. Investigating cell response to various stimulations is much more accurate and comprehensive with the aid of microfluidic devices. In this study, we introduced a microfluidic device by which the matrix density as a mechanical property and the concentration profile of a biochemical factor as a chemical property could be altered. Our microfluidic device has a cell tank and a cell culture chamber to mimic both 2D to 3D and 3D to 3D migration of three types of cells. Fluid shear stress is negligible on the cells and a stable concentration gradient can be obtained by diffusion. The device was designed by a numerical simulation so that the uniformity of the concentration gradients throughout the cell culture chamber was obtained. Adult neural cells were cultured within this device and they showed different branching and axonal navigation phenotypes within varying nerve growth factor (NGF) concentration profiles. Neural stem cells were also cultured within varying collagen matrix densities while exposed to NGF concentrations and they experienced 3D to 3D collective migration. By generating vascular endothelial growth factor concentration gradients, adult human dermal microvascular endothelial cells also migrated in a 2D to 3D manner and formed a stable lumen within a specific collagen matrix density. It was observed that a minimum absolute concentration and concentration gradient were required to stimulate migration of all types of the cells. This device has the advantage of changing multiple parameters simultaneously and is expected to have wide applicability in cell studies.
Guo, Hanqi; Phillips, Carolyn L; Peterka, Tom; Karpeyev, Dmitry; Glatz, Andreas
2016-01-01
We propose a method for the vortex extraction and tracking of superconducting magnetic flux vortices for both structured and unstructured mesh data. In the Ginzburg-Landau theory, magnetic flux vortices are well-defined features in a complex-valued order parameter field, and their dynamics determine electromagnetic properties in type-II superconductors. Our method represents each vortex line (a 1D curve embedded in 3D space) as a connected graph extracted from the discretized field in both space and time. For a time-varying discrete dataset, our vortex extraction and tracking method is as accurate as the data discretization. We then apply 3D visualization and 2D event diagrams to the extraction and tracking results to help scientists understand vortex dynamics and macroscale superconductor behavior in greater detail than previously possible.
RAG-3D: A search tool for RNA 3D substructures
Zahran, Mai; Sevim Bayrak, Cigdem; Elmetwaly, Shereef; Schlick, Tamar
2015-08-24
In this study, to address many challenges in RNA structure/function prediction, the characterization of RNA's modular architectural units is required. Using the RNA-As-Graphs (RAG) database, we have previously explored the existence of secondary structure (2D) submotifs within larger RNA structures. Here we present RAG-3D—a dataset of RNA tertiary (3D) structures and substructures plus a web-based search tool—designed to exploit graph representations of RNAs for the goal of searching for similar 3D structural fragments. The objects in RAG-3D consist of 3D structures translated into 3D graphs, cataloged based on the connectivity between their secondary structure elements. Each graph is additionally describedmore » in terms of its subgraph building blocks. The RAG-3D search tool then compares a query RNA 3D structure to those in the database to obtain structurally similar structures and substructures. This comparison reveals conserved 3D RNA features and thus may suggest functional connections. Though RNA search programs based on similarity in sequence, 2D, and/or 3D structural elements are available, our graph-based search tool may be advantageous for illuminating similarities that are not obvious; using motifs rather than sequence space also reduces search times considerably. Ultimately, such substructuring could be useful for RNA 3D structure prediction, structure/function inference and inverse folding.« less
RAG-3D: A search tool for RNA 3D substructures
Zahran, Mai; Sevim Bayrak, Cigdem; Elmetwaly, Shereef; Schlick, Tamar
2015-08-24
In this study, to address many challenges in RNA structure/function prediction, the characterization of RNA's modular architectural units is required. Using the RNA-As-Graphs (RAG) database, we have previously explored the existence of secondary structure (2D) submotifs within larger RNA structures. Here we present RAG-3D—a dataset of RNA tertiary (3D) structures and substructures plus a web-based search tool—designed to exploit graph representations of RNAs for the goal of searching for similar 3D structural fragments. The objects in RAG-3D consist of 3D structures translated into 3D graphs, cataloged based on the connectivity between their secondary structure elements. Each graph is additionally described in terms of its subgraph building blocks. The RAG-3D search tool then compares a query RNA 3D structure to those in the database to obtain structurally similar structures and substructures. This comparison reveals conserved 3D RNA features and thus may suggest functional connections. Though RNA search programs based on similarity in sequence, 2D, and/or 3D structural elements are available, our graph-based search tool may be advantageous for illuminating similarities that are not obvious; using motifs rather than sequence space also reduces search times considerably. Ultimately, such substructuring could be useful for RNA 3D structure prediction, structure/function inference and inverse folding.
RAG-3D: a search tool for RNA 3D substructures
Zahran, Mai; Sevim Bayrak, Cigdem; Elmetwaly, Shereef; Schlick, Tamar
2015-01-01
To address many challenges in RNA structure/function prediction, the characterization of RNA's modular architectural units is required. Using the RNA-As-Graphs (RAG) database, we have previously explored the existence of secondary structure (2D) submotifs within larger RNA structures. Here we present RAG-3D—a dataset of RNA tertiary (3D) structures and substructures plus a web-based search tool—designed to exploit graph representations of RNAs for the goal of searching for similar 3D structural fragments. The objects in RAG-3D consist of 3D structures translated into 3D graphs, cataloged based on the connectivity between their secondary structure elements. Each graph is additionally described in terms of its subgraph building blocks. The RAG-3D search tool then compares a query RNA 3D structure to those in the database to obtain structurally similar structures and substructures. This comparison reveals conserved 3D RNA features and thus may suggest functional connections. Though RNA search programs based on similarity in sequence, 2D, and/or 3D structural elements are available, our graph-based search tool may be advantageous for illuminating similarities that are not obvious; using motifs rather than sequence space also reduces search times considerably. Ultimately, such substructuring could be useful for RNA 3D structure prediction, structure/function inference and inverse folding. PMID:26304547
ICER-3D Hyperspectral Image Compression Software
NASA Technical Reports Server (NTRS)
Xie, Hua; Kiely, Aaron; Klimesh, matthew; Aranki, Nazeeh
2010-01-01
Software has been developed to implement the ICER-3D algorithm. ICER-3D effects progressive, three-dimensional (3D), wavelet-based compression of hyperspectral images. If a compressed data stream is truncated, the progressive nature of the algorithm enables reconstruction of hyperspectral data at fidelity commensurate with the given data volume. The ICER-3D software is capable of providing either lossless or lossy compression, and incorporates an error-containment scheme to limit the effects of data loss during transmission. The compression algorithm, which was derived from the ICER image compression algorithm, includes wavelet-transform, context-modeling, and entropy coding subalgorithms. The 3D wavelet decomposition structure used by ICER-3D exploits correlations in all three dimensions of sets of hyperspectral image data, while facilitating elimination of spectral ringing artifacts, using a technique summarized in "Improving 3D Wavelet-Based Compression of Spectral Images" (NPO-41381), NASA Tech Briefs, Vol. 33, No. 3 (March 2009), page 7a. Correlation is further exploited by a context-modeling subalgorithm, which exploits spectral dependencies in the wavelet-transformed hyperspectral data, using an algorithm that is summarized in "Context Modeler for Wavelet Compression of Hyperspectral Images" (NPO-43239), which follows this article. An important feature of ICER-3D is a scheme for limiting the adverse effects of loss of data during transmission. In this scheme, as in the similar scheme used by ICER, the spatial-frequency domain is partitioned into rectangular error-containment regions. In ICER-3D, the partitions extend through all the wavelength bands. The data in each partition are compressed independently of those in the other partitions, so that loss or corruption of data from any partition does not affect the other partitions. Furthermore, because compression is progressive within each partition, when data are lost, any data from that partition received
Turner, D.
1983-08-01
The T-HEMP3D (Transportable HEMP3D) computer program is a derivative of the STEALTH three-dimensional thermodynamics code developed by Science Applications, Inc., under the direction of Ron Hofmann. STEALTH, in turn, is based entirely on the original HEMP3D code written at Lawrence Livermore National Laboratory. The primary advantage STEALTH has over its predecessors is that it was designed using modern structured design techniques, with rigorous programming standards enforced. This yields two benefits. First, the code is easily changeable; this is a necessity for a physics code used for research. The second benefit is that the code is easily transportable between different types of computers. The STEALTH program was transferred to LLNL under a cooperative development agreement. Changes were made primarily in three areas: material specification, coordinate generation, and the addition of sliding surface boundary conditions. The code was renamed T-HEMP3D to avoid confusion with other versions of STEALTH. This document summarizes the input to T-HEMP3D, as used at LLNL. It does not describe the physics simulated by the program, nor the numerical techniques employed. Furthermore, it does not describe the separate job steps of coordinate generation and post-processing, including graphical display of results. (WHK)
The importance of 3D dosimetry
NASA Astrophysics Data System (ADS)
Low, Daniel
2015-01-01
Radiation therapy has been getting progressively more complex for the past 20 years. Early radiation therapy techniques needed only basic dosimetry equipment; motorized water phantoms, ionization chambers, and basic radiographic film techniques. As intensity modulated radiation therapy and image guided therapy came into widespread practice, medical physicists were challenged with developing effective and efficient dose measurement techniques. The complex 3-dimensional (3D) nature of the dose distributions that were being delivered demanded the development of more quantitative and more thorough methods for dose measurement. The quality assurance vendors developed a wide array of multidetector arrays that have been enormously useful for measuring and characterizing dose distributions, and these have been made especially useful with the advent of 3D dose calculation systems based on the array measurements, as well as measurements made using film and portal imagers. Other vendors have been providing 3D calculations based on data from the linear accelerator or the record and verify system, providing thorough evaluation of the dose but lacking quality assurance (QA) of the dose delivery process, including machine calibration. The current state of 3D dosimetry is one of a state of flux. The vendors and professional associations are trying to determine the optimal balance between thorough QA, labor efficiency, and quantitation. This balance will take some time to reach, but a necessary component will be the 3D measurement and independent calculation of delivered radiation therapy dose distributions.
3D Spray Droplet Distributions in Sneezes
NASA Astrophysics Data System (ADS)
Techet, Alexandra; Scharfman, Barry; Bourouiba, Lydia
2015-11-01
3D spray droplet clouds generated during human sneezing are investigated using the Synthetic Aperture Feature Extraction (SAFE) method, which relies on light field imaging (LFI) and synthetic aperture (SA) refocusing computational photographic techniques. An array of nine high-speed cameras are used to image sneeze droplets and tracked the droplets in 3D space and time (3D + T). An additional high-speed camera is utilized to track the motion of the head during sneezing. In the SAFE method, the raw images recorded by each camera in the array are preprocessed and binarized, simplifying post processing after image refocusing and enabling the extraction of feature sizes and positions in 3D + T. These binary images are refocused using either additive or multiplicative methods, combined with thresholding. Sneeze droplet centroids, radii, distributions and trajectories are determined and compared with existing data. The reconstructed 3D droplet centroids and radii enable a more complete understanding of the physical extent and fluid dynamics of sneeze ejecta. These measurements are important for understanding the infectious disease transmission potential of sneezes in various indoor environments.
Extra dimensions: 3D in PDF documentation
Graf, Norman A.
2011-01-11
Experimental science is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. By providing support for scripting and animation, temporal data can also be easily distributed to a wide, non-technical audience. We discuss how the field of radiation imaging could benefit from incorporating full 3D information about not only the detectors, but also the results of the experimental analyses, in its electronic publications. In this article, we present examples drawn from high-energy physics, mathematics and molecular biology which take advantage of this functionality. Furthermore, we demonstrate how 3D detector elements can be documented, using either CAD drawings or other sources such as GEANT visualizations as input.
3D dynamic roadmapping for abdominal catheterizations.
Bender, Frederik; Groher, Martin; Khamene, Ali; Wein, Wolfgang; Heibel, Tim Hauke; Navab, Nassir
2008-01-01
Despite rapid advances in interventional imaging, the navigation of a guide wire through abdominal vasculature remains, not only for novice radiologists, a difficult task. Since this navigation is mostly based on 2D fluoroscopic image sequences from one view, the process is slowed down significantly due to missing depth information and patient motion. We propose a novel approach for 3D dynamic roadmapping in deformable regions by predicting the location of the guide wire tip in a 3D vessel model from the tip's 2D location, respiratory motion analysis, and view geometry. In a first step, the method compensates for the apparent respiratory motion in 2D space before backprojecting the 2D guide wire tip into three dimensional space, using a given projection matrix. To countervail the error connected to the projection parameters and the motion compensation, as well as the ambiguity caused by vessel deformation, we establish a statistical framework, which computes a reliable estimate of the guide wire tip location within the 3D vessel model. With this 2D-to-3D transfer, the navigation can be performed from arbitrary viewing angles, disconnected from the static perspective view of the fluoroscopic sequence. Tests on a realistic breathing phantom and on synthetic data with a known ground truth clearly reveal the superiority of our approach compared to naive methods for 3D roadmapping. The concepts and information presented in this paper are based on research and are not commercially available. PMID:18982662
3D bioprinting for engineering complex tissues.
Mandrycky, Christian; Wang, Zongjie; Kim, Keekyoung; Kim, Deok-Ho
2016-01-01
Bioprinting is a 3D fabrication technology used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. While still in its early stages, bioprinting strategies have demonstrated their potential use in regenerative medicine to generate a variety of transplantable tissues, including skin, cartilage, and bone. However, current bioprinting approaches still have technical challenges in terms of high-resolution cell deposition, controlled cell distributions, vascularization, and innervation within complex 3D tissues. While no one-size-fits-all approach to bioprinting has emerged, it remains an on-demand, versatile fabrication technique that may address the growing organ shortage as well as provide a high-throughput method for cell patterning at the micrometer scale for broad biomedical engineering applications. In this review, we introduce the basic principles, materials, integration strategies and applications of bioprinting. We also discuss the recent developments, current challenges and future prospects of 3D bioprinting for engineering complex tissues. Combined with recent advances in human pluripotent stem cell technologies, 3D-bioprinted tissue models could serve as an enabling platform for high-throughput predictive drug screening and more effective regenerative therapies.
Shim3d Helmholtz Solution Package
2009-01-29
This suite of codes solves the Helmholtz Equation for the steady-state propagation of single-frequency electromagnetic radiation in an arbitrary 2D or 3D dielectric medium. Materials can be either transparent or absorptive (including metals) and are described entirely by their shape and complex dielectric constant. Dielectric boundaries are assumed to always fall on grid boundaries and the material within a single grid cell is considered to be uniform. Input to the problem is in the formmore » of a Dirichlet boundary condition on a single boundary, and may be either analytic (Gaussian) in shape, or a mode shape computed using a separate code (such as the included eigenmode solver vwave20), and written to a file. Solution is via the finite difference method using Jacobi iteration for 3D problems or direct matrix inversion for 2D problems. Note that 3D problems that include metals will require different iteration parameters than described in the above reference. For structures with curved boundaries not easily modeled on a rectangular grid, the auxillary codes helmholtz11(2D), helm3d (semivectoral), and helmv3d (full vectoral) are provided. For these codes the finite difference equations are specified on a topological regular triangular grid and solved using Jacobi iteration or direct matrix inversion as before. An automatic grid generator is supplied.« less
Full-color holographic 3D printer
NASA Astrophysics Data System (ADS)
Takano, Masami; Shigeta, Hiroaki; Nishihara, Takashi; Yamaguchi, Masahiro; Takahashi, Susumu; Ohyama, Nagaaki; Kobayashi, Akihiko; Iwata, Fujio
2003-05-01
A holographic 3D printer is a system that produces a direct hologram with full-parallax information using the 3-dimensional data of a subject from a computer. In this paper, we present a proposal for the reproduction of full-color images with the holographic 3D printer. In order to realize the 3-dimensional color image, we selected the 3 laser wavelength colors of red (λ=633nm), green (λ=533nm), and blue (λ=442nm), and we built a one-step optical system using a projection system and a liquid crystal display. The 3-dimensional color image is obtained by synthesizing in a 2D array the multiple exposure with these 3 wavelengths made on each 250mm elementary hologram, and moving recording medium on a x-y stage. For the natural color reproduction in the holographic 3D printer, we take the approach of the digital processing technique based on the color management technology. The matching between the input and output colors is performed by investigating first, the relation between the gray level transmittance of the LCD and the diffraction efficiency of the hologram and second, by measuring the color displayed by the hologram to establish a correlation. In our first experimental results a non-linear functional relation for single and multiple exposure of the three components were found. These results are the first step in the realization of a natural color 3D image produced by the holographic color 3D printer.
DYNA3D Code Practices and Developments
Lin, L.; Zywicz, E.; Raboin, P.
2000-04-21
DYNA3D is an explicit, finite element code developed to solve high rate dynamic simulations for problems of interest to the engineering mechanics community. The DYNA3D code has been under continuous development since 1976[1] by the Methods Development Group in the Mechanical Engineering Department of Lawrence Livermore National Laboratory. The pace of code development activities has substantially increased in the past five years, growing from one to between four and six code developers. This has necessitated the use of software tools such as CVS (Concurrent Versions System) to help manage multiple version updates. While on-line documentation with an Adobe PDF manual helps to communicate software developments, periodically a summary document describing recent changes and improvements in DYNA3D software is needed. The first part of this report describes issues surrounding software versions and source control. The remainder of this report details the major capability improvements since the last publicly released version of DYNA3D in 1996. Not included here are the many hundreds of bug corrections and minor enhancements, nor the development in DYNA3D between the manual release in 1993[2] and the public code release in 1996.
BEAMS3D Neutral Beam Injection Model
NASA Astrophysics Data System (ADS)
McMillan, Matthew; Lazerson, Samuel A.
2014-09-01
With the advent of applied 3D fields in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous slowing down, and pitch angle scattering are modeled with the ADAS atomic physics database. Elementary benchmark calculations are presented to verify the collisionless particle orbits, NBI model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields. Notice: this manuscript has been authored by Princeton University under Contract Number DE-AC02-09CH11466 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.
Lifting Object Detection Datasets into 3D.
Carreira, Joao; Vicente, Sara; Agapito, Lourdes; Batista, Jorge
2016-07-01
While data has certainly taken the center stage in computer vision in recent years, it can still be difficult to obtain in certain scenarios. In particular, acquiring ground truth 3D shapes of objects pictured in 2D images remains a challenging feat and this has hampered progress in recognition-based object reconstruction from a single image. Here we propose to bypass previous solutions such as 3D scanning or manual design, that scale poorly, and instead populate object category detection datasets semi-automatically with dense, per-object 3D reconstructions, bootstrapped from:(i) class labels, (ii) ground truth figure-ground segmentations and (iii) a small set of keypoint annotations. Our proposed algorithm first estimates camera viewpoint using rigid structure-from-motion and then reconstructs object shapes by optimizing over visual hull proposals guided by loose within-class shape similarity assumptions. The visual hull sampling process attempts to intersect an object's projection cone with the cones of minimal subsets of other similar objects among those pictured from certain vantage points. We show that our method is able to produce convincing per-object 3D reconstructions and to accurately estimate cameras viewpoints on one of the most challenging existing object-category detection datasets, PASCAL VOC. We hope that our results will re-stimulate interest on joint object recognition and 3D reconstruction from a single image. PMID:27295458
Magnetic Properties of 3D Printed Toroids
NASA Astrophysics Data System (ADS)
Bollig, Lindsey; Otto, Austin; Hilpisch, Peter; Mowry, Greg; Nelson-Cheeseman, Brittany; Renewable Energy; Alternatives Lab (REAL) Team
Transformers are ubiquitous in electronics today. Although toroidal geometries perform most efficiently, transformers are traditionally made with rectangular cross-sections due to the lower manufacturing costs. Additive manufacturing techniques (3D printing) can easily achieve toroidal geometries by building up a part through a series of 2D layers. To get strong magnetic properties in a 3D printed transformer, a composite filament is used containing Fe dispersed in a polymer matrix. How the resulting 3D printed toroid responds to a magnetic field depends on two structural factors of the printed 2D layers: fill factor (planar density) and fill pattern. In this work, we investigate how the fill factor and fill pattern affect the magnetic properties of 3D printed toroids. The magnetic properties of the printed toroids are measured by a custom circuit that produces a hysteresis loop for each toroid. Toroids with various fill factors and fill patterns are compared to determine how these two factors can affect the magnetic field the toroid can produce. These 3D printed toroids can be used for numerous applications in order to increase the efficiency of transformers by making it possible for manufacturers to make a toroidal geometry.
3D bioprinting for engineering complex tissues.
Mandrycky, Christian; Wang, Zongjie; Kim, Keekyoung; Kim, Deok-Ho
2016-01-01
Bioprinting is a 3D fabrication technology used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. While still in its early stages, bioprinting strategies have demonstrated their potential use in regenerative medicine to generate a variety of transplantable tissues, including skin, cartilage, and bone. However, current bioprinting approaches still have technical challenges in terms of high-resolution cell deposition, controlled cell distributions, vascularization, and innervation within complex 3D tissues. While no one-size-fits-all approach to bioprinting has emerged, it remains an on-demand, versatile fabrication technique that may address the growing organ shortage as well as provide a high-throughput method for cell patterning at the micrometer scale for broad biomedical engineering applications. In this review, we introduce the basic principles, materials, integration strategies and applications of bioprinting. We also discuss the recent developments, current challenges and future prospects of 3D bioprinting for engineering complex tissues. Combined with recent advances in human pluripotent stem cell technologies, 3D-bioprinted tissue models could serve as an enabling platform for high-throughput predictive drug screening and more effective regenerative therapies. PMID:26724184
Zuppinger, Christian
2016-07-01
This review discusses historical milestones, recent developments and challenges in the area of 3D culture models with cardiovascular cell types. Expectations in this area have been raised in recent years, but more relevant in vitro research, more accurate drug testing results, reliable disease models and insights leading to bioartificial organs are expected from the transition to 3D cell culture. However, the construction of organ-like cardiac 3D models currently remains a difficult challenge. The heart consists of highly differentiated cells in an intricate arrangement.Furthermore, electrical “wiring”, a vascular system and multiple cell types act in concert to respond to the rapidly changing demands of the body. Although cardiovascular 3D culture models have been predominantly developed for regenerative medicine in the past, their use in drug screening and for disease models has become more popular recently. Many sophisticated 3D culture models are currently being developed in this dynamic area of life science. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
Miniaturized 3D microscope imaging system
NASA Astrophysics Data System (ADS)
Lan, Yung-Sung; Chang, Chir-Weei; Sung, Hsin-Yueh; Wang, Yen-Chang; Chang, Cheng-Yi
2015-05-01
We designed and assembled a portable 3-D miniature microscopic image system with the size of 35x35x105 mm3 . By integrating a microlens array (MLA) into the optical train of a handheld microscope, the biological specimen's image will be captured for ease of use in a single shot. With the light field raw data and program, the focal plane can be changed digitally and the 3-D image can be reconstructed after the image was taken. To localize an object in a 3-D volume, an automated data analysis algorithm to precisely distinguish profundity position is needed. The ability to create focal stacks from a single image allows moving or specimens to be recorded. Applying light field microscope algorithm to these focal stacks, a set of cross sections will be produced, which can be visualized using 3-D rendering. Furthermore, we have developed a series of design rules in order to enhance the pixel using efficiency and reduce the crosstalk between each microlens for obtain good image quality. In this paper, we demonstrate a handheld light field microscope (HLFM) to distinguish two different color fluorescence particles separated by a cover glass in a 600um range, show its focal stacks, and 3-D position.
Extra dimensions: 3D in PDF documentation
Graf, Norman A.
2011-01-11
Experimental science is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universalmore » 3D (U3D) file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. By providing support for scripting and animation, temporal data can also be easily distributed to a wide, non-technical audience. We discuss how the field of radiation imaging could benefit from incorporating full 3D information about not only the detectors, but also the results of the experimental analyses, in its electronic publications. In this article, we present examples drawn from high-energy physics, mathematics and molecular biology which take advantage of this functionality. Furthermore, we demonstrate how 3D detector elements can be documented, using either CAD drawings or other sources such as GEANT visualizations as input.« less
3D optical measuring technologies and systems
NASA Astrophysics Data System (ADS)
Chugui, Yuri V.
2005-02-01
The results of the R & D activity of TDI SIE SB RAS in the field of the 3D optical measuring technologies and systems for noncontact 3D optical dimensional inspection applied to atomic and railway industry safety problems are presented. This activity includes investigations of diffraction phenomena on some 3D objects, using the original constructive calculation method. The efficient algorithms for precise determining the transverse and longitudinal sizes of 3D objects of constant thickness by diffraction method, peculiarities on formation of the shadow and images of the typical elements of the extended objects were suggested. Ensuring the safety of nuclear reactors and running trains as well as their high exploitation reliability requires a 100% noncontact precise inspection of geometrical parameters of their components. To solve this problem we have developed methods and produced the technical vision measuring systems LMM, CONTROL, PROFIL, and technologies for noncontact 3D dimensional inspection of grid spacers and fuel elements for the nuclear reactor VVER-1000 and VVER-440, as well as automatic laser diagnostic COMPLEX for noncontact inspection of geometric parameters of running freight car wheel pairs. The performances of these systems and the results of industrial testing are presented and discussed. The created devices are in pilot operation at Atomic and Railway Companies.
Hur, J.; Chun, Y.D.; Lee, J.; Hyun, D.S.
1998-09-01
The distribution of radial force density in brushless permanent magnet DC motor is not uniform in axial direction. The analysis of radial force density has to consider the 3-D shape of teeth and overhand, because the radial force density causes vibration and acts on the surface of teeth inconstantly. For the analysis, a new 3-D equivalent magnetic circuit network method is used to account the rotor movement without remesh. The radial force density is calculated and analyzed by Maxwell stress tensor and discrete Fourier transform (DFT) respectively. The results of 3-D equivalent magnetic circuit method have been compared with the results of 3-D FEM.
Performance prediction for 3D filtering of multichannel images
NASA Astrophysics Data System (ADS)
Rubel, Oleksii; Kozhemiakin, Ruslan A.; Abramov, Sergey K.; Lukin, Vladimir V.; Vozel, Benoit; Chehdi, Kacem
2015-10-01
Performance of denoising based on discrete cosine transform applied to multichannel remote sensing images corrupted by additive white Gaussian noise is analyzed. Images obtained by satellite Earth Observing-1 (EO-1) mission using hyperspectral imager instrument (Hyperion) that have high input SNR are taken as test images. Denoising performance is characterized by improvement of PSNR. For hard-thresholding 3D DCT-based denoising, simple statistics (probabilities to be less than a certain threshold) are used to predict denoising efficiency using curves fitted into scatterplots. It is shown that the obtained curves (approximations) provide prediction of denoising efficiency with high accuracy. Analysis is carried out for different numbers of channels processed jointly. Universality of prediction for different number of channels is proven.
Diffusive smoothing of 3D segmented medical data
Patané, Giuseppe
2014-01-01
This paper proposes an accurate, computationally efficient, and spectrum-free formulation of the heat diffusion smoothing on 3D shapes, represented as triangle meshes. The idea behind our approach is to apply a (r,r)-degree Padé–Chebyshev rational approximation to the solution of the heat diffusion equation. The proposed formulation is equivalent to solve r sparse, symmetric linear systems, is free of user-defined parameters, and is robust to surface discretization. We also discuss a simple criterion to select the time parameter that provides the best compromise between approximation accuracy and smoothness of the solution. Finally, our experiments on anatomical data show that the spectrum-free approach greatly reduces the computational cost and guarantees a higher approximation accuracy than previous work. PMID:26257940
Potentially singular solutions of the 3D axisymmetric Euler equations
Luo, Guo; Hou, Thomas Y.
2014-01-01
The question of finite-time blowup of the 3D incompressible Euler equations is numerically investigated in a periodic cylinder with solid boundaries. Using rotational symmetry, the equations are discretized in the (2D) meridian plane on an adaptive (moving) mesh and is integrated in time with adaptively chosen time steps. The vorticity is observed to develop a ring-singularity on the solid boundary with a growth proportional to ∼(ts − t)−2.46, where ts ∼ 0.0035056 is the estimated singularity time. A local analysis also suggests the existence of a self-similar blowup. The simulations stop at τ2 = 0.003505 at which time the vorticity amplifies by more than (3 × 108)-fold and the maximum mesh resolution exceeds (3 × 1012)2. The vorticity vector is observed to maintain four significant digits throughout the computations. PMID:25157172
Potentially singular solutions of the 3D axisymmetric Euler equations.
Luo, Guo; Hou, Thomas Y
2014-09-01
The question of finite-time blowup of the 3D incompressible Euler equations is numerically investigated in a periodic cylinder with solid boundaries. Using rotational symmetry, the equations are discretized in the (2D) meridian plane on an adaptive (moving) mesh and is integrated in time with adaptively chosen time steps. The vorticity is observed to develop a ring-singularity on the solid boundary with a growth proportional to ∼(ts - t)(-2.46), where ts ∼ 0.0035056 is the estimated singularity time. A local analysis also suggests the existence of a self-similar blowup. The simulations stop at τ(2) = 0.003505 at which time the vorticity amplifies by more than (3 × 10(8))-fold and the maximum mesh resolution exceeds (3 × 10(12))(2). The vorticity vector is observed to maintain four significant digits throughout the computations.
Refilling of carbon nanotube cartridges for 3D nanomanufacturing.
Bekarevich, Raman; Toyoda, Masami; Baba, Shuichi; Nakata, Toshihiko; Hirahara, Kaori
2016-04-01
Metal-filled carbon nanotubes (CNTs) are known to be used as pen-tip injectors for 3D manufacturing on the nanoscale. However, the CNT interior cannot accumulate enough material to fabricate complex metallic nanostructures. Therefore a method for refilling the CNT cartridge needs to be developed. The strategy for refilling of CNT cartridges is suggested in this study. Controlled growth of gold nanowires in the interior of isolated CNTs using a real-time manipulator installed in a transmission electron microscope is reported herein. The encapsulation process of discrete gold nanoparticles in the hollow spaces of open-ended multi-wall CNTs was evaluated in detail. The experimental results reveal that the serial loading of isolated gold nanoparticles allows the control of the length of the loaded nanowires with nanometer accuracy. Thermophoresis and the coalescence of gold nanoparticles are assumed to be the primary mechanisms responsible for gold loading into a CNT cartridge. PMID:26973081
3D Simulation: Microgravity Environments and Applications
NASA Technical Reports Server (NTRS)
Hunter, Steve L.; Dischinger, Charles; Estes, Samantha; Parker, Nelson C. (Technical Monitor)
2001-01-01
Most, if not all, 3-D and Virtual Reality (VR) software programs are designed for one-G gravity applications. Space environments simulations require gravity effects of one one-thousandth to one one-million of that of the Earth's surface (10(exp -3) - 10(exp -6) G), thus one must be able to generate simulations that replicate those microgravity effects upon simulated astronauts. Unfortunately, the software programs utilized by the National Aeronautical and Space Administration does not have the ability to readily neutralize the one-G gravity effect. This pre-programmed situation causes the engineer or analysis difficulty during micro-gravity simulations. Therefore, microgravity simulations require special techniques or additional code in order to apply the power of 3D graphic simulation to space related applications. This paper discusses the problem and possible solutions to allow microgravity 3-D/VR simulations to be completed successfully without program code modifications.
3D differential phase contrast microscopy
NASA Astrophysics Data System (ADS)
Chen, Michael; Tian, Lei; Waller, Laura
2016-03-01
We demonstrate three-dimensional (3D) optical phase and amplitude reconstruction based on coded source illumination using a programmable LED array. Multiple stacks of images along the optical axis are computed from recorded intensities captured by multiple images under off-axis illumination. Based on the first Born approximation, a linear differential phase contrast (DPC) model is built between 3D complex index of refraction and the intensity stacks. Therefore, 3D volume reconstruction can be achieved via a fast inversion method, without the intermediate 2D phase retrieval step. Our system employs spatially partially coherent illumination, so the transverse resolution achieves twice the NA of coherent systems, while axial resolution is also improved 2× as compared to holographic imaging.
The CIFIST 3D model atmosphere grid.
NASA Astrophysics Data System (ADS)
Ludwig, H.-G.; Caffau, E.; Steffen, M.; Freytag, B.; Bonifacio, P.; Kučinskas, A.
Grids of stellar atmosphere models and associated synthetic spectra are numerical products which have a large impact in astronomy due to their ubiquitous application in the interpretation of radiation from individual stars and stellar populations. 3D model atmospheres are now on the verge of becoming generally available for a wide range of stellar atmospheric parameters. We report on efforts to develop a grid of 3D model atmospheres for late-type stars within the CIFIST Team at Paris Observatory. The substantial demands in computational and human labor for the model production and post-processing render this apparently mundane task a challenging logistic exercise. At the moment the CIFIST grid comprises 77 3D model atmospheres with emphasis on dwarfs of solar and sub-solar metallicities. While the model production is still ongoing, first applications are already worked upon by the CIFIST Team and collaborators.
3D Printed Multimaterial Microfluidic Valve.
Keating, Steven J; Gariboldi, Maria Isabella; Patrick, William G; Sharma, Sunanda; Kong, David S; Oxman, Neri
2016-01-01
We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics.
Simnple, portable, 3-D projection routine
Wagner, J.S.
1987-04-01
A 3-D projection routine is presented for use in computer graphics applications. The routine is simple enough to be considered portable, and easily modified for special problems. There is often the need to draw three-dimensional objects on a two-dimensional plotting surface. For the object to appear realistic, perspective effects must be included that allow near objects to appear larger than distant objects. Several 3-D projection routines are commercially available, but they are proprietary, not portable, and not easily changed by the user. Most are restricted to surfaces that are functions of two variables. This makes them unsuitable for viewing physical objects such as accelerator prototypes or propagating beams. This report develops a very simple algorithm for 3-D projections; the core routine is only 39 FORTRAN lines long. It can be easily modified for special problems. Software dependent calls are confined to simple drivers that can be exchanged when different plotting software packages are used.
Ames Lab 101: 3D Metals Printer
Ott, Ryan
2014-02-13
To meet one of the biggest energy challenges of the 21st century - finding alternatives to rare-earth elements and other critical materials - scientists will need new and advanced tools. The Critical Materials Institute at the U.S. Department of Energy's Ames Laboratory has a new one: a 3D printer for metals research. 3D printing technology, which has captured the imagination of both industry and consumers, enables ideas to move quickly from the initial design phase to final form using materials including polymers, ceramics, paper and even food. But the Critical Materials Institute (CMI) will apply the advantages of the 3D printing process in a unique way: for materials discovery.
3D Printed Multimaterial Microfluidic Valve
Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri
2016-01-01
We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809
Structured light field 3D imaging.
Cai, Zewei; Liu, Xiaoli; Peng, Xiang; Yin, Yongkai; Li, Ameng; Wu, Jiachen; Gao, Bruce Z
2016-09-01
In this paper, we propose a method by means of light field imaging under structured illumination to deal with high dynamic range 3D imaging. Fringe patterns are projected onto a scene and modulated by the scene depth then a structured light field is detected using light field recording devices. The structured light field contains information about ray direction and phase-encoded depth, via which the scene depth can be estimated from different directions. The multidirectional depth estimation can achieve high dynamic 3D imaging effectively. We analyzed and derived the phase-depth mapping in the structured light field and then proposed a flexible ray-based calibration approach to determine the independent mapping coefficients for each ray. Experimental results demonstrated the validity of the proposed method to perform high-quality 3D imaging for highly and lowly reflective surfaces. PMID:27607639
3D-printed microfluidic devices.
Amin, Reza; Knowlton, Stephanie; Hart, Alexander; Yenilmez, Bekir; Ghaderinezhad, Fariba; Katebifar, Sara; Messina, Michael; Khademhosseini, Ali; Tasoglu, Savas
2016-06-20
Microfluidics is a flourishing field, enabling a wide range of biochemical and clinical applications such as cancer screening, micro-physiological system engineering, high-throughput drug testing, and point-of-care diagnostics. However, fabrication of microfluidic devices is often complicated, time consuming, and requires expensive equipment and sophisticated cleanroom facilities. Three-dimensional (3D) printing presents a promising alternative to traditional techniques such as lithography and PDMS-glass bonding, not only by enabling rapid design iterations in the development stage, but also by reducing the costs associated with institutional infrastructure, equipment installation, maintenance, and physical space. With the recent advancements in 3D printing technologies, highly complex microfluidic devices can be fabricated via single-step, rapid, and cost-effective protocols, making microfluidics more accessible to users. In this review, we discuss a broad range of approaches for the application of 3D printing technology to fabrication of micro-scale lab-on-a-chip devices.
3D Printed Multimaterial Microfluidic Valve.
Keating, Steven J; Gariboldi, Maria Isabella; Patrick, William G; Sharma, Sunanda; Kong, David S; Oxman, Neri
2016-01-01
We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809
3-D Mesh Generation Nonlinear Systems
Christon, M. A.; Dovey, D.; Stillman, D. W.; Hallquist, J. O.; Rainsberger, R. B
1994-04-07
INGRID is a general-purpose, three-dimensional mesh generator developed for use with finite element, nonlinear, structural dynamics codes. INGRID generates the large and complex input data files for DYNA3D, NIKE3D, FACET, and TOPAZ3D. One of the greatest advantages of INGRID is that virtually any shape can be described without resorting to wedge elements, tetrahedrons, triangular elements or highly distorted quadrilateral or hexahedral elements. Other capabilities available are in the areas of geometry and graphics. Exact surface equations and surface intersections considerably improve the ability to deal with accurate models, and a hidden line graphics algorithm is included which is efficient on the most complicated meshes. The primary new capability is associated with the boundary conditions, loads, and material properties required by nonlinear mechanics programs. Commands have been designed for each case to minimize user effort. This is particularly important since special processing is almost always required for each load or boundary condition.
3D holoscopic video imaging system
NASA Astrophysics Data System (ADS)
Steurer, Johannes H.; Pesch, Matthias; Hahne, Christopher
2012-03-01
Since many years, integral imaging has been discussed as a technique to overcome the limitations of standard still photography imaging systems where a three-dimensional scene is irrevocably projected onto two dimensions. With the success of 3D stereoscopic movies, a huge interest in capturing three-dimensional motion picture scenes has been generated. In this paper, we present a test bench integral imaging camera system aiming to tailor the methods of light field imaging towards capturing integral 3D motion picture content. We estimate the hardware requirements needed to generate high quality 3D holoscopic images and show a prototype camera setup that allows us to study these requirements using existing technology. The necessary steps that are involved in the calibration of the system as well as the technique of generating human readable holoscopic images from the recorded data are discussed.
3D face analysis for demographic biometrics
Tokola, Ryan A; Mikkilineni, Aravind K; Boehnen, Chris Bensing
2015-01-01
Despite being increasingly easy to acquire, 3D data is rarely used for face-based biometrics applications beyond identification. Recent work in image-based demographic biometrics has enjoyed much success, but these approaches suffer from the well-known limitations of 2D representations, particularly variations in illumination, texture, and pose, as well as a fundamental inability to describe 3D shape. This paper shows that simple 3D shape features in a face-based coordinate system are capable of representing many biometric attributes without problem-specific models or specialized domain knowledge. The same feature vector achieves impressive results for problems as diverse as age estimation, gender classification, and race classification.
3-D Finite Element Heat Transfer
1992-02-01
TOPAZ3D is a three-dimensional implicit finite element computer code for heat transfer analysis. TOPAZ3D can be used to solve for the steady-state or transient temperature field on three-dimensional geometries. Material properties may be temperature-dependent and either isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions can be specified including temperature, flux, convection, and radiation. By implementing the user subroutine feature, users can model chemical reaction kinetics and allow for any type of functionalmore » representation of boundary conditions and internal heat generation. TOPAZ3D can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in the material surrounding the enclosure. Additional features include thermal contact resistance across an interface, bulk fluids, phase change, and energy balances.« less
Ames Lab 101: 3D Metals Printer
Ott, Ryan
2016-07-12
To meet one of the biggest energy challenges of the 21st century - finding alternatives to rare-earth elements and other critical materials - scientists will need new and advanced tools. The Critical Materials Institute at the U.S. Department of Energy's Ames Laboratory has a new one: a 3D printer for metals research. 3D printing technology, which has captured the imagination of both industry and consumers, enables ideas to move quickly from the initial design phase to final form using materials including polymers, ceramics, paper and even food. But the Critical Materials Institute (CMI) will apply the advantages of the 3D printing process in a unique way: for materials discovery.
Real-time monitoring of 3D cell culture using a 3D capacitance biosensor.
Lee, Sun-Mi; Han, Nalae; Lee, Rimi; Choi, In-Hong; Park, Yong-Beom; Shin, Jeon-Soo; Yoo, Kyung-Hwa
2016-03-15
Three-dimensional (3D) cell cultures have recently received attention because they represent a more physiologically relevant environment compared to conventional two-dimensional (2D) cell cultures. However, 2D-based imaging techniques or cell sensors are insufficient for real-time monitoring of cellular behavior in 3D cell culture. Here, we report investigations conducted with a 3D capacitance cell sensor consisting of vertically aligned pairs of electrodes. When GFP-expressing human breast cancer cells (GFP-MCF-7) encapsulated in alginate hydrogel were cultured in a 3D cell culture system, cellular activities, such as cell proliferation and apoptosis at different heights, could be monitored non-invasively and in real-time by measuring the change in capacitance with the 3D capacitance sensor. Moreover, we were able to monitor cell migration of human mesenchymal stem cells (hMSCs) with our 3D capacitance sensor.
3D scene reconstruction based on 3D laser point cloud combining UAV images
NASA Astrophysics Data System (ADS)
Liu, Huiyun; Yan, Yangyang; Zhang, Xitong; Wu, Zhenzhen
2016-03-01
It is a big challenge capturing and modeling 3D information of the built environment. A number of techniques and technologies are now in use. These include GPS, and photogrammetric application and also remote sensing applications. The experiment uses multi-source data fusion technology for 3D scene reconstruction based on the principle of 3D laser scanning technology, which uses the laser point cloud data as the basis and Digital Ortho-photo Map as an auxiliary, uses 3DsMAX software as a basic tool for building three-dimensional scene reconstruction. The article includes data acquisition, data preprocessing, 3D scene construction. The results show that the 3D scene has better truthfulness, and the accuracy of the scene meet the need of 3D scene construction.
3D whiteboard: collaborative sketching with 3D-tracked smart phones
NASA Astrophysics Data System (ADS)
Lue, James; Schulze, Jürgen P.
2014-02-01
We present the results of our investigation of the feasibility of a new approach for collaborative drawing in 3D, based on Android smart phones. Our approach utilizes a number of fiduciary markers, placed in the working area where they can be seen by the smart phones' cameras, in order to estimate the pose of each phone in the room. Our prototype allows two users to draw 3D objects with their smart phones by moving their phones around in 3D space. For example, 3D lines are drawn by recording the path of the phone as it is moved around in 3D space, drawing line segments on the screen along the way. Each user can see the virtual drawing space on their smart phones' displays, as if the display was a window into this space. Besides lines, our prototype application also supports 3D geometry creation, geometry transformation operations, and it shows the location of the other user's phone.
Real-time monitoring of 3D cell culture using a 3D capacitance biosensor.
Lee, Sun-Mi; Han, Nalae; Lee, Rimi; Choi, In-Hong; Park, Yong-Beom; Shin, Jeon-Soo; Yoo, Kyung-Hwa
2016-03-15
Three-dimensional (3D) cell cultures have recently received attention because they represent a more physiologically relevant environment compared to conventional two-dimensional (2D) cell cultures. However, 2D-based imaging techniques or cell sensors are insufficient for real-time monitoring of cellular behavior in 3D cell culture. Here, we report investigations conducted with a 3D capacitance cell sensor consisting of vertically aligned pairs of electrodes. When GFP-expressing human breast cancer cells (GFP-MCF-7) encapsulated in alginate hydrogel were cultured in a 3D cell culture system, cellular activities, such as cell proliferation and apoptosis at different heights, could be monitored non-invasively and in real-time by measuring the change in capacitance with the 3D capacitance sensor. Moreover, we were able to monitor cell migration of human mesenchymal stem cells (hMSCs) with our 3D capacitance sensor. PMID:26386332
A Growth Model for Multilevel Ordinal Data
ERIC Educational Resources Information Center
Segawa, Eisuke
2005-01-01
Multi-indicator growth models were formulated as special three-level hierarchical generalized linear models to analyze growth of a trait latent variable measured by ordinal items. Items are nested within a time-point, and time-points are nested within subject. These models are special because they include factor analytic structure. This model can…
Use of ordinal information by fish
Petrazzini, Maria Elena Miletto; Lucon-Xiccato, Tyrone; Agrillo, Christian; Bisazza, Angelo
2015-01-01
Mammals and birds can process ordinal numerical information which can be used, for instance, for recognising an object on the basis of its position in a sequence of similar objects. Recent studies have shown that teleost fish possess numerical abilities comparable to those of other vertebrates, but it is unknown if they can also learn ordinal numerical relations. Guppies (Poecilia reticulata) learned to recognise the 3rd feeder in a row of 8 identical ones even when inter-feeder distance and feeder positions were varied among trials to prevent the use of any spatial information. To assess whether guppies spontaneously use ordinal or spatial information when both are simultaneously available, fish were then trained with constant feeder positions and inter-feeder distance. In probe trials where these two sources of information were contrasted, the subjects selected the correct ordinal position significantly more often than the original spatial position, indicating that the former was preferentially encoded during training. Finally, a comparison between subjects trained on the 3rd and the 5th position revealed that guppies can also learn the latter discrimination, but the larger error rate observed in this case suggests that 5 is close to the upper limit of discrimination in guppies. PMID:26499450
How To Write a Municipal Tree Ordinance.
ERIC Educational Resources Information Center
Fazio, James R., Ed.
1990-01-01
At the heart of the Tree City USA program are four basic requirements: The community must have the following: (1) a tree board or department; (2) an annual community forestry program with financial provisions for trees and tree care; (3) an annual Arbor Day proclamation and observance; and (4) a tree ordinance. Sections of a model tree ordinance…
Spatial watermarking of 3D triangle meshes
NASA Astrophysics Data System (ADS)
Cayre, Francois; Macq, Benoit M. M.
2001-12-01
Although it is obvious that watermarking has become of great interest in protecting audio, videos, and still pictures, few work has been done considering 3D meshes. We propose a new method for watermarking 3D triangle meshes. This method embeds the watermark as triangles deformations. The list of watermarked triangles is obtained through a similar way to the one used in the TSPS (Triangle Strip Peeling Sequence) method. Unlike TSPS, our method is automatic and more secure. We also show that it is reversible.
Acquisition and applications of 3D images
NASA Astrophysics Data System (ADS)
Sterian, Paul; Mocanu, Elena
2007-08-01
The moiré fringes method and their analysis up to medical and entertainment applications are discussed in this paper. We describe the procedure of capturing 3D images with an Inspeck Camera that is a real-time 3D shape acquisition system based on structured light techniques. The method is a high-resolution one. After processing the images, using computer, we can use the data for creating laser fashionable objects by engraving them with a Q-switched Nd:YAG. In medical field we mention the plastic surgery and the replacement of X-Ray especially in pediatric use.
Superplastic forming using NIKE3D
Puso, M.
1996-12-04
The superplastic forming process requires careful control of strain rates in order to avoid strain localizations. A load scheduler was developed and implemented into the nonlinear finite element code NIKE3D to provide strain rate control during forming simulation and process schedule output. Often the sheets being formed in SPF are very thin such that less expensive membrane elements can be used as opposed to shell elements. A large strain membrane element was implemented into NIKE3D to assist in SPF process modeling.
The Galicia 3D experiment: an Introduction.
NASA Astrophysics Data System (ADS)
Reston, Timothy; Martinez Loriente, Sara; Holroyd, Luke; Merry, Tobias; Sawyer, Dale; Morgan, Julia; Jordan, Brian; Tesi Sanjurjo, Mari; Alexanian, Ara; Shillington, Donna; Gibson, James; Minshull, Tim; Karplus, Marianne; Bayracki, Gaye; Davy, Richard; Klaeschen, Dirk; Papenberg, Cord; Ranero, Cesar; Perez-Gussinye, Marta; Martinez, Miguel
2014-05-01
In June and July 2013, scientists from 8 institutions took part in the Galicia 3D seismic experiment, the first ever crustal -scale academic 3D MCS survey over a rifted margin. The aim was to determine the 3D structure of a critical portion of the west Galicia rifted margin. At this margin, well-defined tilted fault blocks, bound by west-dipping faults and capped by synrift sediments are underlain by a bright reflection, undulating on time sections, termed the S reflector and thought to represent a major detachment fault of some kind. Moving west, the crust thins to zero thickness and mantle is unroofed, as evidence by the "Peridotite Ridge" first reported at this margin, but since observed at many other magma-poor margins. By imaging such a margin in detail, the experiment aimed to resolve the processes controlling crustal thinning and mantle unroofing at a type example magma poor margin. The experiment set out to collect several key datasets: a 3D seismic reflection volume measuring ~20x64km and extending down to ~14s TWT, a 3D ocean bottom seismometer dataset suitable for full wavefield inversion (the recording of the complete 3D seismic shots by 70 ocean bottom instruments), the "mirror imaging" of the crust using the same grid of OBS, a single 2D combined reflection/refraction profile extending to the west to determine the transition from unroofed mantle to true oceanic crust, and the seismic imaging of the water column, calibrated by regular deployment of XBTs to measure the temperature structure of the water column. We collected 1280 km2 of seismic reflection data, consisting of 136533 shots recorded on 1920 channels, producing 260 million seismic traces, each ~ 14s long. This adds up to ~ 8 terabytes of data, representing, we believe, the largest ever academic 3D MCS survey in terms of both the area covered and the volume of data. The OBS deployment was the largest ever within an academic 3D survey.
3D Modeling Engine Representation Summary Report
Steven Prescott; Ramprasad Sampath; Curtis Smith; Timothy Yang
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 summary report addressed the methods, techniques, and resources used to develop a 3D modeling engine to represent risk analysis simulation for advanced small modular reactor structures and components. The simulations done for this evaluation were focused on external events, specifically tsunami floods, for a hypothetical nuclear power facility on a coastline.
Immersive 3D geovisualisation in higher education
NASA Astrophysics Data System (ADS)
Philips, Andrea; Walz, Ariane; Bergner, Andreas; Graeff, Thomas; Heistermann, Maik; Kienzler, Sarah; Korup, Oliver; Lipp, Torsten; Schwanghart, Wolfgang; Zeilinger, Gerold
2014-05-01
Through geovisualisation we explore spatial data, we analyse it towards a specific questions, we synthesise results, and we present and communicate them to a specific audience (MacEachren & Kraak 1997). After centuries of paper maps, the means to represent and visualise our physical environment and its abstract qualities have changed dramatically since the 1990s - and accordingly the methods how to use geovisualisation in teaching. Whereas some people might still consider the traditional classroom as ideal setting for teaching and learning geographic relationships and its mapping, we used a 3D CAVE (computer-animated virtual environment) as environment for a problem-oriented learning project called "GEOSimulator". Focussing on this project, we empirically investigated, if such a technological advance like the CAVE make 3D visualisation, including 3D geovisualisation, not only an important tool for businesses (Abulrub et al. 2012) and for the public (Wissen et al. 2008), but also for educational purposes, for which it had hardly been used yet. The 3D CAVE is a three-sided visualisation platform, that allows for immersive and stereoscopic visualisation of observed and simulated spatial data. We examined the benefits of immersive 3D visualisation for geographic research and education and synthesized three fundamental technology-based visual aspects: First, the conception and comprehension of space and location does not need to be generated, but is instantaneously and intuitively present through stereoscopy. Second, optical immersion into virtual reality strengthens this spatial perception which is in particular important for complex 3D geometries. And third, a significant benefit is interactivity, which is enhanced through immersion and allows for multi-discursive and dynamic data exploration and knowledge transfer. Based on our problem-oriented learning project, which concentrates on a case study on flood risk management at the Wilde Weisseritz in Germany, a river
3D printed diffractive terahertz lenses.
Furlan, Walter D; Ferrando, Vicente; Monsoriu, Juan A; Zagrajek, Przemysław; Czerwińska, Elżbieta; Szustakowski, Mieczysław
2016-04-15
A 3D printer was used to realize custom-made diffractive THz lenses. After testing several materials, phase binary lenses with periodic and aperiodic radial profiles were designed and constructed in polyamide material to work at 0.625 THz. The nonconventional focusing properties of such lenses were assessed by computing and measuring their axial point spread function (PSF). Our results demonstrate that inexpensive 3D printed THz diffractive lenses can be reliably used in focusing and imaging THz systems. Diffractive THz lenses with unprecedented features, such as extended depth of focus or bifocalization, have been demonstrated. PMID:27082335
Recent developments in DFD (depth-fused 3D) display and arc 3D display
NASA Astrophysics Data System (ADS)
Suyama, Shiro; Yamamoto, Hirotsugu
2015-05-01
We will report our recent developments in DFD (Depth-fused 3D) display and arc 3D display, both of which have smooth movement parallax. Firstly, fatigueless DFD display, composed of only two layered displays with a gap, has continuous perceived depth by changing luminance ratio between two images. Two new methods, called "Edge-based DFD display" and "Deep DFD display", have been proposed in order to solve two severe problems of viewing angle and perceived depth limitations. Edge-based DFD display, layered by original 2D image and its edge part with a gap, can expand the DFD viewing angle limitation both in 2D and 3D perception. Deep DFD display can enlarge the DFD image depth by modulating spatial frequencies of front and rear images. Secondly, Arc 3D display can provide floating 3D images behind or in front of the display by illuminating many arc-shaped directional scattering sources, for example, arcshaped scratches on a flat board. Curved Arc 3D display, composed of many directional scattering sources on a curved surface, can provide a peculiar 3D image, for example, a floating image in the cylindrical bottle. The new active device has been proposed for switching arc 3D images by using the tips of dual-frequency liquid-crystal prisms as directional scattering sources. Directional scattering can be switched on/off by changing liquid-crystal refractive index, resulting in switching of arc 3D image.
Innovations in 3D printing: a 3D overview from optics to organs.
Schubert, Carl; van Langeveld, Mark C; Donoso, Larry A
2014-02-01
3D printing is a method of manufacturing in which materials, such as plastic or metal, are deposited onto one another in layers to produce a three dimensional object, such as a pair of eye glasses or other 3D objects. This process contrasts with traditional ink-based printers which produce a two dimensional object (ink on paper). To date, 3D printing has primarily been used in engineering to create engineering prototypes. However, recent advances in printing materials have now enabled 3D printers to make objects that are comparable with traditionally manufactured items. In contrast with conventional printers, 3D printing has the potential to enable mass customisation of goods on a large scale and has relevance in medicine including ophthalmology. 3D printing has already been proved viable in several medical applications including the manufacture of eyeglasses, custom prosthetic devices and dental implants. In this review, we discuss the potential for 3D printing to revolutionise manufacturing in the same way as the printing press revolutionised conventional printing. The applications and limitations of 3D printing are discussed; the production process is demonstrated by producing a set of eyeglass frames from 3D blueprints. PMID:24288392
Innovations in 3D printing: a 3D overview from optics to organs.
Schubert, Carl; van Langeveld, Mark C; Donoso, Larry A
2014-02-01
3D printing is a method of manufacturing in which materials, such as plastic or metal, are deposited onto one another in layers to produce a three dimensional object, such as a pair of eye glasses or other 3D objects. This process contrasts with traditional ink-based printers which produce a two dimensional object (ink on paper). To date, 3D printing has primarily been used in engineering to create engineering prototypes. However, recent advances in printing materials have now enabled 3D printers to make objects that are comparable with traditionally manufactured items. In contrast with conventional printers, 3D printing has the potential to enable mass customisation of goods on a large scale and has relevance in medicine including ophthalmology. 3D printing has already been proved viable in several medical applications including the manufacture of eyeglasses, custom prosthetic devices and dental implants. In this review, we discuss the potential for 3D printing to revolutionise manufacturing in the same way as the printing press revolutionised conventional printing. The applications and limitations of 3D printing are discussed; the production process is demonstrated by producing a set of eyeglass frames from 3D blueprints.
NASA Astrophysics Data System (ADS)
Tjulin, A.; Mann, I.; McCrea, I.; Aikio, A. T.
2013-05-01
EISCAT_3D will be a world-leading international research infrastructure using the incoherent scatter technique to study the atmosphere in the Fenno-Scandinavian Arctic and to investigate how the Earth's atmosphere is coupled to space. The EISCAT_3D phased-array multistatic radar system will be operated by EISCAT Scientific Association and thus be an integral part of an organisation that has successfully been running incoherent scatter radars for more than thirty years. The baseline design of the radar system contains a core site with transmitting and receiving capabilities located close to the intersection of the Swedish, Norwegian and Finnish borders and five receiving sites located within 50 to 250 km from the core. The EISCAT_3D project is currently in its Preparatory Phase and can smoothly transit into implementation in 2014, provided sufficient funding. Construction can start 2016 and first operations in 2018. The EISCAT_3D Science Case is prepared as part of the Preparatory Phase. It is regularly updated with annual new releases, and it aims at being a common document for the whole future EISCAT_3D user community. The areas covered by the Science Case are atmospheric physics and global change; space and plasma physics; solar system research; space weather and service applications; and radar techniques, new methods for coding and analysis. Two of the aims for EISCAT_3D are to understand the ways natural variability in the upper atmosphere, imposed by the Sun-Earth system, can influence the middle and lower atmosphere, and to improve the predictivity of atmospheric models by providing higher resolution observations to replace the current parametrised input. Observations by EISCAT_3D will also be used to monitor the direct effects from the Sun on the ionosphere-atmosphere system and those caused by solar wind magnetosphere-ionosphere interaction. In addition, EISCAT_3D will be used for remote sensing the large-scale behaviour of the magnetosphere from its
Variational Symplectic Orbit Code in 3-D Tokamak Geometry
NASA Astrophysics Data System (ADS)
Ellison, Charles; Qin, Hong; Tang, William M.
2011-10-01
Since advanced tokamak experiments - including ITER - are long-pulse systems, it is important to develop accurate numerical methods to track plasma dynamics over an extended temporal period. When attempting to model the motion of individual particles, standard integrators (e.g. 4th order Runge-Kutta) discretize the differential equations of motion - but do not possess desired properties such as energy conservation. The variational symplectic integrator adopts instead a different approach via minimizing the action of the guiding center motion to determine iteration rules. Consequently, the Lagrangian symplectic structure is conserved, and the numerical energy error is bounded by a small number for all time-steps. In previous work, the theoretical basis for this method was introduced, but the implementation was for 2-D geometry. To address realistic experimental scenarios, the variational symplectic integrator has been implemented for 3-D tokamak geometry for the first time. Sample results will be presented and compared with those from standard Runge-Kutta-based 3-D tokamak orbit codes. This work was supported by the DOE contract # DE-AC02-09CH11466 and the DOE FES Fellowship.
Degeneracy-aware interpolation of 3D diffusion tensor fields
NASA Astrophysics Data System (ADS)
Bi, Chongke; Takahashi, Shigeo; Fujishiro, Issei
2012-01-01
Visual analysis of 3D diffusion tensor fields has become an important topic especially in medical imaging for understanding microscopic structures and physical properties of biological tissues. However, it is still difficult to continuously track the underlying features from discrete tensor samples, due to the absence of appropriate interpolation schemes in the sense that we are able to handle possible degeneracy while fully respecting the smooth transition of tensor anisotropic features. This is because the degeneracy may cause rotational inconsistency of tensor anisotropy. This paper presents such an approach to interpolating 3D diffusion tensor fields. The primary idea behind our approach is to resolve the possible degeneracy through optimizing the rotational transformation between a pair of neighboring tensors by analyzing their associated eigenstructure, while the degeneracy can be identified by applying a minimum spanning tree-based clustering algorithm to the original tensor samples. Comparisons with existing interpolation schemes will be provided to demonstrate the advantages of our scheme, together with several results of tracking white matter fiber bundles in a human brain.
White, Diana; Coombe, Dennis; Rezania, Vahid; Tuszynski, Jack
2016-01-01
In this paper, we develop a spatio-temporal modeling approach to describe blood and drug flow, as well as drug uptake and elimination, on an approximation of the liver. Extending on previously developed computational approaches, we generate an approximation of a liver, which consists of a portal and hepatic vein vasculature structure, embedded in the surrounding liver tissue. The vasculature is generated via constrained constructive optimization, and then converted to a spatial grid of a selected grid size. Estimates for surrounding upscaled lobule tissue properties are then presented appropriate to the same grid size. Simulation of fluid flow and drug metabolism (hepatic clearance) are completed using discretized forms of the relevant convective-diffusive-reactive partial differential equations for these processes. This results in a single stage, uniformly consistent method to simulate equations for blood and drug flow, as well as drug metabolism, on a 3D structure representative of a liver. PMID:27649537
Rezania, Vahid; Tuszynski, Jack
2016-01-01
In this paper, we develop a spatio-temporal modeling approach to describe blood and drug flow, as well as drug uptake and elimination, on an approximation of the liver. Extending on previously developed computational approaches, we generate an approximation of a liver, which consists of a portal and hepatic vein vasculature structure, embedded in the surrounding liver tissue. The vasculature is generated via constrained constructive optimization, and then converted to a spatial grid of a selected grid size. Estimates for surrounding upscaled lobule tissue properties are then presented appropriate to the same grid size. Simulation of fluid flow and drug metabolism (hepatic clearance) are completed using discretized forms of the relevant convective-diffusive-reactive partial differential equations for these processes. This results in a single stage, uniformly consistent method to simulate equations for blood and drug flow, as well as drug metabolism, on a 3D structure representative of a liver. PMID:27649537
Scoops3D: software to analyze 3D slope stability throughout a digital landscape
Reid, Mark E.; Christian, Sarah B.; Brien, Dianne L.; Henderson, Scott T.
2015-01-01
The computer program, Scoops3D, evaluates slope stability throughout a digital landscape represented by a digital elevation model (DEM). The program uses a three-dimensional (3D) method of columns approach to assess the stability of many (typically millions) potential landslides within a user-defined size range. For each potential landslide (or failure), Scoops3D assesses the stability of a rotational, spherical slip surface encompassing many DEM cells using a 3D version of either Bishop’s simplified method or the Ordinary (Fellenius) method of limit-equilibrium analysis. Scoops3D has several options for the user to systematically and efficiently search throughout an entire DEM, thereby incorporating the effects of complex surface topography. In a thorough search, each DEM cell is included in multiple potential failures, and Scoops3D records the lowest stability (factor of safety) for each DEM cell, as well as the size (volume or area) associated with each of these potential landslides. It also determines the least-stable potential failure for the entire DEM. The user has a variety of options for building a 3D domain, including layers or full 3D distributions of strength and pore-water pressures, simplistic earthquake loading, and unsaturated suction conditions. Results from Scoops3D can be readily incorporated into a geographic information system (GIS) or other visualization software. This manual includes information on the theoretical basis for the slope-stability analysis, requirements for constructing and searching a 3D domain, a detailed operational guide (including step-by-step instructions for using the graphical user interface [GUI] software, Scoops3D-i) and input/output file specifications, practical considerations for conducting an analysis, results of verification tests, and multiple examples illustrating the capabilities of Scoops3D. Easy-to-use software installation packages are available for the Windows or Macintosh operating systems; these packages
Effect of viewing distance on 3D fatigue caused by viewing mobile 3D content
NASA Astrophysics Data System (ADS)
Mun, Sungchul; Lee, Dong-Su; Park, Min-Chul; Yano, Sumio
2013-05-01
With an advent of autostereoscopic display technique and increased needs for smart phones, there has been a significant growth in mobile TV markets. The rapid growth in technical, economical, and social aspects has encouraged 3D TV manufacturers to apply 3D rendering technology to mobile devices so that people have more opportunities to come into contact with many 3D content anytime and anywhere. Even if the mobile 3D technology leads to the current market growth, there is an important thing to consider for consistent development and growth in the display market. To put it briefly, human factors linked to mobile 3D viewing should be taken into consideration before developing mobile 3D technology. Many studies have investigated whether mobile 3D viewing causes undesirable biomedical effects such as motion sickness and visual fatigue, but few have examined main factors adversely affecting human health. Viewing distance is considered one of the main factors to establish optimized viewing environments from a viewer's point of view. Thus, in an effort to determine human-friendly viewing environments, this study aims to investigate the effect of viewing distance on human visual system when exposing to mobile 3D environments. Recording and analyzing brainwaves before and after watching mobile 3D content, we explore how viewing distance affects viewing experience from physiological and psychological perspectives. Results obtained in this study are expected to provide viewing guidelines for viewers, help ensure viewers against undesirable 3D effects, and lead to make gradual progress towards a human-friendly mobile 3D viewing.
NASA Astrophysics Data System (ADS)
Shepherd, Orr; LePage, Andrew J.; Wijntjes, Geert J.; Zehnpfennig, Theodore F.; Sackos, John T.; Nellums, Robert O.
1999-01-01
Visidyne, Inc., teaming with Sandia National Laboratories, has developed the preliminary design for an innovative scannerless 3-D laser radar capable of acquiring, tracking, and determining the coordinates of small caliber projectiles in flight with sufficient precision, so their origin can be established by back projecting their tracks to their source. The design takes advantage of the relatively large effective cross-section of a bullet at optical wavelengths. Kay to its implementation is the use of efficient, high- power laser diode arrays for illuminators and an imaging laser receiver using a unique CCD imager design, that acquires the information to establish x, y (angle-angle) and range coordinates for each bullet at very high frame rates. The detection process achieves a high degree of discrimination by using the optical signature of the bullet, solar background mitigation, and track detection. Field measurements and computer simulations have been used to provide the basis for a preliminary design of a robust bullet tracker, the Counter Sniper 3-D Laser Radar. Experimental data showing 3-D test imagery acquired by a lidar with architecture similar to that of the proposed Counter Sniper 3-D Lidar are presented. A proposed Phase II development would yield an innovative, compact, and highly efficient bullet-tracking laser radar. Such a device would meet the needs of not only the military, but also federal, state, and local law enforcement organizations.
ERIC Educational Resources Information Center
Parikesit, Gea O. F.
2014-01-01
Shadows can be found easily everywhere around us, so that we rarely find it interesting to reflect on how they work. In order to raise curiosity among students on the optics of shadows, we can display the shadows in 3D, particularly using a stereoscopic set-up. In this paper we describe the optics of stereoscopic shadows using simple schematic…
Spatial Visualization by Realistic 3D Views
ERIC Educational Resources Information Center
Yue, Jianping
2008-01-01
In this study, the popular Purdue Spatial Visualization Test-Visualization by Rotations (PSVT-R) in isometric drawings was recreated with CAD software that allows 3D solid modeling and rendering to provide more realistic pictorial views. Both the original and the modified PSVT-R tests were given to students and their scores on the two tests were…
Virtual Representations in 3D Learning Environments
ERIC Educational Resources Information Center
Shonfeld, Miri; Kritz, Miki
2013-01-01
This research explores the extent to which virtual worlds can serve as online collaborative learning environments for students by increasing social presence and engagement. 3D environments enable learning, which simulates face-to-face encounters while retaining the advantages of online learning. Students in Education departments created avatars…
3D Cell Culture in Alginate Hydrogels
Andersen, Therese; Auk-Emblem, Pia; Dornish, Michael
2015-01-01
This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent), and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue. PMID:27600217
GPM 3D Flyby of Hurricane Lester
This 3-D flyby of Lester was created using GPM's Radar data. NASA/JAXA's GPM core observatory satellite flew over Hurricane Lester on August 29, 2016 at 7:21 p.m. EDT. Rain was measured by GPM's ra...
Invertible authentication for 3D meshes
NASA Astrophysics Data System (ADS)
Dittmann, Jana; Benedens, Oliver
2003-06-01
Digital watermarking has become an accepted technology for enabling multimedia protection schemes. Based on the introduced media independent protocol schemes for invertible data authentication in references 2, 4 and 5 we discuss the design of a new 3D invertible labeling technique to ensure and require high data integrity. We combine digital signature schemes and digital watermarking to provide a public verifiable integrity. Furthermore the protocol steps in the other papers to ensure that the original data can only be reproduced with a secret key is adopted for 3D meshes. The goal is to show how the existing protocol can be used for 3D meshes to provide solutions for authentication watermarking. In our design concept and evaluation we see that due to the nature of 3D meshes the invertible function are different from the image and audio concepts to achieve invertibility to guaranty reversibility of the original. Therefore we introduce a concept for distortion free invertibility and a concept for adjustable minimum distortion invertibility.
Metrological characterization of 3D imaging devices
NASA Astrophysics Data System (ADS)
Guidi, G.
2013-04-01
Manufacturers often express the performance of a 3D imaging device in various non-uniform ways for the lack of internationally recognized standard requirements for metrological parameters able to identify the capability of capturing a real scene. For this reason several national and international organizations in the last ten years have been developing protocols for verifying such performance. Ranging from VDI/VDE 2634, published by the Association of German Engineers and oriented to the world of mechanical 3D measurements (triangulation-based devices), to the ASTM technical committee E57, working also on laser systems based on direct range detection (TOF, Phase Shift, FM-CW, flash LADAR), this paper shows the state of the art about the characterization of active range devices, with special emphasis on measurement uncertainty, accuracy and resolution. Most of these protocols are based on special objects whose shape and size are certified with a known level of accuracy. By capturing the 3D shape of such objects with a range device, a comparison between the measured points and the theoretical shape they should represent is possible. The actual deviations can be directly analyzed or some derived parameters can be obtained (e.g. angles between planes, distances between barycenters of spheres rigidly connected, frequency domain parameters, etc.). This paper shows theoretical aspects and experimental results of some novel characterization methods applied to different categories of active 3D imaging devices based on both principles of triangulation and direct range detection.
[3D virtual endoscopy of heart].
Du, Aan; Yang, Xin; Xue, Haihong; Yao, Liping; Sun, Kun
2012-10-01
In this paper, we present a virtual endoscopy (VE) for diagnosis of heart diseases, which is proved efficient and affordable, easy to popularize for viewing the interior of the heart. The dual source CT (DSCT) data were used as primary data in our system. The 3D structure of virtual heart was reconstructed with 3D texture mapping technology based on graphics processing unit (GPU), and could be displayed dynamically in real time. When we displayed it in real time, we could not only observe the inside of the chambers of heart but also examine from the new angle of view by the 3D data which were already clipped according to doctor's desire. In the pattern of observation, we used both mutual interactive mode and auto mode. In the auto mode, we used Dijkstra Algorithm which treated the 3D Euler distance as weighting factor to find out the view path quickly, and, used view path to calculate the four chamber plane. PMID:23198444
3D Virtual Reality for Teaching Astronomy
NASA Astrophysics Data System (ADS)
Speck, Angela; Ruzhitskaya, L.; Laffey, J.; Ding, N.
2012-01-01
We are developing 3D virtual learning environments (VLEs) as learning materials for an undergraduate astronomy course, in which will utilize advances both in technologies available and in our understanding of the social nature of learning. These learning materials will be used to test whether such VLEs can indeed augment science learning so that it is more engaging, active, visual and effective. Our project focuses on the challenges and requirements of introductory college astronomy classes. Here we present our virtual world of the Jupiter system and how we plan to implement it to allow students to learn course material - physical laws and concepts in astronomy - while engaging them into exploration of the Jupiter's system, encouraging their imagination, curiosity, and motivation. The VLE can allow students to work individually or collaboratively. The 3D world also provides an opportunity for research in astronomy education to investigate impact of social interaction, gaming features, and use of manipulatives offered by a learning tool on students’ motivation and learning outcomes. Use of this VLE is also a valuable source for exploration of how the learners’ spatial awareness can be enhanced by working in 3D environment. We will present the Jupiter-system environment along with a preliminary study of the efficacy and usability of our Jupiter 3D VLE.
3D Cell Culture in Alginate Hydrogels
Andersen, Therese; Auk-Emblem, Pia; Dornish, Michael
2015-01-01
This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent), and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue.
Collaborative annotation of 3D crystallographic models.
Hunter, J; Henderson, M; Khan, I
2007-01-01
This paper describes the AnnoCryst system-a tool that was designed to enable authenticated collaborators to share online discussions about 3D crystallographic structures through the asynchronous attachment, storage, and retrieval of annotations. Annotations are personal comments, interpretations, questions, assessments, or references that can be attached to files, data, digital objects, or Web pages. The AnnoCryst system enables annotations to be attached to 3D crystallographic models retrieved from either private local repositories (e.g., Fedora) or public online databases (e.g., Protein Data Bank or Inorganic Crystal Structure Database) via a Web browser. The system uses the Jmol plugin for viewing and manipulating the 3D crystal structures but extends Jmol by providing an additional interface through which annotations can be created, attached, stored, searched, browsed, and retrieved. The annotations are stored on a standardized Web annotation server (Annotea), which has been extended to support 3D macromolecular structures. Finally, the system is embedded within a security framework that is capable of authenticating users and restricting access only to trusted colleagues.
A Rotation Invariant in 3-D Reaching
ERIC Educational Resources Information Center
Mitra, Suvobrata; Turvey, M. T.
2004-01-01
In 3 experiments, the authors investigated changes in hand orientation during a 3-D reaching task that imposed specific position and orientation requirements on the hand's initial and final postures. Instantaneous hand orientation was described using 3-element rotation vectors representing current orientation as a rotation from a fixed reference…
Spacecraft 3D Augmented Reality Mobile App
NASA Technical Reports Server (NTRS)
Hussey, Kevin J.; Doronila, Paul R.; Kumanchik, Brian E.; Chan, Evan G.; Ellison, Douglas J.; Boeck, Andrea; Moore, Justin M.
2013-01-01
The Spacecraft 3D application allows users to learn about and interact with iconic NASA missions in a new and immersive way using common mobile devices. Using Augmented Reality (AR) techniques to project 3D renditions of the mission spacecraft into real-world surroundings, users can interact with and learn about Curiosity, GRAIL, Cassini, and Voyager. Additional updates on future missions, animations, and information will be ongoing. Using a printed AR Target and camera on a mobile device, users can get up close with these robotic explorers, see how some move, and learn about these engineering feats, which are used to expand knowledge and understanding about space. The software receives input from the mobile device's camera to recognize the presence of an AR marker in the camera's field of view. It then displays a 3D rendition of the selected spacecraft in the user's physical surroundings, on the mobile device's screen, while it tracks the device's movement in relation to the physical position of the spacecraft's 3D image on the AR marker.
NASA Technical Reports Server (NTRS)
2002-01-01
Dimension Technologies Inc., developed a line of 2-D/3-D Liquid Crystal Display (LCD) screens, including a 15-inch model priced at consumer levels. DTI's family of flat panel LCD displays, called the Virtual Window(TM), provide real-time 3-D images without the use of glasses, head trackers, helmets, or other viewing aids. Most of the company initial 3-D display research was funded through NASA's Small Business Innovation Research (SBIR) program. The images on DTI's displays appear to leap off the screen and hang in space. The display accepts input from computers or stereo video sources, and can be switched from 3-D to full-resolution 2-D viewing with the push of a button. The Virtual Window displays have applications in data visualization, medicine, architecture, business, real estate, entertainment, and other research, design, military, and consumer applications. Displays are currently used for computer games, protein analysis, and surgical imaging. The technology greatly benefits the medical field, as surgical simulators are helping to increase the skills of surgical residents. Virtual Window(TM) is a trademark of Dimension Technologies Inc.
NASA Sees Typhoon Rammasun in 3-D
NASA's TRMM satellite flew over on July 14, 2014 at 1819 UTC and data was used to make this 3-D flyby showing thunderstorms to heights of almost 17km (10.5 miles). Rain was measured falling at a ra...
ERIC Educational Resources Information Center
Bradley, Joan; Farland-Smith, Donna
2010-01-01
Allowing a student to "see" through touch what other students see through a microscope can be a challenging task. Therefore, author Joan Bradley created three-dimensional (3-D) models with one student's visual impairment in mind. They are meant to benefit all students and can be used to teach common high school biology topics, including the…
Evolution of Archaea in 3D modeling
NASA Astrophysics Data System (ADS)
Pikuta, Elena V.; Tankosic, Dragana; Sheldon, Rob
2012-11-01
The analysis of all groups of Archaea performed in two-dimensions have demonstrated a specific distribution of Archaean species as a function of pH/temperature, temperature/salinity and pH/salinity. Work presented here is an extension of this analysis with a three dimensional (3D) modeling in logarithmic scale. As it was shown in 2D representation, the "Rules of the Diagonal" have been expressed even more clearly in 3D modeling. In this article, we used a 3D Mesh modeling to show the range of distribution of each separate group of Archaea as a function of pH, temperature, and salinity. Visible overlap and links between different groups indicate a direction of evolution in Archaea. The major direction in ancestral life (vector of evolution) has been indicated: from high temperature, acidic, and low-salinity system towards low temperature, alkaline and high salinity systems. Specifics of the geometrical coordinates and distribution of separate groups of Archaea in 3 D scale were analyzed with a mathematical description of the functions. Based on the obtained data, a new model for the origin and evolution of life on Earth is proposed. The geometry of this model is described by a hyperboloid of one sheet. Conclusions of this research are consistent with previous results derived from the two-dimensional diagrams. This approach is suggested as a new method for analyzing any biological group in accordance to its environmental parameters.
Introduction to 3D Graphics through Excel
ERIC Educational Resources Information Center
Benacka, Jan
2013-01-01
The article presents a method of explaining the principles of 3D graphics through making a revolvable and sizable orthographic parallel projection of cuboid in Excel. No programming is used. The method was tried in fourteen 90 minute lessons with 181 participants, which were Informatics teachers, undergraduates of Applied Informatics and gymnasium…
3D Cell Culture in Alginate Hydrogels.
Andersen, Therese; Auk-Emblem, Pia; Dornish, Michael
2015-03-24
This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent), and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell-matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue.
Confirmatory Factor Analysis of Ordinal Variables with Misspecified Models
ERIC Educational Resources Information Center
Yang-Wallentin, Fan; Joreskog, Karl G.; Luo, Hao
2010-01-01
Ordinal variables are common in many empirical investigations in the social and behavioral sciences. Researchers often apply the maximum likelihood method to fit structural equation models to ordinal data. This assumes that the observed measures have normal distributions, which is not the case when the variables are ordinal. A better approach is…
3D Printed Programmable Release Capsules.
Gupta, Maneesh K; Meng, Fanben; Johnson, Blake N; Kong, Yong Lin; Tian, Limei; Yeh, Yao-Wen; Masters, Nina; Singamaneni, Srikanth; McAlpine, Michael C
2015-08-12
The development of methods for achieving precise spatiotemporal control over chemical and biomolecular gradients could enable significant advances in areas such as synthetic tissue engineering, biotic-abiotic interfaces, and bionanotechnology. Living organisms guide tissue development through highly orchestrated gradients of biomolecules that direct cell growth, migration, and differentiation. While numerous methods have been developed to manipulate and implement biomolecular gradients, integrating gradients into multiplexed, three-dimensional (3D) matrices remains a critical challenge. Here we present a method to 3D print stimuli-responsive core/shell capsules for programmable release of multiplexed gradients within hydrogel matrices. These capsules are composed of an aqueous core, which can be formulated to maintain the activity of payload biomolecules, and a poly(lactic-co-glycolic) acid (PLGA, an FDA approved polymer) shell. Importantly, the shell can be loaded with plasmonic gold nanorods (AuNRs), which permits selective rupturing of the capsule when irradiated with a laser wavelength specifically determined by the lengths of the nanorods. This precise control over space, time, and selectivity allows for the ability to pattern 2D and 3D multiplexed arrays of enzyme-loaded capsules along with tunable laser-triggered rupture and release of active enzymes into a hydrogel ambient. The advantages of this 3D printing-based method include (1) highly monodisperse capsules, (2) efficient encapsulation of biomolecular payloads, (3) precise spatial patterning of capsule arrays, (4) "on the fly" programmable reconfiguration of gradients, and (5) versatility for incorporation in hierarchical architectures. Indeed, 3D printing of programmable release capsules may represent a powerful new tool to enable spatiotemporal control over biomolecular gradients. PMID:26042472
Parallel CARLOS-3D code development
Putnam, J.M.; Kotulski, J.D.
1996-02-01
CARLOS-3D is a three-dimensional scattering code which was developed under the sponsorship of the Electromagnetic Code Consortium, and is currently used by over 80 aerospace companies and government agencies. The code has been extensively validated and runs on both serial workstations and parallel super computers such as the Intel Paragon. CARLOS-3D is a three-dimensional surface integral equation scattering code based on a Galerkin method of moments formulation employing Rao- Wilton-Glisson roof-top basis for triangular faceted surfaces. Fully arbitrary 3D geometries composed of multiple conducting and homogeneous bulk dielectric materials can be modeled. This presentation describes some of the extensions to the CARLOS-3D code, and how the operator structure of the code facilitated these improvements. Body of revolution (BOR) and two-dimensional geometries were incorporated by simply including new input routines, and the appropriate Galerkin matrix operator routines. Some additional modifications were required in the combined field integral equation matrix generation routine due to the symmetric nature of the BOR and 2D operators. Quadrilateral patched surfaces with linear roof-top basis functions were also implemented in the same manner. Quadrilateral facets and triangular facets can be used in combination to more efficiently model geometries with both large smooth surfaces and surfaces with fine detail such as gaps and cracks. Since the parallel implementation in CARLOS-3D is at high level, these changes were independent of the computer platform being used. This approach minimizes code maintenance, while providing capabilities with little additional effort. Results are presented showing the performance and accuracy of the code for some large scattering problems. Comparisons between triangular faceted and quadrilateral faceted geometry representations will be shown for some complex scatterers.
3-D Force-balanced Magnetospheric Configurations
Sorin Zaharia; C.Z. Cheng; K. Maezawa
2003-02-10
The knowledge of plasma pressure is essential for many physics applications in the magnetosphere, such as computing magnetospheric currents and deriving magnetosphere-ionosphere coupling. A thorough knowledge of the 3-D pressure distribution has however eluded the community, as most in-situ pressure observations are either in the ionosphere or the equatorial region of the magnetosphere. With the assumption of pressure isotropy there have been attempts to obtain the pressure at different locations by either (a) mapping observed data (e.g., in the ionosphere) along the field lines of an empirical magnetospheric field model or (b) computing a pressure profile in the equatorial plane (in 2-D) or along the Sun-Earth axis (in 1-D) that is in force balance with the magnetic stresses of an empirical model. However, the pressure distributions obtained through these methods are not in force balance with the empirical magnetic field at all locations. In order to find a global 3-D plasma pressure distribution in force balance with the magnetospheric magnetic field, we have developed the MAG-3D code, that solves the 3-D force balance equation J x B = (upside-down delta) P computationally. Our calculation is performed in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials as B = (upside-down delta) psi x (upside-down delta) alpha. The pressure distribution, P = P(psi,alpha), is prescribed in the equatorial plane and is based on satellite measurements. In addition, computational boundary conditions for y surfaces are imposed using empirical field models. Our results provide 3-D distributions of magnetic field and plasma pressure as well as parallel and transverse currents for both quiet-time and disturbed magnetospheric conditions.