NASA Astrophysics Data System (ADS)
Li, Zong-nan; Xie, Jing; Zhang, Jian
2014-11-01
Chlorophyll content and distribution in leaf can reflect the plant health and nutrient status of the plant indirectly. It is meaningful to monitor the 3D distribution of chlorophyll in plant science. It can be done by the method in this paper: Firstly, the chlorophyll contents at different point in leaf are measured with the SPAD-502 chlorophyll meter, and the RGN images composed by the channel R, G and NIR are captured with the imaging system. Secondly, the 3D model is built from the RGN images and the RGN texture map containing all the information of R, G and NIR is generated. Thirdly, the regression model between chlorophyll content and color characteristics is established. Finally, the 3D distribution of chlorophyll in rice is captured by mapping the 2D distribution map of chlorophyll calculated by the regression model to the 3D model. This methodology achieves the combination of phenotype and physiology, it can calculated the 3D distribution of chlorophyll in rice well. The color characteristic g is good indicator of chlorophyll content which can be used to measure the 3D distribution of chlorophyll quickly. Moreover, the methodology can be used to high throughout analyze the rice.
Proton Depth Dose Distribution: 3-D Calculation of Dose Distributions from Solar Flare Irradiation
1990-11-01
distributions in the transverse plane intersecting isocenter are presented for each of the 3 solar flare event. in all 3 exposure geometries. In all 3...calculation con- figurations the maximum predicted",dose occurred on the surface of the head. The dose at the isocenter of the head relative ’to the...for all 3 cases ire: 1. All isodose distributions are displayed relative to a normalization dose of 100 centigray at the isocenter in the absence of
NASA Astrophysics Data System (ADS)
Lin, Zhili; Li, Xiaoyan; Zhao, Kuixia; Chen, Xudong; Chen, Mingyu; Pu, Jixiong
2016-06-01
For an inertial confinement fusion (ICF) system, the light intensity distribution in the hohlraum is key to the initial plasma excitation and later laser-plasma interaction process. Based on the concept of coordinate transformation of spatial points and vector, we present a robust method with a detailed procedure that makes the calculation of the three dimensional (3D) light intensity distribution in hohlraum easily. The method is intuitive but powerful enough to solve the complex cases of random number of laser beams with arbitrary polarization states and incidence angles. Its application is exemplified in the Shenguang III Facility (SG-III) that verifies its effectiveness and it is useful for guiding the design of hohlraum structure parameter.
A graphical user interface for calculation of 3D dose distribution using Monte Carlo simulations
NASA Astrophysics Data System (ADS)
Chow, J. C. L.; Leung, M. K. K.
2008-02-01
A software graphical user interface (GUI) for calculation of 3D dose distribution using Monte Carlo (MC) simulation is developed using MATLAB. This GUI (DOSCTP) provides a user-friendly platform for DICOM CT-based dose calculation using EGSnrcMP-based DOSXYZnrc code. It offers numerous features not found in DOSXYZnrc, such as the ability to use multiple beams from different phase-space files, and has built-in dose analysis and visualization tools. DOSCTP is written completely in MATLAB, with integrated access to DOSXYZnrc and CTCREATE. The program function may be divided into four subgroups, namely, beam placement, MC simulation with DOSXYZnrc, dose visualization, and export. Each is controlled by separate routines. The verification of DOSCTP was carried out by comparing plans with different beam arrangements (multi-beam/photon arc) on an inhomogeneous phantom as well as patient CT between the GUI and Pinnacle3. DOSCTP was developed and verified with the following features: (1) a built-in voxel editor to modify CT-based DOSXYZnrc phantoms for research purposes; (2) multi-beam placement is possible, which cannot be achieved using the current DOSXYZnrc code; (3) the treatment plan, including the dose distributions, contours and image set can be exported to a commercial treatment planning system such as Pinnacle3 or to CERR using RTOG format for plan evaluation and comparison; (4) a built-in RTOG-compatible dose reviewer for dose visualization and analysis such as finding the volume of hot/cold spots in the 3D dose distributions based on a user threshold. DOSCTP greatly simplifies the use of DOSXYZnrc and CTCREATE, and offers numerous features that not found in the original user-code. Moreover, since phase-space beams can be defined and generated by the user, it is a particularly useful tool to carry out plans using specifically designed irradiators/accelerators that cannot be found in the Linac library of commercial treatment planning systems.
3D dose distribution calculation in a voxelized human phantom by means of Monte Carlo method.
Abella, V; Miró, R; Juste, B; Verdú, G
2010-01-01
The aim of this work is to provide the reconstruction of a real human voxelized phantom by means of a MatLab program and the simulation of the irradiation of such phantom with the photon beam generated in a Theratron 780 (MDS Nordion) (60)Co radiotherapy unit, by using the Monte Carlo transport code MCNP (Monte Carlo N-Particle), version 5. The project results in 3D dose mapping calculations inside the voxelized antropomorphic head phantom. The program provides the voxelization by first processing the CT slices; the process follows a two-dimensional pixel and material identification algorithm on each slice and three-dimensional interpolation in order to describe the phantom geometry via small cubic cells, resulting in an MCNP input deck format output. Dose rates are calculated by using the MCNP5 tool FMESH, superimposed mesh tally, which gives the track length estimation of the particle flux in units of particles/cm(2). Furthermore, the particle flux is converted into dose by using the conversion coefficients extracted from the NIST Physical Reference Data. The voxelization using a three-dimensional interpolation technique in combination with the use of the FMESH tool of the MCNP Monte Carlo code offers an optimal simulation which results in 3D dose mapping calculations inside anthropomorphic phantoms. This tool is very useful in radiation treatment assessments, in which voxelized phantoms are widely utilized. Copyright 2009 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Przybycin, Anna M.; Scheck-Wenderoth, Magdalena; Schneider, Michael
2014-05-01
The North Alpine Foreland Basin is situated in the northern front of the European Alps and extends over parts of France, Switzerland, Germany and Austria. It formed as a wedge shaped depression since the Tertiary in consequence of the Euro - Adriatic continental collision and the Alpine orogeny. The basin is filled with clastic sediments, the Molasse, originating from erosional processes of the Alps and underlain by Mesozoic sedimentary successions and a Paleozoic crystalline crust. For our study we have focused on the German part of the basin. To investigate the deep structure, the isostatic state and the load distribution of this region we have constructed a 3D structural model of the basin and the Alpine area using available depth and thickness maps, regional scale 3D structural models as well as seismic and well data for the sedimentary part. The crust (from the top Paleozoic down to the Moho (Grad et al. 2008)) has been considered as two-parted with a lighter upper crust and a denser lower crust; the partition has been calculated following the approach of isostatic equilibrium of Pratt (1855). By implementing a seismic Lithosphere-Asthenosphere-Boundary (LAB) (Tesauro 2009) the crustal scale model has been extended to the lithospheric-scale. The layer geometry and the assigned bulk densities of this starting model have been constrained by means of 3D gravity modelling (BGI, 2012). Afterwards the 3D load distribution has been calculated using a 3D finite element method. Our results show that the North Alpine Foreland Basin is not isostatically balanced and that the configuration of the crystalline crust strongly controls the gravity field in this area. Furthermore, our results show that the basin area is influenced by varying lateral load differences down to a depth of more than 150 km what allows a first order statement of the required compensating horizontal stress needed to prevent gravitational collapse of the system. BGI (2012). The International
Sofronov, I.D.; Voronin, B.L.; Butnev, O.I.
1997-12-31
The aim of the work performed is to develop a 3D parallel program for numerical calculation of gas dynamics problem with heat conductivity on distributed memory computational systems (CS), satisfying the condition of numerical result independence from the number of processors involved. Two basically different approaches to the structure of massive parallel computations have been developed. The first approach uses the 3D data matrix decomposition reconstructed at temporal cycle and is a development of parallelization algorithms for multiprocessor CS with shareable memory. The second approach is based on using a 3D data matrix decomposition not reconstructed during a temporal cycle. The program was developed on 8-processor CS MP-3 made in VNIIEF and was adapted to a massive parallel CS Meiko-2 in LLNL by joint efforts of VNIIEF and LLNL staffs. A large number of numerical experiments has been carried out with different number of processors up to 256 and the efficiency of parallelization has been evaluated in dependence on processor number and their parameters.
NASA Astrophysics Data System (ADS)
Chahal, Sanmeet; Wilkins, Mathew M.; Masson, Denis P.; Fafard, Simon; Valdivia, Christopher E.; Hinzer, Karin
2017-04-01
Distributed circuit models (DCM) divide photovoltaic devices into discrete elementary units. Each unit is assigned an equivalent circuit based on geometry and location, with circuit parameters being fit to or extrapolated from experimental results. Interconnection of these elementary units with ohmic resistors representing lateral and vertical resistances within the layers of the device forms the complete circuit model. DCMs allow grid design optimization, simulation of chromatic aberration, luminescent coupling and analysis of power losses due to regionally specific resistances, which are not possible with simple lumped models. Previous DCMs have been limited to 1-3 junction devices, using a 2D surface model, or use of a one-diode circuit model for the cell junctions. Furthermore, a DCM can be used to simulate complex multi-junction devices with non-uniform illumination, whereas in comprehensive physics-based simulators like Synopsys TCAD Sentaurus this would require vastly greater computational resources. In this work, a parameterized 3D distributed circuit model was developed to calculate the performance of III-V solar cells and photonic power converters (PPC) with a variable number of epitaxially stacked pn junctions. We validated these calculations against published results using a similar 3D model for a 1-junction solar cell. Furthermore, experimental results from Azastra Opto's 20-junction PPC illuminated by an 845 nm diode laser are compared. These devices are designed with many pn junctions to achieve higher voltages and to operate under non-uniform illumination profiles from a laser or LED. The effect on device performance of varying both these parameters will be discussed.
NASA Astrophysics Data System (ADS)
Harvey, R. W.; Petrov, Yu. V.; Kinsey, J. E.; Liu, D.; Heidbrink, W. W.; Taylor, G.; Bonoli, P. T.
2014-10-01
Ion distribution function calculations with CQL3D have been substantially advanced through implementation of guiding-center-orbit-based Fokker-Planck Coefficients. The resulting finite-orbit-width (FOW) calculations are carried out with a fast CQL3D-Hybrid-FOW option, and in a slower but neoclassically complete (except no Er yet) CQL3D-FOW option. Good comparison between time-dependent Fast Ion Diagnostic FIDA, NPA, and neutron signals resulting from neutral beaminjection(NBI) and high harmonic fast wave (HHFW) power injected into the NSTX spherical tokamak have been simulated with the CQL3D-Hybrid-FOW, using only the FOW effects on QL diffusion, and particle losses, direct and CX. Comparisons are also made with recent CQL3D-FOW results, as well as between the original FIDA calculation code and a recent fortran version. Supported by USDOE Grants SC0006614, ER54744, and ER44649.
Haeger-Eugensson, Marie; Ferm, Martin; Elfman, Lena
2014-03-31
The interest in equestrian sports has increased substantially during the last decades, resulting in increased number of horse facilities around urban areas. In Sweden, new guidelines for safe distance have been decided based on the size of the horse facility (e.g., number of horses) and local conditions, such as topography and meteorology. There is therefore an increasing need to estimate dispersion of horse allergens to be used, for example, in the planning processes for new residential areas in the vicinity of horse facilities. The aim of this study was to develop a method for calculating short- and long-term emissions and dispersion of horse allergen and odor around horse facilities. First, a method was developed to estimate horse allergen and odor emissions at hourly resolution based on field measurements. Secondly, these emission factors were used to calculate concentrations of horse allergen and odor by using 3-D dispersion modeling. Results from these calculations showed that horse allergens spread up to about 200 m, after which concentration levels were very low (<2 U/m³). Approximately 10% of a study-group detected the smell of manure at 60m, while the majority--80%-90%--detected smell at 60 m or shorter distance from the manure heap. Modeling enabled horse allergen exposure concentrations to be determined with good time resolution.
NASA Astrophysics Data System (ADS)
Pacilio, Massimiliano; Amato, Ernesto; Lanconelli, Nico; Basile, Chiara; Torres, Leonel Alberto; Botta, Francesca; Ferrari, Mahila; Cornejo Diaz, Nestor; Coca Perez, Marco; Fernández, María; Lassmann, Michael; Vergara Gil, Alex; Cremonesi, Marta
2015-03-01
This study compares 3D dose distributions obtained with voxel S values (VSVs) for soft tissue, calculated by several methods at their current state-of-the-art, varying the degree of image blurring. The methods were: 1) convolution of Dose Point Kernel (DPK) for water, using a scaling factor method; 2) an analytical model (AM), fitting the deposited energy as a function of the source-target distance; 3) a rescaling method (RSM) based on a set of high-resolution VSVs for each isotope; 4) local energy deposition (LED). VSVs calculated by direct Monte Carlo simulations were assumed as reference. Dose distributions were calculated considering spheroidal clusters with various sizes (251, 1237 and 4139 voxels of 3 mm size), uniformly filled with 131I, 177Lu, 188Re or 90Y. The activity distributions were blurred with Gaussian filters of various widths (6, 8 and 12 mm). Moreover, 3D-dosimetry was performed for 10 treatments with 90Y derivatives. Cumulative Dose Volume Histograms (cDVHs) were compared, studying the differences in D95%, D50% or Dmax (ΔD95%, ΔD50% and ΔDmax) and dose profiles. For unblurred spheroidal clusters, ΔD95%, ΔD50% and ΔDmax were mostly within some percents, slightly higher for 177Lu with DPK (8%) and RSM (12%) and considerably higher for LED (ΔD95% up to 59%). Increasing the blurring, differences decreased and also LED yielded very similar results, but D95% and D50% underestimations between 30-60% and 15-50%, respectively (with respect to 3D-dosimetry with unblurred distributions), were evidenced. Also for clinical images (affected by blurring as well), cDVHs differences for most methods were within few percents, except for slightly higher differences with LED, and almost systematic for dose profiles with DPK (-1.2%), AM (-3.0%) and RSM (4.5%), whereas showed an oscillating trend with LED. The major concern for 3D-dosimetry on clinical SPECT images is more strongly represented by image blurring than by differences among the VSVs
Pacilio, Massimiliano; Amato, Ernesto; Lanconelli, Nico; Basile, Chiara; Torres, Leonel Alberto; Botta, Francesca; Ferrari, Mahila; Diaz, Nestor Cornejo; Perez, Marco Coca; Fernández, María; Lassmann, Michael; Gil, Alex Vergara; Cremonesi, Marta
2015-03-07
This study compares 3D dose distributions obtained with voxel S values (VSVs) for soft tissue, calculated by several methods at their current state-of-the-art, varying the degree of image blurring. The methods were: 1) convolution of Dose Point Kernel (DPK) for water, using a scaling factor method; 2) an analytical model (AM), fitting the deposited energy as a function of the source-target distance; 3) a rescaling method (RSM) based on a set of high-resolution VSVs for each isotope; 4) local energy deposition (LED). VSVs calculated by direct Monte Carlo simulations were assumed as reference. Dose distributions were calculated considering spheroidal clusters with various sizes (251, 1237 and 4139 voxels of 3 mm size), uniformly filled with (131)I, (177)Lu, (188)Re or (90)Y. The activity distributions were blurred with Gaussian filters of various widths (6, 8 and 12 mm). Moreover, 3D-dosimetry was performed for 10 treatments with (90)Y derivatives. Cumulative Dose Volume Histograms (cDVHs) were compared, studying the differences in D95%, D50% or Dmax (ΔD95%, ΔD50% and ΔDmax) and dose profiles.For unblurred spheroidal clusters, ΔD95%, ΔD50% and ΔDmax were mostly within some percents, slightly higher for (177)Lu with DPK (8%) and RSM (12%) and considerably higher for LED (ΔD95% up to 59%). Increasing the blurring, differences decreased and also LED yielded very similar results, but D95% and D50% underestimations between 30-60% and 15-50%, respectively (with respect to 3D-dosimetry with unblurred distributions), were evidenced. Also for clinical images (affected by blurring as well), cDVHs differences for most methods were within few percents, except for slightly higher differences with LED, and almost systematic for dose profiles with DPK (-1.2%), AM (-3.0%) and RSM (4.5%), whereas showed an oscillating trend with LED.The major concern for 3D-dosimetry on clinical SPECT images is more strongly represented by image blurring than by differences among the VSVs
NASA Astrophysics Data System (ADS)
Harvey, R. W. (Bob); Petrov, Yu. V.; Jaeger, E. F.; Berry, L. A.; Bonoli, P. T.; Bader, A.
2015-11-01
A time-dependent simulation of C-Mod pulsed ICRF power is made calculating minority hydrogen ion distribution functions with the CQL3D-Hybrid-FOW finite-orbit-width Fokker-Planck code. ICRF fields are calculated with the AORSA full wave code, and RF diffusion coefficients are obtained from these fields using the DC Lorentz gyro-orbit code. Prior results with a zero-banana-width simulation using the CQL3D/AORSA/DC time-cycles showed a pronounced enhancement of the H distribution in the perpendicular velocity direction compared to results obtained from Stix's quasilinear theory, in general agreement with experiment. The present study compares the new FOW results, including relevant gyro-radius effects, to determine the importance of these effects on the the NPA synthetic diagnostic time-dependence. The new NPA results give increased agreement with experiment, particularly in the ramp-down time after the ICRF pulse. Funded, through subcontract with Massachusetts Institute of Technology, by USDOE sponsored SciDAC Center for Simulation of Wave-Plasma Interactions.
RHOCUBE: 3D density distributions modeling code
NASA Astrophysics Data System (ADS)
Nikutta, Robert; Agliozzo, Claudia
2016-11-01
RHOCUBE models 3D density distributions on a discrete Cartesian grid and their integrated 2D maps. It can be used for a range of applications, including modeling the electron number density in LBV shells and computing the emission measure. The RHOCUBE Python package provides several 3D density distributions, including a powerlaw shell, truncated Gaussian shell, constant-density torus, dual cones, and spiralling helical tubes, and can accept additional distributions. RHOCUBE provides convenient methods for shifts and rotations in 3D, and if necessary, an arbitrary number of density distributions can be combined into the same model cube and the integration ∫ dz performed through the joint density field.
NASA Astrophysics Data System (ADS)
Yang, Wanmin; Yang, Pengtao; Wang, Yanan; Li, Qiang
2017-09-01
The lower critical temperature Tc and critical current density Jc are serious weaknesses of SmBCO bulk superconductors fabricated in air for practical applications, because of the Sm3+/Ba2+ solid solution in Sm1+xBa2-xCu3Oy crystals. In this paper, high quality single domain SmBCO bulk samples S1 (ϕ20 mm) and S2 (ϕ32 mm) have been fabricated in air by a new Sm+011 TSIG method. The trapped field of the samples is 0.8 T and 1.15 T at liquid nitrogen temperature for the samples S1 and S2 respectively, which is the strongest trapped field of the SmBCO samples fabricated in air today. The theoretical formula for 3D trapped field distribution have been derived for a cylindrical model with uniformly distributed critical current density Jc based on the Biot Savart law; the cylindrical sample is divided into a series of concentric rings with the same width and thickness, the trapped field of the samples is the summation of magnetic field produced by all the rings, while the magnetic field generated by each ring was worked out by trapezoidal numerical integration based on the Biot Savart law with the critical current density Jc of the samples. It is found that the calculated field of the samples is well in agreement with the experimental results if the reasonable Jc of the samples is adopted. The theoretical calculation result also indicates that the larger the diameter and the thickness of the samples, the stronger the trapped flux density, but the optimal diameter/thickness ratio should be of a reasonable value around one, and it is not so good to fabricated samples with too larger diameter or thickness for practical applications.
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.
Three-Dimensional (3D) Distribution
2009-03-11
witnessed by ongoing efforts in both Afghanistan and Iraq , must turn distribution challenges into opportunities by mastering Three-Dimensional (3D...sustainment. 5 Joint Logistics Functions •Supply •Services •Maintenance •Transportation • Health Service Support •General Engineering Joint Personnel...Maintenance •Transportation • Health Service Support •Explosive Ordinance Disposal •Human Resource Support •Legal Support •Religious Support •Financial
Massively parallel implementation of 3D-RISM calculation with volumetric 3D-FFT.
Maruyama, Yutaka; Yoshida, Norio; Tadano, Hiroto; Takahashi, Daisuke; Sato, Mitsuhisa; Hirata, Fumio
2014-07-05
A new three-dimensional reference interaction site model (3D-RISM) program for massively parallel machines combined with the volumetric 3D fast Fourier transform (3D-FFT) was developed, and tested on the RIKEN K supercomputer. The ordinary parallel 3D-RISM program has a limitation on the number of parallelizations because of the limitations of the slab-type 3D-FFT. The volumetric 3D-FFT relieves this limitation drastically. We tested the 3D-RISM calculation on the large and fine calculation cell (2048(3) grid points) on 16,384 nodes, each having eight CPU cores. The new 3D-RISM program achieved excellent scalability to the parallelization, running on the RIKEN K supercomputer. As a benchmark application, we employed the program, combined with molecular dynamics simulation, to analyze the oligomerization process of chymotrypsin Inhibitor 2 mutant. The results demonstrate that the massive parallel 3D-RISM program is effective to analyze the hydration properties of the large biomolecular systems.
Kauweloa, Kevin I; Gutierrez, Alonso N; Stathakis, Sotirios; Papanikolaou, Niko; Mavroidis, Panayiotis
2016-07-01
A toolkit has been developed for calculating the 3-dimensional biological effective dose (BED) distributions in multi-phase, external beam radiotherapy treatments such as those applied in liver stereotactic body radiation therapy (SBRT) and in multi-prescription treatments. This toolkit also provides a wide range of statistical results related to dose and BED distributions. MATLAB 2010a, version 7.10 was used to create this GUI toolkit. The input data consist of the dose distribution matrices, organ contour coordinates, and treatment planning parameters from the treatment planning system (TPS). The toolkit has the capability of calculating the multi-phase BED distributions using different formulas (denoted as true and approximate). Following the calculations of the BED distributions, the dose and BED distributions can be viewed in different projections (e.g. coronal, sagittal and transverse). The different elements of this toolkit are presented and the important steps for the execution of its calculations are illustrated. The toolkit is applied on brain, head & neck and prostate cancer patients, who received primary and boost phases in order to demonstrate its capability in calculating BED distributions, as well as measuring the inaccuracy and imprecision of the approximate BED distributions. Finally, the clinical situations in which the use of the present toolkit would have a significant clinical impact are indicated. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
NASA Technical Reports Server (NTRS)
Ott, Lesley; Pickering, Kenneth; Stenchikov, Georgiy; Allen, Dale; DeCaria, Alex; Ridley, Brian; Lin, Ruei-Fong; Lang, Steve; Tao, Wei-Kuo
2009-01-01
A 3-D cloud scale chemical transport model that includes a parameterized source of lightning NO(x), based on observed flash rates has been used to simulate six midlatitude and subtropical thunderstorms observed during four field projects. Production per intracloud (P(sub IC) and cloud-to-ground (P(sub CG)) flash is estimated by assuming various values of P(sub IC) and P(sub CG) for each storm and determining which production scenario yields NO(x) mixing ratios that compare most favorably with in-cloud aircraft observations. We obtain a mean P(sub CG) value of 500 moles NO (7 kg N) per flash. The results of this analysis also suggest that on average, P(sub IC) may be nearly equal to P(sub CG), which is contrary to the common assumption that intracloud flashes are significantly less productive of NO than are cloud-to-ground flashes. This study also presents vertical profiles of the mass of lightning NO(x), after convection based on 3-D cloud-scale model simulations. The results suggest that following convection, a large percentage of lightning NO(x), remains in the middle and upper troposphere where it originated, while only a small percentage is found near the surface. The results of this work differ from profiles calculated from 2-D cloud-scale model simulations with a simpler lightning parameterization that were peaked near the surface and in the upper troposphere (referred to as a "C-shaped" profile). The new model results (a backward C-shaped profile) suggest that chemical transport models that assume a C-shaped vertical profile of lightning NO(x) mass may place too much mass neat the surface and too little in the middle troposphere.
NASA Astrophysics Data System (ADS)
Busse, Harald; Bublat, Martin; Ratering, Ralf; Rassek, Margarethe; Schwarzmaier, Hans-Joachim; Kahn, Thomas
2000-05-01
Minimally invasive techniques often require special biomedical monitoring schemes. In the case of laser coagulation of tumors accurate temperature mapping is desirable for therapy control. While magnetic resonance (MR)-based thermometry can easily yield qualitative results it is still difficult to calibrate this technique with independent temperature probes for the entire 2D field of view. Calculated temperature maps derived from Monte-Carlo simulations (MCS), on the other hand, are suitable for therapy planning and dosimetry but typically can not account for the extract individual tissue parameters and physiological changes upon heating. In this work, online thermometry was combined with MCS techniques to explore the feasibility and potential of such a biomodal approach for surgical assist systems. For the first time, the result of a 3D simulation were evaluated with MR techniques. An MR thermometry system was used to monitor the temperature evolution during laser-induced thermal treatment of bovine liver using a commercially available water-cooled applicator. A systematic comparison between MR-derived 2D temperature maps in different orientations and corresponding snapshots of a 3D MCS of the laser-induced processes is presented. The MCS is capable of resolving the complex temperature patterns observed in the MR-derived images and yields a good agreement with respect to absolute temperatures and damage volume dimensions. The observed quantitative agreement is around 10 degrees C and on the order of 10 percent, respectively. The integrated simulation-and-monitoring approach has the potential to improve surgical assistance during thermal interventions.
Application of DYNA3D in large scale crashworthiness calculations
Benson, D.J.; Hallquist, J.O.; Igarashi, M.; Shimomaki, K.; Mizuno, M.
1986-01-01
This paper presents an example of an automobile crashworthiness calculation. Based on our experiences with the example calculation, we make recommendations to those interested in performing crashworthiness calculations. The example presented in this paper was supplied by Suzuki Motor Co., Ltd., and provided a significant shakedown for the new large deformation shell capability of the DYNA3D code. 15 refs., 3 figs.
Multigrid calculations of 3-D turbulent viscous flows
NASA Technical Reports Server (NTRS)
Yokota, Jeffrey W.
1989-01-01
Convergence properties of a multigrid algorithm, developed to calculate compressible viscous flows, are analyzed by a vector sequence eigenvalue estimate. The full 3-D Reynolds-averaged Navier-Stokes equations are integrated by an implicit multigrid scheme while a k-epsilon turbulence model is solved, uncoupled from the flow equations. Estimates of the eigenvalue structure for both single and multigrid calculations are compared in an attempt to analyze the process as well as the results of the multigrid technique. The flow through an annular turbine is used to illustrate the scheme's ability to calculate complex 3-D flows.
Toutouzas, Konstantinos; Chatzizisis, Yiannis S; Riga, Maria; Giannopoulos, Andreas; Antoniadis, Antonios P; Tu, Shengxian; Fujino, Yusuke; Mitsouras, Dimitrios; Doulaverakis, Charalampos; Tsampoulatidis, Ioannis; Koutkias, Vassilis G; Bouki, Konstantina; Li, Yingguang; Chouvarda, Ioanna; Cheimariotis, Grigorios; Maglaveras, Nicos; Kompatsiaris, Ioannis; Nakamura, Sunao; Reiber, Johan H C; Rybicki, Frank; Karvounis, Haralambos; Stefanadis, Christodoulos; Tousoulis, Dimitris; Giannoglou, George D
2015-06-01
Geometrically-correct 3D OCT is a new imaging modality with the potential to investigate the association of local hemodynamic microenvironment with OCT-derived high-risk features. We aimed to describe the methodology of 3D OCT and investigate the accuracy, inter- and intra-observer agreement of 3D OCT in reconstructing coronary arteries and calculating ESS, using 3D IVUS and 3D QCA as references. 35 coronary artery segments derived from 30 patients were reconstructed in 3D space using 3D OCT. 3D OCT was validated against 3D IVUS and 3D QCA. The agreement in artery reconstruction among 3D OCT, 3D IVUS and 3D QCA was assessed in 3-mm-long subsegments using lumen morphometry and ESS parameters. The inter- and intra-observer agreement of 3D OCT, 3D IVUS and 3D QCA were assessed in a representative sample of 61 subsegments (n = 5 arteries). The data processing times for each reconstruction methodology were also calculated. There was a very high agreement between 3D OCT vs. 3D IVUS and 3D OCT vs. 3D QCA in terms of total reconstructed artery length and volume, as well as in terms of segmental morphometric and ESS metrics with mean differences close to zero and narrow limits of agreement (Bland-Altman analysis). 3D OCT exhibited excellent inter- and intra-observer agreement. The analysis time with 3D OCT was significantly lower compared to 3D IVUS. Geometrically-correct 3D OCT is a feasible, accurate and reproducible 3D reconstruction technique that can perform reliable ESS calculations in coronary arteries. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Recovering 3D particle size distributions from 2D sections
NASA Astrophysics Data System (ADS)
Cuzzi, Jeffrey N.; Olson, Daniel M.
2017-03-01
We discuss different ways to convert observed, apparent particle size distributions from 2D sections (thin sections, SEM maps on planar surfaces, etc.) into true 3D particle size distributions. We give a simple, flexible, and practical method to do this; show which of these techniques gives the most faithful conversions; and provide (online) short computer codes to calculate both 2D-3D recoveries and simulations of 2D observations by random sectioning. The most important systematic bias of 2D sectioning, from the standpoint of most chondrite studies, is an overestimate of the abundance of the larger particles. We show that fairly good recoveries can be achieved from observed size distributions containing 100-300 individual measurements of apparent particle diameter.
Automated liver elasticity calculation for 3D MRE
NASA Astrophysics Data System (ADS)
Dzyubak, Bogdan; Glaser, Kevin J.; Manduca, Armando; Ehman, Richard L.
2017-03-01
Magnetic Resonance Elastography (MRE) is a phase-contrast MRI technique which calculates quantitative stiffness images, called elastograms, by imaging the propagation of acoustic waves in tissues. It is used clinically to diagnose liver fibrosis. Automated analysis of MRE is difficult as the corresponding MRI magnitude images (which contain anatomical information) are affected by intensity inhomogeneity, motion artifact, and poor tissue- and edge-contrast. Additionally, areas with low wave amplitude must be excluded. An automated algorithm has already been successfully developed and validated for clinical 2D MRE. 3D MRE acquires substantially more data and, due to accelerated acquisition, has exacerbated image artifacts. Also, the current 3D MRE processing does not yield a confidence map to indicate MRE wave quality and guide ROI selection, as is the case in 2D. In this study, extension of the 2D automated method, with a simple wave-amplitude metric, was developed and validated against an expert reader in a set of 57 patient exams with both 2D and 3D MRE. The stiffness discrepancy with the expert for 3D MRE was -0.8% +/- 9.45% and was better than discrepancy with the same reader for 2D MRE (-3.2% +/- 10.43%), and better than the inter-reader discrepancy observed in previous studies. There were no automated processing failures in this dataset. Thus, the automated liver elasticity calculation (ALEC) algorithm is able to calculate stiffness from 3D MRE data with minimal bias and good precision, while enabling stiffness measurements to be fully reproducible and to be easily performed on the large 3D MRE datasets.
NASA Astrophysics Data System (ADS)
Harvey, R. W.; Petrov, Yu.; Jaeger, E. F.; Berry, L. A.; Bonoli, P. T.; Bader, A.
2015-12-01
A time-dependent simulation of C-Mod pulsed TCRF power is made obtaining minority hydrogen ion distributions with the CQL3D-Hybrid-FOW finite-orbit-width Fokker-Planck code. Cyclotron-resonant TCRF fields are calculated with the AORSA full wave code. The RF diffusion coefficients used in CQL3D are obtained with the DC Lorentz gyro-orbit code for perturbed particle trajectories in the combined equilibrium and TCRF electromagnetic fields. Prior results with a zero-banana-width simulation using the CQL3D/AORSA/DC time-cycles showed a pronounced enhancement of the H distribution in the perpendicular velocity direction compared to results obtained from Stix's quasilinear theory, and this substantially increased the rampup rate of the observed vertically-viewed neutral particle analyzer (NPA) flux, in general agreement with experiment. However, ramp down of the NPA flux after the pulse, remained long compared to the experiment. The present study compares the new FOW results, including relevant gyro-radius effects, to determine the importance of these new effects on the the NPA time-dependence.
3-D magnetic field calculations for wiggglers using MAGNUS-3D
Pissanetzky, S.; Tompkins, P.
1988-01-01
The recent but steady trend toward increased magnetic and geometric complexity in the design of wigglers and undulators, of which tapered wigglers, hybrid structures, laced electromagnetic wigglers, magnetic cladding, twisters and magic structures are examples, has caused a need for reliable 3-D computer models and a better understanding of the behavior of magnetic systems in three dimensions. The capabilities of the MAGNUS-3D Group of Programs are ideally suited to solve this class of problems and provide insight into 3-D effects. MAGNUS-3D can solve any problem of Magnetostatics involving permanent magnets, linear or nonlinear ferromagnetic materials and electric conductors of any shape in space. The magnetic properties of permanent magnets are described by the complete nonlinear demagnetization curve as provided by the manufacturer, or, at the user's choice, by a simpler approximation involving the coercive force, the residual induction and the direction of magnetization. The ferromagnetic materials are described by a magnetization table and an accurate interpolation relation. An internal library with properties of common industrial steels is available. The conductors are independent of the mesh and are described in terms of conductor elements from an internal library.
The CONV-3D code for DNS CFD calculation
NASA Astrophysics Data System (ADS)
Chudanov, Vladimir; ALCF ThermHydraX Team
2014-03-01
The CONV-3D code for DNS CFD calculation of thermal and hydrodynamics on Fast Reactor with use of supercomputers is developed. This code is highly effective in a scalability at the high performance computers such as ``Chebyshev'', ``Lomonosov'' (Moscow State University, Russia), Blue Gene/Q(ALCF MIRA, ANL). The scalability is reached up to 106 processors. The code was validated on a series of the well known tests in a wide range of Rayleigh (106-1016) and Reynolds (103-105. Such code was validated on the blind tests OECD/NEA of the turbulent intermixing in horizontal subchannels of the fuel assembly at normal pressure and temperature (Matis-H), of the flows in T-junction and the report IBRAE/ANL was published. The good coincidence of numerical predictions with experimental data was reached, that specifies applicability of the developed approach for a prediction of thermal and hydrodynamics in a boundary layer at small Prandtl that is characteristic of the liquid metal reactors. Project Name: ThermHydraX. Project Title: U.S.-Russia Collaboration on Cross-Verification and Validation in Thermal Hydraulics.
Prostate Mechanical Imaging: 3-D Image Composition and Feature Calculations
Egorov, Vladimir; Ayrapetyan, Suren; Sarvazyan, Armen P.
2008-01-01
We have developed a method and a device entitled prostate mechanical imager (PMI) for the real-time imaging of prostate using a transrectal probe equipped with a pressure sensor array and position tracking sensor. PMI operation is based on measurement of the stress pattern on the rectal wall when the probe is pressed against the prostate. Temporal and spatial changes in the stress pattern provide information on the elastic structure of the gland and allow two-dimensional (2-D) and three-dimensional (3-D) reconstruction of prostate anatomy and assessment of prostate mechanical properties. The data acquired allow the calculation of prostate features such as size, shape, nodularity, consistency/hardness, and mobility. The PMI prototype has been validated in laboratory experiments on prostate phantoms and in a clinical study. The results obtained on model systems and in vivo images from patients prove that PMI has potential to become a diagnostic tool that could largely supplant DRE through its higher sensitivity, quantitative record storage, ease-of-use and inherent low cost. PMID:17024836
NASA Astrophysics Data System (ADS)
Lokajíček, T.; Kern, H.; Svitek, T.; Ivankina, T.
2014-06-01
Ultrasonic measurements of the 3D velocity distribution of P- and S-waves were performed on a spherical sample of a biotite gneiss from the Outokumpu scientific drill hole. Measurements were done at room temperature and pressures up to 400 and 70 MPa, respectively, in a pressure vessel with oil as a pressure medium. A modified transducer/sample assembly and the installation of a new mechanical system allowed simultaneous measurements of P- and S-wave velocities in 132 independent directions of the sphere on a net in steps of 15°. Proper signals for P- and S-waves could be recorded by coating the sample surface with a high-viscosity shear wave gel and by temporal point contacting of the transmitter and receiver transducers with the sample surface during the measurements. The 3D seismic measurements revealed a strong foliation-related directional dependence (anisotropy) of P- and S-wave velocities, which is confirmed by measurements in a multi-anvil apparatus on a cube-shaped specimen of the same rock. Both experimental approaches show a marked pressure sensitivity of P- and S-wave velocities and velocity anisotropies. With increasing pressure, P- and S-wave velocities increase non-linearly due to progressive closure of micro-cracks. The reverse is true for velocity anisotropy. 3D velocity calculations based on neutron diffraction measurements of crystallographic preferred orientation (CPO) of major minerals show that the intrinsic bulk anisotropy is basically caused by the CPO of biotite constituting about 23 vol.% of the rock. Including the shape of biotite grains and oriented low-aspect ratio microcracks into the modelling increases bulk anisotropy. An important finding from this study is that the measurements on the sample sphere and on the sample cube displayed distinct differences, particularly in shear wave velocities. It is assumed that the differences are due to the different geometries of the samples and the configuration of the transducer-sample assembly
3D calculation of boiling in complex geometry of steam generator
Ravnikar, I.; Petelin, S.
1996-11-01
The D4 steam generator of nuclear power plant Krsko was analyzed from a thermal-hydraulic point of view using the 3D PHOENICS computer code. The calculations were carried out for different operating conditions based on plugging study that was performed using 1D steam generator model SMUP computer code. Void fraction, velocity and enthalpy distributions were then obtained in the U-tube riser section.
Calculating Least Risk Paths in 3d Indoor Space
NASA Astrophysics Data System (ADS)
Vanclooster, A.; De Maeyer, Ph.; Fack, V.; Van de Weghe, N.
2013-08-01
Over the last couple of years, research on indoor environments has gained a fresh impetus; more specifically applications that support navigation and wayfinding have become one of the booming industries. Indoor navigation research currently covers the technological aspect of indoor positioning and the modelling of indoor space. The algorithmic development to support navigation has so far been left mostly untouched, as most applications mainly rely on adapting Dijkstra's shortest path algorithm to an indoor network. However, alternative algorithms for outdoor navigation have been proposed adding a more cognitive notion to the calculated paths and as such adhering to the natural wayfinding behaviour (e.g. simplest paths, least risk paths). These algorithms are currently restricted to outdoor applications. The need for indoor cognitive algorithms is highlighted by a more challenged navigation and orientation due to the specific indoor structure (e.g. fragmentation, less visibility, confined areas…). As such, the clarity and easiness of route instructions is of paramount importance when distributing indoor routes. A shortest or fastest path indoors not necessarily aligns with the cognitive mapping of the building. Therefore, the aim of this research is to extend those richer cognitive algorithms to three-dimensional indoor environments. More specifically for this paper, we will focus on the application of the least risk path algorithm of Grum (2005) to an indoor space. The algorithm as proposed by Grum (2005) is duplicated and tested in a complex multi-storey building. The results of several least risk path calculations are compared to the shortest paths in indoor environments in terms of total length, improvement in route description complexity and number of turns. Several scenarios are tested in this comparison: paths covering a single floor, paths crossing several building wings and/or floors. Adjustments to the algorithm are proposed to be more aligned to the
Eigenvalue Contributon Estimator for Sensitivity Calculations with TSUNAMI-3D
Rearden, Bradley T; Williams, Mark L
2007-01-01
Since the release of the Tools for Sensitivity and Uncertainty Analysis Methodology Implementation (TSUNAMI) codes in SCALE [1], the use of sensitivity and uncertainty analysis techniques for criticality safety applications has greatly increased within the user community. In general, sensitivity and uncertainty analysis is transitioning from a technique used only by specialists to a practical tool in routine use. With the desire to use the tool more routinely comes the need to improve the solution methodology to reduce the input and computational burden on the user. This paper reviews the current solution methodology of the Monte Carlo eigenvalue sensitivity analysis sequence TSUNAMI-3D, describes an alternative approach, and presents results from both methodologies.
3-D adaptive grid Navier-Stokes rocket plume calculations
NASA Astrophysics Data System (ADS)
Holcomb, J. Eric
1991-01-01
Three-dimensional adaptive-grid full Navier-Stokes calculations performed for the base region and plume of the Minuteman first stage and a simplified version of the Titan first stage are used to demonstrate the applicability of the Navier-Stokes flow solver, EAGLE adaptive grid generator, and k-epsilon turbulence model to rocket plume flowfields. The calculations include realistic exhaust gas thermodynamic properties, with frozen chemistry.
3D Game Content Distributed Adaptation in Heterogeneous Environments
NASA Astrophysics Data System (ADS)
Morán, Francisco; Preda, Marius; Lafruit, Gauthier; Villegas, Paulo; Berretty, Robert-Paul
2007-12-01
Most current multiplayer 3D games can only be played on a single dedicated platform (a particular computer, console, or cell phone), requiring specifically designed content and communication over a predefined network. Below we show how, by using signal processing techniques such as multiresolution representation and scalable coding for all the components of a 3D graphics object (geometry, texture, and animation), we enable online dynamic content adaptation, and thus delivery of the same content over heterogeneous networks to terminals with very different profiles, and its rendering on them. We present quantitative results demonstrating how the best displayed quality versus computational complexity versus bandwidth tradeoffs have been achieved, given the distributed resources available over the end-to-end content delivery chain. Additionally, we use state-of-the-art, standardised content representation and compression formats (MPEG-4 AFX, JPEG 2000, XML), enabling deployment over existing infrastructure, while keeping hooks to well-established practices in the game industry.
ICRF Antenna Characteristics and Comparison with 3-D Code Calculation in the LHD
Mutoh, T.; Kasahara, H.; Seki, T.; Saito, K.; Kumazawa, R.; Shimpo, F.; Nomura, G.
2009-11-26
The plasma coupling characteristics and local heat spots of an ion cyclotron range of frequencies (ICRF) antenna in the Large Helical Device (LHD) are compared with the results of 3-D computing simulator code calculation. We studied several dependences of antenna loading resistances with plasma experimentally and observed a clear relation between the maximum injection power and the loading resistance. Realistic three-dimensional configuration of the ICRF antenna was taken into account to simulate the coupling characteristics and the local heat absorption near the ICRF antenna, which has a helically twisted geometry in the LHD. The electromagnetic field distribution and the current distribution on the antenna strap were calculated. We compared the RF absorption distribution on the antenna structure with the temperature rise during steady state operation and found that the temperature rise was well explained by comparing with the model simulation.
3D Hail Size Distribution Interpolation/Extrapolation Algorithm
NASA Technical Reports Server (NTRS)
Lane, John
2013-01-01
Radar data can usually detect hail; however, it is difficult for present day radar to accurately discriminate between hail and rain. Local ground-based hail sensors are much better at detecting hail against a rain background, and when incorporated with radar data, provide a much better local picture of a severe rain or hail event. The previous disdrometer interpolation/ extrapolation algorithm described a method to interpolate horizontally between multiple ground sensors (a minimum of three) and extrapolate vertically. This work is a modification to that approach that generates a purely extrapolated 3D spatial distribution when using a single sensor.
Olson, Gordon Lee
2016-12-06
Here, gray and multigroup radiation is transported through 3D media consisting of spheres randomly placed in a uniform background. Comparisons are made between using constant radii spheres and three different distributions of sphere radii. Because of the computational cost of 3D calculations, only the lowest angle order, n=1, is tested. If the mean chord length is held constant, using different radii distributions makes little difference. This is true for both gray and multigroup solutions. 3D transport solutions are compared to 2D and 1D solutions with the same mean chord lengths. 2D disk and 3D sphere media give solutions that aremore » nearly identical while 1D slab solutions are fundamentally different.« less
Olson, Gordon Lee
2016-12-06
Here, gray and multigroup radiation is transported through 3D media consisting of spheres randomly placed in a uniform background. Comparisons are made between using constant radii spheres and three different distributions of sphere radii. Because of the computational cost of 3D calculations, only the lowest angle order, n=1, is tested. If the mean chord length is held constant, using different radii distributions makes little difference. This is true for both gray and multigroup solutions. 3D transport solutions are compared to 2D and 1D solutions with the same mean chord lengths. 2D disk and 3D sphere media give solutions that are nearly identical while 1D slab solutions are fundamentally different.
NASA Astrophysics Data System (ADS)
Olson, Gordon L.
2017-03-01
Gray and multigroup radiation is transported through 3D media consisting of spheres randomly placed in a uniform background. Comparisons are made between using constant radii spheres and three different distributions of sphere radii. Because of the computational cost of 3D calculations, only the lowest angle order, n=1, is tested. If the mean chord length is held constant, using different radii distributions makes little difference. This is true for both gray and multigroup solutions. 3D transport solutions are compared to 2D and 1D solutions with the same mean chord lengths. 2D disk and 3D sphere media give solutions that are nearly identical while 1D slab solutions are fundamentally different.
3D Neutron Transport PWR Full-core Calculation with RMC code
NASA Astrophysics Data System (ADS)
Qiu, Yishu; She, Ding; Fan, Xiao; Wang, Kan; Li, Zeguang; Liang, Jingang; Leroyer, Hadrien
2014-06-01
Nowadays, there are more and more interests in the use of Monte Carlo codes to calculate the detailed power density distributions in full-core reactors. With the Inspur TS1000 HPC Server of Tsinghua University, several calculations have been done based on the EDF 3D Neutron Transport PWR Full-core benchmark through large-scale parallelism. To investigate and compare the results of the deterministic method and Monte Carlo method, EDF R&D and Department of Engineering Physics of Tsinghua University are having a collaboration to make code to code verification. So in this paper, two codes are used. One is the code COCAGNE developed by the EDF R&D, a deterministic core code, and the other is the Monte Carlo code RMC developed by Department of Engineering Physics in Tsinghua University. First, the full-core model is described and a 26-group calculation was performed by these two codes using the same 26-group cross-section library provided by EDF R&D. Then the parallel and tally performance of RMC is discussed. RMC employs a novel algorithm which can cut down most of the communications. It can be seen clearly that the speedup ratio almost linearly increases with the nodes. Furthermore the cell-mapping method applied by RMC consumes little time to tally even millions of cells. The results of the codes COCAGNE and RMC are compared in three ways. The results of these two codes agree well with each other. It can be concluded that both COCAGNE and RMC are able to provide 3D-transport solutions associated with detailed power density distributions calculation in PWR full-core reactors. Finally, to investigate how many histories are needed to obtain a given standard deviation for a full 3D solution, the non-symmetrized condensed 2-group fluxes of RMC are discussed.
3D crack aperture distribution from a nuclear imaging method
NASA Astrophysics Data System (ADS)
Sardini, Paul; Kuva, Jukka; Siitari-Kauppi, Marja; Bonnet, Marine; Hellmuth, Karl-Heinz
2017-04-01
Cracks in solid rocks are multi-scale entities because of their spatial, length and aperture distributions. Aperture distributions of cracks are not well known because their full aperture range (<0.1 µm to >1 mm) is not accessible using common imaging techniques, such as SEM or X-Ray computed micro-tomography. Knowing the aperture distribution or cracks is, however, highly relevant to understanding flow in rocks. In crystalline rocks the lack of knowledge about the crack aperture distribution keeps us from a clear understanding of the relationships of porosity and permeability. A nuclear imaging method based on the full saturation of connected rock porosity by a 14C-doped resin (the 14-C PMMA method) allows detecting the connected microcrack network using autoradiography. Even if cracks are detected only on 2D sections, an estimate of the 3D aperture distribution of these cracks is possible. To this end, a set of "artificial crack" standards was prepared and investigated. These standards consisted of a PMMA layer of known thickness between two glass plates. Analysis of experimental autoradiographic profiles around these artificial cracks allows determination of their aperture. This methodology was then applied to different rock samples, mainly granitic ones.
Angular distribution of Auger electrons due to 3d-shell impact ionization of krypton
NASA Technical Reports Server (NTRS)
Omidvar, K.
1977-01-01
Cross sections for electron impact ionization of krypton due to ejection of a 3d-shell electron have been calculated using screened hydrogenic and Hartree-Slater wavefunctions for the target atom. While the total ionization cross sections in the two approximations are within 10% of each other, the Auger electron angular distribution, related to cross sections for specific magnetic quantum numbers of the 3d electrons, are widely different in the two approximations. The angular distribution due to the Hartree-Slater approximation is in excellent agreement with measurement. The physical reason for the discrepancies in the two approximations is explained.
Scalable Multi-Platform Distribution of Spatial 3d Contents
NASA Astrophysics Data System (ADS)
Klimke, J.; Hagedorn, B.; Döllner, J.
2013-09-01
Virtual 3D city models provide powerful user interfaces for communication of 2D and 3D geoinformation. Providing high quality visualization of massive 3D geoinformation in a scalable, fast, and cost efficient manner is still a challenging task. Especially for mobile and web-based system environments, software and hardware configurations of target systems differ significantly. This makes it hard to provide fast, visually appealing renderings of 3D data throughout a variety of platforms and devices. Current mobile or web-based solutions for 3D visualization usually require raw 3D scene data such as triangle meshes together with textures delivered from server to client, what makes them strongly limited in terms of size and complexity of the models they can handle. In this paper, we introduce a new approach for provisioning of massive, virtual 3D city models on different platforms namely web browsers, smartphones or tablets, by means of an interactive map assembled from artificial oblique image tiles. The key concept is to synthesize such images of a virtual 3D city model by a 3D rendering service in a preprocessing step. This service encapsulates model handling and 3D rendering techniques for high quality visualization of massive 3D models. By generating image tiles using this service, the 3D rendering process is shifted from the client side, which provides major advantages: (a) The complexity of the 3D city model data is decoupled from data transfer complexity (b) the implementation of client applications is simplified significantly as 3D rendering is encapsulated on server side (c) 3D city models can be easily deployed for and used by a large number of concurrent users, leading to a high degree of scalability of the overall approach. All core 3D rendering techniques are performed on a dedicated 3D rendering server, and thin-client applications can be compactly implemented for various devices and platforms.
Elemental concentration distribution in human fingernails - A 3D study
NASA Astrophysics Data System (ADS)
Pineda-Vargas, C. A.; Mars, J. A.; Gihwala, D.
2012-02-01
The verification of pathologies has normally been based on analysis of blood (serum and plasma), and physiological tissue. Recently, nails and in particular human fingernails have become an important medium for pathological studies, especially those of environmental origin. The analytical technique of PIXE has been used extensively in the analysis of industrial samples and human tissue specimens. The application of the analytical technique to nails has been mainly to bulk samples. In this study we use micro-PIXE and -RBS, as both complementary and supplementary, to determine the elemental concentration distribution of human fingernails of individuals. We report on the 3D quantitative elemental concentration distributions (QECDs) of various elements that include C, N and O as major elements (10-20%), P, S, Cl, K and Ca as minor elements (1-10%) and Fe, Mn, Zn, Ti, Na, Mg, Cu, Ni, Cr, Rb, Br, Sr and Se as trace elements (less than 1%). For PIXE and RBS the specimens were bombarded with a 3 MeV proton beam. To ascertain any correlations in the quantitative elemental concentration distributions, a linear traverse analysis was performed across the width of the nail. Elemental distribution correlations were also obtained.
Joint distributed source-channel coding for 3D videos
NASA Astrophysics Data System (ADS)
Palma, Veronica; Cancellaro, Michela; Neri, Alessandro
2011-03-01
This paper presents a distributed joint source-channel 3D video coding system. Our aim is the design of an efficient coding scheme for stereoscopic video communication over noisy channels that preserves the perceived visual quality while guaranteeing a low computational complexity. The drawback in using stereo sequences is the increased amount of data to be transmitted. Several methods are being used in the literature for encoding stereoscopic video. A significantly different approach respect to traditional video coding has been represented by Distributed Video Coding (DVC), which introduces a flexible architecture with the design of low complex video encoders. In this paper we propose a novel method for joint source-channel coding in a distributed approach. We choose turbo code for our application and study the new setting of distributed joint source channel coding of a video. Turbo code allows to send the minimum amount of data while guaranteeing near channel capacity error correcting performance. In this contribution, the mathematical framework will be fully detailed and tradeoff among redundancy and perceived quality and quality of experience will be analyzed with the aid of numerical experiments.
An efficient 3D traveltime calculation using coarse-grid mesh for shallow-depth source
NASA Astrophysics Data System (ADS)
Son, Woohyun; Pyun, Sukjoon; Lee, Ho-Young; Koo, Nam-Hyung; Shin, Changsoo
2016-10-01
3D Kirchhoff pre-stack depth migration requires an efficient algorithm to compute first-arrival traveltimes. In this paper, we exploited a wave-equation-based traveltime calculation algorithm, which is called the suppressed wave equation estimation of traveltime (SWEET), and the equivalent source distribution (ESD) algorithm. The motivation of using the SWEET algorithm is to solve the Laplace-domain wave equation using coarse grid spacing to calculate first-arrival traveltimes. However, if a real source is located at shallow-depth close to free surface, we cannot accurately calculate the wavefield using coarse grid spacing. So, we need an additional algorithm to correctly simulate the shallow source even for the coarse grid mesh. The ESD algorithm is a method to define a set of distributed nodal sources that approximate a point source at the inter-nodal location in a velocity model with large grid spacing. Thanks to the ESD algorithm, we can efficiently calculate the first-arrival traveltimes of waves emitted from shallow source point even when we solve the Laplace-domain wave equation using a coarse-grid mesh. The proposed algorithm is applied to the SEG/EAGE 3D salt model. From the result, we note that the combination of SWEET and ESD algorithms can be successfully used for the traveltime calculation under the condition of a shallow-depth source. We also confirmed that our algorithm using coarse-grid mesh requires less computational time than the conventional SWEET algorithm using relatively fine-grid mesh.
Distributed deformation and block rotation in 3D
NASA Technical Reports Server (NTRS)
Scotti, Oona; Nur, Amos; Estevez, Raul
1990-01-01
The authors address how block rotation and complex distributed deformation in the Earth's shallow crust may be explained within a stationary regional stress field. Distributed deformation is characterized by domains of sub-parallel fault-bounded blocks. In response to the contemporaneous activity of neighboring domains some domains rotate, as suggested by both structural and paleomagnetic evidence. Rotations within domains are achieved through the contemporaneous slip and rotation of the faults and of the blocks they bound. Thus, in regions of distributed deformation, faults must remain active in spite of their poor orientation in the stress field. The authors developed a model that tracks the orientation of blocks and their bounding faults during rotation in a 3D stress field. In the model, the effective stress magnitudes of the principal stresses (sigma sub 1, sigma sub 2, and sigma sub 3) are controlled by the orientation of fault sets in each domain. Therefore, adjacent fault sets with differing orientations may be active and may display differing faulting styles, and a given set of faults may change its style of motion as it rotates within a stationary stress regime. The style of faulting predicted by the model depends on a dimensionless parameter phi = (sigma sub 2 - sigma sub 3)/(sigma sub 1 - sigma sub 3). Thus, the authors present a model for complex distributed deformation and complex offset history requiring neither geographical nor temporal changes in the stress regime. They apply the model to the Western Transverse Range domain of southern California. There, it is mechanically feasible for blocks and faults to have experienced up to 75 degrees of clockwise rotation in a phi = 0.1 strike-slip stress regime. The results of the model suggest that this domain may first have accommodated deformation along preexisting NNE-SSW faults, reactivated as normal faults. After rotation, these same faults became strike-slip in nature.
Calculation of Dose Deposition in 3D Voxels by Heavy Ions
NASA Technical Reports Server (NTRS)
Plante, Ianik; Cucinotta, Francis A.
2010-01-01
The biological response to high-LET radiation is very different from low-LET radiation, and can be partly attributed to the energy deposition by the radiation. Several experiments, notably detection of gamma-H2AX foci by immunofluorescence, has revealed important differences in the nature and in the spatial distribution of double-strand breaks (DSB) induced by low- and high-LET radiations. Many calculations, most of which are based on amorphous track models with radial dose, have been combined with chromosome models to calculate the number and distribution of DSB within nuclei and chromosome aberrations. In this work, the Monte-Carlo track structure simulation code RITRACKS have been used to calculate directly the energy deposition in voxels (3D pixels). A cubic volume of 5 micrometers of side was irradiated by 1) 450 (1)H+ ions of 300 MeV (LET is approximately 0.3 keV/micrometer) and 2) by 1 (56)Fe26+ ion of 1 GeV/amu (LET is approximately 150 keV/micrometer). In both cases, the dose deposited in the volume is approximately 1 Gy. All energy deposition events are recorded and dose is calculated in voxels of 20 micrometers of side. The voxels are then visualized in 3D by using a color scale to represent the intensity of the dose in a voxel. This simple approach has revealed several important points which may help understand experimental observations. In both simulations, voxels which receive low dose are the most numerous, and those corresponding to electron track ends received a dose which is in the higher range. The dose voxels are distributed randomly and scattered uniformly within the volume irradiated by low-LET radiation. The distribution of the voxels shows major differences for the (56)Fe26+ ion. The track structure can still be seen, and voxels with much higher dose are found in the region corresponding to the track "core". These high-dose voxels are not found in the low-LET irradiation simulation and may be responsible for DSB that are more difficult to
Simultaneous calculation of three optical surfaces in the 3D SMS freeform RXI optic
NASA Astrophysics Data System (ADS)
Sorgato, Simone; Chaves, Julio; Mohedano, Rubén.; Hernández, Maikel; Blen, José; Benitez, Pablo; Miñano, Juan C.; Grabovickic, Dejan; Thienpont, Hugo; Duerr, Fabian
2016-09-01
The Freeform RXI collimator is a remarkable example of advanced nonimaging device designed with the 3D Simultaneous Multiple Surface (SMS) Method. In the original design, two (the front refracting surface and the back mirror) of the three optical surfaces of the RXI are calculated simultaneously and one (the cavity surrounding the source) is fixed by the designer. As a result, the RXI perfectly couples two input wavefronts (coming from the edges of the extended LED source) with two output wavefronts (defining the output beam). This allows for LED lamps able to produce controlled intensity distributions, which can and have been successfully applied to demanding applications like high- and low-beams for Automotive Lighting. Nevertheless, current trends in this field are moving towards smaller headlamps with more shape constraints driven by car design. We present an improved version of the 3D RXI in which also the cavity surface is computed during the design, so that there are three freeform surfaces calculated simultaneously and an additional degree of freedom for controlling the light emission: now the RXI can perfectly couple three input wavefronts with three output wavefronts. The enhanced control over ray beams allows for improved light homogeneity and better pattern definition.
CARd-3D: Carbon Distribution in 3D Structure Program for Globular Proteins.
Ekambaram, Rajasekaran; Kannaiyan, Akila; Marimuthu, Vijayasarathy; Swaminathan, Vinobha Chinnaiah; Renganathan, Senthil; Perumal, Ananda Gopu
2014-01-01
Spatial arrangement of carbon in protein structure is analyzed here. Particularly, the carbon fractions around individual atoms are compared. It is hoped that it follows the principle of 31.45% carbon around individual atoms. The results reveal that globular protein's atoms follow this principle. A comparative study on monomer versus dimer reveal that carbon is better distributed in dimeric form than in its monomeric form. Similar study on solid versus liquid structures reveals that the liquid (NMR) structure has better carbon distribution over the corresponding solid (X-Ray) structure. The carbon fraction distributions in fiber and toxin protein are compared. Fiber proteins follow the principle of carbon fraction distribution. At the same time it has another broad spectrum of carbon distribution than in globular proteins. The toxin protein follows an abnormal carbon fraction distribution. The carbon fraction distribution plays an important role in deciding the structure and shape of proteins. It is hoped to help in understanding the protein folding and function.
NASA Astrophysics Data System (ADS)
Badawi, R. D.; Lodge, M. A.; Marsden, P. K.
1998-01-01
Accurate normalization of lines of response in 3D PET is a prerequisite for quantitative reconstruction. Most current methods are component based, calculating a series of geometric and intrinsic detector efficiency factors. We have reviewed the theory behind several existing algorithms for calculating detector efficiency factors in 2D and 3D PET, and have extended them to create a range of new algorithms. Three of the algorithms described are `fully 3D' in that they make use of data from all detector rings for the calculation of the efficiencies of any one line of response. We have assessed the performance of the new and existing methods using simulated and real data, and have demonstrated that the fully 3D algorithms allow the rapid acquisition of crystal efficiency normalization data using low-activity sources. Such methods enable the use of scatter-free scanning line sources or the use of very short acquisitions of cylindrical sources for routine normalization.
3D concentration distributions of ion implants in amorphous solids
NASA Astrophysics Data System (ADS)
Günzler, R.; Weiser, M.; Kalbitz, S.
1992-01-01
Spatial distributions of implanted ions have been derived from depth profiles of implants at varied incidence angle by applying tomographic techniques. To this end we have developed a new version of an algorithm known as simultaneous iterative reconstruction technique (SIRT), which covers the experimental concentration range of about three decades. In addition, the finite depth resolution of the nuclear reaction analysis (NRA) is accounted for in our computer program. In this way, we have reconstructed the three-dimensional implantation distributions of 0.15 MeV 1H, 1.5 and 6 MeV 15N, and 4 MeV 30Si in amorphized Ge layers. The agreement with TRIM calculations is reasonable: 10% ± 0.5% for the first and 10% ± 5% for the second range moments. Consequences of the longitudinal and lateral tailing for ion beam applications to large scale integration problems are discussed.
NASA Astrophysics Data System (ADS)
Svoboda, O.; Bach, P.; Yang, J.; Wang, C.
2006-11-01
In a real machine shop environment and under various spindle loads, the machine thermal expansion may cause large 3D volumetric positioning errors. With an intelligent controller, it is possible to compensate these errors provide that the relations between the 3D volumetric positioning errors and the temperature distribution were measured. A laser vector measurement technique developed by Optodyne was used for a quick measurement of 3D volumetric positioning errors of a CNC machining center under various spindle loads, machine movement and ambient conditions. Correlation calculations were used to determine the key temperatures and the various positioning errors. Preliminary results showed that large machine temperature changes caused somewhat small straightness error changes but large squareness error changes. Using the measured position errors, several error maps could be generated. Compensation tables at an actual thermal state can be interpolated to achieve higher accuracy at various thermal loadings.
Sando, Yusuke; Barada, Daisuke; Yatagai, Toyohiko
2012-09-10
We have derived the basic spectral relation between a 3-D object and its 2-D diffracted wavefront by interpreting the diffraction calculation in the 3-D Fourier domain. Information on the 3-D object, which is inherent in the diffracted wavefront, becomes clear by using this relation. After the derivation, a method for obtaining the Fourier spectrum that is required to synthesize a hologram with a realistic sampling number for visible light is described. Finally, to verify the validity and the practicality of the above-mentioned spectral relation, fast calculation of a series of wavefronts radially diffracted from a 3-D voxel-based object is demonstrated.
New approach on calculating multiview 3D crosstalk for autostereoscopic displays
NASA Astrophysics Data System (ADS)
Jung, Sung-Min; Lee, Kyeong-Jin; Kang, Ji-Na; Lee, Seung-Chul; Lim, Kyoung-Moon
2012-03-01
In this study, we suggest a new concept of 3D crosstalk for auto-stereoscopic displays and obtain 3D crosstalk values of several multi-view systems based on the suggested definition. First, we measure the angular dependencies of the luminance for auto-stereoscopic displays under various test patterns corresponding to each view of a multi-view system and then calculate the 3D crosstalk based on our new definition with respect to the measured luminance profiles. Our new approach gives just a single 3D crosstalk value for single device without any ambiguity and shows similar order of values to the conventional stereoscopic displays. These results are compared with the conventional 3D crosstalk values of selected auto-stereoscopic displays such as 4-view and 9-view systems. From the result, we believe that this new approach is very useful for controlling 3D crosstalk values of the 3D displays manufacturing and benchmarking of the 3D performances among the various auto-stereoscopic displays.
A Cross-Benchmarking and Validation Initiative for Tokamak 3D Equilibrium Calculations
NASA Astrophysics Data System (ADS)
Reiman, A.; Turnbull, A.; Evans, T.; Ferraro, N.; Lazarus, E.; Breslau, J.; Cerfon, A.; Chang, C. S.; Hager, R.; King, J.; Lanctot, M.; Lazerson, S.; Liu, Y.; McFadden, G.; Monticello, D.; Nazikian, R.; Park, J. K.; Sovinec, C.; Suzuki, Y.; Zhu, P.
2014-10-01
We are pursuing a cross-benchmarking and validation initiative for tokamak 3D equilibrium calculations, with 11 codes participating: the linearized tokamak equilibrium codes IPEC and MARS-F, the time-dependent extended MHD codes M3D-C1, M3D, and NIMROD, the gyrokinetic code XGC, as well as the stellarator codes VMEC, NSTAB, PIES, HINT and SPEC. Dedicated experiments for the purpose of generating data for validation have been done on the DIII-D tokamak. The data will allow us to do validation simultaneously with cross-benchmarking. Initial cross-benchmarking calculations are finding a disagreement between stellarator and tokamak 3D equilibrium codes. Work supported in part by U.S. DOE under Contracts DE-ACO2-09CH11466, DE-FC02-04E854698, DE-FG02-95E854309 and DE-AC05-000R22725.
Quantitative quality measure based on light wave distribution to access 3D display
NASA Astrophysics Data System (ADS)
Sakamoto, Yuji; Okuyama, Fumio
2011-02-01
There are a lot of three-dimensional (3D) displaying methods such as stereoscopy, integral photography, holography, etc. These technologies have different 3D vision properties and 3D image qualities. Conventionally, biological responsiveness is measured by using an actual 3D display in order to evaluate image qualities of 3D displaying method. It is required quantitative quality measure for 3D images for quantitative evaluation, which are useful for comparing 3D image quality and a design of a new display system. In this paper, we propose quality measures for 3D images named volume signal to noise ratio (VSNR), which is a three-dimensionally extended signal to noise ratio (SNR). A 3D display produces light wave distributions in 3D space, which makes observers view 3D image illusions. The VSNR measures error of light wave distributions between generated by actual objects and produced by a 3D display. The light wave distribution is including various factors for 3D perception of human such as resolution of reconstructed images, visual fields, motion parallax, and depth of field. The VSNR evaluates these 3D perception factors totally. We were carried out the experiments to certificate the efficiency of the VSNR. 3D images represented electro-holographic display and integral photographic displays were evaluated by the VSNR. The results indicated that the electro-holographic display has better quality than integral photographic display, but speckle noise deteriorates the 3D image quality.
Continuous-energy eigenvalue sensitivity coefficient calculations in TSUNAMI-3D
Perfetti, C. M.; Rearden, B. T.
2013-07-01
Two methods for calculating eigenvalue sensitivity coefficients in continuous-energy Monte Carlo applications were implemented in the KENO code within the SCALE code package. The methods were used to calculate sensitivity coefficients for several test problems and produced sensitivity coefficients that agreed well with both reference sensitivities and multigroup TSUNAMI-3D sensitivity coefficients. The newly developed CLUTCH method was observed to produce sensitivity coefficients with high figures of merit and a low memory footprint, and both continuous-energy sensitivity methods met or exceeded the accuracy of the multigroup TSUNAMI-3D calculations. (authors)
Zhu, Jinhan; Chen, Lixin; Chen, Along; Luo, Guangwen; Deng, Xiaowu; Liu, Xiaowei
2015-04-11
To use a graphic processing unit (GPU) calculation engine to implement a fast 3D pre-treatment dosimetric verification procedure based on an electronic portal imaging device (EPID). The GPU algorithm includes the deconvolution and convolution method for the fluence-map calculations, the collapsed-cone convolution/superposition (CCCS) algorithm for the 3D dose calculations and the 3D gamma evaluation calculations. The results of the GPU-based CCCS algorithm were compared to those of Monte Carlo simulations. The planned and EPID-based reconstructed dose distributions in overridden-to-water phantoms and the original patients were compared for 6 MV and 10 MV photon beams in intensity-modulated radiation therapy (IMRT) treatment plans based on dose differences and gamma analysis. The total single-field dose computation time was less than 8 s, and the gamma evaluation for a 0.1-cm grid resolution was completed in approximately 1 s. The results of the GPU-based CCCS algorithm exhibited good agreement with those of the Monte Carlo simulations. The gamma analysis indicated good agreement between the planned and reconstructed dose distributions for the treatment plans. For the target volume, the differences in the mean dose were less than 1.8%, and the differences in the maximum dose were less than 2.5%. For the critical organs, minor differences were observed between the reconstructed and planned doses. The GPU calculation engine was used to boost the speed of 3D dose and gamma evaluation calculations, thus offering the possibility of true real-time 3D dosimetric verification.
Efficient calculation method for realistic deep 3D scene hologram using orthographic projection
NASA Astrophysics Data System (ADS)
Igarashi, Shunsuke; Nakamura, Tomoya; Matsushima, Kyoji; Yamaguchi, Masahiro
2016-03-01
We propose a fast calculation method to synthesize a computer-generated hologram (CGH) of realistic deep three-dimensional (3D) scene. In our previous study, we have proposed a calculation method of CGH for reproducing such scene called ray-sampling-plane (RSP) method, in which light-ray information of a scene is converted to wavefront, and the wavefront is numerically propagated based on diffraction theory. In this paper, we introduce orthographic projection to the RSP method for accelerating calculation time. By numerical experiments, we verified the accelerated calculation with the ratio of 28-times compared to the conventional RSP method. The calculated CGH was fabricated by the printing system using laser lithography and demonstrated deep 3D image reconstruction in 52mm×52mm with realistic appearance effect such as gloss and translucent effect.
New data-driven method from 3D confocal microscopy for calculating phytoplankton cell biovolume.
Roselli, L; Paparella, F; Stanca, E; Basset, A
2015-06-01
Confocal laser scanner microscopy coupled with an image analysis system was used to directly determine the shape and calculate the biovolume of phytoplankton organisms by constructing 3D models of cells. The study was performed on Biceratium furca (Ehrenberg) Vanhoeffen, which is one of the most complex-shaped phytoplankton. Traditionally, biovolume is obtained from a standardized set of geometric models based on linear dimensions measured by light microscopy. However, especially in the case of complex-shaped cells, biovolume is affected by very large errors associated with the numerous manual measurements that this entails. We evaluate the accuracy of these traditional methods by comparing the results obtained using geometric models with direct biovolume measurement by image analysis. Our results show cell biovolume measurement based on decomposition into simple geometrical shapes can be highly inaccurate. Although we assume that the most accurate cell shape is obtained by 3D direct biovolume measurement, which is based on voxel counting, the intrinsic uncertainty of this method is explored and assessed. Finally, we implement a data-driven formula-based approach to the calculation of biovolume of this complex-shaped organism. On one hand, the model is obtained from 3D direct calculation. On the other hand, it is based on just two linear dimensions which can easily be measured by hand. This approach has already been used for investigating the complexities of morphology and for determining the 3D structure of cells. It could also represent a novel way to generalize scaling laws for biovolume calculation.
Temperature distributions in the laser-heated diamond anvil cell from 3-D numerical modeling
Rainey, E. S. G.; Kavner, A.; Hernlund, J. W.
2013-11-28
We present TempDAC, a 3-D numerical model for calculating the steady-state temperature distribution for continuous wave laser-heated experiments in the diamond anvil cell. TempDAC solves the steady heat conduction equation in three dimensions over the sample chamber, gasket, and diamond anvils and includes material-, temperature-, and direction-dependent thermal conductivity, while allowing for flexible sample geometries, laser beam intensity profile, and laser absorption properties. The model has been validated against an axisymmetric analytic solution for the temperature distribution within a laser-heated sample. Example calculations illustrate the importance of considering heat flow in three dimensions for the laser-heated diamond anvil cell. In particular, we show that a “flat top” input laser beam profile does not lead to a more uniform temperature distribution or flatter temperature gradients than a wide Gaussian laser beam.
Azcona, Juan Diego; Barbés, Benigno; Wang, Lilie; Burguete, Javier
2016-01-07
This paper presents a method to obtain the pencil-beam kernels that characterize a megavoltage photon beam generated in a flattening filter free (FFF) linear accelerator (linac) by deconvolution from experimental measurements at different depths. The formalism is applied to perform independent dose calculations in modulated fields. In our previous work a formalism was developed for ideal flat fluences exiting the linac's head. That framework could not deal with spatially varying energy fluences, so any deviation from the ideal flat fluence was treated as a perturbation. The present work addresses the necessity of implementing an exact analysis where any spatially varying fluence can be used such as those encountered in FFF beams. A major improvement introduced here is to handle the actual fluence in the deconvolution procedure. We studied the uncertainties associated to the kernel derivation with this method. Several Kodak EDR2 radiographic films were irradiated with a 10 MV FFF photon beam from two linacs from different vendors, at the depths of 5, 10, 15, and 20cm in polystyrene (RW3 water-equivalent phantom, PTW Freiburg, Germany). The irradiation field was a 50mm diameter circular field, collimated with a lead block. The 3D kernel for a FFF beam was obtained by deconvolution using the Hankel transform. A correction on the low dose part of the kernel was performed to reproduce accurately the experimental output factors. Error uncertainty in the kernel derivation procedure was estimated to be within 0.2%. Eighteen modulated fields used clinically in different treatment localizations were irradiated at four measurement depths (total of fifty-four film measurements). Comparison through the gamma-index to their corresponding calculated absolute dose distributions showed a number of passing points (3%, 3mm) mostly above 99%. This new procedure is more reliable and robust than the previous one. Its ability to perform accurate independent dose calculations was
NASA Astrophysics Data System (ADS)
Diego Azcona, Juan; Barbés, Benigno; Wang, Lilie; Burguete, Javier
2016-01-01
This paper presents a method to obtain the pencil-beam kernels that characterize a megavoltage photon beam generated in a flattening filter free (FFF) linear accelerator (linac) by deconvolution from experimental measurements at different depths. The formalism is applied to perform independent dose calculations in modulated fields. In our previous work a formalism was developed for ideal flat fluences exiting the linac’s head. That framework could not deal with spatially varying energy fluences, so any deviation from the ideal flat fluence was treated as a perturbation. The present work addresses the necessity of implementing an exact analysis where any spatially varying fluence can be used such as those encountered in FFF beams. A major improvement introduced here is to handle the actual fluence in the deconvolution procedure. We studied the uncertainties associated to the kernel derivation with this method. Several Kodak EDR2 radiographic films were irradiated with a 10 MV FFF photon beam from two linacs from different vendors, at the depths of 5, 10, 15, and 20cm in polystyrene (RW3 water-equivalent phantom, PTW Freiburg, Germany). The irradiation field was a 50mm diameter circular field, collimated with a lead block. The 3D kernel for a FFF beam was obtained by deconvolution using the Hankel transform. A correction on the low dose part of the kernel was performed to reproduce accurately the experimental output factors. Error uncertainty in the kernel derivation procedure was estimated to be within 0.2%. Eighteen modulated fields used clinically in different treatment localizations were irradiated at four measurement depths (total of fifty-four film measurements). Comparison through the gamma-index to their corresponding calculated absolute dose distributions showed a number of passing points (3%, 3mm) mostly above 99%. This new procedure is more reliable and robust than the previous one. Its ability to perform accurate independent dose calculations was
Perfetti, Christopher M; Rearden, Bradley T
2014-01-01
This work introduces a new approach for calculating sensitivity coefficients for generalized neutronic responses to nuclear data uncertainties using continuous-energy Monte Carlo methods. The approach presented in this paper, known as the GEAR-MC method, allows for the calculation of generalized sensitivity coefficients for multiple responses in a single Monte Carlo calculation with no nuclear data perturbations or knowledge of nuclear covariance data. The theory behind the GEAR-MC method is presented here, and proof of principle is demonstrated by using the GEAR-MC method to calculate sensitivity coefficients for responses in several 3D, continuous-energy Monte Carlo applications.
Magnetic Damping of g-Jitter Driven Flows: 3-D Calculations
NASA Technical Reports Server (NTRS)
Shang, D. Y.; Li, B. Q.; deGroh, H. C.
1997-01-01
A 3-D numerical model is developed to represent the oscillating natural convection induced in a cylindrical cavity filled with Ga-doped germanium with and without the presence of an external magnetic field. The model is developed based on the penalty-finite element solution of the equations describing the transport of momentum, heat and solutal element as well as the electromagnetic field distribution in the melt pool. Automatic time step control is applied to help speed up the calculations. Numerical simulations are conducted to study the convection and magnetic damping effects as a function of frequency, directions and amplitudes of g-jitter and also the direction and magnitudes of the applied magnetic fields. The results show that the g-jitter driven flow is time dependent and exhibits a complex recirculating convection pattern in three dimensions and that an applied magnetic field can be employed to suppress this deleterious convective flow and both magnitude and orientation of the applied field are important in magnetic damping of the g-jitter induced convective flows.
3D calculation of Tucson-Melbourne 3NF effect in triton binding energy
Hadizadeh, M. R.; Tomio, L.; Bayegan, S.
2010-08-04
As an application of the new realistic three-dimensional (3D) formalism reported recently for three-nucleon (3N) bound states, an attempt is made to study the effect of three-nucleon forces (3NFs) in triton binding energy in a non partial wave (PW) approach. The spin-isospin dependent 3N Faddeev integral equations with the inclusion of 3NFs, which are formulated as function of vector Jacobi momenta, specifically the magnitudes of the momenta and the angle between them, are solved with Bonn-B and Tucson-Melbourne NN and 3N forces in operator forms which can be incorporated in our 3D formalism. The comparison with numerical results in both, novel 3D and standard PW schemes, shows that non PW calculations avoid the very involved angular momentum algebra occurring for the permutations and transformations and it is more efficient and less cumbersome for considering the 3NF.
3D calculation of Tucson-Melbourne 3NF effect in triton binding energy
NASA Astrophysics Data System (ADS)
Hadizadeh, M. R.; Tomio, L.; Bayegan, S.
2010-08-01
As an application of the new realistic three-dimensional (3D) formalism reported recently for three-nucleon (3N) bound states, an attempt is made to study the effect of three-nucleon forces (3NFs) in triton binding energy in a non partial wave (PW) approach. The spin-isospin dependent 3N Faddeev integral equations with the inclusion of 3NFs, which are formulated as function of vector Jacobi momenta, specifically the magnitudes of the momenta and the angle between them, are solved with Bonn-B and Tucson-Melbourne NN and 3N forces in operator forms which can be incorporated in our 3D formalism. The comparison with numerical results in both, novel 3D and standard PW schemes, shows that non PW calculations avoid the very involved angular momentum algebra occurring for the permutations and transformations and it is more efficient and less cumbersome for considering the 3NF.
Calculation of strain images of a breast-mimicking phantom from 3D CT image data.
Kim, Jae G; Aowlad Hossain, A B M; Shin, Jong H; Lee, Soo Y
2012-09-01
Elastography is a medical imaging modality to visualize the elasticity of soft tissues. Ultrasound and MRI have been exclusively used for elastography of soft tissues since they can sensitize the tissues' minute displacements of an order of μm. It is known that ultrasound and MRI elastography show cancerous tissues with much higher contrast than conventional ultrasound and MRI. To evaluate possibility of combining elastography with x-ray imaging, we have calculated strain images of a breast-mimicking phantom from its 3D CT image data. We first simulated the x-ray elastography using a FEM model which incorporated both the elasticity and x-ray attenuation behaviors of breast tissues. After validating the x-ray elastography scheme by simulation, we made a breast-mimicking phantom that contained a hard inclusion against soft background. With a micro-CT, we took 3D images of the phantom twice, changing the compressing force to the phantom. From the two 3D phantom images taken with two different compression ratios, we calculated the displacement vector maps that represented the compression-induced pixel displacements. In calculating the displacement vectors, we tracked the movements of image feature patterns from the less-compressed-phantom images to the more-compressed-phantom images using the 3D image correlation technique. We obtained strain images of the phantom by differentiating the displacement vector maps. The FEM simulation has shown that x-ray strain imaging is possible by tracking image feature patterns in the 3D CT images of the breast-mimicking phantom. The experimental displacement and strain images of a breast-mimicking phantom, obtained from the 3D micro-CT images taken with 0%-3% compression ratios, show behaviors similar to the FEM simulation results. The contrast and noise performance of the strain images improves as the phantom compression ratio increases. We have experimentally shown that we can improve x-ray strain image quality by applying 3D
SALE-3D: a simplified ALE computer program for calculating three-dimensional fluid flow
Amsden, A.A.; Ruppel, H.M.
1981-11-01
This report presents a simplified numerical fluid-dynamics computing technique for calculating time-dependent flows in three dimensions. An implicit treatment of the pressure equation permits calculation of flows far subsonic without stringent constraints on the time step. In addition, the grid vertices may be moved with the fluid in Lagrangian fashion or held fixed in an Eulerian manner, or moved in some prescribed manner to give a continuous rezoning capability. This report describes the combination of Implicit Continuous-fluid Eulerian (ICE) and Arbitrary Lagrangian-Eulerian (ALE) to form the ICEd-ALE technique in the framework of the Simplified-ALE (SALE-3D) computer program, for which a general flow diagram and complete FORTRAN listing are included. Sample problems show how to modify the code for a variety of applications. SALE-3D is patterned as closely as possible on the previously reported two-dimensional SALE program.
Band like Electronic Structures in Square Hollow Quantum Dots by 3D-MHFKS Calculation
NASA Astrophysics Data System (ADS)
Takizawa, Tokihiro; Okada, Hoshihito; Matsuse, Takehiro
To find novel aspects of the electronic structures in quantum dots (QD) from a view point of spatial broken symmetry, 3-dimensional-mesh Hartree-Fock-Kohn-Sham (3D-MHFKS) calculations1 are applied to the interacting electron system of electron number N in a symmetry broken hollow QD. For the case of a square hollow quantum dot confined in square hard wall (HW) potential (SSHQD), the magnetic (B) field dependence of the obtained single particle energy levels and chemical potentials in B-N diagram are shown to have a band like electronic structures over the wide B-field range up to 20T. To clarify the origin of the band like electronic structures in SSHQD, 3D-MHFKS calculations are also applied for the mixed symmetry QD's with a circular hollow in square HW potential (SCHQD) and with a square hollow in circular HW potential (CSHQD).
NASA Astrophysics Data System (ADS)
Luchko, Tyler; Blinov, Nikolay; Limon, Garrett C.; Joyce, Kevin P.; Kovalenko, Andriy
2016-11-01
Implicit solvent methods for classical molecular modeling are frequently used to provide fast, physics-based hydration free energies of macromolecules. Less commonly considered is the transferability of these methods to other solvents. The Statistical Assessment of Modeling of Proteins and Ligands 5 (SAMPL5) distribution coefficient dataset and the accompanying explicit solvent partition coefficient reference calculations provide a direct test of solvent model transferability. Here we use the 3D reference interaction site model (3D-RISM) statistical-mechanical solvation theory, with a well tested water model and a new united atom cyclohexane model, to calculate partition coefficients for the SAMPL5 dataset. The cyclohexane model performed well in training and testing (R=0.98 for amino acid neutral side chain analogues) but only if a parameterized solvation free energy correction was used. In contrast, the same protocol, using single solute conformations, performed poorly on the SAMPL5 dataset, obtaining R=0.73 compared to the reference partition coefficients, likely due to the much larger solute sizes. Including solute conformational sampling through molecular dynamics coupled with 3D-RISM (MD/3D-RISM) improved agreement with the reference calculation to R=0.93. Since our initial calculations only considered partition coefficients and not distribution coefficients, solute sampling provided little benefit comparing against experiment, where ionized and tautomer states are more important. Applying a simple pK_{ {a}} correction improved agreement with experiment from R=0.54 to R=0.66, despite a small number of outliers. Better agreement is possible by accounting for tautomers and improving the ionization correction.
Luchko, Tyler; Blinov, Nikolay; Limon, Garrett C; Joyce, Kevin P; Kovalenko, Andriy
2016-11-01
Implicit solvent methods for classical molecular modeling are frequently used to provide fast, physics-based hydration free energies of macromolecules. Less commonly considered is the transferability of these methods to other solvents. The Statistical Assessment of Modeling of Proteins and Ligands 5 (SAMPL5) distribution coefficient dataset and the accompanying explicit solvent partition coefficient reference calculations provide a direct test of solvent model transferability. Here we use the 3D reference interaction site model (3D-RISM) statistical-mechanical solvation theory, with a well tested water model and a new united atom cyclohexane model, to calculate partition coefficients for the SAMPL5 dataset. The cyclohexane model performed well in training and testing ([Formula: see text] for amino acid neutral side chain analogues) but only if a parameterized solvation free energy correction was used. In contrast, the same protocol, using single solute conformations, performed poorly on the SAMPL5 dataset, obtaining [Formula: see text] compared to the reference partition coefficients, likely due to the much larger solute sizes. Including solute conformational sampling through molecular dynamics coupled with 3D-RISM (MD/3D-RISM) improved agreement with the reference calculation to [Formula: see text]. Since our initial calculations only considered partition coefficients and not distribution coefficients, solute sampling provided little benefit comparing against experiment, where ionized and tautomer states are more important. Applying a simple [Formula: see text] correction improved agreement with experiment from [Formula: see text] to [Formula: see text], despite a small number of outliers. Better agreement is possible by accounting for tautomers and improving the ionization correction.
Panthere V2: Multipurpose Simulation Software for 3D Dose Rate Calculations
NASA Astrophysics Data System (ADS)
Penessot, Gaël; Bavoil, Éléonore; Wertz, Laurent; Malouch, Fadhel; Visonneau, Thierry; Dubost, Julien
2017-09-01
PANTHERE is a multipurpose radiation protection software developed by EDF to calculate gamma dose rates in complex 3D environments. PANTHERE takes a key role in the EDF ALARA process, enabling to predict dose rates and to organize and optimize operations in high radiation environments. PANTHERE is also used for nuclear waste characterization, transport of nuclear materials, etc. It is used in most of the EDF engineering units and their design service providers and industrial partners.
Simulation of the impact of 3-D porosity distribution in metallic U-10Zr fuels
NASA Astrophysics Data System (ADS)
Yun, Di; Yacout, Abdellatif M.; Stan, Marius; Bauer, Theodore H.; Wright, Arthur E.
2014-05-01
Evolution of porosity generated in metallic U-Zr fuel irradiated in fast spectrum reactors leads to changes in fuel properties and impacts important phenomena such as heat transport and constituent redistribution. The porosity is generated as a result of the accumulation of fission gases and is affected by the possible bond sodium infiltration into the fuel. Typically, the impact of porosity development on properties, such as thermal conductivity, is accounted for through empirical correlations that are dependent on porosity and infiltrated sodium fractions. Currently available simulation tools make it possible to take into account fuel 3-D porosity distributions, potentially eliminating the need for such correlations. This development allows for a more realistic representation of the porosity evolution in metallic fuel and creates a framework for truly mechanistic fuel development models. In this work, COMSOL multi-physics simulation platform is used to model 3-D porosity distributions and simulate heat transport in metallic U-10Zr fuel. Available experimental data regarding microstructural evolution of fuel that was irradiated in EBR-II and associated phase stability information are used to guide the simulation. The impact of changes in porosity characteristics on material properties is estimated and the results are compared with calculated temperature distributions. The simulations demonstrate the developed capability and importance of accounting for detailed porosity distribution features for accurate fuel performance evaluation.
Schilling, Kurt; Janve, Vaibhav; Gao, Yurui; Stepniewska, Iwona; Landman, Bennett A; Anderson, Adam W
2016-01-01
The ability of diffusion MRI (dMRI) fiber tractography to non-invasively map three-dimensional (3D) anatomical networks in the human brain has made it a valuable tool in both clinical and research settings. However, there are many assumptions inherent to any tractography algorithm that can limit the accuracy of the reconstructed fiber tracts. Among them is the assumption that the diffusion-weighted images accurately reflect the underlying fiber orientation distribution (FOD) in the MRI voxel. Consequently, validating dMRI’s ability to assess the underlying fiber orientation in each voxel is critical for its use as a biomedical tool. Here, using post-mortem histology and confocal microscopy, we present a method to perform histological validation of orientation functions in 3D, which has previously been limited to two-dimensional analysis of tissue sections. We demonstrate the ability to extract the 3D FOD from confocal z-stacks, and quantify the agreement between the MRI estimates of orientation information obtained using constrained spherical deconvolution (CSD) and the true geometry of the fibers. We find an orientation error of approximately 6° in voxels containing nearly parallel fibers, and 10-11° in crossing fiber regions, and note that CSD was unable to resolve fibers crossing at angles below 60° in our dataset. This is the first time the 3D white matter orientation distribution is calculated from histology and compared to dMRI. Thus, this technique serves as a gold standard for dMRI validation studies - providing the ability to determine the extent to which the dMRI signal is consistent with the histological FOD, and to establish how well different dMRI models can predict the ground truth FOD. PMID:26804781
Method for measuring compliances and crack length by strain gauge and 3D finite element calculation
Riedle, J.; Wulf, J.; Schmauder, S.
1995-05-01
A method for determining compliances and crack lengths of round CT specimen geometries (RCT) by measuring the notch opening displacement (NOD) with strain gauges, combined with 3D finite element calculations to correlate the NOD to the loading point displacements, is presented. The method has been verified for tungsten and it is shown that measured and calculated compliances are in excellent agreement. A general equation is presented correlating compliances and NOD which allows to implicitly determine crack lengths by simply measuring the NOD of RCT specimens. 5 refs.
Efficient Sample Delay Calculation for 2-D and 3-D Ultrasound Imaging.
Ibrahim, Aya; Hager, Pascal A; Bartolini, Andrea; Angiolini, Federico; Arditi, Marcel; Thiran, Jean-Philippe; Benini, Luca; De Micheli, Giovanni
2017-08-01
Ultrasound imaging is a reference medical diagnostic technique, thanks to its blend of versatility, effectiveness, and moderate cost. The core computation of all ultrasound imaging methods is based on simple formulae, except for those required to calculate acoustic propagation delays with high precision and throughput. Unfortunately, advanced three-dimensional (3-D) systems require the calculation or storage of billions of such delay values per frame, which is a challenge. In 2-D systems, this requirement can be four orders of magnitude lower, but efficient computation is still crucial in view of low-power implementations that can be battery-operated, enabling usage in numerous additional scenarios. In this paper, we explore two smart designs of the delay generation function. To quantify their hardware cost, we implement them on FPGA and study their footprint and performance. We evaluate how these architectures scale to different ultrasound applications, from a low-power 2-D system to a next-generation 3-D machine. When using numerical approximations, we demonstrate the ability to generate delay values with sufficient throughput to support 10 000-channel 3-D imaging at up to 30 fps while using 63% of a Virtex 7 FPGA, requiring 24 MB of external memory accessed at about 32 GB/s bandwidth. Alternatively, with similar FPGA occupation, we show an exact calculation method that reaches 24 fps on 1225-channel 3-D imaging and does not require external memory at all. Both designs can be scaled to use a negligible amount of resources for 2-D imaging in low-power applications and for ultrafast 2-D imaging at hundreds of frames per second.
a Distributed Online 3D-LIDAR Mapping System
NASA Astrophysics Data System (ADS)
Schmiemann, J.; Harms, H.; Schattenberg, J.; Becker, M.; Batzdorfer, S.; Frerichs, L.
2017-08-01
In this paper we are presenting work done within the joint development project ANKommEn. It deals with the development of a highly automated robotic system for fast data acquisition in civil disaster scenarios. One of the main requirements is a versatile system, hence the concept embraces a machine cluster consisting of multiple fundamentally different robotic platforms. To cover a large variety of potential deployment scenarios, neither the absolute amount of participants, nor the precise individual layout of each platform shall be restricted within the conceptual design. Thus leading to a variety of special requirements, like onboard and online data processing capabilities for each individual participant and efficient data exchange structures, allowing reliable random data exchange between individual robots. We are demonstrating the functionality and performance by means of a distributed mapping system evaluated with real world data in a challenging urban and rural indoor/outdoor scenarios.
Tensor decomposition in electronic structure calculations on 3D Cartesian grids
Khoromskij, B.N. Khoromskaia, V.; Chinnamsetty, S.R.; Flad, H.-J.
2009-09-01
In this paper, we investigate a novel approach based on the combination of Tucker-type and canonical tensor decomposition techniques for the efficient numerical approximation of functions and operators in electronic structure calculations. In particular, we study applicability of tensor approximations for the numerical solution of Hartree-Fock and Kohn-Sham equations on 3D Cartesian grids. We show that the orthogonal Tucker-type tensor approximation of electron density and Hartree potential of simple molecules leads to low tensor rank representations. This enables an efficient tensor-product convolution scheme for the computation of the Hartree potential using a collocation-type approximation via piecewise constant basis functions on a uniform nxnxn grid. Combined with the Richardson extrapolation, our approach exhibits O(h{sup 3}) convergence in the grid-size h=O(n{sup -1}). Moreover, this requires O(3rn+r{sup 3}) storage, where r denotes the Tucker rank of the electron density with r=O(logn), almost uniformly in n. For example, calculations of the Coulomb matrix and the Hartree-Fock energy for the CH{sub 4} molecule, with a pseudopotential on the C atom, achieved accuracies of the order of 10{sup -6} hartree with a grid-size n of several hundreds. Since the tensor-product convolution in 3D is performed via 1D convolution transforms, our scheme markedly outperforms the 3D-FFT in both the computing time and storage requirements.
Holographic multi-focus 3D two-photon polymerization with real-time calculated holograms.
Vizsnyiczai, Gaszton; Kelemen, Lóránd; Ormos, Pál
2014-10-06
Two-photon polymerization enables the fabrication of micron sized structures with submicron resolution. Spatial light modulators (SLM) have already been used to create multiple polymerizing foci in the photoresist by holographic beam shaping, thus enabling the parallel fabrication of multiple microstructures. Here we demonstrate the parallel two-photon polymerization of single 3D microstructures by multiple holographically translated foci. Multiple foci were created by phase holograms, which were calculated real-time on an NVIDIA CUDA GPU, and displayed on an electronically addressed SLM. A 3D demonstrational structure was designed that is built up from a nested set of dodecahedron frames of decreasing size. Each individual microstructure was fabricated with the parallel and coordinated motion of 5 holographic foci. The reproducibility and the high uniformity of features of the microstructures were verified by scanning electron microscopy.
Progress on accelerated calculation of 3D MHD equilibrium with the PIES code
NASA Astrophysics Data System (ADS)
Raburn, Daniel; Reiman, Allan; Monticello, Donald
2016-10-01
Continuing progress has been made in accelerating the 3D MHD equilibrium code, PIES, using an external numerical wrapper. The PIES code (Princeton Iterative Equilibrium Solver) is capable of calculating 3D MHD equilibria with islands. The numerical wrapper has been demonstrated to greatly improve the rate of convergence in numerous cases corresponding to equilibria in the TFTR device where magnetic islands are present; the numerical wrapper makes use of a Jacobian-free Newton-Krylov solver along with adaptive preconditioning and a sophisticated subspace-restricted Levenberg backtracking algorithm. The wrapper has recently been improved by automation which combines the preexisting backtracking algorithm with insights gained from the stability of the Picard algorithm traditionally used with PIES. Improved progress logging and stopping criteria have also been incorporated in to the numerical wrapper.
The solar silicon abundance based on 3D non-LTE calculations
NASA Astrophysics Data System (ADS)
Amarsi, A. M.; Asplund, M.
2017-01-01
We present 3D non-local thermodynamic equilibrium (non-LTE) radiative transfer calculations for silicon in the solar photosphere, using an extensive model atom that includes recent, realistic neutral hydrogen collisional cross-sections. We find that photon losses in the Si I lines give rise to slightly negative non-LTE abundance corrections of the order of -0.01 dex. We infer a 3D non-LTE-based solar silicon abundance of lg ɛ_{Si{⊙}}=7.51 dex. With silicon commonly chosen to be the anchor between the photospheric and meteoritic abundances, we find that the meteoritic abundance scale remains unchanged compared with the Asplund et al. and Lodders et al. results.
SU-E-T-535: Preliminary 2D and 3D Gamma Calculation Comparison Using PRESAGE
Lafratta, R; Yang, J; Sahoo, N; Tucker, S; Followill, D; Ibbott, G
2014-06-01
Purpose: To compare gamma calculations from 2D and 3D dosimetry measurements for phantom quality assurance. Methods: An IROC Houston (RPC) head and neck phantom was irradiated with a 9 beam IMRT plan using two inserts: a TLD and film insert and a PRESAGE insert. Both inserts were irradiated 3 times. The film and PRESAGE doses were scaled to the TLD dose and 2D gamma calculations were made in the axial and sagittal planes bisecting the primary target. 3D gamma measurements were taken within the PRESAGE dosimeter volume. Gamma constraints of 3%/3mm distance to agreement (DTA), 5%/3mm DTA and 7%/4mm DTA were used in the study. The 3 irradiations for each insert were averaged together for comparison. Results: Film measurements for the 2D gamma showed 85% pixels passing at 3%/3mm in both planes. The 5%/3 mm constraint had 93% and 90% passing in the two planes. The 7%/4mm restraint resulted in 99% passing in both planes. The PRESAGE 2D gamma passed 66% and 61% of pixels in the both planes at 3%/3mm. At 5%/3mm 86% and 82% passed. For 7%/4mm, 94% of pixels passed in both planes. The 3D gamma resulted in a pass rate of 90% at 3%/3mm, 95% at 5%/3mm, and 99% at 7%/4mm. Conclusion: 2D gamma pass rates using film showed a higher pass rate than PRESAGE using the same criteria in the same planes. This may be due to poor 3D registration with the treatment plan compared to the 2D film registration system. The 3D gamma results had a higher pass rate (> 90% pass rate) possibly because it sampled many more pixels in noncritical volumes thus diluting the percent of pixels passing. 3D restraints should be more restrictive to be comparable to 2D results. Funding from NIH grant 5R01CA100835.
3-D Distribution of Retained Colloids in Unsaturated Porous Media
NASA Astrophysics Data System (ADS)
Morales, V. L.; Perez-Reche, F. J.; Holzner, M.; Kinzelbach, W. K.; Otten, W.
2013-12-01
It is well accepted that colloid transport processes in porous media differ substantially between water saturated and unsaturated conditions. Differences are frequently ascribed to colloid immobilization by association with interfaces with the gas, as well as to restrictions of the liquid medium through which colloids are transported. Such factors depend on interfacial conditions provided by the water saturation of the porous medium. Yet, the current understanding of the importance of colloid retention at gas interfaces is based on observations of single pores or two-dimensional pore network representations, leaving open the question of their statistical significance when all pores in the medium are considered. In order to address this question, column experiments were performed using a model porous medium of glass beads through which colloidal silver particles were transported for conditions of varying water content. X-ray microtomography was subsequently employed as a non-destructive imaging technique to obtain pore-scale information of the entire column regarding: i) the presence and distribution of the four main locations where colloids can become retained (interfaces with the liquid-solid, gas-liquid and gas-solid, and the bulk liquid), ii) deposition profiles of colloids along the column classified by the available retention location, iii) morphological characteristics of the deposited colloidal aggregates, and iv) channel widths of 3-dimensional pore-water network representations. The results presented provide, for the first time, a direct statistical evaluation on the significance of colloid retention by attachment to the liquid-solid, gas-liquid, gas-solid interfaces, and by straining in the bulk liquid. Additionally, an effective-pore structure characteristic is proposed to improve predictions of mass removal by straining under various water saturations. A) Unsaturated conditions. B) Saturated conditions. Left: Tomograph slice illustrating with false
Adamson, Justus; Newton, Joseph; Yang, Yun; Steffey, Beverly; Cai, Jing; Adamovics, John; Oldham, Mark; Chino, Junzo; Craciunescu, Oana
2012-07-01
To determine the geometric and dose attenuation characteristics of a new commercially available CT-compatible LDR tandem and ovoid (T&O) applicator using Monte Carlo calculation and 3D dosimetry. For geometric characterization, we quantified physical dimensions and investigated a systematic difference found to exist between nominal ovoid angle and the angle at which the afterloading buckets fall within the ovoid. For dosimetric characterization, we determined source attenuation through asymmetric gold shielding in the buckets using Monte Carlo simulations and 3D dosimetry. Monte Carlo code MCNP5 was used to simulate 1.5 × 10(9) photon histories from a (137)Cs source placed in the bucket to achieve statistical uncertainty of 1% at a 6 cm distance. For 3D dosimetry, the distribution about an unshielded source was first measured to evaluate the system for (137)Cs, after which the distribution was measured about sources placed in each bucket. Cylindrical PRESAGE(®) dosimeters (9.5 cm diameter, 9.2 cm height) with a central channel bored for source placement were supplied by Heuris Inc. The dosimeters were scanned with the Duke Large field of view Optical CT-Scanner before and after delivering a nominal dose at 1 cm of 5-8 Gy. During irradiation the dosimeter was placed in a water phantom to provide backscatter. Optical CT scan time lasted 15 min during which 720 projections were acquired at 0.5° increments, and a 3D distribution was reconstructed with a (0.05 cm)(3) isotropic voxel size. The distributions about the buckets were used to calculate a 3D distribution of transmission rate through the bucket, which was applied to a clinical CT-based T&O implant plan. The systematic difference in bucket angle relative to the nominal ovoid angle (105°) was 3.1°-4.7°. A systematic difference in bucket angle of 1°, 5°, and 10° caused a 1% ± 0.1%, 1.7% ± 0.4%, and 2.6% ± 0.7% increase in rectal dose, respectively, with smaller effect to dose to Point A, bladder
Adamson, Justus; Newton, Joseph; Yang Yun; Steffey, Beverly; Cai, Jing; Adamovics, John; Oldham, Mark; Chino, Junzo; Craciunescu, Oana
2012-07-15
Purpose: To determine the geometric and dose attenuation characteristics of a new commercially available CT-compatible LDR tandem and ovoid (T and O) applicator using Monte Carlo calculation and 3D dosimetry. Methods: For geometric characterization, we quantified physical dimensions and investigated a systematic difference found to exist between nominal ovoid angle and the angle at which the afterloading buckets fall within the ovoid. For dosimetric characterization, we determined source attenuation through asymmetric gold shielding in the buckets using Monte Carlo simulations and 3D dosimetry. Monte Carlo code MCNP5 was used to simulate 1.5 Multiplication-Sign 10{sup 9} photon histories from a {sup 137}Cs source placed in the bucket to achieve statistical uncertainty of 1% at a 6 cm distance. For 3D dosimetry, the distribution about an unshielded source was first measured to evaluate the system for {sup 137}Cs, after which the distribution was measured about sources placed in each bucket. Cylindrical PRESAGE{sup Registered-Sign} dosimeters (9.5 cm diameter, 9.2 cm height) with a central channel bored for source placement were supplied by Heuris Inc. The dosimeters were scanned with the Duke Large field of view Optical CT-Scanner before and after delivering a nominal dose at 1 cm of 5-8 Gy. During irradiation the dosimeter was placed in a water phantom to provide backscatter. Optical CT scan time lasted 15 min during which 720 projections were acquired at 0.5 Degree-Sign increments, and a 3D distribution was reconstructed with a (0.05 cm){sup 3} isotropic voxel size. The distributions about the buckets were used to calculate a 3D distribution of transmission rate through the bucket, which was applied to a clinical CT-based T and O implant plan. Results: The systematic difference in bucket angle relative to the nominal ovoid angle (105 Degree-Sign ) was 3.1 Degree-Sign -4.7 Degree-Sign . A systematic difference in bucket angle of 1 Degree-Sign , 5 Degree-Sign , and
Elucidating the scapulo-humeral rhythm calculation: 3D joint contribution method.
Robert-Lachaine, Xavier; Marion, Patrick; Godbout, Véronique; Bleau, Jacinte; Begon, Mickael
2015-01-01
The scapulo-humeral rhythm quantifies shoulder joint coordination during arm elevation. The common method calculates a ratio of gleno-humeral (GH) elevation to scapulo-thoracic upward rotation angles. However the other rotations also contribute to arm elevation. The objective is to propose a 3D dynamic scapulo-humeral rhythm calculation method including all rotations of the shoulder joints and compare with the common method. Twenty-nine skin markers were placed on the trunk and dominant arm of 14 healthy males to measure shoulder kinematics. Two-way repeated measures ANOVAs were applied to compare the two methods of calculation of joint contributions and scapulo-humeral rhythm during arm elevation. Significant main effects (p < 0.05) were observed between methods in joint contribution angles and scapulo-humeral rhythms. A systematic overestimation of the GH contribution was observed when only using the GH elevation angle because the scapula is moved outside a vertical plane. Hence, the proposed 3D method to calculate the scapulo-humeral rhythm allows an improved functional shoulder evaluation.
Influence of intrinsic and extrinsic forces on 3D stress distribution using CUDA programming
NASA Astrophysics Data System (ADS)
Räss, Ludovic; Omlin, Samuel; Podladchikov, Yuri
2013-04-01
In order to have a better understanding of the influence of buoyancy (intrinsic) and boundary (extrinsic) forces in a nonlinear rheology due to a power law fluid, some basics needs to be explored through 3D numerical calculation. As first approach, the already studied Stokes setup of a rising sphere will be used to calibrate the 3D model. Far field horizontal tectonic stress is applied to the sphere, which generates a vertical acceleration, buoyancy driven. This simple and known setup allows some benchmarking performed through systematic runs. The relative importance of intrinsic and extrinsic forces producing the wide variety of rates and styles of deformation, including absence of deformation and generating 3D stress patterns, will be determined. Relation between vertical motion and power law exponent will also be explored. The goal of these investigations will be to run models having topography and density structure from geophysical imaging as input, and 3D stress field as output. The stress distribution in Swiss Alps and Plateau and its implication for risk analysis is one of the perspective for this research. In fact, proximity of the stress to the failure is fundamental for risk assessment. Sensitivity of this to the accurate topography representation can then be evaluated. The developed 3D numerical codes, tuned for mid-sized cluster, need to be optimized, especially while running good resolution in full 3D. Therefor, two largely used computing platforms, MATLAB and FORTRAN 90 are explored. Starting with an easy adaptable and as short as possible MATLAB code, which is then upgraded in order to reach higher performance in simulation times and resolution. A significant speedup using the rising NVIDIA CUDA technology and resources is also possible. Programming in C-CUDA, creating some synchronization feature, and comparing the results with previous runs, helps us to investigate the new speedup possibilities allowed through GPU parallel computing. These codes
NASA Astrophysics Data System (ADS)
Bobrowski, Piotr; Faryna, Marek; Pędzich, Zbigniew
2017-06-01
A set of yttria-stabilized zirconia samples sintered at increasing temperatures was investigated using two-dimensional (2D) and three-dimensional (3D) electron backscatter diffraction (EBSD) techniques to calculate grain size distributions and grain boundary densities. The obtained results were compared to the results of stereological calculations and revealed that mean intercept length, a commonly used stereological parameter, is ca. 20% lower than an average grain diameter derived from 2D and 3D EBSD data. Moreover, the results based on 2D and 3D EBSD analyses were similar to each other in grain boundary density, while the values obtained from the stereological approach were noticeably lower.
Wang, Xi-fen; Zhou, Huai-chun
2005-01-01
The control of 3-D temperature distribution in a utility boiler furnace is essential for the safe, economic and clean operation of pc-fired furnace with multi-burner system. The development of the visualization of 3-D temperature distributions in pc-fired furnaces makes it possible for a new combustion control strategy directly with the furnace temperature as its goal to improve the control quality for the combustion processes. Studied in this paper is such a new strategy that the whole furnace is divided into several parts in the vertical direction, and the average temperature and its bias from the center in every cross section can be extracted from the visualization results of the 3-D temperature distributions. In the simulation stage, a computational fluid dynamics (CFD) code served to calculate the 3-D temperature distributions in a furnace, then a linear model was set up to relate the features of the temperature distributions with the input of the combustion processes, such as the flow rates of fuel and air fed into the furnaces through all the burners. The adaptive genetic algorithm was adopted to find the optimal combination of the whole input parameters which ensure to form an optimal 3-D temperature field in the furnace desired for the operation of boiler. Simulation results showed that the strategy could soon find the factors making the temperature distribution apart from the optimal state and give correct adjusting suggestions.
Calculating Pressure-Driven Current Near Magnetic Islands for 3D MHD Equilibria
NASA Astrophysics Data System (ADS)
Radhakrishnan, Dhanush; Reiman, Allan
2016-10-01
In general, 3D MHD equilibria in toroidal plasmas do not result in nested pressure surfaces. Instead, islands and chaotic regions appear in the equilibrium. Near small magnetic islands, the pressure varies within the flux surfaces, which has a significant effect on the pressure-driven current, introducing singularities. Previously, the MHD equilibrium current near a magnetic island was calculated, including the effect of ``stellarator symmetry,'' wherein the singular components of the pressure-driven current vanish [A. H. Reiman, Phys. Plasmas 23, 072502 (2016)]. Here we first solve for pressure in a cylindrical plasma from the heat diffusion equation, after adding a helical perturbation. We then numerically calculate the corresponding Pfirsch-Schluter current. At the small island limit, we compare the pressure-driven current with the previously calculated solution, and far from the island, we recover the solution for nested flux surfaces. Lastly, we compute the current for a toroidal plasma for symmetric and non-symmetric geometries.
3D neutronic calculations: CAD-MCNP methodology applied to vessel activation in KOYO-F
NASA Astrophysics Data System (ADS)
Herreras, Y.; Lafuente, A.; Sordo, F.; Cabellos, O.; Perlado, J. M.
2008-05-01
This paper presents a methodology for 3D neutronic calculations suitable for complex and extensive geometries. The geometry of the system design is first fully modelled with a CAD program, and subsequently processed through a MCNP-CAD interface in order to generate an MCNP geometry file. Neutronic irradiation results are finally achieved running the MCNPX program, where the geometry input card used is directly the MCNP-CAD interface output. This methodology enables accurate neutronic calculations for complex geometries characterised by high detail levels. This procedure will be applied to the Fast Ignition Fusion Reactor KOYO-F to determine first neutron fluxes calculations along the blanket as well as the material activation in the reduced martensitic 9Cr-1Mo steel vessel.
Analysis of the 3D distribution of stacked self-assembled quantum dots by electron tomography
2012-01-01
The 3D distribution of self-assembled stacked quantum dots (QDs) is a key parameter to obtain the highest performance in a variety of optoelectronic devices. In this work, we have measured this distribution in 3D using a combined procedure of needle-shaped specimen preparation and electron tomography. We show that conventional 2D measurements of the distribution of QDs are not reliable, and only 3D analysis allows an accurate correlation between the growth design and the structural characteristics. PMID:23249477
Mochan, W Luis; Ortiz, Guillermo P; Mendoza, Bernardo S
2010-10-11
We present a very efficient recursive method to calculate the effective optical response of metamaterials made up of arbitrarily shaped inclusions arranged in periodic 3D arrays. We apply it to dielectric particles embedded in a metal matrix with a lattice constant much smaller than the wavelength of the incident field, so that we may neglect retardation and factor the geometrical properties from the properties of the materials. If the conducting phase is continuous the low frequency behavior is metallic, and if the conducting paths are thin, the high frequency behavior is dielectric. Thus, extraordinary-transparency bands may develop at intermediate frequencies, whose properties may be tuned by geometrical manipulation.
A system for 3D representation of burns and calculation of burnt skin area.
Prieto, María Felicidad; Acha, Begoña; Gómez-Cía, Tomás; Fondón, Irene; Serrano, Carmen
2011-11-01
In this paper a computer-based system for burnt surface area estimation (BAI), is presented. First, a 3D model of a patient, adapted to age, weight, gender and constitution is created. On this 3D model, physicians represent both burns as well as burn depth allowing the burnt surface area to be automatically calculated by the system. Each patient models as well as photographs and burn area estimation can be stored. Therefore, these data can be included in the patient's clinical records for further review. Validation of this system was performed. In a first experiment, artificial known sized paper patches were attached to different parts of the body in 37 volunteers. A panel of 5 experts diagnosed the extent of the patches using the Rule of Nines. Besides, our system estimated the area of the "artificial burn". In order to validate the null hypothesis, Student's t-test was applied to collected data. In addition, intraclass correlation coefficient (ICC) was calculated and a value of 0.9918 was obtained, demonstrating that the reliability of the program in calculating the area is of 99%. In a second experiment, the burnt skin areas of 80 patients were calculated using BAI system and the Rule of Nines. A comparison between these two measuring methods was performed via t-Student test and ICC. The hypothesis of null difference between both measures is only true for deep dermal burns and the ICC is significantly different, indicating that the area estimation calculated by applying classical techniques can result in a wrong diagnose of the burnt surface. Copyright © 2011 Elsevier Ltd and ISBI. All rights reserved.
Development of 3D pseudo pin-by-pin calculation methodology in ANC
Zhang, B.; Mayhue, L.; Huria, H.; Ivanov, B.
2012-07-01
Advanced cores and fuel assembly designs have been developed to improve operational flexibility, economic performance and further enhance safety features of nuclear power plants. The simulation of these new designs, along with strong heterogeneous fuel loading, have brought new challenges to the reactor physics methodologies currently employed in the industrial codes for core analyses. Control rod insertion during normal operation is one operational feature in the AP1000{sup R} plant of Westinghouse next generation Pressurized Water Reactor (PWR) design. This design improves its operational flexibility and efficiency but significantly challenges the conventional reactor physics methods, especially in pin power calculations. The mixture loading of fuel assemblies with significant neutron spectrums causes a strong interaction between different fuel assembly types that is not fully captured with the current core design codes. To overcome the weaknesses of the conventional methods, Westinghouse has developed a state-of-the-art 3D Pin-by-Pin Calculation Methodology (P3C) and successfully implemented in the Westinghouse core design code ANC. The new methodology has been qualified and licensed for pin power prediction. The 3D P3C methodology along with its application and validation will be discussed in the paper. (authors)
First-principles calculations of the interaction between hydrogen and 3d alloying atom in nickel
NASA Astrophysics Data System (ADS)
Liu, Wenguan; Qian, Yuan; Zhang, Dongxun; Liu, Wei; Han, Han
2015-10-01
Knowledge of the behavior of hydrogen (H) in Ni-based alloy is essential for the prediction of Tritium behavior in Molten Salt Reactor. First-principles calculations were performed to investigate the interaction between H and 3d transition metal (TM) alloying atom in Ni-based alloy. H prefers the octahedral interstitial site to the tetrahedral interstitial site energetically. Most of the 3d TM elements (except Zn) attract H. The attraction to H in the Ni-TM-H system can be mainly attributed to the differences in electronegativity. With the large electronegativity, H and Ni gain electrons from the other TM elements, resulting in the enhanced Ni-H bonds which are the source of the attraction to H in the Ni-TM-H system. The obviously covalent-like Cr-H and Co-H bindings are also beneficial to the attraction to H. On the other hand, the repulsion to H in the Ni-Zn-H system is due to the stable electronic configuration of Zn. We mainly utilize the results calculated in 32-atom supercell which corresponds to the case of a relatively high concentration of hydrogen. Our results are in good agreement with the experimental ones.
[A 3D FEM model for calculation of electromagnetic fields in transmagnetic stimulation].
Seilwinder, J; Kammer, T; Andrä, W; Bellemann, M E
2002-01-01
We developed a realistic finite elements method (FEM) model of the brain for the calculation of electromagnetic fields in transcranial magnetic stimulation (TMS). A focal butterfly stimulation coil was X-rayed, parameterized, and modeled. The magnetic field components of the TMS coil were calculated and compared for validation to pointwise measurements of the magnetic fields with a Hall sensor. We found a mean deviation of 7.4% at an axial distance of 20 mm to the coil. A 3D brain model with the biological tissues of white and gray matter, bone, and cerebrospinal fluid was developed. At a current sweep of 1000 A in 120 microseconds, the maximum induced current density in gray matter was 177 mA/m2 and the strongest electric field gradient covered an area of 40 mm x 53 mm.
TE/TM alternating direction scheme for wake field calculation in 3D
NASA Astrophysics Data System (ADS)
Zagorodnov, Igor; Weiland, Thomas
2006-03-01
In the future, accelerators with very short bunches will be used. It demands developing new numerical approaches for long-time calculation of electromagnetic fields in the vicinity of relativistic bunches. The conventional FDTD scheme, used in MAFIA, ABCI and other wake and PIC codes, suffers from numerical grid dispersion and staircase approximation problem. As an effective cure of the dispersion problem, a numerical scheme without dispersion in longitudinal direction can be used as it was shown by Novokhatski et al. [Transition dynamics of the wake fields of ultrashort bunches, TESLA Report 2000-03, DESY, 2000] and Zagorodnov et al. [J. Comput. Phys. 191 (2003) 525]. In this paper, a new economical conservative scheme for short-range wake field calculation in 3D is presented. As numerical examples show, the new scheme is much more accurate on long-time scale than the conventional FDTD approach.
3D dose and TCP distribution for radionuclide therapy in nuclear medicine
NASA Astrophysics Data System (ADS)
Valente, M.; Malano, F.; Pérez, P.
2010-08-01
A common feature to any radiant therapy is that lesion and health tissue dosimetry provides relevant information for treatment optimization along with dose-efficacy and dose-complication correlation studies. Nowadays, different radionuclide therapies are commonly available, assessing both systemic and loco-regional approach and using different alfa-, beta-and gamma-emitting isotopes and binding molecules. It is well established, that specific dosimetric approaches become necessary according to each therapy modality. Sometimes, observed activity distribution can be satisfactory represented by simple geometrical models. However, Monte Carlo techniques are capable of better approaches, therefore becoming sometimes the only way to get dosimetric data since the patient-specific situation can not be adequately represented by conventional dosimetry techniques. Therefore, due to strong limitations of traditional and standard methods, this work concentrates on the development of a dedicated and novel calculation system in order to assess the dose distribution within the irradiated patient. However, physical dose may not be enough information in order to establish real deterministic biological/metabolic effects; therefore complementary radiobiological models have been suitably introduced with the aim of performing realistic 3D dose as well as corresponding Tumor Control Probability distribution calculation.
Measurement of carbon ion microdosimetric distributions with ultrathin 3D silicon diodes
NASA Astrophysics Data System (ADS)
Gómez, F.; Fleta, C.; Esteban, S.; Quirion, D.; Pellegrini, G.; Lozano, M.; Prezado, Y.; Dos Santos, M.; Guardiola, C.; Montarou, G.; Prieto-Pena, J.; Pardo-Montero, Juan
2016-06-01
The commissioning of an ion beam for hadrontherapy requires the evaluation of the biologically weighted effective dose that results from the microdosimetric properties of the therapy beam. The spectra of the energy imparted at cellular and sub-cellular scales are fundamental to the determination of the biological effect of the beam. These magnitudes are related to the microdosimetric distributions of the ion beam at different points along the beam path. This work is dedicated to the measurement of microdosimetric spectra at several depths in the central axis of a 12C beam with an energy of 94.98 AMeV using a novel 3D ultrathin silicon diode detector. Data is compared with Monte Carlo calculations providing an excellent agreement (deviations are less than 2% for the most probable lineal energy value) up to the Bragg peak. The results show the feasibility to determine with high precision the lineal energy transfer spectrum of a hadrontherapy beam with these silicon devices.
Measurement of carbon ion microdosimetric distributions with ultrathin 3D silicon diodes.
Gómez, F; Fleta, C; Esteban, S; Quirion, D; Pellegrini, G; Lozano, M; Prezado, Y; Dos Santos, M; Guardiola, C; Montarou, G; Prieto-Pena, J; Pardo-Montero, Juan
2016-06-07
The commissioning of an ion beam for hadrontherapy requires the evaluation of the biologically weighted effective dose that results from the microdosimetric properties of the therapy beam. The spectra of the energy imparted at cellular and sub-cellular scales are fundamental to the determination of the biological effect of the beam. These magnitudes are related to the microdosimetric distributions of the ion beam at different points along the beam path. This work is dedicated to the measurement of microdosimetric spectra at several depths in the central axis of a (12)C beam with an energy of 94.98 AMeV using a novel 3D ultrathin silicon diode detector. Data is compared with Monte Carlo calculations providing an excellent agreement (deviations are less than 2% for the most probable lineal energy value) up to the Bragg peak. The results show the feasibility to determine with high precision the lineal energy transfer spectrum of a hadrontherapy beam with these silicon devices.
Ma, M; Rouabhi, O; Flynn, R; Xia, J; Bayouth, J
2014-06-01
Purpose: To evaluate the dosimetric difference between 3D and 4Dweighted dose calculation using patient specific respiratory trace and deformable image registration for stereotactic body radiation therapy in lung tumors. Methods: Two dose calculation techniques, 3D and 4D-weighed dose calculation, were used for dosimetric comparison for 9 lung cancer patients. The magnitude of the tumor motion varied from 3 mm to 23 mm. Breath-hold exhale CT was used for 3D dose calculation with ITV generated from the motion observed from 4D-CT. For 4D-weighted calculation, dose of each binned CT image from the ten breathing amplitudes was first recomputed using the same planning parameters as those used in the 3D calculation. The dose distribution of each binned CT was mapped to the breath-hold CT using deformable image registration. The 4D-weighted dose was computed by summing the deformed doses with the temporal probabilities calculated from their corresponding respiratory traces. Dosimetric evaluation criteria includes lung V20, mean lung dose, and mean tumor dose. Results: Comparing with 3D calculation, lung V20, mean lung dose, and mean tumor dose using 4D-weighted dose calculation were changed by −0.67% ± 2.13%, −4.11% ± 6.94% (−0.36 Gy ± 0.87 Gy), −1.16% ± 1.36%(−0.73 Gy ± 0.85 Gy) accordingly. Conclusion: This work demonstrates that conventional 3D dose calculation method may overestimate the lung V20, MLD, and MTD. The absolute difference between 3D and 4D-weighted dose calculation in lung tumor may not be clinically significant. This research is supported by Siemens Medical Solutions USA, Inc and Iowa Center for Research By Undergraduates.
Riazi, Z; Afarideh, H; Sadighi-Bonabi, R
2011-09-01
Based on the determination of protons fluence at the phantom's surface, a 3D dose distribution is calculated inside a water phantom using a fast method. The dose contribution of secondary particles, originating from inelastic nuclear interactions, is also taken into account. This is achieved by assuming that 60% of the energy transferred to secondary particles is locally absorbed. Secondary radiation delivers approximately 16.8% of the total dose in the plateau region of the Bragg curve for monoenergetic protons of energy 190 MeV. The physical dose beyond the Bragg peak is obtained for a proton beam of 190 MeV using a Geant4 simulation. It is found that the dose beyond the Bragg peak is <0.02% of the maximum dose and is mainly delivered by protons produced via reactions of the secondary neutrons. The relative dose profile is also calculated by simulation of the proposed beam line in Geant4 code. The dose profile produced by our method agrees, within 2%, with the results predicted by the Fermi Eyges distribution function and the results of the Geant4 simulation. It is expected that the fast numerical approach proposed herein may be utilised in 3D deterministic treatment planning programs, to model proton propagation in order to analyse the effect of modifying the beam line.
An approach to 3D magnetic field calculation using numerical and differential algebra methods
Caspi, S.; Helm, M.; Laslett, L.J.; Brady, V.O.
1992-07-17
Motivated by the need for new means for specification and determination of 3D fields that are produced by electromagnetic lens elements in the region interior to coil windings and seeking to obtain techniques that will be convenient for accurate conductor placement and dynamical study of particle motion, we have conveniently gene the representation of a 2D magnetic field to 3D. We have shown that the 3 dimensioal magnetic field components of a multipole magnet in the curl-fire divergence-fire region near the axis r=0 can be derived from one dimensional functions A{sub n}(z) and their derivatives (part 1). In the region interior to coil windings of accelerator magnets the three spatial components of magnet fields can be expressed in terms of harmonic components'' proportional to functions sin (n{theta}) or cos (n{theta}) of the azimuthal angle. The r,z dependence of any such component can then be expressed in terms of powers of r times functions A{sub n}(z) and their derivatives. For twodimensional configurations B{sub z} of course is identically zero, the derivatives of A{sub n}(z) vanish, and the harmonic components of the transverse field then acquire a simple proportionality B{sub r,n} {proportional to} r{sup n-1} sin (n{theta}),B{sub {theta},n} {proportional to} r{sup n-1} cos (n{theta}), whereas in a 3-D configuration the more complex nature of the field gives rise to additional so-called psuedomultipole'' components as judged by additional powers of r required in the development of the field. Computation of the 3-D magnetic field arising at a sequence of field points, as a direct result of a specified current configuration or coil geometry, can be calculated explicitly through use of the Biot-Savart law and from such data the coefficients can then be derived for a general development of the type indicated above. We indicate, discuss, and illustrate two means by which this development may be performed.
3D nozzle flow simulations including state-to-state kinetics calculation
NASA Astrophysics Data System (ADS)
Cutrone, L.; Tuttafesta, M.; Capitelli, M.; Schettino, A.; Pascazio, G.; Colonna, G.
2014-12-01
In supersonic and hypersonic flows, thermal and chemical non-equilibrium is one of the fundamental aspects that must be taken into account for the accurate characterization of the plasma. In this paper, we present an optimized methodology to approach plasma numerical simulation by state-to-state kinetics calculations in a fully 3D Navier-Stokes CFD solver. Numerical simulations of an expanding flow are presented aimed at comparing the behavior of state-to-state chemical kinetics models with respect to the macroscopic thermochemical non-equilibrium models that are usually used in the numerical computation of high temperature hypersonic flows. The comparison is focused both on the differences in the numerical results and on the computational effort associated with each approach.
3D detection of obstacle distribution in walking guide system for the blind
NASA Astrophysics Data System (ADS)
Yoon, Myoung-Jong; Yu, Kee-Ho
2007-12-01
In this paper, the concept of a walking guide system with tactile display is introduced, and experiments of 3-D obstacle detection and tactile perception are carried out and analyzed. The algorithm of 3-D obstacle detection and the method of mapping the generated obstacle map and the tactile display device for the walking guide system are proposed. The experiment of the 3-D detection for the obstacle position using ultrasonic sensors is performed and estimated. Some design guidelines for a tactile display device that can display obstacle distribution is discussed.
3D beam shape estimation based on distributed coaxial cable interferometric sensor
NASA Astrophysics Data System (ADS)
Cheng, Baokai; Zhu, Wenge; Liu, Jie; Yuan, Lei; Xiao, Hai
2017-03-01
We present a coaxial cable interferometer based distributed sensing system for 3D beam shape estimation. By making a series of reflectors on a coaxial cable, multiple Fabry–Perot cavities are created on it. Two cables are mounted on the beam at proper locations, and a vector network analyzer (VNA) is connected to them to obtain the complex reflection signal, which is used to calculate the strain distribution of the beam in horizontal and vertical planes. With 6 GHz swept bandwidth on the VNA, the spatial resolution for distributed strain measurement is 0.1 m, and the sensitivity is 3.768 MHz mε ‑1 at the interferogram dip near 3.3 GHz. Using displacement-strain transformation, the shape of the beam is reconstructed. With only two modified cables and a VNA, this system is easy to implement and manage. Comparing to optical fiber based sensor systems, the coaxial cable sensors have the advantage of large strain and robustness, making this system suitable for structure health monitoring applications.
A novel time dependent gamma evaluation function for dynamic 2D and 3D dose distributions.
Podesta, Mark; Persoon, Lucas C G G; Verhaegen, Frank
2014-10-21
Modern external beam radiotherapy requires detailed verification and quality assurance so that confidence can be placed on both the delivery of a single treatment fraction and on the consistency of delivery throughout the treatment course. To verify dose distributions, a comparison between prediction and measurement must be made. Comparisons between two dose distributions are commonly performed using a Gamma evaluation which is a calculation of two quantities on a pixel by pixel basis; the dose difference, and the distance to agreement. By providing acceptance criteria (e.g. 3%, 3 mm), the function will find the most appropriate match within its two degrees of freedom. For complex dynamic treatments such as IMRT or VMAT it is important to verify the dose delivery in a time dependent manner and so a gamma evaluation that includes a degree of freedom in the time domain via a third parameter, time to agreement, is presented here. A C++ (mex) based gamma function was created that could be run on either CPU and GPU computing platforms that would allow a degree of freedom in the time domain. Simple test cases were created in both 2D and 3D comprising of simple geometrical shapes with well-defined boundaries varying over time. Changes of varying magnitude in either space or time were introduced and repeated gamma analyses were performed varying the criteria. A clinical VMAT case was also included, artificial air bubbles of varying size were introduced to a patient geometry, along with shifts of varying magnitude in treatment time. For all test cases where errors in distance, dose or time were introduced, the time dependent gamma evaluation could accurately highlight the errors.The time dependent gamma function presented here allows time to be included as a degree of freedom in gamma evaluations. The function allows for 2D and 3D data sets which are varying over time to be compared using appropriate criteria without penalising minor offsets of subsequent radiation fields
A novel time dependent gamma evaluation function for dynamic 2D and 3D dose distributions
NASA Astrophysics Data System (ADS)
Podesta, Mark; CGG Persoon, Lucas; Verhaegen, Frank
2014-10-01
Modern external beam radiotherapy requires detailed verification and quality assurance so that confidence can be placed on both the delivery of a single treatment fraction and on the consistency of delivery throughout the treatment course. To verify dose distributions, a comparison between prediction and measurement must be made. Comparisons between two dose distributions are commonly performed using a Gamma evaluation which is a calculation of two quantities on a pixel by pixel basis; the dose difference, and the distance to agreement. By providing acceptance criteria (e.g. 3%, 3 mm), the function will find the most appropriate match within its two degrees of freedom. For complex dynamic treatments such as IMRT or VMAT it is important to verify the dose delivery in a time dependent manner and so a gamma evaluation that includes a degree of freedom in the time domain via a third parameter, time to agreement, is presented here. A C++ (mex) based gamma function was created that could be run on either CPU and GPU computing platforms that would allow a degree of freedom in the time domain. Simple test cases were created in both 2D and 3D comprising of simple geometrical shapes with well-defined boundaries varying over time. Changes of varying magnitude in either space or time were introduced and repeated gamma analyses were performed varying the criteria. A clinical VMAT case was also included, artificial air bubbles of varying size were introduced to a patient geometry, along with shifts of varying magnitude in treatment time. For all test cases where errors in distance, dose or time were introduced, the time dependent gamma evaluation could accurately highlight the errors. The time dependent gamma function presented here allows time to be included as a degree of freedom in gamma evaluations. The function allows for 2D and 3D data sets which are varying over time to be compared using appropriate criteria without penalising minor offsets of subsequent radiation
PFLOW: A 3-D Numerical Modeling Tool for Calculating Fluid-Pressure Diffusion from Coulomb Strain
NASA Astrophysics Data System (ADS)
Wolf, L. W.; Lee, M.; Meir, A.; Dyer, G.; Ma, K.; Chan, C.
2009-12-01
A new 3D time-dependent pore-pressure diffusion model PFLOW is developed to investigate the response of pore fluids to the crustal deformation generated by strong earthquakes in heterogeneous geologic media. Given crustal strain generated by changes in Coulomb stress, this MATLAB-based code uses Skempton's coefficient to calculate resulting changes fluid pressure. Pore-pressure diffusion can be tracked over time in a user-defined model space with user-prescribed Neumann or Dirchilet boundary conditions and with spatially variable values of permeability. PFLOW employs linear or quadratic finite elements for spatial discretization and first order or second order, explicit or implicit finite difference discretization in time. PFLOW is easily interfaced with output from deformation modeling programs such as Coulomb (Toda et al., 2007) or 3D-DEF (Gomberg and Ellis, 1994). The code is useful for investigating to first-order the evolution of pore pressure changes induced by changes in Coulomb stress and their possible relation to water-level changes in wells or changes in stream discharge. It can also be used for student research and classroom instruction. As an example application, we calculate the coseismic pore pressure changes and diffusion induced by volumetric strain associated with the 1999 Chi-Chi earthquake (Mw = 7.6) in Taiwan. The Chi-Chi earthquake provides an unique opportunity to investigate the spatial and time-dependent poroelastic response of near-field rocks and sediments because there exist extensive observational data of water-level changes and crustal deformation. The integrated model allows us to explore whether changes in Coulomb stress can adequately explain hydrologic anomalies observed in areas such as Taiwan’s western foothills and the Choshui River alluvial plain. To calculate coseismic strain, we use the carefully calibrated finite fault-rupture model of Ma et al. (2005) and the deformation modeling code Coulomb 3.1 (Toda et al., 2007
Non-Ideal ELM Stability and Non-Axisymmetric Field Penetration Calculations with M3D-C1
NASA Astrophysics Data System (ADS)
Ferraro, N. M.; Chu, M. S.; Snyder, P. B.; Jardin, S. C.; Luo, X.
2009-11-01
Numerical studies of ELM stability and non-axisymmetric field penetration in diverted DIII-D and NSTX equilibria are presented, with resistive and finite Larmor radius effects included. These results are obtained with the nonlinear two-fluid code M3D-C1, which has recently been extended to allow linear non-axisymmetric calculations. Benchmarks of M3D-C1 with ideal codes ELITE and GATO show good agreement for the linear stability of peeling-ballooning modes in the ideal limit. New calculations of the resistive stability of ideally stable DIII-D equilibria are presented. M3D-C1 has also been used to calculate the linear response to non-axisymmetric external fields; these calculations are benchmarked with Surfmn and MARS-F. New numerical methods implemented in M3D-C1 are presented, including the treatment of boundary conditions with C^1 elements in a non-rectangular mesh.
Calculation of the nuclear material inventory in a sealed vault by 3D radiation mapping
Adsley, Ian; Klepikov, Alexander; Tur, Yevgeniy; Wells, David
2013-07-01
The paper relates to the determination of the amount of nuclear material contained in a closed, concrete lined vault at the Aktau fast breeder reactor in Kazakhstan. This material had been disposed into the vault after examination in an experimental hot cell directly above the vault. In order to comply with IAEA Safeguards requirements it was necessary to determine the total quantities of nuclear materials - enriched uranium and plutonium - that were held with Kazakhstan. Although it was possible to determine the inventory of all of the accessible nuclear material - the quantity remaining in the vault was unknown. As part of the Global Threat Reduction Programme the UK Government funded a project to determine the inventory of these nuclear materials in this vault. This involved drilling three penetrations through the concrete lined roof of the vault; this enabled the placement of lights and a camera into the vault through two penetrations; while the third penetration enabled a lightweight manipulator arm to be introduced into the vault. This was used to provide a detailed 3D mapping of the dose rate within the vault and it also enabled the collection of samples for radionuclide analysis. The deconvolution of the 3D dose rate profile within the vault enabled the determination of the gamma emitting source distribution on the floor and walls of the vault. The samples were analysed to determine the fingerprint of those radionuclides producing the gamma dose - namely {sup 137}Cs and {sup 60}Co - to the nuclear materials. The combination of the dose rate source terms on the surfaces of the vault and the fingerprint then enabled the quantities of nuclear materials to be determined. The project was a major success and enabled the Kazakhstan Government to comply with IAEA Safeguards requirements. It also enabled the UK DECC Ministry to develop a technology of national (and international) use. Finally the technology was well received by IAEA Safeguards as an acceptable
PARC3D calculations of the F/A-18A HARV inlet vortex generators
NASA Technical Reports Server (NTRS)
Podleski, Steve D.
1995-01-01
NASA Lewis Research Center is currently engaged in a research effort as a team member of the High Alpha Technology Program within the NASA agency. This program uses a specially-equipped F/A-18A aircraft called the High Alpha Research Vehicle (HARV), in an effort to improve the maneuverability of high performance military aircraft at low-subsonic-speed, high-angle-of-attack conditions. The overall objective of the NASA Lewis effort is to develop inlet analysis technology towards efficient airflow delivery to the engine during these maneuvers. One portion of this inlet analysis technology uses computational fluid dynamics to predict installed inlet performance. Most of the F/A-18A HARV geometry, which includes the ramp/splitter plate, side diverter and slot, inlet lip and upper diverter, and deflected leading-edge flap has been modeled. The empennage and rear fuselage have not. A pair of vortex generators located on the bottom wall of the inlet were not modeled initially. These vortex generators were installed to alleviate any flow separation that may be induced by the wheel well protrusion into the inlet wall. Calculations completed with the PARC3D code showed that the pressure recovery has been underpredicted and the flow distortion over-predicted. To improve the correlation of PARC3D predictions with flight and wind tunnel tests, the vortex generators were included in the grid geometry and the results are presented in this report. The grid totals 27 blocks or 1.3 million grid points for the half model, which includes the vortex generator grid blocks. Two flight cases were calculated, a high speed case with a Mach number of 0.8 and angle of attack of 3.4; and a low speed case with a Mach number of 0.43 and angle of attack of 32.2. The vortex generators have a significant effect on the inlet boundary layers at high speed, low angle of attack; and have no effect at low speed, high angle of attack.
NASA Astrophysics Data System (ADS)
Balanin, A. L.; Boyarinov, V. F.; Glushkov, E. S.; Zimin, A. A.; Kompaniets, G. V.; Nevinitsa, V. A.; Moroz, N. P.; Fomichenko, P. A.; Timoshinov, A. V.; Volkov, Yu. N.
2016-12-01
The application of experimental information on measured axial distributions of fission reaction rates for development of 3D numerical models of the ASTRA critical facility taking into account azimuthal asymmetry of the assembly simulating a HTGR with annular core is substantiated. Owing to the presence of the bottom reflector and the absence of the top reflector, the application of 2D models based on experimentally determined buckling is impossible for calculation of critical assemblies of the ASTRA facility; therefore, an alternative approach based on the application of the extrapolated assembly height is proposed. This approach is exemplified by the numerical analysis of experiments on measurement of efficiency of control rods mockups and protection system (CPS).
Balanin, A. L.; Boyarinov, V. F.; Glushkov, E. S.; Zimin, A. A.; Kompaniets, G. V.; Nevinitsa, V. A. Moroz, N. P.; Fomichenko, P. A.; Timoshinov, A. V.; Volkov, Yu. N.
2016-12-15
The application of experimental information on measured axial distributions of fission reaction rates for development of 3D numerical models of the ASTRA critical facility taking into account azimuthal asymmetry of the assembly simulating a HTGR with annular core is substantiated. Owing to the presence of the bottom reflector and the absence of the top reflector, the application of 2D models based on experimentally determined buckling is impossible for calculation of critical assemblies of the ASTRA facility; therefore, an alternative approach based on the application of the extrapolated assembly height is proposed. This approach is exemplified by the numerical analysis of experiments on measurement of efficiency of control rods mockups and protection system (CPS).
3-D calculation of gap closure in the DARHT-2 diode
NASA Astrophysics Data System (ADS)
Hughes, Thomas; Davis, Harold
2003-10-01
The DARHT-2 facility at Los Alamos National Laboratory uses a long-pulse (2 microsecond), high current (2 kA) induction accelerator to generate a high-energy (18 MV) electron beam. A thermionic cathode surrounded by a Pierce electrode is used to supply the electron current. Because of the long pulse-length, a point plasma formed due to high field-stress on the Pierce electrode may have time to expand and develop into a high-current source in parallel with the thermionic source. This parasitic current may damage the injector by deflecting the main beam into the wall. If its current is large enough, it could directly damage the anode electrode. A fail-safe mechanism has been proposed [Ref. 1] where a parasitic current monitor can trigger a diverter switch, causing the current from the Marx generator to bypass the diode. We will present results of 3-D diode calculations using a realistic model of the expanding plasma to compute the parasitic current. This allows us to determine the effect on the main beam, and to predict the behavior of the fail-safe circuit. [1] S. Eylon, LBNL.
The PIES2012 Code for Calculating 3D Equilibria with Islands and Stochastic Regions
NASA Astrophysics Data System (ADS)
Monticello, Donald; Reiman, Allan; Raburn, Daniel
2013-10-01
We have made major modifications to the PIES 3D equilibrium code to produce a new version, PIES2012. The new version uses an adaptive radial grid for calculating equilibrium currents. A subset of the flux surfaces conform closely to island separatrices, providing an accurate treatment of the effects driving the neoclassical tearing mode. There is now a set of grid surfaces that conform to the flux surfaces in the interiors of the islands, allowing the proper treatment of the current profiles in the islands, which play an important role in tearing phenomena. We have verified that we can introduce appropriate current profiles in the islands to suppress their growth, allowing us to simulate situations where islands are allowed to grow at some rational surfaces but not others. Placement of grid surfaces between islands is guided by the locations of high order fixed points, allowing us to avoid spectral polution and providing a more robust, and smoother convergence of the code. The code now has an option for turning on a vertical magnetic field to fix the position of the magnetic axis, which models the horizontal feedback positioning of a tokamak plasma. The code has a new option for using a Jacobian-Free Newton Krylov scheme for convergence. The code now also contains a model that properly handles stochastic regions with nonzero pressure gradients. Work supported by DOE contract DE-AC02-09CH11466.
NASA Astrophysics Data System (ADS)
Maurer, Thomas; Brück, Yasemine; Hinz, Christoph; Gerke, Horst H.
2015-04-01
Structural heterogeneity, namely the spatial distribution of soils and sediments (represented by mineral particles), characterizes catchment hydrological behavior. In natural catchments, local geology and the specific geomorphic processes determine the characteristics and spatial distribution of structures. In constructed catchments, structural features are determined primarily by the construction processes and the geological origin of the parent material. Objectives are scenarios of 3D catchment structures in form of complete 3D description of soil hydraulic properties generated from the knowledge of the formation processes. The constructed hydrological catchment 'Hühnerwasser' (Lower Lusatia, Brandenburg, Germany) was used for the calibration and validation of model results due to its well-known conditions. For the modelling of structural features, a structure generator was used to model i) quasi-deterministic sediment distributions using input data from a geological model of the parent material excavation site; ii) sediment distributions that are conditioned to measurement data from soil sampling; and iii) stochastic component sediment distributions. All three approaches allow a randomization within definable limits. Furthermore, the spoil cone / spoil ridge orientation, internal layering, surface compaction and internal spoil cone compaction were modified. These generated structural models were incorporated in a gridded 3D volume model constructed with the GOCAD software. For selected scenarios, the impact of structure variation was assessed by hydrological modelling with HYDRUS 2D/3D software. For that purpose, 3D distributions of soil hydraulic properties were estimated based on generated sediment properties using adapted pedotransfer functions. Results from the hydrological model were compared them to measured discharges from the catchment. The impact of structural feature variation on flow behaviour was analysed by comparing different simulation scenarios
SU-E-T-192: Commissioning of a Commercial 3D Dose Calculation Program
Langen, K; Guerrero, M; Xu, H; Zhou, J; Zhang, B; Chen, S; Killefer, M
2015-06-15
Purpose: To commission a commercial software package (CSP) that is used as secondary dose calculation check. The CSP uses an independent golden data beam model. However, some parameters can be modified to generate a customer specific model. Plan comparisons and point dose measurements were performed to test if and to what extent the beam model needed adjustment to optimize results. Methods: Beam parameter configurations were compared between the CSP and both TPS. Twelve phantom test plans ranging from simple to complex were generated in two treatment planning systems (TPS). Tests included small field, off axis, EDW, IMRT and VMAT plans. For each plan a point dose was measured to establish ground truth. Lastly, patient plans were compared for both TPS systems and the CSP. Results: Beam parameters agreed within 2%. The output factors for small fields were changed for the 15 MV beam by 2 and 1.5 % for the 1 cm and 2 cm field sizes, respectively. For the 6 MV beam output factors were adjusted by 3−0.8% for field sizes ranging from 1 to 5 cm. The MLC dynamic leaf gap was adjusted by 1.5 mm for 18 MV beam. Differences between the CSP and the TPS were noted in the built-up region. These differences affected the gamma pass rate in the surface region, however this effect is reduced with increasing number of beam angles and does not affect point dose calculations at depth. All IMRT and VMAT plans agreed with the CSP using a gamma pass rate of 95% (3%, 3mm). Conclusion: The CSP is used to verify point doses for all 3D plans generated in our clinic for the last 6 months. No point dose mismatches were encountered since the CSP was implemented. Next, the CSP will be adapted for secondary checks of all IMRT plans. KL had a beta tester agreement with Mobius Medical for an in-kind equipment and software loan.
Calculation of grain boundary normals directly from 3D microstructure images
Lieberman, E. J.; Rollett, A. D.; Lebensohn, R. A.; ...
2015-03-11
The determination of grain boundary normals is an integral part of the characterization of grain boundaries in polycrystalline materials. These normal vectors are difficult to quantify due to the discretized nature of available microstructure characterization techniques. The most common method to determine grain boundary normals is by generating a surface mesh from an image of the microstructure, but this process can be slow, and is subject to smoothing issues. A new technique is proposed, utilizing first order Cartesian moments of binary indicator functions, to determine grain boundary normals directly from a voxelized microstructure image. In order to validate the accuracymore » of this technique, the surface normals obtained by the proposed method are compared to those generated by a surface meshing algorithm. Specifically, the local divergence between the surface normals obtained by different variants of the proposed technique and those generated from a surface mesh of a synthetic microstructure constructed using a marching cubes algorithm followed by Laplacian smoothing is quantified. Next, surface normals obtained with the proposed method from a measured 3D microstructure image of a Ni polycrystal are used to generate grain boundary character distributions (GBCD) for Σ3 and Σ9 boundaries, and compared to the GBCD generated using a surface mesh obtained from the same image. Finally, the results show that the proposed technique is an efficient and accurate method to determine voxelized fields of grain boundary normals.« less
Calculation of grain boundary normals directly from 3D microstructure images
Lieberman, E. J.; Rollett, A. D.; Lebensohn, R. A.; Kober, E. M.
2015-03-11
The determination of grain boundary normals is an integral part of the characterization of grain boundaries in polycrystalline materials. These normal vectors are difficult to quantify due to the discretized nature of available microstructure characterization techniques. The most common method to determine grain boundary normals is by generating a surface mesh from an image of the microstructure, but this process can be slow, and is subject to smoothing issues. A new technique is proposed, utilizing first order Cartesian moments of binary indicator functions, to determine grain boundary normals directly from a voxelized microstructure image. In order to validate the accuracy of this technique, the surface normals obtained by the proposed method are compared to those generated by a surface meshing algorithm. Specifically, the local divergence between the surface normals obtained by different variants of the proposed technique and those generated from a surface mesh of a synthetic microstructure constructed using a marching cubes algorithm followed by Laplacian smoothing is quantified. Next, surface normals obtained with the proposed method from a measured 3D microstructure image of a Ni polycrystal are used to generate grain boundary character distributions (GBCD) for Σ3 and Σ9 boundaries, and compared to the GBCD generated using a surface mesh obtained from the same image. Finally, the results show that the proposed technique is an efficient and accurate method to determine voxelized fields of grain boundary normals.
NASA Astrophysics Data System (ADS)
Wang, Haijun; Xu, Feiyun; Zhao, Jun'ai; Jia, Minping; Hu, Jianzhong; Huang, Peng
2013-11-01
Nonnegative Tucker3 decomposition(NTD) has attracted lots of attentions for its good performance in 3D data array analysis. However, further research is still necessary to solve the problems of overfitting and slow convergence under the anharmonic vibration circumstance occurred in the field of mechanical fault diagnosis. To decompose a large-scale tensor and extract available bispectrum feature, a method of conjugating Choi-Williams kernel function with Gauss-Newton Cartesian product based on nonnegative Tucker3 decomposition(NTD_EDF) is investigated. The complexity of the proposed method is reduced from o( n N lg n) in 3D spaces to o( R 1 R 2 nlg n) in 1D vectors due to its low rank form of the Tucker-product convolution. Meanwhile, a simultaneously updating algorithm is given to overcome the overfitting, slow convergence and low efficiency existing in the conventional one-by-one updating algorithm. Furthermore, the technique of spectral phase analysis for quadratic coupling estimation is used to explain the feature spectrum extracted from the gearbox fault data by the proposed method in detail. The simulated and experimental results show that the sparser and more inerratic feature distribution of basis images can be obtained with core tensor by the NTD_EDF method compared with the one by the other methods in bispectrum feature extraction, and a legible fault expression can also be performed by power spectral density(PSD) function. Besides, the deviations of successive relative error(DSRE) of NTD_EDF achieves 81.66 dB against 15.17 dB by beta-divergences based on NTD(NTD_Beta) and the time-cost of NTD_EDF is only 129.3 s, which is far less than 1 747.9 s by hierarchical alternative least square based on NTD (NTD_HALS). The NTD_EDF method proposed not only avoids the data overfitting and improves the computation efficiency but also can be used to extract more inerratic and sparser bispectrum features of the gearbox fault.
Xiao, Kai; Chen, Danny Z; Hu, X Sharon; Zhou, Bo
2012-12-01
The three-dimensional digital differential analyzer (3D-DDA) algorithm is a widely used ray traversal method, which is also at the core of many convolution∕superposition (C∕S) dose calculation approaches. However, porting existing C∕S dose calculation methods onto graphics processing unit (GPU) has brought challenges to retaining the efficiency of this algorithm. In particular, straightforward implementation of the original 3D-DDA algorithm inflicts a lot of branch divergence which conflicts with the GPU programming model and leads to suboptimal performance. In this paper, an efficient GPU implementation of the 3D-DDA algorithm is proposed, which effectively reduces such branch divergence and improves performance of the C∕S dose calculation programs running on GPU. The main idea of the proposed method is to convert a number of conditional statements in the original 3D-DDA algorithm into a set of simple operations (e.g., arithmetic, comparison, and logic) which are better supported by the GPU architecture. To verify and demonstrate the performance improvement, this ray traversal method was integrated into a GPU-based collapsed cone convolution∕superposition (CCCS) dose calculation program. The proposed method has been tested using a water phantom and various clinical cases on an NVIDIA GTX570 GPU. The CCCS dose calculation program based on the efficient 3D-DDA ray traversal implementation runs 1.42 ∼ 2.67× faster than the one based on the original 3D-DDA implementation, without losing any accuracy. The results show that the proposed method can effectively reduce branch divergence in the original 3D-DDA ray traversal algorithm and improve the performance of the CCCS program running on GPU. Considering the wide utilization of the 3D-DDA algorithm, various applications can benefit from this implementation method.
da Silva, Carlos Henrique Tomich de Paula; Taft, Carlton Anthony
2017-10-01
The knowledge of the bioactive conformation for an active hit is relevant because of the easier interpretation and the general quality of the recognition models of protein and ligand. With the aim of investigating potential bioactive conformations without previous structural knowledge of the molecular target, we present herewith a 'protocol' that could be used which includes generation of low-energy conformations, calculations of tridimensional descriptors and investigation of structural similarity via principal component analysis. The protocol was used in the search for potential bioactive conformations. An initial selection of targets was made from a set of protein-ligand complexes with structure deposited in the Protein Data Bank, which was systematically filtered by lead-like rules, resulting in 45 ligands of 8 important therapeutic targets. After extensive optimization of the protocol and parameters of both OMEGA and Pentacle softwares, the best results were obtained for series of compounds such as the beta-trypsin and urokinase inhibitors, which are more structurally related among each other, inside the respective therapeutic class. Future improvements of the protocol, including a suitable choice and combination of robust 3D descriptors, could yield more reliable and less restrictive results, with general and diverse applications in drug design, in particular for improving the 3D-QSAR methodologies as well as virtual screening experiments for a more reliable selection of new lead compounds for different molecular targets.
RayXpert V1: 3D software for the gamma dose rate calculation by Monte Carlo
NASA Astrophysics Data System (ADS)
Peyrard, P. F.; Pourrouquet, P.; Dossat, C.; Thomas, J. C.; Chatry, N.; Lavielle, D.; Chatry, C.
2014-06-01
RayXpert has been developed to ease the access to the power and accuracy of the 3D Monte Carlo method in the field of gamma dose rate estimate. Optimization methods have been implemented to address dose calculation behind thick 3D structures. At the same time, the engineering interface makes all the preprocessing tasks (modeling, material settings,…) faster using predefined tables and push button features.
3D Hydrodynamical Calculations on the Fragmentation of Pancakes and Galaxy Formation
NASA Astrophysics Data System (ADS)
Umemura, Masayuki
1992-05-01
The fragmentation of pancakes is numerically investigated by 3D smoothed particle hydrodynamics combined with N-body scheme, where the thermal processes by the cooling and heating are explicitly included and the self-gravity is calculated by the direct summation for all particle pairs. We consider baryon-dominated and hot dark matter-dominated pancakes. We find that the fragmentation is triggered in a central cooled dense layer of a pancake, and it obeys a two-step scenario: first the pancake exhibits some filamentary structures after collapse, and then they are torn to numerous fragments, eventually forming chain-like structures. The galaxy formation efficiency in pancake fragmentation is considerably small as fGF ~ exp [-2(M_pan/10(14}M_sun)({1/5)) ]. This is suggestive when compared with the recent observations on X-ray clusters. It is also found that the typical sizes of fragments are proportional to the pancake mass, M_pan. The mass of fragment is determined as M_b ~ 0.3-2times 10(12) M_sun (M_pan/10(15) M_sun) in baryonic component. Moreover the rotation curve of each fragment is asymptotically flat in the outer envelope. Other characteristic quantities as the total mass to baryon mass ratios, the line-of-sight relative peculiar velocity dispersion of fragments, the neutral hydrogen column density of each fragment at the high-redshift epoch, and the intergalactic gas heating and X-ray luminosity are also presented. The fragmentation processes are strongly dependent upon small-scale fluctuations. Unless there is any small-scale seed fluctuations, the pancakes cannot be fragmented. Therefore, a pure neutrino-dominated universe where small-scale fluctuations are thoroughly erased may be unsuccessful in galaxy formation. We require just a small amount of fluctuations of smaller scales than a neutrino collisionless damping scale for the formation of galaxies in the fragmentation scenario.
3D Neutronic Analysis in MHD Calculations at ARIES-ST Fusion Reactors Systems
NASA Astrophysics Data System (ADS)
Hançerliogulları, Aybaba; Cini, Mesut
2013-10-01
In this study, we developed new models for liquid wall (FW) state at ARIES-ST fusion reactor systems. ARIES-ST is a 1,000 MWe fusion reactor system based on a low aspect ratio ST plasma. In this article, we analyzed the characteristic properties of magnetohydrodynamics (MHD) and heat transfer conditions by using Monte-Carlo simulation methods (ARIES Team et al. in Fusion Eng Des 49-50:689-695, 2000; Tillack et al. in Fusion Eng Des 65:215-261, 2003) . In fusion applications, liquid metals are traditionally considered to be the best working fluids. The working liquid must be a lithium-containing medium in order to provide adequate tritium that the plasma is self-sustained and that the fusion is a renewable energy source. As for Flibe free surface flows, the MHD effects caused by interaction with the mean flow is negligible, while a fairly uniform flow of thick can be maintained throughout the reactor based on 3-D MHD calculations. In this study, neutronic parameters, that is to say, energy multiplication factor radiation, heat flux and fissile fuel breeding were researched for fusion reactor with various thorium and uranium molten salts. Sufficient tritium amount is needed for the reactor to work itself. In the tritium breeding ratio (TBR) >1.05 ARIES-ST fusion model TBR is >1.1 so that tritium self-sufficiency is maintained for DT fusion systems (Starke et al. in Fusion Energ Des 84:1794-1798, 2009; Najmabadi et al. in Fusion Energ Des 80:3-23, 2006).
Effects of inflow distortion profiles on fan tone noise calculated using a 3-D theory
NASA Technical Reports Server (NTRS)
Kobayashi, H.; Groeneweg, J. F.
1979-01-01
Calculations of the fan tone acoustic power and modal structure generated by complex distortions in axial inflow velocity are presented. The model used treats the motor as a rotating three-dimensional cascade and calculates the acoustic field from the distortion-produced dipole distribution on the blades including noncompact source effects. Radial and circumferential distortion shapes are synthesized from Fourier-Bessel components representing individual distortion modes. The relation between individual distortion modes and the generated acoustic modes is examined for particular distortion cases. Comparisons between theoretical and experimental results for distortions produced by wakes from upstream radial rods show that the analysis is a good predictor of acoustic power dependence on disturbance strength.
Effects of inflow distortion profiles on fan tone noise calculated using a 3-D theory
NASA Technical Reports Server (NTRS)
Kobayshi, H.; Groeneweg, J. F.
1979-01-01
Calculations of the fan tone acoustic power and modal structure generated by complex distortions in axial inflow velocity are presented. The model used treats the rotor as a rotating three-dimensional cascade and calculates the acoustic field from the distortion-produced dipole distribution on the blades including noncompact source effects. Radial and circumferential distortion shapes are synthesized from Fourier-Bessel components representing individual distortion modes. The relation between individual distortion modes and the generated acoustic modes is examined for particular distortion cases. Comparisons between theoretical and experimental results for distortions produced by wakes from upstream radial rods show that the analysis is a good predictor of acoustic power dependence on disturbance strength.
Assessment of Altered 3D Blood Characteristics in Aortic Disease by Velocity Distribution Analysis
Garcia, Julio; Barker, Alex J; van Ooij, Pim; Schnell, Susanne; Puthumana, Jyothy; Bonow, Robert O; Collins, Jeremy D; Carr, James C; Markl, Michael
2014-01-01
Purpose To test the feasibility of velocity distribution analysis for identifying altered 3D flow characteristics in patients with aortic disease based on 4D flow MRI volumetric analysis. Methods Forty patients with aortic (Ao) dilation (mid ascending aortic diameter MAA=40±7 mm, age=56±17 yr, 11 females) underwent cardiovascular MRI. Four groups were retrospectively defined: mild Ao dilation (n=10, MAA<35 mm); moderate Ao dilation (n=10, 35
Progressive Shape-Distribution-Encoder for Learning 3D Shape Representation.
Xie, Jin; Zhu, Fan; Dai, Guoxian; Shao, Ling; Fang, Yi
2017-03-01
Since there are complex geometric variations with 3D shapes, extracting efficient 3D shape features is one of the most challenging tasks in shape matching and retrieval. In this paper, we propose a deep shape descriptor by learning shape distributions at different diffusion time via a progressive shape-distribution-encoder (PSDE). First, we develop a shape distribution representation with the kernel density estimator to characterize the intrinsic geometry structures of 3D shapes. Then, we propose to learn a deep shape feature through an unsupervised PSDE. Specially, the unsupervised PSDE aims at modeling the complex non-linear transform of the estimated shape distributions between consecutive diffusion time. In order to characterize the intrinsic structures of 3D shapes more efficiently, we stack multiple PSDEs to form a network structure. Finally, we concatenate all neurons in the middle hidden layers of the unsupervised PSDE network to form an unsupervised shape descriptor for retrieval. Furthermore, by imposing an additional constraint on the outputs of all hidden layers, we propose a supervised PSDE to form a supervised shape descriptor. For each hidden layer, the similarity between a pair of outputs from the same class is as large as possible and the similarity between a pair of outputs from different classes is as small as possible. The proposed method is evaluated on three benchmark 3D shape data sets with large geometric variations, i.e., McGill, SHREC'10 ShapeGoogle, and SHREC'14 Human data sets, and the experimental results demonstrate the superiority of the proposed method to the existing approaches.
Han, Jeong-Hwan; Oda, Takuji
2017-04-12
Steels are easily corroded in a liquid lead-bismuth eutectic (LBE) because their components, such as Fe, Cr and Ni, exhibit a high solubility in the liquid LBE. To understand the reason for such a high solubility of these 3d transition metals, we have performed first-principles molecular dynamics calculations and analyzed the pair-correlation functions, electronic densities of states, and Bader charges and volumes of the 3d transition metals dissolved in the liquid LBE as impurities. The calculations show that the 4s and 3d orbitals of the 3d impurity atoms largely interact with the 6p band of the LBE, which generates bonding orbitals. We suggest that the high stability of 3d metals in the liquid LBE is caused by the interactions of the 4s and 3d orbitals with the 6p band. Spin polarization is induced by V, Cr, Mn, Fe and Co impurity atoms in a similar manner to the Slater-Pauling curve of solid transition metals, which exhibits a downward shift in the atomic number by approximately two. Based on the degree of spin polarization and the shifted trend of the Slater-Pauling curve, we suggest that Ni exhibits a higher solubility than Cr and Fe because of the differences in their interaction strengths between their 3d orbitals and the 6p band. In addition, the 4s and 3d orbitals of the 3d impurity atoms were found to interact more favorably with the Bi 6p band than the Pb 6p band, which is consistent with the fact that liquid Bi is more corrosive to steels than is liquid Pb.
Shin, H-J; Song, J H; Jung, J-Y; Kwak, Y-K; Kay, C S; Kang, Y-N; Choi, B O; Jang, H S
2013-01-01
Objective: To evaluate the accuracy of pencil beam calculation (PBC) and Monte Carlo calculation (MCC) for dynamic arc therapy (DAT) in a cylindrically shaped homogenous phantom, by comparing the two plans with an ion chamber, a film and a three-dimensional (3D) volumetric dosemeter. Methods: For this study, an in-house phantom was constructed, and the PBC and MCC plans for DAT were performed using iPlan® RT (BrainLAB®, Heimstetten, Germany). The A16 micro ion chamber (Standard Imaging, Middleton, WI), Gafchromic® EBT2 film (International Specialty Products, Wayne, NJ) and ArcCHECK™ (Sun Nuclear, Melbourne, FL) were used for measurements. For comparison with each plan, two-dimensional (2D) and 3D gamma analyses were performed using 3%/3 mm and 2%/2 mm criteria. Results: The difference between the PBC and MCC plans using 2D and 3D gamma analyses was found to be 7.85% and 28.8%, respectively. The ion chamber and 2D dose distribution measurements did not exhibit this difference revealed by the comparison between the PBC and MCC plans. However, the 3D assessment showed a significant difference between the PBC and MCC (62.7% for PBC vs 93.4% for MCC, p = 0.034). Conclusion: Evaluation using a 3D volumetric dosemeter can be clinically useful for delivery quality assurance (QA), and the MCC should be used to achieve the most reliable dose calculation for DAT. Advances in knowledge: (1) The DAT plan calculated using the PBC has a limitation in the calculation methods, and a 3D volumetric dosemeter was found to be an adequate tool for delivery QA of DAT. (2) The MCC was superior to PBC in terms of the accuracy in dose calculation for DAT even in the homogenous condition. PMID:24234583
Strategy and software for the statistical spatial analysis of 3D intracellular distributions.
Biot, Eric; Crowell, Elizabeth; Burguet, Jasmine; Höfte, Herman; Vernhettes, Samantha; Andrey, Philippe
2016-07-01
The localization of proteins in specific domains or compartments in the 3D cellular space is essential for many fundamental processes in eukaryotic cells. Deciphering spatial organization principles within cells is a challenging task, in particular because of the large morphological variations between individual cells. We present here an approach for normalizing variations in cell morphology and for statistically analyzing spatial distributions of intracellular compartments from collections of 3D images. The method relies on the processing and analysis of 3D geometrical models that are generated from image stacks and that are used to build representations at progressively increasing levels of integration, ultimately revealing statistical significant traits of spatial distributions. To make this methodology widely available to end-users, we implemented our algorithmic pipeline into a user-friendly, multi-platform, and freely available software. To validate our approach, we generated 3D statistical maps of endomembrane compartments at subcellular resolution within an average epidermal root cell from collections of image stacks. This revealed unsuspected polar distribution patterns of organelles that were not detectable in individual images. By reversing the classical 'measure-then-average' paradigm, one major benefit of the proposed strategy is the production and display of statistical 3D representations of spatial organizations, thus fully preserving the spatial dimension of image data and at the same time allowing their integration over individual observations. The approach and software are generic and should be of general interest for experimental and modeling studies of spatial organizations at multiple scales (subcellular, cellular, tissular) in biological systems. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.
Zhang, Zhao; Liu, Juan; Jia, Jia; Li, Xin; Han, Jian; Hu, Bin; Wang, Yongtian
2013-08-01
Heavy computational load of computer-generated hologram (CGH) and imprecise intensity modulation of 3D images are crucial problems in dynamic holographic display. The nonuniform sampling method is proposed to speed up CGH generation and precisely modulate the reconstructed intensities of phase-only CGH. The proposed method can eliminate the redundant information properly, where 70% reduction in the storage amount can be reached when it is combined with the novel lookup table method. Multigrayscale modulation of reconstructed 3D images can be achieved successfully. Numerical simulations and optical experiments are performed, and both are in good agreement. It is believed that the proposed method can be used in 3D dynamic holographic display.
Measurement of strain distributions in mouse femora with 3D-digital speckle pattern interferometry
NASA Astrophysics Data System (ADS)
Yang, Lianxiang; Zhang, Ping; Liu, Sheng; Samala, Praveen R.; Su, Min; Yokota, Hiroki
2007-08-01
Bone is a mechanosensitive tissue that adapts its mass, architecture and mechanical properties to external loading. Appropriate mechanical loads offer an effective means to stimulate bone remodeling and prevent bone loss. A role of in situ strain in bone is considered essential in enhancement of bone formation, and establishing a quantitative relationship between 3D strain distributions and a rate of local bone formation is important. Digital speckle pattern interferometry (DSPI) can achieve whole-field, non-contacting measurements of microscopic deformation for high-resolution determination of 3D strain distributions. However, the current system does not allow us to derive accurate strain distributions because of complex surface contours inherent to biological samples. Through development of a custom-made piezoelectric loading device as well as a new DSPI-based force calibration system, we built an advanced DSPI system and integrated local contour information to deformation data. Using a mouse femur in response to a knee loading modality as a model system, we determined 3D strain distributions and discussed effectiveness and limitations of the described system.
NASA Astrophysics Data System (ADS)
Akhundov, V. M.
2012-07-01
A method for calculating thin shells with one or more unidirectional layers is developed on the basis of 3D deformation models of fiber-reinforced materials at small and large deformations. Contrary to the shell model, the 3D model of shells, which is based on 3D governing equations, allows one to solve the problems on contact interaction of shells between themselves or with other bodies. The use of an applied theory of fibrous materials as a 3D deformation model is considered. The validity of the method is confirmed by using the applied theory in solving the problem on blowing of a rubber-cord diaphragm of toroidal form used in the tire production technology.
HEMP 3D -- a finite difference program for calculating elastic-plastic flow
Wilkins, M.L.
1993-05-26
The HEMP 3D program can be used to solve problems in solid mechanics involving dynamic plasticity and time dependent material behavior and problems in gas dynamics. The equations of motion, the conservation equations, and the constitutive relations are solved by finite difference methods following the format of the HEMP computer simulation program formulated in two space dimensions and time. Presented here is an update of the 1975 report on the HEMP 3D numerical technique. The present report includes the sliding surface routines programmed by Robert Gulliford.
NASA Astrophysics Data System (ADS)
Choi, S.; Kim, C.; Kim, H. R.; Park, C.; Park, H. Y.
2015-12-01
We performed the marine magnetic and the bathymetry survey in the Lau basin for finding the submarine hydrothermal deposits in October 2009. We acquired magnetic and bathymetry datasets by using Overhouser Proton Magnetometer SeaSPY(Marine Magnetics Co.) and Multi-Beam Echo Sounder EM120(Kongsberg Co.). We conducted the data processing to obtain detailed seabed topography, magnetic anomaly and reduction to the pole(RTP). The Lau basin is one of the youngest back-arc basins in the Southwest Pacific. This region was a lot of hydrothermal activities and hydrothermal deposits. In particular, Tofua Arc(TA) in the Lau basin consists of various and complex stratovolcanos(from Massoth et al., 2007).), We calculated the magnetic susceptibility distribution of the TA19-1 seamount(longitude:176°23.5'W, latitude: 22°42.5'W)area using the RTP data by 3-D magnetic inversion from Jung's previous study(2013). Based on 2D 'compact gravity inversion' by Last & Kubik(1983), we expend it to the 3D algorithm using iterative reweighted least squares method with some weight matrices. The used weight matrices are two types: 1) the minimum gradient support(MGS) that controls the spatial distribution of the solution from Porniaguine and Zhdanov(1999); 2) the depth weight that are used according to the shape of subsurface structures. From the modeling, we derived the appropriate scale factor for the use of depth weight and setting magnetic susceptibility. Furthermore, we have to enter a very small error value to control the computation of the singular point of the inversion model that was able to be easily calculated for modeling. In addition, we applied separately weighted value for the correct shape and depth of the magnetic source. We selected the best results model by change to converge of RMS. Compared between the final modeled result and RTP values in this study, they are generally similar to the each other. But the input values and the modeled values have slightly little difference
Wang, Wenjing; Qiu, Rui; Ren, Li; Liu, Huan; Wu, Zhen; Li, Chunyan; Niu, Yantao; Li, Junli
2017-06-01
At present, the Chinese specification for testing of quality control in x-ray mammography is based on a simple breast model, and does not consider the glandular tissue distribution in the breast. In order to more precisely estimate the mean glandular dose (MGD) in mammography for Chinese women, a three-dimensional (3D) detailed breast model based on realistic structures in the breast and Chinese female breast parameters was built and applied in this study. To characterize the Chinese female breast, Chinese female breast parameters including breast size, compressed breast thickness (CBT), and glandular content were investigated in this study. A mathematical model with the detailed breast structures was constructed based on the Chinese female breast parameters. The mathematical model was then converted to a voxel model with voxels. The voxel model was compressed in craniocaudal (CC) view to obtain a deformation model. The compressed breast model was combined with the Chinese reference adult female whole-body voxel phantom (CRAF) to study the effects of backscatter from the female body. Monte Carlo simulations of the glandular dose in mammography were performed with Geant 4. The glandular tissue dose conversion coefficients for breasts with different glandular contents (5%, 25%, 50%, 75%, and 100% glandularity) and CBTs (3 cm, 4 cm, 5 cm, and 6 cm) were calculated, respectively, at various x-ray tube voltages (25 kV, 28 kV, 30 kV, 32 kV, and 35 kV) for various target/filter combinations (Mo/Mo, Mo/Rh, Rh/Rh, and W/Rh). A series of glandular tissue dose conversion coefficients for dose estimation in mammography were calculated. The conversion coefficients calculated in this study were compared with those estimated with the simple breast model. A discrepancy of 5.4-38.0% was observed. This was consistent with the results obtained from the realistic breast models in the literature. A 3D detailed breast model with realistic structures in the breast was constructed
Algorithm Calculates Cumulative Poisson Distribution
NASA Technical Reports Server (NTRS)
Bowerman, Paul N.; Nolty, Robert C.; Scheuer, Ernest M.
1992-01-01
Algorithm calculates accurate values of cumulative Poisson distribution under conditions where other algorithms fail because numbers are so small (underflow) or so large (overflow) that computer cannot process them. Factors inserted temporarily to prevent underflow and overflow. Implemented in CUMPOIS computer program described in "Cumulative Poisson Distribution Program" (NPO-17714).
The research of 3D visualization techniques for the test of laser energy distribution
NASA Astrophysics Data System (ADS)
Liu, Lixin; Wang, Bo
2013-07-01
In the process of laser transmission in the atmosphere, the complexity and instability of the atmospheric composition that seriously interfere with, even change, the performance of the laser beam. The image of laser energy distribution can be captured and analyzed through infrared CCD and digital image processing technology. The basic features of laser energy density distribution, such as the location and power of the peak point and other basic parameters could be acquired; laser energy density distribution can display in real time continuous multi-frame; the 3D visualization of pseudo-color for laser energy density distribution could be displayed, that reflect the relative size and position of the energy distribution in the different regions of the laser spot, using the VC++, windows APIs and OpenGL programming. The laser energy density distribution can be observed from all angles.
The 3D scanner for measuring body surface area: a simplified calculation in the Chinese adult.
Yu, Chi-Yuan; Lo, Yu-Hung; Chiou, Wen-Ko
2003-05-01
Three-dimensional (3D) surface anthropometry enables us to extend the study to 3D geometry and morphology of mainly external human body tissues. A model is presented for estimation of human body surface area (BSA), which is identical in form to the one proposed in 1916 by DuBois and DuBois is presented. The purpose of this study is to measure BSA, using 3D scanner, and to derive a simple BSA estimation formula for the Chinese adults. In as little as 12s, the Chang Gung Whole-Body Scanner (CGWBS) allows you to capture the shape of the entire human body. The total error in BSA measurement due to scanning measurement and software computational error is less than 1%. The 3D anthropometric measures in a healthy population (n=3951) were investigated, and the results were used to derive a BSA estimation formula. The results seem to be comparable to previous data that measured BSA using traditional methods. The BSA estimation model of this study also validated using 300 new measurements along with the formulae proposed in previous researches. The result suggests that our formula better fits our adults.
3D mapping of crystallographic phase distribution using energy-selective neutron tomography.
Woracek, Robin; Penumadu, Dayakar; Kardjilov, Nikolay; Hilger, Andre; Boin, Mirko; Banhart, John; Manke, Ingo
2014-06-25
Nondestructive 3D mapping of crystallographic phases is introduced providing distribution of phase fractions within the bulk (centimeter range) of samples with micrometer-scale resolution. The novel neutron tomography based technique overcomes critical limitations of existing techniques and offers a wide range of potential applications. It is demonstrated for steel samples exhibiting phase transformation after being subjected to tensile and torsional deformation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Electromagnetic Response Inversion for a 3D Distribution of Conductivity/Dielect
Newman, Gregory
2001-10-24
NLCGCS inverts electromagnetic responses for a 3D distribution of electrical conductivity and dielectric permittivity within the earth for geophysical applications using single processor computers. The software comes bundled with a graphical user interface to aid in model construction and analysis and viewing of earth images. The solution employs both dipole and finite size source configurations for harmonic oscillatory sources. A new nonlinear preconditioner is included in the solution to speed up solution convergence.
A Gaussian Distribution for Refined DT Invariants and 3D Partitions
NASA Astrophysics Data System (ADS)
Morrison, Andrew
2014-11-01
We show that the refined Donaldson-Thomas invariants of , suitably normalized, have a Gaussian distribution as limit law. Combinatorially, these numbers are given by weighted counts of 3D partitions. Our technique is to use the Hardy-Littlewood circle method to analyze the bivariate asymptotics of a q-deformation of MacMahon's function. The proof is based on that of E.M. Wright, who explored the single variable case.
2012-08-01
Michael D. Uchic and Michael Groeber Metals Branch Structural Materials Division Megna Shah UES, Inc. Gregory Loughnane, Raghavan Srinivasan...AUTHOR(S) Michael D. Uchic and Michael Groeber (AFRL/RXCM) Megna Shah (UES, Inc.) Gregory Loughnane, Raghavan Srinivasan, and Ramana Grandhi (Wright...effect of 3D spatial resolution on the accuracy of microstructural distributions Gregory Loughnane 1 , Michael Groeber 2 , Michael Uchic 2 , Matthew
Beyond the Map: Enamel Distribution Characterized from 3D Dental Topography
Thiery, Ghislain; Lazzari, Vincent; Ramdarshan, Anusha; Guy, Franck
2017-01-01
Enamel thickness is highly susceptible to natural selection because thick enamel may prevent tooth failure. Consequently, it has been suggested that primates consuming stress-limited food on a regular basis would have thick-enameled molars in comparison to primates consuming soft food. Furthermore, the spatial distribution of enamel over a single tooth crown is not homogeneous, and thick enamel is expected to be more unevenly distributed in durophagous primates. Still, a proper methodology to quantitatively characterize enamel 3D distribution and test this hypothesis is yet to be developed. Unworn to slightly worn upper second molars belonging to 32 species of anthropoid primates and corresponding to a wide range of diets were digitized using high resolution microcomputed tomography. In addition, their durophagous ability was scored from existing literature. 3D average and relative enamel thickness were computed based on the volumetric reconstruction of the enamel cap. Geometric estimates of their average and relative enamel-dentine distance were also computed using 3D dental topography. Both methods gave different estimations of average and relative enamel thickness. This study also introduces pachymetric profiles, a method inspired from traditional topography to graphically characterize thick enamel distribution. Pachymetric profiles and topographic maps of enamel-dentine distance are combined to assess the evenness of thick enamel distribution. Both pachymetric profiles and topographic maps indicate that thick enamel is not significantly more unevenly distributed in durophagous species, except in Cercopithecidae. In this family, durophagous species such as mangabeys are characterized by an uneven thick enamel and high pachymetric profile slopes at the average enamel thickness, whereas non-durophagous species such as colobine monkeys are not. These results indicate that the distribution of thick enamel follows different patterns across anthropoids. Primates might
3D Mass Spectrometry Imaging Reveals a Very Heterogeneous Drug Distribution in Tumors
Giordano, S.; Morosi, L.; Veglianese, P.; Licandro, S. A.; Frapolli, R.; Zucchetti, M.; Cappelletti, G.; Falciola, L.; Pifferi, V.; Visentin, S.; D’Incalci, M.; Davoli, E.
2016-01-01
Mass Spectrometry Imaging (MSI) is a widespread technique used to qualitatively describe in two dimensions the distribution of endogenous or exogenous compounds within tissue sections. Absolute quantification of drugs using MSI is a recent challenge that just in the last years has started to be addressed. Starting from a two dimensional MSI protocol, we developed a three-dimensional pipeline to study drug penetration in tumors and to develop a new drug quantification method by MALDI MSI. Paclitaxel distribution and concentration in different tumors were measured in a 3D model of Malignant Pleural Mesothelioma (MPM), which is known to be a very heterogeneous neoplasm, highly resistant to different drugs. The 3D computational reconstruction allows an accurate description of tumor PTX penetration, adding information about the heterogeneity of tumor drug distribution due to the complex microenvironment. The use of an internal standard, homogenously sprayed on tissue slices, ensures quantitative results that are similar to those obtained using HPLC. The 3D model gives important information about the drug concentration in different tumor sub-volumes and shows that the great part of each tumor is not reached by the drug, suggesting the concept of pseudo-resistance as a further explanation for ineffective therapies and tumors relapse. PMID:27841316
Estimating Fiber Orientation Distribution Functions in 3D-Polarized Light Imaging
Axer, Markus; Strohmer, Sven; Gräßel, David; Bücker, Oliver; Dohmen, Melanie; Reckfort, Julia; Zilles, Karl; Amunts, Katrin
2016-01-01
Research of the human brain connectome requires multiscale approaches derived from independent imaging methods ideally applied to the same object. Hence, comprehensible strategies for data integration across modalities and across scales are essential. We have successfully established a concept to bridge the spatial scales from microscopic fiber orientation measurements based on 3D-Polarized Light Imaging (3D-PLI) to meso- or macroscopic dimensions. By creating orientation distribution functions (pliODFs) from high-resolution vector data via series expansion with spherical harmonics utilizing high performance computing and supercomputing technologies, data fusion with Diffusion Magnetic Resonance Imaging has become feasible, even for a large-scale dataset such as the human brain. Validation of our approach was done effectively by means of two types of datasets that were transferred from fiber orientation maps into pliODFs: simulated 3D-PLI data showing artificial, but clearly defined fiber patterns and real 3D-PLI data derived from sections through the human brain and the brain of a hooded seal. PMID:27147981
NASA Astrophysics Data System (ADS)
Yi, Longtao; Qin, Min; Wang, Kai; Lin, Xue; Peng, Shiqi; Sun, Tianxi; Liu, Zhiguo
2016-09-01
Confocal three-dimensional micro-X-ray fluorescence (3D-XRF) is a good surface analysis technology widely used to analyse elements and elemental distributions. However, it has rarely been applied to analyse surface topography and 3D elemental mapping in surface morphology. In this study, a surface adaptive algorithm using the progressive approximation method was designed to obtain surface topography. A series of 3D elemental mapping analyses in surface morphology were performed in laboratories to analyse painted pottery fragments from the Majiayao Culture (3300-2900 BC). To the best of our knowledge, for the first time, sample surface topography and 3D elemental mapping were simultaneously obtained. Besides, component and depth analyses were also performed using synchrotron radiation confocal 3D-XRF and tabletop confocal 3D-XRF, respectively. The depth profiles showed that the sample has a layered structure. The 3D elemental mapping showed that the red pigment, black pigment, and pottery coat contain a large amount of Fe, Mn, and Ca, respectively. From the 3D elemental mapping analyses at different depths, a 3D rendering was obtained, clearly showing the 3D distributions of the red pigment, black pigment, and pottery coat. Compared with conventional 3D scanning, this method is time-efficient for analysing 3D elemental distributions and hence especially suitable for samples with non-flat surfaces.
Spatial 3D distribution of soil organic carbon under different land use types.
Amirian Chakan, A; Taghizadeh-Mehrjardi, R; Kerry, R; Kumar, S; Khordehbin, S; Yusefi Khanghah, S
2017-03-01
Soil organic carbon (SOC) has been assessed in three dimension (3D) in several studies, but little is known about the combined effects of land use and soil depth on SOC stocks in semi-arid areas. This paper investigates the 3D distribution of SOC to a depth of 1 m in a 4600-ha area in southeastern Iran with different land uses under the irrigated farming (IF), dry farming (DF), orchards (Or), range plants on the Gachsaran formation (RaG), and range plants on a quaternary formation (RaQ). Predictions were made using the artificial neural networks (ANNs), regression trees (RTs), and spline functions with auxiliary covariates derived from a digital elevation model (DEM), the Landsat 8 imagery, and land use types. Correlation analysis showed that the main predictors for SOC in the topsoil were covariates derived from the imagery; however, for the lower depths, covariates derived from both the DEM and imagery were important. ANNs showed more efficiency than did RTs in predicting SOC. The results showed that 3D distribution of SOC was significantly affected by land use types. SOC stocks of soils under Or and IF were significantly higher than those under DF, RaG, and RaQ. The SOC below 30 cm accounted for about 59% of the total soil stock. Results showed that depth functions combined with digital soil mapping techniques provide a promising approach to evaluate 3D SOC distribution under different land uses in semi-arid regions and could be used to assess changes in time to determine appropriate management strategies.
Visser, R.; Wauben, D. J. L.; Godart, J.; Langendijk, J. A.; Veld, A. A. van't; Korevaar, E. W.; Groot, M. de
2013-02-15
Purpose: Advanced radiotherapy treatments require appropriate quality assurance (QA) to verify 3D dose distributions. Moreover, increase in patient numbers demand efficient QA-methods. In this study, a time efficient method that combines model-based QA and measurement-based QA was developed; i.e., the hybrid-QA. The purpose of this study was to determine the reliability of the model-based QA and to evaluate time efficiency of the hybrid-QA method. Methods: Accuracy of the model-based QA was determined by comparison of COMPASS calculated dose with Monte Carlo calculations for heterogeneous media. In total, 330 intensity modulated radiation therapy (IMRT) treatment plans were evaluated based on the mean gamma index (GI) with criteria of 3%/3mm and classification of PASS (GI {<=} 0.4), EVAL (0.4 < GI > 0.6), and FAIL (GI {>=} 0.6). Agreement between model-based QA and measurement-based QA was determined for 48 treatment plans, and linac stability was verified for 15 months. Finally, time efficiency improvement of the hybrid-QA was quantified for four representative treatment plans. Results: COMPASS calculated dose was in agreement with Monte Carlo dose, with a maximum error of 3.2% in heterogeneous media with high density (2.4 g/cm{sup 3}). Hybrid-QA results for IMRT treatment plans showed an excellent PASS rate of 98% for all cases. Model-based QA was in agreement with measurement-based QA, as shown by a minimal difference in GI of 0.03 {+-} 0.08. Linac stability was high with an average GI of 0.28 {+-} 0.04. The hybrid-QA method resulted in a time efficiency improvement of 15 min per treatment plan QA compared to measurement-based QA. Conclusions: The hybrid-QA method is adequate for efficient and accurate 3D dose verification. It combines time efficiency of model-based QA with reliability of measurement-based QA and is suitable for implementation within any radiotherapy department.
Volatile transport on inhomogeneous surfaces: II. Numerical calculations (VT3D)
NASA Astrophysics Data System (ADS)
Young, Leslie A.
2017-03-01
Several distant icy worlds have atmospheres that are in vapor-pressure equilibrium with their surface volatiles, including Pluto, Triton, and, probably, several large KBOs near perihelion. Studies of the volatile and thermal evolution of these have been limited by computational speed, especially for models that treat surfaces that vary with both latitude and longitude. In order to expedite such work, I present a new numerical model for the seasonal behavior of Pluto and Triton which (i) uses initial conditions that improve convergence, (ii) uses an expedient method for handling the transition between global and non-global atmospheres, (iii) includes local conservation of energy and global conservation of mass to partition energy between heating, conduction, and sublimation or condensation, (iv) uses time-stepping algorithms that ensure stability while allowing larger timesteps, and (v) can include longitudinal variability. This model, called VT3D, has been used in Young (2012a, 2012b), Young (2013), Olkin et al. (2015), Young and McKinnon (2013), and French et al. (2015). Many elements of VT3D can be used independently. For example, VT3D can also be used to speed up thermophysical models (Spencer et al., 1989) for bodies without volatiles. Code implementation is included in the supplemental materials and is available from the author.
Quantum key distribution for security guarantees over QoS-driven 3D satellite networks
NASA Astrophysics Data System (ADS)
Wang, Ping; Zhang, Xi; Chen, Genshe; Pham, Khanh; Blasch, Erik
2014-06-01
In recent years, quantum-based communication is emerging as a new technique for ensuring secured communications because it can guarantee absolute security between two different remote entities. Quantum communication performs the transmission and exchange of quantum information among distant nodes within a network. Quantum key distribution (QKD) is a methodology for generating and distributing random encryption keys using the principles of quantum physics. In this paper, we investigate the techniques on how to efficiently use QKD in 3D satellite networks and propose an effective method to overcome its communications-distance limitations. In order to implement secured and reliable communications over wireless satellite links, we develop a free-space quantum channel model in satellite communication networks. To enlarge the communications distances over 3D satellite networks, we propose to employ the intermediate nodes to relay the unconditional keys and guarantee the Quantum Bit Error Rate (QBER) for security requirement over 3D satellite networks. We also propose the communication model for QKD security-Quality of Service (QoS) guarantee and an adaptive cooperative routing selection scheme to optimize the throughput performance of QKD-based satellite communications networks. The obtained simulation results verify our proposed schemes.
Generating 3D depletion distribution in an achromatic single-channel monolithic system
NASA Astrophysics Data System (ADS)
Fallet, Clement; Lindberg, Arvid; Sirat, Gabriel Y.
2016-02-01
Recent developments have shown that conical diffraction by a biaxial crystal can create a vortex beam for use in 2D STED microscopy. It has been shown that this concept can be extended and also generate the depletion distributions used for 3D STED microscopy. A single beam passes through a biaxial crystal that creates two co-propagating, co-localized beams; the first one is used for lateral depletion, and the other one for axial depletion. The two beams are crossed-polarized and thus do not interfere. We will show that the 3D distribution can be made achromatic, i.e. several depletion wavelengths can travel through a common path and still be shaped into the appropriate pattern by optimizing the geometry of the system. This system enables true one-channel 3D depletion at multiple wavelengths ranging from 580nm to 770nm, thus covering most of the conventional depletion wavelengths currently used. Preliminary results of depletion PSFs will be presented and the advantages and limitations of this system will be discussed as well as the experimental considerations required to successfully obtain the desired PSFs.
Accurate Automatic Detection of Densely Distributed Cell Nuclei in 3D Space
Tokunaga, Terumasa; Kanamori, Manami; Teramoto, Takayuki; Jang, Moon Sun; Kuge, Sayuri; Ishihara, Takeshi; Yoshida, Ryo; Iino, Yuichi
2016-01-01
To measure the activity of neurons using whole-brain activity imaging, precise detection of each neuron or its nucleus is required. In the head region of the nematode C. elegans, the neuronal cell bodies are distributed densely in three-dimensional (3D) space. However, no existing computational methods of image analysis can separate them with sufficient accuracy. Here we propose a highly accurate segmentation method based on the curvatures of the iso-intensity surfaces. To obtain accurate positions of nuclei, we also developed a new procedure for least squares fitting with a Gaussian mixture model. Combining these methods enables accurate detection of densely distributed cell nuclei in a 3D space. The proposed method was implemented as a graphical user interface program that allows visualization and correction of the results of automatic detection. Additionally, the proposed method was applied to time-lapse 3D calcium imaging data, and most of the nuclei in the images were successfully tracked and measured. PMID:27271939
Efficient 3-D medical image registration using a distributed blackboard architecture.
Tait, Roger J; Schaefer, Gerald; Hopgood, Adrian A; Zhu, Shao Ying
2006-01-01
A major drawback of 3-D medical image registration techniques is the performance bottleneck associated with re-sampling and similarity computation. Such bottlenecks limit registration applications in clinical situations where fast execution times are required and become particularly apparent in the case of registering 3-D data sets. In this paper a novel framework for high performance intensity-based volume registration is presented. Geometric alignment of both reference and sensed volume sets is achieved through a combination of scaling, translation, and rotation. Crucially, resampling and similarity computation is performed intelligently by a set of knowledge sources. The knowledge sources work in parallel and communicate with each other by means of a distributed blackboard architecture. Partitioning of the blackboard is used to balance communication and processing workloads. Large-scale registrations with substantial speedups, when compared with a conventional implementation, have been demonstrated.
NASA Technical Reports Server (NTRS)
Scargle, Jeffrey D.; Way, M. J.; Gazis, P. G.
2017-01-01
We demonstrate the effectiveness of a relatively straightforward analysis of the complex 3D Fourier transform of galaxy coordinates derived from redshift surveys. Numerical demonstrations of this approach are carried out on a volume-limited sample of the Sloan Digital Sky Survey redshift survey. The direct unbinned transform yields a complex 3D data cube quite similar to that from the Fast Fourier Transform of finely binned galaxy positions. In both cases, deconvolution of the sampling window function yields estimates of the true transform. Simple power spectrum estimates from these transforms are roughly consistent with those using more elaborate methods. The complex Fourier transform characterizes spatial distributional properties beyond the power spectrum in a manner different from (and we argue is more easily interpreted than) the conventional multipoint hierarchy. We identify some threads of modern large-scale inference methodology that will presumably yield detections in new wider and deeper surveys.
Analysis of the KROTOS KFC test by coupling X-Ray image analysis and MC3D calculations
Brayer, C.; Charton, A.; Grishchenko, D.; Fouquart, P.; Bullado, Y.; Compagnon, F.; Correggio, P.; Cassiaut-Louis, N.; Piluso, P.
2012-07-01
During a hypothetical severe accident sequence in a Pressurized Water Reactor (PWR), the hot molten materials (corium) issuing from the degraded reactor core may generate a steam explosion if they come in contact with water and may damage the structures and threaten the reactor integrity. The SERENA program is an international OECD project that aims at helping the understanding of this phenomenon also called Fuel Coolant Interaction (FCI) by providing data. CEA takes part in this program by performing tests in its KROTOS facility where steam explosions using prototypic corium can be triggered. Data about the different phases in the premixing are extracted from the KROTOS X-Ray radioscopy images by using KIWI software (KROTOS Image analysis of Water-corium Interaction) currently developed by CEA. The MC3D code, developed by IRSN, is a thermal-hydraulic multiphase code mainly dedicated to FCI studies. It is composed of two applications: premixing and explosion. An overall FCI calculation with MC3D requires a premixing calculation followed by an explosion calculation. The present paper proposes an alternative approach in which all the features of the premixing are extracted from the X-Ray pictures using the KIWI software and transferred to an MC3D dataset for a direct simulation of the explosion. The main hypothesis are discussed as well as the first explosion results obtained with MC3D for the KROTOS KFC test. These results are rather encouraging and are analyzed on the basis of comparisons with the experimental data. (authors)
Spectral element method for band-structure calculations of 3D phononic crystals
NASA Astrophysics Data System (ADS)
Shi, Linlin; Liu, Na; Zhou, Jianyang; Zhou, Yuanguo; Wang, Jiamin; Huo Liu, Qing
2016-11-01
The spectral element method (SEM) is a special kind of high-order finite element method (FEM) which combines the flexibility of a finite element method with the accuracy of a spectral method. In contrast to the traditional FEM, the SEM exhibits advantages in the high-order accuracy as the error decreases exponentially with the increase of interpolation degree by employing the Gauss-Lobatto-Legendre (GLL) polynomials as basis functions. In this study, the spectral element method is developed for the first time for the determination of band structures of 3D isotropic/anisotropic phononic crystals (PCs). Based on the Bloch theorem, we present a novel, intuitive discretization formulation for Navier equation in the SEM scheme for periodic media. By virtue of using the orthogonal Legendre polynomials, the generalized eigenvalue problem is converted to a regular one in our SEM implementation to improve the efficiency. Besides, according to the specific geometry structure, 8-node and 27-node hexahedral elements as well as an analytic mesh have been used to accurately capture curved PC models in our SEM scheme. To verify its accuracy and efficiency, this study analyses the phononic-crystal plates with square and triangular lattice arrangements, and the 3D cubic phononic crystals consisting of simple cubic (SC), bulk central cubic (BCC) and faced central cubic (FCC) lattices with isotropic or anisotropic scatters. All the numerical results considered demonstrate that SEM is superior to the conventional FEM and can be an efficient alternative method for accurate determination of band structures of 3D phononic crystals.
3D map distribution of metallic nanoparticles in whole cells using MeV ion microscopy.
Vasco, M S; Alves, L C; Corregidor, V; Correia, D; Godinho, C P; Sá-Correia, I; Bettiol, A; Watt, F; Pinheiro, T
2017-08-01
In this work, a new tool was developed, the MORIA program that readily translates Rutherford backscattering spectrometry (RBS) output data into visual information, creating a display of the distribution of elements in a true three-dimensional (3D) environment. The program methodology is illustrated with the analysis of yeast Saccharomyces cerevisiae cells, exposed to copper oxide nanoparticles (CuO-NP) and HeLa cells in the presence of gold nanoparticles (Au-NP), using different beam species, energies and nuclear microscopy systems. Results demonstrate that for both cell types, the NP internalization can be clearly perceived. The 3D models of the distribution of CuO-NP in S. cerevisiae cells indicate the nonuniform distribution of NP in the cellular environment and a relevant confinement of CuO-NP to the cell wall. This suggests the impenetrability of certain cellular organelles or compartments for NP. By contrast, using a high-resolution ion beam system, discretized agglomerates of Au-NP were visualized inside the HeLa cell. This is consistent with the mechanism of entry of these NPs in the cellular space by endocytosis enclosed in endosomal vesicles. This approach shows RBS to be a powerful imaging technique assigning to nuclear microscopy unparalleled potential to assess nanoparticle distribution inside the cellular volume. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.
3-D heat transfer computer calculations of the performance of the IAEA's air-bath calorimeters
Elias, E.; Kaizermann, S.; Perry, R.B.; Fiarman, S.
1989-01-01
A three dimensional (3-D) heat transfer computer code was developed to study and optimize the design parameters and to better understand the performance characteristics of the IAEA's air-bath calorimeters. The computer model accounts for heat conduction and radiation in the complex materials of the calorimeter and for heat convection and radiation at its outer surface. The temperature servo controller is modelled as an integral part of the heat balance equations in the system. The model predictions will be validated against test data using the ANL bulk calorimeter. 11 refs., 6 figs.
PARALLEL 3-D SPACE CHARGE CALCULATIONS IN THE UNIFIED ACCELERATOR LIBRARY.
D'IMPERIO, N.L.; LUCCIO, A.U.; MALITSKY, N.
2006-06-26
The paper presents the integration of the SIMBAD space charge module in the UAL framework. SIMBAD is a Particle-in-Cell (PIC) code. Its 3-D Parallel approach features an optimized load balancing scheme based on a genetic algorithm. The UAL framework enhances the SIMBAD standalone version with the interactive ROOT-based analysis environment and an open catalog of accelerator algorithms. The composite package addresses complex high intensity beam dynamics and has been developed as part of the FAIR SIS 100 project.
NASA Astrophysics Data System (ADS)
Haji Mohammadi, M.; Kang, S.; Sotiropoulos, F.
2011-12-01
It is well-known that meander bends impose local losses of energy to the flow in rivers. These local losses should be added together with friction loss to get the total loss of energy. In this work, we strive to develop a framework that considers the effect of bends in meandering rivers for one-dimensional (1-D) homogenous equations of flow. Our objective is to develop a simple, yet physically sound, and efficient model for carrying out engineering computations of flow through meander bends. We consider several approaches for calculating 1-D hydraulic properties of meandering rivers such as friction factor and Manning coefficient. The method of Kasper et al. (2005), which is based on channel top width, aspect ratio and radius of curvature, is adopted for further calculations. In this method, a correction is implemented in terms of local energy loss, due to helical motion and secondary currents of fluid particles driven by centrifugal force, in meanders. To validate the model, several test cases are simulated and the computed results are compared with the reported data in the literature in terms of water surface elevation, shear velocity, etc. For all cases the computed results are in reasonable agreement with the experimental data. 3-D RANS turbulent flow simulations are also carried out, using the method of Kang et al. (Adv. In Water Res., vol. 34, 2011), for different geometrical parameters of Kinoshita Rivers to determine the spatial distribution of shear stress on river bed and banks, which is the key factor in scour/deposition patterns. The 3-D solutions are then cross-sectionally averaged and compared with the respective solutions from the 1-D model. The comparisons show that the improved 1D model, which incorporates the effect of local bend loss, captures key flow parameters with reasonable accuracy. Our results also underscore the range of validity and limitations of 1D models for meander bend simulations. This work was supported by NSF Grants (as part of
Li, Heng; Liu, Wei; Park, Peter; Matney, Jason; Liao, Zhongxing; Chang, Joe; Zhang, Xiaodong; Li, Yupeng; Zhu, Ronald X
2014-09-08
The objective of this study was to evaluate and understand the systematic error between the planned three-dimensional (3D) dose and the delivered dose to patient in scanning beam proton therapy for lung tumors. Single-field and multifield optimized scanning beam proton therapy plans were generated for ten patients with stage II-III lung cancer with a mix of tumor motion and size. 3D doses in CT datasets for different respiratory phases and the time-weighted average CT, as well as the four-dimensional (4D) doses were computed for both plans. The 3D and 4D dose differences for the targets and different organs at risk were compared using dose-volume histogram (DVH) and voxel-based techniques, and correlated with the extent of tumor motion. The gross tumor volume (GTV) dose was maintained in all 3D and 4D doses, using the internal GTV override technique. The DVH and voxel-based techniques are highly correlated. The mean dose error and the standard deviation of dose error for all target volumes were both less than 1.5% for all but one patient. However, the point dose difference between the 3D and 4D doses was up to 6% for the GTV and greater than 10% for the clinical and planning target volumes. Changes in the 4D and 3D doses were not correlated with tumor motion. The planning technique (single-field or multifield optimized) did not affect the observed systematic error. In conclusion, the dose error in 3D dose calculation varies from patient to patient and does not correlate with lung tumor motion. Therefore, patient-specific evaluation of the 4D dose is important for scanning beam proton therapy for lung tumors.
3D Drop Size Distribution Extrapolation Algorithm Using a Single Disdrometer
NASA Technical Reports Server (NTRS)
Lane, John
2012-01-01
Determining the Z-R relationship (where Z is the radar reflectivity factor and R is rainfall rate) from disdrometer data has been and is a common goal of cloud physicists and radar meteorology researchers. The usefulness of this quantity has traditionally been limited since radar represents a volume measurement, while a disdrometer corresponds to a point measurement. To solve that problem, a 3D-DSD (drop-size distribution) method of determining an equivalent 3D Z-R was developed at the University of Central Florida and tested at the Kennedy Space Center, FL. Unfortunately, that method required a minimum of three disdrometers clustered together within a microscale network (.1-km separation). Since most commercial disdrometers used by the radar meteorology/cloud physics community are high-cost instruments, three disdrometers located within a microscale area is generally not a practical strategy due to the limitations of these kinds of research budgets. A relatively simple modification to the 3D-DSD algorithm provides an estimate of the 3D-DSD and therefore, a 3D Z-R measurement using a single disdrometer. The basis of the horizontal extrapolation is mass conservation of a drop size increment, employing the mass conservation equation. For vertical extrapolation, convolution of a drop size increment using raindrop terminal velocity is used. Together, these two independent extrapolation techniques provide a complete 3DDSD estimate in a volume around and above a single disdrometer. The estimation error is lowest along a vertical plane intersecting the disdrometer position in the direction of wind advection. This work demonstrates that multiple sensors are not required for successful implementation of the 3D interpolation/extrapolation algorithm. This is a great benefit since it is seldom that multiple sensors in the required spatial arrangement are available for this type of analysis. The original software (developed at the University of Central Florida, 1998.- 2000) has
3D distribution of interstellar medium in the Galaxy: Preparation for analysis of Gaia observations
Puspitarini, Lucky; Lallement, Rosine
2015-09-30
Accurate and detailed three-dimensional (3D) maps of Galactic interstellar medium (ISM) are still lacking. One way to obtain such 3D descriptions is to record a large set of individual absorption or reddening measurements toward target stars located at various known distances and directions. The inversion of these measurements using a tomographic method can produce spatial distribution of the ISM. Until recently absorption data were very limited and distances to the target stars are still uncertain, but the situation will greatly improve thanks to current and future massive stellar surveys from ground, and to Gaia mission. To prepare absorption data for inversion from a huge number of stellar spectra, automated tools are needed. We have developed various spectral analysis tools adapted to different type of spectra, early- or late- type star. We also have used diffuse interstellar bands (DIBs) to trace IS structures and kinematics. Although we do not know yet their carriers, they can be a promising tool to trace distant interstellar clouds or Galactic arms. We present some examples of the interstellar fitting and show the potentiality of DIBs in tracing the ISM. We will also briefly show and comment the latest 3D map of the local ISM which reveal nearby cloud complexes and cavities.
Stress distribution in a premolar 3D model with anisotropic and isotropic enamel.
Munari, Laís S; Cornacchia, Tulimar P M; Moreira, Allyson N; Gonçalves, Jason B; De Las Casas, Estevam B; Magalhães, Cláudia S
2015-08-01
The aim of this study was to compare the areas of stress concentration in a three-dimensional (3D) premolar tooth model with anisotropic or isotropic enamel using the finite element method. A computed tomography was imported to an image processing program to create the tooth model which was exported to a 3D modeling program. The mechanical properties and loading conditions were prescribed in Abaqus. In order to evaluate stresses, axial and oblique loads were applied simulating realistic conditions. Compression stress was observed on the side of load application, and tensile stress was observed on the opposite side. Tensile stress was concentrated mainly in the cervical region and in the alveolar insertion bone. Although stress concentration analyses of the isotropic 3D models produced similar stress distribution results when compared to the anisotropic models, tensile stress values shown by anisotropic models were smaller than the isotropic models. Oblique loads resulted in higher values of tensile stresses, which concentrate mainly in the cervical area of the tooth and in the alveolar bone insertion. Anisotropic properties must be utilized in enamel stress evaluation in non-carious cervical lesions.
An extension of the Saltykov method to quantify 3D grain size distributions in mylonites
NASA Astrophysics Data System (ADS)
Lopez-Sanchez, Marco A.; Llana-Fúnez, Sergio
2016-12-01
The estimation of 3D grain size distributions (GSDs) in mylonites is key to understanding the rheological properties of crystalline aggregates and to constraining dynamic recrystallization models. This paper investigates whether a common stereological method, the Saltykov method, is appropriate for the study of GSDs in mylonites. In addition, we present a new stereological method, named the two-step method, which estimates a lognormal probability density function describing the 3D GSD. Both methods are tested for reproducibility and accuracy using natural and synthetic data sets. The main conclusion is that both methods are accurate and simple enough to be systematically used in recrystallized aggregates with near-equant grains. The Saltykov method is particularly suitable for estimating the volume percentage of particular grain-size fractions with an absolute uncertainty of ±5 in the estimates. The two-step method is suitable for quantifying the shape of the actual 3D GSD in recrystallized rocks using a single value, the multiplicative standard deviation (MSD) parameter, and providing a precision in the estimate typically better than 5%. The novel method provides a MSD value in recrystallized quartz that differs from previous estimates based on apparent 2D GSDs, highlighting the inconvenience of using apparent GSDs for such tasks.
DVR3D: a program suite for the calculation of rotation-vibration spectra of triatomic molecules
NASA Astrophysics Data System (ADS)
Tennyson, Jonathan; Kostin, Maxim A.; Barletta, Paolo; Harris, Gregory J.; Polyansky, Oleg L.; Ramanlal, Jayesh; Zobov, Nikolai F.
2004-11-01
The DVR3D program suite calculates energy levels, wavefunctions, and where appropriate dipole transition moments, for rotating and vibrating triatomic molecules. Potential energy and, where necessary, dipole surfaces must be provided. Expectation values of geometrically defined functions can be calculated, a feature which is particularly useful for fitting potential energy surfaces. The programs use an exact (within the Born-Oppenheimer approximation) Hamiltonian and offer a choice of Jacobi or Radau internal coordinates and several body-fixed axes. Rotationally excited states are treated using an efficient two-step algorithm. The programs uses a Discrete Variable Representation (DVR) based on Gauss-Jacobi and Gauss-Laguerre quadrature for all 3 internal coordinates and thus yields a fully point-wise representation of the wavefunctions. The vibrational step uses successive diagonalisation and truncation which is implemented for a number of possible coordinate orderings. The rotational, expectation value and transition dipole programs exploit the savings offered by performing integrals on a DVR grid. The new version has been rewritten in FORTRAN 90 to exploit the dynamic array allocations and the algorithm for dipole and spectra calculations have been substantially improved. New modules allow the z-axis to be embedded perpendicular to the plane of the molecule and for the calculation of expectation values. Program summaryTitle of the program: DVR3D suite Catalogue number: ADTI Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTI Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Programming language: Fortran 90 No. of lines in distributed program, including test data, etc.: 61 574 No. of bytes in distributed program, including test data, etc.: 972 404 Distribution format: tar.gz New version summaryTitle of program: DVR3DRJZ Catalogue number: ADTB Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTB Program obtainable
Modeling spatial distribution of oxygen in 3d culture of islet beta-cells.
McReynolds, John; Wen, Yu; Li, Xiaofei; Guan, Jianjun; Jin, Sha
2017-01-01
Three-dimensional (3D) scaffold culture of pancreatic β-cell has been proven to be able to better mimic physiological conditions in the body. However, one critical issue with culturing pancreatic β-cells is that β-cells consume large amounts of oxygen, and hence insufficient oxygen supply in the culture leads to loss of β-cell mass and functions. This becomes more significant when cells are cultured in a 3D scaffold. In this study, in order to understand the effect of oxygen tension inside a cell-laden collagen culture on β-cell proliferation, a culture model with encapsulation of an oxygen-generator was established. The oxygen-generator was made by embedding hydrogen peroxide into nontoxic polydimethylsiloxane to avoid the toxicity of a chemical reaction in the β-cell culture. To examine the effectiveness of the oxygenation enabled 3D culture, the spatial-temporal distribution of oxygen tension inside a scaffold was evaluated by a mathematical modeling approach. Our simulation results indicated that an oxygenation-aided 3D culture would augment the oxygen supply required for the β-cells. Furthermore, we identified that cell seeding density and the capacity of the oxygenator are two critical parameters in the optimization of the culture. Notably, cell-laden scaffold cultures with an in situ oxygen supply significantly improved the β-cells' biological function. These β-cells possess high insulin secretion capacity. The results obtained in this work would provide valuable information for optimizing and encouraging functional β-cell cultures. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:221-228, 2017. © 2016 American Institute of Chemical Engineers.
Avery, James; Aristovich, Kirill; Low, Barney; Holder, David
2017-05-22
Electrical impedance tomography (EIT) has many promising applications in brain injury monitoring. To evaluate both instrumentation and reconstruction algorithms, experiments are first performed in head tanks. Existing methods, whilst accurate, produce a discontinuous conductivity, and are often made by hand, making it hard for other researchers to replicate. We have developed a method for constructing head tanks directly in a 3D printer. Conductivity was controlled through perforations in the skull surface, which allow for saline to pass through. Varying the diameter of the holes allowed for the conductivity to be controlled with 3% error for the target conductivity range. Taking CT and MRI segmentations as a basis, this method was employed to create an adult tank with a continuous conductivity distribution, and a neonatal tank with fontanelles. Using 3D scanning a geometric accuracy of 0.21 mm was recorded, equal to that of the precision of the 3D printer used. Differences of 6.1% ± 6.4% (n = 11 in 4 tanks) compared to simulations were recorded in c. 800 boundary voltages. This may be attributed to the morphology of the skulls increasing tortuosity effects and hole misalignment. Despite significant differences in errors between three repetitions of the neonatal tank, images of a realistic perturbation could still be reconstructed with different tanks used for the baseline and perturbation datasets. These phantoms can be reproduced by any researcher with access to a 'hobbyist' 3D printer in a matter of days. All design files have been released using an open source license to encourage reproduction and modification.
Meir, Arie; Rubinsky, Boris
2009-11-19
Medical technologies are indispensable to modern medicine. However, they have become exceedingly expensive and complex and are not available to the economically disadvantaged majority of the world population in underdeveloped as well as developed parts of the world. For example, according to the World Health Organization about two thirds of the world population does not have access to medical imaging. In this paper we introduce a new medical technology paradigm centered on wireless technology and cloud computing that was designed to overcome the problems of increasing health technology costs. We demonstrate the value of the concept with an example; the design of a wireless, distributed network and central (cloud) computing enabled three-dimensional (3-D) ultrasound system. Specifically, we demonstrate the feasibility of producing a 3-D high end ultrasound scan at a central computing facility using the raw data acquired at the remote patient site with an inexpensive low end ultrasound transducer designed for 2-D, through a mobile device and wireless connection link between them. Producing high-end 3D ultrasound images with simple low-end transducers reduces the cost of imaging by orders of magnitude. It also removes the requirement of having a highly trained imaging expert at the patient site, since the need for hand-eye coordination and the ability to reconstruct a 3-D mental image from 2-D scans, which is a necessity for high quality ultrasound imaging, is eliminated. This could enable relatively untrained medical workers in developing nations to administer imaging and a more accurate diagnosis, effectively saving the lives of people.
The 3D heat flux density distribution on a novel parabolic trough wavy absorber
NASA Astrophysics Data System (ADS)
Demagh, Yassine; Kabar, Yassine; Bordja, Lyes; Noui, Samira
2016-05-01
The non-uniform concentrated solar flux distribution on the outer surface of the absorber pipe can lead to large circumferential gradient temperature and high concentrated temperature of the absorber pipe wall, which is one of the primary causes of parabolic trough solar receiver breakdown. In this study, a novel shape of the parabolic trough absorber pipe is proposed as a solution to well homogenize the solar flux distribution, as well as, the temperature in the absorber wall. The conventional straight absorber located along the focal line of the parabola is replaced by wavy one (invention patent by Y. Demagh [1]) for which the heat flux density distribution on the outer surface varies in both axial and azimuthal directions (3D) while it varies only in the azimuthal direction on the former (2D). As far as we know, there is not previous study which has used a longitudinally wavy pipe as an absorber into the parabolic trough collector unit.
3D dose distribution measurements in brachytherapy using radiochromic gel dosimeters
NASA Astrophysics Data System (ADS)
Šolc, J.; Sochor, V.; Kačur, M.; Šmoldasová, J.
2010-07-01
The paper informs about the joint research project "Increasing cancer treatment efficacy using 3D brachytherapy" which is a three-year project carried out in cooperation with European national metrology institutes and co-funded by the European Community's Seventh Framework Program for research and technological development. The goal of the project is to improve the measurement and standardization of dose-to-water rate by brachytherapy (BT) sources. The paper gives a summary of the individual parts of the whole project and describes in more detail the task of the Czech Metrology Institute: the determination of spatial distribution of dose-to-water by BT sources using radiochromic gel dosimeters, including a new gel with suppressed diffusion. The response of irradiated gels is evaluated using the optical cone beam computed tomography (CT) technique. The characteristics of the optical CT scanner are discussed with respect to CCD camera performance and light source. The optimized composition of the new gel and its dosimetric properties are highlighted. The results show that the radiochromic gels are convenient for measuring the 3D distribution of dose-to-water and could be an alternative to current methods of dose distribution measurements.
Prediction of velocity distribution from pore structure in 3D porous media
NASA Astrophysics Data System (ADS)
AlAdwani, M. S. K. F. S.; De Anna, P.; Juanes, R.
2016-12-01
Fluid flow and particle transport through porous media are determined by the geometry of the host medium itself. Despite the fundamental importance of the velocity distribution in controlling early-time and late-time transport properties (e.g., early breakthrough and superdiffusive spreading), direct relations linking velocity distribution with the statistics of pore structure in 3D porous media have not been established yet. High velocities are controlled by the formation of channels, while low velocities are dominated by stagnation zones. Recent studies have proposed phenomenological models for the distribution of high velocities including stretched exponential and power-exponential distributions but without an underlying mechanistic or statistical physics theory. Here, we investigate the relationship between the structure of the host medium and the resulting fluid flow and particle transport properties. We extend recent work on simple 2D media consisting of circular nonoverlapping disks, and consider 3D random packs of spheres. This disordered spherical-pack arrangement can be characterized geometrically by constructing a Delaunay triangulation of the disk centers: each tetrahedron defines a pore body and each triangular face defines a pore throat. We simulate flow in the exact pore geometry at low Reynolds numbers by solving the Stokes equations and imposing a no-slip boundary condition at the boundary of each sphere. We develop a theoretical model to explain the observed distribution of the low velocities. We understand flow through the porous medium as being controlled by the pore throats, and we conceptualize flow through each pore throat as a Hagen-Poiseuille flow through a pipe of irregular shape controlled by its area and its shape factor. Despite its simplicity, the analytical predictions from the model agree well with high-resolution simulations, both in terms of velocity distribution and ensuing anomalous particle spreading.
A statistical approach to estimate the 3D size distribution of spheres from 2D size distributions
Kong, M.; Bhattacharya, R.N.; James, C.; Basu, A.
2005-01-01
Size distribution of rigidly embedded spheres in a groundmass is usually determined from measurements of the radii of the two-dimensional (2D) circular cross sections of the spheres in random flat planes of a sample, such as in thin sections or polished slabs. Several methods have been devised to find a simple factor to convert the mean of such 2D size distributions to the actual 3D mean size of the spheres without a consensus. We derive an entirely theoretical solution based on well-established probability laws and not constrained by limitations of absolute size, which indicates that the ratio of the means of measured 2D and estimated 3D grain size distribution should be r/4 (=.785). Actual 2D size distribution of the radii of submicron sized, pure Fe0 globules in lunar agglutinitic glass, determined from backscattered electron images, is tested to fit the gamma size distribution model better than the log-normal model. Numerical analysis of 2D size distributions of Fe0 globules in 9 lunar soils shows that the average mean of 2D/3D ratio is 0.84, which is very close to the theoretical value. These results converge with the ratio 0.8 that Hughes (1978) determined for millimeter-sized chondrules from empirical measurements. We recommend that a factor of 1.273 (reciprocal of 0.785) be used to convert the determined 2D mean size (radius or diameter) of a population of spheres to estimate their actual 3D size. ?? 2005 Geological Society of America.
Smulders, M; Berghman, K; Koenraads, M; Kane, J A; Krishna, K; Carter, T K; Schultheis, U
2016-08-12
The concept of comfort is one way for the growing airline market to differentiate and build customer loyalty. This work follows the idea that increasing the contact area between human and seat can have a positive effect on comfort [5, 6, 7]. To improve comfort, reduce weight and optimise space used, a human contour shaped seat shell and cushioning was developed. First the most common activities, the corresponding postures and seat inclination angles were defined. The imprints of these postures on a rescue mat were 3D scanned and an average human contour curve was defined. The outcome was transferred to a prototype seat that was used to test the effect on perceived comfort/discomfort and pressure distribution. The resulting human contour based prototype seat has comfort and discomfort scores comparable to a traditional seat. The prototype seat had a significantly lower average pressure between subjects' buttocks and the seat pan over a traditional seat. This study shows that it is possible to design a seat pan and backrest based on the different contours of study subjects using 3D scan technology. However, translating the 3D scans into a prototype seat also showed that this can only be seen as a first step; additionally biomechanical information and calculations are needed to create ergonomic seats. Furthermore, it is not possible to capture all different human shapes and postures and translate these into one human contour shape that fits all activities and all human sizes.
Janocchio--a Java applet for viewing 3D structures and calculating NMR couplings and NOEs.
Evans, David A; Bodkin, Michael J; Baker, S Richard; Sharman, Gary J
2007-07-01
We present a Java applet, based on the open source Jmol program, which allows the calculation of coupling constants and NOEs from a three-dimensional structure. The program has all the viewing features of Jmol, but adds the capability to calculate both H-H and H-C 3-bond couplings constants. In the case of H--H couplings, the Altona equation is used to perform this. The program also calculates NOEs using the full relaxation matrix approach. All these calculations are driven from a simple point and click interface. The program can calculate values for multi-structure files, and can produce input files for the conformational fitting program NAMFIS.
Calculation of ex-core physical quantities using the 3D importance functions
NASA Astrophysics Data System (ADS)
Trakas, Christos; De Laubiere, Xavier
2014-06-01
Diverse physical quantities are calculated in engineering studies with penalizing hypotheses to assure the required operation margins for each reactor. Today, these physical quantities are obtained by direct calculations from deterministic or Monte Carlo codes. The related states are critical or sub-critical. The current physical quantities are for example: the SRD counting rates (source range detector) in the sub-critical state, the IRD (intermediary range detector) and PRD (power range detector) counting rates (neutron particles only), the deposited energy in the reflector (neutron + photon particles), the fluence or the DPA (displacement per atom) in the reactor vessel (neutron particles only). The reliability of the proposed methodology is tested in the EPR reactor. The main advantage of the new methodology is the simplicity to obtain the physical quantities by an easy matrix calculation importance linked to nuclear power sources for all the cycles of the reactor. This method also allows to by-pass the direct calculations of the physical quantity of irradiated cores by Monte Carlo Codes, these calculations being impossible today (too many isotopic concentrations / MCNP5 limit). This paper presents the first feasibility study for the physical quantities calculation outside of the core by the importance method instead of the direct calculations used currently by AREVA.
Optimizing the Terzaghi Estimator of the 3D Distribution of Rock Fracture Orientations
NASA Astrophysics Data System (ADS)
Tang, Huiming; Huang, Lei; Juang, C. Hsein; Zhang, Junrong
2017-08-01
Orientation statistics are prone to bias when surveyed with the scanline mapping technique in which the observed probabilities differ, depending on the intersection angle between the fracture and the scanline. This bias leads to 1D frequency statistical data that are poorly representative of the 3D distribution. A widely accessible estimator named after Terzaghi was developed to estimate 3D frequencies from 1D biased observations, but the estimation accuracy is limited for fractures at narrow intersection angles to scanlines (termed the blind zone). Although numerous works have concentrated on accuracy with respect to the blind zone, accuracy outside the blind zone has rarely been studied. This work contributes to the limited investigations of accuracy outside the blind zone through a qualitative assessment that deploys a mathematical derivation of the Terzaghi equation in conjunction with a quantitative evaluation that uses fractures simulation and verification of natural fractures. The results show that the estimator does not provide a precise estimate of 3D distributions and that the estimation accuracy is correlated with the grid size adopted by the estimator. To explore the potential for improving accuracy, the particular grid size producing maximum accuracy is identified from 168 combinations of grid sizes and two other parameters. The results demonstrate that the 2° × 2° grid size provides maximum accuracy for the estimator in most cases when applied outside the blind zone. However, if the global sample density exceeds 0.5°-2, then maximum accuracy occurs at a grid size of 1° × 1°.
New approach to 3D electrostatic calculations for micro-pattern detectors
NASA Astrophysics Data System (ADS)
Lazić, P.; Dujmić, D.; Formaggio, J. A.; Abraham, H.; Štefancić, H.
2011-12-01
We demonstrate nearly approximation-free electrostatic calculations of micromesh detectors that can be extended to any other type of micropattern detectors. Using a newly developed Boundary Element Method called Robin Hood Method, we can easily handle objects with huge number of boundary elements (hundreds of thousands) without any compromise in numerical accuracy. In this paper we show how such calculations can be applied to Micromegas detectors by comparing electron transparencies and gains for four different types of meshes. We also demonstrate the inclusion of dielectric material by calculating the electric field around different types of dielectric spacers.
Harvey, R. W.; Chan, V. S.; Chiu, S. C.; Evans, T. E.; Rosenbluth, M. N.; Whyte, D. G.
2000-11-01
Runaway electrons are calculated to be produced during the rapid plasma cooling resulting from ''killer pellet'' injection experiments, in general agreement with observations in the DIII-D [J. L. Luxon , Plasma Physics and Controlled Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. I, p. 159] tokamak. The time-dependent dynamics of the kinetic runaway distributions are obtained with the CQL3D [R. W. Harvey and M. G. McCoy, ''The CQL3D Code,'' in Proceedings of the IAEA Technical Committee Meeting on Numerical Modeling, Montreal, 1992 (International Atomic Energy Agency, Vienna, 1992), p. 489] collisional Fokker--Planck code, including the effect of small and large angle collisions and stochastic magnetic field transport losses. The background density, temperature, and Z{sub eff} are evolved according to the KPRAD [D. G. Whyte and T. E. Evans , in Proceedings of the 24th European Conference on Controlled Fusion and Plasma Physics, Berchtesgaden, Germany (European Physical Society, Petit-Lancy, 1997), Vol. 21A, p. 1137] deposition and radiation model of pellet--plasma interactions. Three distinct runway mechanisms are apparent: (1) prompt ''hot-tail runaways'' due to the residual hot electron tail remaining from the pre-cooling phase, (2) ''knock-on'' runaways produced by large-angle Coulomb collisions on existing high energy electrons, and (3) Dreicer ''drizzle'' runaway electrons due to diffusion of electrons up to the critical velocity for electron runaway. For electron densities below {approx}1x10{sup 15}cm{sup -3}, the hot-tail runaways dominate the early time evolution, and provide the seed population for late time knock-on runaway avalanche. For small enough stochastic magnetic field transport losses, the knock-on production of electrons balances the losses at late times. For losses due to radial magnetic field perturbations in excess of {approx}0.1% of the background field, i.e., {delta}B{sub r}/B{>=}0.001, the losses
Spatial Distribution of Yarns and Mechanical Properties in 3D Braided Tubular Composites
NASA Astrophysics Data System (ADS)
Wang, Y. Q.; Wang, A. S. D.
1997-03-01
This paper outlines a method which links the following analytically simulated events in sequence: (1) braiding of a 3D preform of tubular cross-section characterized by a set of braiding parameters defining the braiding setup and braiding steps; (2) geometric description of the yarn topology in the braided preform in explicit terms of a set of topological parameters defined by the preform shape and the braiding parameters; (3) description of the exact yarn distribution after preform consolidation with a binding matrix the values of the topological parameters are related to the exterior dimensions and surface features of the consolidated preform; and (4) forecasting the mechanical properties in the final composite via a suitable micromechanics model that takes into account the spatial yarn distribution in the composite and properties of the constituents.
Numerical Calculations of 3-D High-Lift Flows and Comparison with Experiment
NASA Technical Reports Server (NTRS)
Compton, William B, III
2015-01-01
Solutions were obtained with the Navier-Stokes CFD code TLNS3D to predict the flow about the NASA Trapezoidal Wing, a high-lift wing composed of three elements: the main-wing element, a deployed leading-edge slat, and a deployed trailing-edge flap. Turbulence was modeled by the Spalart-Allmaras one-equation turbulence model. One case with massive separation was repeated using Menter's two-equation SST (Menter's Shear Stress Transport) k-omega turbulence model in an attempt to improve the agreement with experiment. The investigation was conducted at a free stream Mach number of 0.2, and at angles of attack ranging from 10.004 degrees to 34.858 degrees. The Reynolds number based on the mean aerodynamic chord of the wing was 4.3 x 10 (sup 6). Compared to experiment, the numerical procedure predicted the surface pressures very well at angles of attack in the linear range of the lift. However, computed maximum lift was 5% low. Drag was mainly under predicted. The procedure correctly predicted several well-known trends and features of high-lift flows, such as off-body separation. The two turbulence models yielded significantly different solutions for the repeated case.
Wang, Xiujuan; Qiang, Jin; Collett, Timothy S.; Shi, Hesheng; Yang, Shengxiong; Yan, Chengzhi; Li, Yuanping; Wang, Zhenzhen; Chen, Duanxin
2016-01-01
A new 3D seismic reflection data volume acquired in 2012 has allowed for the detailed mapping and characterization of gas hydrate distribution in the Pearl River Mouth Basin in the South China Sea. Previous studies of core and logging data showed that gas hydrate occurrence at high concentrations is controlled by the presence of relatively coarse-grained sediment and the upward migration of thermogenic gas from the deeper sediment section into the overlying gas hydrate stability zone (BGHSZ); however, the spatial distribution of the gas hydrate remains poorly defined. We used a constrained sparse spike inversion technique to generate acoustic-impedance images of the hydrate-bearing sedimentary section from the newly acquired 3D seismic data volume. High-amplitude reflections just above the bottom-simulating reflectors (BSRs) were interpreted to be associated with the accumulation of gas hydrate with elevated saturations. Enhanced seismic reflections below the BSRs were interpreted to indicate the presence of free gas. The base of the BGHSZ was established using the occurrence of BSRs. In areas absent of well-developed BSRs, the BGHSZ was calculated from a model using the inverted P-wave velocity and subsurface temperature data. Seismic attributes were also extracted along the BGHSZ that indicate variations reservoir properties and inferred hydrocarbon accumulations at each site. Gas hydrate saturations estimated from the inversion of acoustic impedance of conventional 3D seismic data, along with well-log-derived rock-physics models were also used to estimate gas hydrate saturations. Our analysis determined that the gas hydrate petroleum system varies significantly across the Pearl River Mouth Basin and that variability in sedimentary properties as a product of depositional processes and the upward migration of gas from deeper thermogenic sources control the distribution of gas hydrates in this basin.
Linearly Scaling 3D Fragment Method for Large-Scale Electronic Structure Calculations
Wang, Lin-Wang; Lee, Byounghak; Shan, Hongzhang; Zhao, Zhengji; Meza, Juan; Strohmaier, Erich; Bailey, David H.
2008-07-01
We present a new linearly scaling three-dimensional fragment (LS3DF) method for large scale ab initio electronic structure calculations. LS3DF is based on a divide-and-conquer approach, which incorporates a novel patching scheme that effectively cancels out the artificial boundary effects due to the subdivision of the system. As a consequence, the LS3DF program yields essentially the same results as direct density functional theory (DFT) calculations. The fragments of the LS3DF algorithm can be calculated separately with different groups of processors. This leads to almost perfect parallelization on tens of thousands of processors. After code optimization, we were able to achieve 35.1 Tflop/s, which is 39percent of the theoretical speed on 17,280 Cray XT4 processor cores. Our 13,824-atom ZnTeO alloy calculation runs 400 times faster than a direct DFTcalculation, even presuming that the direct DFT calculation can scale well up to 17,280 processor cores. These results demonstrate the applicability of the LS3DF method to material simulations, the advantage of using linearly scaling algorithms over conventional O(N3) methods, and the potential for petascale computation using the LS3DF method.
3D Distribution of the Coronal Electron Density and its Evolution with Solar Cycle
NASA Astrophysics Data System (ADS)
Wang, Tongjiang; Reginald, Nelson Leslie; Davila, Joseph M.; St. Cyr, Orville Chris
2016-05-01
The variability of the solar white-light corona and its connection to the solar activity has been studied for more than a half century. It is widely accepted that the temporal variation of the total radiance of the K-corona follows the solar cycle pattern (e.g., correlated with sunspot number). However, the origin of this variation and its relationships with regard to coronal mass ejections and the solar wind are yet to be clearly understood. We know that the COR1-A and -B instruments onboard the STEREO spacecraft have continued to perform high-cadence (5 min) polarized brightness measurements from two different vantage points over a long period of time that encompasses the solar minimum of Solar Cycle 23 to the solar maximum of Solar Cycle 24. This extended period of polarized brightness measurements can now be used to reconstruct 3D electron density distributions of the corona between the heliocentric heights of 1.5-4.0 solar radii. In this study we have constructed the 3D coronal density models for 100 Carrington rotations (CRs) from 2007 to 2014 using the spherically symmetric inversion (SSI) method. The validity of these 3D density models is verified by comparing with similar 3D density models created by other means such as tomography, MHD modeling, and 2D density distributions inverted from the polarized brightness images from LASCO/C2 instrument onboard the SOHO spacecraft. When examining the causes for the temporal variation of the global electron content we find that its increase from the solar minimum to maximum depends on changes to both the total area and mean density of coronal streamers. We also find that the global and hemispheric electron contents show quasi-periodic variations with a period of 8-9 CRs during the ascending and maximum phases of Solar Cycle 24 through wavelet analysis. In addition, we also explore any obvious relationships between temporal variation of the global electron content with the photospheric magnetic flux, total mass of
NASA Astrophysics Data System (ADS)
Feng, L.; Inhester, B.; Wei, Y.; Guo, J.; Plowman, J.; West, M. J.
2016-12-01
We Follow the 3D evolution of a coronal shock from its birth in the AIA field of view (FOV) to its propagation in interplanetary space till Mars. The shock structure is identified using the center-median filtering method which is applied to EUV observations including SDO/AIA and Proba2/SWAP. Then 3D shock morphology is reconstructed with the mask-fitting method (Feng et al. 2012,2013) from the triple-view observations at Earth, STEREO A and B in the FOV from EUV through coronagraph to heliospheric images. The mask-fitting method allows us to obtain a better shape of the 3D shock and calculate the anisotropy of shock evolution. The shock signals were later recorded in in-situ data by Messenger (0.39 AU), Venus Express (0.72 AU), WIND/ACE (1AU), STEREO B (1.03AU), Mars Science Laboratory (1.20AU), and Mars Express(1.52AU). These spacecraft were located at different distances and different longitudes relative to the Sun. Therefore, the corresponding in-situ data can provide further constraint on the shock dynamics along different directions on one hand, on the other hand reveal longitudinal distributions of SEPs in a wide angle of about 120 degrees. We also run ENLIL simulations based on the derived 3D shock morphology and dynamics. The magnetic field connectivity to aforementioned spacecraft and the obtained shock characteristics (e.g., shock geometry, speed, Alfven Mach number, etc.) at cobpoint can help with the understanding of the SEP properties (e.g., energy spectra) measured at different longitudes.
A new approach to calculate Plant Area Density (PAD) using 3D ground-based lidar
NASA Astrophysics Data System (ADS)
Taheriazad, Leila; Moghadas, Hamid; Sanchez-Azofeifa, Arturo
2016-10-01
This paper presents a novel algorithm for calculation of plant area density based on surface and volume convex hull which is applied to each horizontal cut of a point cloud data. This method can be used as an alternative to conventional voxelization approaches to improve accuracy and computation efficiency. The terrestrial data was collected from a boreal forest at Peace River, Alberta, Canada during summer and fall in 2014. This technique can be applied to an arbitrary point cloud data to calculate all other metrics of forests including plant area index, leaf area density, and also leaf area index.
NASA Astrophysics Data System (ADS)
Homer, Rachel M.; Law, David W.; Molyneaux, Thomas C. K.
2015-07-01
In previous studies, a 1-D numerical predictive tool to simulate the salt induced corrosion of port assets in Australia has been developed into a 2-D and 3-D model based on current predictive probabilistic models. These studies use a probability distribution function based on the mean and standard deviation of the parameters for a structure incorporating surface chloride concentration, diffusion coefficient and cover. In this paper, this previous work is extended through an investigation of the distribution of actual cover by specified cover, element type and method of construction. Significant differences are found for the measured cover within structures, by method of construction, element type and specified cover. The data are not normally distributed and extreme values, usually low, are found in a number of locations. Elements cast insitu are less likely to meet the specified cover and the measured cover is more dispersed than those in elements which are precast. Individual probability distribution functions are available and are tested against the original function. Methods of combining results so that one distribution is available for a structure are formulated and evaluated. The ability to utilise the model for structures where no measurement have been taken is achieved by transposing results based on the specified cover.
3D iterative full and half scan reconstruction in CT architectures with distributed sources
NASA Astrophysics Data System (ADS)
Iatrou, M.; De Man, B.; Beque, D.; Yin, Z.; Khare, K.; Benson, T. M.
2008-03-01
In 3 rd generation CT systems projection data, generated by X-rays emitted from a single source and passing through the imaged object, are acquired by a single detector covering the entire field of view (FOV). Novel CT system architectures employing distributed sources [1,2] could extend the axial coverage, while removing cone-beam artifacts and improving spatial resolution and dose. The sources can be distributed in plane and/or in the longitudinal direction. We investigate statistical iterative reconstruction of multi-axial data, acquired with simulated CT systems with multiple sources distributed along the in-plane and longitudinal directions. The current study explores the feasibility of 3D iterative Full and Half Scan reconstruction methods for CT systems with two different architectures. In the first architecture the sources are distributed in the longitudinal direction, and in the second architecture the sources are distributed both longitudinally and trans-axially. We used Penalized Weighted Least Squares Transmission Reconstruction (PWLSTR) and incorporated a projector-backprojector model matching the simulated architectures. The proposed approaches minimize artifacts related to the proposed geometries. The reconstructed images show that the investigated architectures can achieve good image quality for very large coverage without severe cone-beam artifacts.
Elias, P Q; Jarrige, J; Cucchetti, E; Cannat, F; Packan, D
2017-09-01
Measuring the full ion velocity distribution function (IVDF) by non-intrusive techniques can improve our understanding of the ionization processes and beam dynamics at work in electric thrusters. In this paper, a Laser-Induced Fluorescence (LIF) tomographic reconstruction technique is applied to the measurement of the IVDF in the plume of a miniature Hall effect thruster. A setup is developed to move the laser axis along two rotation axes around the measurement volume. The fluorescence spectra taken from different viewing angles are combined using a tomographic reconstruction algorithm to build the complete 3D (in phase space) time-averaged distribution function. For the first time, this technique is used in the plume of a miniature Hall effect thruster to measure the full distribution function of the xenon ions. Two examples of reconstructions are provided, in front of the thruster nose-cone and in front of the anode channel. The reconstruction reveals the features of the ion beam, in particular on the thruster axis where a toroidal distribution function is observed. These findings are consistent with the thruster shape and operation. This technique, which can be used with other LIF schemes, could be helpful in revealing the details of the ion production regions and the beam dynamics. Using a more powerful laser source, the current implementation of the technique could be improved to reduce the measurement time and also to reconstruct the temporal evolution of the distribution function.
NASA Astrophysics Data System (ADS)
Gupta, N.; Callaghan, S.; Graves, R.; Mehta, G.; Zhao, L.; Deelman, E.; Jordan, T. H.; Kesselman, C.; Okaya, D.; Cui, Y.; Field, E.; Gupta, V.; Vahi, K.; Maechling, P. J.
2006-12-01
Researchers from the SCEC Community Modeling Environment (SCEC/CME) project are utilizing the CyberShake computational platform and a distributed high performance computing environment that includes USC High Performance Computer Center and the NSF TeraGrid facilities to calculate physics-based probabilistic seismic hazard curves for several sites in the Southern California area. Traditionally, probabilistic seismic hazard analysis (PSHA) is conducted using intensity measure relationships based on empirical attenuation relationships. However, a more physics-based approach using waveform modeling could lead to significant improvements in seismic hazard analysis. Members of the SCEC/CME Project have integrated leading-edge PSHA software tools, SCEC-developed geophysical models, validated anelastic wave modeling software, and state-of-the-art computational technologies on the TeraGrid to calculate probabilistic seismic hazard curves using 3D waveform-based modeling. The CyberShake calculations for a single probablistic seismic hazard curve require tens of thousands of CPU hours and multiple terabytes of disk storage. The CyberShake workflows are run on high performance computing systems including multiple TeraGrid sites (currently SDSC and NCSA), and the USC Center for High Performance Computing and Communications. To manage the extensive job scheduling and data requirements, CyberShake utilizes a grid-based scientific workflow system based on the Virtual Data System (VDS), the Pegasus meta-scheduler system, and the Globus toolkit. Probabilistic seismic hazard curves for spectral acceleration at 3.0 seconds have been produced for eleven sites in the Southern California region, including rock and basin sites. At low ground motion levels, there is little difference between the CyberShake and attenuation relationship curves. At higher ground motion (lower probability) levels, the curves are similar for some sites (downtown LA, I-5/SR-14 interchange) but different for
Boggula, Ramesh; Jahnke, Lennart; Wertz, Hansjoerg; Lohr, Frank; Wenz, Frederik
2011-11-15
Purpose: Fast and reliable comprehensive quality assurance tools are required to validate the safety and accuracy of complex intensity-modulated radiotherapy (IMRT) plans for prostate treatment. In this study, we evaluated the performance of the COMPASS system for both off-line and potential online procedures for the verification of IMRT treatment plans. Methods and Materials: COMPASS has a dedicated beam model and dose engine, it can reconstruct three-dimensional dose distributions on the patient anatomy based on measured fluences using either the MatriXX two-dimensional (2D) array (offline) or a 2D transmission detector (T2D) (online). For benchmarking the COMPASS dose calculation, various dose-volume indices were compared against Monte Carlo-calculated dose distributions for five prostate patient treatment plans. Gamma index evaluation and absolute point dose measurements were also performed in an inhomogeneous pelvis phantom using extended dose range films and ion chamber for five additional treatment plans. Results: MatriXX-based dose reconstruction showed excellent agreement with the ion chamber (<0.5%, except for one treatment plan, which showed 1.5%), film ({approx}100% pixels passing gamma criteria 3%/3 mm) and mean dose-volume indices (<2%). The T2D based dose reconstruction showed good agreement as well with ion chamber (<2%), film ({approx}99% pixels passing gamma criteria 3%/3 mm), and mean dose-volume indices (<5.5%). Conclusion: The COMPASS system qualifies for routine prostate IMRT pretreatment verification with the MatriXX detector and has the potential for on-line verification of treatment delivery using T2D.
NASA Astrophysics Data System (ADS)
Krabbenhoeft, A.; Papenberg, C. A.; Klaeschen, D.; Bialas, J.
2016-12-01
The goal of this study is to image the sub-seafloor structure beneath the Sevastopol mud volcano (SMV), Sorokin Trough, SE of the Crimean peninsula, Black Sea. The focus lies on structures of/within the feeder channel, the distribution of gas and gas hydrates, and their relation to fluid migration zones in sediments. This study concentrates on a 3D high resolution seismic grid (7 km x 2.5 km) recorded with 13 ocean bottom stations (OBS). The 3D nature of the experiment results from the geometry of 68 densely spaced (25/50 m) profiles, as well as the cubical configuration of the densely spaced receivers on the seafloor ( 300 m station spacing). The seismic profiles are typically longer than 6 km which results in large offsets for the reflections of the OBS. This enables the study of the seismic velocities of the sub-seafloor sediments and additionally large offset incident analysis.The 3D Kirchhoff mirror image time migration, applied to all OBS sections including all shots from all profiles, leads to a spatial image of the sub-seafloor. Here, the migration was applied with the velocity distribution of 1.49 km/s in the water column, 1.5 km/s below the seafloor (bsf) increasing to 2 km/s for the deeper sediments at 2 s bsf. Acoustic blanking occurs beneath the south-easterly located OBS and is associated with the feeder channel of the mud volcano. There, gas from depth can vertically migrate to the seafloor and on its way to the surface horizontally distribute patchily within sediment layers. High amplitude reflections are not observed as continuous reflections, but in a patchy distribution. They are associated with accumulations of gas. Also structures exist within the feeder channel of the SMV.3D mirror imaging proves to be a good tool to seismically image structures compared with 2D streamer seismics, especially steep dipping reflectors and structures which are otherwise obscured by signal scattering, i.e structures associated with fluid migration paths.
Dose distribution and mapping with 3D imaging presentation in intraoral and panoramic examinations
NASA Astrophysics Data System (ADS)
Chen, Hsiu-Ling; Huang, Yung-Hui; Wu, Tung-Hsin; Wang, Shih-Yuan; Lee, Jason J. S.
2011-10-01
In current medical imaging applications, high quality images not only provide more diagnostic value for anatomic delineation but also offer functional information for treatment direction. However, this approach would potentially subscribe higher radiation dose in dental radiographies, which has been putatively associated with low-birth-weight during pregnancy, which affects the hypothalamus-pituitary-thyroid axis or thereby directly affects the reproductive organs. The aim of this study was to apply the high resolution 3-D image mapping technique to evaluate radiation doses from the following aspects: (1) verifying operating parameters of dental X-ray units, (2) measuring the leakage radiations and (3) mapping dose with 3-D radiographic imaging to evaluate dose distribution in head and neck regions. From the study results, we found that (1) leakage radiation from X-ray units was about 21.31±15.24 mR/h (<100 mR/h), (2) error of actual tube voltage for 60 kVp setting was from 0.2% to 6.5%, with an average of 2.5% (<7%) and (3) the error of exposure time for a 0.5-1.5 s setting was within 0.7-8.5%, with an average of 7.3% (<10%) error as well. Our 3-D dose mapping demonstrated that dose values were relatively lower in soft tissues and higher in bone surfaces compared with other investigations. Multiple causes could contribute to these variations, including irradiation geometry, image equipment and type of technique applied, etc. From the results, we also observed that larger accumulated doses were presented in certain critical organs, such as salivary gland, thyroid gland and bone marrow. Potential biological affects associated with these findings warrant further investigation.
Feasibility of a Multigroup Deterministic Solution Method for 3D Radiotherapy Dose Calculations
Vassiliev, Oleg N.; Wareing, Todd A.; Davis, Ian M.; McGhee, John; Barnett, Douglas; Horton, John L.; Gifford, Kent; Failla, Gregory; Titt, Uwe; Mourtada, Firas
2008-01-01
Purpose To investigate the potential of a novel deterministic solver, Attila, for external photon beam radiotherapy dose calculations. Methods and Materials Two hypothetical cases for prostate and head and neck cancer photon beam treatment plans were calculated using Attila and EGSnrc Monte Carlo simulations. Open beams were modeled as isotropic photon point sources collimated to specified field sizes (100 cm SSD). The sources had a realistic energy spectrum calculated by Monte Carlo for a Varian Clinac 2100 operated in a 6MV photon mode. The Attila computational grids consisted of 106,000 elements, or 424,000 spatial degrees of freedom, for the prostate case, and 123,000 tetrahedral elements, or 492,000 spatial degrees of freedom, for the head and neck cases. Results For both cases, results demonstrate excellent agreement between Attila and EGSnrc in all areas, including the build-up regions, near heterogeneities, and at the beam penumbra. Dose agreement for 99% of the voxels was within 3% (relative point-wise difference) or 3mm distance-to-agreement criterion. Localized differences between the Attila and EGSnrc results were observed at bone and soft tissue interfaces, and are attributable to the effect of voxel material homogenization in calculating dose-to-medium in EGSnrc. For both cases, Attila calculation times were under 20 CPU minutes on a single 2.2 GHz AMD Opteron processor. Conclusions The methods in Attila have the potential to be the basis for an efficient dose engine for patient specific treatment planning, providing accuracy similar to that obtained by Monte Carlo. PMID:18722273
None, None
2015-09-28
Coulomb interaction between charged particles inside a bunch is one of the most importance collective effects in beam dynamics, becoming even more significant as the energy of the particle beam is lowered to accommodate analytical and low-Z material imaging purposes such as in the time resolved Ultrafast Electron Microscope (UEM) development currently underway at Michigan State University. In addition, space charge effects are the key limiting factor in the development of ultrafast atomic resolution electron imaging and diffraction technologies and are also correlated with an irreversible growth in rms beam emittance due to fluctuating components of the nonlinear electron dynamics.more » In the short pulse regime used in the UEM, space charge effects also lead to virtual cathode formation in which the negative charge of the electrons emitted at earlier times, combined with the attractive surface field, hinders further emission of particles and causes a degradation of the pulse properties. Space charge and virtual cathode effects and their remediation are core issues for the development of the next generation of high-brightness UEMs. Since the analytical models are only applicable for special cases, numerical simulations, in addition to experiments, are usually necessary to accurately understand the space charge effect. In this paper we will introduce a grid-free differential algebra based multiple level fast multipole algorithm, which calculates the 3D space charge field for n charged particles in arbitrary distribution with an efficiency of O(n), and the implementation of the algorithm to a simulation code for space charge dominated photoemission processes.« less
None, None
2015-09-28
Coulomb interaction between charged particles inside a bunch is one of the most importance collective effects in beam dynamics, becoming even more significant as the energy of the particle beam is lowered to accommodate analytical and low-Z material imaging purposes such as in the time resolved Ultrafast Electron Microscope (UEM) development currently underway at Michigan State University. In addition, space charge effects are the key limiting factor in the development of ultrafast atomic resolution electron imaging and diffraction technologies and are also correlated with an irreversible growth in rms beam emittance due to fluctuating components of the nonlinear electron dynamics. In the short pulse regime used in the UEM, space charge effects also lead to virtual cathode formation in which the negative charge of the electrons emitted at earlier times, combined with the attractive surface field, hinders further emission of particles and causes a degradation of the pulse properties. Space charge and virtual cathode effects and their remediation are core issues for the development of the next generation of high-brightness UEMs. Since the analytical models are only applicable for special cases, numerical simulations, in addition to experiments, are usually necessary to accurately understand the space charge effect. In this paper we will introduce a grid-free differential algebra based multiple level fast multipole algorithm, which calculates the 3D space charge field for n charged particles in arbitrary distribution with an efficiency of O(n), and the implementation of the algorithm to a simulation code for space charge dominated photoemission processes.
NASA Astrophysics Data System (ADS)
Hartman, H.; Engström, L.; Lundberg, H.; Nilsson, H.; Quinet, P.; Fivet, V.; Palmeri, P.; Malcheva, G.; Blagoev, K.
2017-04-01
Aims: This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions from 3d84d levels of astrophysical interest in singly ionized nickel. Methods: Radiative lifetimes of seven high-lying levels of even parity in Ni II (98 400-100 600 cm-1) have been measured using the time-resolved laser-induced fluorescence method. Two-step photon excitation of ions produced by laser ablation has been utilized to populate the levels. Theoretical calculations of the radiative lifetimes of the measured levels and transition probabilities from these levels are reported. The calculations have been performed using a pseudo-relativistic Hartree-Fock method, taking into account core polarization effects. Results: A new set of transition probabilities and oscillator strengths has been deduced for 477 Ni II transitions of astrophysical interest in the spectral range 194-520 nm depopulating even parity 3d84d levels. The new calculated gf-values are, on the average, about 20% higher than a previous calculation and yield lifetimes within 5% of the experimental values.
Distributed snow and rock temperature modelling in steep rock walls using Alpine3D
NASA Astrophysics Data System (ADS)
Haberkorn, Anna; Wever, Nander; Hoelzle, Martin; Phillips, Marcia; Kenner, Robert; Bavay, Mathias; Lehning, Michael
2017-02-01
In this study we modelled the influence of the spatially and temporally heterogeneous snow cover on the surface energy balance and thus on rock temperatures in two rugged, steep rock walls on the Gemsstock ridge in the central Swiss Alps. The heterogeneous snow depth distribution in the rock walls was introduced to the distributed, process-based energy balance model Alpine3D with a precipitation scaling method based on snow depth data measured by terrestrial laser scanning. The influence of the snow cover on rock temperatures was investigated by comparing a snow-covered model scenario (precipitation input provided by precipitation scaling) with a snow-free (zero precipitation input) one. Model uncertainties are discussed and evaluated at both the point and spatial scales against 22 near-surface rock temperature measurements and high-resolution snow depth data from winter terrestrial laser scans.In the rough rock walls, the heterogeneously distributed snow cover was moderately well reproduced by Alpine3D with mean absolute errors ranging between 0.31 and 0.81 m. However, snow cover duration was reproduced well and, consequently, near-surface rock temperatures were modelled convincingly. Uncertainties in rock temperature modelling were found to be around 1.6 °C. Errors in snow cover modelling and hence in rock temperature simulations are explained by inadequate snow settlement due to linear precipitation scaling, missing lateral heat fluxes in the rock, and by errors caused by interpolation of shortwave radiation, wind and air temperature into the rock walls.Mean annual near-surface rock temperature increases were both measured and modelled in the steep rock walls as a consequence of a thick, long-lasting snow cover. Rock temperatures were 1.3-2.5 °C higher in the shaded and sunny rock walls, while comparing snow-covered to snow-free simulations. This helps to assess the potential error made in ground temperature modelling when neglecting snow in steep bedrock.
Local ISM 3D Distribution and Soft X-ray Background Inferences for Nearby Hot Gas
NASA Technical Reports Server (NTRS)
Puspitarini, L.; Lallement, R.; Snowden, Steven L.; Vergely, J.-L.; Snowden, S.
2014-01-01
Three-dimensional (3D) interstellar medium (ISM) maps can be used to locate not only interstellar (IS) clouds, but also IS bubbles between the clouds that are blown by stellar winds and supernovae, and are filled by hot gas. To demonstrate this, and to derive a clearer picture of the local ISM, we compare our recent 3D IS dust distribution maps to the ROSAT diffuse Xray background maps after removal of heliospheric emission. In the Galactic plane, there is a good correspondence between the locations and extents of the mapped nearby cavities and the soft (0.25 keV) background emission distribution, showing that most of these nearby cavities contribute to this soft X-ray emission. Assuming a constant dust to gas ratio and homogeneous 106 K hot gas filling the cavities, we modeled in a simple way the 0.25 keV surface brightness along the Galactic plane as seen from the Sun, taking into account the absorption by the mapped clouds. The data-model comparison favors the existence of hot gas in the solar neighborhood, the so-called Local Bubble (LB). The inferred mean pressure in the local cavities is found to be approx.9,400/cu cm K, in agreement with previous studies, providing a validation test for the method. On the other hand, the model overestimates the emission from the huge cavities located in the third quadrant. Using CaII absorption data, we show that the dust to CaII ratio is very small in those regions, implying the presence of a large quantity of lower temperature (non-X-ray emitting) ionized gas and as a consequence a reduction of the volume filled by hot gas, explaining at least part of the discrepancy. In the meridian plane, the two main brightness enhancements coincide well with the LB's most elongated parts and chimneys connecting the LB to the halo, but no particular nearby cavity is found towards the enhancement in the direction of the bright North Polar Spur (NPS) at high latitude. We searched in the 3D maps for the source regions of the higher energy
Linear Scaling 3D Fragment Method for Large-Scale ElectronicStructure Calculations
Wang, Lin-Wang; Zhao, Zhengji; Meza, Juan
2006-10-16
We present a linear scaling 3 dimensional fragment (LS3DF)method that uses a novel decomposition and patching scheme to do abinitio density functional theory (DFT) calculations for large systems.This method cancels out the artificial boundary effects that arise fromthe spatial decomposition. As a result, the LS3DF results are essentiallythe same as the original full-system DFT results with errors smaller thanthe errors introduced by other sources of numerical approximations. Inaddition, the resulting computational times are thousands of timessmaller than conventional DFT methods, making calculations with 100,000atom systems possible. The LS3DF method is applicable to insulator andsemiconductor systems, which covers a current gap in the DOE's materialsscience code portfolio for large-scale ab initio simulations.
3D calculations of the Superconducting Super Collider (SSC) 3 Tesla magnet
Lari, R.J.
1984-01-01
A 20 TeV Superconducting Super Collider (SSC) proton accelerator is being proposed by the High Energy Physics Community. One proposal would consist of a ring of magnets 164 km in circumference with a field strength of 3 Tesla and would cost 2.7 billion dollars. The magnet consists of stacked steel laminations with superconducting coils. The desired field uniformity is obtained for all fields from 0.2 to 3 Tesla by using three (or more) different pole shapes. These three different laminations are stacked in the order 1-2-3-1-2-3-... creating a truly three dimensional geometry. A three laminated stack 1-2-3 with periodic boundary conditions at 1 and 3 was assigned about 5000 finite elements per lamination and solved using the computer program TOSCA. To check the TOSCA results, the field of each of the three different shaped laminations was calculated separately using periodic boundary conditions and compared to the two dimensional field calculations using TRIM. This was done for a constant permeability of 2000 and using the B-H table for fully annealed 1010 steel. The difference of the field calculations in the region of interest was always less than +-.2%
NASA Astrophysics Data System (ADS)
Bocanegra, Humberto; Gorumlu, Seder; Aksak, Burak; Castillo, Luciano; Sheng, Jian
2015-11-01
Understanding how fluid flow interacts with micro-textured surfaces is crucial for a broad range of key biological processes and engineering applications including particle dispersion, pathogenic infections, and drag manipulation by surface topology. Existing methods, such as μPIV, suffers from low spatial resolution and fail to track tracer particle motion very close to a rough surface and within roughness elements. In this paper, we present a technique that combines high speed digital holographic microscopy (DHM) with a correlation based de-noising algorithm to overcome the optical interference generated by surface roughness and to capture a large number of 3D particle trajectories. It allows us to obtain a 3D velocity field with an uncertainty of 0.01% and 2D wall shear stress distribution at the resolution of ~ 65 μPa. Applying the technique to a microfluidics with a surface textured by microfibers, we find that the flow is three-dimensional and complex. While the microfibers affect the velocity flow field locally, their presence is felt globally in terms of wall shear stresses. The study of effect of microfiber patterns and flow characteristics on skin frictions are ongoing and will be reported.
Intensity distribution angular shaping - Practical approach for 3D optical beamforming
NASA Astrophysics Data System (ADS)
Wojtanowski, Jacek; Traczyk, Maciej; Zygmunt, Marek; Mierczyk, Zygmunt; Knysak, Piotr; Drozd, Tadeusz
2014-12-01
We present approach of optical design which enables to obtain aspheric lens shape optimized for providing the specific light power density distribution in space. Proposed method is based on the evaluation of corresponding angular intensity distribution which can be obtained by the decomposition of the desired spatial distribution into virtual light cones set and collapsing it to the equivalent angular fingerprint. Rigorous formulas have been derived to relate refractive aspheric shape and the corresponding intensity distribution which is used for lens optimization. Algorithms of modeling and optimization were implemented in Matlab© and the calculated designs were successfully tested in Zemax environment.
Calculations of separated 3-D flows with a pressure-staggered Navier-Stokes equations solver
NASA Technical Reports Server (NTRS)
Kim, S.-W.
1991-01-01
A Navier-Stokes equations solver based on a pressure correction method with a pressure-staggered mesh and calculations of separated three-dimensional flows are presented. It is shown that the velocity pressure decoupling, which occurs when various pressure correction algorithms are used for pressure-staggered meshes, is caused by the ill-conditioned discrete pressure correction equation. The use of a partial differential equation for the incremental pressure eliminates the velocity pressure decoupling mechanism by itself and yields accurate numerical results. Example flows considered are a three-dimensional lid driven cavity flow and a laminar flow through a 90 degree bend square duct. For the lid driven cavity flow, the present numerical results compare more favorably with the measured data than those obtained using a formally third order accurate quadratic upwind interpolation scheme. For the curved duct flow, the present numerical method yields a grid independent solution with a very small number of grid points. The calculated velocity profiles are in good agreement with the measured data.
Aorta cross-section calculation and 3D visualization from CT or MRT data using VRML
NASA Astrophysics Data System (ADS)
Grabner, Guenther; Modritsch, Robert; Stiegmaier, Wolfgang; Grasser, Simon; Klinger, Thomas
2005-04-01
Quantification of vessel diameters of artherosclerotic or congenital stenosis is very important for the diagnosis of vascular diseases. The aorta extraction and cross-section calculation is a software-based application that offers a three-dimensional, platform-independent, colorized visualization of the extracted aorta with augmented reality information of MRT or CT datasets. This project is based on different types of specialized image processing algorithms, dynamical particle filtering and complex mathematical equations. From this three-dimensional model a calculation of minimal cross sections is performed. In user specified distances, the aorta is cut in differently defined directions which are created through vectors with varying length. The extracted aorta and the derived minimal cross-sections are then rendered with the marching cube algorithm and represented together in a three-dimensional virtual reality with a very high degree of immersion. The aim of this study was to develop an imaging software that delivers cardiologists the possibility of (i) furnishing fast vascular diagnosis, (ii) getting precise diameter information, (iii) being able to process exact, local stenosis detection (iv) having permanent data storing and easy access to former datasets, and (v) reliable documentation of results in form of tables and graphical printouts.
The distribution of 3D superconductivity near the second critical field
NASA Astrophysics Data System (ADS)
Kachmar, Ayman; Nasrallah, Marwa
2016-09-01
We study the minimizers of the Ginzburg-Landau energy functional with a uniform magnetic field in a three dimensional bounded domain. The functional depends on two positive parameters, the Ginzburg-Landau parameter and the intensity of the applied magnetic field, and acts on complex-valued functions and vector fields. We establish a formula for the distribution of the L 2-norm of the minimizing complex-valued function (order parameter). The formula is valid in the regime where the Ginzburg-Landau parameter is large and the applied magnetic field is close to and strictly below the second critical field—the threshold value corresponding to the transition from the superconducting to the normal phase in the bulk of the sample. Earlier results are valid in 2D domains and for the L 4-norm in 3D domains.
The 3-D Euler and Navier-Stokes calculations for aircraft components
NASA Technical Reports Server (NTRS)
Vatsa, Veer N.; Wedan, Bruce W.; Turkel, Eli
1989-01-01
An explicit multistage Runge-Kutta type of time-stepping scheme is used for solving transonic flow past a transport type wing/fuselage configuration. Solutions for both Euler and Navier-Stokes equations are obtained for quantitative assessment of boundary layer interaction effects. The viscous solutions are obtained on both a medium resolution grid of approximately 270,000 points and a find grid of 460,000 points to assess the effects of grid density on the solution. Computed pressure distributions are compared with the experimental data.
Inverse modeling of InSAR and ground leveling data for 3D volumetric strain distribution
NASA Astrophysics Data System (ADS)
Gallardo, L. A.; Glowacka, E.; Sarychikhina, O.
2015-12-01
Wide availability of modern Interferometric Synthetic aperture Radar (InSAR) data have made possible the extensive observation of differential surface displacements and are becoming an efficient tool for the detailed monitoring of terrain subsidence associated to reservoir dynamics, volcanic deformation and active tectonism. Unfortunately, this increasing popularity has not been matched by the availability of automated codes to estimate underground deformation, since many of them still rely on trial-error subsurface model building strategies. We posit that an efficient algorithm for the volumetric modeling of differential surface displacements should match the availability of current leveling and InSAR data and have developed an algorithm for the joint inversion of ground leveling and dInSAR data in 3D. We assume the ground displacements are originated by a stress free-volume strain distribution in a homogeneous elastic media and determined the displacement field associated to an ensemble of rectangular prisms. This formulation is then used to develop a 3D conjugate gradient inversion code that searches for the three-dimensional distribution of the volumetric strains that predict InSAR and leveling surface displacements simultaneously. The algorithm is regularized applying discontinuos first and zero order Thikonov constraints. For efficiency, the resulting computational code takes advantage of the resulting convolution integral associated to the deformation field and some basic tools for multithreading parallelization. We extensively test our algorithm on leveling and InSAR test and field data of the Northwest of Mexico and compare to some feasible geological scenarios of underground deformation.
3D Self-Potential Inversion for Monitoring DNAPL Contaminant Distributions
NASA Astrophysics Data System (ADS)
Minsley, B. J.; Sogade, J.; Vichabian, Y.; Morgan, F. D.
2005-05-01
Self-potential (SP) data are collected over an area known to be contaminated with Dense Non-Aqueous Phase Liquids (DNAPLs) at the Savannah River Site in South Carolina. The field experiment consists of approximately 100 SP measurements on a surface grid and in four boreholes, and is repeated after one year. DNAPLs are known to undergo redox reactions during their degradation in the environment, which is often biologically mediated. Self-potential geophysics is employed in this study because of its sensitivity to the in-situ biochemical processes that degrade the contaminants. These reactions provide an electrochemical source that is manifested as an SP signature at the measurement locations remote from the contaminated areas. 3D inversion of the SP data is therefore needed to spatially locate the distribution of sources, which is related to contaminant presence. The inversion incorporates the 3D resistivity structure collected at the same site, and is better constrained in depth by using borehole data and regularization. Ground truth information taken after the first field experiment provides concentration data with depth for several DNAPL species in five boreholes. There is a good correlation between the ground truth data and SP source inversion, though this comparison is limited by several factors: the difference in resolution of the ground truth and inverted data, and the dependence of the redox processes on other constituents that were not measured during the ground truthing, such as oxygen content or microbial presence. Inversion of the second year's dataset provides information on the changes in the contaminant distribution, either due to natural degradation or ongoing remediation.
The ATLAS 3D project - XXIV. The intrinsic shape distribution of early-type galaxies
NASA Astrophysics Data System (ADS)
Weijmans, Anne-Marie; de Zeeuw, P. T.; Emsellem, Eric; Krajnović, Davor; Lablanche, Pierre-Yves; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, Martin; Cappellari, Michele; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; Duc, Pierre-Alain; Khochfar, Sadegh; Kuntschner, Harald; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Verdoes Kleijn, Gijs; Young, Lisa M.
2014-11-01
We use the ATLAS3D sample to perform a study of the intrinsic shapes of early-type galaxies, taking advantage of the available combined photometric and kinematic data. Based on our ellipticity measurements from the Sloan Digital Sky Survey Data Release 7, and additional imaging from the Isaac Newton Telescope, we first invert the shape distribution of fast and slow rotators under the assumption of axisymmetry. The so-obtained intrinsic shape distribution for the fast rotators can be described with a Gaussian with a mean flattening of q = 0.25 and standard deviation σq = 0.14, and an additional tail towards rounder shapes. The slow rotators are much rounder, and are well described with a Gaussian with mean q = 0.63 and σq = 0.09. We then checked that our results were consistent when applying a different and independent method to obtain intrinsic shape distributions, by fitting the observed ellipticity distributions directly using Gaussian parametrizations for the intrinsic axis ratios. Although both fast and slow rotators are identified as early-type galaxies in morphological studies, and in many previous shape studies are therefore grouped together, their shape distributions are significantly different, hinting at different formation scenarios. The intrinsic shape distribution of the fast rotators shows similarities with the spiral galaxy population. Including the observed kinematic misalignment in our intrinsic shape study shows that the fast rotators are predominantly axisymmetric, with only very little room for triaxiality. For the slow rotators though there are very strong indications that they are (mildly) triaxial.
3D field calculation of the GEM prototype magnet and comparison with measurements
Lari, R.J.
1983-10-28
The proposed 4 GeV Electron Microtron (GEM) is designed to fill the existing buildings left vacant by the demise of the Zero Gradient Synchrotron (ZGS) accelerator. One of the six large dipole magnets is shown as well as the first 10 electron orbits. A 3-orbit prototype magnet has been built. The stepped edge of the magnet is to keep the beam exiting perpendicular to the pole. The end guards that wrap around the main coils are joined together by the 3 shield plates. The auxiliary coils are needed to keep the end guards and shield plates from saturating. A 0.3 cm Purcell filter air gap exists between the pole and the yoke. Can anyone question this being a truly three-dimensional magnetostatic problem. The computer program TOSCA, developed at the Rutherford Appleton Laboratory by the Computing Applications Group, was used to calculate this magnet and the results have been compared with measurements.
Applicability of 3D Monte Carlo simulations for local values calculations in a PWR core
NASA Astrophysics Data System (ADS)
Bernard, Franck; Cochet, Bertrand; Jinaphanh, Alexis; Jacquet, Olivier
2014-06-01
As technical support of the French Nuclear Safety Authority, IRSN has been developing the MORET Monte Carlo code for many years in the framework of criticality safety assessment and is now working to extend its application to reactor physics. For that purpose, beside the validation for criticality safety (more than 2000 benchmarks from the ICSBEP Handbook have been modeled and analyzed), a complementary validation phase for reactor physics has been started, with benchmarks from IRPHEP Handbook and others. In particular, to evaluate the applicability of MORET and other Monte Carlo codes for local flux or power density calculations in large power reactors, it has been decided to contribute to the "Monte Carlo Performance Benchmark" (hosted by OECD/NEA). The aim of this benchmark is to monitor, in forthcoming decades, the performance progress of detailed Monte Carlo full core calculations. More precisely, it measures their advancement towards achieving high statistical accuracy in reasonable computation time for local power at fuel pellet level. A full PWR reactor core is modeled to compute local power densities for more than 6 million fuel regions. This paper presents results obtained at IRSN for this benchmark with MORET and comparisons with MCNP. The number of fuel elements is so large that source convergence as well as statistical convergence issues could cause large errors in local tallies, especially in peripheral zones. Various sampling or tracking methods have been implemented in MORET, and their operational effects on such a complex case have been studied. Beyond convergence issues, to compute local values in so many fuel regions could cause prohibitive slowing down of neutron tracking. To avoid this, energy grid unification and tallies preparation before tracking have been implemented, tested and proved to be successful. In this particular case, IRSN obtained promising results with MORET compared to MCNP, in terms of local power densities, standard
NASA Astrophysics Data System (ADS)
Taha, Uday; Shabeeb, Ahmed; dragonetti, giovanna; Lamaddalena, Nicola; Coppola, Antonio
2016-04-01
This work analyzed the variability of sprinkler irrigation application over a bare soil, both in terms of water application efficiency and uniformity, by integrating and comparing the information on the irrigation depth data (ID), as measured by catch cans, soil water storage in the upper root zone, as measured by TDR probes, and a 3D simulations of water flow in soils. Three irrigation tests were performed at three different pressures (2, 3 and 4 bar). A lateral water redistribution was observed and simulated after each irrigation event by comparing spatial distributions of site-specific water application efficiency (AEs), as well as ratios of site-specific actual water storage increase (SWEs) and irrigation depth (IDs) to the water content before irrigation. Because of soil water redistribution processes, distribution uniformity based on soil storages was systematically higher than the catch can uniformity. The obvious consequence of lateral water redistribution processes was that the soil smoothing action on non-uniformity observed at the surface increased both with depth and over time. At a given depth the uniformity of soil water storages always attained the same value, whatever the pressure considered and the catch can-based uniformity coefficient. It was concluded that, for the case of random distribution of ID, the uniformity of water storages is driven by the soil behavior rather than by the irrigation system.
The Linearly Scaling 3D Fragment Method for Large Scale Electronic Structure Calculations
Zhao, Zhengji; Meza, Juan; Lee, Byounghak; Shan, Hongzhang; Strohmaier, Erich; Bailey, David; Wang, Lin-Wang
2009-06-26
The Linearly Scaling three-dimensional fragment (LS3DF) method is an O(N) ab initio electronic structure method for large-scale nano material simulations. It is a divide-and-conquer approach with a novel patching scheme that effectively cancels out the artificial boundary effects, which exist in all divide-and-conquer schemes. This method has made ab initio simulations of thousand-atom nanosystems feasible in a couple of hours, while retaining essentially the same accuracy as the direct calculation methods. The LS3DF method won the 2008 ACM Gordon Bell Prize for algorithm innovation. Our code has reached 442 Tflop/s running on 147,456 processors on the Cray XT5 (Jaguar) at OLCF, and has been run on 163,840 processors on the Blue Gene/P (Intrepid) at ALCF, and has been applied to a system containing 36,000 atoms. In this paper, we will present the recent parallel performance results of this code, and will apply the method to asymmetric CdSe/CdS core/shell nanorods, which have potential applications in electronic devices and solar cells.
The linearly scaling 3D fragment method for large scale electronic structure calculations
Zhao, Zhengji; Meza, Juan; Lee, Byounghak; Shan, Hongzhang; Strohmaier, Erich; Bailey, David; Wang, Lin-Wang
2009-07-28
The Linearly Scaling three-dimensional fragment (LS3DF) method is an O(N) ab initio electronic structure method for large-scale nano material simulations. It is a divide-and-conquer approach with a novel patching scheme that effectively cancels out the artificial boundary effects, which exist in all divide-and-conquer schemes. This method has made ab initio simulations of thousand-atom nanosystems feasible in a couple of hours, while retaining essentially the same accuracy as the direct calculation methods. The LS3DF method won the 2008 ACM Gordon Bell Prize for algorithm innovation. Our code has reached 442 Tflop/s running on 147,456 processors on the Cray XT5 (Jaguar) at OLCF, and has been run on 163,840 processors on the Blue Gene/P (Intrepid) at ALCF, and has been applied to a system containing 36,000 atoms. In this paper, we will present the recent parallel performance results of this code, and will apply the method to asymmetric CdSe/CdS core/shell nanorods, which have potential applications in electronic devices and solar cells.
The linearly scaling 3D fragment method for large scale electronic structure calculations
NASA Astrophysics Data System (ADS)
Zhao, Zhengji; Meza, Juan; Lee, Byounghak; Shan, Hongzhang; Strohmaier, Erich; Bailey, David; Wang, Lin-Wang
2009-07-01
The linearly scaling three-dimensional fragment (LS3DF) method is an O(N) ab initio electronic structure method for large-scale nano material simulations. It is a divide-and-conquer approach with a novel patching scheme that effectively cancels out the artificial boundary effects, which exist in all divide-and-conquer schemes. This method has made ab initio simulations of thousand-atom nanosystems feasible in a couple of hours, while retaining essentially the same accuracy as the direct calculation methods. The LS3DF method won the 2008 ACM Gordon Bell Prize for algorithm innovation. Our code has reached 442 Tflop/s running on 147,456 processors on the Cray XT5 (Jaguar) at OLCF, and has been run on 163,840 processors on the Blue Gene/P (Intrepid) at ALCF, and has been applied to a system containing 36,000 atoms. In this paper, we will present the recent parallel performance results of this code, and will apply the method to asymmetric CdSe/CdS core/shell nanorods, which have potential applications in electronic devices and solar cells.
The Calculation of the Band Structure in 3D Phononic Crystal with Hexagonal Lattice
NASA Astrophysics Data System (ADS)
Aryadoust, Mahrokh; Salehi, H.
2015-12-01
In this article, the propagation of acoustic waves in the phononic crystals (PCs) of three dimensions with the hexagonal (HEX) lattice is studied theoretically. The PCs are constituted of nickel (Ni) spheres embedded in epoxy. The calculations of the band structure and the density of states are performed using the plane wave expansion (PWE) method in the irreducible part of the Brillouin zone (BZ). In this study, we analyse the dependence of the band structures inside (the complete band gap width) on c/a and filling fraction in the irreducible part of the first BZ. Also, we have analysed the band structure of the ALHA and MLHKM planes. The results show that the maximum width of absolute elastic band gap (AEBG) (0.045) in the irreducible part of the BZ of HEX lattice is formed for c/a=6 and filling fraction equal to 0.01. In addition, the maximum of the first and second AEBG widths are 0.0884 and 0.0474, respectively, in the MLHKM plane, and the maximum of the first and second AEBG widths are 0.0851 and 0.0431, respectively, in the ALHA plane.
NASA Astrophysics Data System (ADS)
Suetin, D. V.; Shein, I. R.; Ivanovskii, A. L.
2009-07-01
First-principles FLAPW-GGA calculations have been performed to predict the structural, electronic, cohesive and magnetic properties for hexagonal tungsten monocarbide ( h-WC) doped with all 3 d metals. The optimized lattice parameters, density of states, cohesive and formation energies have been obtained and analyzed for ternary solid solutions with nominal compositions W 0.875M 0.125C (where M=Sc, Ti…Ni, Cu). In addition, the magnetic properties of these solid solutions have been examined, and magnetization has been established for W 0.875Co 0.125C.
Gan, K F; Ahn, J-W; Park, J-W; Maingi, R; McLean, A G; Gray, T K; Gong, X; Zhang, X D
2013-02-01
The divertor heat flux footprint in tokamaks is often observed to be non-axisymmetric due to intrinsic error fields, applied 3D magnetic fields or during transients such as edge localized modes. Typically, only 1D radial heat flux profiles are analyzed; however, analysis of the full 2D divertor measurements provides opportunities to study the asymmetric nature of the deposited heat flux. To accomplish this an improved 3D Fourier analysis method has been successfully applied in a heat conduction solver (TACO) to determine the 2D heat flux distribution at the lower divertor surface in the National Spherical Torus Experiment (NSTX) tokamak. This advance enables study of helical heat deposition onto the divertor. In order to account for heat transmission through poorly adhered surface layers on the divertor plate, a heat transmission coefficient, defined as the surface layer thermal conductivity divided by the thickness of the layer, was introduced to the solution of heat conduction equation. This coefficient is denoted as α and a range of values were tested in the model to ensure a reliable heat flux calculation until a specific value of α led to the constant total deposited energy in the numerical solution after the end of discharge. A comparison between 1D heat flux profiles from TACO and from a 2D heat flux calculation code, THEODOR, shows good agreement. Advantages of 2D heat flux distribution over the conventional 1D heat flux profile are also discussed, and examples of 2D data analysis in the study of striated heat deposition pattern as well as the toroidal degree of asymmetry of peak heat flux and heat flux width are demonstrated.
Disentangling Fault Scarp Geometry and Slip-Distribution in 3D
NASA Astrophysics Data System (ADS)
Mackenzie, D.; Walker, R. T.
2015-12-01
We present a new and inherently 3D approach to the analysis of fault scarp geometry using high resolution topography. Recent advance in topographic measurement techniques (LiDAR and Structure from Motion) has allowed the extensive measurement of single earthquake scarps and multiple event cumulative scarps to draw conclusions about along-strike slip variation and characteristic slip. Present analysis of the resulting point clouds and digital elevation models is generally achieved by taking vertical or map view profiles of geomorphic markers across the scarp. Profiles are done at numerous locations along strike carefully chosen to avoid regions degraded by erosion/deposition. The resulting slip distributions are almost always extremely variable and "noisy", both for strike-slip and dip-slip faulting scarps and it is often unclear whether this reflects slip variation, noise/erosion, site effects or geometric variation. When observing palaeo-earthquake and even modern event scarps, the full geometry, such as the degree of oblique slip or the fault dip, is often poorly constrained. We first present the results of synthetic tests to demonstrate the introduction of significant apparent noise by simply varying terrain, fault and measurement geometry (slope angle, slope azimuth, fault dip and slip obliquity). Considering fully 3-dimensional marker surfaces (e.g. Planar or conical) we use the variation in apparent offset with terrain and measurement geometry, to constrain the slip geometry in 3D. Combining measurements windowed along strike, we show that determining the slip vector is reduced to a simple linear problem. We conclude that for scarps in regions of significant topography or with oblique slip, our method will give enhanced slip resolution while standard methods will give poor slip resolution. We test our method using a Structure from Motion pointcloud and digital elevation model covering a ~25 km stretch of a thrust fault scarp in the Kazakh Tien Shan.
NASA Astrophysics Data System (ADS)
Zhu, Lin; Gong, Huili; Dai, Zhenxue; Guo, Gaoxuan; Teatini, Pietro
2017-02-01
Alluvial fans are highly heterogeneous in hydraulic properties due to complex depositional processes, which make it difficult to characterize the spatial distribution of the hydraulic conductivity (K). An original methodology is developed to identify the spatial statistical parameters (mean, variance, correlation range) of the hydraulic conductivity in a three-dimensional (3-D) setting by using geological and geophysical data. More specifically, a large number of inexpensive vertical electric soundings are integrated with a facies model developed from borehole lithologic data to simulate the log10(K) continuous distributions in multiple-zone heterogeneous alluvial megafans. The Chaobai River alluvial fan in the Beijing Plain, China, is used as an example to test the proposed approach. Due to the non-stationary property of the K distribution in the alluvial fan, a multiple-zone parameterization approach is applied to analyze the conductivity statistical properties of different hydrofacies in the various zones. The composite variance in each zone is computed to describe the evolution of the conductivity along the flow direction. Consistently with the scales of the sedimentary transport energy, the results show that conductivity variances of fine sand, medium-coarse sand, and gravel decrease from the upper (zone 1) to the lower (zone 3) portion along the flow direction. In zone 1, sediments were moved by higher-energy flooding, which induces poor sorting and larger conductivity variances. The composite variance confirms this feature with statistically different facies from zone 1 to zone 3. The results of this study provide insights to improve our understanding on conductivity heterogeneity and a method for characterizing the spatial distribution of K in alluvial fans.
NASA Astrophysics Data System (ADS)
Bauknecht, Andreas; Steinert, Torsten; Spengler, Carsten; Suck, Gerrit
2013-07-01
Thermoelectric (TE) modules with annular geometry are very attractive for waste heat recovery within the automotive world, especially when integrated as stacks into tubular heat exchangers. The required temperature difference is built up between the coolant, which flows inside an inner tube, and the exhaust gas, which flows around an outer tube. The flow pattern of the exhaust gas can be axial or circumferential, which can lead to higher heat transfer coefficients on the outer surface of the tube. However, this multidimensional construction in combination with a complex flow pattern can lead to a nonuniform heat flux. Additionally, the system experiences a nonuniform temperature distribution which consequently leads to complex conditions regarding the electrical potential. The relevant effects are investigated using a three-dimensional (3-D) numerical model implemented in the computational fluid dynamics (CFD) simulation environment Star-CCM+. The model supports temperature-dependent characteristics of the materials, contact resistances, and parasitic effects in the TE module. Furthermore, it involves techniques to quickly find the exact maximum power point of the TE module with the given boundary conditions. Using the validated model the influence of the nonuniform temperature distribution is investigated with emphasis on the electrical output and TE efficiency.
Enabling 3D-Liver Perfusion Mapping from MR-DCE Imaging Using Distributed Computing.
Leporq, Benjamin; Camarasu-Pop, Sorina; Davila-Serrano, Eduardo E; Pilleul, Frank; Beuf, Olivier
2013-01-01
An MR acquisition protocol and a processing method using distributed computing on the European Grid Infrastructure (EGI) to allow 3D liver perfusion parametric mapping after Magnetic Resonance Dynamic Contrast Enhanced (MR-DCE) imaging are presented. Seven patients (one healthy control and six with chronic liver diseases) were prospectively enrolled after liver biopsy. MR-dynamic acquisition was continuously performed in free-breathing during two minutes after simultaneous intravascular contrast agent (MS-325 blood pool agent) injection. Hepatic capillary system was modeled by a 3-parameters one-compartment pharmacokinetic model. The processing step was parallelized and executed on the EGI. It was modeled and implemented as a grid workflow using the Gwendia language and the MOTEUR workflow engine. Results showed good reproducibility in repeated processing on the grid. The results obtained from the grid were well correlated with ROI-based reference method ran locally on a personal computer. The speed-up range was 71 to 242 with an average value of 126. In conclusion, distributed computing applied to perfusion mapping brings significant speed-up to quantification step to be used for further clinical studies in a research context. Accuracy would be improved with higher image SNR accessible on the latest 3T MR systems available today.
Three-Axis Distributed Fiber Optic Strain Measurement in 3D Woven Composite Structures
NASA Technical Reports Server (NTRS)
Castellucci, Matt; Klute, Sandra; Lally, Evan M.; Froggatt, Mark E.; Lowry, David
2013-01-01
Recent advancements in composite materials technologies have broken further from traditional designs and require advanced instrumentation and analysis capabilities. Success or failure is highly dependent on design analysis and manufacturing processes. By monitoring smart structures throughout manufacturing and service life, residual and operational stresses can be assessed and structural integrity maintained. Composite smart structures can be manufactured by integrating fiber optic sensors into existing composite materials processes such as ply layup, filament winding and three-dimensional weaving. In this work optical fiber was integrated into 3D woven composite parts at a commercial woven products manufacturing facility. The fiber was then used to monitor the structures during a VARTM manufacturing process, and subsequent static and dynamic testing. Low cost telecommunications-grade optical fiber acts as the sensor using a high resolution commercial Optical Frequency Domain Reflectometer (OFDR) system providing distributed strain measurement at spatial resolutions as low as 2mm. Strain measurements using the optical fiber sensors are correlated to resistive strain gage measurements during static structural loading. Keywords: fiber optic, distributed strain sensing, Rayleigh scatter, optical frequency domain reflectometry
Segmentation of 3D holographic images using bivariate jointly distributed region snake
NASA Astrophysics Data System (ADS)
Daneshpanah, Mehdi; Javidi, Bahram
2006-06-01
In this paper, we describe the bivariate jointly distributed region snake method in segmentation of microorganisms in Single Exposure On- Line (SEOL) holographic microscopy images. 3D images of the microorganisms are digitally reconstructed and numerically focused from any arbitrary depth from a single recorded digital hologram without mechanical scanning. Living organisms are non-rigid and they vary in shape and size. Moreover, they often do not exhibit clear edges in digitally reconstructed SEOL holographic images. Thus, conventional segmentation techniques based on the edge map may fail to segment these images. However, SEOL holographic microscopy provides both magnitude and phase information of the sample specimen, which could be helpful in the segmentation process. In this paper, we present a statistical framework based on the joint probability distribution of magnitude and phase information of SEOL holographic microscopy images and maximum likelihood estimation of image probability density function parameters. An optimization criterion is computed by maximizing the likelihood function of the target support hypothesis. In addition, a simple stochastic algorithm has been adapted for carrying out the optimization, while several boosting techniques have been employed to enhance its performance. Finally, the proposed method is applied for segmentation of biological microorganisms in SEOL holographic images and the experimental results are presented.
Travel time calculation in regular 3D grid in local and regional scale using fast marching method
NASA Astrophysics Data System (ADS)
Polkowski, M.
2015-12-01
Local and regional 3D seismic velocity models of crust and sediments are very important for numerous technics like mantle and core tomography, localization of local and regional events and others. Most of those techniques require calculation of wave travel time through the 3D model. This can be achieved using multiple approaches from simple ray tracing to advanced full waveform calculation. In this study simple and efficient implementation of fast marching method is presented. This method provides more information than ray tracing and is much less complicated than methods like full waveform being the perfect compromise. Presented code is written in C++, well commented and is easy to modify for different types of studies. Additionally performance is widely discussed including possibilities of multithreading and massive parallelism like GPU. Source code will be published in 2016 as it is part of the PhD thesis. National Science Centre Poland provided financial support for this work via NCN grant DEC-2011/02/A/ST10/00284.
Florando, J; Rhee, M; Arsenlis, A; LeBlanc, M; Lassila, D
2006-02-21
A 3-D image correlation system, which measures the full-field displacements in 3 dimensions, has been used to experimentally determine the full deformation gradient matrix for two zinc single crystals. Based on the image correlation data, the slip system activity for the two crystals has been calculated. The results of the calculation show that for one crystal, only the primary slip system is active, which is consistent with traditional theory. The other crystal however, shows appreciable deformation on slip systems other than the primary. An analysis has been conducted which confirms the experimental observation that these other slip system deform in such a manner that the net result is slip which is approximately one third the magnitude and directly orthogonal to the primary system.
Angular distribution of Auger electrons due to 3d-shell ionization of krypton
NASA Technical Reports Server (NTRS)
Omidvar, K.
1977-01-01
Cross sections for electron impact ionization of krypton due to ejection of a 3rd shell electron have been calculated using screened hydrogenic and Hartree-Slater wave functions for target atom. While the total ionization cross sections in the two approximations are within 10% of each other, the Auger electron angular distribution, related to cross sections for specific magnetic quantum numbers of the 3rd electrons, is widely different in the two approximations. The angular distribution due to Hartree-Slater approximation is in excellent agreement with measurement. The physical reason for the discrepancies in the two approximations is explained.
[The reconstruction of welding arc 3D electron density distribution based on Stark broadening].
Zhang, Wang; Hua, Xue-Ming; Pan, Cheng-Gang; Li, Fang; Wang, Min
2012-10-01
The three-dimensional electron density is very important for welding arc quality control. In the present paper, Side-on characteristic line profile was collected by a spectrometer, and the lateral experimental data were approximated by a polynomial fitting. By applying an Abel inversion technique, the authors obtained the radial intensity distribution at each wavelength and thus constructed a profile for the radial positions. The Fourier transform was used to separate the Lorentz linear from the spectrum reconstructed, thus got the accurate Stark width. And we calculated the electronic density three-dimensional distribution of the TIG welding are plasma.
Resonant structure of the 3d electron`s angular distribution in a free Mn{sup +}Ion
Amusia, M.Y.; Dolmatov, V.K.
1995-08-01
The 3d-electron angular anisotropy parameter of the free Mn{sup +} ion is calculated using the {open_quotes}spin-polarized{close_quotes} random-phase approximation with exchange. Strong resonance structure is discovered, which is due to interference with the powerful 3p {yields} 3d discrete excitation. The effect of the 3p {yields} 4s transition is also noticeable. The ordering of these respective resonances with phonon energy increase proved to be opposite in angular anisotropy parameter to that in 3d-photoionization cross section. A paper describing these results was published.
Stumpe, Martin C.; Blinov, Nikolay; Wishart, David; Kovalenko, Andriy; Pande, Vijay S.
2010-01-01
Water plays a unique role in all living organisms. Not only is it nature’s ubiquitous solvent, but it also actively takes part in many cellular processes. In particular, the structure and properties of interfacial water near biomolecules like proteins are often related to the function of the respective molecule. It can therefore be highly instructive to study the local water density around solutes in cellular systems, particularly when solvent-mediated forces like the hydrophobic effect are relevant. Computational methods like molecular dynamics (MD) simulations seem well suited to study these systems at the atomic level. However, due to sampling requirements, it is not clear that MD simulations are indeed the method of choice to obtain converged densities at a given level of precision. We here compare the calculation of local water densities with two different methods, MD simulations and the three-dimensional reference interaction site model with the Kovalenko-Hirata closure (3D-RISM-KH). In particular, we investigate the convergence of the local water density to assess the required simulation times for different levels of resolution. Moreover, we provide a quantitative comparison of the densities calculated with MD and with 3D-RISM-KH, and investigate the effect of the choice of the water model for both methods. Our results show that 3D-RISM-KH yields density distributions that are very similar to those from MD up to a 0.5 Å resolution, but for significantly reduced computational cost. The combined use of MD and 3D-RISM-KH emerges as an auspicious perspective for efficient solvent sampling in dynamical systems. PMID:21174421
A Novel 3D Multilateration Sensor Using Distributed Ultrasonic Beacons for Indoor Navigation
Kapoor, Rohan; Ramasamy, Subramanian; Gardi, Alessandro; Bieber, Chad; Silverberg, Larry; Sabatini, Roberto
2016-01-01
Navigation and guidance systems are a critical part of any autonomous vehicle. In this paper, a novel sensor grid using 40 KHz ultrasonic transmitters is presented for adoption in indoor 3D positioning applications. In the proposed technique, a vehicle measures the arrival time of incoming ultrasonic signals and calculates the position without broadcasting to the grid. This system allows for conducting silent or covert operations and can also be used for the simultaneous navigation of a large number of vehicles. The transmitters and receivers employed are first described. Transmission lobe patterns and receiver directionality determine the geometry of transmitter clusters. Range and accuracy of measurements dictate the number of sensors required to navigate in a given volume. Laboratory experiments were performed in which a small array of transmitters was set up and the sensor system was tested for position accuracy. The prototype system is shown to have a 1-sigma position error of about 16 cm, with errors between 7 and 11 cm in the local horizontal coordinates. This research work provides foundations for the future development of ultrasonic navigation sensors for a variety of autonomous vehicle applications. PMID:27740604
A Novel 3D Multilateration Sensor Using Distributed Ultrasonic Beacons for Indoor Navigation.
Kapoor, Rohan; Ramasamy, Subramanian; Gardi, Alessandro; Bieber, Chad; Silverberg, Larry; Sabatini, Roberto
2016-10-08
Navigation and guidance systems are a critical part of any autonomous vehicle. In this paper, a novel sensor grid using 40 KHz ultrasonic transmitters is presented for adoption in indoor 3D positioning applications. In the proposed technique, a vehicle measures the arrival time of incoming ultrasonic signals and calculates the position without broadcasting to the grid. This system allows for conducting silent or covert operations and can also be used for the simultaneous navigation of a large number of vehicles. The transmitters and receivers employed are first described. Transmission lobe patterns and receiver directionality determine the geometry of transmitter clusters. Range and accuracy of measurements dictate the number of sensors required to navigate in a given volume. Laboratory experiments were performed in which a small array of transmitters was set up and the sensor system was tested for position accuracy. The prototype system is shown to have a 1-sigma position error of about 16 cm, with errors between 7 and 11 cm in the local horizontal coordinates. This research work provides foundations for the future development of ultrasonic navigation sensors for a variety of autonomous vehicle applications.
Stress distribution on external hexagon implant system using 3d finite element analysis.
Segundo, Regênio M H; Oshima, Hugo M S; Silva, Isaac N L; Júnior, Luis H B; Mota, Eduardo G; Coelho, Luiz F B
2007-01-01
The aim of this study was to compare and evaluate strain distribution on dental implant, abutment, screw and crown virtual models in the posterior region. The analysis was performed by means of a 3D virtual model developed by the PRO-ENGINEER System (PRO-ENGINEER, PTC, Needham, MA, USA ) with an external butt joint (3i Implant Innovations, Palm Beach, Florida), square headed Gold Tite abutment retainer screw (3i Implant Innovations, Palm Beach, Florida), STA abutment (3i Implant Innovations, Palm Beach, Florida), metal infrastructure of Ag-Pd alloy and feldspatic ceramic. The standard load was 382N at 15 degree angle to the implant axis, applied at 6 mm from the implant center at different observation points on the implant-screw set. The data showed that on the implant virtual model, the highest strain concentration was found at the interface between the implant platform and the abutment, and in the middle point of the 1st screw thread internal diameter on the load application side.
Three-axis distributed fiber optic strain measurement in 3D woven composite structures
NASA Astrophysics Data System (ADS)
Castellucci, Matt; Klute, Sandra; Lally, Evan M.; Froggatt, Mark E.; Lowry, David
2013-03-01
Recent advancements in composite materials technologies have broken further from traditional designs and require advanced instrumentation and analysis capabilities. Success or failure is highly dependent on design analysis and manufacturing processes. By monitoring smart structures throughout manufacturing and service life, residual and operational stresses can be assessed and structural integrity maintained. Composite smart structures can be manufactured by integrating fiber optic sensors into existing composite materials processes such as ply layup, filament winding and three-dimensional weaving. In this work optical fiber was integrated into 3D woven composite parts at a commercial woven products manufacturing facility. The fiber was then used to monitor the structures during a VARTM manufacturing process, and subsequent static and dynamic testing. Low cost telecommunications-grade optical fiber acts as the sensor using a high resolution commercial Optical Frequency Domain Reflectometer (OFDR) system providing distributed strain measurement at spatial resolutions as low as 2mm. Strain measurements using the optical fiber sensors are correlated to resistive strain gage measurements during static structural loading.
Calibration of an Outdoor Distributed Camera Network with a 3D Point Cloud
Ortega, Agustín; Silva, Manuel; Teniente, Ernesto H.; Ferreira, Ricardo; Bernardino, Alexandre; Gaspar, José; Andrade-Cetto, Juan
2014-01-01
Outdoor camera networks are becoming ubiquitous in critical urban areas of the largest cities around the world. Although current applications of camera networks are mostly tailored to video surveillance, recent research projects are exploiting their use to aid robotic systems in people-assisting tasks. Such systems require precise calibration of the internal and external parameters of the distributed camera network. Despite the fact that camera calibration has been an extensively studied topic, the development of practical methods for user-assisted calibration that minimize user intervention time and maximize precision still pose significant challenges. These camera systems have non-overlapping fields of view, are subject to environmental stress, and are likely to suffer frequent recalibration. In this paper, we propose the use of a 3D map covering the area to support the calibration process and develop an automated method that allows quick and precise calibration of a large camera network. We present two cases of study of the proposed calibration method: one is the calibration of the Barcelona Robot Lab camera network, which also includes direct mappings (homographies) between image coordinates and world points in the ground plane (walking areas) to support person and robot detection and localization algorithms. The second case consist of improving the GPS positioning of geo-tagged images taken with a mobile device in the Facultat de Matemàtiques i Estadística (FME) patio at the Universitat Politècnica de Catalunya (UPC). PMID:25076221
3D-Simulation Of Concentration Distributions Inside Large-Scale Circulating Fluidized Bed Combustors
NASA Astrophysics Data System (ADS)
Wischnewski, R.; Ratschow, L.; Hartge, E. U.; Werthe, J.
With increasing size of modern CFB combustors the lateral mixing of fuels and secondary air gains more and more importance. Strong concentration gradients, which result from improper lateral mixing, can lead to operational problems, high flue gas emissions and lower boiler efficiencies. A 3D-model for the simulation of local gas and solids concentrations inside industrial-sized CFB boilers has been developed. The model is based on a macroscopic approach and considers all major mechanisms during fuel spreading and subsequent combustion of char and volatiles. Typical characteristics of modern boilers like staged combustion, a smaller cross-sectional area in the lower section of the combustion chamber and the co-combustion of additional fuels with coal can be considered. The 252 MWth combustor of Stadtwerke Duisburg AG is used for the validation of the model. A comprehensive picture of the local conditions inside the combustion chamber is achieved by the combination of local gas measurements and the three-dimensional simulation of concentration distributions.
Calibration of an outdoor distributed camera network with a 3D point cloud.
Ortega, Agustín; Silva, Manuel; Teniente, Ernesto H; Ferreira, Ricardo; Bernardino, Alexandre; Gaspar, José; Andrade-Cetto, Juan
2014-07-29
Outdoor camera networks are becoming ubiquitous in critical urban areas of the largest cities around the world. Although current applications of camera networks are mostly tailored to video surveillance, recent research projects are exploiting their use to aid robotic systems in people-assisting tasks. Such systems require precise calibration of the internal and external parameters of the distributed camera network. Despite the fact that camera calibration has been an extensively studied topic, the development of practical methods for user-assisted calibration that minimize user intervention time and maximize precision still pose significant challenges. These camera systems have non-overlapping fields of view, are subject to environmental stress, and are likely to suffer frequent recalibration. In this paper, we propose the use of a 3D map covering the area to support the calibration process and develop an automated method that allows quick and precise calibration of a large camera network. We present two cases of study of the proposed calibration method: one is the calibration of the Barcelona Robot Lab camera network, which also includes direct mappings (homographies) between image coordinates and world points in the ground plane (walking areas) to support person and robot detection and localization algorithms. The second case consist of improving the GPS positioning of geo-tagged images taken with a mobile device in the Facultat de Matemàtiques i Estadística (FME) patio at the Universitat Politècnica de Catalunya (UPC).
Nanoscale 3D distribution of low melt and fluid fractions in mantle rocks
NASA Astrophysics Data System (ADS)
Gardes, Emmanuel; Morales, Luiz; Heinrich, Wilhelm; Sifre, David; Hashim, Leila; Gaillard, Fabrice; Katharina, Marquardt
2016-04-01
The presence of melts or fluids in the intergranular medium of rocks strongly influences their bulk physico-chemical properties (e.g. mass transport and chemical reactivity, electrical conductivity, seismic wave velocity, etc). Actually, the effects can be so large that only small melt or fluid fractions must sometimes be involved for explaining mantle geophysical discontinuities and anomalies. The investigation of the distribution of such small fractions in the intergranular medium of mantle rocks is therefore crucial for relating them to bulk and large scale properties. However, it involves submicrometric structures which are hardly characterizable using conventional techniques. Here we present how the FIB-SEM-STEM microscope can be used to produce 3D imaging at unequalled resolution. We show that low melt and fluid fractions can form films as thin as 20 nm at olivine grain boundaries, and that they can modify the physico-chemical properties of mantle rocks by orders of magnitude. The fine relationships between films at grain boundaries, tubules at triple junctions and pockets at grain corners can be explored, and appear to be complex and to differ from usual visions.
The Effect of Framework Design on Stress Distribution in Implant-Supported FPDs: A 3-D FEM Study
Eraslan, Oguz; Inan, Ozgur; Secilmis, Asli
2010-01-01
Objectives: The biomechanical behavior of the superstructure plays an important role in the functional longevity of dental implants. However, information about the influence of framework design on stresses transmitted to the implants and supporting tissues is limited. The purpose of this study was to evaluate the effects of framework designs on stress distribution at the supporting bone and supporting implants. Methods: In this study, the three-dimensional (3D) finite element stress analysis method was used. Three types of 3D mathematical models simulating three different framework designs for implant-supported 3-unit posterior fixed partial dentures were prepared with supporting structures. Convex (1), concave (2), and conventional (3) pontic framework designs were simulated. A 300-N static vertical occlusal load was applied on the node at the center of occlusal surface of the pontic to calculate the stress distributions. As a second condition, frameworks were directly loaded to evaluate the effect of the framework design clearly. The Solidworks/Cosmosworks structural analysis programs were used for finite element modeling/analysis. Results: The analysis of the von Mises stress values revealed that maximum stress concentrations were located at the loading areas for all models. The pontic side marginal edges of restorations and the necks of implants were other stress concentration regions. There was no clear difference among models when the restorations were loaded at occlusal surfaces. When the veneering porcelain was removed, and load was applied directly to the framework, there was a clear increase in stress concentration with a concave design on supporting implants and bone structure. Conclusions: The present study showed that the use of a concave design in the pontic frameworks of fixed partial dentures increases the von Mises stress levels on implant abutments and supporting bone structure. However, the veneering porcelain element reduces the effect of the
Chen, Xueli; Gao, Xinbo; Chen, Duofang; Ma, Xiaopeng; Zhao, Xiaohui; Shen, Man; Li, Xiangsi; Qu, Xiaochao; Liang, Jimin; Ripoll, Jorge; Tian, Jie
2010-09-13
Optical tomography can demonstrate accurate three-dimensional (3D) imaging that recovers the 3D spatial distribution and concentration of the luminescent probes in biological tissues, compared with planar imaging. However, the tomographic approach is extremely difficult to implement due to the complexity in the reconstruction of 3D surface flux distribution from multi-view two dimensional (2D) measurements on the subject surface. To handle this problem, a novel and effective method is proposed in this paper to determine the surface flux distribution from multi-view 2D photographic images acquired by a set of non-contact detectors. The method is validated with comparison experiments involving both regular and irregular surfaces. Reconstruction of the inside probes based on the reconstructed surface flux distribution further demonstrates the potential of the proposed method in its application in optical tomography.
NASA Astrophysics Data System (ADS)
Sanfratello, L.; Fukushima, E.
2009-06-01
We recently developed a novel extension of MR Elastograpy (MRE) to image the force chain structure within a dense 3D quasi-static granular assembly. Subsequently, computer codes and algorithms to determine the distribution of the force chain lengths, where a chain is taken to be a relatively straight section between branching points, were developed. Similar tools were used previously to analyze 2D photoelastic data and now have been expanded to analyze our most current 3D MRE force chain data. These investigations reveal that the distribution of the chain lengths in 3D decays exponentially, as was observed in 2D. The exponential decay of the length distribution is consistent with DEM simulation results of Peters, et al. We conclude that the decay length of this distribution is a meaningful quantitative measure that characterizes granular assemblies.
NASA Astrophysics Data System (ADS)
Mok, Alex W. K.; Wong, Cheuk-Ping; Sit, Wai-Yu
2012-10-01
Using the helicity formalism, we calculate the combined angular distribution function of the two photons (γ1 and γ2) and electron ( e -) in the cascade process overline{p}pto {}^3{D_3}to {}^3{P_2}+{γ_1}to ( {ψ +{γ_2}} )+{γ_1}to ( {{e+}+{e-}} )+{γ_2}+{γ_1},when overline{p} and p are unpolarized. We also derive six different partially integrated angular distribution functions which give the angular distributions of one or two particles in the final state. Once the angular distributions are measured, our expressions will enable one to determine the relative magnitudes as well as the cosines of the relative phases of all the angular-momentum helicity amplitudes in the radiative decay processes 3 D 3 → 3 P 2 + γ1 and 3 P 2 → ψ + γ2.
Burkatzki, M; Filippi, Claudia; Dolg, M
2008-10-28
We extend our recently published set of energy-consistent scalar-relativistic Hartree-Fock pseudopotentials by the 3d-transition metal elements, scandium through zinc. The pseudopotentials do not exhibit a singularity at the nucleus and are therefore suitable for quantum Monte Carlo (QMC) calculations. The pseudopotentials and the accompanying basis sets (VnZ with n=T,Q) are given in standard Gaussian representation and their parameter sets are presented. Coupled cluster, configuration interaction, and QMC studies are carried out for the scandium and titanium atoms and their oxides, demonstrating the good performance of the pseudopotentials. Even though the choice of pseudopotential form is motivated by QMC, these pseudopotentials can also be employed in other quantum chemical approaches.
Effects of oxygen vacancy on 3d transition-metal doped anatase TiO2: First principles calculations
NASA Astrophysics Data System (ADS)
Zhao, Ya Fei; Li, Can; Lu, Song; Yan, Li Jin; Gong, Yin Yan; Niu, Leng Yuan; Liu, Xin Juan
2016-03-01
In this work, systematic study of the formation energy, crystalline and electronic structures of 3d transition metal (Sc, V, Cr, Mn, Fe, Co and Ni) doped anatase TiO2 specimens with and without oxygen vacancy has been carried out by the first principles calculations. The impurity states located at the band gaps enhance the visible light absorption, and the oxygen vacancy result in the EF move into the CB for some doped systems, which induce the Ti3+ ions and promote the separation of photogenerated carriers. Doping and oxygen vacancy can change the hybrid strength and MP value of TMsbnd O bonding which has the approximately linearly with the band gap.
Dimenna, R.A.; Lee, S.Y.
1995-05-01
The application of computational fluid dynamics methods to the analysis of mixing in the high level waste tanks at the Savannah River Site requires a demonstration that the computer codes can properly represent the behavior of fluids in the tanks. The motive force for mixing the tanks is a set of jet pumps taking suction from the tank fluid and discharging turbulent jets near the bottom of the tank. The work described here focuses on the free turbulent jet in water as the simplest case of jet behavior for which data could be found in the open literature. Calculations performed with both CFDS-FLOW3D and FLUENT were compared with data as well as classical jet theory. Results showed both codes agreed reasonably well with each other and with the data, but that results were sensitive to the computational mesh and, to a lesser degree, the selection of turbulence models.
NASA Astrophysics Data System (ADS)
Chang, Chenliang; Qi, Yijun; Wu, Jun; Yuan, Caojin; Nie, Shouping; Xia, Jun
2017-03-01
A method of calculating computer-generated hologram (CGH) for color holographic 3D projection is proposed. A color 3D object is decomposed into red, green and blue components. For each color component, a virtual wavefront recording plane (WRP) is established which is nonuniformly sampled according to the depth map of the 3D object. The hologram of each color component is calculated from the nonuniform sampled WRP using the shifted Fresnel diffraction algorithm. Finally three holograms of RGB components are encoded into one single CGH based on the multiplexing encoding method. The computational cost of CGH generation is reduced by converting diffraction calculation from huge 3D voxels to three 2D planar images. Numerical experimental results show that the CGH generated by our method is capable to project zoomable color 3D object with clear quality.
Anderson, David M G; Van de Plas, Raf; Rose, Kristie L; Hill, Salisha; Schey, Kevin L; Solga, Anne C; Gutmann, David H; Caprioli, Richard M
2016-10-21
Neurofibromatosis type 1 (NF1) is a common neurogenetic disorder, in which affected individuals develop tumors of the nervous system. Children with NF1 are particularly prone to brain tumors (gliomas) involving the optic pathway that can result in impaired vision. Since tumor formation and expansion requires a cooperative tumor microenvironment, it is important to identify the cellular and acellular components associated with glioma development and growth. In this study, we used 3-D matrix assisted laser desorption ionization imaging mass spectrometry (MALDI IMS) to measure the distributions of multiple molecular species throughout optic nerve tissue in mice with and without glioma, and to explore their spatial relationships within the 3-D volume of the optic nerve and chiasm. 3-D IMS studies often involve extensive workflows due to the high volume of sections required to generate high quality 3-D images. Herein, we present a workflow for 3-D data acquisition and volume reconstruction using mouse optic nerve tissue. The resulting 3-D IMS data yield both molecular similarities and differences between glioma-bearing and wild-type (WT) tissues, including protein distributions localizing to different anatomical subregions.
Rey, Michaël; Nikitin, Andrei V; Tyuterev, Vladimir G
2014-07-28
Accurate variational high-resolution spectra calculations in the range 0-8000 cm(-1) are reported for the first time for the monodeutered methane ((12)CH3D). Global calculations were performed by using recent ab initio surfaces for line positions and line intensities derived from the main isotopologue (12)CH4. Calculation of excited vibrational levels and high-J rovibrational states is described by using the normal mode Eckart-Watson Hamiltonian combined with irreducible tensor formalism and appropriate numerical procedures for solving the quantum nuclear motion problem. The isotopic H→D substitution is studied in details by means of symmetry and nonlinear normal mode coordinate transformations. Theoretical spectra predictions are given up to J = 25 and compared with the HITRAN 2012 database representing a compilation of line lists derived from analyses of experimental spectra. The results are in very good agreement with available empirical data suggesting that a large number of yet unassigned lines in observed spectra could be identified and modeled using the present approach.
Rey, Michaël Tyuterev, Vladimir G.; Nikitin, Andrei V.
2014-07-28
Accurate variational high-resolution spectra calculations in the range 0-8000 cm{sup −1} are reported for the first time for the monodeutered methane ({sup 12}CH{sub 3}D). Global calculations were performed by using recent ab initio surfaces for line positions and line intensities derived from the main isotopologue {sup 12}CH{sub 4}. Calculation of excited vibrational levels and high-J rovibrational states is described by using the normal mode Eckart-Watson Hamiltonian combined with irreducible tensor formalism and appropriate numerical procedures for solving the quantum nuclear motion problem. The isotopic H→D substitution is studied in details by means of symmetry and nonlinear normal mode coordinate transformations. Theoretical spectra predictions are given up to J = 25 and compared with the HITRAN 2012 database representing a compilation of line lists derived from analyses of experimental spectra. The results are in very good agreement with available empirical data suggesting that a large number of yet unassigned lines in observed spectra could be identified and modeled using the present approach.
NASA Astrophysics Data System (ADS)
Rey, Michaël; Nikitin, Andrei V.; Tyuterev, Vladimir G.
2014-07-01
Accurate variational high-resolution spectra calculations in the range 0-8000 cm-1 are reported for the first time for the monodeutered methane (12CH3D). Global calculations were performed by using recent ab initio surfaces for line positions and line intensities derived from the main isotopologue 12CH4. Calculation of excited vibrational levels and high-J rovibrational states is described by using the normal mode Eckart-Watson Hamiltonian combined with irreducible tensor formalism and appropriate numerical procedures for solving the quantum nuclear motion problem. The isotopic H→D substitution is studied in details by means of symmetry and nonlinear normal mode coordinate transformations. Theoretical spectra predictions are given up to J = 25 and compared with the HITRAN 2012 database representing a compilation of line lists derived from analyses of experimental spectra. The results are in very good agreement with available empirical data suggesting that a large number of yet unassigned lines in observed spectra could be identified and modeled using the present approach.
NASA Astrophysics Data System (ADS)
Datta, Shubhashish; Rajagopalan, Sruti; Lemke, Shaun; Joshi, Abhay
2014-06-01
We report a balanced PIN-TIA photoreceiver integrated with a 3 dB fiber coupler for distributed fiber optic sensors. This detector demonstrates -3 dB bandwidth >15 GHz and coupled conversion gain >65 V/W per photodiode through either input port of the 3 dB coupler, and can be operated at local oscillator power of +17 dBm. The combined common mode rejection of the balanced photoreceiver and the integrated 3 dB coupler is >20 dB. We also present measurement results with various optical stimuli, namely impulses, sinusoids, and pseudo-random sequences, which are relevant for time domain reflectometry, frequency domain reflectometry, and code correlation sensors, respectively.
Wake, Kanako; Varsier, Nadège; Watanabe, Soichi; Taki, Masao; Wiart, Joe; Mann, Simon; Deltour, Isabelle; Cardis, Elisabeth
2009-10-07
A worldwide epidemiological study called 'INTERPHONE' has been conducted to estimate the hypothetical relationship between brain tumors and mobile phone use. In this study, we proposed a method to estimate 3D distribution of the specific absorption rate (SAR) in the human head due to mobile phone use to provide the exposure gradient for epidemiological studies. 3D SAR distributions due to exposure to an electromagnetic field from mobile phones are estimated from mobile phone compliance testing data for actual devices. The data for compliance testing are measured only on the surface in the region near the device and in a small 3D region around the maximum on the surface in a homogeneous phantom with a specific shape. The method includes an interpolation/extrapolation and a head shape conversion. With the interpolation/extrapolation, SAR distributions in the whole head are estimated from the limited measured data. 3D SAR distributions in the numerical head models, where the tumor location is identified in the epidemiological studies, are obtained from measured SAR data with the head shape conversion by projection. Validation of the proposed method was performed experimentally and numerically. It was confirmed that the proposed method provided good estimation of 3D SAR distribution in the head, especially in the brain, which is the tissue of major interest in epidemiological studies. We conclude that it is possible to estimate 3D SAR distributions in a realistic head model from the data obtained by compliance testing measurements to provide a measure for the exposure gradient in specific locations of the brain for the purpose of exposure assessment in epidemiological studies. The proposed method has been used in several studies in the INTERPHONE.
NASA Astrophysics Data System (ADS)
Wake, Kanako; Varsier, Nadège; Watanabe, Soichi; Taki, Masao; Wiart, Joe; Mann, Simon; Deltour, Isabelle; Cardis, Elisabeth
2009-10-01
A worldwide epidemiological study called 'INTERPHONE' has been conducted to estimate the hypothetical relationship between brain tumors and mobile phone use. In this study, we proposed a method to estimate 3D distribution of the specific absorption rate (SAR) in the human head due to mobile phone use to provide the exposure gradient for epidemiological studies. 3D SAR distributions due to exposure to an electromagnetic field from mobile phones are estimated from mobile phone compliance testing data for actual devices. The data for compliance testing are measured only on the surface in the region near the device and in a small 3D region around the maximum on the surface in a homogeneous phantom with a specific shape. The method includes an interpolation/extrapolation and a head shape conversion. With the interpolation/extrapolation, SAR distributions in the whole head are estimated from the limited measured data. 3D SAR distributions in the numerical head models, where the tumor location is identified in the epidemiological studies, are obtained from measured SAR data with the head shape conversion by projection. Validation of the proposed method was performed experimentally and numerically. It was confirmed that the proposed method provided good estimation of 3D SAR distribution in the head, especially in the brain, which is the tissue of major interest in epidemiological studies. We conclude that it is possible to estimate 3D SAR distributions in a realistic head model from the data obtained by compliance testing measurements to provide a measure for the exposure gradient in specific locations of the brain for the purpose of exposure assessment in epidemiological studies. The proposed method has been used in several studies in the INTERPHONE.
NASA Astrophysics Data System (ADS)
Darcel, C.; Davy, P.; Bour, O.; de Dreuzy, J.
2006-12-01
Considering the role of fractures in hydraulic flow, the knowledge of the 3D spatial distribution of fractures is a basic concern for any hydrogeology-related study (potential leakages in waste repository, aquifer management, ?). Unfortunately geophysical imagery is quite blind with regard to fractures, and only the largest ones are generally detected, if they are. Actually most of the information has to be derived from statistical models whose parameters are defined from a few sparse sampling areas, such as wells, outcrops, or lineament maps. How these observations obtained at different scales can be linked to each other is a critical point, which directly addresses the issue of fracture scaling. In this study, we use one of the most important datasets that have ever been collected for characterizing fracture networks. It was collected by the Swedish company SKB for their research program on deep repository for radioactive waste, and consists of large-scale lineament maps covering about 100 km2, several outcrops of several hundreds of m2 mapped with a fracture trace length resolution down to 0.50 m, and a series of 1000m-deep cored boreholes where both fracture orientations and fracture intensities were carefully recorded. Boreholes are an essential complement to surface outcrops as they allow the sampling of horizontal fracture planes that, generally, are severely undersampled in subhorizontal outcrops. Outcrops, on the other hand, provide information on fracture sizes which is not possible to address from core information alone. However linking outcrops and boreholes is not straightforward: the sampling scale is obviously different and some scaling rules have to be applied to relate both fracture distributions; outcrops are 2D planes while boreholes are mostly 1D records; outcrops can be affected by superficial fracturing processes that are not representative of the fracturing at depth. We present here the stereology methods for calculating the 3D distribution
NASA Astrophysics Data System (ADS)
Lougovski, A.; Hofheinz, F.; Maus, J.; Schramm, G.; Will, E.; van den Hoff, J.
2014-02-01
The aim of this study is the evaluation of on-the-fly volume of intersection computation for system’s geometry modelling in 3D PET image reconstruction. For this purpose we propose a simple geometrical model in which the cubic image voxels on the given Cartesian grid are approximated with spheres and the rectangular tubes of response (ToRs) are approximated with cylinders. The model was integrated into a fully 3D list-mode PET reconstruction for performance evaluation. In our model the volume of intersection between a voxel and the ToR is only a function of the impact parameter (the distance between voxel centre to ToR axis) but is independent of the relative orientation of voxel and ToR. This substantially reduces the computational complexity of the system matrix calculation. Based on phantom measurements it was determined that adjusting the diameters of the spherical voxel size and the ToR in such a way that the actual voxel and ToR volumes are conserved leads to the best compromise between high spatial resolution, low noise, and suppression of Gibbs artefacts in the reconstructed images. Phantom as well as clinical datasets from two different PET systems (Siemens ECAT HR+ and Philips Ingenuity-TF PET/MR) were processed using the developed and the respective vendor-provided (line of intersection related) reconstruction algorithms. A comparison of the reconstructed images demonstrated very good performance of the new approach. The evaluation showed the respective vendor-provided reconstruction algorithms to possess 34-41% lower resolution compared to the developed one while exhibiting comparable noise levels. Contrary to explicit point spread function modelling our model has a simple straight-forward implementation and it should be easy to integrate into existing reconstruction software, making it competitive to other existing resolution recovery techniques.
Ferrero, Mauro; Rérat, Michel; Orlando, Roberto; Dovesi, Roberto
2008-07-15
The Coupled Perturbed Hartree-Fock (CPHF) scheme has been implemented in the CRYSTAL06 program, that uses a gaussian type basis set, for systems periodic in 1D (polymers), 2D (slabs), 3D (crystals) and, as a limiting case, 0D (molecules), which enables comparison with molecular codes. CPHF is applied to the calculation of the polarizability alpha of LiF in different aggregation states: finite and infinite chains, slabs, and cubic crystal. Correctness of the computational scheme for the various dimensionalities and its numerical efficiency are confirmed by the correct trend of alpha: alpha for a finite linear chain containing N LiF units with large N tends to the value for the infinite chain, N parallel chains give the slab value when N is sufficiently large, and N superimposed slabs tend to the bulk value. CPHF results compare well with those obtained with a saw-tooth potential approach, previously implemented in CRYSTAL. High numerical accuracy can easily be achieved at relatively low cost, with the same kind of dependence on the computational parameters as for the SCF cycle. Overall, the cost of one component of the dielectric tensor is roughly the same as for the SCF cycle, and it is dominated by the calculation of two-electron four-center integrals.
Guo, Yanrong; Shao, Yeqin; Gao, Yaozong; Price, True; Oto, Aytekin; Shen, Dinggang
2014-07-15
patches of the prostate surface and trained to adaptively capture the appearance in different prostate zones, thus achieving better local tissue differentiation. For each local region, multiple classifiers are trained based on the randomly selected samples and finally assembled by a specific fusion method. In addition to this nonparametric appearance model, a prostate shape model is learned from the shape statistics using a novel approach, sparse shape composition, which can model nonGaussian distributions of shape variation and regularize the 3D mesh deformation by constraining it within the observed shape subspace. Results: The proposed method has been evaluated on two datasets consisting of T2-weighted MR prostate images. For the first (internal) dataset, the classification effectiveness of the authors' improved dictionary learning has been validated by comparing it with three other variants of traditional dictionary learning methods. The experimental results show that the authors' method yields a Dice Ratio of 89.1% compared to the manual segmentation, which is more accurate than the three state-of-the-art MR prostate segmentation methods under comparison. For the second dataset, the MICCAI 2012 challenge dataset, the authors' proposed method yields a Dice Ratio of 87.4%, which also achieves better segmentation accuracy than other methods under comparison. Conclusions: A new magnetic resonance image prostate segmentation method is proposed based on the combination of deformable model and dictionary learning methods, which achieves more accurate segmentation performance on prostate T2 MR images.
Guo, Yanrong; Gao, Yaozong; Shao, Yeqin; Price, True; Oto, Aytekin; Shen, Dinggang
2014-01-01
patches of the prostate surface and trained to adaptively capture the appearance in different prostate zones, thus achieving better local tissue differentiation. For each local region, multiple classifiers are trained based on the randomly selected samples and finally assembled by a specific fusion method. In addition to this nonparametric appearance model, a prostate shape model is learned from the shape statistics using a novel approach, sparse shape composition, which can model nonGaussian distributions of shape variation and regularize the 3D mesh deformation by constraining it within the observed shape subspace. Results: The proposed method has been evaluated on two datasets consisting of T2-weighted MR prostate images. For the first (internal) dataset, the classification effectiveness of the authors' improved dictionary learning has been validated by comparing it with three other variants of traditional dictionary learning methods. The experimental results show that the authors' method yields a Dice Ratio of 89.1% compared to the manual segmentation, which is more accurate than the three state-of-the-art MR prostate segmentation methods under comparison. For the second dataset, the MICCAI 2012 challenge dataset, the authors' proposed method yields a Dice Ratio of 87.4%, which also achieves better segmentation accuracy than other methods under comparison. Conclusions: A new magnetic resonance image prostate segmentation method is proposed based on the combination of deformable model and dictionary learning methods, which achieves more accurate segmentation performance on prostate T2 MR images. PMID:24989402
3D Quantitative Confocal Laser Microscopy of Ilmenite Volume Distribution in Alpe Arami Olivine
NASA Astrophysics Data System (ADS)
Bozhilov, K. N.
2001-12-01
The deep origin of the Alpe Arami garnet lherzolite massif in the Swiss Alps proposed by Dobrzhinetskaya et al. (Science, 1996) has been a focus of heated debate. One of the lines of evidence supporting an exhumation from more than 200 km depth includes the abundance, distribution, and orientation of magnesian ilmenite rods in the oldest generation of olivine. This argument has been disputed in terms of the abundance of ilmenite and consequently the maximum TiO2 content in the discussed olivine. In order to address this issue, we have directly measured the volume fraction of ilmenite of the oldest generation of olivine by applying confocal laser scanning microscopy (CLSM). CLSM is a method which allows for three-dimensional imaging and quantitative volume determination by optical sectioning of the objects. The images for 3D reconstruction and measurements were acquired from petrographic thin sections in reflected laser light with 488 nm wavelength. Measurements of more than 80 olivine grains in six thin sections of our material yielded an average volume fraction of 0.31% ilmenite in the oldest generation of olivine from Alpe Arami. This translates into 0.23 wt.% TiO2 in olivine with error in determination of ±0.097 wt.%, a value significantly different from that of 0.02 to 0.03 wt.% TiO2 determined by Hacker et al. (Science, 1997) by a broad-beam microanalysis technique. During the complex geological history of the Alpe Arami massif, several events of metamorphism are recorded which all could have caused increased mobility of the mineral components. Evidence for loss of TiO2 from olivine is the tendency for high densities of ilmenite to be restricted to cores of old grains, the complete absence of ilmenite inclusions from the younger, recrystallized, generation of olivine, and reduction in ilmenite size and abundance in more serpentinized specimens. These observations suggest that only olivine grains with the highest concentrations of ilmenite are close to the
Number Density Distributions of Ultracold Bosons in 3D Optical Lattices
NASA Astrophysics Data System (ADS)
Garrett, Joe; Duchon, Eric; Trivedi, Nandini
2011-03-01
We calculate the probability, P (n) , of finding n bosons at a site and the probability of hopping in a uniform optical lattice as a function of the temperature, T , and the repulsive interaction between bosons, U / t , as a function of hopping energy. We examine the characteristic P (n) distribution for the Mott Insulator, quantum critical region and superfluid and determine its behavior across thermal and quantum phase transitions using quantum Monte Carlo. The behavior of the local kinetic energy is estimated using the probability of hopping. These results illuminate number squeezing in the Mott Insulator and the quantum critical region described in. This research was funded by The Ohio State University Physics Department's Harold McMaster Scholarship and ARO grand number W911NF-08-1-0338.
A Portable 3D FFT Package for Distributed-Memory Parallel Architectures
NASA Technical Reports Server (NTRS)
Ding, H. Q.; Ferraro, R. D.; Gennery, D. B.
1995-01-01
A parallel algorithm for 3D FFTs is implemented as a series of local 1D FFTs combined with data transposes. This allows the use of vendor supplied (often fully optimized) sequential 1D FFTs. The FFTs are carried out in-place by using an in-place data transpose across the processors.
Supporting Distributed Team Working in 3D Virtual Worlds: A Case Study in Second Life
ERIC Educational Resources Information Center
Minocha, Shailey; Morse, David R.
2010-01-01
Purpose: The purpose of this paper is to report on a study into how a three-dimensional (3D) virtual world (Second Life) can facilitate socialisation and team working among students working on a team project at a distance. This models the situation in many commercial sectors where work is increasingly being conducted across time zones and between…
Supporting Distributed Team Working in 3D Virtual Worlds: A Case Study in Second Life
ERIC Educational Resources Information Center
Minocha, Shailey; Morse, David R.
2010-01-01
Purpose: The purpose of this paper is to report on a study into how a three-dimensional (3D) virtual world (Second Life) can facilitate socialisation and team working among students working on a team project at a distance. This models the situation in many commercial sectors where work is increasingly being conducted across time zones and between…
NASA Astrophysics Data System (ADS)
Gunár, S.; Mackay, D. H.
2016-07-01
Aims: We analyze distributions of the magnetic field strength and prominence plasma (temperature, pressure, plasma β, and mass) using the 3D whole-prominence fine structure model. Methods: The model combines a 3D magnetic field configuration of an entire prominence, obtained from non-linear force-free field simulations, with a detailed semi-empirically derived description of the prominence plasma. The plasma is located in magnetic dips in hydrostatic equilibrium and is distributed along multiple fine structures within the 3D magnetic model. Results: We show that in the modeled prominence, the variations of the magnetic field strength and its orientation are insignificant on scales comparable to the smallest dimensions of the observed prominence fine structures. We also show the ability of the 3D whole-prominence fine structure model to reveal the distribution of the prominence plasma with respect to its temperature within the prominence volume. This provides new insights into the composition of the prominence-corona transition region. We further demonstrate that the values of the plasma β are small throughout the majority of the modeled prominences when realistic photospheric magnetic flux distributions and prominence plasma parameters are assumed. While this is generally true, we also find that in the region with the deepest magnetic dips, the plasma β may increase towards unity. Finally, we show that the mass of the modeled prominence plasma is in good agreement with the mass of observed non-eruptive prominences.
Mapping molecular orientational distributions for biological sample in 3D (Conference Presentation)
NASA Astrophysics Data System (ADS)
HE, Wei; Ferrand, Patrick; Richter, Benjamin; Bastmeyer, Martin; Brasselet, Sophie
2016-04-01
Measuring molecular orientation properties is very appealing for scientists in molecular and cell biology, as well as biomedical research. Orientational organization at the molecular scale is indeed an important brick to cells and tissues morphology, mechanics, functions and pathologies. Recent work has shown that polarized fluorescence imaging, based on excitation polarization tuning in the sample plane, is able to probe molecular orientational order in biological samples; however this applies only to information in 2D, projected in the sample plane. To surpass this limitation, we extended this approach to excitation polarization tuning in 3D. The principle is based on the decomposition of any arbitrary 3D linear excitation in a polarization along the longitudinal z-axis, and a polarization in the transverse xy-sample plane. We designed an interferometer with one arm generating radial polarization light (thus producing longitudinal polarization under high numerical aperture focusing), the other arm controlling a linear polarization in the transverse plane. The amplitude ratio between the two arms can vary so as to get any linear polarized excitation in 3D at the focus of a high NA objective. This technique has been characterized by polarimetry imaging at the back focal plane of the focusing objective, and modeled theoretically. 3D polarized fluorescence microscopy is demonstrated on actin stress fibers in non-flat cells suspended on synthetic polymer structures forming supporting pillars, for which heterogeneous actin orientational order could be identified. This technique shows a great potential in structural investigations in 3D biological systems, such as cell spheroids and tissues.
Confocal (micro)-XRF for 3D anlaysis of elements distribution in hot environmental particles
Bielewski, M; Eriksson, M; Himbert, J; Simon, R; Betti, M; Hamilton, T F
2007-11-27
calculations. In figure 1 the distributions of Pu, Fe and Ti obtained for one of the studied hot particles are presented. The strongest signal was recorded for plutonium; the signals from iron and titanium are respectively 14 and 38 times less. It means that Pu is the most abundant of the observed elements. However, since the light elements are not detectable with the applied measurement conditions, it cannot be definitely stated if plutonium is the main element present in the sample. The isosurfaces are calculated at 20 % of maximum intensity for each element. Please note that the isosurfaces on the drawing are transparent. Changes in the spatial distribution of Pu, Fe, and Ti within the particle are shown in Fig. 2a, 2b, and 2c. Distinct elemental patterns are clearly visible at the higher concentration levels. The distributions of Cr, Cu, and Pb were also reconstructed but the results are not presented here. As it is shown in Fig. 1, the correlation between elements is good at low concentrations but the maxima of concentrations are not strongly correlated (see Fig. 2.). In general, the particle is inhomogeneous in terms of its elemental composition. Similar inhomogeneities were found for other particles with Pu identified as a major element in three of the six particles examined.
Harvey, R.W.; Chan, V.S.
1996-12-31
Runaway of electrons to high energy during plasma disruptions occurs due to large induced toroidal electric fields which tend to maintain the toroidal plasma current, in accord with Lenz law. This has been observed in many tokamaks. Within the closed flux surfaces, the bounce-averaged CQL3D Fokker-Planck code is well suited to obtain the resulting electron distributions, nonthermal contributions to electrical conductivity, and runaway rates. The time-dependent 2D in momentum-space (p{sub {parallel}} and p{sub {perpendicular}}) distributions axe calculated on a radial array of noncircular flux surfaces, including bounce-averaging of the Fokker-Planck equation to account for toroidal trapping effects. In the steady state, the resulting distributions represent a balance between applied toroidal electric field, relativistic Coulomb collisions, and synchrotron radiation. The code can be run in a mode where the electrons are sourced at low velocity and run off the high velocity edge of the computational mesh, giving runaway rates at steady state. At small minor radius, the results closely match previous results reported by Kulsrud et al. It is found that the runaway rate has a strong dependence on inverse aspect ratio e, decreasing by a factor {approx} 5 as e increases from 0.0 to 0.3. The code can also be run with a radial diffusion and pinching term, simulating radial transport with plasma pinching to maintain a given density profile. Results show a transport reduction of runaways in the plasma center, and an enhancement towards the edge due to the electrons from the plasma center. Avalanching of runaways due to a knock-on electron source is being included.
NASA Astrophysics Data System (ADS)
Hrobárik, Peter; Reviakine, Roman; Arbuznikov, Alexei V.; Malkina, Olga L.; Malkin, Vladimir G.; Köhler, Frank H.; Kaupp, Martin
2007-01-01
The calculation of nuclear shieldings for paramagnetic molecules has been implemented in the ReSpect program, which allows the use of modern density functional methods with accurate treatments of spin-orbit effects for all relevant terms up to order O(α4) in the fine structure constant. Compared to previous implementations, the methodology has been extended to compounds of arbitrary spin multiplicity. Effects of zero-field splittings in high-spin systems are approximately accounted for. Validation of the new implementation is carried out for the C13 and H1 NMR signal shifts of the 3d metallocenes V4Cp2, Cr3Cp2, Mn2Cp2, Mn6Cp2, Co2Cp2, and Ni3Cp2. Zero-field splitting effects on isotropic shifts tend to be small or negligible. Agreement with experimental isotropic shifts is already good with the BP86 gradient-corrected functional and is further improved by admixture of Hartree-Fock exchange in hybrid functionals. Decomposition of the shieldings confirms the dominant importance of the Fermi-contact shifts, but contributions from spin-orbit dependent terms are frequently also non-negligible. Agreement with C13 NMR shift tensors from solid-state experiments is of similar quality as for isotropic shifts.
Gimenez, Y; Busser, B; Trichard, F; Kulesza, A; Laurent, J M; Zaun, V; Lux, F; Benoit, J M; Panczer, G; Dugourd, P; Tillement, O; Pelascini, F; Sancey, L; Motto-Ros, V
2016-07-20
Nanomaterials represent a rapidly expanding area of research with huge potential for future medical applications. Nanotechnology indeed promises to revolutionize diagnostics, drug delivery, gene therapy, and many other areas of research. For any biological investigation involving nanomaterials, it is crucial to study the behavior of such nano-objects within tissues to evaluate both their efficacy and their toxicity. Here, we provide the first account of 3D label-free nanoparticle imaging at the entire-organ scale. The technology used is known as laser-induced breakdown spectroscopy (LIBS) and possesses several advantages such as speed of operation, ease of use and full compatibility with optical microscopy. We then used two different but complementary approaches to achieve 3D elemental imaging with LIBS: a volume reconstruction of a sliced organ and in-depth analysis. This proof-of-concept study demonstrates the quantitative imaging of both endogenous and exogenous elements within entire organs and paves the way for innumerable applications.
3D Imaging of Nanoparticle Distribution in Biological Tissue by Laser-Induced Breakdown Spectroscopy
NASA Astrophysics Data System (ADS)
Gimenez, Y.; Busser, B.; Trichard, F.; Kulesza, A.; Laurent, J. M.; Zaun, V.; Lux, F.; Benoit, J. M.; Panczer, G.; Dugourd, P.; Tillement, O.; Pelascini, F.; Sancey, L.; Motto-Ros, V.
2016-07-01
Nanomaterials represent a rapidly expanding area of research with huge potential for future medical applications. Nanotechnology indeed promises to revolutionize diagnostics, drug delivery, gene therapy, and many other areas of research. For any biological investigation involving nanomaterials, it is crucial to study the behavior of such nano-objects within tissues to evaluate both their efficacy and their toxicity. Here, we provide the first account of 3D label-free nanoparticle imaging at the entire-organ scale. The technology used is known as laser-induced breakdown spectroscopy (LIBS) and possesses several advantages such as speed of operation, ease of use and full compatibility with optical microscopy. We then used two different but complementary approaches to achieve 3D elemental imaging with LIBS: a volume reconstruction of a sliced organ and in-depth analysis. This proof-of-concept study demonstrates the quantitative imaging of both endogenous and exogenous elements within entire organs and paves the way for innumerable applications.
Regional salt distribution from 3D data across the South Additions, offshore Louisiana
Jamieson, G.A. )
1996-01-01
A contiguous 3D dataset comprising 20 surveys covering over 800 OCS blocks in the offshore Louisiana South Additions region formed the primary database for a regional interpretation of top and base salt surfaces. The interpretation was performed on a 800m by 800m grid of 3D time migrated lines extracted from each survey and loaded into a single project on a workstation. After completing the interpretation the top and base salt horizons were depth converted, incorporating representative well velocity information across the study area. The use of 3D data has significantly improved interpretation confidence, particularly of the base salt, compared to 2D data, which, to date, has been the most commonly utilized regional tool. However, 2D data suffers from out-of-plane effects which can lead to erroneous interpretations of the base of salt and deep welds. A number of significant regional salt-related features and trends have been identified from the top and base salt time and depth maps. Significant identified features on the base of salt and below include keels, welds, fault zones and possible ramps which, in places, display significantly differing trends to those of the suprasalt section. The 3D data allows the mapping of feeders associated with large counter-regional fault systems down to extreme depths, in places to over 7 kms, as well as the location of feeder stock and wall locations beneath salt canopies. This has shown that many large sheets comprise several salt masses which have coalesced along suture zones, for example in the Vermilion and Ship Shoal regions.
Regional salt distribution from 3D data across the South Additions, offshore Louisiana
Jamieson, G.A.
1996-12-31
A contiguous 3D dataset comprising 20 surveys covering over 800 OCS blocks in the offshore Louisiana South Additions region formed the primary database for a regional interpretation of top and base salt surfaces. The interpretation was performed on a 800m by 800m grid of 3D time migrated lines extracted from each survey and loaded into a single project on a workstation. After completing the interpretation the top and base salt horizons were depth converted, incorporating representative well velocity information across the study area. The use of 3D data has significantly improved interpretation confidence, particularly of the base salt, compared to 2D data, which, to date, has been the most commonly utilized regional tool. However, 2D data suffers from out-of-plane effects which can lead to erroneous interpretations of the base of salt and deep welds. A number of significant regional salt-related features and trends have been identified from the top and base salt time and depth maps. Significant identified features on the base of salt and below include keels, welds, fault zones and possible ramps which, in places, display significantly differing trends to those of the suprasalt section. The 3D data allows the mapping of feeders associated with large counter-regional fault systems down to extreme depths, in places to over 7 kms, as well as the location of feeder stock and wall locations beneath salt canopies. This has shown that many large sheets comprise several salt masses which have coalesced along suture zones, for example in the Vermilion and Ship Shoal regions.
NASA Astrophysics Data System (ADS)
Klinger, Carolin; Mayer, Bernhard
2016-01-01
Due to computational costs, radiation is usually neglected or solved in plane parallel 1D approximation in today's numerical weather forecast and cloud resolving models. We present a fast and accurate method to calculate 3D heating and cooling rates in the thermal spectral range that can be used in cloud resolving models. The parameterization considers net fluxes across horizontal box boundaries in addition to the top and bottom boundaries. Since the largest heating and cooling rates occur inside the cloud, close to the cloud edge, the method needs in first approximation only the information if a grid box is at the edge of a cloud or not. Therefore, in order to calculate the heating or cooling rates of a specific grid box, only the directly neighboring columns are used. Our so-called Neighboring Column Approximation (NCA) is an analytical consideration of cloud side effects which can be considered a convolution of a 1D radiative transfer result with a kernel or radius of 1 grid-box (5 pt stencil) and which does usually not break the parallelization of a cloud resolving model. The NCA can be easily applied to any cloud resolving model that includes a 1D radiation scheme. Due to the neglect of horizontal transport of radiation further away than one model column, the NCA works best for model resolutions of about 100 m or lager. In this paper we describe the method and show a set of applications of LES cloud field snap shots. Correction terms, gains and restrictions of the NCA are described. Comprehensive comparisons to the 3D Monte Carlo Model MYSTIC and a 1D solution are shown. In realistic cloud fields, the full 3D simulation with MYSTIC shows cooling rates up to -150 K/d (100 m resolution) while the 1D solution shows maximum coolings of only -100 K/d. The NCA is capable of reproducing the larger 3D cooling rates. The spatial distribution of the heating and cooling is improved considerably. Computational costs are only a factor of 1.5-2 higher compared to a 1D
NASA Astrophysics Data System (ADS)
Godoy, William F.; DesJardin, Paul E.
2010-05-01
The application of flux limiters to the discrete ordinates method (DOM), SN, for radiative transfer calculations is discussed and analyzed for 3D enclosures for cases in which the intensities are strongly coupled to each other such as: radiative equilibrium and scattering media. A Newton-Krylov iterative method (GMRES) solves the final systems of linear equations along with a domain decomposition strategy for parallel computation using message passing libraries in a distributed memory system. Ray effects due to angular discretization and errors due to domain decomposition are minimized until small variations are introduced by these effects in order to focus on the influence of flux limiters on errors due to spatial discretization, known as numerical diffusion, smearing or false scattering. Results are presented for the DOM-integrated quantities such as heat flux, irradiation and emission. A variety of flux limiters are compared to "exact" solutions available in the literature, such as the integral solution of the RTE for pure absorbing-emitting media and isotropic scattering cases and a Monte Carlo solution for a forward scattering case. Additionally, a non-homogeneous 3D enclosure is included to extend the use of flux limiters to more practical cases. The overall balance of convergence, accuracy, speed and stability using flux limiters is shown to be superior compared to step schemes for any test case.
NASA Astrophysics Data System (ADS)
Song, L.; Min, Q.
2012-12-01
Broadband heating directly drives the global atmospheric and oceanic circulation and its vertical profiles strongly depend upon cloud three-dimensional (3D) structures. Due to the complexity of cloud 3D problems and the difficulties in observations of broadband heating rate profiles (BBHRP), there are still large uncertainties in the relationship of clouds, radiation and climate feedback. Oxygen A-band photon pathlength distributions (PPLD) contain rich information about the 3D structures of clouds and BBHRP and can be observed by both ground based and space based measurements. Therefore, it is meaningful to explore the possibility of connecting A-band PPLD and BBHRP and consequently to describe the internal relationship between them together with the cloud 3D effects on BBHRP. A 3D Monte Carlo radiative transfer model is applied to simulate solar broadband heating rate profiles and oxygen A-band photon pathlength distributions of several ideal cloud fields and two typical cloud fields generated by cloud resolving model (CRM). Principal components (PCs) and the first four moments are selected to represent the vertical structures of BBHRP and PPLD, respectively. In ideal cloud fields, the moments show clear constraint to PCs of BBHRP. The results demonstrate the feasibility to describe the vertical structures of BBHRP by PPLD. The relationship between moments and PCs turns complicated in CRM cloud fields due to the composition of various 3D effects. However, detailed analysis still show that the moments, the PCs and total cloud optical depth are effective factors in defining BBHRP, especially for the vertical structures of relative low clouds. Further, a statistical fitting between the PCs and the moments by a two-layer neural network is applied to provide a quantitative representation of the linkages.
The prediction of transmitted dose distributions using a 3D treatment planning system.
Reich, P; Bezak, E; Mohammadi, M; Fog, L
2006-03-01
Patient dose verification is becoming increasingly important with the advent of new complex radiotherapy techniques such as conformal radiotherapy (CRT) and intensity-modulated radiotherapy (IMRT). An electronic portal imaging device (EPID) has potential application for in vivo dosimetry. In the current work, an EPID has been modelled using a treatment planning system (TPS) to predict transmitted dose maps. A thin slab of RW3 material used to initially represent the EPID. A homogeneous RW3 phantom and the thin RW3 slab placed at a clinical distance away from the phantom were scanned using a CT simulator. The resulting CT images were transferred via DICOM to the TPS and the density of the CT data corresponding to the thin RW3 slab was changed to 1 g/cm3. Transmitted dose maps (TDMs) in the modelled EPID were calculated by the TPS using the collapsed-cone (C-C) convolution superposition (C/S) algorithm. A 6 MV beam was used in the simulation to deliver 300 MU to the homogenous phantom using an isocentric and SSD (source-to-surface) technique. The phantom thickness was varied and the calculated TDMs in the modelled EPID were compared with corresponding measurements obtained from a calibrated scanning liquid-filled ionisation chamber (SLIC) EPID. The two TDMs were compared using the gamma evaluation technique of Low et al. The predicted and measured TDMs agree to within 2 % (averaged over all phantom thicknesses) on the central beam axis. More than 90 % of points in the dose maps (excluding field edges) produce a gamma index less than or equal to 1, for dose difference (averaged over all phantom thicknesses), and distance-to-agreement criteria of 4 %, 3.8 mm, respectively. In addition, the noise level on the central axis in the predicted dose maps is less than 0.1 %. We found that phantom thickness changes of approximately 1 mm, which correspond to dose changes on the central beam axis of less than 0.6 %, can be detected in the predicted transmitted dose distributions.
Gamma Knife 3-D dose distribution near the area of tissue inhomogeneities by normoxic gel dosimetry
Isbakan, Fatih; Uelgen, Yekta; Bilge, Hatice; Ozen, Zeynep; Agus, Onur; Buyuksarac, Bora
2007-05-15
The accuracy of the Leksell GammaPlan registered , the dose planning system of the Gamma Knife Model-B, was evaluated near tissue inhomogeneities, using the gel dosimetry method. The lack of electronic equilibrium around the small-diameter gamma beams can cause dose calculation errors in the neighborhood of an air-tissue interface. An experiment was designed to investigate the effects of inhomogeneity near the paranosal sinuses cavities. The homogeneous phantom was a spherical glass balloon of 16 cm diameter, filled with MAGIC gel; i.e., the normoxic polymer gel. Two hollow PVC balls of 2 cm radius, filled with N{sub 2} gas, represented the air cavities inside the inhomogeneous phantom. For dose calibration purposes, 100 ml gel-containing vials were irradiated at predefined doses, and then scanned in a MR unit. Linearity was observed between the delivered dose and the reciprocal of the T2 relaxation time constant of the gel. Dose distributions are the results of a single shot of irradiation, obtained by collimating all 201 cobalt sources to a known target in the phantom. Both phantoms were irradiated at the same dose level at the same coordinates. Stereotactic frames and fiducial markers were attached to the phantoms prior to MR scanning. The dose distribution predicted by the Gamma Knife planning system was compared with that of the gel dosimetry. As expected, for the homogeneous phantom the isodose diameters measured by the gel dosimetry and the GammaPlan registered differed by 5% at most. However, with the inhomogeneous phantom, the dose maps in the axial, coronal and sagittal planes were spatially different. The diameters of the 50% isodose curves differed 43% in the X axis and 32% in the Y axis for the Z=90 mm axial plane; by 44% in the X axis and 24% in the Z axis for the Y=90 mm coronal plane; and by 32% in the Z axis and 42% in the Y axis for the X=92 mm sagittal plane. The lack of ability of the GammaPlan registered to predict the rapid dose fall off, due
3D Imaging of Nanoparticle Distribution in Biological Tissue by Laser-Induced Breakdown Spectroscopy
Gimenez, Y.; Busser, B.; Trichard, F.; Kulesza, A.; Laurent, J. M.; Zaun, V.; Lux, F.; Benoit, J. M.; Panczer, G.; Dugourd, P.; Tillement, O.; Pelascini, F.; Sancey, L.; Motto-Ros, V.
2016-01-01
Nanomaterials represent a rapidly expanding area of research with huge potential for future medical applications. Nanotechnology indeed promises to revolutionize diagnostics, drug delivery, gene therapy, and many other areas of research. For any biological investigation involving nanomaterials, it is crucial to study the behavior of such nano-objects within tissues to evaluate both their efficacy and their toxicity. Here, we provide the first account of 3D label-free nanoparticle imaging at the entire-organ scale. The technology used is known as laser-induced breakdown spectroscopy (LIBS) and possesses several advantages such as speed of operation, ease of use and full compatibility with optical microscopy. We then used two different but complementary approaches to achieve 3D elemental imaging with LIBS: a volume reconstruction of a sliced organ and in-depth analysis. This proof-of-concept study demonstrates the quantitative imaging of both endogenous and exogenous elements within entire organs and paves the way for innumerable applications. PMID:27435424
Salt distribution in the Louisiana South Additions area from 3D seismic data
Jamieson, G.A.
1996-12-31
This paper outlines some preliminary observations based on a large interpretation project that was carried out with a grid of 3D time migrated seismic data, covering over 7,500 mi{sup 2} of the South Additions region of offshore Louisiana. Depth migrated data, covering a smaller subset of the study area, was also utilized in the interpretation. Top and base of salt were interpreted and the resulting maps have identified patterns of salt and weld geometry that show some regional trends. Historically, 2D time migrated seismic has been the primary dataset of most of the published regional salt studies. This paper focuses on areas where 3D time migrated data potentially shows most improvement over 2D data, specifically in the subsalt regions. In particular, relationships between base-of-salt keels, welds, basins, regional faulting and basement architecture are investigated. A generalized model is outlined to help explain the current salt geometry in the study area and comparisons are made with recently published salt evolution models.
NASA Astrophysics Data System (ADS)
Gerke, H. H.; Schneider, A.; Maurer, T.; Raab, T. A.
2009-12-01
For systems such as soils or watersheds, the initial distribution of sediment mass and composition at the starting point of the development are mostly not well-known. The development of such systems, however, has frequently been assumed to depend on boundary and initial conditions including the solid phase. Here, an experimental watershed of about 6 ha surface area was artificially-created in order to imitate an initial stage just at the beginning of the geo-ecosystem development. However, sediment homogeneity could not be achieved for this large-scale field experiment, and the 3D spatial distribution of structures and components remained uncertain. The objective of this study was to quantify and reconstruct the initial sediment distribution and the first development stages using aerial photographs, point information, and a 3D model. The watershed was made of coarse-textured sediments of quaternary origin with a low permeable clay liner as the bottom boundary. A 2D horizontal digital elevation model (DEM) of the surface and a DEM of the subsurface clay layer are used to construct a 3D triangulated numerical grid of the catchment’s initial spatial structure using the 3D-GIS software GOCAD. Physical and chemical soil properties obtained from borehole samples are assigned to this model and interpolated onto the 3D grid. The volumetric changes in space and time are quantified and related to material properties to obtain the mass changes. Correlations between terrain attributes, sediment properties, and mass changes are explored specifically in regions of differing source materials. A temporal sequence of surface DEMs is obtained from photogrammetric, high-precision ground based laser scanning and airborne laser scanning data. 3D models of elevation change are constructed from these DEMs. The processes following the initial state are mainly characterized by runoff-induced erosive mass relocations related to the distribution of surface and subsurface structures and
Low-cost real-time 3D PC distributed-interactive-simulation (DIS) application for C4I
NASA Astrophysics Data System (ADS)
Gonthier, David L.; Veron, Harry
1998-04-01
A 3D Distributed Interactive Simulation (DIS) application was developed and demonstrated in a PC environment. The application is capable of running in the stealth mode or as a player which includes battlefield simulations, such as ModSAF. PCs can be clustered together, but not necessarily collocated, to run a simulation or training exercise on their own. A 3D perspective view of the battlefield is displayed that includes terrain, trees, buildings and other objects supported by the DIS application. Screen update rates of 15 to 20 frames per second have been achieved with fully lit and textured scenes thus providing high quality and fast graphics. A complete PC system can be configured for under $2,500. The software runs under Windows95 and WindowsNT. It is written in C++ and uses a commercial API called RenderWare for 3D rendering. The software uses Microsoft Foundation classes and Microsoft DirectPlay for joystick input. The RenderWare libraries enhance the performance through optimization for MMX and the Pentium Pro processor. The RenderWare and the Righteous 3D graphics board from Orchid Technologies with an advertised rendering rate of up to 2 million texture mapped triangles per second. A low-cost PC DIS simulator that can partake in a real-time collaborative simulation with other platforms is thus achieved.
NASA Astrophysics Data System (ADS)
Lopez-Sanchez, Marco; Llana-Fúnez, Sergio
2016-04-01
The understanding of creep behaviour in rocks requires knowledge of 3D grain size distributions (GSD) that result from dynamic recrystallization processes during deformation. The methods to estimate directly the 3D grain size distribution -serial sectioning, synchrotron or X-ray-based tomography- are expensive, time-consuming and, in most cases and at best, challenging. This means that in practice grain size distributions are mostly derived from 2D sections. Although there are a number of methods in the literature to derive the actual 3D grain size distributions from 2D sections, the most popular in highly deformed rocks is the so-called Saltykov method. It has though two major drawbacks: the method assumes no interaction between grains, which is not true in the case of recrystallised mylonites; and uses histograms to describe distributions, which limits the quantification of the GSD. The first aim of this contribution is to test whether the interaction between grains in mylonites, i.e. random grain packing, affects significantly the GSDs estimated by the Saltykov method. We test this using the random resampling technique in a large data set (n = 12298). The full data set is built from several parallel thin sections that cut a completely dynamically recrystallized quartz aggregate in a rock sample from a Variscan shear zone in NW Spain. The results proved that the Saltykov method is reliable as long as the number of grains is large (n > 1000). Assuming that a lognormal distribution is an optimal approximation for the GSD in a completely dynamically recrystallized rock, we introduce an additional step to the Saltykov method, which allows estimating a continuous probability distribution function of the 3D grain size population. The additional step takes the midpoints of the classes obtained by the Saltykov method and fits a lognormal distribution with a trust region using a non-linear least squares algorithm. The new protocol is named the two-step method. The
Osewski, Wojciech; Dolla, Łukasz; Radwan, Michał; Szlag, Marta; Rutkowski, Roman; Smolińska, Barbara; Ślosarek, Krzysztof
2014-01-01
Aim To present practical examples of our new algorithm for reconstruction of 3D dose distribution, based on the actual MLC leaf movement. Background DynaLog and RTplan files were used by DDcon software to prepare a new RTplan file for dose distribution reconstruction. Materials and methods Four different clinically relevant scenarios were used to assess the feasibility of the proposed new approach: (1) Reconstruction of whole treatment sessions for prostate cancer; (2) Reconstruction of IMRT verification treatment plan; (3) Dose reconstruction in breast cancer; (4) Reconstruction of interrupted arc and complementary plan for an interrupted VMAT treatment session of prostate cancer. The applied reconstruction method was validated by comparing reconstructed and measured fluence maps. For all statistical analysis, the U Mann–Whitney test was used. Results In the first two and the fourth cases, there were no statistically significant differences between the planned and reconstructed dose distribution (p = 0.910, p = 0.975, p = 0.893, respectively). In the third case the differences were statistically significant (p = 0.015). Treatment plan had to be reconstructed. Conclusion Developed dose distribution reconstruction algorithm presents a very useful QA tool. It provides means for 3D dose distribution verification in patient volume and allows to evaluate the influence of actual MLC leaf motion on the dose distribution. PMID:25337416
Inhaled Aerosol Distribution in Human Airways: A Scintigraphy-Guided Study in a 3D Printed Model.
Verbanck, Sylvia; Ghorbaniasl, Ghader; Biddiscombe, Martyn F; Dragojlovic, Dusica; Ricks, Nathan; Lacor, Chris; Ilsen, Bart; de Mey, Johan; Schuermans, Daniel; Underwood, S Richard; Barnes, Peter J; Vincken, Walter; Usmani, Omar S
2016-12-01
While it is generally accepted that inertial impaction will lead to particle loss as aerosol is being carried into the pulmonary airways, most predictive aerosol deposition models adopt the hypothesis that the inhaled particles that remain airborne will distribute according to the gas flow distribution between airways downstream. Using a 3D printed cast of human airways, we quantified particle deposition and distribution and visualized their inhaled trajectory in the human lung. The human airway cast was exposed to 6 μm monodisperse, radiolabeled aerosol particles at distinct inhaled flow rates and imaged by scintigraphy in two perpendicular planes. In addition, we also imaged the distribution of aerosol beyond the airways into the five lung lobes. The experimental aerosol deposition patterns could be mimicked by computational fluid dynamic (CFD) simulation in the same 3D airway geometry. It was shown that for particles with a diameter of 6 μm inhaled at flows up to 60 L/min, the aerosol distribution over both lungs and the individual five lung lobes roughly followed the corresponding distributions of gas flow. While aerosol deposition was greater in the main bronchi of the left versus right lung, distribution of deposited and suspended particles toward the right lung exceeded that of the left lung. The CFD simulations also predict that for both 3 and 6 μm particles, aerosol distribution between lung units subtending from airways in generation 5 did not match gas distribution between these units and that this effect was driven by inertial impaction. We showed combined imaging experiments and CFD simulations to systematically study aerosol deposition patterns in human airways down to generation 5, where particle deposition could be spatially linked to the airway geometry. As particles are negotiating an increasing number of airways in subsequent branching generations, CFD predicts marked deviations of aerosol distribution with respect to ventilation
Exterior 3D lamb problem: Harmonic load distributed over a surface
NASA Astrophysics Data System (ADS)
Il'yasov, Kh. Kh.; Kravtsov, A. V.; Kuznetsov, S. V.; Sekerzh-Zen'kovich, S. Ya.
2016-06-01
The solutions of the exterior Lamb problem with a distributed harmonic surface load acting on the boundary of an elastic half-space are studied. A load normal to the surface and distributed over the surface as the Poisson kernel is considered. The solution is constructed with the use of integral transforms and the finite-element method.
1994-09-01
GENERAL GEOMETRY PIC SOFTWARE FOR DISTRIBUTED MEMORY MIMD COMPUTERS : TASK 1 FINAL REPORT J W Eastwood, W... GENERAL GEOMETRY PIC SOFTWARE FOR DISTRIBUTED MEMORY MIMD COMPUTERS : TASK 1 FINAL REPORT J W Eastwood, W Arter, N J Brealey, R W Hockney September 1994... General geometry PIC for MIMD computers : Final report . Report RFFX(93)56,
Chin, Yong Ho; Kim, Kwang-Je; Xie, Ming.
1992-08-01
In the previous paper, we have derived a dispersion relation for the free electron laser (FEL) gain in the exponential regime taking account the diffraction and electron's betatron oscillation. Here, we compare the growth rates obtained by solving the dispersion relation with those obtained by simulation calculation for the waterbag and the Gaussian models for the electron's transverse phase space distribution. The agreement is found to be good except for the limiting case where the Rayleigh length is much longer than the gain length (1-D limit). We also generalize the analysis to the case where the electron beam cross section is elliptical as is usually the case in storage rings, and derive the first-order dispersion relation.
Chin, Yong Ho; Kim, Kwang-Je; Xie, Ming
1992-08-01
In the previous paper, we have derived a dispersion relation for the free electron laser (FEL) gain in the exponential regime taking account the diffraction and electron`s betatron oscillation. Here, we compare the growth rates obtained by solving the dispersion relation with those obtained by simulation calculation for the waterbag and the Gaussian models for the electron`s transverse phase space distribution. The agreement is found to be good except for the limiting case where the Rayleigh length is much longer than the gain length (1-D limit). We also generalize the analysis to the case where the electron beam cross section is elliptical as is usually the case in storage rings, and derive the first-order dispersion relation.
NASA Astrophysics Data System (ADS)
Srinivasan, V.; Yiwen, X.; Ellis, A.; Christensen, A.; Borkiewic, K.; Cox, D.; Hart, J.; Long, S.; Marshall-Colon, A.
2016-12-01
The distribution of absorbed solar radiation in the photosynthetically active region wavelength (PAR) within plant canopies plays a critical role in determining photosynthetic carbon uptake and its associated transpiration. The vertical distribution of leaf area, leaf angles, leaf absorptivity and reflectivity within the canopy, affect the distribution of PAR absorbed throughout the canopy. While the upper canopy sunlit leaves absorb most of the incoming PAR and hence contribute most towards total canopy carbon uptake, the lower canopy shaded leaves which receive mostly lower intensity diffuse PAR make significant contributions towards plant carbon uptake. Most detailed vegetation models use a 1-D vertical multi-layer approach to model the sunlight and shaded canopy leaf fractions, and quantify the direct and diffuse radiation absorbed by the respective leaf fractions. However, this approach is only applicable under canopy closure conditions, and furthermore it fails to accurately capture the effects of diurnally varying leaf angle distributions in some plant canopies. Here, we show by using a 3-D ray tracing model which uses an explicit 3-D canopy structure that enforces no conditions about canopy closure, that the effects of diurnal variation of canopy leaf angle distributions better match with observed data. Our comparative analysis performed on soybean crop canopies between 3-D ray tracing model and the multi-layer model shows that the distribution of absorbed direct PAR is not exponential while, the distribution of absorbed diffuse PAR radiation within plant canopies is exponential. These results show the multi-layer model to significantly over-predict canopy PAR absorbed, and in turn significantly overestimate photosynthetic carbon uptake by up to 13% and canopy transpiration by 7% under mid-day sun conditions as verified through our canopy chamber experiments. Our results indicate that current detailed 1-D multi-layer canopy radiation attenuation models
NASA Astrophysics Data System (ADS)
Maurer, T.; Bartsch, R.; Schneider, A.; Gerke, H. H.
2012-04-01
Modelling the spatial heterogeneity of catchments is a prerequisite for the understanding of flow processes and the application of hydrological models. The initial structure represents also the starting point for catchment and ecosystem development. The quality of hydrologic modeling is often limited due to a lack of data or an oversimplification of aquifer properties. Predictions can be significantly improved by using spatial models that reproduce specific structural characteristics. Current geostatistical methods are unable the capture spatially complex conditions, e.g. abrupt changes in structures. More deterministic structure generator approaches are currently been discussed in hydrogeology for exploration. Process-based structure generators deduce structural characteristics e.g. from the known formation processes of the aquifer. The objective was to describe the spatial distribution of soil hydraulic properties in a catchment based on generated 3D sediments distributions. The approach was tested for the artificially constructed "Hühnerwasser" ("Chicken Creek") catchment. The catchment is located in the post-lignite mining area of Welzow-Süd in Lower Lusatia, Brandenburg, Germany. Here, the initial sediment distribution was governed primarily by dumping processes of the large-scale mining technology and the geological conditions at the excavation site. For the initially organic matter-free sandy sediments, the structure model generated the distributions of soil texture and soil bulk density within dumping spoil cones. These were represented by 2D cross sections with compacted central parts and particle-segregated flanks. The 3D geometry of the catchment was generated by sequencing of these basic structural elements along identified stacker trajectories, finally yielding a discretized 3D volume model using the GOCAD software. Based on these data, spatial distributions of hydraulic properties were calculated using well-established pedotransfer functions
NASA Astrophysics Data System (ADS)
Ma, S.; Yan, W.; Xu, L.
2013-12-01
The quantitative retrieval of the 3-D spatial distribution of the parent energetic ions of ENA from a 2-D ENA image is a quite challenge task. The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission of NASA is the first constellation to perform stereoscopic magnetospheric imaging of energetic neutral atoms (ENA) from a pair of spacecraft flying on two widely-separated Molniya orbits. TWINS provides a unique opportunity to retrieve the 3-D distribution of ions in the ring current (RC) by using a volumetric pixel (voxel) CT inversion method. In this study the voxel CT method is implemented for a series of differential ENA fluxes averaged over about 6 to 7 sweeps (corresponding to a time period of about 9 min.) at different energy levels ranging from 5 to 100 keV, obtained simultaneously by the two satellites during the main phase of a great magnetic storm with minimum Sym-H of -156 nT on 24-25 October 2011. The data were selected to span a period about 50 minutes during which a large substorm was undergoing its expansion phase first and then recovery. The ENA species of O and H are distinguished for some time-segments by analyzing the signals of pulse heights of second electrons emitted from the carbon foil and impacted on the MCP detector in the TWINS sensors. In order to eliminate the possible influence on retrieval induced by instrument bias error, a differential voxel CT technique is applied. The flux intensity of the ENAs' parent ions in the RC has been obtained as a function of energy, L value, MLT sector and latitude, along with their time evolution during the storm-time substorm expansion phase. Forward calculations proved the reliability of the retrieved results. It shows that the RC is highly asymmetric, with a major concentration in the midnight to dawn sector for equatorial latitudes. Halfway through the substorm expansion there occurred a large enhancement of equatorial ion flux at lower energy (5 keV) in the dusk sector, with narrow extent
Novel methods for estimating 3D distributions of radioactive isotopes in materials
NASA Astrophysics Data System (ADS)
Iwamoto, Y.; Kataoka, J.; Kishimoto, A.; Nishiyama, T.; Taya, T.; Okochi, H.; Ogata, H.; Yamamoto, S.
2016-09-01
In recent years, various gamma-ray visualization techniques, or gamma cameras, have been proposed. These techniques are extremely effective for identifying "hot spots" or regions where radioactive isotopes are accumulated. Examples of such would be nuclear-disaster-affected areas such as Fukushima or the vicinity of nuclear reactors. However, the images acquired with a gamma camera do not include distance information between radioactive isotopes and the camera, and hence are "degenerated" in the direction of the isotopes. Moreover, depth information in the images is lost when the isotopes are embedded in materials, such as water, sand, and concrete. Here, we propose two methods of obtaining depth information of radioactive isotopes embedded in materials by comparing (1) their spectra and (2) images of incident gamma rays scattered by the materials and direct gamma rays. In the first method, the spectra of radioactive isotopes and the ratios of scattered to direct gamma rays are obtained. We verify experimentally that the ratio increases with increasing depth, as predicted by simulations. Although the method using energy spectra has been studied for a long time, an advantage of our method is the use of low-energy (50-150 keV) photons as scattered gamma rays. In the second method, the spatial extent of images obtained for direct and scattered gamma rays is compared. By performing detailed Monte Carlo simulations using Geant4, we verify that the spatial extent of the position where gamma rays are scattered increases with increasing depth. To demonstrate this, we are developing various gamma cameras to compare low-energy (scattered) gamma-ray images with fully photo-absorbed gamma-ray images. We also demonstrate that the 3D reconstruction of isotopes/hotspots is possible with our proposed methods. These methods have potential applications in the medical fields, and in severe environments such as the nuclear-disaster-affected areas in Fukushima.
Automated quantitative 3D analysis of aorta size, morphology, and mural calcification distributions
Kurugol, Sila Come, Carolyn E.; Diaz, Alejandro A.; Ross, James C.; Washko, George R.; San Jose Estepar, Raul; Kinney, Greg L.; Black-Shinn, Jennifer L.; Hokanson, John E.; Budoff, Matthew J.
2015-09-15
Purpose: The purpose of this work is to develop a fully automated pipeline to compute aorta morphology and calcification measures in large cohorts of CT scans that can be used to investigate the potential of these measures as imaging biomarkers of cardiovascular disease. Methods: The first step of the automated pipeline is aorta segmentation. The algorithm the authors propose first detects an initial aorta boundary by exploiting cross-sectional circularity of aorta in axial slices and aortic arch in reformatted oblique slices. This boundary is then refined by a 3D level-set segmentation that evolves the boundary to the location of nearby edges. The authors then detect the aortic calcifications with thresholding and filter out the false positive regions due to nearby high intensity structures based on their anatomical location. The authors extract the centerline and oblique cross sections of the segmented aortas and compute the aorta morphology and calcification measures of the first 2500 subjects from COPDGene study. These measures include volume and number of calcified plaques and measures of vessel morphology such as average cross-sectional area, tortuosity, and arch width. Results: The authors computed the agreement between the algorithm and expert segmentations on 45 CT scans and obtained a closest point mean error of 0.62 ± 0.09 mm and a Dice coefficient of 0.92 ± 0.01. The calcification detection algorithm resulted in an improved true positive detection rate of 0.96 compared to previous work. The measurements of aorta size agreed with the measurements reported in previous work. The initial results showed associations of aorta morphology with calcification and with aging. These results may indicate aorta stiffening and unwrapping with calcification and aging. Conclusions: The authors have developed an objective tool to assess aorta morphology and aortic calcium plaques on CT scans that may be used to provide information about the presence of cardiovascular
NASA Astrophysics Data System (ADS)
Ponomaryov, Semyon S.; Yukhymchuk, Volodymyr O.; Lytvyn, Peter M.; Valakh, Mykhailo Ya
2016-02-01
An application of scanning Auger microscopy with ion etching technique and effective compensation of thermal drift of the surface analyzed area is proposed for direct local study of composition distribution in the bulk of single nanoislands. For GexSi1 - x-nanoislands obtained by MBE of Ge on Si-substrate gigantic interdiffusion mixing takes place both in the open and capped nanostructures. Lateral distributions of the elemental composition as well as concentration-depth profiles were recorded. 3D distribution of the elemental composition in the d-cluster bulk was obtained using the interpolation approach by lateral composition distributions in its several cross sections and concentration-depth profile. It was shown that there is a germanium core in the nanoislands of both nanostructure types, which even penetrates the substrate. In studied nanostructures maximal Ge content in the nanoislands may reach about 40 at.%.
Intensifying the response of distributed optical fibre sensors using 2D and 3D image restoration
Soto, Marcelo A.; Ramírez, Jaime A.; Thévenaz, Luc
2016-01-01
Distributed optical fibre sensors possess the unique capability of measuring the spatial and temporal map of environmental quantities that can be of great interest for several field applications. Although existing methods for performance enhancement have enabled important progresses in the field, they do not take full advantage of all information present in the measured data, still giving room for substantial improvement over the state-of-the-art. Here we propose and experimentally demonstrate an approach for performance enhancement that exploits the high level of similitude and redundancy contained on the multidimensional information measured by distributed fibre sensors. Exploiting conventional image and video processing, an unprecedented boost in signal-to-noise ratio and measurement contrast is experimentally demonstrated. The method can be applied to any white-noise-limited distributed fibre sensor and can remarkably provide a 100-fold improvement in the sensor performance with no hardware modification. PMID:26927698
Calculated angular distributions of energetic atmospheric neutrons
NASA Technical Reports Server (NTRS)
Merker, M.
1975-01-01
Calculated angular distributions of atmospheric leakage neutron fluxes from 19 MeV to 1 GeV are presented. Comparisons with the balloon measurements of Preszler et al. and Kanbach et al. are made and show substantial agreement, strengthening the belief in the importance of the CRAND (cosmic-ray albedo-neutron decay) contribution to the high-energy protons in the earth's inner radiation belt. The calculation is presented as a means for investigating features of atmospheric flux distributions.
Verification of 3D Dose Distributions of a Beta-Emitting Radionuclide Using PRESAGE^ Dosimeters
NASA Astrophysics Data System (ADS)
Crowder, Mandi; Grant, Ryan; Ibbott, Geoff; Wendt, Richard
2010-11-01
Liquid Brachytherapy involves the direct administration of a beta-emitting radioactive solution into the selected tissue. The solution does not migrate from the injection point and uses the limited range of beta particles to produce a three-dimensional dose distribution. We simulated distributions by beta-dose kernels and validated those estimates by irradiating PRESAGE^ polyurethane dosimeters that measure the three-dimensional dose distributions by a change in optical density that is proportional to dose. The dosimeters were injected with internal beta-emitting radionuclide yttrium-90, exposed for 5.75 days, imaged with optical tomography, and analyzed with radiotherapy software. Dosimeters irradiated with an electron beam to 2 or 3 Gy were used for calibration. The shapes and dose distributions in the PRESAGE^ dosimeters were consistent with the predicted dose kernels. Our experiments have laid the groundwork for future application to individualized patient therapy by ultimately designing a treatment plan that conforms to the shape of any appropriate tumor.
Localised vs distributed deformation: 3D modelling of the Dead Sea region
NASA Astrophysics Data System (ADS)
Devès, M. H.; King, G. C.; Klinger, Y.; Agnon, A.
2012-12-01
The lithosphere behaves as strain softening elasto-plastic materials. In the laboratory, such materials are known to deform in a brittle or a ductile manner depending on the applied geometric boundary conditions. In the lithosphere however, the importance of boundary conditions in controlling the deformation style has been largely ignored. Under general boundary conditions, both laboratory and field observations show that only part of the deformation can localise on through going faults while the rest must remain distributed in process zones where spatially varying shear directions inhibit localisation. Conventional modelling methods use rheologies deduced from laboratory experiments that are not constrained as a function of the geometry of the applied boundary conditions. We propose an alternative modelling method based on the use of an appropriate distribution of dislocation sources to create the deformation field. This approach, because it does not rely on integrating differential equations from more or less well-constrained boundary conditions, does not require making assumptions on the parameters controlling the level and distribution of stresses within the lithosphere. It only supposes that strain accumulates linearly away from the dislocation singularities satisfying the compatibility equations. We verify that this model explains important and hitherto unexplained features of the topography of the Dead Sea region. Following the idea that strain can only localise under specific conditions as inferred from laboratory and field scale observations, we use our model of deformation to predict where deformation can localise and where it has to remain distributed. We find that 65% of the deformation in the Dead Sea region can localise on kinematically stable through-going strike-slip faults while the remaining 35% must remain distributed. Observations suggest that distributed deformation occurs at stress levels that can be ten times greater than that associated with
NASA Astrophysics Data System (ADS)
Bogena, H. R.; Sciuto, G.; Rosenbaum, U.; Herbst, M.; Huisman, J. A.; Vereecken, H.; Diekkrueger, B.
2010-12-01
Hydrological analysis is often limited by the number of data available. Usually, discharge data and only little point information concerning soil moisture status are available. This might give a good representation of the temporal variability of runoff, but it does not provide insights into the spatial dynamics of soil moisture and water fluxes within the catchment. The small forested Wüstebach catchment (~27 ha) has been instrumented with a wireless sensor network consisting of 150 nodes and more than 1200 soil moisture sensors in the framework of the Transregio32 and the Helmholtz initiative TERENO (Terrestrial Environmental Observatories) [1]. This unique data set provides a consistent picture of the hydrological status of the catchment in a high spatial and temporal resolution. We present first results of a geostatistical analysis of the data and an application of the integrated surface/subsurface 3D finite element model HydroGeoSphere model to investigate the scale dependency of the temporal dynamics of soil moisture patterns. A variogram analysis showed that the sum of the sub-scale variability and the measurement error is close to time-invariant. Wet situations showed smaller spatial variability, which is attributed to saturated soil moisture, which poses an upper limit and is typically not strongly variable in headwater catchments with relatively homogeneous soil. The spatiotemporal variability in soil moisture at 50 cm depth was significantly lower than at 5 and 20 cm. This finding indicates that the considerable variability of the top soil is buffered deeper in the soil due to root water uptake, lateral and vertical water fluxes. Topographic features showed the strongest correlation with soil moisture during dry periods, indicating that the control of topography on the soil moisture pattern depends on the soil water status. The temporal patterns of runoff discharge were reproduced by the HydroGeoSphere model in a satisfying way. The observed soil
Calculation of Dose Deposition in 3D Voxels by Heavy Ions and Simulation of gamma-H2AX Experiments
NASA Technical Reports Server (NTRS)
Plante, I.; Ponomarev, A. L.; Wang, M.; Cucinotta, F. A.
2011-01-01
The biological response to high-LET radiation is different from low-LET radiation due to several factors, notably difference in energy deposition and formation of radiolytic species. Of particular importance in radiobiology is the formation of double-strand breaks (DSB), which can be detected by -H2AX foci experiments. These experiments has revealed important differences in the spatial distribution of DSB induced by low- and high-LET radiations [1,2]. To simulate -H2AX experiments, models based on amorphous track with radial dose are often combined with random walk chromosome models [3,4]. In this work, a new approach using the Monte-Carlo track structure code RITRACKS [5] and chromosome models have been used to simulate DSB formation. At first, RITRACKS have been used to simulate the irradiation of a cubic volume of 5 m by 1) 450 1H+ ions of 300 MeV (LET 0.3 keV/ m) and 2) by 1 56Fe26+ ion of 1 GeV/amu (LET 150 keV/ m). All energy deposition events are recorded to calculate dose in voxels of 20 m. The dose voxels are distributed randomly and scattered uniformly within the volume irradiated by low-LET radiation. Many differences are found in the spatial distribution of dose voxels for the 56Fe26+ ion. The track structure can be distinguished, and voxels with very high dose are found in the region corresponding to the track "core". These high-dose voxels are not found in the low-LET irradiation simulation and indicate clustered energy deposition, which may be responsible for complex DSB. In the second step, assuming that DSB will be found only in voxels where energy is deposited by the radiation, the intersection points between voxels with dose > 0 and simulated chromosomes were obtained. The spatial distribution of the intersection points is similar to -H2AX foci experiments. These preliminary results suggest that combining stochastic track structure and chromosome models could be a good approach to understand radiation-induced DSB and chromosome aberrations.
Calculation of the Poisson cumulative distribution function
NASA Technical Reports Server (NTRS)
Bowerman, Paul N.; Nolty, Robert G.; Scheuer, Ernest M.
1990-01-01
A method for calculating the Poisson cdf (cumulative distribution function) is presented. The method avoids computer underflow and overflow during the process. The computer program uses this technique to calculate the Poisson cdf for arbitrary inputs. An algorithm that determines the Poisson parameter required to yield a specified value of the cdf is presented.
Mapping motion from 4D-MRI to 3D-CT for use in 4D dose calculations: A technical feasibility study
Boye, Dirk; Lomax, Tony; Knopf, Antje
2013-06-15
Purpose: Target sites affected by organ motion require a time resolved (4D) dose calculation. Typical 4D dose calculations use 4D-CT as a basis. Unfortunately, 4D-CT images have the disadvantage of being a 'snap-shot' of the motion during acquisition and of assuming regularity of breathing. In addition, 4D-CT acquisitions involve a substantial additional dose burden to the patient making many, repeated 4D-CT acquisitions undesirable. Here the authors test the feasibility of an alternative approach to generate patient specific 4D-CT data sets. Methods: In this approach motion information is extracted from 4D-MRI. Simulated 4D-CT data sets [which the authors call 4D-CT(MRI)] are created by warping extracted deformation fields to a static 3D-CT data set. The employment of 4D-MRI sequences for this has the advantage that no assumptions on breathing regularity are made, irregularities in breathing can be studied and, if necessary, many repeat imaging studies (and consequently simulated 4D-CT data sets) can be performed on patients and/or volunteers. The accuracy of 4D-CT(MRI)s has been validated by 4D proton dose calculations. Our 4D dose algorithm takes into account displacements as well as deformations on the originating 4D-CT/4D-CT(MRI) by calculating the dose of each pencil beam based on an individual time stamp of when that pencil beam is applied. According to corresponding displacement and density-variation-maps the position and the water equivalent range of the dose grid points is adjusted at each time instance. Results: 4D dose distributions, using 4D-CT(MRI) data sets as input were compared to results based on a reference conventional 4D-CT data set capturing similar motion characteristics. Almost identical 4D dose distributions could be achieved, even though scanned proton beams are very sensitive to small differences in the patient geometry. In addition, 4D dose calculations have been performed on the same patient, but using 4D-CT(MRI) data sets based on
Calculation of the virtual current in an electromagnetic flow meter with one bubble using 3D model.
Zhang, Xiao-Zhang; Li, Yantao
2004-04-01
Based on the theory of electromagnetic induction flow measurement, the Laplace equation in a complicated three-dimensional (3D) domain is solved by an alternating method. Virtual current potentials are obtained for an electromagnetic flow meter with one spherical bubble inside. The solutions are used to investigate the effects of bubble size and bubble position on the virtual current. Comparisons are done among the cases of 2D and 3D models, and of point electrode and large electrode. The results show that the 2D model overestimates the effect, while large electrodes are least sensitive to the bubble. This paper offers fundamentals for the study of the behavior of an electromagnetic flow meter in multiphase flow. For application, the results provide a possible way to estimate errors of the flow meter caused by multiphase flow.
Parallel computation of the SAR distribution in a 3D human head model
NASA Astrophysics Data System (ADS)
Walendziuk, Wojciech
2008-01-01
This work presents a way of parallel computation of the Specific Absorption Rate distribution. The parallel program used in the computation was based on the FDTD (Finite-Difference Time-Domain) method [1,2,3]. In order to establish communication among the computational nodes, the MPI (Message Passing Interface) standard was used [4,5,6]. The presented example of a human head numerical model was built with the use of MRI (Magnetic Resonance Image) pictures.
NASA Astrophysics Data System (ADS)
Choi, Sungchan; Götze, H.-J.; Meyer, U.; Group, Desire
2011-03-01
A new compilation of Bouguer gravity data stemming from airborne, shipborne and terrestrial data set in the entire Dead Sea Basin (DSB) was reinterpreted by applying 3-D density modelling that incorporated independent information on other geophysical researches allowing for regional and residual filtering in the gravity field, carrying out curvature analysis and Euler deconvolution of the combined gravity field. 3-D density modelling enables us to detailed resolution of upper crustal structures from the southern to the northern subbasin below the saline Dead Sea. 3-D gravity modelling led to the identification of three salt structures, which are found beneath the Sedom area, the Lisan Peninsula and the Dead Sea. In the vicinity of the western margin of the Dead Sea, a salt diapir segment with a thickness of about 4 km has been identified at a top depth of about 2 km, which has not been recognised by any other geophysical interpretations. The thickness of the sedimentary infill overlying the basement in the DSB decreases from 14 km in the vicinity of the Lisan Peninsula to 8 km in the northern and the southern subbasins. Large negative gravity anomalies (lower than -100 × 10-5 m s-2) observed in the DSB correspond with the spatial distribution of salt diapirism with an average density of 2 100 kg m-3. The shallower microearthquakes registered in the DSB are related to the movement of salt diapir in the DSB.
NASA Technical Reports Server (NTRS)
Betts, M.; Tsegaye, T.; Tadesse, W.; Coleman, T. L.; Fahsi, A.
1998-01-01
The spatial and temporal distribution of near surface soil moisture is of fundamental importance to many physical, biological, biogeochemical, and hydrological processes. However, knowledge of these space-time dynamics and the processes which control them remains unclear. The integration of geographic information systems (GIS) and geostatistics together promise a simple mechanism to evaluate and display the spatial and temporal distribution of this vital hydrologic and physical variable. Therefore, this research demonstrates the use of geostatistics and GIS to predict and display soil moisture distribution under vegetated and non-vegetated plots. The research was conducted at the Winfred Thomas Agricultural Experiment Station (WTAES), Hazel Green, Alabama. Soil moisture measurement were done on a 10 by 10 m grid from tall fescue grass (GR), alfalfa (AA), bare rough (BR), and bare smooth (BS) plots. Results indicated that variance associated with soil moisture was higher for vegetated plots than non-vegetated plots. The presence of vegetation in general contributed to the spatial variability of soil moisture. Integration of geostatistics and GIS can improve the productivity of farm lands and the precision of farming.
Tracking and quantifying polymer therapeutic distribution on a cellular level using 3D dSTORM
Hartley, Jonathan M.; Zhang, Rui; Gudheti, Manasa; Yang, Jiyuan; Kopeček, Jindřich
2016-01-01
We used a single-molecule localization technique called direct stochastic optical reconstruction microscopy (dSTORM) to quantify both colocalization and spatial distribution on a cellular level for two conceptually different N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer conjugates. Microscopy images were acquired of entire cells with resolutions as high as 25 nm revealing the nanoscale distribution of the fluorescently labeled therapeutic components. Drug-free macromolecular therapeutics consisting of two self-assembling nanoconjugates showed slight increase in nanoclusters on the cell surface with time. Additionally, dSTORM provided high resolution images of the nanoscale organization of the self-assembling conjugates at the interface between two cells. A conjugate designed for treating ovarian cancer showed that the model drug (Cy3) and polymer bound to Cy5 were colocalized at an early time point before the model drug was enzymatically cleaved from the polymer. Using spatial descriptive statistics it was found that the drug was randomly distributed after 24 h while the polymer bound dye remained in clusters. Four different fluorescent dyes were used and two different therapeutic systems were tested to demonstrate the versatility and possible general applicability of dSTORM for use in studying drug delivery systems. PMID:26855050
NASA Technical Reports Server (NTRS)
Betts, M.; Tsegaye, T.; Tadesse, W.; Coleman, T. L.; Fahsi, A.
1998-01-01
The spatial and temporal distribution of near surface soil moisture is of fundamental importance to many physical, biological, biogeochemical, and hydrological processes. However, knowledge of these space-time dynamics and the processes which control them remains unclear. The integration of geographic information systems (GIS) and geostatistics together promise a simple mechanism to evaluate and display the spatial and temporal distribution of this vital hydrologic and physical variable. Therefore, this research demonstrates the use of geostatistics and GIS to predict and display soil moisture distribution under vegetated and non-vegetated plots. The research was conducted at the Winfred Thomas Agricultural Experiment Station (WTAES), Hazel Green, Alabama. Soil moisture measurement were done on a 10 by 10 m grid from tall fescue grass (GR), alfalfa (AA), bare rough (BR), and bare smooth (BS) plots. Results indicated that variance associated with soil moisture was higher for vegetated plots than non-vegetated plots. The presence of vegetation in general contributed to the spatial variability of soil moisture. Integration of geostatistics and GIS can improve the productivity of farm lands and the precision of farming.
Estimating the 3D Pore Size Distribution of Biopolymer Networks from Directionally Biased Data
Lang, Nadine R.; Münster, Stefan; Metzner, Claus; Krauss, Patrick; Schürmann, Sebastian; Lange, Janina; Aifantis, Katerina E.; Friedrich, Oliver; Fabry, Ben
2013-01-01
The pore size of biopolymer networks governs their mechanical properties and strongly impacts the behavior of embedded cells. Confocal reflection microscopy and second harmonic generation microscopy are widely used to image biopolymer networks; however, both techniques fail to resolve vertically oriented fibers. Here, we describe how such directionally biased data can be used to estimate the network pore size. We first determine the distribution of distances from random points in the fluid phase to the nearest fiber. This distribution follows a Rayleigh distribution, regardless of isotropy and data bias, and is fully described by a single parameter—the characteristic pore size of the network. The bias of the pore size estimate due to the missing fibers can be corrected by multiplication with the square root of the visible network fraction. We experimentally verify the validity of this approach by comparing our estimates with data obtained using confocal fluorescence microscopy, which represents the full structure of the network. As an important application, we investigate the pore size dependence of collagen and fibrin networks on protein concentration. We find that the pore size decreases with the square root of the concentration, consistent with a total fiber length that scales linearly with concentration. PMID:24209841
Yang, Yong; Ning, Gang-Min; Kutor, John; Hong, Di-Hui; Zhang, Mu; Zheng, Xiao-Xiang
2004-01-01
Recent studies have revealed a non-homogeneous distribution of nitric oxide synthase (NOS) in neurons. However, it is not yet clear whether the intracellular distribution of NOS represents the intracellular nitric oxide (NO) distribution. In the present study, software developed in our laboratory was applied to the reconstructed image obtained from confocal slice images in order to project the 3-D reconstructed images in any direction and to cut the neuron in different sections. This enabled the spatial distribution of NO to be visualized in any direction and section. In single neurons, NO distribution was seen to be heterogeneous. After stimulation with glutamate, the spatial changes in different areas of the neuron were different. These findings are consistent with immunocytochemical data on the intracellular localization of nNOS in hippocampus neurons, and will help to elucidate the specificity of nitric oxide signaling. Finally, the administration of SNAP and L-NAME was used to examine DAF-2 distribution in the neurons. The results showed this distribution to be homogenous; therefore, it did not account for the NO distribution results.
Subia, Bano; Dey, Tuli; Sharma, Shaily; Kundu, Subhas C
2015-02-04
To avoid the indiscriminating action of anticancer drugs, the cancer cell specific targeting of drug molecule becomes a preferred choice for the treatment. The successful screening of the drug molecules in 2D culture system requires further validation. The failure of target specific drug in animal model raises the issue of creating a platform in between the in vitro (2D) and in vivo animal testing. The metastatic breast cancer cells migrate and settle at different sites such as bone tissue. This work evaluates the in vitro 3D model of the breast cancer and bone cells to understand the cellular interactions in the presence of a targeted anticancer drug delivery system. The silk fibroin based cytocompatible 3D scaffold is used as in vitro 3D distribution model. Human breast adenocarcinoma and osteoblast like cells are cocultured to evaluate the efficiency of doxorubicin loaded folic acid conjugated silk fibroin nanoparticle as drug delivery system. Decreasing population of the cancer cells, which lower the levels of vascular endothelial growth factors, glucose consumption, and lactate production are observed in the drug treated coculture constructs. The drug treated constructs do not show any major impact on bone mineralization. The diminished expression of osteogenic markers such as osteocalcein and alkaline phosphatase are recorded. The result indicates that this type of silk based 3D in vitro coculture model may be utilized as a bridge between the traditional 2D and animal model system to evaluate the new drug molecule (s) or to reassay the known drug molecules or to develop target specific drug in cancer research.
NASA Astrophysics Data System (ADS)
Garcia, I.; Espinet-González, P.; Rey-Stolle, I.; Barrigón, E.; Algora, C.
2011-12-01
An extended 3D distributed model based on distributed circuit units for the simulation of triple-junction solar cells under realistic conditions for the light distribution has been developed. A special emphasis has been put in the capability of the model to accurately account for current mismatch and chromatic aberration effects. This model has been validated, as shown by the good agreement between experimental and simulation results, for different light spot characteristics including spectral mismatch and irradiance non-uniformities. This model is then used for the prediction of the performance of a triple-junction solar cell for a light spot corresponding to a real optical architecture in order to illustrate its suitability in assisting concentrator system analysis and design process.
NASA Astrophysics Data System (ADS)
Lee, Seunghun; Lee, Jun Ho; Park, Jin Hyoung; Yoon, Yeoreum; Chung, Wan Kyun; Tchah, Hungwon; Kim, Myoung Joon; Kim, Ki Hean
2016-05-01
Moxifloxacin and gatifloxacin are fourth-generation fluoroquinolone antibiotics used in the clinic to prevent or treat ocular infections. Their pharmacokinetics in the cornea is usually measured from extracted ocular fluids or tissues, and in vivo direct measurement is difficult. In this study multiphoton microscopy (MPM), which is a 3D optical microscopic technique based on multiphoton fluorescence, was applied to the measurement of moxifloxacin and gatifloxacin distribution in the cornea. Intrinsic multiphoton fluorescence properties of moxifloxacin and gatifloxacin were characterized, and their distributions in mouse cornea in vivo were measured by 3D MPM imaging. Both moxifloxacin and gatifloxacin had similar multiphoton spectra, while moxifloxacin had stronger fluorescence than gatifloxacin. MPM imaging of mouse cornea in vivo showed (1) moxifloxacin had good penetration through the superficial corneal epithelium, while gatifloxacin had relatively poor penetration, (2) both ophthalmic solutions had high intracellular distribution. In vivo MPM results were consistent with previous studies. This study demonstrates the feasibility of MPM as a method for in vivo direct measurement of moxifloxacin and gatifloxacin in the cornea.
NASA Technical Reports Server (NTRS)
Lin, R. P.; Anderson, K. A.; Ashford, S.; Carlson, C.; Curtis, D.; Ergun, R.; Larson, D.; McFadden, J.; McCarthy, M.; Parks, G. K.
1995-01-01
The 3-D Plasma and Energetic Particle instrument on the GGS Wind spacecraft (launched November 1, 1994) is designed to make measurements of the full three-dimensional distribution of suprathermal electrons and ions from solar wind plasma to low energy cosmic rays, with high sensitivity, wide dynamic range, good energy and angular resolution, and high time resolution. Three pairs of double-ended telescopes, each with two or three closely sandwiched passivated ion implanted silicon detectors measure electrons and ions from approximately 20 keV to greater than or equal to 300 keV. Four top-hat symmetrical spherical section electrostatic analyzers with microchannel plate detectors, a large and a small geometric factor analyzer for electrons and a similar pair for ions, cover from approximately 3 eV to 30 keV. We present preliminary observations of the electron and ion distributions in the absence of obvious solar impulsive events and upstream particles. The quiet time electron energy spectrum shows a smooth approximately power law fall-off extending from the halo population at a few hundred eV to well above approximately 100 keV The quiet time ion energy spectrum also shows significant fluxes over this energy range. Detailed 3-D distributions and their temporal variations will be presented.
Godfrey, A.W.; Holm, E.A.; Hughes, D.A.; Miodownik, M.
1998-12-23
The fundamental difficulties incorporating experimentally obtained-boundary disorientation distributions (BMD) into 3D microstructural models are discussed. An algorithm is described which overcomes these difficulties. The boundary misorientations are treated as a statistical ensemble which is evolved toward the desired BMD using a Monte Carlo method. The application of this algorithm to a number complex arbitrary BMDs shows that the approach is effective for both conserved and non-conserved textures. The algorithm is successfully used to create the BMDs observed in deformation microstructure containing both incidental dislocation boundaries (IDBs) and geometrically necessary boundaries (GNBs).
NASA Astrophysics Data System (ADS)
Steer, Philippe; Lague, Dimitri; Gourdon, Aurélie; Croissant, Thomas; Crave, Alain
2016-04-01
The grain-scale morphology of river sediments and their size distribution are important factors controlling the efficiency of fluvial erosion and transport. In turn, constraining the spatial evolution of these two metrics offer deep insights on the dynamics of river erosion and sediment transport from hillslopes to the sea. However, the size distribution of river sediments is generally assessed using statistically-biased field measurements and determining the grain-scale shape of river sediments remains a real challenge in geomorphology. Here we determine, with new methodological approaches based on the segmentation and geomorphological fitting of 3D point cloud dataset, the size distribution and grain-scale shape of sediments located in river environments. Point cloud segmentation is performed using either machine-learning algorithms or geometrical criterion, such as local plan fitting or curvature analysis. Once the grains are individualized into several sub-clouds, each grain-scale morphology is determined using a 3D geometrical fitting algorithm applied on the sub-cloud. If different geometrical models can be conceived and tested, only ellipsoidal models were used in this study. A phase of results checking is then performed to remove grains showing a best-fitting model with a low level of confidence. The main benefits of this automatic method are that it provides 1) an un-biased estimate of grain-size distribution on a large range of scales, from centimeter to tens of meters; 2) access to a very large number of data, only limited by the number of grains in the point-cloud dataset; 3) access to the 3D morphology of grains, in turn allowing to develop new metrics characterizing the size and shape of grains. The main limit of this method is that it is only able to detect grains with a characteristic size greater than the resolution of the point cloud. This new 3D granulometric method is then applied to river terraces both in the Poerua catchment in New-Zealand and
Size distributions of secondary and primary aerosols in Asia: A 3-D modeling
NASA Astrophysics Data System (ADS)
Yu, F.; Luo, G.; Wang, Z.
2009-12-01
Asian aerosols have received increasing attention because of their potential health and climate effects and the rapid increasing of Asian emissions associated with accelerating economic expansion. Aerosol particles appear in the atmosphere due to either in-situ nucleation (i.e, secondary particles) or direct emissions (i.e., primary particles), and their environmental impacts depend strongly on their concentrations, sizes, compositions, and mixing states. A size-resolved (sectional) particle microphysics model with a number of computationally efficient schemes has been incorporated into a global chemistry transport model (GEOS-Chem) to simulate the number size distributions of secondary and primary particles in the troposphere (Yu and Luo, Atmos. Chem. Phys. Discuss., 9, 10597-10645, 2009). The growth of nucleated particles through the condensation of sulfuric acid vapor and equilibrium uptake of nitrate, ammonium, and secondary organic aerosol is explicitly simulated, along with the coating of primary particles (dust, black carbon, organic carbon, and sea salt) by volatile components via condensation and coagulation with secondary particles. Here we look into the spatiotemporal variations of the size distributions of secondary and primary aerosols in Asia. The annual mean number concentration of the accumulation mode particles (dry diameter > ~ 100 nm) in the lower troposphere over Asia (especially China) is very high and is dominated (~70-90%) by carbonaceous primary particles (with coated condensable species). Coagulation and condensation turn the primary particles into mixed particles and on average increase the dry sizes of primary particles by a factor of ~ 2-2.5. Despite of high condensation sink, sulfuric acid vapor concentration in many parts of Asian low troposphere is very high (annual mean values above 1E7/cm3) and significant new particle formation still occurs. Secondary particles generally dominate the particles small than 100 nm and the equilibrium
3D Spatial Distribution of the Intergalactic Medium: The ESO Blues?
NASA Astrophysics Data System (ADS)
Rollinde, Emmanuel; Petitjean, Patrick; Pichon, Christophe; Colombi, Stéphane; Aracil, Bastien
The numerous absorption lines seen in the spectra of distant quasars (the so-called Lyman-α forest) reveal the intergalactic medium (IGM) up to redshifts larger than 5. It is believed that the space distribution of the gas traces the potential wells of the dark matter. Indeed, recent numerical N-body simulations have been successful at reproducing the observed characteristics of the Lyman-α forest (e.g. [1][12][5]). The IGM is therefore seen as a smooth pervasive medium which can be used to study the spatial distribution of the mass on scales larger than the Jeans' length. This idea is reinforced by observations of multiple lines of sight. It is observed that the Lyman-α forest is fairly homogeneous on scale smaller than 100 kpc (e.g. [11]) and highly correlated on scale up to one megaparsec (e.g. [13][3]). The number of suitable multiple lines of sight is small however and the sample need to be significantly enlarged before any firm conclusion can be drawn (see Section 3.3).
NASA Astrophysics Data System (ADS)
Wilde-Piorko, M.; Polkowski, M.
2016-12-01
Seismic wave travel time calculation is the most common numerical operation in seismology. The most efficient is travel time calculation in 1D velocity model - for given source, receiver depths and angular distance time is calculated within fraction of a second. Unfortunately, in most cases 1D is not enough to encounter differentiating local and regional structures. Whenever possible travel time through 3D velocity model has to be calculated. It can be achieved using ray calculation or time propagation in space. While single ray path calculation is quick it is complicated to find the ray path that connects source with the receiver. Time propagation in space using Fast Marching Method seems more efficient in most cases, especially when there are multiple receivers. In this presentation final release of a Python module pySeismicFMM is presented - simple and very efficient tool for calculating travel time from sources to receivers. Calculation requires regular 2D or 3D velocity grid either in Cartesian or geographic coordinates. On desktop class computer calculation speed is 200k grid cells per second. Calculation has to be performed once for every source location and provides travel time to all receivers. pySeismicFMM is free and open source. Development of this tool is a part of authors PhD thesis. Source code of pySeismicFMM will be published before Fall Meeting. National Science Centre Poland provided financial support for this work via NCN grant DEC-2011/02/A/ST10/00284.
NASA Astrophysics Data System (ADS)
Polkowski, Marcin
2016-04-01
Seismic wave travel time calculation is the most common numerical operation in seismology. The most efficient is travel time calculation in 1D velocity model - for given source, receiver depths and angular distance time is calculated within fraction of a second. Unfortunately, in most cases 1D is not enough to encounter differentiating local and regional structures. Whenever possible travel time through 3D velocity model has to be calculated. It can be achieved using ray calculation or time propagation in space. While single ray path calculation is quick it is complicated to find the ray path that connects source with the receiver. Time propagation in space using Fast Marching Method seems more efficient in most cases, especially when there are multiple receivers. In this presentation a Python module pySeismicFMM is presented - simple and very efficient tool for calculating travel time from sources to receivers. Calculation requires regular 2D or 3D velocity grid either in Cartesian or geographic coordinates. On desktop class computer calculation speed is 200k grid cells per second. Calculation has to be performed once for every source location and provides travel time to all receivers. pySeismicFMM is free and open source. Development of this tool is a part of authors PhD thesis. National Science Centre Poland provided financial support for this work via NCN grant DEC-2011/02/A/ST10/00284.
SU-E-T-423: Fast Photon Convolution Calculation with a 3D-Ideal Kernel On the GPU
Moriya, S; Sato, M; Tachibana, H
2015-06-15
Purpose: The calculation time is a trade-off for improving the accuracy of convolution dose calculation with fine calculation spacing of the KERMA kernel. We investigated to accelerate the convolution calculation using an ideal kernel on the Graphic Processing Units (GPU). Methods: The calculation was performed on the AMD graphics hardware of Dual FirePro D700 and our algorithm was implemented using the Aparapi that convert Java bytecode to OpenCL. The process of dose calculation was separated with the TERMA and KERMA steps. The dose deposited at the coordinate (x, y, z) was determined in the process. In the dose calculation running on the central processing unit (CPU) of Intel Xeon E5, the calculation loops were performed for all calculation points. On the GPU computation, all of the calculation processes for the points were sent to the GPU and the multi-thread computation was done. In this study, the dose calculation was performed in a water equivalent homogeneous phantom with 150{sup 3} voxels (2 mm calculation grid) and the calculation speed on the GPU to that on the CPU and the accuracy of PDD were compared. Results: The calculation time for the GPU and the CPU were 3.3 sec and 4.4 hour, respectively. The calculation speed for the GPU was 4800 times faster than that for the CPU. The PDD curve for the GPU was perfectly matched to that for the CPU. Conclusion: The convolution calculation with the ideal kernel on the GPU was clinically acceptable for time and may be more accurate in an inhomogeneous region. Intensity modulated arc therapy needs dose calculations for different gantry angles at many control points. Thus, it would be more practical that the kernel uses a coarse spacing technique if the calculation is faster while keeping the similar accuracy to a current treatment planning system.
Senkesen, Oznur; Tezcanli, Evrim; Buyuksarac, Bora; Ozbay, Ismail
2014-01-01
Radiation fluence changes caused by the dosimeter itself and poor spatial resolution may lead to lack of 3-dimensional (3D) information depending on the features of the dosimeter and quality assurance of dose distributions for high-dose rate (HDR) iridium-192 ((192)Ir) brachytherapy sources is challenging and experimental dosimetry methods used for brachytherapy sources are limited. In this study, we investigated 3D dose distributions of (192)Ir brachytherapy sources for irradiation with single and multiple dwell positions using a normoxic gel dosimeter and compared them with treatment planning system (TPS) calculations. For dose calibration purposes, 100-mL gel-containing vials were irradiated at predefined doses and then scanned in an magnetic resonance (MR) imaging unit. Gel phantoms prepared in 2 spherical glasses were irradiated with (192)Ir for the calculated dwell positions, and MR scans of the phantoms were obtained. The images were analyzed with MATLAB software. Dose distributions and profiles derived with 1-mm resolution were compared with TPS calculations. Linearity was observed between the delivered dose and the reciprocal of the T2 relaxation time constant of the gel. The x-, y-, and z-axes were defined as the sagittal, coronal, and axial planes, respectively, the sagittal and axial planes were defined parallel to the long axis of the source while the coronal plane was defined horizontally to the long axis of the source. The differences between measured and calculated profile widths of 3-cm source length and point source for 70%, 50%, and 30% isodose lines were evaluated at 3 dose levels using 18 profiles of comparison. The calculations for 3-cm source length revealed a difference of > 3mm in 1 coordinate at 50% profile width on the sagittal plane and 3 coordinates at 70% profile width and 2 coordinates at 50% and 30% profile widths on the axial plane. Calculations on the coronal plane for 3-cm source length showed > 3-mm difference in 1 coordinate at
Senkesen, Oznur; Tezcanli, Evrim; Buyuksarac, Bora; Ozbay, Ismail
2014-10-01
Radiation fluence changes caused by the dosimeter itself and poor spatial resolution may lead to lack of 3-dimensional (3D) information depending on the features of the dosimeter and quality assurance of dose distributions for high–dose rate (HDR) iridium-192 ({sup 192}Ir) brachytherapy sources is challenging and experimental dosimetry methods used for brachytherapy sources are limited. In this study, we investigated 3D dose distributions of {sup 192}Ir brachytherapy sources for irradiation with single and multiple dwell positions using a normoxic gel dosimeter and compared them with treatment planning system (TPS) calculations. For dose calibration purposes, 100-mL gel-containing vials were irradiated at predefined doses and then scanned in an magnetic resonance (MR) imaging unit. Gel phantoms prepared in 2 spherical glasses were irradiated with {sup 192}Ir for the calculated dwell positions, and MR scans of the phantoms were obtained. The images were analyzed with MATLAB software. Dose distributions and profiles derived with 1-mm resolution were compared with TPS calculations. Linearity was observed between the delivered dose and the reciprocal of the T2 relaxation time constant of the gel. The x-, y-, and z-axes were defined as the sagittal, coronal, and axial planes, respectively, the sagittal and axial planes were defined parallel to the long axis of the source while the coronal plane was defined horizontally to the long axis of the source. The differences between measured and calculated profile widths of 3-cm source length and point source for 70%, 50%, and 30% isodose lines were evaluated at 3 dose levels using 18 profiles of comparison. The calculations for 3-cm source length revealed a difference of > 3 mm in 1 coordinate at 50% profile width on the sagittal plane and 3 coordinates at 70% profile width and 2 coordinates at 50% and 30% profile widths on the axial plane. Calculations on the coronal plane for 3-cm source length showed > 3-mm difference in 1
Toward Measuring Galactic Dense Molecular Gas Properties and 3D Distribution with Hi-GAL
NASA Astrophysics Data System (ADS)
Zetterlund, Erika; Glenn, Jason; Maloney, Phil
2016-01-01
The Herschel Space Observatory's submillimeter dust continuum survey Hi-GAL provides a powerful new dataset for characterizing the structure of the dense interstellar medium of the Milky Way. Hi-GAL observed a 2° wide strip covering the entire 360° of the Galactic plane in broad bands centered at 70, 160, 250, 350, and 500 μm, with angular resolution ranging from 10 to 40 arcseconds. We are adapting a molecular cloud clump-finding algorithm and a distance probability density function distance-determination method developed for the Bolocam Galactic Plane Survey (BGPS) to the Hi-GAL data. Using these methods we expect to generate a database of 105 cloud clumps, derive distance information for roughly half the clumps, and derive precise distances for approximately 20% of them. With five-color photometry and distances, we will measure the cloud clump properties, such as luminosities, physical sizes, and masses, and construct a three-dimensional map of the Milky Way's dense molecular gas distribution.The cloud clump properties and the dense gas distribution will provide critical ground truths for comparison to theoretical models of molecular cloud structure formation and galaxy evolution models that seek to emulate spiral galaxies. For example, such models cannot resolve star formation and use prescriptive recipes, such as converting a fixed fraction of interstellar gas to stars at a specified interstellar medium density threshold. The models should be compared to observed dense molecular gas properties and galactic distributions.As a pilot survey to refine the clump-finding and distance measurement algorithms developed for BGPS, we have identified molecular cloud clumps in six 2° × 2° patches of the Galactic plane, including one in the inner Galaxy along the line of sight through the Molecular Ring and the termination of the Galactic bar and one toward the outer Galaxy. Distances have been derived for the inner Galaxy clumps and compared to Bolocam Galactic Plane
High-Performance Computation of Distributed-Memory Parallel 3D Voronoi and Delaunay Tessellation
Peterka, Tom; Morozov, Dmitriy; Phillips, Carolyn
2014-11-14
Computing a Voronoi or Delaunay tessellation from a set of points is a core part of the analysis of many simulated and measured datasets: N-body simulations, molecular dynamics codes, and LIDAR point clouds are just a few examples. Such computational geometry methods are common in data analysis and visualization; but as the scale of simulations and observations surpasses billions of particles, the existing serial and shared-memory algorithms no longer suffice. A distributed-memory scalable parallel algorithm is the only feasible approach. The primary contribution of this paper is a new parallel Delaunay and Voronoi tessellation algorithm that automatically determines which neighbor points need to be exchanged among the subdomains of a spatial decomposition. Other contributions include periodic and wall boundary conditions, comparison of our method using two popular serial libraries, and application to numerous science datasets.
Löb, D; Lengert, N; Chagin, V O; Reinhart, M; Casas-Delucchi, C S; Cardoso, M C; Drossel, B
2016-04-07
DNA replication dynamics in cells from higher eukaryotes follows very complex but highly efficient mechanisms. However, the principles behind initiation of potential replication origins and emergence of typical patterns of nuclear replication sites remain unclear. Here, we propose a comprehensive model of DNA replication in human cells that is based on stochastic, proximity-induced replication initiation. Critical model features are: spontaneous stochastic firing of individual origins in euchromatin and facultative heterochromatin, inhibition of firing at distances below the size of chromatin loops and a domino-like effect by which replication forks induce firing of nearby origins. The model reproduces the empirical temporal and chromatin-related properties of DNA replication in human cells. We advance the one-dimensional DNA replication model to a spatial model by taking into account chromatin folding in the nucleus, and we are able to reproduce the spatial and temporal characteristics of the replication foci distribution throughout S-phase.
Löb, D.; Lengert, N.; Chagin, V. O.; Reinhart, M.; Casas-Delucchi, C. S.; Cardoso, M. C.; Drossel, B.
2016-01-01
DNA replication dynamics in cells from higher eukaryotes follows very complex but highly efficient mechanisms. However, the principles behind initiation of potential replication origins and emergence of typical patterns of nuclear replication sites remain unclear. Here, we propose a comprehensive model of DNA replication in human cells that is based on stochastic, proximity-induced replication initiation. Critical model features are: spontaneous stochastic firing of individual origins in euchromatin and facultative heterochromatin, inhibition of firing at distances below the size of chromatin loops and a domino-like effect by which replication forks induce firing of nearby origins. The model reproduces the empirical temporal and chromatin-related properties of DNA replication in human cells. We advance the one-dimensional DNA replication model to a spatial model by taking into account chromatin folding in the nucleus, and we are able to reproduce the spatial and temporal characteristics of the replication foci distribution throughout S-phase. PMID:27052359
The internal density distribution of comet 67P/C-G based on 3D models
NASA Astrophysics Data System (ADS)
Jorda, Laurent; Faurschou Hviid, Stubbe; Capanna, Claire; Gaskell, Robert W.; Gutiérrez, Pedro; Preusker, Frank; Scholten, Frank; Rodionov, Sergey; OSIRIS Team
2016-10-01
The OSIRIS camera aboard the Rosetta spacecraft observed the nucleus of comet 67P/C-G from the mapping phase in summer 2014 until now. The images have allowed the reconstruction in three-dimension of nucleus surface with stereophotogrammetry (Preusker et al., Astron. Astrophys.) and stereophotoclinometry (Jorda et al., Icarus) techniques. We use the reconstructed models to constrain the internal density distribution based on: (i) the measurement of the offset between the center of mass and the center of figure of the object, and (ii) the assumption that flat areas observed at the surface of the comet correspond to iso-gravity surfaces. The results of our analysis will be presented, and the consequences for the internal structure and formation of the nucleus of comet 67P/C-G will be discussed.
The internal density distribution of comet 67P/C-G based on 3D models
NASA Astrophysics Data System (ADS)
Jorda, Laurent; Hviid, Stubbe; Capanna, Claire; Gaskell, Robert; Gutierrez, Pedro; Preusker, Frank; Rodionov, Sergey; Scholten, Frank
2016-04-01
The OSIRIS camera aboard the Rosetta spacecraft observed the nucleus of comet 67P/C-G from the mapping phase in summer 2014 until now. The images have allowed the reconstruction in three-dimension of nucleus surface with stereophotogrammetry (Preusker et al., Astron. Astrophys.) and stereophotoclinometry (Jorda et al., submitted to Icarus) techniques. We use the reconstructed models to constrain the internal density distribution based on: (i) the measurement of the offset between the center of mass and center of figure of the object, and (ii) the assumption that flat areas observed at the surface of the comet correspond to iso-gravity surfaces. The results of our analysis will be presented, and the consequences for the internal structure and formation of the nucleus of comet 67P/C-G will be discussed.
Operator counting and eigenvalue distributions for 3D supersymmetric gauge theories
NASA Astrophysics Data System (ADS)
Gulotta, Daniel R.; Herzog, Christopher P.; Pufu, Silviu S.
2011-11-01
We give further support for our conjecture relating eigenvalue distributions of the Kapustin-Willett-Yaakov matrix model in the large N limit to numbers of operators in the chiral ring of the corresponding supersymmetric three-dimensional gauge theory. We show that the relation holds for non-critical R-charges and for examples with mathcal{N} = {2} instead of mathcal{N} = {3} supersymmetry where the bifundamental matter fields are nonchiral. We prove that, for non-critical R-charges, the conjecture is equivalent to a relation between the free energy of the gauge theory on a three sphere and the volume of a Sasaki manifold that is part of the moduli space of the gauge theory. We also investigate the consequences of our conjecture for chiral theories where the matrix model is not well understood.
NASA Astrophysics Data System (ADS)
Koike, Katsuaki; Kubo, Taiki; Liu, Chunxue; Masoud, Alaa; Amano, Kenji; Kurihara, Arata; Matsuoka, Toshiyuki; Lanyon, Bill
2015-10-01
This study integrates 3D models of rock fractures from different sources and hydraulic properties aimed at identifying relationships between fractures and permeability. The Tono area in central Japan, chiefly overlain by Cretaceous granite, was examined because of the availability of a unique dataset from deep borehole data at 26 sites. A geostatistical method (GEOFRAC) that can incorporate orientations of sampled data was applied to 50,900 borehole fractures for spatial modeling of fractures over a 12 km by 8 km area, to a depth of 1.5 km. GEOFRAC produced a plausible 3D fracture model, in that the orientations of simulated fractures correspond to those of the sample data and the continuous fractures appeared near a known fault. Small-scale fracture distributions with dominant orientations were also characterized around the two shafts using fracture data from the shaft walls. By integrating the 3D model of hydraulic conductivity using sequential Gaussian simulation with the GEOFRAC fractures from the borehole data, the fracture sizes and directions that strongly affect permeable features were identified. Four fracture-related elements: lineaments from a shaded 10-m DEM, GEOFRAC fractures using the borehole and shaft data, and microcracks from SEM images, were used for correlating fracture attributes at different scales. The consistency of the semivariogram models of distribution densities was identified. Using an experimental relationship between hydraulic conductivity and fracture length, the fractures that typically affect the hydraulic properties at the drift scale were surmised to be in the range 100-200 m. These results are useful for a comprehensive understanding of rock fracture systems and their hydraulic characteristics at multiple scales in a target area.
NASA Astrophysics Data System (ADS)
Park, Hye-Suk; Kim, Ye-Seul; Lee, Haeng-Hwa; Gang, Won-Suk; Kim, Hee-Joung; Choi, Young-Wook; Choi, JaeGu
2015-08-01
The purpose of this study is to determine the optimal non-uniform angular dose distribution to improve the quality of the 3D reconstructed images and to acquire extra 2D projection images. In this analysis, 7 acquisition sets were generated by using four different values for the number of projections (11, 15, 21, and 29) and total angular range (±14°, ±17.5°, ±21°, and ±24.5° ). For all acquisition sets, the zero-degree projection was used as the 2D image that was close to that of standard conventional mammography (CM). Exposures used were 50, 100, 150, and 200 mR for the zero-degree projection, and the remaining dose was distributed over the remaining projection angles. To quantitatively evaluate image quality, we computed the CNR (contrast-to-noise ratio) and the ASF (artifact spread function) for the same radiation dose. The results indicate that, for microcalcifications, acquisition sets with approximately 4 times higher exposure on the zero-degree projection than the average exposure for the remaining projection angles yielded higher CNR values and were 3% higher than the uniform distribution. However, very high dose concentrations toward the zero-degree projection may reduce the quality of the reconstructed images due to increasing noise in the peripheral views. The zero-degree projection of the non-uniform dose distribution offers a 2D image similar to that of standard CM, but with a significantly lower radiation dose. Therefore, we need to evaluate the diagnostic potential of extra 2D projection image when diagnose breast cancer by using 3D images with non-uniform angular dose distributions.
On the spatial distribution of seismicity and the 3D tectonic stress field in western Greece
NASA Astrophysics Data System (ADS)
Kassaras, Ioannis; Kapetanidis, Vasilis; Karakonstantis, Andreas
2016-10-01
We analyzed a large number of focal mechanisms and relocated earthquake hypocenters to investigate the geodynamics of western Greece, the most seismically active part of the Aegean plate-boundary zone. This region was seismically activated multiple times during the last decade, providing a large amount of enhanced quality new information that was obtained by the Hellenic Unified Seismological Network (HUSN). Relocated seismicity using a double-difference method appears to be concentrated above ∼35 km depth, exhibiting spatial continuity along the convergence boundary and being clustered elsewhere. Earthquakes are confined within the accreted sediments escarpment of the down-going African plate against the un-deformed Eurasian hinterland. The data arrangement shows that Pindos constitutes a seismic boundary along which large stress heterogeneities occur. In Cephalonia no seismicity is found to be related with the offshore Cephalonia Transform Fault (CTF). Onshore, Nsbnd S crustal extension dominates, while in central and south Peloponnesus the stress field appears rotated by 90°. Shearing-stress obliquity by 30° is indicated along the major strike-slip faults, consistent with clockwise crustal rotation. Within the lower crust, the stress field appears affected by plate kinematics and distributed deformation of the lower crust and upper mantle, which guide the regional geodynamics.
STRUCTURE IN THE 3D GALAXY DISTRIBUTION. II. VOIDS AND WATERSHEDS OF LOCAL MAXIMA AND MINIMA
Way, M. J.; Gazis, P. R.; Scargle, Jeffrey D. E-mail: PGazis@sbcglobal.net
2015-01-20
The major uncertainties in studies of the multi-scale structure of the universe arise not from observational errors but from the variety of legitimate definitions and detection methods for individual structures. To facilitate the study of these methodological dependencies, we have carried out 12 different analyses defining structures in various ways. This has been done in a purely geometrical way by utilizing the HOP algorithm as a unique parameter-free method of assigning groups of galaxies to local density maxima or minima. From three density estimation techniques (smoothing kernels, Bayesian blocks, and self-organizing maps) applied to three data sets (the Sloan Digital Sky Survey Data Release 7, the Millennium simulation, and randomly distributed points) we tabulate information that can be used to construct catalogs of structures connected to local density maxima and minima. We also introduce a void finder that utilizes a method to assemble Delaunay tetrahedra into connected structures and characterizes regions empty of galaxies in the source catalog.
3D measurement of the radiation distribution in a water phantom in a hadron therapy beam
NASA Astrophysics Data System (ADS)
Opalka, L.; Granja, C.; Hartmann, B.; Jakubek, J.; Jaekel, O.; Martisikova, M.; Pospisil, S.; Solc, J.
2012-01-01
Hadron therapy is a highly precise radio-therapeutic method with many advantages especially in cases when the tumour is close to sensitive organs where standard treatments cannot be used. For reliable treatment planning it is necessary to have calculation tools for maximization of the dose delivered to the targeted tissue and minimization of the dose outside of it. While the main physical processes in material irradiated by hadron beams are known, in reality the processes involved are complex so that analytical computations are impossible. Thus, the planning tools to incorporate simplified models and numerical approximations and an experimental method for high precision verification of the models within phantoms is desired. The development of sensitive, high resolution and online methods for measurement of the radiation environment inside of the irradiated object is the aim of this work. Such measurements are made possible by the resolving power of the state-of-the-art pixel detector Timepix. This quantum counting imaging device is able to record the characteristic shapes of the particle traces including their energies deposited in the detector. All these data recorded for each event allow to estimate the particle type, its energy and direction of flight. Event-by-event analysis is done using pattern recognition of the characteristic traces. The objective of the experiment is the detection and characterization of secondary radiation generated by the primary therapeutic beams in tissue equivalent material (water). Measurements were performed inside of a water phantom irradiated by a carbon beam at the Heidelberg Ion-Beam Therapy Center (HIT).
Wu, Jingpeng; Guo, Congdi; Chen, Shangbin; Jiang, Tao; He, Yong; Ding, Wenxiang; Yang, Zhongqin; Luo, Qingming; Gong, Hui
2016-01-01
Whether vascular distribution is spatially specific among cortical columns is a fundamental yet controversial question. Here, we have obtained 1-μm resolution 3D datasets that cover the whole mouse barrel cortex by combining Nissl staining with micro-optical sectioning tomography to simultaneously visualize individual cells and blood vessels, including capillaries. Pinpointing layer IV of the posteromedial barrel subfield, direct 3D reconstruction and quantitative analysis showed that (1) penetrating vessels preferentially locate in the interbarrel septa/barrel wall (75.1%) rather than the barrel hollows, (2) the branches of 70% penetrating vessels only reach the neighboring but not always all the neighboring barrels and the other 30% extend beyond the neighboring barrels and may provide cross-barrel blood supply or drainage, (3) the branches of 59.6% penetrating vessels reach all the neighboring barrels, while the rest only reach part of them, and (4) the length density of microvessels in the interbarrel septa/barrel wall is lower than that in the barrel hollows with a ratio of 0.92. These results reveal that the penetrating vessels and microvessels exhibit a barrel-specific organization, whereas the branches of penetrating vessels do not, which suggests a much more complex vascular distribution pattern among cortical columns than previously thought. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
Effect of 3D stall-cells on the pressure distribution of a laminar NACA64-418 wing
NASA Astrophysics Data System (ADS)
Ragni, Daniele; Ferreira, Carlos
2016-08-01
A 3D stall-cell flow-field has been studied in a 4.8 aspect-ratio wing obtained by linear extrusion of a laminar NACA64-418 airfoil profile. The span-wise change in the velocity and pressure distribution along the wing has been quantified with respect to the development of cellular structures from 8° to 20° angle of attack. Oil-flow visualizations help localizing the regular cellular pattern in function of the angle of attack. Multi-plane stereoscopic PIV measurements obtained by traversing the entire setup along the wing span show that the flow separation is not span-wise uniform. The combination of different stereoscopic fields into a 3D volume of velocity data allows studying the global effect of the stall-cell pattern on the wing flow. Integration of the experimentally computed pressure gradient from the Navier-Stokes equation is employed to compute the span-wise distribution of the mean surface pressure. Comparison of the results with the ones obtained from pressure taps installed in the wing evidences a span-wise periodic loading on the wing. The periodic loading has maxima confined in the stream-wise direction between the location of the highest airfoil curvature and the one of the airfoil flow separation. Estimation of the periodic loading is found within 2-6 % of the sectional wing lift.
NASA Astrophysics Data System (ADS)
Morel, X.; Berthomier, M.; Berthelier, J.-J.
2017-03-01
We describe the concept and properties of a new electrostatic optic which aims to provide a 2π sr instantaneous field of view to characterize space plasmas. It consists of a set of concentric toroidal electrodes that form a number of independent energy-selective channels. Charged particles are deflected toward a common imaging planar detector. The full 3-D distribution function of charged particles is obtained through a single energy sweep. Angle and energy resolution of the optics depends on the number of toroidal electrodes, on their radii of curvature, on their spacing, and on the angular aperture of the channels. We present the performances, as derived from numerical simulations, of an initial implementation of this concept that would fit the need of many space plasma physics applications. The proposed instrument has 192 entrance windows corresponding to eight polar channels each with 24 azimuthal sectors. The initial version of this 3-D plasma analyzer may cover energies from a few eV up to 30 keV, typically with a channel-dependent energy resolution varying from 10% to 7%. The angular acceptance varies with the direction of the incident particle from 3° to 12°. With a total geometric factor of two sensor heads reaching 0.23 cm2 sr eV/eV, this "donut" shape analyzer has enough sensitivity to allow very fast measurements of plasma distribution functions in most terrestrial and planetary environments on three-axis stabilized as well as on spinning satellites.
3D finite element analysis to detect stress distribution: spiral family implants.
Danza, Matteo; Zollino, Ilaria; Paracchini, Luigi; Riccardo, Guidi; Fanali, Stefano; Carinci, Francesco
2009-12-01
Spiral family implants are a root-form fixtures with increasing thickness of tread. This characteristic gives a self-tapping and self-condensing bone properties to implants. To study spiral family implant inserted in different bone quality and connected with abutments of different angulations a Finite Element Analysis (FEA) was performed. Once drawn the systems that were object of the study by CAD (Computer Aided Design), the FEA discretized solids composing the system in many infinitesimal little elementary solids defined finite elements. This lead to a mesh formation where the single finite elements were connected among them by nodes. For the 3 units bone-implant-abutments several thousand of tetrahedral elements having 10 parabolic nodes were employed. The biomechanical behaviour of 4.2 mm × 13 mm dental implants, connecting screw, straight and 15° and 25° angulated abutment subjected to static loads, in contact with high and poor bone quality was evaluated by FEA. A double system was analyzed: a) FY strength acting along Y axis and having 200 N intensity; b) FY and FZ couple of strengths applied along Y and Z directions and having respectively 200N and 140N intensity. The materials were considered as homogeneous, linear and isotropic. Then the FEA simulation was performed hypothesizing a linearity between loads and deformations. The lowest stress value was found in the system composed by implants and straight abutments loaded with a vertical strength, while the highest stress value were found in implants and 15° angulated abutment loaded with a angulated strength. In addition, the lower is the bone quality (i.e. D4) the higher is the distribution of the stress within the bone. Spiral family implants can be used successfully in low bone quality but a straight force is recommended.
Nakamoto, Takahiro; Arimura, Hidetaka; Nakamura, Katsumasa; Shioyama, Yoshiyuki; Mizoguchi, Asumi; Hirose, Taka-Aki; Honda, Hiroshi; Umezu, Yoshiyuki; Nakamura, Yasuhiko; Hirata, Hideki
2015-03-01
A computerized framework for monitoring four-dimensional (4D) dose distributions during stereotactic body radiation therapy based on a portal dose image (PDI)-based 2D/3D registration approach has been proposed in this study. Using the PDI-based registration approach, simulated 4D "treatment" CT images were derived from the deformation of 3D planning CT images so that a 2D planning PDI could be similar to a 2D dynamic clinical PDI at a breathing phase. The planning PDI was calculated by applying a dose calculation algorithm (a pencil beam convolution algorithm) to the geometry of the planning CT image and a virtual water equivalent phantom. The dynamic clinical PDIs were estimated from electronic portal imaging device (EPID) dynamic images including breathing phase data obtained during a treatment. The parameters of the affine transformation matrix were optimized based on an objective function and a gamma pass rate using a Levenberg-Marquardt (LM) algorithm. The proposed framework was applied to the EPID dynamic images of ten lung cancer patients, which included 183 frames (mean: 18.3 per patient). The 4D dose distributions during the treatment time were successfully obtained by applying the dose calculation algorithm to the simulated 4D "treatment" CT images. The mean±standard deviation (SD) of the percentage errors between the prescribed dose and the estimated dose at an isocenter for all cases was 3.25±4.43%. The maximum error for the ten cases was 14.67% (prescribed dose: 1.50Gy, estimated dose: 1.72Gy), and the minimum error was 0.00%. The proposed framework could be feasible for monitoring the 4D dose distribution and dose errors within a patient's body during treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.
NASA Technical Reports Server (NTRS)
Walitt, L.
1984-01-01
A three-dimensional viscous computer code (VANS/MD) was employed to calculate the turbulent flow field at the end wall leading edge region of a 20 inch axial annular turbine cascade. The initial boundary layer roll-up and formation of the end wall vortices were computed at the vane leading edge. The calculated flow field was found to be periodic with a frequency of approximately 1600 Hz. The calculated size of the separation region for the hub endwall vortex compared favorably with measured endwall oil traces. In an effort to determine the effects of the turbulence model on the calculated unsteadiness, a laminar calculation was made. The periodic nature of the calculated flow field persisted with the frequency essentially unchanged.
Calculating Cumulative Binomial-Distribution Probabilities
NASA Technical Reports Server (NTRS)
Scheuer, Ernest M.; Bowerman, Paul N.
1989-01-01
Cumulative-binomial computer program, CUMBIN, one of set of three programs, calculates cumulative binomial probability distributions for arbitrary inputs. CUMBIN, NEWTONP (NPO-17556), and CROSSER (NPO-17557), used independently of one another. Reliabilities and availabilities of k-out-of-n systems analyzed. Used by statisticians and users of statistical procedures, test planners, designers, and numerical analysts. Used for calculations of reliability and availability. Program written in C.
NASA Astrophysics Data System (ADS)
Gómez-Muñoz, José Luis; Bravo-Castillero, Julián
2008-08-01
The study of the effective properties of composite materials with anisotropic constituents and different inclusion shapes has motivated the development of the Mathematica 6.0 package "CompositeMaterials". This package can be used to calculate the effective anisotropic conductivity tensor of two-phase composites. Any fiber cross section, even percolating ones, can be studied in the 2D composites. "Rectangular Prism" and "Ellipsoidal" inclusion shapes with arbitrary orientations can be investigated in the 3D composites. This package combines the Asymptotic Homogenization Method and the Finite Element Method in order to obtain the effective conductivity tensor. The commands and options of the package are illustrated with two sample applications for two- and three-dimensional composites. Program summaryProgram title:CompositeMaterials Catalogue identifier:AEAU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAU_v1_0.html Program obtainable from:CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions:Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.:132 183 No. of bytes in distributed program, including test data, etc.:1 334 908 Distribution format:tar.gz Programming language:Mathematica 6.0 Computer:Any that can run Mathematica 6.0 and where the open-source free C-programs Triangle ( http://www.cs.cmu.edu/ quake/triangle.html) and TetGen ( http://tetgen.berlios.de/) can be compiled and executed. Tested in Intel Pentium computers. Operating system:Any that can run Mathematica 6.0 and where the open-source free C-programs Triangle ( http://www.cs.cmu.edu/ quake/triangle.html) and TetGen ( http://tetgen.berlios.de/) can be compiled and executed. Tested in Windows XP. RAM:Small two-dimensional calculations require less than 100 MB. Large three-dimensional calculations require 500 MB or more. Classification:7.9 External routines:One Mathematica Add-on and
Benchmark of Atucha-2 PHWR RELAP5-3D control rod model by Monte Carlo MCNP5 core calculation
Pecchia, M.; D'Auria, F.; Mazzantini, O.
2012-07-01
Atucha-2 is a Siemens-designed PHWR reactor under construction in the Republic of Argentina. Its geometrical complexity and peculiarities require the adoption of advanced Monte Carlo codes for performing realistic neutronic simulations. Therefore core models of Atucha-2 PHWR were developed using MCNP5. In this work a methodology was set up to collect the flux in the hexagonal mesh by which the Atucha-2 core is represented. The scope of this activity is to evaluate the effect of obliquely inserted control rod on neutron flux in order to validate the RELAP5-3D{sup C}/NESTLE three dimensional neutron kinetic coupled thermal-hydraulic model, applied by GRNSPG/UNIPI for performing selected transients of Chapter 15 FSAR of Atucha-2. (authors)
NASA Astrophysics Data System (ADS)
Gaidies, Fred; Petley-Ragan, Arianne; Pattison, David
2016-04-01
The size, abundance, shape and spatial distribution of metamorphic minerals bears important information on the rates and mechanisms of fundamental processes that take place during metamorphic crystallization. X-ray computed tomography (XR-CT) has become the method of choice to study the three-dimensional (3D) disposition of minerals in rocks as it allows investigation of relatively large sample volumes at sufficiently high resolution required for statistically meaningful analyses, and as its non-destructive fashion permits further studies such as mineral chemical, isotopic or crystallographic analyses of select grains identified through XR-CT. We present results obtained through the quantification of the 3D disposition of cordierite and biotite crystals in a hornfels from the contact aureole of the Bugaboo Batholith (British Columbia, Canada) using XR-CT and global as well as scale-dependent pattern statistics (Petley-Ragan et al., 2016). The results demonstrate a random distribution of cordierite and biotite crystal sizes for all scales across the entire rock volume studied indicative of interface-controlled prograde metamorphic reaction kinetics. We show that the common approach to approximate the shape of crystals as spherical underestimates the influence of the Strauss hard-core process on rock texture which may be misinterpreted to reflect ordering of crystal sizes by inhibition of nucleation and growth commonly associated with diffusion-controlled reaction kinetics. According to our findings, Strauss hard-core ordering develops at length scales equal to and less than the average major axis of the crystal population. This is significantly larger than what is obtained if a spherical crystal geometry would be assumed, and increases with deviation from sphericity. For the cordierite and biotite populations investigated in this research, Strauss hard-core ordering developed at length scales of up to ˜2.2 and 1.25 mm, respectively, which is almost 1 mm longer than
Valdes, Gilmer; Robinson, Clifford; Lee, Percy; Morel, Delphine; Low, Daniel; Iwamoto, Keisuke S.; Lamb, James M.
2015-04-01
Four-dimensional (4D) dose calculations for lung cancer radiotherapy have been technically feasible for a number of years but have not become standard clinical practice. The purpose of this study was to determine if clinically significant differences in tumor control probability (TCP) exist between 3D and 4D dose calculations so as to inform the decision whether 4D dose calculations should be used routinely for treatment planning. Radiotherapy plans for Stage I-II lung cancer were created for 8 patients. Clinically acceptable treatment plans were created with dose calculated on the end-exhale 4D computed tomography (CT) phase using a Monte Carlo algorithm. Dose was then projected onto the remaining 9 phases of 4D-CT using the Monte Carlo algorithm and accumulated onto the end-exhale phase using commercially available deformable registration software. The resulting dose-volume histograms (DVH) of the gross tumor volume (GTV), planning tumor volume (PTV), and PTV{sub setup} were compared according to target coverage and dose. The PTV{sub setup} was defined as a volume including the GTV and a margin for setup uncertainties but not for respiratory motion. TCPs resulting from these DVHs were estimated using a wide range of alphas, betas, and tumor cell densities. Differences of up to 5 Gy were observed between 3D and 4D calculations for a PTV with highly irregular shape. When the TCP was calculated using the resulting DVHs for fractionation schedules typically used in stereotactic body radiation therapy (SBRT), the TCP differed at most by 5% between 4D and 3D cases, and in most cases, it was by less than 1%. We conclude that 4D dose calculations are not necessary for most cases treated with SBRT, but they might be valuable for irregularly shaped target volumes. If 4D calculations are used, 4D DVHs should be evaluated on volumes that include margin for setup uncertainty but not respiratory motion.
Calculation of external dose from distributed source
Kocher, D.C.
1986-01-01
This paper discusses a relatively simple calculational method, called the point kernel method (Fo68), for estimating external dose from distributed sources that emit photon or electron radiations. The principles of the point kernel method are emphasized, rather than the presentation of extensive sets of calculations or tables of numerical results. A few calculations are presented for simple source geometries as illustrations of the method, and references and descriptions are provided for other caluclations in the literature. This paper also describes exposure situations for which the point kernel method is not appropriate and other, more complex, methods must be used, but these methods are not discussed in any detail.
NASA Astrophysics Data System (ADS)
Robert, Genevieve; Baker, Don R.; Rivers, Mark L.; Allard, Emilie; Larocque, Jeffery
2004-10-01
Three silicate glasses were hydrated at high pressure and then heated at atmospheric pressure to exsolve the water into bubbles and create foams. The bubble size distribution in these foams was measured by x-ray microtomography on the GSECARS BM-13 beamline at the Advanced Photon Source. The bubble area distributions were measured in two dimensions using the image slices produced from the microtomography and the software ImageJ. The bubble volume distributions were measured from the three-dimensional tomographic images with the BLOB3D software. We found that careful analysis of the microtomography data in both two and three dimensions was necessary to avoid the physically unrealistic, experimental artifact of identifying and counting many small bubbles whose surfaces were not defined by a septum of glass. When this artifact was avoided the foams demonstrated power-law distributions of bubble sizes in both two and three dimensions. Conversion of the power-law exponents for bubble areas measured in two dimensions to exponents for bubble volumes usually agreed with the measured three dimensional volume exponents. Furthermore, the power-law distributions for bubble volumes typically agree with multiple theories of bubble growth, all of which yield an exponent of 1 for the cumulative bubble volume distribution. The measured bubble volume distributions with exponents near 0.3 can be explained by diffusive growth as proposed by other authors, but distributions with exponents near 1.4 remain to be explained and are the subject of continuing research on the effects of water concentration and melt viscosity on foaming behavior.
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
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 (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
Fenrich, Keith K; Zhao, Ethan Y; Wei, Yuan; Garg, Anirudh; Rose, P Ken
2014-04-15
Isolating specific cellular and tissue compartments from 3D image stacks for quantitative distribution analysis is crucial for understanding cellular and tissue physiology under normal and pathological conditions. Current approaches are limited because they are designed to map the distributions of synapses onto the dendrites of stained neurons and/or require specific proprietary software packages for their implementation. To overcome these obstacles, we developed algorithms to Grow and Shrink Volumes of Interest (GSVI) to isolate specific cellular and tissue compartments from 3D image stacks for quantitative analysis and incorporated these algorithms into a user-friendly computer program that is open source and downloadable at no cost. The GSVI algorithm was used to isolate perivascular regions in the cortex of live animals and cell membrane regions of stained spinal motoneurons in histological sections. We tracked the real-time, intravital biodistribution of injected fluorophores with sub-cellular resolution from the vascular lumen to the perivascular and parenchymal space following a vascular microlesion, and mapped the precise distributions of membrane-associated KCC2 and gephyrin immunolabeling in dendritic and somatic regions of spinal motoneurons. Compared to existing approaches, the GSVI approach is specifically designed for isolating perivascular regions and membrane-associated regions for quantitative analysis, is user-friendly, and free. The GSVI algorithm is useful to quantify regional differences of stained biomarkers (e.g., cell membrane-associated channels) in relation to cell functions, and the effects of therapeutic strategies on the redistributions of biomolecules, drugs, and cells in diseased or injured tissues. Copyright © 2014 Elsevier B.V. All rights reserved.
ERIC Educational Resources Information Center
Smith, Garon C.; Hossain, Md Mainul
2017-01-01
Species TOPOS is a free software package for generating three-dimensional (3-D) topographic surfaces ("topos") for acid-base equilibrium studies. This upgrade adds 3-D species distribution topos to earlier surfaces that showed pH and buffer capacity behavior during titration and dilution procedures. It constructs topos by plotting…
Mu, Zhiping; Dobrucki, Lawrence W; Liu, Yi-Hwa
The imaging of distributed sources with near-field coded aperture (CA) remains extremely challenging and is broadly considered unsuitable for single-photon emission computerized tomography (SPECT). This study proposes a novel CA SPECT reconstruction approach and evaluates the feasibilities of imaging and reconstructing distributed hot sources and cold lesions using near-field CA collimation and iterative image reconstruction. Computer simulations were designed to compare CA and pinhole collimations in two-dimensional radionuclide imaging. Digital phantoms were created and CA images of the phantoms were reconstructed using maximum likelihood expectation maximization (MLEM). Errors and the contrast-to-noise ratio (CNR) were calculated and image resolution was evaluated. An ex vivo rat heart with myocardial infarction was imaged using a micro-SPECT system equipped with a custom-made CA module and a commercial 5-pinhole collimator. Rat CA images were reconstructed via the three-dimensional (3-D) MLEM algorithm developed for CA SPECT with and without correction for a large projection angle, and 5-pinhole images were reconstructed using the commercial software provided by the SPECT system. Phantom images of CA were markedly improved in terms of image quality, quantitative root-mean-squared error, and CNR, as compared to pinhole images. CA and pinhole images yielded similar image resolution, while CA collimation resulted in fewer noise artifacts. CA and pinhole images of the rat heart were well reconstructed and the myocardial perfusion defects could be clearly discerned from 3-D CA and 5-pinhole SPECT images, whereas 5-pinhole SPECT images suffered from severe noise artifacts. Image contrast of CA SPECT was further improved after correction for the large projection angle used in the rat heart imaging. The computer simulations and small-animal imaging study presented herein indicate that the proposed 3-D CA SPECT imaging and reconstruction approaches worked reasonably
Nadobny, Jacek; Wlodarczyk, Waldemar; Westhoff, Lothar; Gellermann, Johanna; Felix, Roland; Wust, Peter
2005-03-01
A magnetic resonance (MR)-compatible three-dimensional (3-D) hyperthermia applicator was developed and evaluated in the magnetic resonance (MR) tomograph Siemens MAGNETOM Symphony 1.5 T. Radiating elements of this applicator are 12 so-called water coated antenna (WACOA) modules, which are designed as specially shaped and adjustable dipole structures in hermetically closed cassettes that are filled by deionized water. The WACOA modules are arranged in the applicator frame in two transversal antenna subarrays, six antennas per subarray. As a standard load for the applicator an inhomogeneous phantom was fabricated. Details of applicator's realization are presented and a 3-D comparison of calculated and measured temperature data sets is made. A fair agreement is achieved that demonstrates the numerically supported applicator's ability of phase-defined 3-D pattern steering. Further refinement of numerical models and measuring methods is necessary. The applicator's design and the E-field calculations were performed using the finite-difference time-domain (FDTD) method. The calculation and optimization of temperature patterns was obtained using the finite element method (FEM). For MR temperature measurements the proton resonance frequency (PRF) method was used.
Kim, Hak Gu; Jeong, Hyunwook; Man Ro, Yong
2016-10-31
In computer-generated hologram (CGH) calculations, a diffraction pattern needs to be calculated from all points of a 3-D object, which requires a heavy computational cost. In this paper, we propose a novel fast computer-generated hologram calculation method using sparse fast Fourier transform. The proposed method consists of two steps. First, the sparse dominant signals of CGHs are measured by calculating a wavefront on a virtual plane between the object and the CGH plane. Second, the wavefront on CGH plane is calculated by using the measured sparsity with sparse Fresnel diffraction. Experimental results proved that the proposed method is much faster than existing works while it preserving the visual quality.
Modeling the crystal distribution of lead-sulfate in lead-acid batteries with 3D spatial resolution
NASA Astrophysics Data System (ADS)
Huck, Moritz; Badeda, Julia; Sauer, Dirk Uwe
2015-04-01
For the reliability of lead-acid batteries it is important to have an accurate prediction of its response to load profiles. A model for the lead-sulfate growth is presented, which is embedded in a physical-chemical model with 3D spatial resolution is presented which is used for analyzing the different mechanism influencing the cell response. One import factor is the chemical dissolution and precipitation of lead-sulfate, since its dissolution speed limits the charging reaction and the accumulation of indissolvable of lead-sulfate leads to capacity degradation. The cell performance/behavior is not only determined by the amount of the sulfate but also by the radii and distribution of the crystals. The presented model can be used to for an improved understanding of the interaction of the different mechanisms.
NASA Astrophysics Data System (ADS)
Bruno, Luigi
2016-12-01
With the present paper, the author proposes a fitting method for approximating experimental data retrieved from any full-field technique. Unlike most of the fitting procedures, the method works on data distributed on a surface of any shape, and the mathematical model is able to take into account of both the 3D shape of the surface and of the experimental quantity to be fitted. The paper reports all the mathematical steps necessary for applying the method, which was tested on two sets of experimental data obtained by an out-of-plane speckle interferometer working in two different conditions of noise. Experimental results showed the capability of the method to work in presence of high level of noise.
Azizan, Amizon; Büchs, Jochen
2017-01-01
Biotechnological development in shake flask necessitates vital engineering parameters e.g. volumetric power input, mixing time, gas liquid mass transfer coefficient, hydromechanical stress and effective shear rate. Determination and optimization of these parameters through experiments are labor-intensive and time-consuming. Computational Fluid Dynamics (CFD) provides the ability to predict and validate these parameters in bioprocess engineering. This work provides ample experimental data which are easily accessible for future validations to represent the hydrodynamics of the fluid flow in the shake flask. A non-invasive measuring technique using an optical fluorescence method was developed for shake flasks containing a fluorescent solution with a waterlike viscosity at varying filling volume (VL = 15 to 40 mL) and shaking frequency (n = 150 to 450 rpm) at a constant shaking diameter (do = 25 mm). The method detected the leading edge (LB) and tail of the rotating bulk liquid (TB) relative to the direction of the centrifugal acceleration at varying circumferential heights from the base of the shake flask. The determined LB and TB points were translated into three-dimensional (3D) circumferential liquid distribution plots. The maximum liquid height (Hmax) of the bulk liquid increased with increasing filling volume and shaking frequency of the shaking flask, as expected. The toroidal shapes of LB and TB are clearly asymmetrical and the measured TB differed by the elongation of the liquid particularly towards the torus part of the shake flask. The 3D liquid distribution data collected at varying filling volume and shaking frequency, comprising of LB and TB values relative to the direction of the centrifugal acceleration are essential for validating future numerical solutions using CFD to predict vital engineering parameters in shake flask.
Bahrami, Babak; Shahrbaf, Shirin; Mirzakouchaki, Behnam; Ghalichi, Farzan; Ashtiani, Mohammed; Martin, Nicolas
2014-04-01
To investigate, by means of FE analysis, the effect of surface roughness treatments on the distribution of stresses at the bone-implant interface in immediately loaded mandibular implants. An accurate, high resolution, digital replica model of bone structure (cortical and trabecular components) supporting an implant was created using CT scan data and image processing software (Mimics 13.1; Materialize, Leuven, Belgium). An anatomically accurate 3D model of a mandibular-implant complex was created using a professional 3D-CAD modeller (SolidWorks, DassaultSystèmes Solid Works Corp; 2011). Finite element models were created with one of the four roughness treatments on the implant fixture surface. Of these, three were surface treated to create a uniform coating determined by the coefficient of friction (μ); these were either (1) plasma sprayed or porous-beaded (μ=1.0), (2) sandblasted (μ=0.68) or (3) polished (μ=0.4). The fourth implant had a novel two-part surface roughness consisting of a coronal polished component (μ=0.4) interfacing with the cortical bone, and a body plasma treated surface component (μ=1) interfacing with the trabecular bone. Finite element stress analysis was carried out under vertical and lateral forces. This investigation showed that the type of surface treatment on the implant fixture affects the stress at the bone-implant interface of an immediately loaded implant complex. Von Mises stress data showed that the two-part surface treatment created the better stress distribution at the implant-bone interface. The results from this FE computational analysis suggest that the proposed two-part surface treatment for IL implants creates lower stresses than single uniform treatments at the bone-implant interface, which might decrease peri-implant bone loss. Future investigations should focus on mechanical and clinical validation of these FE results. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
The Radial Distribution of Star Formation in Galaxies at Z approximately 1 from the 3D-HST Survey
NASA Technical Reports Server (NTRS)
Nelson, Erica June; vanDokkum, Pieter G.; Momcheva, Ivelina; Brammer, Gabriel; Lundgren, Britt; Skelton, Rosalind E.; Whitaker, Katherine E.; DaCunha, Elisabete; Schreiber, Natascha Foerster; Franx, Marijn;
2013-01-01
The assembly of galaxies can be described by the distribution of their star formation as a function of cosmic time. Thanks to the WFC3 grism on the Hubble Space Telescope (HST) it is now possible to measure this beyond the local Universe. Here we present the spatial distribution of H emission for a sample of 54 strongly star-forming galaxies at z 1 in the 3D-HST Treasury survey. By stacking the H emission, we find that star formation occurred in approximately exponential distributions at z approximately 1, with a median Sersic index of n = 1.0 +/- 0.2. The stacks are elongated with median axis ratios of b/a = 0.58 +/- 0.09 in H consistent with (possibly thick) disks at random orientation angles. Keck spectra obtained for a subset of eight of the galaxies show clear evidence for rotation, with inclination corrected velocities of 90.330 km s(exp 1-). The most straightforward interpretation of our results is that star formation in strongly star-forming galaxies at z approximately 1 generally occurred in disks. The disks appear to be scaled-up versions of nearby spiral galaxies: they have EW(H alpha) at approximately 100 A out to the solar orbit and they have star formation surface densities above the threshold for driving galactic scale winds.
The Radial Distribution of Star Formation in Galaxies at z1 From The 3D-HST Survey
NASA Technical Reports Server (NTRS)
Nelson, Erica June; Dokkum, Pieter G. Van; Momcheva, Ivelina; Brammer, Gabriel; Lundgren, Britt; Skelton, Rosalind E.; Tease, Katherine Whitaker; Cunha, Elisabete Da; Schreiber, Natascha Forster; Franx, Marijn;
2013-01-01
The assembly of galaxies can be described by the distribution of their star formation as a function of cosmic time.Thanks to the WFC3 grism on the Hubble Space Telescope (HST) it is now possible to measure this beyond thelocal Universe. Here we present the spatial distribution of H emission for a sample of 54 strongly star-forming-galaxies at z1 in the 3D-HST Treasury survey. By stacking the Halpha emission, we find that star formation occurredin approximately exponential distributions at z1, with a median Sersic index of n=1.0 plus or minus 0.2. The stacks areelongated with median axis ratios of b/a 0.58 plus or minus 0.09 in Halpha consistent with (possibly thick) disks at randomorientation angles. Keck spectra obtained for a subset of eight of the galaxies show clear evidence for rotation, withinclination corrected velocities of 90-330 km per second. The most straightforward interpretation of our results is that starformation in strongly star-forming galaxies at z1 generally occurred in disks. The disks appear to be scaled-upversions of nearby spiral galaxies: they have EW(Halpha)100 Angstroms out to the solar orbit and they have star formation surface densities above the threshold for driving galactic scale winds.
THE RADIAL DISTRIBUTION OF STAR FORMATION IN GALAXIES AT z {approx} 1 FROM THE 3D-HST SURVEY
Nelson, Erica June; Van Dokkum, Pieter G.; Momcheva, Ivelina; Skelton, Rosalind E.; Leja, Joel; Brammer, Gabriel; Lundgren, Britt; Whitaker, Katherine E.; Da Cunha, Elisabete; Rix, Hans-Walter; Van der Wel, Arjen; Foerster Schreiber, Natascha; Wuyts, Stijn; Franx, Marijn; Fumagalli, Mattia; Labbe, Ivo; Patel, Shannon; Kriek, Mariska; Schmidt, Kasper B.
2013-01-20
The assembly of galaxies can be described by the distribution of their star formation as a function of cosmic time. Thanks to the WFC3 grism on the Hubble Space Telescope (HST) it is now possible to measure this beyond the local Universe. Here we present the spatial distribution of H{alpha} emission for a sample of 54 strongly star-forming galaxies at z {approx} 1 in the 3D-HST Treasury survey. By stacking the H{alpha} emission, we find that star formation occurred in approximately exponential distributions at z {approx} 1, with a median Sersic index of n = 1.0 {+-} 0.2. The stacks are elongated with median axis ratios of b/a = 0.58 {+-} 0.09 in H{alpha} consistent with (possibly thick) disks at random orientation angles. Keck spectra obtained for a subset of eight of the galaxies show clear evidence for rotation, with inclination corrected velocities of 90-330 km s{sup -1}. The most straightforward interpretation of our results is that star formation in strongly star-forming galaxies at z {approx} 1 generally occurred in disks. The disks appear to be 'scaled-up' versions of nearby spiral galaxies: they have EW(H{alpha}) {approx} 100 A out to the solar orbit and they have star formation surface densities above the threshold for driving galactic scale winds.
NASA Astrophysics Data System (ADS)
Lizar, J. C.; Santos, L. F.; Brandão, F. C.; Volpato, K. C.; Guimarães, F. S.; Pavoni, J. F.
2017-05-01
This study aims to evaluate the motion influence in the tridimensional dose distribution due to respiratory for IMRT breast planning technique. To simulate the breathing movement an oscillating platform was used. To simulate the breast, MAGIC-f phantoms were used. CT images of a static phantom were obtained and the IMRT treatment was planned based on them. One phantom was irradiated static in the platform and two other phantoms were irradiated while oscillating in the platform with amplitudes of 0.34 cm and 1.22 cm, the fourth phantom was used as reference in the MRI acquisition. The percentage of points approved in the 3D global gamma analyses (3%/3mm) when comparing the dose distribution of the static phantom with the oscillating ones was 91% for the 0.34cm amplitude and 62% for the 1.22 cm amplitude. Considering this result, the differences found in the dosimetric analyses for the oscillating amplitude of 0.34cm could be considered acceptable in a real treatment. The isodose distribution analyses showed a decrease of dose in the anterior breast region and an increase of dose on the posterior breast region, being these differences most pronounced for large amplitude motion.
NASA Astrophysics Data System (ADS)
Tari, H.; Scheidler, J. J.; Dapino, M. J.
2015-06-01
A reformulation of the Discrete Energy-Averaged model for the calculation of 3D hysteretic magnetization and magnetostriction of iron-gallium (Galfenol) alloys is presented in this paper. An analytical solution procedure based on an eigenvalue decomposition is developed. This procedure avoids the singularities present in the existing approximate solution by offering multiple local minimum energy directions for each easy crystallographic direction. This improved robustness is crucial for use in finite element codes. Analytical simplifications of the 3D model to 2D and 1D applications are also presented. In particular, the 1D model requires calculation for only one easy direction, while all six easy directions must be considered for general applications. Compared to the approximate solution procedure, it is shown that the resulting robustness comes at no expense for 1D applications, but requires almost twice the computational effort for 3D applications. To find model parameters, we employ the average of the hysteretic data, rather than anhysteretic curves, which would require additional measurements. An efficient optimization routine is developed that retains the dimensionality of the prior art. The routine decouples the parameters into exclusive sets, some of which are found directly through a fast preprocessing step to improve accuracy and computational efficiency. The effectiveness of the model is verified by comparison with existing measurement data.
WKB calculation of an epidemic outbreak distribution
NASA Astrophysics Data System (ADS)
Black, Andrew J.; McKane, Alan J.
2011-12-01
We calculate both the exponential and prefactor contributions in a WKB approximation of the master equation for a stochastic SIR model with highly oscillatory dynamics. Fixing the basic parameters of the model, we investigate how the outbreak distribution changes with the population size. We show that this distribution rapidly becomes highly non-Gaussian, acquiring large tails, indicating the presence of rare but large outbreaks, as the population is made smaller. The analytic results are found to be in excellent agreement with simulations until the systems become so small that the dynamics are dominated by fade-out of the disease.
NASA Technical Reports Server (NTRS)
Demuren, A. O.
1990-01-01
A multigrid method is presented for calculating turbulent jets in crossflow. Fairly rapid convergence is obtained with the k-epsilon turbulence model, but computations with a full Reynolds stress turbulence model (RSM) are not yet very efficient. Grid dependency tests show that there are slight differences between results obtained on the two finest grid levels. Computations using the RSM are significantly different from those with k-epsilon model and compare better to experimental data. Some work is still required to improve the efficiency of the computations with the RSM.
Jackson, Alicia R; Huang, Chun-Yuh C; Brown, Mark D; Gu, Wei Yong
2011-09-01
The intervertebral disc (IVD) receives important nutrients, such as glucose, from surrounding blood vessels. Poor nutritional supply is believed to play a key role in disc degeneration. Several investigators have presented finite element models of the IVD to investigate disc nutrition; however, none has predicted nutrient levels and cell viability in the disc with a realistic 3D geometry and tissue properties coupled to mechanical deformation. Understanding how degeneration and loading affect nutrition and cell viability is necessary for elucidating the mechanisms of disc degeneration and low back pain. The objective of this study was to analyze the effects of disc degeneration and static deformation on glucose distributions and cell viability in the IVD using finite element analysis. A realistic 3D finite element model of the IVD was developed based on mechano-electrochemical mixture theory. In the model, the cellular metabolic activities and viability were related to nutrient concentrations, and transport properties of nutrients were dependent on tissue deformation. The effects of disc degeneration and mechanical compression on glucose concentrations and cell density distributions in the IVD were investigated. To examine effects of disc degeneration, tissue properties were altered to reflect those of degenerated tissue, including reduced water content, fixed charge density, height, and endplate permeability. Two mechanical loading conditions were also investigated: a reference (undeformed) case and a 10% static deformation case. In general, nutrient levels decreased moving away from the nutritional supply at the disc periphery. Minimum glucose levels were at the interface between the nucleus and annulus regions of the disc. Deformation caused a 6.2% decrease in the minimum glucose concentration in the normal IVD, while degeneration resulted in an 80% decrease. Although cell density was not affected in the undeformed normal disc, there was a decrease in cell
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.
Rachev, Alexander; Taylor, W Robert; Vito, Raymond P
2013-07-01
Arteries manifest a remodeling response to long-term alterations in arterial pressure and blood flow by changing geometry, structure, and composition through processes driven by perturbations of the local stresses in the vascular wall from their baseline values. The objective of this study is twofold--to develop a general method for calculating the remodeling responses of an artery considered as a two-layered tube; and to provide results for adaptive and maladaptive remodeling of a coronary artery. By formulating an inverse problem of vascular mechanics, the geometrical dimensions and mechanical properties of an artery are calculated from a prescribed deformed configuration, stress field, structural stiffness, and applied load. As an illustrative example we consider a human LAD coronary artery in both a perfect and incomplete adaptive response to a sustained step-wise change in pressure and a maladaptive response due to impaired remodeling of adventitia. The results obtained show that adventitia plays an important role in vascular mechanics when an artery is subjected to high arterial pressure. In addition to its well-known short term function of preventing over-inflation of an artery, it seems reasonable to accept that the manner by which adventitia remodels in response to a chronic increase in pressure is essential for preserving normal arterial function or may lead to an increased risk of developing vascular disorders.
Guerin, P.; Baudron, A. M.; Lautard, J. J.
2006-07-01
This paper describes a new technique for determining the pin power in heterogeneous core calculations. It is based on a domain decomposition with overlapping sub-domains and a component mode synthesis technique for the global flux determination. Local basis functions are used to span a discrete space that allows fundamental global mode approximation through a Galerkin technique. Two approaches are given to obtain these local basis functions: in the first one (Component Mode Synthesis method), the first few spatial eigenfunctions are computed on each sub-domain, using periodic boundary conditions. In the second one (Factorized Component Mode Synthesis method), only the fundamental mode is computed, and we use a factorization principle for the flux in order to replace the higher order Eigenmodes. These different local spatial functions are extended to the global domain by defining them as zero outside the sub-domain. These methods are well-fitted for heterogeneous core calculations because the spatial interface modes are taken into account in the domain decomposition. Although these methods could be applied to higher order angular approximations - particularly easily to a SPN approximation - the numerical results we provide are obtained using a diffusion model. We show the methods' accuracy for reactor cores loaded with UOX and MOX assemblies, for which standard reconstruction techniques are known to perform poorly. Furthermore, we show that our methods are highly and easily parallelizable. (authors)
NASA Astrophysics Data System (ADS)
Tang, S.; Zhang, M. H.
2014-12-01
Large-scale forcing data (vertical velocities and advective tendencies) are important atmospheric fields to drive single-column models (SCM), cloud-resolving models (CRM) and large-eddy simulations (LES), but they are difficult to calculate accurately. The current 1-dimensional constrained variational analysis (1D CVA) method (Zhang and Lin, 1997) used by the Atmospheric Radiation Measurement (ARM) program is limited to represent the average of a sounding network domain. We extended the original 1D CVA algorithm into 3-dimensional along with other improvements, calculated gridded large-scale forcing data, apparent heating sources (Q1) and moisture sinks (Q2), and compared with 5 reanalyses: ERA-Interim, NCEP CFSR, MERRA, JRA55 and NARR for a mid-latitude spring cyclone case. The results from a case study for in March 3rd 2000 at the Southern Great Plain (SGP) show that reanalyses generally captured the structure of the mid-latitude cyclone, but they have serious biases in the 2nd order derivative terms (divergences and horizontal derivations) at regional scales of less than a few hundred kilometers. Our algorithm provides a set of atmospheric fields consistent with the observed constraint variables at the surface and top of the atmosphere better than reanalyses. The analyzed atmospheric fields can be used in SCM, CRM and LES to provide 3-dimensional dynamical forcing, or be used to evaluate reanalyses or model simulations.
Welsch, Goetz H; Zak, Lukas; Mamisch, Tallal C; Paul, Dominik; Lauer, Lars; Mauerer, Andreas; Marlovits, Stefan; Trattnig, Siegfried
2011-01-01
To evaluate a new isotropic 3D proton-density, turbo-spin-echo sequence with variable flip-angle distribution (PD-SPACE) sequence compared to an isotropic 3D true-fast-imaging with steady-state-precession (True-FISP) sequence and 2D standard MR sequences with regard to the new 3D magnetic resonance observation of cartilage repair tissue (MOCART) score. Sixty consecutive MR scans on 37 patients (age: 32.8 ± 7.9 years) after matrix-associated autologous chondrocyte transplantation (MACT) of the knee were prospectively included. The 3D MOCART score was assessed using the standard 2D sequences and the multiplanar-reconstruction (MPR) of both isotropic sequences. Statistical, Bonferroni-corrected correlation as well as subjective quality analysis were performed. The correlation of the different sequences was significant for the variables defect fill, cartilage interface, bone interface, surface, subchondral lamina, chondral osteophytes, and effusion (Pearson coefficients 0.514-0.865). Especially between the standard sequences and the 3D True-FISP sequence, the variables structure, signal intensity, subchondral bone, and bone marrow edema revealed lower, not significant, correlation values (0.242-0.383). Subjective quality was good for all sequences (P ≥ 0.05). Artifacts were most often visible on the 3D True-FISP sequence (P < 0.05). Different isotropic sequences can be used for the 3D evaluation of cartilage repair with the benefits of isotropic 3D MRI, MPR, and a significantly reduced scan time, where the 3D PD-SPACE sequence reveals the best results. Copyright © 2010 Wiley-Liss, Inc.
NASA Technical Reports Server (NTRS)
Stremel, Paul M.
1995-01-01
A method has been developed to accurately compute the viscous flow in three-dimensional (3-D) enclosures. This method is the 3-D extension of a two-dimensional (2-D) method developed for the calculation of flow over airfoils. The 2-D method has been tested extensively and has been shown to accurately reproduce experimental results. As in the 2-D method, the 3-D method provides for the non-iterative solution of the incompressible Navier-Stokes equations by means of a fully coupled implicit technique. The solution is calculated on a body fitted computational mesh incorporating a staggered grid methodology. In the staggered grid method, the three components of vorticity are defined at the centers of the computational cell sides, while the velocity components are defined as normal vectors at the centers of the computational cell faces. The staggered grid orientation provides for the accurate definition of the vorticity components at the vorticity locations, the divergence of vorticity at the mesh cell nodes and the conservation of mass at the mesh cell centers. The solution is obtained by utilizing a fractional step solution technique in the three coordinate directions. The boundary conditions for the vorticity and velocity are calculated implicitly as part of the solution. The method provides for the non-iterative solution of the flow field and satisfies the conservation of mass and divergence of vorticity to machine zero at each time step. To test the method, the calculation of simple driven cavity flows have been computed. The driven cavity flow is defined as the flow in an enclosure driven by a moving upper plate at the top of the enclosure. To demonstrate the ability of the method to predict the flow in arbitrary cavities, results will he shown for both cubic and curved cavities.
NASA Astrophysics Data System (ADS)
He, J.
2015-12-01
Magnetic reconnection within current sheet has been regarded as one of the crucial dissipation and heating processes of coherent structures in the solar wind turbulence. Counter-streaming of ions is an important phenomenon in the reconnection exhaust region ranged from the ion diffusion region to the extended outflow region. It has been suggested by theoretical and numerical models that the ions are going to be picked up by the ejecting magnetic field and show larger T_perpendicular than T_parallel, if the guide field is strong enough (in other word, the shear angle is relatively low). The pick-up behavior seems to favor the heating of heavy ions with high mass-to-charge ratio, since the high M/Q ions have larger gyro-period/transit-time and tend to be non-adiabatic more easily. The above statements from theoretical models have not been thoroughly testified in the solar wind observations, though the changes in total temperature and 1D reduced velocity distribution function had been studied. Until now, it remains unclear about the difference of full 3D velocity distribution for the proton and helium ions between the upstream and the exhaust regions. Here, we will analyze the plasma measurement data from WIND/3DP to explore and compare the parallel and perpendicular heating effect of different species of ions. As a preliminary result, the proton is found to show bi-directional streams in its velocity distribution in some reconnection exhaust regions. The thermalization of the counter-streaming protons will be presented. The relation between proton T_parallel/T_perpendicular and guide field strength (or shear angle) will be studied. The velocity distributions of helium ions will be illustrated, which shows the difference of heating effect between different M/Q ratios.
Quasi 3D dosimetry (EPID, conventional 2D/3D detector matrices)
NASA Astrophysics Data System (ADS)
Bäck, A.
2015-01-01
Patient specific pretreatment measurement for IMRT and VMAT QA should preferably give information with a high resolution in 3D. The ability to distinguish complex treatment plans, i.e. treatment plans with a difference between measured and calculated dose distributions that exceeds a specified tolerance, puts high demands on the dosimetry system used for the pretreatment measurements and the results of the measurement evaluation needs a clinical interpretation. There are a number of commercial dosimetry systems designed for pretreatment IMRT QA measurements. 2D arrays such as MapCHECK® (Sun Nuclear), MatriXXEvolution (IBA Dosimetry) and OCTAVIOUS® 1500 (PTW), 3D phantoms such as OCTAVIUS® 4D (PTW), ArcCHECK® (Sun Nuclear) and Delta4 (ScandiDos) and software for EPID dosimetry and 3D reconstruction of the dose in the patient geometry such as EPIDoseTM (Sun Nuclear) and Dosimetry CheckTM (Math Resolutions) are available. None of those dosimetry systems can measure the 3D dose distribution with a high resolution (full 3D dose distribution). Those systems can be called quasi 3D dosimetry systems. To be able to estimate the delivered dose in full 3D the user is dependent on a calculation algorithm in the software of the dosimetry system. All the vendors of the dosimetry systems mentioned above provide calculation algorithms to reconstruct a full 3D dose in the patient geometry. This enables analyzes of the difference between measured and calculated dose distributions in DVHs of the structures of clinical interest which facilitates the clinical interpretation and is a promising tool to be used for pretreatment IMRT QA measurements. However, independent validation studies on the accuracy of those algorithms are scarce. Pretreatment IMRT QA using the quasi 3D dosimetry systems mentioned above rely on both measurement uncertainty and accuracy of calculation algorithms. In this article, these quasi 3D dosimetry systems and their use in patient specific pretreatment IMRT
NASA Astrophysics Data System (ADS)
Ou, Chenghua; Li, ChaoChun; Ma, Zhonggao
2016-10-01
A water-bearing carbonate gas reservoir is an important natural gas resource being developed worldwide. Due to the long-term water/rock/gas interaction during geological evolution, complex gas/water distribution has formed under the superposed effect of sedimentary facies, reservoir space facies and gravity difference of fluid facies. In view of these challenges, on the basis of the conventional three-stage modeling method, this paper presents a modelling method controlled by four-stage facies to develop 3D model of a water-bearing carbonate gas reservoir. Key to this method is the reservoir property modelling controlled by two-stage facies, and the fluid property modelling controlled by another two-stage facies. The prerequisite of this method is a reliable database obtained from solid geological investigation. On the basis of illustrating the principles of the modelling method controlled by four-stage facies, this paper further implements systematically modeling of the heterogeneous gas/water distribution of the Longwangmiao carbonate formation in the Moxi-Gaoshiti area, Sichuan basin, China.
NASA Astrophysics Data System (ADS)
Giles, B. L.; Pollock, C. J.; Avanov, L. A.; Barrie, A. C.; Burch, J. L.; Chandler, M. O.; Clark, G. B.; Coffey, V. N.; Dickson, C.; Dorelli, J.; Ergun, R. E.; Fuselier, S. A.; Gershman, D. J.; Gliese, U.; Holland, M. P.; Jacques, A. D.; Kreisler, S.; Lavraud, B.; MacDonald, E.; Mauk, B.; Moore, T. E.; Mukai, T.; Nakamura, R.; Paterson, W. R.; Rager, A. C.; Saito, Y.; Salo, C.; Sauvaud, J. A.; Torbert, R. B.; Vinas, A. F.; Yokota, S.
2015-12-01
The primary focus of the Magnetospheric Multiscale (MMS) mission, launched in March 2015, is magnetic reconnection and associated processes. Understanding hinges critically on the kinetic physics that allows reconnection to take place. The Fast Plasma Investigation (FPI) provides electron and ion distribution functions at 4.5s cadence and, for select periods of time, at cadences of 30ms for electrons and 150ms for ions. These select time periods are chosen after in situ acquisition based on inspection of the low resolution data. Thus the FPI provides, independent of spacecraft spin rate, the time resolution needed to resolve the small, fast-moving reconnection diffusion regions. The first mission phase focuses on the dayside magnetopause and this presentation is intended to demonstrate the capabilities of FPI to resolve the important spatial scales relevant to the reconnection process. Magnetopause and other boundary crossings will be examined and the phase-space trajectories identified at the tetrahedral satellite locations through analysis of the 3D distribution functions.
A 3-D hp finite/infinite element method to calculate power deposition in the human head.
Xue, Dong; Demkowicz, Leszek; Hao, Ling
2007-04-01
The electromagnetic power deposition and transfer properties of a G1 continuous head model reconstructed from magnetic resonance imaging (MRI) data are investigated by using the coupled hp finite/infinite element (FE/IE) method. The discretization error is controlled by a self-adaptive process driven by an explicit a posteriori error estimate. Based on the benchmark problem of reproducing the Mie series solution, the scattering of a plane wave on the curvilinear head model is used to evaluate the hp FE/IE approach and calibrate the error bound. The radiation pattern from a short dipole antenna modeling a cell phone, is analyzed in terms of the level and distribution of the specific absorption rates (SAR). The numerical experiments show that the hybrid hp FE/IE implementation is a competitive tool for accurate assessment of human electromagnetic exposure.
Valdes, Gilmer; Robinson, Clifford; Lee, Percy; Morel, Delphine; Low, Daniel; Iwamoto, Keisuke S; Lamb, James M
2015-01-01
Four-dimensional (4D) dose calculations for lung cancer radiotherapy have been technically feasible for a number of years but have not become standard clinical practice. The purpose of this study was to determine if clinically significant differences in tumor control probability (TCP) exist between 3D and 4D dose calculations so as to inform the decision whether 4D dose calculations should be used routinely for treatment planning. Radiotherapy plans for Stage I-II lung cancer were created for 8 patients. Clinically acceptable treatment plans were created with dose calculated on the end-exhale 4D computed tomography (CT) phase using a Monte Carlo algorithm. Dose was then projected onto the remaining 9 phases of 4D-CT using the Monte Carlo algorithm and accumulated onto the end-exhale phase using commercially available deformable registration software. The resulting dose-volume histograms (DVH) of the gross tumor volume (GTV), planning tumor volume (PTV), and PTVsetup were compared according to target coverage and dose. The PTVsetup was defined as a volume including the GTV and a margin for setup uncertainties but not for respiratory motion. TCPs resulting from these DVHs were estimated using a wide range of alphas, betas, and tumor cell densities. Differences of up to 5Gy were observed between 3D and 4D calculations for a PTV with highly irregular shape. When the TCP was calculated using the resulting DVHs for fractionation schedules typically used in stereotactic body radiation therapy (SBRT), the TCP differed at most by 5% between 4D and 3D cases, and in most cases, it was by less than 1%. We conclude that 4D dose calculations are not necessary for most cases treated with SBRT, but they might be valuable for irregularly shaped target volumes. If 4D calculations are used, 4D DVHs should be evaluated on volumes that include margin for setup uncertainty but not respiratory motion. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier
NASA Astrophysics Data System (ADS)
Gerzen, Tatjana; Wilken, Volker; Jakowski, Norbert; Hoque, Mainul M.
2013-04-01
New methods to generate maps of the F2 layer peak electron density of the ionosphere (NmF2) and to reconstruct the ionospheric 3D electron density distribution will be presented. For validation, reconstructed NmF2 maps will be compared with peak electron density measurements from independent ionosonde stations. The ionosphere is the ionized part of the upper Earth's atmosphere lying between about 50 km and 1000 km above the Earth's surface. From the applications perspective the electron density, Ne, is certainly one of the most important parameters of the ionosphere because of its strong impact on radio signal propagation. Especially the critical frequency, foF2, which is related to the F2 layer peak electron density, NmF2, according to the equation NmF2-m3 = 1.24 ? 1010(foF2-MHz)2 and builds the lower limit for the maximum usable frequency MUF, is of particular interest with regard to the HF radio communication applications. In a first order approximation the ionospheric delay of transionospheric radio waves of frequency f is proportional to 1-f2 and to the integral of the electron density (total electron content - TEC) along the ray path. Thus, the information about the total electron content along the receiver-to-satellite ray path can be obtained from the dual frequency measurements permanently transmitted by GNSS satellites. As data base for our reconstruction approaches we use the vertical sounding measurements of the ionosonde stations providing foF2 and routinely generated TEC maps in SWACI (http://swaciweb.dlr.de) at DLR Neustrelitz. The basic concept of our approach is the following one: To reconstruct NmF2 maps we assimilate the ionosonde data into the global Neustrelitz F2 layer Peak electron Density Model (NPDM) by means of a successive corrections method. The TEC maps are produced by assimilating actual ground based GPS measurements providing TEC into an operational version of Neustrelitz TEC Model (NTCM). Finally, the derived NmF2 and TEC maps in
Wemhoff, A P; Burnham, A K
2006-04-05
Cross-comparison of the results of two computer codes for the same problem provides a mutual validation of their computational methods. This cross-validation exercise was performed for LLNL's ALE3D code and AKTS's Thermal Safety code, using the thermal ignition of HMX in two standard LLNL cookoff experiments: the One-Dimensional Time to Explosion (ODTX) test and the Scaled Thermal Explosion (STEX) test. The chemical kinetics model used in both codes was the extended Prout-Tompkins model, a relatively new addition to ALE3D. This model was applied using ALE3D's new pseudospecies feature. In addition, an advanced isoconversional kinetic approach was used in the AKTS code. The mathematical constants in the Prout-Tompkins code were calibrated using DSC data from hermetically sealed vessels and the LLNL optimization code Kinetics05. The isoconversional kinetic parameters were optimized using the AKTS Thermokinetics code. We found that the Prout-Tompkins model calculations agree fairly well between the two codes, and the isoconversional kinetic model gives very similar results as the Prout-Tompkins model. We also found that an autocatalytic approach in the beta-delta phase transition model does affect the times to explosion for some conditions, especially STEX-like simulations at ramp rates above 100 C/hr, and further exploration of that effect is warranted.
NASA Astrophysics Data System (ADS)
Mann, P.; Saito, N.; Lang, C.; Runz, A.; Johnen, W.; Witte, M.; Schmitt, D.; Karger, C. P.
2017-05-01
This study aims to evaluate an in-house developed 4D dose calculation algorithm that uses Calypso motion tracking data and to compare the results against 3D polymer gel dosimetry measurements. For this, a cylindrical water phantom was constructed that allows to insert (i) the polymer gel, (ii) a PinPoint ® ionization chamber and (iii) Calypso beacons™ for motion tracking. A treatment plan covering a gel flask in the center of the static phantom plus a 1 mm margin homogeneously with dose was generated. During irradiation, however, the phantom was moved periodically by means of a robot with a peak-to-peak amplitude of 2.5 cm. The results of the 4D dose calculations show good agreement with the gel-dosimetric measurements in most of the volume. Remaining small deviations have to be evaluated in further experiments. The developed experimental setup allows for 3D-dosimetric validation of 4D dose calculations algorithms prior to application in patients.
Park, J; Lee, J; Kim, H; Kim, I; Ye, S
2015-06-15
Purpose: To evaluate the effect of a tungsten eye-shield on the dose distribution of a patient. Methods: A 3D scanner was used to extract the dimension and shape of a tungsten eye-shield in the STL format. Scanned data was transferred into a 3D printer. A dummy eye shield was then produced using bio-resin (3D systems, VisiJet M3 Proplast). For a patient with mucinous carcinoma, the planning CT was obtained with the dummy eye-shield placed on the patient’s right eye. Field shaping of 6 MeV was performed using a patient-specific cerrobend block on the 15 x 15 cm{sup 2} applicator. The gantry angle was 330° to cover the planning target volume near by the lens. EGS4/BEAMnrc was commissioned from our measurement data from a Varian 21EX. For the CT-based dose calculation using EGS4/DOSXYZnrc, the CT images were converted to a phantom file through the ctcreate program. The phantom file had the same resolution as the planning CT images. By assigning the CT numbers of the dummy eye-shield region to 17000, the real dose distributions below the tungsten eye-shield were calculated in EGS4/DOSXYZnrc. In the TPS, the CT number of the dummy eye-shield region was assigned to the maximum allowable CT number (3000). Results: As compared to the maximum dose, the MC dose on the right lens or below the eye shield area was less than 2%, while the corresponding RTP calculated dose was an unrealistic value of approximately 50%. Conclusion: Utilizing a 3D scanner and a 3D printer, a dummy eye-shield for electron treatment can be easily produced. The artifact-free CT images were successfully incorporated into the CT-based Monte Carlo simulations. The developed method was useful in predicting the realistic dose distributions around the lens blocked with the tungsten shield.
NASA Astrophysics Data System (ADS)
Raithatha, Bansri; McCaffrey, Kenneth; Walker, Richard; Brown, Richard; Pickering, Giles
2013-04-01
Hydrocarbon reservoirs commonly contain an array of fine-scale structures that control fluid flow in the subsurface, such as polyphase fracture networks and small-scale fault zones. These structures are unresolvable using seismic imaging and therefore outcrop-based studies have been used as analogues to characterize fault and fracture networks and assess their impact on fluid flow in the subsurface. To maximize recovery and enhance production, it is essential to understand the geometry, physical properties, and distribution of these structures in 3D. Here we present field data and terrestrial LIDAR-derived 3D, photo-realistic virtual outcrops of fault zones at a range of displacement scales (0.001- 4.5 m) within a volcaniclastic sand- and basaltic lava unit sequence in the Faroe Islands. Detailed field observations were used to constrain the virtual outcrop dataset, and a workflow has been developed to build a discrete fracture network (DFN) models in GOCAD® from these datasets. Model construction involves three main stages: (1) Georeferencing and processing of LIDAR datasets; (2) Structural interpretation to discriminate between faults, fractures, veins, and joint planes using CAD software and RiSCAN Pro; and (3) Building a 3D DFN in GOCAD®. To test the validity of this workflow, we focus here on a 4.5 m displacement strike-slip fault zone that displays a complex polymodal fracture network in the inter-layered basalt-volcaniclastic sequence, which is well-constrained by field study. The DFN models support our initial field-based hypothesis that fault zone geometry varies with increasing displacement through volcaniclastic units. Fracture concentration appears to be greatest in the upper lava unit, decreases into the volcaniclastic sediments, and decreases further into the lower lava unit. This distribution of fractures appears to be related to the width of the fault zone and the amount of fault damage on the outcrop. For instance, the fault zone is thicker in
Crookshank, Meghan C.; Beek, Maarten; Hardisty, Michael R.; Schemitsch, Emil H.
2014-01-01
Objective This study presents and evaluates a semi-automated algorithm for quantifying malalignment in complex femoral shaft fractures from a single intraoperative cone-beam CT (CBCT) image of the fractured limb. Methods CBCT images were acquired of complex comminuted diaphyseal fractures created in 9 cadaveric femora (27 cases). Scans were segmented using intensity-based thresholding, yielding image stacks of the proximal, distal and comminuted bone. Semi-deformable and rigid affine registrations to an intact femur atlas (synthetic or cadaveric-based) were performed to transform the distal fragment to its neutral alignment. Leg length was calculated from the volume of bone within the comminution fragment. The transformations were compared to the physical input malalignments. Results Using the synthetic atlas, translations were within 1.71 ± 1.08 mm (medial/lateral) and 2.24 ± 2.11 mm (anterior/posterior). The varus/valgus, flexion/extension and periaxial rotation errors were 3.45 ± 2.6°, 1.86 ± 1.5° and 3.4 ± 2.0°, respectively. The cadaveric-based atlas yielded similar results in medial/lateral and anterior/posterior translation (1.73 ± 1.28 mm and 2.15 ± 2.13 mm, respectively). Varus/valgus, flexion/extension and periaxial rotation errors were 2.3 ± 1.3°, 2.0 ± 1.6° and 3.4 ± 2.0°, respectively. Leg length errors were 1.41 ± 1.01 mm (synthetic) and 1.26 ± 0.94 mm (cadaveric). The cadaveric model demonstrated a small improvement in flexion/extension and the synthetic atlas performed slightly faster (6 min 24 s ± 50 s versus 8 min 42 s ± 2 min 25 s). Conclusions This atlas-based algorithm quantified malalignment in complex femoral shaft fractures within clinical tolerances from a single CBCT image of the fractured limb. PMID:24720491
Battisti, Sofia; Guida, Francesco Maria; Coppa, Federica; Vaccaro, Donata M; Santini, Daniele; Tonini, Giuseppe; Zobel, Bruno B; Semelka, Richard C
2014-10-01
The purpose of this study was to describe modification of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) distributions in breast cancer patients after aromatase inhibitor (AI) therapy using computed tomography (CT) volumetric measurement of abdominal body fat distribution. Sixty-four consecutive patients who were receiving adjuvant AI therapy were included in this study. Patients were evaluated using CT before and after at least 6 months of AI therapy with imaging follow-up of 4.3 ± 2.2 years. Abdominal fat distribution was automatically calculated using a workstation that obtained total abdominal adipose tissue (TAAT) area (mm(3)). SAT was manually segmented and VAT was determined as TAAT - SAT. Percentages were calculated for change of TAAT, VAT, and SAT. VAT/SAT ratio was calculated. Percentage of TAAT after AI therapy was increased by a mean of 9.1% from baseline (16,280.3 ± 6953.3 mm(3)) to (17,763.6 ± 6850.8 mm(3)). Two groups of patients were observed; those with an increase in TAAT and those with a decrease. Modification of VAT/SAT ratio was observed (from 1.38 to 1.69) in all subjects, reflecting a relative increased volume of VAT (mean, 18%) and slight mean reduction of SAT (mean 1.9%). In our study, therapy with AI in breast cancer patients was accompanied with a change in fat distribution to relatively greater VAT/SAT ratio in patients, regardless of whether they gained or lost weight after therapy. Because this pattern of fat distribution is associated with metabolic disorders, attention must be paid to these clinical manifestations in patients during their follow-up management. Copyright © 2014 Elsevier Inc. All rights reserved.
Yamanel, Kivanç; Caglar, Alper; Gülsahi, Kamran; Ozden, Utku Ahmet
2009-11-01
To reduce loss of tooth tissue and to improve esthetic results, inlay and onlay restorations are good treatment choices for extensive cavities in posterior teeth. The aim of this paper was to evaluate, by means of three-dimensional finite element analysis, the effects of restorative material and cavity design on stress distribution in the tooth structures and restorative materials. Two different nanofilled composites and two different all-ceramic materials were used in this study. A permanent molar tooth was modeled with enamel and dentin structures. 3-D inlay and onlay cavity designs were created. Von Mises, compressive, and tensile stresses on the restorative materials, core materials, enamel, and dentin were evaluated separately. On the effect of restorative material, results showed that in the case of materials with low elastic moduli, more stress was transferred to the tooth structures. Therefore, compared to the nanofilled composites, the all-ceramic inlay and onlay materials tested transferred less stress to the tooth structures. On the effect of cavity design, the onlay design was more efficacious in protecting the tooth structures than the inlay design.
Hussein, Mostafa Omran
2013-08-01
This study was accomplished to assess the biomechanical state of different retaining methods of bar implant-overdenture. Two 3D finite element models were designed. The first model included implant overdenture retained by Hader-clip attachment, while the second model included two extracoronal resilient attachment (ERA) studs added distally to Hader splint bar. A non-linear frictional contact type was assumed between overdentures and mucosa to represent sliding and rotational movements among different attachment components. A 200 N was applied at the molar region unilaterally and perpendicular to the occlusal plane. Additionally, the mandible was restrained at their ramus ends. The maximum equivalent stress and strain (von Mises) were recorded and analyzed at the bone-implant interface level. The values of von Mises stress and strain of the first model at bone-implant interface were higher than their counterparts of the second model. Stress concentration and high value of strain were recognized surrounding implant of the unloaded side in both models. There were different patterns of stress-strain distribution at bone-implant interface between the studied attachment designs. Hader bar-clip attachment showed better biomechanical behavior than adding ERA studs distal to hader bar.
2013-01-01
PURPOSE This study was accomplished to assess the biomechanical state of different retaining methods of bar implant-overdenture. MATERIALS AND METHODS Two 3D finite element models were designed. The first model included implant overdenture retained by Hader-clip attachment, while the second model included two extracoronal resilient attachment (ERA) studs added distally to Hader splint bar. A non-linear frictional contact type was assumed between overdentures and mucosa to represent sliding and rotational movements among different attachment components. A 200 N was applied at the molar region unilaterally and perpendicular to the occlusal plane. Additionally, the mandible was restrained at their ramus ends. The maximum equivalent stress and strain (von Mises) were recorded and analyzed at the bone-implant interface level. RESULTS The values of von Mises stress and strain of the first model at bone-implant interface were higher than their counterparts of the second model. Stress concentration and high value of strain were recognized surrounding implant of the unloaded side in both models. CONCLUSION There were different patterns of stress-strain distribution at bone-implant interface between the studied attachment designs. Hader bar-clip attachment showed better biomechanical behavior than adding ERA studs distal to hader bar. PMID:24049576
Xu, Zhongnan; Joshi, Yogesh V; Raman, Sumathy; Kitchin, John R
2015-04-14
We validate the usage of the calculated, linear response Hubbard U for evaluating accurate electronic and chemical properties of bulk 3d transition metal oxides. We find calculated values of U lead to improved band gaps. For the evaluation of accurate reaction energies, we first identify and eliminate contributions to the reaction energies of bulk systems due only to changes in U and construct a thermodynamic cycle that references the total energies of unique U systems to a common point using a DFT + U(V) method, which we recast from a recently introduced DFT + U(R) method for molecular systems. We then introduce a semi-empirical method based on weighted DFT/DFT + U cohesive energies to calculate bulk oxidation energies of transition metal oxides using density functional theory and linear response calculated U values. We validate this method by calculating 14 reactions energies involving V, Cr, Mn, Fe, and Co oxides. We find up to an 85% reduction of the mean average error (MAE) compared to energies calculated with the Perdew-Burke-Ernzerhof functional. When our method is compared with DFT + U with empirically derived U values and the HSE06 hybrid functional, we find up to 65% and 39% reductions in the MAE, respectively.
Xu, Zhongnan; Kitchin, John R.; Joshi, Yogesh V.; Raman, Sumathy
2015-04-14
We validate the usage of the calculated, linear response Hubbard U for evaluating accurate electronic and chemical properties of bulk 3d transition metal oxides. We find calculated values of U lead to improved band gaps. For the evaluation of accurate reaction energies, we first identify and eliminate contributions to the reaction energies of bulk systems due only to changes in U and construct a thermodynamic cycle that references the total energies of unique U systems to a common point using a DFT + U(V ) method, which we recast from a recently introduced DFT + U(R) method for molecular systems. We then introduce a semi-empirical method based on weighted DFT/DFT + U cohesive energies to calculate bulk oxidation energies of transition metal oxides using density functional theory and linear response calculated U values. We validate this method by calculating 14 reactions energies involving V, Cr, Mn, Fe, and Co oxides. We find up to an 85% reduction of the mean average error (MAE) compared to energies calculated with the Perdew-Burke-Ernzerhof functional. When our method is compared with DFT + U with empirically derived U values and the HSE06 hybrid functional, we find up to 65% and 39% reductions in the MAE, respectively.
NASA Astrophysics Data System (ADS)
Xu, Zhongnan; Joshi, Yogesh V.; Raman, Sumathy; Kitchin, John R.
2015-04-01
We validate the usage of the calculated, linear response Hubbard U for evaluating accurate electronic and chemical properties of bulk 3d transition metal oxides. We find calculated values of U lead to improved band gaps. For the evaluation of accurate reaction energies, we first identify and eliminate contributions to the reaction energies of bulk systems due only to changes in U and construct a thermodynamic cycle that references the total energies of unique U systems to a common point using a DFT + U(V ) method, which we recast from a recently introduced DFT + U(R) method for molecular systems. We then introduce a semi-empirical method based on weighted DFT/DFT + U cohesive energies to calculate bulk oxidation energies of transition metal oxides using density functional theory and linear response calculated U values. We validate this method by calculating 14 reactions energies involving V, Cr, Mn, Fe, and Co oxides. We find up to an 85% reduction of the mean average error (MAE) compared to energies calculated with the Perdew-Burke-Ernzerhof functional. When our method is compared with DFT + U with empirically derived U values and the HSE06 hybrid functional, we find up to 65% and 39% reductions in the MAE, respectively.
Calculation of dose distribution above contaminated soil
NASA Astrophysics Data System (ADS)
Kuroda, Junya; Tenzou, Hideki; Manabe, Seiya; Iwakura, Yukiko
2017-07-01
The purpose of this study was to assess the relationship between altitude and the distribution of the ambient dose rate in the air over soil decontamination area by using PHITS simulation code. The geometry configuration was 1000 m ×1000 m area and 1m in soil depth and 100m in altitude from the ground to simulate the area of residences or a school grounds. The contaminated region is supposed to be uniformly contaminated by Cs-137 γ radiation sources. The air dose distribution and space resolution was evaluated for flux of the gamma rays at each altitude, 1, 5, 10, and 20m. The effect of decontamination was calculated by defining sharpness S. S was the ratio of an average flux and a flux at the center of denomination area in each altitude. The suitable flight altitude of the drone is found to be less than 15m above a residence and 31m above a school grounds to confirm the decontamination effect. The calculation results can be a help to determine a flight planning of a drone to minimize the clash risk.
Hoffman, E.L.; Ammerman, D.J.
1995-04-01
A series of tests investigating dynamic pulse buckling of a cylindrical shell under axial impact is compared to several 2D and 3D finite element simulations of the event. The purpose of the work is to investigate the performance of various analysis codes and element types on a problem which is applicable to radioactive material transport packages, and ultimately to develop a benchmark problem to qualify finite element analysis codes for the transport package design industry. Four axial impact tests were performed on 4 in-diameter, 8 in-long, 304 L stainless steel cylinders with a 3/16 in wall thickness. The cylinders were struck by a 597 lb mass with an impact velocity ranging from 42.2 to 45.1 ft/sec. During the impact event, a buckle formed at each end of the cylinder, and one of the two buckles became unstable and collapsed. The instability occurred at the top of the cylinder in three tests and at the bottom in one test. Numerical simulations of the test were performed using the following codes and element types: PRONTO2D with axisymmetric four-node quadrilaterals; PRONTO3D with both four-node shells and eight-node hexahedrons; and ABAQUS/Explicit with axisymmetric two-node shells and four-node quadrilaterals, and 3D four-node shells and eight-node hexahedrons. All of the calculations are compared to the tests with respect to deformed shape and impact load history. As in the tests, the location of the instability is not consistent in all of the calculations. However, the calculations show good agreement with impact load measurements with the exception of an initial load spike which is proven to be the dynamic response of the load cell to the impact. Finally, the PRONIT02D calculation is compared to the tests with respect to strain and acceleration histories. Accelerometer data exhibited good qualitative agreement with the calculations. The strain comparisons show that measurements are very sensitive to gage placement.
NASA Astrophysics Data System (ADS)
Wang, Jin; Zhang, Cao; Katz, Joseph
2016-11-01
A PIV based method to reconstruct the volumetric pressure field by direct integration of the 3D material acceleration directions has been developed. Extending the 2D virtual-boundary omni-directional method (Omni2D, Liu & Katz, 2013), the new 3D parallel-line omni-directional method (Omni3D) integrates the material acceleration along parallel lines aligned in multiple directions. Their angles are set by a spherical virtual grid. The integration is parallelized on a Tesla K40c GPU, which reduced the computing time from three hours to one minute for a single realization. To validate its performance, this method is utilized to calculate the 3D pressure fields in isotropic turbulence and channel flow using the JHU DNS Databases (http://turbulence.pha.jhu.edu). Both integration of the DNS acceleration as well as acceleration from synthetic 3D particles are tested. Results are compared to other method, e.g. solution to the Pressure Poisson Equation (e.g. PPE, Ghaemi et al., 2012) with Bernoulli based Dirichlet boundary conditions, and the Omni2D method. The error in Omni3D prediction is uniformly low, and its sensitivity to acceleration errors is local. It agrees with the PPE/Bernoulli prediction away from the Dirichlet boundary. The Omni3D method is also applied to experimental data obtained using tomographic PIV, and results are correlated with deformation of a compliant wall. ONR.
NASA Astrophysics Data System (ADS)
Sharma, R.; McCalley, J. D.
2016-12-01
Geomagnetic disturbance (GMD) causes the flow of geomagnetically induced currents (GIC) in the power transmission system that may cause large scale power outages and power system equipment damage. In order to plan for defense against GMD, it is necessary to accurately estimate the flow of GICs in the power transmission system. The current calculation as per NERC standards uses the 1-D earth conductivity models that don't reflect the coupling between the geoelectric and geomagnetic field components in the same direction. For accurate estimation of GICs, it is important to have spatially granular 3-D earth conductivity tensors, accurate DC network model of the transmission system and precisely estimated or measured input in the form of geomagnetic or geoelectric field data. Using these models and data the pre event, post event and online planning and assessment can be performed. The pre, post and online planning can be done by calculating GIC, analyzing voltage stability margin, identifying protection system vulnerabilities and estimating heating in transmission equipment. In order to perform the above mentioned tasks, an established GIC calculation and analysis procedure is needed that uses improved geophysical and DC network models obtained by model parameter tuning. The issue is addressed by performing the following tasks; 1) Geomagnetic field data and improved 3-D earth conductivity tensors are used to plot the geoelectric field map of a given area. The obtained geoelectric field map then serves as an input to the PSS/E platform, where through DC circuit analysis the GIC flows are calculated. 2) The computed GIC is evaluated against GIC measurements in order to fine tune the geophysical and DC network model parameters for any mismatch in the calculated and measured GIC. 3) The GIC calculation procedure is then adapted for a one in 100 year storm, in order to assess the impact of the worst case GMD on the power system. 4) Using the transformer models, the voltage
NASA Astrophysics Data System (ADS)
Koncek, O.; Krivonoska, J.
2014-11-01
The MCNP Monte Carlo code was used to simulate the collimating system of the 60Co therapy unit to calculate the primary and scattered photon fluences as well as the electron contamination incident to the isocentric plane as the functions of the irradiation field size. Furthermore, a Monte Carlo simulation for the polyenergetic Pencil Beam Kernels (PBKs) generation was performed using the calculated photon and electron spectra. The PBK was analytically fitted to speed up the dose calculation using the convolution technique in the homogeneous media. The quality of the PBK fit was verified by comparing the calculated and simulated 60Co broad beam profiles and depth dose curves in a homogeneous water medium. The inhomogeneity correction coefficients were derived from the PBK simulation of an inhomogeneous slab phantom consisting of various materials. The inhomogeneity calculation model is based on the changes in the PBK radial displacement and on the change of the forward and backward electron scattering. The inhomogeneity correction is derived from the electron density values gained from a complete 3D CT array and considers different electron densities through which the pencil beam is propagated as well as the electron density values located between the interaction point and the point of dose deposition. Important aspects and details of the algorithm implementation are also described in this study.
NASA Astrophysics Data System (ADS)
Wagner, J. E.; Arola, A.; Blumthaler, M.; Fitzka, M.; Kift, R.; Kreuter, A.; Rieder, H. E.; Simic, S.; Webb, A.; Weihs, P.
2009-04-01
Since the discovery of anthropogenic ozone depletion more than 30 year ago, the scientific community has shown an increasing interest in UV-B radiation. Nowadays, ground-based high quality measurements of spectrally resolved UV-radiation are available. On the other hand, 1-D- and 3-D models have been developed, that describe the radiative transfer through the atmosphere physically very accurately. Another approach for determining the UV-irradiance at the surface of the earth is the use of satellite-based reflectance measurements as input for retrieval algorithms. At the moment, the research focuses on the impact of clouds on UV-radiation, but the impact of mountains on UV-radiation, especially in combination with high surface albedo due to snowcover, is also very strong and detailed comparisons between measurements and modelling are lacking. Therefore, three measurement campaigns had been conducted in alpine areas of Austria (Innsbruck and Hoher Sonnblick). The goal was to investigate the impact of alpine terrain in combination with snowcover on spectral UV-irradiance and actinic flux. This contribution uses the ground-based UV-irradiance measurements to evaluate three different UV-irradiance calculation methods. Results from three different calculation methods (satellite retrieval, 1-D- and 3-D radiative transfer model) for UV radiation in terms of UV-Index, erythemally weighted daily doses and spectrally resolved UV-Irradiance at 305, 310, 324 and 380nm are presented and compared with ground-based high quality measurements. The real case study is performed in very inhomogenous terrain under clear sky conditions. The values of the different methods are not only compared for the measurements sites, but additionally the impact of altitude is investigated. So far it seems, that 1-D simulations show the best agreement (±10%) with the measurements whereas the 3-D model simulations and satellite retrieved values differ much more. Satellite retrieved values
A comparative study of dose distribution of PBT, 3D-CRT and IMRT for pediatric brain tumors.
Takizawa, Daichi; Mizumoto, Masashi; Yamamoto, Tetsuya; Oshiro, Yoshiko; Fukushima, Hiroko; Fukushima, Takashi; Terunuma, Toshiyuki; Okumura, Toshiyuki; Tsuboi, Koji; Sakurai, Hideyuki
2017-02-22
It was reported that proton beam therapy (PBT) reduced the normal brain dose compared with X-ray therapy for pediatric brain tumors. We considered whether there was not the condition that PBT was more disadvantageous than intensity modulated photon radiotherapy (IMRT) and 3D conventional radiotherapy (3D-CRT) for treatment of pediatric brain tumors about the dose reduction for the normal brain when the tumor location or tumor size were different. The subjects were 12 patients treated with PBT at our institute, including 6 cases of ependymoma treated by local irradiation and 6 cases of germinoma treated by irradiation of all four cerebral ventricles. IMRT and 3D-CRT treatment plans were made for these 12 cases, with optimization using the same planning conditions as those for PBT. Model cases were also compared using sphere targets with different diameters or locations in the brain, and the normal brain doses with PBT, IMRT and 3D-CRT were compared using the same planning conditions. PBT significantly reduced the average dose to normal brain tissue compared to 3D-CRT and IMRT in all cases. There was no difference between 3D-CRT and IMRT. The average normal brain doses for PBT, 3D-CRT, and IMRT were 5.1-34.8% (median 14.9%), 11.0-48.5% (23.8%), and 11.5-53.1% (23.5%), respectively, in ependymoma cases; and 42.3-61.2% (48.9%), 54.5-74.0% (62.8%), and 56.3-72.1% (61.2%), respectively, in germinoma cases. In the model cases, PBT significantly reduced the average normal brain dose for larger tumors and for tumors located at the periphery of the brain. PBT reduces the average dose to normal brain tissue, compared with 3D-CRT and IMRT. The effect is higher for a tumor that is larger or located laterally.
NASA Astrophysics Data System (ADS)
Hu, R.; Brauchler, R.; Hu, L.; Qiu, P.
2015-12-01
Currently, a major challenge in aquifer characterization is the determination of hydraulic parameters with high-spatial resolution. Since the mid-90's, various working groups have developed numerical evaluation approaches for hydraulic tomography: the inversion of hydraulic tests that have been recorded using tomographic arrangements. The practical application is often associated with long test times, complex evaluations, and prolonged computation times. In our study, a hydraulic tomographical data set consisted of 450 drawdown curves produced by a series of short term pumping tests conducted over 4 working days. Data was collected by two scientists without a technical staff. The tests were performed at the test site "Stegemühle", Göttingen, Germany in a confined sand and gravel aquifer with a thickness of 2-3 m. For the inversion, an approach has been used, which is based on the transformation of the groundwater flow equation into a form of Eikonal equation (Vasco et al., 2000). Utilizing this approach, the hydraulic data can be inverted using an Eikonal solver e.g. SIRT. This Eikonal solver is considerably computationally efficient and allows hundreds of draw down curves to be inverted on a standard laptop within minutes. Following the methodology described in Brauchler et al. 2013, 3D distribution of diffusivity and specific storage were directly reconstructed, and subsequently their product: the hydraulic conductivity. This study exemplifies that the required data can be recorded and analyzed efficiently in the field, which is a vital precondition for the in-situ field aquifer characterization with hydraulic tomography. Literature Vasco, D.W., Keers, H., Karasaki, K. (2000) Estimation of reservoir properties using transient pressure data: An asymptotic approach. Water Resour. Res. 36(12), 3447-3465 Brauchler, R., Hu, R., Hu, L., Jimenéz, S., Bayer, P., Ptak, T. (2013) Rapid field application of hydraulic tomography for resolving aquifer heterogeneity in
Massillon-Jl, G; Minniti, R; Mitch, M G; Maryanski, M J; Soares, C G
2009-03-21
Absorbed dose distributions in 3D imparted by a single (90)Sr/(90)Y beta particle seed source of the type used for intravascular brachytherapy were investigated. A polymer gel dosimetry medium was used as a dosemeter and phantom, while a special high-resolution laser CT scanner with a spatial resolution of 100 microm in all dimensions was used to quantify the data. We have measured the radial dose function, g(L)(r), observing that g(L)(r) increases to a maximum value and then decreases as the distance from the seed increases. This is in good agreement with previous data obtained with radiochromic film and thermoluminescent dosemeters (TLDs), even if the TLDs underestimate the dose at distances very close to the seed. Contrary to the measurements, g(L)(r) calculated through Monte Carlo simulations and reported previously steadily decreases without a local maximum as a function of the distance from the seed. At distances less than 1.5 mm, differences of more than 20% are observed between the measurements and the Monte Carlo calculations. This difference could be due to a possible underestimation of the energy absorbed into the seed core and encapsulation in the Monte Carlo simulation, as a consequence of the unknown precise chemical composition of the core and its respective density for this seed. The results suggest that g(L)(r) can be measured very close to the seed with a relative uncertainty of about 1% to 2%. The dose distribution is isotropic only at distances greater than or equal to 2 mm from the seed and is almost symmetric, independent of the depth. This study indicates that polymer gel coupled with the special small format laser CT scanner are valid and accurate methods for measuring the dose distribution at distances close to an intravascular brachytherapy seed.
Guo, Xiaoya; Zhu, Jian; Maehara, Akiko; Monoly, David; Samady, Habib; Wang, Liang; Billiar, Kristen L; Zheng, Jie; Yang, Chun; Mintz, Gary S; Giddens, Don P; Tang, Dalin
2017-02-01
Computational models have been used to calculate plaque stress and strain for plaque progression and rupture investigations. An intravascular ultrasound (IVUS)-based modeling approach is proposed to quantify in vivo vessel material properties for more accurate stress/strain calculations. In vivo Cine IVUS and VH-IVUS coronary plaque data were acquired from one patient with informed consent obtained. Cine IVUS data and 3D thin-slice models with axial stretch were used to determine patient-specific vessel material properties. Twenty full 3D fluid-structure interaction models with ex vivo and in vivo material properties and various axial and circumferential shrink combinations were constructed to investigate the material stiffness impact on stress/strain calculations. The approximate circumferential Young's modulus over stretch ratio interval [1.0, 1.1] for an ex vivo human plaque sample and two slices (S6 and S18) from our IVUS data were 1631, 641, and 346 kPa, respectively. Average lumen stress/strain values from models using ex vivo, S6 and S18 materials with 5 % axial shrink and proper circumferential shrink were 72.76, 81.37, 101.84 kPa and 0.0668, 0.1046, and 0.1489, respectively. The average cap strain values from S18 material models were 150-180 % higher than those from the ex vivo material models. The corresponding percentages for the average cap stress values were 50-75 %. Dropping axial and circumferential shrink consideration led to stress and strain over-estimations. In vivo vessel material properties may be considerably softer than those from ex vivo data. Material stiffness variations may cause 50-75 % stress and 150-180 % strain variations.
NASA Astrophysics Data System (ADS)
Guo, Zhenyan; Song, Yang; Yuan, Qun; Wulan, Tuya; Chen, Lei
2017-06-01
In this paper, a transient multi-parameter three-dimensional (3D) reconstruction method is proposed to diagnose and visualize a combustion flow field. Emission and transmission tomography based on spatial phase-shifted technology are combined to reconstruct, simultaneously, the various physical parameter distributions of a propane flame. Two cameras triggered by the internal trigger mode capture the projection information of the emission and moiré tomography, respectively. A two-step spatial phase-shifting method is applied to extract the phase distribution in the moiré fringes. By using the filtered back-projection algorithm, we reconstruct the 3D refractive-index distribution of the combustion flow field. Finally, the 3D temperature distribution of the flame is obtained from the refractive index distribution using the Gladstone-Dale equation. Meanwhile, the 3D intensity distribution is reconstructed based on the radiation projections from the emission tomography. Therefore, the structure and edge information of the propane flame are well visualized.
NASA Astrophysics Data System (ADS)
Montiel, F.; Squire, V. A.
2013-12-01
A new ocean wave/sea-ice interaction model is proposed that simulates how a directional wave spectrum evolves as it travels through a realistic marginal ice zone (MIZ), where wave/ice dynamics are entirely governed by coherent conservative wave scattering effects. Field experiments conducted by Wadhams et al. (1986) in the Greenland Sea generated important data on wave attenuation in the MIZ and, particularly, on whether the wave spectrum spreads directionally or collimates with distance from the ice edge. The data suggest that angular isotropy, arising from multiple scattering by ice floes, occurs close to the edge and thenceforth dominates wave propagation throughout the MIZ. Although several attempts have been made to replicate this finding theoretically, including by the use of numerical models, none have confronted this problem in a 3D MIZ with fully randomised floe distribution properties. We construct such a model by subdividing the discontinuous ice cover into adjacent infinite slabs of finite width parallel to the ice edge. Each slab contains an arbitrary (but finite) number of circular ice floes with randomly distributed properties. Ice floes are modeled as thin elastic plates with uniform thickness and finite draught. We consider a directional wave spectrum with harmonic time dependence incident on the MIZ from the open ocean, defined as a continuous superposition of plane waves traveling at different angles. The scattering problem within each slab is then solved using Graf's interaction theory for an arbitrary incident directional plane wave spectrum. Using an appropriate integral representation of the Hankel function of the first kind (see Cincotti et al., 1993), we map the outgoing circular wave field from each floe on the slab boundaries into a directional spectrum of plane waves, which characterizes the slab reflected and transmitted fields. Discretizing the angular spectrum, we can obtain a scattering matrix for each slab. Standard recursive
3D-HST + CANDELS: the Evolution of the Galaxy Size-mass Distribution Since Z=3
NASA Technical Reports Server (NTRS)
VanDerWel, A.; Franx, M.; vanDokkum, P. G.; Skelton, R. E.; Momcheva, I. G.; Whitaker, K. E.; Brammer, G. B.; Bell, E. F.; Rix, H.-W.; Wuyts, S.;
2014-01-01
Spectroscopic and photometric redshifts, stellar mass estimates, and rest-frame colors from the 3D-HST survey are combined with structural parameter measurements from CANDELS imaging to determine the galaxy size-mass distribution over the redshift (z) range 0 < z < 3. Separating early- and late-type galaxies on the basis of star-formation activity, we confirm that early-type galaxies are on average smaller than late-type galaxies at all redshifts, and find a significantly different rate of average size evolution at fixed galaxy mass, with fast evolution for the early-type population, effective radius is in proportion to (1 + z) (sup -1.48), and moderate evolution for the late-type population, effective radius is in proportion to (1 + z) (sup -0.75). The large sample size and dynamic range in both galaxy mass and redshift, in combination with the high fidelity of our measurements due to the extensive use of spectroscopic data, not only fortify previous results, but also enable us to probe beyond simple average galaxy size measurements. At all redshifts the slope of the size-mass relation is shallow, effective radius in proportion to mass of a black hole (sup 0.22), for late-type galaxies with stellar mass > 3 x 10 (sup 9) solar masses, and steep, effective radius in proportion to mass of a black hole (sup 0.75), for early-type galaxies with stellar mass > 2 x 10 (sup 10) solar masses. The intrinsic scatter is approximately or less than 0.2 decimal exponents for all galaxy types and redshifts. For late-type galaxies, the logarithmic size distribution is not symmetric, but skewed toward small sizes: at all redshifts and masses a tail of small late-type galaxies exists that overlaps in size with the early-type galaxy population. The number density of massive (approximately 10 (sup 11) solar masses), compact (effective radius less than 2 kiloparsecs) early-type galaxies increases from z = 3 to z = 1.5 - 2 and then strongly decreases at later cosmic times.
Temperature dependences of self- and N2-broadened line-shape parameters in the ν3 and ν5 bands of 12CH3D: Measurements and calculations
NASA Astrophysics Data System (ADS)
Predoi-Cross, A.; Malathy Devi, V.; Sutradhar, P.; Sinyakova, T.; Buldyreva, J.; Sung, K.; Smith, M. A. H.; Mantz, A. W.
2016-07-01
This paper presents the results of a spectroscopic line shape study of self- and nitrogen-broadened 12CH3D transitions in the ν3 and ν5 bands in the Triad region. We combined five pure gas spectra with eighteen spectra of lean mixtures of 12CH3D and nitrogen, all recorded with a Bruker IFS-125 HR Fourier transform spectrometer. The spectra have been analyzed simultaneously using a multispectrum nonlinear least squares fitting technique. N2-broadened line parameters for 184 transitions in the ν3 band and 205 transitions in the ν5 band were measured. In addition, line positions and line intensities were measured for 168 transitions in the ν3 band and 214 transitions in the ν5 band. We have observed 10 instances of weak line mixing corresponding to K″=3 A1 or A2 transitions. Comparisons were made for the N2-broadening coefficients and associated temperature exponents with corresponding values calculated using a semi-classical Robert Bonamy type formalism that involved an inter-molecular potential with terms corresponding to short- and long-range interactions, and exact classical molecular trajectories. The theoretical N2-broadened coefficients are overestimated for high J values, but are in good agreement with the experimental values for small and middle range J values.
Hoffman, E.L.; Ammerman, D.J.
1995-04-01
A series of tests investigating dynamic pulse buckling of a cylindrical shell under axial impact is compared to several 2D and 3D finite element simulations of the event. The purpose of the work is to investigate the performance of various analysis codes and element types on a problem which is applicable to radioactive material transport packages, and ultimately to develop a benchmark problem to qualify finite element analysis codes for the transport package design industry. During the pulse buckling tests, a buckle formed at each end of the cylinder, and one of the two buckles became unstable and collapsed. Numerical simulations of the test were performed using PRONTO, a Sandia developed transient dynamics analysis code, and ABAQUS/Explicit with both shell and continuum elements. The calculations are compared to the tests with respect to deformed shape and impact load history.
NASA Astrophysics Data System (ADS)
Serafimovski, T.; Volkov, A. V.; Serafimovski, D.; Tasev, G.; Ivanovski, I.; Murashov, K. Yu.
2017-07-01
The Plavica Au-Ag-Cu deposit is related to the large Neogene volcanic center, which complicates the paleocaldera in the central Kratovo-Zletovo ore district of eastern Macedonia. Based on the geology, ore mineralogy, wall-rock alteration, and fluid inclusions, the Plavica deposit has been referred to the epithermal high-sulfidation type. The general 3D model of orebody at this deposit is based on its general geological structure and complex distribution of metal contents. The framework of the 3D model, which has been constructed in the ArcGIS System, comprises 195 exploration boreholes 47295.8 m in total length. The 3D model allows to a better understanding of distribution of mineralization and supplements the geological data on the deposit.
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.
Cheng, Lan; Gauss, Jürgen; Ruscic, Branko; ...
2017-01-12
Benchmark scalar-relativistic coupled-cluster calculations for dissociation energies of the 20 diatomic molecules containing 3d transition metals in the 3dMLBE20 database ( J. Chem. Theory Comput. 2015, 11, 2036) are reported in this paper. Electron correlation and basis set effects are systematically studied. The agreement between theory and experiment is in general satisfactory. For a subset of 16 molecules, the standard deviation between computational and experimental values is 9 kJ/mol with the maximum deviation being 15 kJ/mol. The discrepancies between theory and experiment remain substantial (more than 20 kJ/mol) for VH, CrH, CoH, and FeH. To explore the source of themore » latter discrepancies, the analysis used to determine the experimental dissociation energies for VH and CrH is revisited. It is shown that, if improved values are used for the heterolytic C–H dissociation energies of di- and trimethylamine involved in the experimental determination, the experimental values for the dissociation energies of VH and CrH are increased by 18 kJ/mol, such that D0(VH) = 223 ± 7 kJ/mol and D0(CrH) = 204 ± 7 kJ/mol (or De(VH) = 233 ± 7 kJ/mol and De(CrH) = 214 ± 7 kJ/mol). Finally, the new experimental values agree quite well with the calculated values, showing the consistency of the computation and the measured reaction thresholds.« less
Zhang, Y; Yang, J; Liu, H; Liu, D
2014-06-01
Purpose: The purpose of this work is to compare the verification results of three solutions (2D/3D ionization chamber arrays measurement and Monte Carlo simulation), the results will help make a clinical decision as how to do our cervical IMRT verification. Methods: Seven cervical cases were planned with Pinnacle 8.0m to meet the clinical acceptance criteria. The plans were recalculated in the Matrixx and Delta4 phantom with the accurate plans parameters. The plans were also recalculated by Monte Carlo using leaf sequences and MUs for individual plans of every patient, Matrixx and Delta4 phantom. All plans of Matrixx and Delta4 phantom were delivered and measured. The dose distribution of iso slice, dose profiles, gamma maps of every beam were used to evaluate the agreement. Dose-volume histograms were also compared. Results: The dose distribution of iso slice and dose profiles from Pinnacle calculation were in agreement with the Monte Carlo simulation, Matrixx and Delta4 measurement. A 95.2%/91.3% gamma pass ratio was obtained between the Matrixx/Delta4 measurement and Pinnacle distributions within 3mm/3% gamma criteria. A 96.4%/95.6% gamma pass ratio was obtained between the Matrixx/Delta4 measurement and Monte Carlo simulation within 2mm/2% gamma criteria, almost 100% gamma pass ratio within 3mm/3% gamma criteria. The DVH plot have slightly differences between Pinnacle and Delta4 measurement as well as Pinnacle and Monte Carlo simulation, but have excellent agreement between Delta4 measurement and Monte Carlo simulation. Conclusion: It was shown that Matrixx/Delta4 and Monte Carlo simulation can be used very efficiently to verify cervical IMRT delivery. In terms of Gamma value the pass ratio of Matrixx was little higher, however, Delta4 showed more problem fields. The primary advantage of Delta4 is the fact it can measure true 3D dosimetry while Monte Carlo can simulate in patients CT images but not in phantom.
NASA Astrophysics Data System (ADS)
Whitmarsh, Tristan; Humbert, Ludovic; De Craene, Mathieu; del Río Barquero, Luis M.; Fritscher, Karl; Schubert, Rainer; Eckstein, Felix; Link, Thomas; Frangi, Alejandro F.
2010-03-01
Area Bone Mineral Density (aBMD) measured by Dual-energy X-ray Absorptiometry (DXA) is an established criterion in the evaluation of hip fracture risk. The evaluation from these planar images, however, is limited to 2D while it has been shown that proper 3D assessment of both the shape and the Bone Mineral Density (BMD) distribution improves the fracture risk estimation. In this work we present a method to reconstruct both the 3D bone shape and 3D BMD distribution of the proximal femur from a single DXA image. A statistical model of shape and a separate statistical model of the BMD distribution were automatically constructed from a set of Quantitative Computed Tomography (QCT) scans. The reconstruction method incorporates a fully automatic intensity based 3D-2D registration process, maximizing the similarity between the DXA and a digitally reconstructed radiograph of the combined model. For the construction of the models, an in vitro dataset of QCT scans of 60 anatomical specimens was used. To evaluate the reconstruction accuracy, experiments were performed on simulated DXA images from the QCT scans of 30 anatomical specimens. Comparisons between the reconstructions and the same subject QCT scans showed a mean shape accuracy of 1.2mm, and a mean density error of 81mg/cm3. The results show that this method is capable of accurately reconstructing both the 3D shape and 3D BMD distribution of the proximal femur from DXA images used in clinical routine, potentially improving the diagnosis of osteoporosis and fracture risk assessments at a low radiation dose and low cost.
Poder, Joel; Corde, Stéphanie
2013-12-15
Purpose: The purpose of this study was to measure the dose distributions for different Radiation Oncology Physics and Engineering Services, Australia (ROPES) type eye plaques loaded with I-125 (model 6711) seeds using GafChromic{sup ®} EBT3 films, in order to verify the dose distributions in the Plaque Simulator™ (PS) ophthalmic 3D treatment planning system. The brachytherapy module of RADCALC{sup ®} was used to independently check the dose distributions calculated by PS. Correction factors were derived from the measured data to be used in PS to account for the effect of the stainless steel ROPES plaque backing on the 3D dose distribution.Methods: Using GafChromic{sup ®} EBT3 films inserted in a specially designed Solid Water™ eye ball phantom, dose distributions were measured three-dimensionally both along and perpendicular to I-125 (model 6711) loaded ROPES eye plaque's central axis (CAX) with 2 mm depth increments. Each measurement was performed in full scatter conditions both with and without the stainless steel plaque backing attached to the eye plaque, to assess its effect on the dose distributions. Results were compared to the dose distributions calculated by Plaque Simulator™ and checked independently with RADCALC{sup ®}.Results: The EBT3 film measurements without the stainless steel backing were found to agree with PS and RADCALC{sup ®} to within 2% and 4%, respectively, on the plaque CAX. Also, RADCALC{sup ®} was found to agree with PS to within 2%. The CAX depth doses measured using EBT3 film with the stainless steel backing were observed to result in a 4% decrease relative to when the backing was not present. Within experimental uncertainty, the 4% decrease was found to be constant with depth and independent of plaque size. Using a constant dose correction factor of T= 0.96 in PS, where the calculated dose for the full water scattering medium is reduced by 4% in every voxel in the dose grid, the effect of the plaque backing was accurately
Poder, Joel; Corde, Stéphanie
2013-12-01
The purpose of this study was to measure the dose distributions for different Radiation Oncology Physics and Engineering Services, Australia (ROPES) type eye plaques loaded with I-125 (model 6711) seeds using GafChromic(®) EBT3 films, in order to verify the dose distributions in the Plaque Simulator™ (PS) ophthalmic 3D treatment planning system. The brachytherapy module of RADCALC(®) was used to independently check the dose distributions calculated by PS. Correction factors were derived from the measured data to be used in PS to account for the effect of the stainless steel ROPES plaque backing on the 3D dose distribution. Using GafChromic(®) EBT3 films inserted in a specially designed Solid Water™ eye ball phantom, dose distributions were measured three-dimensionally both along and perpendicular to I-125 (model 6711) loaded ROPES eye plaque's central axis (CAX) with 2 mm depth increments. Each measurement was performed in full scatter conditions both with and without the stainless steel plaque backing attached to the eye plaque, to assess its effect on the dose distributions. Results were compared to the dose distributions calculated by Plaque Simulator™ and checked independently with RADCALC(®). The EBT3 film measurements without the stainless steel backing were found to agree with PS and RADCALC(®) to within 2% and 4%, respectively, on the plaque CAX. Also, RADCALC(®) was found to agree with PS to within 2%. The CAX depth doses measured using EBT3 film with the stainless steel backing were observed to result in a 4% decrease relative to when the backing was not present. Within experimental uncertainty, the 4% decrease was found to be constant with depth and independent of plaque size. Using a constant dose correction factor of T = 0.96 in PS, where the calculated dose for the full water scattering medium is reduced by 4% in every voxel in the dose grid, the effect of the plaque backing was accurately modeled in the planning system. Off-axis profiles
Li, Jianyi; Nie, Lanying; Li, Zeyu; Lin, Lijun; Tang, Lei; Ouyang, Jun
2012-01-01
Anatomical corrosion casts of human specimens are useful teaching aids. However, their use is limited due to ethical dilemmas associated with their production, their lack of perfect reproducibility, and their consumption of original specimens in the process of casting. In this study, new approaches with modern distribution of complex anatomical spatial information were explored to overcome these limitations through the digitalization of anatomical casts of human specimens through three-dimensional (3D) reconstruction, rapid prototype production, and Web-based 3D atlas construction. The corrosion cast of a lung, along with its associated arteries, veins, trachea, and bronchial tree was CT-scanned, and the data was then processed by Mimics software. Data from the lung casts were then reconstructed into 3D models using a hybrid method, utilizing both "image threshold" and "region growing." The fine structures of the bronchial tree, arterial, and venous network of the lung were clearly displayed and demonstrated their distinct relationships. The multiple divisions of bronchi and bronchopulmonary segments were identified. The 3D models were then uploaded into a rapid prototype 3D printer to physically duplicate the cast. The physically duplicated model of the lung was rescanned by CT and reconstructed to detect its production accuracy. Gross observation and accuracy detection were used to evaluate the duplication and few differences were found. Finally, Virtual Reality Modeling Language (VRML) was used to edit the 3D casting models to construct a Web-based 3D atlas accessible through Internet Explorer with 3D display and annotation functions. Copyright © 2012 American Association of Anatomists.
Tsvetkov, Pavel; Dickerson, Bryan; French, Joseph; McEachern, Donald; Ougouag, Abderrafi
2014-04-30
Robust sensing technologies allowing for 3D in-core performance monitoring in real time are of paramount importance for already established LWRs to enhance their reliability and availability per year, and therefore, to further facilitate their economic competitiveness via predictive assessment of the in-core conditions.
ERIC Educational Resources Information Center
Nazari, Mohammad Ali; Perrier, Pascal; Payan, Yohan
2013-01-01
Purpose: The authors aimed to design a distributed lambda model (DLM), which is well adapted to implement three-dimensional (3-D), finite-element descriptions of muscles. Method: A muscle element model was designed. Its stress-strain relationships included the active force-length characteristics of the ? model along the muscle fibers, together…
Pogosyan, Dmitry; Gay, Christophe; Pichon, Christophe
2009-10-15
The full moments expansion of the joint probability distribution of an isotropic random field, its gradient, and invariants of the Hessian are presented in 2 and 3D. It allows for explicit expression for the Euler characteristic in ND and computation of extrema counts as functions of the excursion set threshold and the spectral parameter, as illustrated on model examples.
ERIC Educational Resources Information Center
Nazari, Mohammad Ali; Perrier, Pascal; Payan, Yohan
2013-01-01
Purpose: The authors aimed to design a distributed lambda model (DLM), which is well adapted to implement three-dimensional (3-D), finite-element descriptions of muscles. Method: A muscle element model was designed. Its stress-strain relationships included the active force-length characteristics of the ? model along the muscle fibers, together…
Effects of energy spectrum on dose distribution calculations for high energy electron beams.
Toutaoui, Abdelkader; Khelassi-Toutaoui, Nadia; Brahimi, Zakia; Chami, Ahmed Chafik
2009-01-01
In an early work we have demonstrated the possibility of using Monte Carlo generated pencil beams for 3D electron beam dose calculations. However, in this model the electron beam was considered as monoenergetic and the effects of the energy spectrum were taken into account by correction factors, derived from measuring central-axis depth dose curves. In the present model, the electron beam is considered as polyenergetic and the pencil beam distribution of a clinical electron beam, of a given nominal energy, is represented as a linear combination of Monte Carlo monoenergetic pencil beams. The coefficients of the linear combination describe the energy spectrum of the clinical electron beam, and are chosen to provide the best-fit between the calculated and measured central axis depth dose, in water. The energy spectrum is determined by the constrained least square method. The angular distribution of the clinical electron beam is determined by in-air penumbra measurements. The predictions of this algorithm agree very well with the measurements in the region near the surface, and the discrepancies between the measured and calculated dose distributions, behind 3D heterogeneities, are reduced to less than 10%. We have demonstrated a new algorithm for 3D electron beam dose calculations, which takes into account the energy spectra. Results indicate that the use of this algorithm leads to a better modeling of dose distributions downstream, from complex heterogeneities.
Effects of energy spectrum on dose distribution calculations for high energy electron beams
Toutaoui, Abdelkader; Khelassi-Toutaoui, Nadia; Brahimi, Zakia; Chami, Ahmed Chafik
2009-01-01
In an early work we have demonstrated the possibility of using Monte Carlo generated pencil beams for 3D electron beam dose calculations. However, in this model the electron beam was considered as monoenergetic and the effects of the energy spectrum were taken into account by correction factors, derived from measuring central-axis depth dose curves. In the present model, the electron beam is considered as polyenergetic and the pencil beam distribution of a clinical electron beam, of a given nominal energy, is represented as a linear combination of Monte Carlo monoenergetic pencil beams. The coefficients of the linear combination describe the energy spectrum of the clinical electron beam, and are chosen to provide the best-fit between the calculated and measured central axis depth dose, in water. The energy spectrum is determined by the constrained least square method. The angular distribution of the clinical electron beam is determined by in-air penumbra measurements. The predictions of this algorithm agree very well with the measurements in the region near the surface, and the discrepancies between the measured and calculated dose distributions, behind 3D heterogeneities, are reduced to less than 10%. We have demonstrated a new algorithm for 3D electron beam dose calculations, which takes into account the energy spectra. Results indicate that the use of this algorithm leads to a better modeling of dose distributions downstream, from complex heterogeneities. PMID:20126560
NASA Astrophysics Data System (ADS)
Han, J. H.; Wang, Y.; Cai, H.; An, G. F.; Rong, K. P.; Yu, H.; Wang, S. Y.; Wang, H. Y.; Zhang, W.; Xue, L. P.; Zhou, J.
2017-06-01
We develop a new 3D-model to evaluate the light characteristics and the thermal features of a cesium-vapor laser end-pumped by a laser diode. The theoretical model is based on the principles of both heat transfer and laser kinetics. The 3-dimensional population density distribution and temperature distribution are both systematically obtained and analyzed. The methodology is thought to be useful for realization of a high-powered diode-pumped alkali laser (DPAL) in the future.
NASA Technical Reports Server (NTRS)
Predoi-Cross, A.; Hambrook, Kyle; Brawley-Tremblay, Marco; Bouanich, J. P.; Smith, Mary Ann H.
2006-01-01
In this paper, we report measured Lorentz N2-broadening and N2-induced pressure-shift coefficients of CH3D in the v2 fundamental band using a multispectrum fitting technique. These measurements were made by analyzing 11 laboratory absorption spectra recorded at 0.0056 cm(exp -1) resolution using the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak, Arizona. The spectra were obtained using two absorption cells with path lengths of 10.2 and 25 cm. The total sample pressures ranged from 0.98 to 402.25 Torr with CH3D volume mixing ratios of 0.01 in nitrogen. We have been able to determine the N2 pressure- broadening coefficients of 368 v2 transitions with quantum numbers as high as J"= 20 and K = 16, where K" = K' equivalent to K (for a parallel band). The measured N2-broadening coefficients range from 0.0248 to 0.0742 cm(exp -1) atm(exp -1) at 296 K. All the measured pressure-shifts are negative. The reported N2-induced pressure-shift coefficients vary from about 0.0003 to 0.0094 cm(exp -1) atm(exp -1). We have examined the dependence of the measured broadening and shift parameters on the J", and K quantum numbers and also developed empirical expressions to describe the broadening coefficients in terms of m (m = -J", J", and J" + 1 in the (sup Q)P-, (sup Q)Q-, and (sup Q)R-branch, respectively) and K. On average, the empirical expressions reproduce the measured broadening coefficients to within 4.7%. The N2-broadening and pressureshift coefficients were calculated on the basis of a semiclassical model of interacting linear molecules performed by considering in addition to the electrostatic contributions the atom atom Lennard-Jones potential. The theoretical results of the broadening coefficients are in good overall agreement with the experimental data (8.7%). The N2-pressure shifts whose vibrational contribution is derived from parameters fitted in the (sup Q)Q-branch of self-induced shifts of CH3D, are also in
Yepes, Diana; Seidel, Robert; Winter, Bernd; Blumberger, Jochen; Jaque, Pablo
2014-06-19
Photoelectron spectroscopy measurements and density functional calculations are combined to determine the lowest electron binding energies of first-row transition-metal aqua ions, titanium through copper, with 3d(1) through 3d(9) electronic configurations, in their most common oxidation states. Vertical ionization energies are found to oscillate considerably between 6.76 and 9.65 eV for the dications and between 7.05 and 10.28 eV for the respective trivalent cations. The metal cations are modeled as [M(H2O)n](q+) clusters (q = 2, 3, and 4; n = 6 and 18) surrounded by continuum solvent. The performance of 10 exchange-correlation functionals, two GGAs, three MGGAs, two HGGAs and three HMGGAs, combined with the MDF10(ECP)/6-31+G(d,p) basis set is assessed for 11 M-O bond distances, 10 vertical ionization energies, 6 adiabatic ionization energies, and the associated reorganization free energies. We find that for divalent cations the HGGA and HMGGA functionals in combination with the 18 water model show the best agreement with experimental vertical ionization energies and geometries; for trivalent ions, the MGGA functionals perform best. The corresponding reorganization free energies (λo) of the oxidized ions are significantly underestimated with all DFT functionals and cluster models. This indicates that the structural reorganization of the solvation shell upon ionization is not adequately accounted for by the simple solvation models used, emphasizing the importance of extended sampling of thermally accessible solvation structures for an accurate computation of this quantity. The photoelectron spectroscopy measurements reported herein provide a comprehensive set of transition-metal redox energetic quantities for future electronic structure benchmarks.
Tang, Qinggong; Piard, Charlotte; Lin, Jonathan; Nan, Kai; Guo, Ting; Caccamese, John; Fisher, John; Chen, Yu
2017-09-16
Regenerative medicine has emerged as an important discipline that aims to repair injury or replace damaged tissues or organs by introducing living cells or functioning tissues. Successful regenerative medicine strategies will likely depend upon a simultaneous optimization strategy for the design of biomaterials, cell-seeding methods, cell-biomaterial interactions and molecular signaling within the engineered tissues. It remains a challenge to image three-dimensional (3-D) structures and functions of the cell-seeded scaffold in mesoscopic scale (>2∼3 mm). In this study, we utilized angled fluorescence laminar optical tomography (aFLOT), which allows depth-resolved molecular characterization of engineered tissues in 3-D to investigate cell viability, migration and bone mineralization within bone tissue engineering scaffolds in situ. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
NASA Astrophysics Data System (ADS)
Maufroy, E.; Gaffet, S.; Operto, S.; Cruz-Atienza, V. M.; Senechal, G.; Dietrich, M.; Zeyen, H.; Sardou, O.; Boyer, D.
2008-12-01
The understanding of seismic wave interaction with both topography and geological structures is one of a principal focus of seismic risk characterization. Seasonal or artificial variations of water (or more generally fluid or gas) saturation in the medium revealed by local variations of rheological parameters (VP, VS, QP, QS, and density) may strongly impact the seismic and the hydro-mechanical site response. The problem addressed here is the characterization of these potential site effects, which are of great interest in the context of underground storage and effects of anthropogenic structures. With the foregoing in mind, a seismic experiment was carried out in 2006 at the LSBB Underground Laboratory (http://lsbb.unice.fr), Rustrel, France. A total of 189 seismometers (3D 0.1 Hz Agecodagis) were spread on the surface of the massif with a slope of 30%, 150 vertical geophones (14 Hz) distributed along the roof of the 800 m long tunnel at LSBB. A two-dimensional profile of 100 shots (150 g equiv. TNT) were used for imaging the rheological properties of the subterranean karstic medium. A 3D P-velocity model was obtained from the reflection and surface to depth transmission P-wave travel times featuring the foregoing 2D tomographic profile. Main faults and P-wave velocities correlate well with the two main lithological formations (Barremian and Bedoulian limestones) [S.S.B.S. program, 1965]. As a preliminary step, finite difference modelling [Shake3D, Cruz-Atienza et al., 2007] using fixed VP/VS ratio provided a means for topographic site effect assessment. With these parameters, deduced mean amplification factors reach values from 3 to 6. There are shadow regions with low ground motion. There are also seismic lenses where seismic energy focusing occurs. These depend on the topography shape and relative source location. In a more realistic medium deduced from full waveform inversion [Operto et al., 2004], variations of VP/VS ratio and quality factors QP, QS, are
Gulyás, Attila I.; Freund, Tamás F.; Káli, Szabolcs
2016-01-01
In vivo and in vitro multichannel field and somatic intracellular recordings are frequently used to study mechanisms of network pattern generation. When interpreting these data, neurons are often implicitly considered as electrotonically compact cylinders with a homogeneous distribution of excitatory and inhibitory inputs. However, the actual distributions of dendritic length, diameter, and the densities of excitatory and inhibitory input are non-uniform and cell type-specific. We first review quantitative data on the dendritic structure and synaptic input and output distribution of pyramidal cells (PCs) and interneurons in the hippocampal CA1 area. Second, using multicompartmental passive models of four different types of neurons, we quantitatively explore the effect of differences in dendritic structure and synaptic distribution on the errors and biases of voltage clamp measurements of inhibitory and excitatory postsynaptic currents. Finally, using the 3-dimensional distribution of dendrites and synaptic inputs we calculate how different inhibitory and excitatory inputs contribute to the generation of local field potential in the hippocampus. We analyze these effects at different realistic background activity levels as synaptic bombardment influences neuronal conductance and thus the propagation of signals in the dendritic tree. We conclude that, since dendrites are electrotonically long and entangled in 3D, somatic intracellular and field potential recordings miss the majority of dendritic events in some cell types, and thus overemphasize the importance of perisomatic inhibitory inputs and belittle the importance of complex dendritic processing. Modeling results also suggest that PCs and inhibitory neurons probably use different input integration strategies. In PCs, second- and higher-order thin dendrites are relatively well-isolated from each other, which may support branch-specific local processing as suggested by studies of active dendritic integration. In
Gulyás, Attila I; Freund, Tamás F; Káli, Szabolcs
2016-01-01
In vivo and in vitro multichannel field and somatic intracellular recordings are frequently used to study mechanisms of network pattern generation. When interpreting these data, neurons are often implicitly considered as electrotonically compact cylinders with a homogeneous distribution of excitatory and inhibitory inputs. However, the actual distributions of dendritic length, diameter, and the densities of excitatory and inhibitory input are non-uniform and cell type-specific. We first review quantitative data on the dendritic structure and synaptic input and output distribution of pyramidal cells (PCs) and interneurons in the hippocampal CA1 area. Second, using multicompartmental passive models of four different types of neurons, we quantitatively explore the effect of differences in dendritic structure and synaptic distribution on the errors and biases of voltage clamp measurements of inhibitory and excitatory postsynaptic currents. Finally, using the 3-dimensional distribution of dendrites and synaptic inputs we calculate how different inhibitory and excitatory inputs contribute to the generation of local field potential in the hippocampus. We analyze these effects at different realistic background activity levels as synapt