WorldWideScience

Sample records for 3-d thermal evaluations

  1. Evaluation of Methods for Coregistration and Fusion of Rpas-Based 3d Point Clouds and Thermal Infrared Images

    Hoegner, L.; Tuttas, S.; Xu, Y.; Eder, K.; Stilla, U.

    2016-06-01

    This paper discusses the automatic coregistration and fusion of 3d point clouds generated from aerial image sequences and corresponding thermal infrared (TIR) images. Both RGB and TIR images have been taken from a RPAS platform with a predefined flight path where every RGB image has a corresponding TIR image taken from the same position and with the same orientation with respect to the accuracy of the RPAS system and the inertial measurement unit. To remove remaining differences in the exterior orientation, different strategies for coregistering RGB and TIR images are discussed: (i) coregistration based on 2D line segments for every single TIR image and the corresponding RGB image. This method implies a mainly planar scene to avoid mismatches; (ii) coregistration of both the dense 3D point clouds from RGB images and from TIR images by coregistering 2D image projections of both point clouds; (iii) coregistration based on 2D line segments in every single TIR image and 3D line segments extracted from intersections of planes fitted in the segmented dense 3D point cloud; (iv) coregistration of both the dense 3D point clouds from RGB images and from TIR images using both ICP and an adapted version based on corresponding segmented planes; (v) coregistration of both image sets based on point features. The quality is measured by comparing the differences of the back projection of homologous points in both corrected RGB and TIR images.

  2. 3D Multifunctional Ablative Thermal Protection System

    Feldman, Jay; Venkatapathy, Ethiraj; Wilkinson, Curt; Mercer, Ken

    2015-01-01

    NASA is developing the Orion spacecraft to carry astronauts farther into the solar system than ever before, with human exploration of Mars as its ultimate goal. One of the technologies required to enable this advanced, Apollo-shaped capsule is a 3-dimensional quartz fiber composite for the vehicle's compression pad. During its mission, the compression pad serves first as a structural component and later as an ablative heat shield, partially consumed on Earth re-entry. This presentation will summarize the development of a new 3D quartz cyanate ester composite material, 3-Dimensional Multifunctional Ablative Thermal Protection System (3D-MAT), designed to meet the mission requirements for the Orion compression pad. Manufacturing development, aerothermal (arc-jet) testing, structural performance, and the overall status of material development for the 2018 EM-1 flight test will be discussed.

  3. Dynamics of 3D isolated thermal filaments

    Walkden, N R; Militello, F; Omotani, J T

    2016-01-01

    Simulations have been carried out to establish how electron thermal physics, introduced in the form of a dynamic electron temperature, affects isolated filament motion and dynamics in 3D. It is found that thermal effects impact filament motion in two major ways when the filament has a significant temperature perturbation compared to its density perturbation: They lead to a strong increase in filament propagation in the bi-normal direction and a significant decrease in net radial propagation. Both effects arise from the temperature dependence of the sheath current which leads to a non-uniform floating potential, with the latter effect supplemented by faster pressure loss. The reduction in radial velocity can only occur when the filament cross-section loses angular symmetry. The behaviour is observed across different filament sizes and suggests that filaments with much larger temperature perturbations than density perturbations are more strongly confined to the near SOL region.

  4. 3D SURFACE GENERATION FROM AERIAL THERMAL IMAGERY

    B. Khodaei

    2015-12-01

    Full Text Available Aerial thermal imagery has been recently applied to quantitative analysis of several scenes. For the mapping purpose based on aerial thermal imagery, high accuracy photogrammetric process is necessary. However, due to low geometric resolution and low contrast of thermal imaging sensors, there are some challenges in precise 3D measurement of objects. In this paper the potential of thermal video in 3D surface generation is evaluated. In the pre-processing step, thermal camera is geometrically calibrated using a calibration grid based on emissivity differences between the background and the targets. Then, Digital Surface Model (DSM generation from thermal video imagery is performed in four steps. Initially, frames are extracted from video, then tie points are generated by Scale-Invariant Feature Transform (SIFT algorithm. Bundle adjustment is then applied and the camera position and orientation parameters are determined. Finally, multi-resolution dense image matching algorithm is used to create 3D point cloud of the scene. Potential of the proposed method is evaluated based on thermal imaging cover an industrial area. The thermal camera has 640×480 Uncooled Focal Plane Array (UFPA sensor, equipped with a 25 mm lens which mounted in the Unmanned Aerial Vehicle (UAV. The obtained results show the comparable accuracy of 3D model generated based on thermal images with respect to DSM generated from visible images, however thermal based DSM is somehow smoother with lower level of texture. Comparing the generated DSM with the 9 measured GCPs in the area shows the Root Mean Square Error (RMSE value is smaller than 5 decimetres in both X and Y directions and 1.6 meters for the Z direction.

  5. Thermal 3D Modeling of Geothermal Area Using Terrestrial Photogrammetry

    Akcay, Ozgun; Cuneyt Erenoglu, Ramazan; Erenoglu, Oya; Yılmazturk, Ferruh; Karaca, Zeki

    2015-04-01

    Photogrammetry and computer vision, sciences producing high accuracy 3D models from digital images based on projective geometry. 3D models can also be produced using thermal camera images using photogrammetry and computer vision techniques. Thermal images are capable of displaying hotspots on geothermal areas as a heat source in details. In the research, Tuzla geothermal area in Çanakkale province of Turkey is inspected using imaging techniques of terrestrial photogrammetry. Both a digital camera Canon EOS 650D and an infrared camera Optris PI 450 are used to obtain images of the thermal site. Calibration parameters (focal length, principle point, distortion coefficients) of thermal and digital cameras are determined using the calibration test field at the laboratory before the field work. In order to provide the georeferencing and the robustness of the 3D model, aluminum discs having diameter of 30 centimeters as ground control points (GCPs) are set to the geothermal area appropriately before imaging. Aluminum targets are chosen as the GCP because they are determined on the image depending on the contrast reflectance rate of the aluminum. Using GNSS RTK receivers supplying ±1 cm accuracy positioning, GCPs are measured so as to implement photogrammetric process successfully with thermal images. Numerous corresponding points are detected on the overlapped images with image matching techniques. Later on, bundle block adjustment is applied to calculate the revised interior orientation parameters of camera and exterior orientation parameters of camera positions. The 3D model showing details of the surface temperatures of the geothermal area are produced with multi view stereo (MVS) technique. The technique is able to produce 3D representation (point cloud, mesh and textured surface) of the field from both the thermal and digital images. The research presents that photogrammetric evaluation of thermal images is a noteworthy method to obtain a quick- accurate 3D

  6. Evaluation of the thermal and hydraulic performances of a very thin sintered copper flat heat pipe for 3D microsystem packages

    Tzanova, S; Avenas, Y; Schaeffer, Ch

    2008-01-01

    The reported research work presents numerical studies validated by experimental results of a flat micro heat pipe with sintered copper wick structure. The objectives of this project are to produce and demonstrate the efficiency of the passive cooling technology (heat pipe) integrated in a very thin electronic substrate that is a part of a multifunctional 3-D electronic package. The enhanced technology is dedicated to the thermal management of high dissipative microsystems having heat densities of more than 10W/cm2. Future applications are envisaged in the avionics sector. In this research 2D numerical hydraulic model has been developed to investigate the performance of a very thin flat micro heat pipe with sintered copper wick structure, using water as a refrigerant. Finite difference method has been used to develop the model. The model has been used to determine the mass transfer and fluid flow in order to evaluate the limits of heat transport capacity as functions of the dimensions of the wick and the vapou...

  7. Thermal Protection System Materials (TPSM): 3D MAT Project

    National Aeronautics and Space Administration — The 3D MAT Project seeks to design and develop a game changing Woven Thermal Protection System (TPS) technology tailored to meet the needs of the Orion...

  8. Basis for Coupled 3-D Neutronics-Thermal-Hydraulics

    Aragonés Beltrán, José María

    2008-01-01

    The purpose of this seminar is first to discuss the basis of the coupling between 3-D Neutron- Kinetics and Thermal-Hydraulics codes, including the control and 3-D variables to interchange, the transform of the 3-D NK and TH core nodalizations, and the schemes for temporal coupling and time-step control. As representative examples of the NK-TH core coupling, we discuss first the integration of a 3-D NK nodal code with a TH subchannel code, for detailed transient core analysis; and second the ...

  9. Reduction of thermal conductivity by nanoscale 3D phononic crystal.

    Yang, Lina; Yang, Nuo; Li, Baowen

    2013-01-01

    We studied how the period length and the mass ratio affect the thermal conductivity of isotopic nanoscale three-dimensional (3D) phononic crystal of Si. Simulation results by equilibrium molecular dynamics show isotopic nanoscale 3D phononic crystals can significantly reduce the thermal conductivity of bulk Si at high temperature (1000 K), which leads to a larger ZT than unity. The thermal conductivity decreases as the period length and mass ratio increases. The phonon dispersion curves show an obvious decrease of group velocities in 3D phononic crystals. The phonon's localization and band gap is also clearly observed in spectra of normalized inverse participation ratio in nanoscale 3D phononic crystal. PMID:23378898

  10. Basis for Coupled 3-D Neutronics and Thermal-Hydraulics

    The purpose of this seminar is first to discuss the basis of the coupling between 3-D Neutron- Kinetics and Thermal-Hydraulics codes, including the control and 3-D variables to interchange, the transform of the 3-D NK and TH core nodalizations, and the schemes for temporal coupling and time-step control. As representative examples of the NK-TH core coupling, we discuss first the integration of a 3-D NK nodal code with a TH subchannel code, for detailed transient core analysis; and second the coupling of 3-D NK nodal codes with TH system codes, for general transient and safety analysis. In chapter 2, we analyze several prototype model transients in PWR, where large 3-D core asymmetries are found and the NK-TH coupling is quite significant, including loss-of-flow and symmetric and asymmetric core cooling, considering the effects on the responses of the excore detectors. In chapter 3, we discuss the analysis of an increase-of-flow transient actually occurred in an operating PWR and the comparison with the measured data. In chapter 4, we summarize the phenomena and results of the calculations of the NEA/NSC Benchmark on the main steam line break (MSLB) transient in a PWR. Finally, we will discuss the state-of-the-art issues in LWR coupled NK-TH 3-D transient analysis and ongoing and planned computational developments.

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

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

  12. Multimodal Registration and Fusion for 3D Thermal Imaging

    Moulay A. Akhloufi; Benjamin Verney

    2015-01-01

    3D vision is an area of computer vision that has attracted a lot of research interest and has been widely studied. In recent years we witness an increasing interest from the industrial community. This interest is driven by the recent advances in 3D technologies, which enable high precision measurements at an affordable cost. With 3D vision techniques we can conduct advanced manufactured parts inspections and metrology analysis. However, we are not able to detect subsurface defects. This kind ...

  13. Performance Evaluation of 3d Modeling Software for Uav Photogrammetry

    Yanagi, H.; Chikatsu, H.

    2016-06-01

    UAV (Unmanned Aerial Vehicle) photogrammetry, which combines UAV and freely available internet-based 3D modeling software, is widely used as a low-cost and user-friendly photogrammetry technique in the fields such as remote sensing and geosciences. In UAV photogrammetry, only the platform used in conventional aerial photogrammetry is changed. Consequently, 3D modeling software contributes significantly to its expansion. However, the algorithms of the 3D modelling software are black box algorithms. As a result, only a few studies have been able to evaluate their accuracy using 3D coordinate check points. With this motive, Smart3DCapture and Pix4Dmapper were downloaded from the Internet and commercial software PhotoScan was also employed; investigations were performed in this paper using check points and images obtained from UAV.

  14. Thermal and mechanical properties of selected 3D printed thermoplastics in the cryogenic temperature regime

    Weiss, K.-P.; Bagrets, N.; Lange, C.; Goldacker, W.; Wohlgemuth, J.

    2015-12-01

    Insulating materials for use in cryogenic boundary conditions are still limited to a proved selection as Polyamid, Glasfiber reinforced resins, PEEK, Vespel etc. These materials are usually formed to parts by mechanical machining or sometimes by cast methods. Shaping complex geometries in one piece is limited. Innovative 3D printing is now an upcoming revolutionary technology to construct functional parts from a couple of thermoplastic materials as ABS, Nylon and others which possess quite good mechanical stability and allow realizing very complex shapes with very subtle details. Even a wide range of material mixtures is an option and thermal treatments can be used to finish the material structure for higher performance. The use of such materials in cryogenic environment is very attractive but so far poor experience exists. In this paper, first investigations of the thermal conductivity, expansion and mechanical strength are presented for a few selected commercial 3D material samples to evaluate their application prospects in the cryogenic temperature regime.

  15. Plastinated fetus: 3D CT scan (VRT) evaluation

    Shilpi Tiwari; Nandlal, B; N M Shama Sundar

    2012-01-01

    Objective: The intent of this study was to evaluate the effect of plastination on the morphology and structure of stored organs, to find out how much accuracy a plastinated specimen has, and to look into the changes that occurred because of plastination. Materials and Methods: A human fetus of gestational age 24 weeks was plastinated, and 3D CT scan evaluation of the fetus was done. Results: The results showed normal, well-defined, clearly identifiable organs, with no alteration in morp...

  16. 3D thermal modeling of TRISO fuel coupled with neutronic simulation

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

    2010-01-01

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

  17. Validation of thermal-hydraulic computing model of VVER-1000 Temelin NPP for coupled DYN3D/ATHLET codes

    This paper contains a description and evaluation of the thermal-hydraulic calculation of the transient connected with steam dump to atmosphere (SDA) opening during decreased reactor power to 20 % of nominal power (Nnom). The calculation was performed with the thermal-hydraulic system program ATHLET coupled with 3-D reactor dynamic code DYN3D. A comparison with the experiment was performed on the base of measured values during the SDA project function test on the VVER-1000 Temelin NPP Unit 2. Results obtained from calculated vs. experimental values could contribute to the validation of DYN3D/ATHLET coupling. (author)

  18. Prospective comparison of 3D FIESTA versus fat-suppressed 3D SPGR MRI in evaluating knee cartilage lesions

    Aim: To prospectively compare the accuracy of three-dimensional fast imaging employing steady-state acquisition (3D FIESTA) sequences with that of fat-suppressed three-dimensional spoiled gradient-recalled (3D SPGR) in the diagnosis of knee articular cartilage lesions, using arthroscopy as the reference standard. Materials and methods: Fifty-eight knees in 54 patients (age range 21-82 years; mean 36 years) were prospectively evaluated by using sagittal 3D FIESTA and sagittal fat-suppressed 3D SPGR sequences. Articular cartilage lesions were graded on MRI and during arthroscopy with a modified Noyes scoring system. Sensitivity, specificity, and accuracy were assessed. Interobserver agreement was determined with κ statistics. Results: The performance of 3D FIESTA sequences (sensitivity, specificity, and accuracy were 80, 94, and 92%, respectively, for reader 1 and 76, 94, and 90%, respectively, for reader 2) was similar to that of fat-suppressed 3D SPGR sequences (sensitivity, specificity, and accuracy were 82, 92, and 90%, respectively, for reader 1 and 82, 90, and 88%, respectively, for reader 2) in the detection of knee articular cartilage lesions. The interobserver agreement varied from fair to good to excellent (kappa values from 0.43-0.83). Conclusion: 3D FIESTA has good diagnostic performance, comparable with fat-suppressed 3D SPGR in evaluating knee cartilage lesions, and it can be incorporated into routine knee MRI protocols due to the short acquisition time.

  19. Coupled fully 3D neutron kinetics thermal-hydraulic computations for DNB analysis on PWRs

    Departure from Nucleate Boiling (DNB) is one of the major limiting factors of Pressurized Water Reactors (PWRs). Safety requires that occurrence of DNB should be precluded under normal or incidental operating conditions. To perform Main Steam Line Break (MSLB) accident calculations EDF have developed its own numerical tool OSCARD based on: the thermal-hydraulic THYC code for DNB analysis, the neutron kinetics COCCINELLE code for power distribution computations, the thermal-hydraulic CATHARE code to provide boundary conditions analysis with system scale computation. With OSCARD a fully three-dimensional (3D) representation of the core is proposed in conjunction with a two-phase flow porous-body approach (THYC) and two-group diffusion equations in the axial and lateral directions with Doppler and void reactivity feedback effects (COCCINELLE). OSCARD provides EDF with an alternative and independent way of evaluating fuel performance and safety margins. In the licensed approach, the coupled 3D neutron kinetics and thermal-hydraulic part of OSCARD steady computations is used to produce 3D power distribution in the reactor core at the most penalizing moment of the transient. Then this distribution is used as an input for THYC to perform thermal-hydraulic subchannel analysis. This 3 steps approach is used with simple conservative and bounding analysis assumptions, that can not occur in reality. In a prospective approach, OSCARD enables to combine thermal-hydraulic subchannel analysis with the neutron kinetics radial average channel model using a nodalization of one quarter of fuel assembly in order to perform one step DNB analysis. (author)

  20. Development of two-phase flow analysis system for increasing thermal efficiency of power plant. (1) 3D analysis for evaluating the thermal-hydraulic behavior in secondary side of the steam generator

    For upgrades of nuclear power plant with pressurized water reactor, it is one of the effective mean to improve the steam generator (SG) secondary flow. To evaluate thermal-fluid dynamics in secondary system of SG, boiling two-phase phenomenon is needed to analyze. In this study, new numerical analysis system is developing for PWR secondary system including SG and turbine system. Firstly three dimensional two-phase flow analysis model of SG secondary-side is developed with two-fluid model, and we confirm that our model can estimate steam pressure of feeding type SG. Secondary present model is applied to preheat type SG and evaluate the effect of increasing of steam pressure in secondary-side. From this result, we succeeded in predicting the steam pressure increase with improving the method of feedwater supply. (author)

  1. 3D printing of new biobased unsaturated polyesters by microstereo-thermal-lithography

    New micro three-dimensional (3D) scaffolds using biobased unsaturated polyesters (UPs) were prepared by microstereo-thermal-lithography (μSTLG). This advanced processing technique offers indubitable advantages over traditional printing methods. The accuracy and roughness of the 3D structures were evaluated by scanning electron microscopy and infinite focus microscopy, revealing a suitable roughness for cell attachment. UPs were synthesized by bulk polycondensation between biobased aliphatic diacids (succinic, adipic and sebacic acid) and two different glycols (propylene glycol and diethylene glycol) using fumaric acid as the source of double bonds. The chemical structures of the new oligomers were confirmed by proton nuclear magnetic resonance spectra, attenuated total reflectance Fourier transform infrared spectroscopy and matrix assisted laser desorption/ionization-time of flight mass spectrometry. The thermal and mechanical properties of the UPs were evaluated to determine the influence of the diacid/glycol ratio and the type of diacid in the polyester’s properties. In addition an extensive thermal characterization of the polyesters is reported. The data presented in this work opens the possibility for the use of biobased polyesters in additive manufacturing technologies as a route to prepare biodegradable tailor made scaffolds that have potential applications in a tissue engineering area. (paper)

  2. 3D Distribution of Significant Oscillations in Thermal Plasma Jet

    Gruber, Jan; Sekerešová, Zuzana; Hlína, Jan; Šonský, Jiří

    Greifswald : Leibniz Institute, 2010, s. 548-551. ISBN 0-9539105-4-7. [International Conference on Gas Discharges and their Applications /18./. Greifswald (DE), 05.09.2010-10.09.2010] Institutional research plan: CEZ:AV0Z20570509 Keywords : plasma torch * thermal plasma * PSD Subject RIV: BL - Plasma and Gas Discharge Physics

  3. Study of the thermal properties of filaments for 3D printing

    Trhlíková, Lucie; Zmeskal, Oldrich; Psencik, Petr; Florian, Pavel

    2016-07-01

    Various materials are used for 3D printing, most commonly Acrylonitrile butadiene styrene (ABS), Polylactic acid (PLA), Polyethylene (PET) and Polypropylene (PP). These materials differ mainly in their melting point, which significantly influences the properties of the final products. Filaments are melted in the print head during the printing process. The temperature range is from 150 °C to 250 °C depending on the technology used. The optimum temperature for the cooling substrate on which printing is carried out is chosen so as to ensure uniform cooling and deformation. It generally varies between (40 - 100) °C. From the above it is clear that both temperatures can significantly affect the properties of the printed 3D object. It is therefore important to determine the thermal parameters (thermal conductivity, specific heat and thermal diffusivity) of the materials used across the entire range of temperatures. For evaluating the properties of different types of PLA materials, the step transient method was used, which allows determination of all required parameters using a fractal heat transfer model.

  4. Development of a coupled 1D-3D thermal-hydraulic code for nuclear power plant simulation and its application to a pressurized thermal shock scenario in PWR

    Thermal-hydraulic (TH) system codes are developed for the evaluation and improvement of the design and safety of nuclear facilities. Since the numerical modeling of the thermal-hydraulic processes is 1D in nature, these programs have only limited capabilities to predict in detail 3D flows and coolant mixing processes. In contrast, computational fluid dynamics (CFD) software tools are used for 3D flow calculations with high spatial resolution. In order to realistically and efficiently simulate the thermal-hydraulic phenomena in a nuclear power plant (NPP), GRS has developed a methodology for the coupling of the TH system code ATHLET with the 3D CFD software ANSYS CFX. Within the European project NURISP validation activities for the 1D-3D code ATHLET - ANSYS CFX based on a Pressurized Thermal Shock (PTS) related experiment are performed. (author)

  5. Evaluation of vision training using 3D play game

    Kim, Jung-Ho; Kwon, Soon-Chul; Son, Kwang-Chul; Lee, Seung-Hyun

    2015-03-01

    The present study aimed to examine the effect of the vision training, which is a benefit of watching 3D video images (3D video shooting game in this study), focusing on its accommodative facility and vergence facility. Both facilities, which are the scales used to measure human visual performance, are very important factors for man in leading comfortable and easy life. This study was conducted on 30 participants in their 20s through 30s (19 males and 11 females at 24.53 ± 2.94 years), who can watch 3D video images and play 3D game. Their accommodative and vergence facility were measured before and after they watched 2D and 3D game. It turned out that their accommodative facility improved after they played both 2D and 3D games and more improved right after they played 3D game than 2D game. Likewise, their vergence facility was proved to improve after they played both 2D and 3D games and more improved soon after they played 3D game than 2D game. In addition, it was demonstrated that their accommodative facility improved to greater extent than their vergence facility. While studies have been so far conducted on the adverse effects of 3D contents, from the perspective of human factor, on the imbalance of visual accommodation and convergence, the present study is expected to broaden the applicable scope of 3D contents by utilizing the visual benefit of 3D contents for vision training.

  6. General 3D Lumped Thermal Model with Various Boundary Conditions for High Power IGBT Modules

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    2016-01-01

    Accurate thermal dynamics modeling of high power Insulated Gate Bipolar Transistor (IGBT) modules is important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated...... thermal behaviors in the IGBTs. In this paper, a new three-dimensional (3D) lumped thermal model is proposed, which can easily be characterized from Finite Element Methods (FEM) based simulation and acquire the thermal distribution in critical points. Meanwhile the boundary conditions including the...... cooling system and power losses are modeled in the 3D thermal model, which can be adapted to different real field applications of power electronic converters. The accuracy of the proposed thermal model is verified by experimental results....

  7. PERFORMANCE EVALUATION OF 3D MODELING SOFTWARE FOR UAV PHOTOGRAMMETRY

    Yanagi, H; H. Chikatsu

    2016-01-01

    UAV (Unmanned Aerial Vehicle) photogrammetry, which combines UAV and freely available internet-based 3D modeling software, is widely used as a low-cost and user-friendly photogrammetry technique in the fields such as remote sensing and geosciences. In UAV photogrammetry, only the platform used in conventional aerial photogrammetry is changed. Consequently, 3D modeling software contributes significantly to its expansion. However, the algorithms of the 3D modelling software are black box algori...

  8. Performance evaluation of 3D-TV systems

    kaptein, R.G.; Kuijsters, A.; Lambooij, M.T.M.; IJsselsteijn, W.A.; Heynderickx, I.

    2008-01-01

    The image quality circle is a commonly accepted framework to model the relation between the technology variables of a display and the resulting image quality. 3D-TV systems, however, go beyond the concept of image quality. Research has shown that, although 3D scenes are clearly more appreciated by s

  9. [Evaluation of Motion Sickness Induced by 3D Video Clips].

    Matsuura, Yasuyuki; Takada, Hiroki

    2016-01-01

    The use of stereoscopic images has been spreading rapidly. Nowadays, stereoscopic movies are nothing new to people. Stereoscopic systems date back to 280 A.D. when Euclid first recognized the concept of depth perception by humans. Despite the increase in the production of three-dimensional (3D) display products and many studies on stereoscopic vision, the effect of stereoscopic vision on the human body has been insufficiently understood. However, symptoms such as eye fatigue and 3D sickness have been the concerns when viewing 3D films for a prolonged period of time; therefore, it is important to consider the safety of viewing virtual 3D contents as a contribution to society. It is generally explained to the public that accommodation and convergence are mismatched during stereoscopic vision and that this is the main reason for the visual fatigue and visually induced motion sickness (VIMS) during 3D viewing. We have devised a method to simultaneously measure lens accommodation and convergence. We used this simultaneous measurement device to characterize 3D vision. Fixation distance was compared between accommodation and convergence during the viewing of 3D films with repeated measurements. Time courses of these fixation distances and their distributions were compared in subjects who viewed 2D and 3D video clips. The results indicated that after 90 s of continuously viewing 3D images, the accommodative power does not correspond to the distance of convergence. In this paper, remarks on methods to measure the severity of motion sickness induced by viewing 3D films are also given. From the epidemiological viewpoint, it is useful to obtain novel knowledge for reduction and/or prevention of VIMS. We should accumulate empirical data on motion sickness, which may contribute to the development of relevant fields in science and technology. PMID:26832611

  10. TORT-TD/ATTICA3D: a coupled neutron transport and thermal hydraulics code system for 3-D transient analysis of gas cooled high temperature reactors

    Comprehensive safety studies of high temperature gas cooled reactors (HTR) require full three dimensional coupled treatments of both neutron kinetics and thermal-hydraulics. In a common effort, GRS and IKE developed the coupled code system TORT-TD/ATTICA3D for pebble bed type HTR that connects the 3-D transient discrete-ordinates transport code TORT-TD with the 3-D porous medium thermal-hydraulics code ATTICA3D. In this paper, the physical models and calculation capabilities of TORT-TD and ATTICA3D are presented, focusing on model improvements in ATTICA3D and extensions made in TORT-TD related to HTR application. For first applications, the OECD/NEA/NSC PBMR-400 benchmark has been chosen. Results obtained with TORT-TD/ATTICA3D will be shown for transient exercises, e.g. control rod withdrawal and a control rod ejection. Results are compared to other benchmark participants' solutions with special focus on fuel temperature modelling features of ATTICA3D. The provided “grey-curtain” nuclear cross section libraries have been used. First results on 3-D effects during a control rod withdrawal transient will be presented. (author)

  11. Computation of thermal properties via 3D homogenization of multiphase materials using FFT-based accelerated scheme

    Lemaitre, Sophie; Choi, Daniel; Karamian, Philippe

    2015-01-01

    In this paper we study the thermal effective behaviour for 3D multiphase composite material consisting of three isotropic phases which are the matrix, the inclusions and the coating media. For this purpose we use an accelerated FFT-based scheme initially proposed in Eyre and Milton (1999) to evaluate the thermal conductivity tensor. Matrix and spherical inclusions media are polymers with similar properties whereas the coating medium is metallic hence better conducting. Thus, the contrast between the coating and the others media is very large. For our study, we use RVEs (Representative volume elements) generated by RSA (Random Sequential Adsorption) method developed in our previous works, then, we compute effective thermal properties using an FFT-based homogenization technique validated by comparison with the direct finite elements method. We study the thermal behaviour of the 3D-multiphase composite material and we show what features should be taken into account to make the computational approach efficient.

  12. Development of 3D Woven Ablative Thermal Protection Systems (TPS) for NASA Spacecraft

    Feldman, Jay D.; Ellerby, Don; Stackpoole, Mairead; Peterson, Keith; Venkatapathy, Ethiraj

    2015-01-01

    The development of a new class of thermal protection system (TPS) materials known as 3D Woven TPS led by the Entry Systems and Technology Division of NASA Ames Research Center (ARC) will be discussed. This effort utilizes 3D weaving and resin infusion technologies to produce heat shield materials that are engineered and optimized for specific missions and requirements. A wide range of architectures and compositions have been produced and preliminarily tested to prove the viability and tailorability of the 3D weaving approach to TPS.

  13. Anisotropic thermal expansion of a 3D metal–organic framework with hydrophilic and hydrophobic pores

    A 3D flexible metal–organic framework (MOF) with 1D hydrophilic and hydrophobic pores shows anisotropic thermal expansion with relatively large thermal expansion coefficient (αa=−21×10−6 K−1 and αc=79×10−6 K−1) between 133 K and 383 K. Temperature change gives deformation of both pores, which expand in diameter and elongate in length on cooling and vice versa. The thermally induced structural change should be derived from a unique framework topology like “lattice fence”. Silica accommodation changes not only the nature of the MOF but also thermal responsiveness of the MOF. Since the hydrophobic pores in the material are selectively blocked by the silica, the MOF with the silica is considered as a hydrophilic microporous material. Furthermore, inclusion of silica resulted in a drastic pore contraction in diameter and anisotropically changed the thermal responsiveness of the MOF. - Graphical abstract: A 3D metal–organic framework with hydrophilic and hydrophobic pores shows anisotropic thermal expansion behavior. The influence of silica filler in the hydrophobic pore was investigated. - Highlights: • Thermally induced structural change of a 3D MOF with a lattice fence topology was investigated. • The structural change was analyzed by synchrotron X-ray diffraction patterns. • Temperature change induces anisotropic thermal expansion/contraction of the MOF. • Silica inclusion anisotropically changes the thermal responsiveness of the MOF

  14. Anisotropic thermal expansion of a 3D metal–organic framework with hydrophilic and hydrophobic pores

    Kondo, Atsushi, E-mail: kondoa@cc.tuat.ac.jp; Maeda, Kazuyuki

    2015-01-15

    A 3D flexible metal–organic framework (MOF) with 1D hydrophilic and hydrophobic pores shows anisotropic thermal expansion with relatively large thermal expansion coefficient (α{sub a}=−21×10{sup −6} K{sup −1} and α{sub c}=79×10{sup −6} K{sup −1}) between 133 K and 383 K. Temperature change gives deformation of both pores, which expand in diameter and elongate in length on cooling and vice versa. The thermally induced structural change should be derived from a unique framework topology like “lattice fence”. Silica accommodation changes not only the nature of the MOF but also thermal responsiveness of the MOF. Since the hydrophobic pores in the material are selectively blocked by the silica, the MOF with the silica is considered as a hydrophilic microporous material. Furthermore, inclusion of silica resulted in a drastic pore contraction in diameter and anisotropically changed the thermal responsiveness of the MOF. - Graphical abstract: A 3D metal–organic framework with hydrophilic and hydrophobic pores shows anisotropic thermal expansion behavior. The influence of silica filler in the hydrophobic pore was investigated. - Highlights: • Thermally induced structural change of a 3D MOF with a lattice fence topology was investigated. • The structural change was analyzed by synchrotron X-ray diffraction patterns. • Temperature change induces anisotropic thermal expansion/contraction of the MOF. • Silica inclusion anisotropically changes the thermal responsiveness of the MOF.

  15. Accuracy evaluation of 3D lidar data from small UAV

    Tulldahl, H. M.; Bissmarck, Fredrik; Larsson, Hâkan; Grönwall, Christina; Tolt, Gustav

    2015-10-01

    A UAV (Unmanned Aerial Vehicle) with an integrated lidar can be an efficient system for collection of high-resolution and accurate three-dimensional (3D) data. In this paper we evaluate the accuracy of a system consisting of a lidar sensor on a small UAV. High geometric accuracy in the produced point cloud is a fundamental qualification for detection and recognition of objects in a single-flight dataset as well as for change detection using two or several data collections over the same scene. Our work presented here has two purposes: first to relate the point cloud accuracy to data processing parameters and second, to examine the influence on accuracy from the UAV platform parameters. In our work, the accuracy is numerically quantified as local surface smoothness on planar surfaces, and as distance and relative height accuracy using data from a terrestrial laser scanner as reference. The UAV lidar system used is the Velodyne HDL-32E lidar on a multirotor UAV with a total weight of 7 kg. For processing of data into a geographically referenced point cloud, positioning and orientation of the lidar sensor is based on inertial navigation system (INS) data combined with lidar data. The combination of INS and lidar data is achieved in a dynamic calibration process that minimizes the navigation errors in six degrees of freedom, namely the errors of the absolute position (x, y, z) and the orientation (pitch, roll, yaw) measured by GPS/INS. Our results show that low-cost and light-weight MEMS based (microelectromechanical systems) INS equipment with a dynamic calibration process can obtain significantly improved accuracy compared to processing based solely on INS data.

  16. In Situ Thermal Generation of Silver Nanoparticles in 3D Printed Polymeric Structures

    Erika Fantino

    2016-07-01

    Full Text Available Polymer nanocomposites have always attracted the interest of researchers and industry because of their potential combination of properties from both the nanofillers and the hosting matrix. Gathering nanomaterials and 3D printing could offer clear advantages and numerous new opportunities in several application fields. Embedding nanofillers in a polymeric matrix could improve the final material properties but usually the printing process gets more difficult. Considering this drawback, in this paper we propose a method to obtain polymer nanocomposites by in situ generation of nanoparticles after the printing process. 3D structures were fabricated through a Digital Light Processing (DLP system by disolving metal salts in the starting liquid formulation. The 3D fabrication is followed by a thermal treatment in order to induce in situ generation of metal nanoparticles (NPs in the polymer matrix. Comprehensive studies were systematically performed on the thermo-mechanical characteristics, morphology and electrical properties of the 3D printed nanocomposites.

  17. 3D multidetector CT angiographic evaluation of intralobular bronchopulmonary sequestration

    Marwah Ruchira

    2010-01-01

    Full Text Available We report a case of intralobar pulmonary sequestration with special emphasis on computed tomography (CT angiography in determining the arterial supply and venous drainage, thus providing a detailed knowledge of the vasculature, which is of vital importance in surgery. The 3D volume rendering technique and maximum intensity projection images provide the vascular road map for the surgeon.

  18. Estimation of the thermal conductivity of hemp based insulation material from 3D tomographic images

    El-Sawalhi, R.; Lux, J.; Salagnac, P.

    2016-08-01

    In this work, we are interested in the structural and thermal characterization of natural fiber insulation materials. The thermal performance of these materials depends on the arrangement of fibers, which is the consequence of the manufacturing process. In order to optimize these materials, thermal conductivity models can be used to correlate some relevant structural parameters with the effective thermal conductivity. However, only a few models are able to take into account the anisotropy of such material related to the fibers orientation, and these models still need realistic input data (fiber orientation distribution, porosity, etc.). The structural characteristics are here directly measured on a 3D tomographic image using advanced image analysis techniques. Critical structural parameters like porosity, pore and fiber size distribution as well as local fiber orientation distribution are measured. The results of the tested conductivity models are then compared with the conductivity tensor obtained by numerical simulation on the discretized 3D microstructure, as well as available experimental measurements. We show that 1D analytical models are generally not suitable for assessing the thermal conductivity of such anisotropic media. Yet, a few anisotropic models can still be of interest to relate some structural parameters, like the fiber orientation distribution, to the thermal properties. Finally, our results emphasize that numerical simulations on 3D realistic microstructure is a very interesting alternative to experimental measurements.

  19. A subjective experiment for 3D-mesh segmentation evaluation

    Benhabiles, Halim; Lavoué, Guillaume; Vandeborre, Jean-Philippe; Daoudi, Mohamed

    2010-01-01

    In this paper we present a subjective quality assessment experiment for 3D-mesh segmentation. For this end, we carefully designed a protocol with respect to several factors namely the rendering conditions, the possible interactions, the rating range, and the number of human subjects. To carry out the subjective experiment, more than 40 human observers have rated a set of 250 segmentation results issued from various algorithms. The obtained Mean Opinion Scores, which represent the human subjec...

  20. Outcome evaluation in shoulder surgery using 3D kinematics sensors

    Coley, B.; Jolles, B.; Farron, A.; Bourgeois, A; Nussbaumer, F.; Pichonnaz, C.; Aminian, K.

    2007-01-01

    A new method of scoring systems for the functional assessment of the shoulder is presented. 3D accelerometers and gyroscopes attached on the humerus were used to differentiate a healthy from a painful shoulder. The method was first tested on 10 healthy volunteer subjects without any shoulder pathologies. Then, the system was tested on 10 patients with unilateral shoulder pathology (rotator cuff disease, osteoarthritis) before and after surgery (3, 6 months). To evalua...

  1. First vapor explosion calculations performed with MC3D thermal-hydraulic code

    Brayer, C.; Berthoud, G. [CEA Centre d`Etudes de Grenoble, 38 (France). Direction des Reacteurs Nucleaires

    1998-01-01

    This paper presents the first calculations performed with the `explosion` module of the multiphase computer code MC3D, which is devoted to the fine fragmentation and explosion phase of a fuel coolant interaction. A complete description of the physical laws included in this module is given. The fragmentation models, taking into account two fragmentation mechanisms, a thermal one and an hydrodynamic one, are also developed here. Results to some calculations to test the numerical behavior of MC3D and to test the explosion models in 1D or 2D are also presented. (author)

  2. Three-dimensional (3-D) thermal investigation below high Alpine topography

    Kohl, T.; Signorelli, S.; Rybach, L.

    2001-11-01

    The characteristics of severe topography in active mountain belts represent a special challenge for the evaluation of subsurface temperatures. These conditions require in particular a proper treatment of possible thermally relevant mechanisms. In the present analysis temperature data from depths of up to 1.5 km are investigated which have been collected at the intermediate "point-of-attack" in the framework of the new Alpine transverse (NEAT) project in central Switzerland for the construction of a 57 km long base tunnel. Specially designed temperature measurements were used in a 800 m deep shaft and along a 1200 m long access adit. Additional thermal information was provided by temperature logs from two nearby exploration boreholes and from laboratory measurements of various samples. For a detailed investigation of the temperature data a transient finite element (FE) model has been used which accounts for fluid and mass advection (uplift) as well as for climatic changes. The uplift and exhumation scenario assumed the surface to be in steady-state conditions. Special emphasis was given to structural effects like topography and anisotropy. The 3-D numerical model extends over an area of ˜ 20 km×20 km and includes Alpine high topographic relief with altitudes between 1500 and 3000 m a.s.l. Without modifying petrophysical parameters determined from laboratory measurements, all reliable temperature data could be nearly perfectly fitted by adjusting the two principal thermal boundary conditions at the surface and at the bottom. This study reveals that hydraulic influence is generally negligible at depths below ˜500 m which is in contrast to results from lower-dimensional methods such as 1-D Péclet analyses. Vertical heat flow variations are rather due to topographic than to hydraulic impact. Sensitivity studies highlight the importance of uplift in the central Swiss Alps and of local ground surface temperature (GST) distribution which both can influence the

  3. 3D structure and conductive thermal field of the Upper Rhine Graben

    Freymark, Jessica; Sippel, Judith; Scheck-Wenderoth, Magdalena; Bär, Kristian; Stiller, Manfred; Fritsche, Johann-Gerhard; Kracht, Matthias

    2016-04-01

    The Upper Rhine Graben (URG) was formed as part of the European Cenozoic Rift System in a complex extensional setting. At present-day, it has a large socioeconomic relevance as it provides a great potential for geothermal energy production in Germany and France. For the utilisation of this energy resource it is crucial to understand the structure and the observed temperature anomalies in the rift basin. In the framework of the EU-funded "IMAGE" project (Integrated Methods for Advanced Geothermal Exploration), we apply a data-driven numerical modelling approach to quantify the processes and properties controlling the spatial distribution of subsurface temperatures. Typically, reservoir-scale numerical models are developed for predictions on the subsurface hydrothermal conditions and for reducing the risk of drilling non-productive geothermal wells. One major problem related to such models is setting appropriate boundary conditions that define, for instance, how much heat enters the reservoir from greater depths. Therefore, we first build a regional lithospheric-scale 3D structural model, which covers not only the entire URG but also adjacent geological features like the Black Forest and the Vosges Mountains. In particular, we use a multidisciplinary dataset (e.g. well data, seismic reflection data, existing structural models, gravity) to construct the geometries of the sediments, the crust and the lithospheric mantle that control the spatial distribution of thermal conductivity and radiogenic heat production and hence temperatures. By applying a data-based and lithology-dependent parameterisation of this lithospheric-scale 3D structural model and a 3D finite element method, we calculate the steady-state conductive thermal field for the entire region. Available measured temperatures (down to depths of up to 5 km) are considered to validate the 3D thermal model. We present major characteristics of the lithospheric-scale 3D structural model and results of the 3D

  4. Cookoff Response of PBXN-109: Material Characterization and ALE3D Thermal Predictions

    McClelland, M A; Tran, T D; Cunningham, B J; Weese, R K; Maienschein, J L

    2001-05-29

    Materials properties measurements are made for the RDX-based explosive, PBXN-109, and initial ALE3D model predictions are given for the cookoff temperature in a U.S. Navy test. This work is part of an effort in the U.S. Navy and Department of Energy (DOE) laboratories to understand the thermal explosion behavior of this material. Benchmark cookoff experiments are being performed by the U.S. Navy to validate DOE materials models and computer codes. The ALE3D computer code can model the coupled thermal, mechanical, and chemical behavior of heating, ignition, and explosion in cookoff tests. In our application, a standard three-step step model is selected for the chemical kinetics. The strength behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the Equation Of State (EOS) for the solid and gas species, respectively. Materials characterization measurements are given for thermal expansion, heat capacity, shear modulus, bulk modulus, and One-Dimensional-Time-to-Explosion (ODTX). These measurements and those of the other project participants are used to determine parameters in the ALE3D chemical, mechanical, and thermal models. Time-dependent, two-dimensional results are given for the temperature and material expansion. The results show predicted cookoff temperatures slightly higher than the measured values.

  5. Cookoff Response of PBXN-109: Material Characterization and ALE3D Thermal Predictions

    McClelland, M A; Tran, T D; Cunningham, B J; Weese, R K; Maienschein, J L

    2001-08-21

    Materials properties measurements are made for the RDX-based explosive, PBXN-109, and initial ALE3D model predictions are given for the cookoff temperature in a U.S. Navy test. This work is part of an effort in the U.S. Navy and Department of Energy (DOE) laboratories to understand the thermal explosion behavior of this material. Benchmark cookoff experiments are being performed by the U.S. Navy to validate DOE materials models and computer codes. The ALE3D computer code can model the coupled thermal, mechanical, and chemical behavior of heating, ignition, and explosion in cookoff tests. In our application, a standard three-step step model is selected for the chemical kinetics. The strength behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the Equation Of State (EOS) for the solid and gas species, respectively. Materials characterization measurements are given for thermal expansion, heat capacity, shear modulus, bulk modulus, and One-Dimensional-Time-to-Explosion (ODTX). These measurements and those of the other project participants are used to determine parameters in the ALE3D chemical, mechanical, and thermal models. Time-dependent, two-dimensional results are given for the temperature and material expansion. The results show predicted cookoff temperatures slightly higher than the measured values.

  6. Thermal characterization of a liquid resin for 3D printing using photothermal techniques

    Jiménez-Pérez, José L.; Pincel, Pavel Vieyra; Cruz-Orea, Alfredo; Correa-Pacheco, Zormy N.

    2016-05-01

    Thermal properties of a liquid resin were studied by thermal lens spectrometry (TLS) and open photoacoustic cell (OPC), respectively. In the case of the TLS technique, the two mismatched mode experimental configuration was used with a He-Ne laser, as a probe beam and an Argon laser was used as the excitation source. The characteristic time constant of the transient thermal lens was obtained by fitting the theoretical expression to the experimental data in order to obtain the thermal diffusivity ( α) of the resin. On the other hand, the sample thermal effusivity ( e) was obtained by using the OPC technique. In this technique, an Argon laser was used as the excitation source and was operated at 514 nm with an output power of 30 mW. From the obtained thermal diffusivity ( α) and thermal effusivity ( e) values, the thermal conductivity ( k) and specific heat capacity per unit volume ( ρc) of resin were calculated through the relationships k = e( α)1/2 and ρc = e/( α)1/2. The obtained thermal parameters were compared with the thermal parameters of the literature. To our knowledge, the thermal characterization of resin has not been reported until now. The present study has applications in laser stereo-lithography to manufacture 3D printing pieces.

  7. International training program in support of safety analysis: 3D S.UN.COP - Scaling, uncertainty and 3D thermal-hydraulics/neutron-kinetics coupled codes seminars

    The best estimate thermal-hydraulic codes used in the area of nuclear reactor safety have reached a marked level of sophistication and they require to be used by competent analysts. The need for user qualification and training is clearly recognized. An effort is being made to develop a proposal for a systematic approach to user training. The estimated duration of training at the course venue, including a set of training seminars, workshops, and practical exercises, is approximately two years. In addition, the specification and assignment of tasks to be performed by the participants at their home institutions, with continuous supervision from the training center, has been foreseen. The 3D S.UN.COP seminars constitute the follow-up of the presented proposal. The seminar is subdivided into three main parts, each of one with a program to be developed in one week: the first week is dedicated to fundamental theoretical aspects, the second week deals with industrial application, coupling methodologies and hands-on training, and the third week focuses on training for transient analysis in the interaction between thermal-hydraulics and fuel behaviour. The responses of the participants during the training have demonstrated an increase in the capabilities to develop and/or modify nodalization and to perform a qualitative and quantitative accuracy evaluation. It is expected that the participants will be able to set up more accurate, reliable and efficient simulation models, applying the procedures for qualifying the thermal-hydraulic system code calculations, and for the evaluation of the uncertainty

  8. Extreme low thermal conductivity in nanoscale 3D Si phononic crystal with spherical pores.

    Yang, Lina; Yang, Nuo; Li, Baowen

    2014-01-01

    In this work, we propose a nanoscale three-dimensional (3D) Si phononic crystal (PnC) with spherical pores, which can reduce the thermal conductivity of bulk Si by a factor up to 10,000 times at room temperature. Thermal conductivity of Si PnCs depends on the porosity, for example, the thermal conductivity of Si PnCs with porosity 50% is 300 times smaller than that of bulk Si. The phonon participation ratio spectra demonstrate that more phonons are localized as the porosity increases. The thermal conductivity is insensitive to the temperature changes from room temperature to 1100 K. The extreme-low thermal conductivity could lead to a larger value of ZT than unity as the periodic structure affects very little the electric conductivity. PMID:24559126

  9. FDSOI bottom MOSFETs stability versus top transistor thermal budget featuring 3D monolithic integration

    Fenouillet-Beranger, C.; Previtali, B.; Batude, P.; Nemouchi, F.; Cassé, M.; Garros, X.; Tosti, L.; Rambal, N.; Lafond, D.; Dansas, H.; Pasini, L.; Brunet, L.; Deprat, F.; Grégoire, M.; Mellier, M.; Vinet, M.

    2015-11-01

    To set up specification for 3D monolithic integration, for the first time, the thermal stability of state-of-the-art FDSOI (Fully Depleted SOI) transistors electrical performance is quantified. Post fabrication annealings are performed on FDSOI transistors to mimic the thermal budget associated to top layer processing. Degradation of the silicide for thermal treatments beyond 400 °C is identified as the main responsible for performance degradation for PMOS devices. For the NMOS transistors, arsenic (As) and phosphorus (P) dopants deactivation adds up to this effect. By optimizing both the n-type extension implantations and the bottom silicide process, thermal stability of FDSOI can be extended to allow relaxing upwards the thermal budget authorized for top transistors processing.

  10. Evaluation of 3-D graphics software: A case study

    Lores, M. E.; Chasen, S. H.; Garner, J. M.

    1984-01-01

    An efficient 3-D geometry graphics software package which is suitable for advanced design studies was developed. The advanced design system is called GRADE--Graphics for Advanced Design. Efficiency and ease of use are gained by sacrificing flexibility in surface representation. The immediate options were either to continue development of GRADE or to acquire a commercially available system which would replace or complement GRADE. Test cases which would reveal the ability of each system to satisfy the requirements were developed. A scoring method which adequately captured the relative capabilities of the three systems was presented. While more complex multi-attribute decision methods could be used, the selected method provides all the needed information without being so complex that it is difficult to understand. If the value factors are modestly perturbed, system Z is a clear winner based on its overall capabilities. System Z is superior in two vital areas: surfacing and ease of interface with application programs.

  11. 3D Diagnostics of Coherent Structures in a Thermal Plasma Jet

    Hlína, Jan; Sekerešová, Zuzana; Šonský, Jiří

    Brno : Brno University of Technology, 2007, s. 93-96. ISBN 978-80-214-3359-5. [Symposium on Physics of Switching Arc - FSO 2007 /17./. Nové Město na Moravě (CZ), 10.09.2007-13.09.2007] R&D Projects: GA ČR GA202/05/0728 Institutional research plan: CEZ:AV0Z20570509 Keywords : coherent structure * thermal plasma jet * 3D reconstruction Subject RIV: BL - Plasma and Gas Discharge Physics

  12. Thermal-Aware Post Layout Voltage-Island Generation for 3D ICs

    Ning Xu; Yu-Chun Ma; Jia Liu; Shou-Chun Tao

    2013-01-01

    To reduce the interconnect delay and improve the chip performance,three-dimensional (3D) chip emerged with the rapid increasing of chip integration and chip power density.Therefore,thermal issue is one of the critical challenges in 3D IC design due to the high power density.Multiple Supply Voltages (MSV) technique provides an efficient way to optimize power consumption which in turn may alleviate the hotspots.But the voltage assignment is limited not only by the performance constraints of the design,but also by the physical layout of circuit modules since the modules with the same voltage should be gathered to reduce the power-network routing resource.Especially in 3D designs,the optimization using MSV technique becomes even more complicated since the high temperature also influences the power consumption and delay on paths.In this paper,we address the voltage-island generation problem for MSV designs in 3D ICs based on a mixed integer linear programming (MILP) model.First,we propose a general MILP formulation for voltage-island generation to optimize thermal distribution as well as power-network routing resources while maintaining the whole chip performance.With the thermal-power interdependency,an iterative optimization approach is proposed to obtain the convergence.Experimental results show that our thermal-aware voltage-island generation approach can reduce the maximal on-chip temperature by 23.64% with a reasonable runtime and save the power-network routing resources by 16.71%.

  13. 3D dynamics of hydrous thermal-chemical plumes in subduction zones

    Zhu, G.; Gerya, T.; Yuen, D.; Connolly, J. A. D.

    2009-04-01

    Mantle wedges are identified as sites of intense thermal convection and thermal-chemical Rayleigh-Taylor instabilities ("cold plumes") controlling distribution and intensity of magmatic activity in subduction zones. To investigate 3D hydrous partially molten cold plumes forming in the mantle wedge in response to slab dehydration, we perform 3D petrological-thermomechanical numerical simulations of the intraoceanic one-sided subduction with spontaneously bending retreating slab characterized by weak hydrated upper interface. I3ELVIS code is used which is developed based on multigrid approach combined with marker-in-cell method with conservative finite-difference schemes. We investigated regional 800 km wide and 200 km deep 3D subduction models with variable 200 to 800 km lateral dimension along the trench using uniform numerical staggered grid with 405x101x101 nodal points and up to 50 million markers. Our results show three patterns (roll(sheet)-, zig-zag- and finger-like) of Rayleigh-Taylor instabilities can develop above the subducting slab, which are controlled by effective viscosity of partially molten rocks. Spatial and temporal periodicity of plumes correlate well with that of volcanic activity in natural intraoceanic arcs such as Japan. High laterally variable surface heat flow predicted in the arc region in response to thermal-chemical plumes activity is also consistent with natural observations.

  14. An Exploratory Evaluation of User Interfaces for 3D Audio Mixing

    Gelineck, Steven; Korsgaard, Dannie Michael

    2015-01-01

    The paper presents an exploratory evaluation comparing different versions of a mid-air gesture based interface for mixing 3D audio exploring: (1) how such an interface generally compares to a more traditional physical interface, (2) methods for grabbing/releasing audio channels in mid-air and (3......) representation of sources in separate 3D views vs. in one shared 3D view. Results suggest that while the traditional physical interface is generally intuitive and easy to use, the 3D gesture interface provides an improved understanding of the 3D space and provides a better control of especially moving sources...

  15. Study of the initiation and the propagation of cracks under 3D thermal cyclic loading

    The incident which has occurred on the Civaux power plant has shown the noxiousness of thermal loading and the difficulty to take it into account at design level. The objective of this report is to study the initiation and the propagation of crack under thermal loading. In this aim the CEA has developed a new experiment named FAT3D. The various experiments carried out showed the harmfulness of a thermal loading, which makes it possible to rapidly initiate a network of cracks and to propagate one (or some) cracks through the totally thickness of the component under certain conditions. These experimental results associated with a mechanical analysis put at fault the usual criteria of damage based on the variations of the equivalent strain. In addition, the study of the propagation stage shows the importance of the plasticity which, in the case of a thermal loading, slows down the propagation of the crack. (author)

  16. First 3D thermal mapping of an active volcano using an advanced photogrammetric method

    Antoine, Raphael; Baratoux, David; Lacogne, Julien; Lopez, Teodolina; Fauchard, Cyrille; Bretar, Frédéric; Arab-Sedze, Mélanie; Staudacher, Thomas; Jacquemoud, Stéphane; Pierrot-Deseilligny, Marc

    2014-05-01

    Thermal infrared data obtained in the [7-14 microns] spectral range are usually used in many Earth Science disciplines. These studies are exclusively based on the analysis of 2D information. In this case, a quantitative analysis of the surface energy budget remains limited, as it may be difficult to estimate the radiative contribution of the topography, the thermal influence of winds on the surface or potential imprints of subsurface flows on the soil without any precise DEM. The draping of a thermal image on a recent DEM is a common method to obtain a 3D thermal map of a surface. However, this method has many disadvantages i) errors can be significant in the orientation process of the thermal images, due to the lack of tie points between the images and the DEM; ii) the use of a recent DEM implies the use of another remote sensing technique to quantify the topography; iii) finally, the characterization of the evolution of a surface requires the simultaneous acquisition of thermal data and topographic information, which may be expensive in most cases. The stereophotogrammetry method allows to reconstitute the relief of an object from photos taken from different positions. Recently, substantial progress have been realized in the generation of high spatial resolution topographic surfaces using stereophotogrammetry. However, the presence of shadows, homogeneous textures and/or weak contrasts in the visible spectrum (e.g., flowing lavas, uniform lithologies) may prevent from the use of such method, because of the difficulties to find tie points on each image. Such situations are more favorable in the thermal infrared spectrum, as any variation in the thermal properties or geometric orientation of the surfaces may induce temperature contrasts that are detectable with a thermal camera. This system, usually functioning with a array sensor (Focal Plane Array) and an optical device, have geometric characteristics that are similar to digital cameras. Thus, it may be possible

  17. A 3D incompressible thermal lattice Boltzmann model and its application to simulate natural convection in a cubic cavity

    A 3D incompressible thermal lattice Boltzmann model is proposed in this paper to solve 3D incompressible thermal flow problems. Two different particle velocity models of D3Q15 and D3Q19 are incorporated in our thermal model. It is indicated that the present thermal model is simple and easy for implementation. It is validated by its application to simulate the 3D natural convection of air in a cubical enclosure, which is heated differentially at two vertical side walls. Good agreement was obtained between the present results and those from a Navier-Stokes solver

  18. Validation and verification of the coupled neutron kinetic/thermal hydraulic system code DYN3D/ATHLET

    Highlights: • General description of the coupled code DYN3D/ATHLET developed in HZDR (Helmholtz-Zentrum Dresden-Rossendorf) and used to simulate steady-state and transient behaviour of LWRs is given. • Nearly 20 real plant transients and dynamic benchmarks for 5 LWR designs were simulated to evaluate the coupling interface between two integrated codes and interaction of DYN3D model of 3-D neutron kinetics with plant components modelled by ATHLET. • An overview of DYN3D/ATHLET validation and verification activities is given with references to published results. • The results of two most recently performed validation (Kalinin-3) and verification (AER-7) tasks are presented in a separate chapter in more detail. • The validation/verification status of DYN3D/ATHLET was noticeably increased. - Abstract: One of the most intensively developing areas in the LWR multi-physics is a coupling of different best estimate 3-D neutron kinetic (BIPR, DYN3D, KIKO3D, NEM, PARCS, etc.) and thermal hydraulic (ATHLET, CATHARE, RELAP5, etc.) codes. Resulting coupled code systems have advanced capabilities of modeling both steady-state spatial distributions of the core power and their evolutions during different kinds of reactor transients. They are also highly useful in the analyses of possible reactor instabilities. Initial steady-state core power distributions can be disturbed by changes in the reactor loop mass flow rates and/or temperatures, by relocations of the low-temperature/diluted-boron water slugs within the primary system or by movements of control rods. The coupled code used for LWR simulations in HZDR is DYN3D/ATHLET, which includes the 3-D core neutron kinetic and thermal hydraulic model of own development – DYN3D. The paper reports major capabilities of DYN3D as well as different ways of its coupling with the thermal hydraulic code ATHLET (external, internal and parallel), but mainly focuses on the validation and verification of the coupled code DYN3D

  19. Thermal hydraulic analysis for the Oregon State TRIGA reactor using RELAP5-3D

    Thermal hydraulic analyses have being conducted at Oregon State University (OSU) in support of the conversion of the OSU TRIGA reactor (OSTR) core from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel as part of the Reduced Enrichment for Research and Test Reactors program. The goals of the thermal hydraulic analyses were to calculate natural circulation flow rates, coolant temperatures and fuel temperatures as a function of core power for both the HEU and LEU cores; calculate peak values of fuel temperature, cladding temperature, surface heat flux as well as departure from nuclear boiling ratio (DNBR) for steady state and pulse operation; and perform accident analyses for the accident scenarios identified in the OSTR safety analysis report. RELAP5-3D Version 2.4.2 was implemented to develop a model for the thermal hydraulic study. The OSTR core conversion is planned to take place in late 2008. (author)

  20. Reconstructing the Thermal Sunyaev-Zel'dovich Effect in 3D

    Pratten, Geraint

    2014-01-01

    The thermal Sunyaev-Zel'dovich (tSZ) effect is one of the most promising tools we have for probing the baryonic Universe. Unfortunately, the tSZ effect is defined as a line of sight projection of the thermal pressure fluctuations of free-electrons, compromising our ability to probe the thermal history of the Universe by smearing out the tSZ observables. This results in a loss of redshift information diminishing the power of tSZ observations. It is hoped that by cross-correlating the tSZ effect with external tracers we can recover a good fraction of the lost information. Weak lensing (WL) is thought to provide a relatively unbiased probe of the dark Universe in 3D with many upcoming WL surveys having sky coverage that overlaps with current tSZ surveys. Generalising the commonly used tomographic approach, we advocate the use of the spherical Fourier-Bessel (sFB) expansion as a means to perform a full analysis of cross-correlations between the projected (2D) tSZ Compton y-parameter maps and 3D WL-convergence kap...

  1. Thermal 3D model for Direct Solar Steam Generation under superheated conditions

    Highlights: • A new 3D model for single-phase flow in PTCs is proposed for the solid domain. • The model is based on one-dimensional heat transfer correlations. • A 3D optical model has been solved in conjunction with the thermal model. • Model results have been validated with experimental data from a real test facility. - Abstract: Parabolic-trough collectors (PTC) solar systems are one of the most promising of a wide range of the available solar technologies. Continuous breakthroughs are being achieved. Mainly due to the considerable amount of solar PTC plants that are being under operation in different countries. Within this continuous improvement effort, Direct Steam Generation (DSG) has been under development. DSG will lead to cheaper systems, not only for electricity generation but for heat process requirements. Working with superheated steam as thermal fluid, implies thicker pipe walls. Current numerical models neglect the radial dimension. In this context, simulating DSG absorbers implies considering radial domain discretization. A single phase model has been developed in order to work the 3D temperature field out on the solid parts, including the glass cover. Vacuum annulus has been assumed between stainless steel absorber and the glass envelope. The thermal radiative interaction between those parts has been considered without constant temperature assumption over the glass envelope. Finally, unidimensional approximation has been applied to the fluid domain. The whole code has been developed from the elemental (PDEs) governing equations and has been implemented in Matlab®. The numerical model has been validated from experimental results. These results have been gathered from an experimental DSG test facility with parabolic-troughs

  2. Task-specific evaluation of 3D image interpolation techniques

    Grevera, George J.; Udupa, Jayaram K.; Miki, Yukio

    1998-06-01

    Image interpolation is an important operation that is widely used in medical imaging, image processing, and computer graphics. A variety of interpolation methods are available in the literature. However, their systematic evaluation is lacking. At a previous meeting, we presented a framework for the task independent comparison of interpolation methods based on a variety of medical image data pertaining to different parts of the human body taken from different modalities. In this new work, we present an objective, task-specific framework for evaluating interpolation techniques. The task considered is how the interpolation methods influence the accuracy of quantification of the total volume of lesions in the brain of Multiple Sclerosis (MS) patients. Sixty lesion detection experiments coming from ten patient studies, two subsampling techniques and the original data, and 3 interpolation methods is presented along with a statistical analysis of the results. This work comprises a systematic framework for the task-specific comparison of interpolation methods. Specifically, the influence of three interpolation methods in MS lesion quantification is compared.

  3. Evaluation of field development plans using 3-D reservoir modelling

    Seifert, D.; Lewis, J.J.M. [Heriot-Watt Univ., Edinburgh (United Kingdom); Newbery, J.D.H. [Conoco, UK Ltd., Aberdeen (United Kingdom)] [and others

    1997-08-01

    Three-dimensional reservoir modelling has become an accepted tool in reservoir description and is used for various purposes, such as reservoir performance prediction or integration and visualisation of data. In this case study, a small Northern North Sea turbiditic reservoir was to be developed with a line drive strategy utilising a series of horizontal producer and injector pairs, oriented north-south. This development plan was to be evaluated and the expected outcome of the wells was to be assessed and risked. Detailed analyses of core, well log and analogue data has led to the development of two geological {open_quotes}end member{close_quotes} scenarios. Both scenarios have been stochastically modelled using the Sequential Indicator Simulation method. The resulting equiprobable realisations have been subjected to detailed statistical well placement optimisation techniques. Based upon bivariate statistical evaluation of more than 1000 numerical well trajectories for each of the two scenarios, it was found that the wells inclinations and lengths had a great impact on the wells success, whereas the azimuth was found to have only a minor impact. After integration of the above results, the actual well paths were redesigned to meet external drilling constraints, resulting in substantial reductions in drilling time and costs.

  4. A 3D Finite Element evaluation of the exophthalmia reduction

    Luboz, V; Boutault, F; Swider, P; Payan, Y; Luboz, Vincent; Pedrono, Annaig; Boutault, Franck; Swider, Pascal; Payan, Yohan

    2003-01-01

    This paper presents a first evaluation of the feasibility of Finite Element modelling of the orbital decompression, in the context of exophthalmia. First simulations are carried out with data extracted from a patient TDM exam. Results seem to qualitatively validate the feasibility of the simulations, with a Finite Element analysis that converges and provides a backward movement of the ocular globe associated with displacements of the fat tissues through the sinuses. This FE model can help a surgeon for the planning of the exophthalmia reduction, and especially for the position and the size of the decompression hole. To get an estimation of the fat tissues volume affected by the surgery, an analytical model seems to provide quicker results for an equivalent efficiency.

  5. Thermal-hydraulic characteristics and performance of 3D wavy channel based printed circuit heat exchanger

    CFD study is done here to propose an efficient PCHE (Printed Circuit Heat Exchanger) model; used as a recuperator in International Thermonuclear Experimental Reactor (ITER). 3D steady state conjugate heat-transfer numerical simulations are done; considering the variation of thermo-physical properties as a function of temperature. Helium is used as a working fluid and alloy 617 as solid substrate. The study is done for various angle of bend (θ = 0°(straight), 5°, 10° and 15°) and Reynolds number (Re = 350, 700, 1400 and 2100). Various types of flow patterns, within one wavy-section, are presented to analyze thermal-hydraulic characteristics. Thermal hydraulic performance parameters are presented for the various wavy-sections as well as within a section; and for the complete PCHE model. Heat transfer enhancement as compared to pressure penalty is higher for the wavy channel; and increases with increasing Re and θ. Wavy as compared to plane channel based PCHE is demonstrated here to give better thermal-hydraulic performance. A detailed characteristics as well as performance-parameters for thermal hydraulics in a 3D wavy channel based PCHE model − not found in the literature − is presented here. - Highlights: • Studied effect of Reynolds number and angle of bend. • Analyzed thermal-hydraulic characteristics, by various types of flow pat-terns. • Demonstrated an increase in local heat flux due to change in the flow-direction. • Demonstrated better performance of wavy as compared to plane channel based PCHE. • Proposed correlation for friction factor and Nusselt number

  6. Evaluation of 3-D Power Distribution Synthesis Method for SMART Core Monitoring System

    A 3-dimensional power distribution synthesis method, named DPCM3D has been developed by KAERI. SMART core monitoring system, SCOMS adopted this method instead of Fourier expansion method for the digital monitoring system of conventional PWRs. The DPCM3D method produces a synthetic 3-D power distribution by coupling a neutronics code and measured in-core detector signals. In DPCM3D, instrumented node powers are determined from the detector powers by using power sharing factors and the un-instrumented node powers are determined by using power connection factors. A coefficient library for the 3-D power synthesis is functionalized as a function of the burnup, core power and control rod position. In this paper, performance of SCOMS 3-D power distribution synthesis method for SMART initial core was evaluated

  7. The use of 3D-CT-Angiography in the diagnostic procedure of intracranial aneurysms evaluated

    Aalders, Th.; Labisch, C.; Seifert, V.; Zanella, F.E.; Stolke, D. [Univ. Clinic Essen (Germany)

    1998-11-01

    With improving quality of images obtained by 3D-CT-Angiography, this procedure may promise to become a powerful tool in intracranial aneurysm diagnostic. We have evaluated this method comparatively between angiographic and intra-operative findings. Forty-one patients were examined by cerebral angiography and 3D-Angio-CT. Radiological findings were evaluated by neuroradiologists and neurosurgeons. Intra-operative findings were documented by video or photography. All angiographically proven aneurysms were also visualized by 3D-Angio-CT. In over sixty percent of cases 3D-Angio-CT showed the aneurysmal anatomy equally well to angiography or presented valuable additional information not obtainable by angiography. In complex aneurysms as well as in aneurysms of the posterior circulation, the additional information offered by 3D-Angio-CT was most valuable. Intra-operative anatomical findings showed a high correlation with 3D-images. In our experience 3D-Angio-CT proved to be a powerful tool in the diagnostic procedure of intracranial aneurysms, either in the acute or non-acute phase. In many cases 3D-images present valuable additional information not otherwise obtainable, especially in complex aneurysms and aneurysms of the posterior circulation. In selected cases neurosurgical therapy can be planned on 3D-images alone. Nontheless conventional cerebral angiography remains the gold standard in diagnostic management of intracranial aneurysms. (author)

  8. Investigation of thermal degradation with extrusion-based dispensing modules for 3D bioprinting technology.

    Lee, Hyungseok; Yoo, James J; Kang, Hyun-Wook; Cho, Dong-Woo

    2016-03-01

    Recently, numerous three-dimensional (3D) bioprinting systems have been introduced for the artificial regeneration of tissues. Among them, the extrusion-based dispensing module is the most widely used because of the processability it gives various biomaterials. The module uses high forces and temperature to dispense materials through a micro-nozzle. Generally, the harsh conditions induce thermal degradation of the material in the dispensing procedure. The thermal degradation affects the properties of the materials, and the change of the properties should be carefully controlled, because it severely affects the regeneration of tissues. Therefore, in this research, the relationship between the dispensing module and the thermal degradation of material was investigated. Extrusion-based dispensing modules can be divided into the syringe type (ST) and filament type (FT) based on working principles. We prepared a poly lactic-co-glycolic acid (PLGA) scaffold with the two methods at various time points. Then, the characteristics of the printed scaffolds were assessed by measuring molecular weight (M w), glass transition temperature (T g), in vitro degradation, compressive modulus, and cytocompatibility. The results showed that the PLGA scaffold with the FT dispensing module maintained its properties regardless of printing time points. In contrast, severe thermal degradation was observed in the scaffold group prepared by the ST dispensing module. Consequentially, it was obvious that the FT dispensing module was more suitable for producing scaffolds without severe thermal degradation. PMID:26844711

  9. Sodium Experiments on Natural Circulation Decay Heat Removal and 3D Simulation of Plenum Thermal Hydraulics

    Natural circulation decay heat removal is one of the significant issues for fast reactor safety, especially in long term station blackout events. Several sodium experiments were carried out using a 7-subassembly core model for core thermal hydraulics under natural circulation conditions and for onset transients of natural circulation in a decay heat removal system (DHRS) including natural draft. Significant heat removal via inter-wrapper flow was confirmed in the experiments. Solidification of sodium in an air cooler is one of key issues in loss of heat sink events. Natural circulation characteristics under long-term decay heat removal were also obtained. Multi-dimensional phenomena, e.g., thermal stratification and bypass flow in plenums and/or heat exchangers, may influence the natural circulation. Thus, 3D simulation method was developed for entire region in the primary loop. Comparison of temperature distributions in a DHRS heat exchanger between experiment and analysis was done. (author)

  10. Reconstructing the thermal Sunyaev-Zel'dovich effect in 3D

    Pratten, Geraint; Munshi, Dipak

    2014-07-01

    The thermal Sunyaev-Zel'dovich (tSZ) effect measures the line-of-sight projection of the thermal pressure of free electrons and lacks any redshift information. By cross-correlating the tSZ effect with an external cosmological tracer, we can recover a good fraction of this lost information. Weak lensing (WL) is thought to provide an unbiased probe of the dark Universe, with many WL surveys having sky coverage that overlaps with tSZ surveys. Generalizing the tomographic approach, we advocate the use of the spherical Fourier-Bessel expansion to perform an analysis of the cross-correlation between the projected (2D) tSZ Compton y-parameter maps and 3D WL convergence maps. We use redshift-dependent linear biasing and the halo model as a tool to investigate the tSZ-WL cross-correlations in 3D. We use the Press-Schechter and the Sheth-Tormen mass functions in our calculations, finding that the results are quite sensitive to detailed modelling. We provide detailed analysis of surveys with photometric and spectroscopic redshifts. The signal-to-noise ratio (S/N) of the cross-spectra {C}_{ℓ} (k) for individual 3D modes, defined by the radial and tangential wave numbers (k; ℓ), remains comparable to, but below, unity though optimal binning is expected to improve this. The results presented can be generalized to analyse other cosmic microwave background secondaries, such as the kinetic Sunyaev-Zel'dovich effect.

  11. Modeling and simulation of 3D thermal stresses of large-sized castings in solidification processes

    2004-01-01

    When heavy machines and large scaled receiver system of communication equipment are manufactured, it always needs to produce large- sized steel castings, aluminum castings and etc. Some defects of hot cracking by thermal stress often appear during solidification process as these castings are produced, which results in failure of castings.Therefore predicting the effects of technological parameters for production of castings on the thermal stress during solidification process becomes an important means. In this paper, the mathematical models have been established and numerical calculation of temperature fields by using finite difference method (FDM) and then thermal stress fields by using finite element method (FEM) during solidification process of castings have been carried out. The technological parameters of production have been optimized by the results of calculation and the defects of hot cracking have been eliminated. Modeling and simulation of 3D thermal stress during solidification processes of large-sized castings provided a scientific basis, which promoted further development of advanced manufacturing technique.

  12. 3-D thermal and hydrodynamic modelling of elaboration of glass by induction in cold crucible

    Full text of publication follows: Vitrification in cold crucible requires a perfect control of thermal and hydrodynamic phenomena. In this process, electric currents are directly induced in the glass by the inductor surrounding the crucible. The crucible is placed on a base fitted with a cooled pouring valve. The advantages of the cold crucible are mainly due to the formation of a thin layer that solidifies upon contact with the cold melter walls. To understand the phenomena concerning vitrification, modelling has been considered. The main difficulties of modelling come from the coupling between the electromagnetic, hydraulic and thermal aspects that are complex because of two points. Firstly, the modelling is complicated by the asymmetry created by the stirring systems used to homogenize the molten glass bath. Secondly, the complexity of the problems comes from the important thermal variations of the physical properties of the glass. Near the wall where glass is solidified, the dynamic viscosity reaches 7000 Pa.s. and glass is an insulating material, but once melted the electrical resistivity drops to 10 Ω.cm, allowing electric currents and the viscosity of glass becomes below 10 Pa.s.. This paper presents the successive steps of the modelling of the cold crucible. The first step consists of checking the possibilities of the code with 2D-axisymmetric modelling, after that 3D-modelling is treated. For both cases, the stirrer is not taken into account; the molten glass is driven by the buoyancy forces. The coupling between the three phenomena (electromagnetic, hydraulic and thermal) is a low coupling; the distribution of the Joule power is calculated with another code and directly injected in the calculation without return. The validations are achieved with thermal experimental results obtained on vitrification pilot facility installed at CEA/Valrho-Marcoule. A comparison between 2-D and 3-D results is presented. Finally a strong coupling is considered and the flow

  13. 3D neutronic codes coupled with thermal-hydraulic system codes for PWR, and BWR and VVER reactors

    Langenbuch, S.; Velkov, K. [GRS, Garching (Germany); Lizorkin, M. [Kurchatov-Institute, Moscow (Russian Federation)] [and others

    1997-07-01

    This paper describes the objectives of code development for coupling 3D neutronics codes with thermal-hydraulic system codes. The present status of coupling ATHLET with three 3D neutronics codes for VVER- and LWR-reactors is presented. After describing the basic features of the 3D neutronic codes BIPR-8 from Kurchatov-Institute, DYN3D from Research Center Rossendorf and QUABOX/CUBBOX from GRS, first applications of coupled codes for different transient and accident scenarios are presented. The need of further investigations is discussed.

  14. 3D perfused brain phantom for interstitial ultrasound thermal therapy and imaging: design, construction and characterization

    Thermal therapy has emerged as an independent modality of treating some tumors. In many clinics the hyperthermia, one of the thermal therapy modalities, has been used adjuvant to radio- or chemotherapy to substantially improve the clinical treatment outcomes. In this work, a methodology for building a realistic brain phantom for interstitial ultrasound low dose-rate thermal therapy of the brain is proposed. A 3D brain phantom made of the tissue mimicking material (TMM) had the acoustic and thermal properties in the 20–32 °C range, which is similar to that of a brain at 37 °C. The phantom had 10–11% by mass of bovine gelatin powder dissolved in ethylene glycol. The TMM sonicated at 1 MHz, 1.6 MHz and 2.5 MHz yielded the amplitude attenuation coefficients of 62  ±  1 dB m−1, 115  ±  4 dB m−1 and 175  ±  9 dB m−1, respectively. The density and acoustic speed determination at room temperature (∼24 °C) gave 1040  ±  40 kg m−3 and 1545  ±  44 m s−1, respectively. The average thermal conductivity was 0.532 W m−1 K−1. The T1 and T2 values of the TMM were 207  ±  4 and 36.2  ±  0.4 ms, respectively. We envisage the use of our phantom for treatment planning and for quality assurance in MRI based temperature determination. Our phantom preparation methodology may be readily extended to other thermal therapy technologies. (paper)

  15. Evaluation of isocenter reproducibility in telemedicine of 3D-radiotherapy treatment planning

    Hirota, Saeko; Tsujino, Kayoko; Kimura, Kouji; Takada, Yoshiki; Hishikawa, Yoshio; Kono, Michio [Hyogo Medical Center for Adults, Akashi (Japan); Soejima, Toshinori; Kodama, Akihisa

    2000-09-01

    To evaluate the utility in telemedicine of Three-Dimensional Radiotherapy Treatment Planning (tele-3D-RTP) and to examine the accuracy of isocenter reproducibility in its offline trial. CT data of phantoms and patients in the satellite hospital were transferred to our hospital via floppy-disk and 3D-radiotherapy plans were generated by 3D-RTP computer in our hospital. Profile data of CT and treatment beams in the satellite hospital were pre-installed into the computer. Tele-3D-RTPs were performed in 3 phantom plans and 14 clinical plans for 13 patients. Planned isocenters were well reproduced, especially in the immobilized head and neck/brain tumor cases, whose 3D-vector of aberration was 1.96{+-}1.38 (SD) mm. This teletherapy system is well applicable for practical use and can provides cost-reduction through sharing the resources of expensive equipment and radiation oncologists. (author)

  16. Evaluation of a new method for stenosis quantification from 3D x-ray angiography images

    Betting, Fabienne; Moris, Gilles; Knoplioch, Jerome; Trousset, Yves L.; Sureda, Francisco; Launay, Laurent

    2001-05-01

    A new method for stenosis quantification from 3D X-ray angiography images has been evaluated on both phantom and clinical data. On phantoms, for the parts larger or equal to 3 mm, the standard deviation of the measurement error has always found to be less or equal to 0.4 mm, and the maximum measurement error less than 0.17 mm. No clear relationship has been observed between the performances of the quantification method and the acquisition FoV. On clinical data, the 3D quantification method proved to be more robust to vessel bifurcations than its 3D equivalent. On a total of 15 clinical cases, the differences between 2D and 3D quantification were always less than 0.7 mm. The conclusion is that stenosis quantification from 3D X-4ay angiography images is an attractive alternative to quantification from 2D X-ray images.

  17. Evaluation of isocenter reproducibility in telemedicine of 3D-radiotherapy treatment planning

    To evaluate the utility in telemedicine of Three-Dimensional Radiotherapy Treatment Planning (tele-3D-RTP) and to examine the accuracy of isocenter reproducibility in its offline trial. CT data of phantoms and patients in the satellite hospital were transferred to our hospital via floppy-disk and 3D-radiotherapy plans were generated by 3D-RTP computer in our hospital. Profile data of CT and treatment beams in the satellite hospital were pre-installed into the computer. Tele-3D-RTPs were performed in 3 phantom plans and 14 clinical plans for 13 patients. Planned isocenters were well reproduced, especially in the immobilized head and neck/brain tumor cases, whose 3D-vector of aberration was 1.96±1.38 (SD) mm. This teletherapy system is well applicable for practical use and can provides cost-reduction through sharing the resources of expensive equipment and radiation oncologists. (author)

  18. Development and evaluation of a semiautomatic 3D segmentation technique of the carotid arteries from 3D ultrasound images

    Gill, Jeremy D.; Ladak, Hanif M.; Steinman, David A.; Fenster, Aaron

    1999-05-01

    In this paper, we report on a semi-automatic approach to segmentation of carotid arteries from 3D ultrasound (US) images. Our method uses a deformable model which first is rapidly inflated to approximately find the boundary of the artery, then is further deformed using image-based forces to better localize the boundary. An operator is required to initialize the model by selecting a position in the 3D US image, which is within the carotid vessel. Since the choice of position is user-defined, and therefore arbitrary, there is an inherent variability in the position and shape of the final segmented boundary. We have assessed the performance of our segmentation method by examining the local variability in boundary shape as the initial selected position is varied in a freehand 3D US image of a human carotid bifurcation. Our results indicate that high variability in boundary position occurs in regions where either the segmented boundary is highly curved, or the 3D US image has poorly defined vessel edges.

  19. Engineering EMT using 3D micro-scaffold to promote hepatic functions for drug hepatotoxicity evaluation.

    Wang, Jingyu; Chen, Fengling; Liu, Longwei; Qi, Chunxiao; Wang, Bingjie; Yan, Xiaojun; Huang, Chenyu; Hou, Wei; Zhang, Michael Q; Chen, Yang; Du, Yanan

    2016-06-01

    Accompanied by decreased hepatic functions, epithelial-mesenchymal transition (EMT) was observed in two dimensional (2D) cultured hepatocytes with elongated morphology, loss of polarity and weakened cell-cell interaction, while upgrading to 3D culture has been considered as significant improvement of its 2D counterpart for hepatocyte maintenance. Here we hypothesize that 3D culture enhances hepatic functions through regulating the EMT status. Biomaterial-engineered EMT was achieved by culturing HepaRG as 3D spheroids (SP-3D) or 3D stretched cells (ST-3D) in non-adherent and adherent micro-scaffold respectively. In SP-3D, constrained EMT of HepaRG, a hepatic stem cell line, as represented by increased epithelial markers and decreased mesenchymal markers, was echoed by improved hepatic functions. To investigate the relationship between EMT status and hepatic functions, time-series RNA-Seq and gene network analysis were used for comparing different cell culture models, which identified histone deacetylases (HDACs) as key mediating factors. Protein analysis confirmed that high HDAC activity was correlated with high expression of Cadherin-1 (CDH1) and hepatic function genes, which were decreased upon HDAC inhibitor treatment in SP-3D, suggesting HDACs may play positive role in regulating EMT and hepatic functions. To illustrate the application of 3D micro-scaffold culture in drug safety evaluation, hepatotoxicity and metabolism assays of two hepatotoxins (i.e. N-acetyl-p-aminophenol and Doxorubicin) were performed and SP-3D showed more biomimetic toxicity response, indicating regulation of EMT as a vital consideration in designing 3D hepatocyte culture configuration. PMID:26994875

  20. On Fundamental Evaluation Using Uav Imagery and 3d Modeling Software

    Nakano, K.; Suzuki, H.; Tamino, T.; Chikatsu, H.

    2016-06-01

    Unmanned aerial vehicles (UAVs), which have been widely used in recent years, can acquire high-resolution images with resolutions in millimeters; such images cannot be acquired with manned aircrafts. Moreover, it has become possible to obtain a surface reconstruction of a realistic 3D model using high-overlap images and 3D modeling software such as Context capture, Pix4Dmapper, Photoscan based on computer vision technology such as structure from motion and multi-view stereo. 3D modeling software has many applications. However, most of them seem to not have obtained appropriate accuracy control in accordance with the knowledge of photogrammetry and/or computer vision. Therefore, we performed flight tests in a test field using an UAV equipped with a gimbal stabilizer and consumer grade digital camera. Our UAV is a hexacopter and can fly according to the waypoints for autonomous flight and can record flight logs. We acquired images from different altitudes such as 10 m, 20 m, and 30 m. We obtained 3D reconstruction results of orthoimages, point clouds, and textured TIN models for accuracy evaluation in some cases with different image scale conditions using 3D modeling software. Moreover, the accuracy aspect was evaluated for different units of input image—course unit and flight unit. This paper describes the fundamental accuracy evaluation for 3D modeling using UAV imagery and 3D modeling software from the viewpoint of close-range photogrammetry.

  1. 3D coexisting modes of thermal convection in the faulted Lower Yarmouk Gorge

    Magri, Fabien; Inbar, Nimrod; Möller, Peter; Raggad, Marwan; Rödiger, Tino; Rosenthal, Eliyahu; Siebert, Christian

    2016-04-01

    Numerical investigations of 3D modes of large-scale convection in faulted aquifers are presented with the aim to infer possible transport mechanisms supporting the formation of thermal springs in the Lower Yarmouk Gorge (LYG), at the border between Israel and Jordan. The transient finite elements models are based on a geological model of the LYG that introduces more realistic structural features of the basin, compared to previous existing models of the area (Magri et al., submitted). The sensitivity analysis of the fault permeability showed that faults cross-cutting the main regional flow direction allow groundwater to be driven laterally by convective forces within the fault planes. Therein thermal waters can either discharge along the fault traces or exit the fault through adjacent permeable aquifers. The location of springs can migrate with time, is not strictly constrained to the damage zones and reflects the interplay between the wavelength of the multicellular regime in the fault zone and the regional flow toward discharge areas in the lowlands. The results presented here suggest that in the LYG case, crossing flow paths result from the coexistence of fault convection, that can develop for example along NE-SW oriented faults within the Gorge, and additional flow fields that can be induced either by topography N-S gradients, e.g. perpendicular to the major axe of the Gorge, or by local thermal convection in permeable aquifers below Eocene aquiclude. The sensitivity analysis is consistent with the analytical solutions based on viscous-dependent Rayleigh theory. It indicates that in the LYG coexisting transport processes likely occur at fault hydraulic conductivity ranging between 2.3e-7 m/s and 9.3e- 7 m/s (i.e. 7 m/yr and 30 m/yr). The LYG numerical example and the associated Rayleigh analysis can be applied to study the onset of thermal convection and resulting flow patterns of any fractured hydrothermal basin. References Magri F, Möller S, Inbar N, M

  2. A corrected vortex blob method for 3D thermal buoyant flows

    Golia, Carmine; Buonomo, Bernardo; Viviani, Antonio [Seconda Universita di Napoli (SUN), Dipartimento di Ingegneria Aerospaziale e Meccanica (DIAM), via Roma 29, 81031 Aversa (Italy)

    2008-11-15

    This work explores novel ideas to improve the accuracy of integral approximation to differential operators (divergence, gradient and Laplacian) in the simulation of 3D thermal buoyant flows with meshless Lagrangian Blobs methods. Basically, we investigate and develop an integral discretization of the differential operators of the field equations, by using convolutions of truncated 3D-Taylor series expansions with a kernel function defined on a compact support around the blob centre of a given particle. This allows to overtake: circle the irregular distribution of cells in the compact support around the given blob, circle the deficiency of cells in the compact support due to the presence of a boundary cutting the compact support of nearby blobs. The accuracy and the order of approximation of such discretizations are determined in regular and randomly distorted grids of various sizes, and compared with the widely used particle strength exchange formulations. The analysis of the effects of using the new formulations to solve problems at realistic values of the Grashof number demonstrates the validity and the benefits of the novel findings. (author)

  3. 3-D Thermal, Hydrodynamic and Magnetic Modelling of Elaboration of Glass by Induction in Cold Crucible

    The Vitrification of high-level liquid waste produced from nuclear fuel reprocessing has been carried out industrially for more than 30 years by AREVA, with three main objectives: containment of the long lived fission products, reduction of the final volume of waste and operability in an industrial context. In parallel the French Atomic Energy Commission (CEA), SGN (respectively Areva's R and D provider and Engineering) and AREVA (industrial Operator) have developed the cold crucible induction melter vitrification technology to obtain greater operating flexibility, increased plant availability and further reduction of secondary waste generated during operations. The 3D numerical simulation of elaboration of glass by induction in cold crucible needs a coupled approach of the different phenomena: induction, thermal and hydrodynamic. Indeed, those three phenomena are strongly coupled because of the temperature dependence of the glass properties. The hotter the molten glass, the higher the electrical conductivity. In the present paper, we will focus on a full 3D simulation, when mechanical stirrer and bubbling are stopped in the cold crucible melter. In this case, the convection is driven by two phenomena. First, buoyancy forces are modelled in the Boussinesq approximation. Second, thermo capillary convection at the surface is taken into account. This effect is due to the variation of the surface tension with the temperature. Thermo convective circulations appear within the molten glass when the total Joule power injected reached a specific threshold. (authors)

  4. Development of the safety analysis method based on the 3-D core kinetics coupled with thermal-hydraulics code

    In the present Non-LOCA safety analysis of the Pressurized Water Reactor (PWR), plant transient, core response and fuel behavior are independently calculated by different analysis codes to estimate the plant safety. Therefore these results often involve large un-quantified conservativeness due to additional safety margins for initial/boundary conditions of each calculation and simplistic approximations for complicated interactions between the core neutronics and plant thermal-hydraulics during the transient. Recently, best estimate 3-D core transient analysis codes have been widely developed in the area of nuclear reactor accident analysis to understand actual physical phenomena and quantification of conservativeness in the current safety analysis. Evaluating safety margins appropriately contributes to the more safety of the plant design and the efficiency of the plant operation. Mitsubishi Heavy Industries (MHI) has developed the 3-D core kinetics coupled with the thermal-hydraulics code SPARKLE, and has a plan to apply it for the commercial licensing in the near future. This paper presents the feature of the SPARKLE code and the results of the application to representative accident events. (author)

  5. Millimeter radiation from a 3D model of the solar atmosphere I. Diagnosing chromospheric thermal structure

    Loukitcheva, Maria; Carlsson, Mats; White, Stephen

    2015-01-01

    Aims. We use advanced 3D NLTE radiative magnetohydrodynamic simulations of the solar atmosphere to carry out detailed tests of chromospheric diagnostics at millimeter and submillimeter wavelengths. Methods. We focused on the diagnostics of the thermal structure of the chromosphere in the wavelength bands from 0.4 mm up to 9.6 mm that can be accessed with the Atacama Large Millimeter/Submillimeter Array (ALMA) and investigated how these diagnostics are affected by the instrumental resolution. Results. We find that the formation height range of the millimeter radiation depends on the location in the simulation domain and is related to the underlying magnetic structure. Nonetheless, the brightness temperature is a reasonable measure of the gas temperature at the effective formation height at a given location on the solar surface. There is considerable scatter in this relationship, but this is significantly reduced when very weak magnetic fields are avoided. Our results indicate that although instrumental smearin...

  6. STAR 3D nodal kinetics and thermal-hydraulic model for the Pennsylvania State TRIGA reactor

    A detailed three-dimensional (3D) time-dependent STAR nodal kinetics model coupled to a one-dimensional (1 D) thermal-hydraulics WIGL model has been developed to describe conservatively the peak power and pulse behavior of the Penn State University (PSU) Breazeale TRIGA reactor. This paper describes how the STAR model and its cross section data input was developed and benchmarked against actual TRIGA pulse experiments. Different core configurations (i.e., different core loading patterns, and with/without the TRIGA core next to the D20 tank) were used for several TRIGA pulse tests with different reactivity insertion worths (1.5$, 2.0$ , 2.5$). This paper shows that the STAR nodal kinetics code adequately simulates TRIGA pulses when group constants are generated from physics codes (i.e., WIMS-D4) that can accurately model the TRIGA uranium-zirconium-hydride fuel. (author)

  7. First impressions of 3D visual tools and dose volume histograms for plan evaluation

    Converting from 2D to 3D treatment planning offers numerous challenges. The practices that have evolved in the 2D environment may not be applicable when translated into the 3D environment. One such practice is the methods used to evaluate a plan. In 2D planning a plane by plane comparison method is generally practiced. This type of evaluation method would not be appropriate for plans produced by a 3D planning system. To this end 3D dose displays and Dose Volume Histograms (DVHs) have been developed to facilitate the evaluation of such plans. A survey was conducted to determine the impressions of Radiation Therapists as they used these tools for the first time. The survey involved comparing a number of plans for a small group of patients and selecting the best plan for each patient. Three evaluation methods were assessed. These included the traditional plane by plane, 3D dose display, and DVHs. Those surveyed found the DVH to be the easiest of the three methods to use, with the 3D display being the next easiest. Copyright (1999) Blackwell Science Pty Ltd

  8. On the evaluation of photogrammetric methods for dense 3D surface reconstruction in a metrological context

    I. Toschi; Capra, A.; De Luca, L; Beraldin, J.-A.; Cournoyer, L.

    2014-01-01

    This paper discusses a methodology to evaluate the accuracy of recently developed image-based 3D modelling techniques. So far, the emergence of these novel methods has not been supported by the definition of an internationally recognized standard which is fundamental for user confidence and market growth. In order to provide an element of reflection and solution to the different communities involved in 3D imaging, a promising approach is presented in this paper for the assessment of ...

  9. 3D-FE-calculations of a pressure vessel under thermal shock loading

    The initiation and the stable crack growth during a thermal shock in ducts A2 and the cylindrical wall of a pressure vessel are estimated. Various finite element program packages (IWM, GRS: ADINAT, ADINA: MPA: Smart, Permas, ADINA) with extensions for fracture mechanics evaluations are used for this, in order to determine the temperature fields depending on time, stress distributions and the J integral values due to thermal shock in the 3 dimensional geometry configuration. (orig./DG)

  10. Network level pavement evaluation with 1 mm 3D survey system

    Kelvin C.P. Wang

    2015-12-01

    Full Text Available The latest iteration of PaveVision3D Ultra can obtain true 1 mm resolution 3D data at full-lane coverage in all 3 directions at highway speed up to 60 mph. This paper introduces the PaveVision3D Ultra technology for rapid network level pavement survey on approximately 1280 center miles of Oklahoma interstate highways. With sophisticated automated distress analyzer (ADA software interface, the collected 1 mm 3D data provide Oklahoma Department of Transportation (ODOT with comprehensive solutions for automated evaluation of pavement surface including longitudinal profile for roughness, transverse profile for rutting, predicted hydroplaning speed for safety analysis, and cracking and various surface defects for distresses. The pruned exact linear time (PELT method, an optimal partitioning algorithm, is implemented to identify change points and dynamically determine homogeneous segments so as to assist ODOT effectively using the available 1 mm 3D pavement surface condition data for decision-making. The application of 1 mm 3D laser imaging technology for network survey is unprecedented. This innovative technology allows highway agencies to access its options in using the 1 mm 3D system for its design and management purposes, particularly to meet the data needs for pavement management system (PMS, pavement ME design and highway performance monitoring system (HPMS.

  11. 3D numerical model of the Omega Nebula (M17): simulated thermal X-ray emission

    Reyes-Iturbide, J; Rosado, M; Rodríguez-Gónzalez, A; González, R F; Esquivel, A

    2009-01-01

    We present 3D hydrodynamical simulations of the superbubble M17, also known as the Omega nebula, carried out with the adaptive grid code yguazu'-a, which includes radiative cooling. The superbubble is modelled considering the winds of 11 individual stars from the open cluster inside the nebula (NGC 6618), for which there are estimates of the mass loss rates and terminal velocities based on their spectral types. These stars are located inside a dense interstellar medium, and they are bounded by two dense molecular clouds. We carried out three numerical models of this scenario, considering different line of sight positions of the stars (the position in the plane of the sky is known, thus fixed). Synthetic thermal X-ray emission maps are calculated from the numerical models and compared with ROSAT observations of this astrophysical object. Our models reproduce successfully both the observed X-ray morphology and the total X-ray luminosity, without taking into account thermal conduction effects.

  12. Closed-loop high-speed 3D thermal probe nanolithography

    Knoll, A. W.; Zientek, M.; Cheong, L. L.; Rawlings, C.; Paul, P.; Holzner, F.; Hedrick, J. L.; Coady, D. J.; Allen, R.; Dürig, U.

    2014-03-01

    Thermal Scanning Probe Lithography (tSPL) is an AFM based patterning technique, which uses heated tips to locally evaporate organic resists such as molecular glasses [1] or thermally sensitive polymers.[2][3] Organic resists offer the versatility of the lithography process known from the CMOS environment and simultaneously ensure a highly stable and low wear tip-sample contact due to the soft nature of the resists. Patterning quality is excellent up to a resolution of sub 15 nm,[1] at linear speeds of up to 20 mm/s and pixel rates of up to 500 kHz.[4] The patterning depth is proportional to the applied force which allows for the creation of 3-D profiles in a single patterning run.[2] In addition, non-destructive imaging can be done at pixel rates of more than 500 kHz.[4] If the thermal stimulus for writing the pattern is switched off the same tip can be used to record the written topography with Angstrom depth resolution. We utilize this unique feature of SPL to implement an efficient control system for reliable patterning at high speed and high resolution. We combine the writing and imaging process in a single raster scan of the surface. In this closed loop lithography (CLL) approach, we use the acquired data to optimize the writing parameters on the fly. Excellent control is in particular important for an accurate reproduction of complex 3D patterns. These novel patterning capabilities are equally important for a high quality transfer of two-dimensional patterns into the underlying substrate. We utilize an only 3-4 nm thick SiOx hardmask to amplify the 8±0.5 nm deep patterns created by tSPL into a 50 nm thick transfer polymer. The structures in the transfer polymer can be used to create metallic lines by a lift-off process or to further process the pattern into the substrate. Here we demonstrate the fabrication of 27 nm wide lines and trenches 60 nm deep into the Silicon substrate.[5] In addition, the combined read and write approach ensures that the lateral

  13. Role of 3D MRI with proset technique in the evaluation of lumbar radiculopathy.

    Grasso, D; Borreggine, C; Melchionda, D; Bristogiannis, C; Stoppino, L P; Macarini, L

    2013-01-01

    The aim of this study is to demonstrate the effectiveness of 3-Dimensional Magnetic Resonance Imaging (3D MRI) using the ProSet technique in the diagnosis of lumbar radiculopathy and to compare morphological findings with clinical and neurophysiological data. 40 patients suffering from L5 or S1 mono-radiculopathy caused by a disc herniation were evaluated through preliminary clinical assessment and electromyography (EMG) technique. Both conventional spin-echo sequences and 3D coronal FFE with selective water excitation (ProSet imaging) were acquired. Indentation, swelling and tilt angle of the nerve root were assessed by means of a 3D MR radiculography. 3D ProSet multiplanar reconstructions (MPR) were used for quantitative measurements of L5 and S1 nerve root widths. Widths of the symptomatic nerve root were compared with those of the contralateral nerve. Data were processed using Epi Info 3.3 software (CDC, Atlanta, GA, USA) and were compared through a paired t-Student test. We observed an abnormal tilt angle in 22 patients (57,2 percent, P less than 0.05). Morphologic alterations such as monolateral swelling or indentation of the involved roots were found in 36 patients (90 percent, P less than0.01) using 3D MR radiculography. In 10 patients, EMG revealed more nerve roots involved, while 3D FFE with ProSet technique shows a single root involved. In 2 patients, alterations were demonstrated only through EMG technique. We suggest that 3D MR radiculography can provide more information than other techniques about symptomatic disc herniation, supporting the detection of morphological changes of all nerve segments. 3D FFE with ProSet technique demonstrates high sensibility to exactly identify the level of the root involved and can provide an extremely useful tool to lead a surgical planning. PMID:24152846

  14. 3D thermal analysis of a permanent magnet motor with cooling fans

    Zheng TAN; Xue-guan SONG; Bing JI; Zheng LIU; Ji-en MA; Wen-ping CAO

    2015-01-01

    Overheating of permanent magnet (PM) machines has become a major technical challenge as it gives rise to magnet demagnetization, degradation of insulation materials, and loss of motor efficiency. This paper proposes a state-of-the-art cooling system for an axial flux permanent magnet (AFPM) machine with the focus on its structural optimization. A computational fluid dynamics (CFD) simulation with thermal consideration has been shown to be an efficient approach in the literature and is thus employed in this work. Meanwhile, a simplified numerical approach to the AFPM machine with complex configuration in 3D consisting of conduction, forced convection, and conjugate heat transfer is taken as a case study. Different simplification meth-ods (including configuration and working conditions) and two optimized fans for forced convection cooling are designed and installed on the AFPM machine and compared to a natural convection cooling system. The results show that the proposed ap-proach is effective for analyzing the thermal performance of a complex AFPM machine and strikes a balance between reasona-ble simplification, accuracy, and computational resource.%目的:提出一种适合永磁电机的冷却系统设计方案,降低电机本体温度。  创新点:提出一种适合永磁电机热分析的CFD仿真模型。  方法:采用计算流体动力学方法对包含冷却风扇的永磁电机进行空间三维热力学分析和优化设计。  结论:本文提出并优化后的冷却风扇可有效降低永磁电机的最高和平均温度。

  15. Revitalizing the Space Shuttle's Thermal Protection System with Reverse Engineering and 3D Vision Technology

    Wilson, Brad; Galatzer, Yishai

    2008-01-01

    The Space Shuttle is protected by a Thermal Protection System (TPS) made of tens of thousands of individually shaped heat protection tile. With every flight, tiles are damaged on take-off and return to earth. After each mission, the heat tiles must be fixed or replaced depending on the level of damage. As part of the return to flight mission, the TPS requirements are more stringent, leading to a significant increase in heat tile replacements. The replacement operation requires scanning tile cavities, and in some cases the actual tiles. The 3D scan data is used to reverse engineer each tile into a precise CAD model, which in turn, is exported to a CAM system for the manufacture of the heat protection tile. Scanning is performed while other activities are going on in the shuttle processing facility. Many technicians work simultaneously on the space shuttle structure, which results in structural movements and vibrations. This paper will cover a portable, ultra-fast data acquisition approach used to scan surfaces in this unstable environment.

  16. FLOW3D model for below-core thermal mixing in the Oconee pressurised water reactor

    The computational fluid dynamics code FLOW3D is being used to develop a model for calculating the mixing of cold leg flows inside the vessel of a pressurised water reactor. To assess the capabilities of the model, a simulation was made of a thermal mixing test at the Oconee-1 Nuclear Station. The test measured temperature deviations at the core inlet produced by an imposed temperature difference between cold legs. Both the tests results and the simulation showed that most of the cold leg flows arrive unmixed at the core inlet. However, the simulation was unable to reproduce the asymmetric irregularities observed in the core inlet temperature distribution, and consequently the degree of mixing was under-predicted. Various sensitivity studies were carried out on the model, but these did not reveal the source of the asymmetry. It was therefore concluded that the asymmetry source was outside the scope of the model, but the model was nevertheless able to make plausible but pessimistic estimates of mixing. (author)

  17. 3D thermal-hydraulic analysis of an ITER vacuum vessel regular Field Joint

    The ITER vacuum vessel (VV), located inside the cryostat and housing the in-vessel components, is made of 9 40° sectors, connected through splice plates to form the full torus. The regions at the interface between adjacent sectors are the so-called Field Joints (FJs). While each sector has its own cooling loop to remove the heat deposition due to nuclear heating, each FJ is separately cooled. Individual inlet/outlet pipes for the water flow are thus provided for each FJ, located in the outboard bottom segment and on the upper port frame, respectively. The coolant flow splits in two streams, inboard and outboard, passing through the borated In-Wall Shielding (IWS). In this paper we present the 3D steady state thermal-hydraulic analysis of one so-called regular FJ (RFJ), at the interface between two VV regular sectors, using the commercial CFD software ANSYS-FLUENT®. The water flow field, the pressure drop, the temperature maps and the heat transfer coefficients are computed, and the effects of considering different levels of simplification of the IWS model, as well as the influence of buoyancy (natural convection), are discussed

  18. Evaluation and assessment of the seismic responses of 3-D base-isolated structures

    Hueffmann, G.K.; Sutton, W.T. [GERB Vibration Control Systems, Inc., Westmont, IL (United States)

    1995-12-01

    The 1994 Northridge earthquake offered the opportunity to evaluate and assess the seismic response of several base-isolated buildings. Assessment of 2-D base isolation is straightforward comparing separately the uncoupled horizontal and vertical building motions to the corresponding ground motions. With 3-D systems characterized by low vertical natural frequencies, the system assessment must include rocking of the structure. Neglecting this consideration leads to an erroneous conclusion that the system greatly amplifies vertical ground accelerations. The paper evaluates the seismic response of a 3-D base-isolated building as compared to the same structure on a 2-D system. The paper also shows that the vertical accelerations measured at extreme locations in the building on a 3-D base-isolation system develop mainly from rocking responses to the horizontal ground motion.

  19. A neural network based 3D/3D image registration quality evaluator for the head-and-neck patient setup in the absence of a ground truth

    Purpose: To develop a neural network based registration quality evaluator (RQE) that can identify unsuccessful 3D/3D image registrations for the head-and-neck patient setup in radiotherapy. Methods: A two-layer feed-forward neural network was used as a RQE to classify 3D/3D rigid registration solutions as successful or unsuccessful based on the features of the similarity surface near the point-of-solution. The supervised training and test data sets were generated by rigidly registering daily cone-beam CTs to the treatment planning fan-beam CTs of six patients with head-and-neck tumors. Two different similarity metrics (mutual information and mean-squared intensity difference) and two different types of image content (entire image versus bony landmarks) were used. The best solution for each registration pair was selected from 50 optimizing attempts that differed only by the initial transformation parameters. The distance from each individual solution to the best solution in the normalized parametrical space was compared to a user-defined error threshold to determine whether that solution was successful or not. The supervised training was then used to train the RQE. The performance of the RQE was evaluated using the test data set that consisted of registration results that were not used in training. Results: The RQE constructed using the mutual information had very good performance when tested using the test data sets, yielding the sensitivity, the specificity, the positive predictive value, and the negative predictive value in the ranges of 0.960-1.000, 0.993-1.000, 0.983-1.000, and 0.909-1.000, respectively. Adding a RQE into a conventional 3D/3D image registration system incurs only about 10%-20% increase of the overall processing time. Conclusions: The authors' patient study has demonstrated very good performance of the proposed RQE when used with the mutual information in identifying unsuccessful 3D/3D registrations for daily patient setup. The classifier had

  20. Interface requirements to couple thermal-hydraulic codes to 3D neutronic codes

    Langenbuch, S.; Austregesilo, H.; Velkov, K. [GRS, Garching (Germany)] [and others

    1997-07-01

    The present situation of thermalhydraulics codes and 3D neutronics codes is briefly described and general considerations for coupling of these codes are discussed. Two different basic approaches of coupling are identified and their relative advantages and disadvantages are discussed. The implementation of the coupling for 3D neutronics codes in the system ATHLET is presented. Meanwhile, this interface is used for coupling three different 3D neutronics codes.

  1. Role of 3-D Conventional Angiography In Evaluation of Intra Carnial Aneurysms

    Ahmed M Bassiouny*, Maher M Arafa*, Sameh M Abdelwahab*,

    2013-04-01

    Full Text Available Introduction: intracranial aneurysms are pathological enlargement of the brain arteries that are most commonly located in the circle of Willis. Intracranial aneurysms are relatively common with a prevalence of approximately 4%. The real danger of aneurysms is subarachnoid hemorrhage. 3D digital subtraction angiography has become a critical imaging tool in neuroradiology allowing for the visualization of detailed cerebral vasculature prior to any intervention. Aim of the work: The aim of this work is to evaluate the diagnostic performance of 3D conventional angiography in the evaluation of intracranial aneurysms compared with the conventional cerebral angiography. Methods: The studied group included 20 patients (5 men and 15 women with subarachnoid hemorrhage or known to have cerebral aneurysms. All patients were subjected to conventional cerebral angiography and 3D cerebral angiography, using C-arm (Toshiba rotational technique.Results: 3D digital subtraction angiography is superior to conventional digital subtraction angiography in 100% of the cases 3D imaging revealed the proper aneurysmal shape, size, precise assessment of its neck and relation to the surrounding vessels. Conclusion: Three-dimensional DSA improves the detection and delineation of intracranial aneurysms

  2. Implementation and evaluation of a 3D one-step late reconstruction algorithm for 3D positron emission tomography brain studies using median root prior

    A fully three-dimensional (3D) one-step late (OSL), maximum a posteriori (MAP) reconstruction algorithm based on the median root prior (MRP) was implemented and evaluated for the reconstruction of 3D positron emission tomography (PET) studies. The algorithm uses the ordered subsets (OS) scheme for convergence acceleration and data update during iterations. The algorithm was implemented using the software package developed within the EU project PARAPET (www.brunel.ac.uk/ masrppet). The MRP algorithm was evaluated using experimental phantom and real 3D PET brain studies. Various experimental set-ups in terms of activity distribution and counting statistics were considered. The performance of the algorithm was assessed by calculating figures of merit such as: contrast, coefficient of variation, activity ratio between two regions and full width at half of maximum for resolution measurements. The performance of MRP was compared with that of 3D ordered subsets-expectation maximisation (OSEM) and 3D re-projection (3DRP) algorithms. In all the experimental situations considered, MRP showed: (1) convergence to a stable solution, (2) effectiveness in noise reduction, particularly for low statistics data, (3) good preservation of spatial details. Compared with the OSEM and 3DRP algorithms, MRP provides comparable or better results depending on the parameters used for the reconstruction of the images. (orig.)

  3. Fabrication of 3D nanoimprint stamps with continuous reliefs using dose-modulated electron beam lithography and thermal reflow

    3D electron beam lithography and thermal reflow were combined to fabricate structures with multilevel and continuous profiles. New shapes, smooth surfaces and sharp corners were achieved. By using exposure with variable doses, up to 20 steps were fabricated in a 500 nm thick resist with a lateral resolution of 200 nm. Steps were reflowed into continuous slopes by thermal post-processing, and were transferred into silicon substrates by proportional plasma etching. The method can be used for the fabrication of 3D nanoimprint stamps with both sharp features and continuous profiles.

  4. Evaluation of low-dose limits in 3D-2D rigid registration for surgical guidance

    Uneri, A.; Wang, A. S.; Otake, Y.; Kleinszig, G.; Vogt, S.; Khanna, A. J.; Gallia, G. L.; Gokaslan, Z. L.; Siewerdsen, J. H.

    2014-09-01

    An algorithm for intensity-based 3D-2D registration of CT and C-arm fluoroscopy is evaluated for use in surgical guidance, specifically considering the low-dose limits of the fluoroscopic x-ray projections. The registration method is based on a framework using the covariance matrix adaptation evolution strategy (CMA-ES) to identify the 3D patient pose that maximizes the gradient information similarity metric. Registration performance was evaluated in an anthropomorphic head phantom emulating intracranial neurosurgery, using target registration error (TRE) to characterize accuracy and robustness in terms of 95% confidence upper bound in comparison to that of an infrared surgical tracking system. Three clinical scenarios were considered: (1) single-view image + guidance, wherein a single x-ray projection is used for visualization and 3D-2D guidance; (2) dual-view image + guidance, wherein one projection is acquired for visualization, combined with a second (lower-dose) projection acquired at a different C-arm angle for 3D-2D guidance; and (3) dual-view guidance, wherein both projections are acquired at low dose for the purpose of 3D-2D guidance alone (not visualization). In each case, registration accuracy was evaluated as a function of the entrance surface dose associated with the projection view(s). Results indicate that images acquired at a dose as low as 4 μGy (approximately one-tenth the dose of a typical fluoroscopic frame) were sufficient to provide TRE comparable or superior to that of conventional surgical tracking, allowing 3D-2D guidance at a level of dose that is at most 10% greater than conventional fluoroscopy (scenario #2) and potentially reducing the dose to approximately 20% of the level in a conventional fluoroscopically guided procedure (scenario #3).

  5. An Interactive 3D Virtual Anatomy Puzzle for Learning and Simulation - Initial Demonstration and Evaluation.

    Messier, Erik; Wilcox, Jascha; Dawson-Elli, Alexander; Diaz, Gabriel; Linte, Cristian A

    2016-01-01

    To inspire young students (grades 6-12) to become medical practitioners and biomedical engineers, it is necessary to expose them to key concepts of the field in a way that is both exciting and informative. Recent advances in medical image acquisition, manipulation, processing, visualization, and display have revolutionized the approach in which the human body and internal anatomy can be seen and studied. It is now possible to collect 3D, 4D, and 5D medical images of patient specific data, and display that data to the end user using consumer level 3D stereoscopic display technology. Despite such advancements, traditional 2D modes of content presentation such as textbooks and slides are still the standard didactic equipment used to teach young students anatomy. More sophisticated methods of display can help to elucidate the complex 3D relationships between structures that are so often missed when viewing only 2D media, and can instill in students an appreciation for the interconnection between medicine and technology. Here we describe the design, implementation, and preliminary evaluation of a 3D virtual anatomy puzzle dedicated to helping users learn the anatomy of various organs and systems by manipulating 3D virtual data. The puzzle currently comprises several components of the human anatomy and can be easily extended to include additional organs and systems. The 3D virtual anatomy puzzle game was implemented and piloted using three display paradigms - a traditional 2D monitor, a 3D TV with active shutter glass, and the DK2 version Oculus Rift, as well as two different user interaction devices - a space mouse and traditional keyboard controls. PMID:27046584

  6. International training program: 3D S.UN.COP - Scaling, uncertainty and 3D thermal-hydraulics/neutron-kinetics coupled codes seminar

    Thermal-hydraulic system computer codes are extensively used worldwide for analysis of nuclear facilities by utilities, regulatory bodies, nuclear power plant designers and vendors, nuclear fuel companies, research organizations, consulting companies, and technical support organizations. The computer code user represents a source of uncertainty that can influence the results of system code calculations. This influence is commonly known as the 'user effect' and stems from the limitations embedded in the codes as well as from the limited capability of the analysts to use the codes. Code user training and qualification is an effective means for reducing the variation of results caused by the application of the codes by different users. This paper describes a systematic approach to training code users who, upon completion of the training, should be able to perform calculations making the best possible use of the capabilities of best estimate codes. In other words, the program aims at contributing towards solving the problem of user effect. The 3D S.UN.COP 2005 (Scaling, Uncertainty and 3D COuPled code calculations) seminar has been organized by University of Pisa and University of Zagreb as follow-up of the proposal to IAEA for the Permanent Training Course for System Code Users (D'Auria, 1998). It was recognized that such a course represented both a source of continuing education for current code users and a means for current code users to enter the formal training structure of a proposed 'permanent' stepwise approach to user training. The seminar-training was successfully held with the participation of 19 persons coming from 9 countries and 14 different institutions (universities, vendors, national laboratories and regulatory bodies). More than 15 scientists were involved in the organization of the seminar, presenting theoretical aspects of the proposed methodologies and holding the training and the final examination. A certificate (LA Code User grade) was released

  7. International Training Program: 3D S. Un. Cop - Scaling, Uncertainty and 3D Thermal-Hydraulics/Neutron-Kinetics Coupled Codes Seminar

    Thermal-hydraulic system computer codes are extensively used worldwide for analysis of nuclear facilities by utilities, regulatory bodies, nuclear power plant designers and vendors, nuclear fuel companies, research organizations, consulting companies, and technical support organizations. The computer code user represents a source of uncertainty that can influence the results of system code calculations. This influence is commonly known as the 'user effect' and stems from the limitations embedded in the codes as well as from the limited capability of the analysts to use the codes. Code user training and qualification is an effective means for reducing the variation of results caused by the application of the codes by different users. This paper describes a systematic approach to training code users who, upon completion of the training, should be able to perform calculations making the best possible use of the capabilities of best estimate codes. In other words, the program aims at contributing towards solving the problem of user effect. The 3D S.UN.COP (Scaling, Uncertainty and 3D COuPled code calculations) seminars have been organized as follow-up of the proposal to IAEA for the Permanent Training Course for System Code Users (D'Auria, 1998). Four seminars have been held at University of Pisa (2003, 2004), at The Pennsylvania State University (2004) and at University of Zagreb (2005). It was recognized that such courses represented both a source of continuing education for current code users and a mean for current code users to enter the formal training structure of a proposed 'permanent' stepwise approach to user training. The 3D S.UN.COP 2005 was successfully held with the participation of 19 persons coming from 9 countries and 14 different institutions (universities, vendors, national laboratories and regulatory bodies). More than 15 scientists were involved in the organization of the seminar, presenting theoretical aspects of the proposed methodologies and

  8. International Training Program in Support of Safety Analysis: 3D S.UN.COP-Scaling, Uncertainty and 3D Thermal-Hydraulics/Neutron-Kinetics Coupled Codes Seminars

    Thermal-hydraulic system computer codes are extensively used worldwide for analysis of nuclear facilities by utilities, regulatory bodies, nuclear power plant designers and vendors, nuclear fuel companies, research organizations, consulting companies, and technical support organizations. The computer code user represents a source of uncertainty that can influence the results of system code calculations. This influence is commonly known as the 'user effect' and stems from the limitations embedded in the codes as well as from the limited capability of the analysts to use the codes. Code user training and qualification is an effective means for reducing the variation of results caused by the application of the codes by different users. This paper describes a systematic approach to training code users who, upon completion of the training, should be able to perform calculations making the best possible use of the capabilities of best estimate codes. In other words, the program aims at contributing towards solving the problem of user effect. The 3D S.UN.COP (Scaling, Uncertainty and 3D COuPled code calculations) seminars have been organized as follow-up of the proposal to IAEA for the Permanent Training Course for System Code Users [1]. Five seminars have been held at University of Pisa (2003, 2004), at The Pennsylvania State University (2004), at University of Zagreb (2005) and at the School of Industrial Engineering of Barcelona (2006). It was recognized that such courses represented both a source of continuing education for current code users and a mean for current code users to enter the formal training structure of a proposed 'permanent' stepwise approach to user training. The 3D S.UN.COP 2006 was successfully held with the attendance of 33 participants coming from 18 countries and 28 different institutions (universities, vendors, national laboratories and regulatory bodies). More than 30 scientists (coming from 13 countries and 23 different institutions) were

  9. International training program in support of safety analysis. 3D S.UN.COP-scaling uncertainty and 3D thermal-hydraulics/neutron-kinetics coupled codes seminars

    Thermal-hydraulic system computer codes are extensively used worldwide for analysis of nuclear facilities by utilities, regulatory bodies, nuclear power plant designers and vendors, nuclear fuel companies, research organizations, consulting companies, and technical support organizations. The computer code user represents a source of uncertainty that can influence the results of system code calculations. This influence is commonly known as the user effect' and stems from the limitations embedded in the codes as well as from the limited capability of the analysis to use the codes. Code user training and qualification is an effective means for reducing the variation of results caused by the application of the codes by different users. This paper describes a systematic approach to training code users who, upon completion of the training, should be able to perform calculations making the best possible use of the capabilities of best estimate codes. In other words, the program aims at contributing towards solving the problem of user effect. The 3D S.UN.COP (Scaling, Uncertainty and 3D COuPled code calculations) seminars have been organized as follow-up of the proposal to IAEA for the Permanent Training Course for System Code Users. Six seminars have been held at University of Pisa (2003, 2004), at The Pennsylvania State University (2004), at University of Zagreb (2005), at the School of Industrial Engineering of Barcelona (January-February 2006) and in Buenos Aires, Argentina (October 2006), being this last one requested by ARN (Autoridad Regulatoria Nuclear), NA-SA (Nucleoelectrica Argentina S.A) and CNEA (Comision Nacional de Energia Atomica). It was recognized that such courses represented both a source of continuing education for current code users and a mean for current code users to enter the formal training structure of a proposed 'permanent' stepwise approach to user training. The 3D S.UN.COP 2006 in Barcelona was successfully held with the attendance of 33

  10. Soft Tissue Stability around Single Implants Inserted to Replace Maxillary Lateral Incisors: A 3D Evaluation

    Mangano, F. G.; Picciocchi, G.; Park, K. B.

    2016-01-01

    Purpose. To evaluate the soft tissue stability around single implants inserted to replace maxillary lateral incisors, using an innovative 3D method. Methods. We have used reverse-engineering software for the superimposition of 3D surface models of the dentogingival structures, obtained from intraoral scans of the same patients taken at the delivery of the final crown (S1) and 2 years later (S2). The assessment of soft tissues changes was performed via calculation of the Euclidean surface distances between the 3D models, after the superimposition of S2 on S1; colour maps were used for quantification of changes. Results. Twenty patients (8 males, 12 females) were selected, 10 with a failing/nonrestorable lateral incisor (test group: immediate placement in postextraction socket) and 10 with a missing lateral incisor (control group: conventional placement in healed ridge). Each patient received one immediately loaded implant (Anyridge®, Megagen, Gyeongbuk, South Korea). The superimposition of the 3D surface models taken at different times (S2 over S1) revealed a mean (±SD) reduction of 0.057 mm (±0.025) and 0.037 mm (±0.020) for test and control patients, respectively. This difference was not statistically significant (p = 0.069). Conclusions. The superimposition of the 3D surface models revealed an excellent peri-implant soft tissue stability in both groups of patients, with minimal changes registered along time. PMID:27298621

  11. On the evaluation of photogrammetric methods for dense 3D surface reconstruction in a metrological context

    Toschi, I.; Capra, A.; De Luca, L.; Beraldin, J.-A.; Cournoyer, L.

    2014-05-01

    This paper discusses a methodology to evaluate the accuracy of recently developed image-based 3D modelling techniques. So far, the emergence of these novel methods has not been supported by the definition of an internationally recognized standard which is fundamental for user confidence and market growth. In order to provide an element of reflection and solution to the different communities involved in 3D imaging, a promising approach is presented in this paper for the assessment of both metric quality and limitations of an open-source suite of tools (Apero/MicMac), developed for the extraction of dense 3D point clouds from a set of unordered 2D images. The proposed procedural workflow is performed within a metrological context, through inter-comparisons with "reference" data acquired with two hemispherical laser scanners, one total station, and one laser tracker. The methodology is applied to two case studies, designed in order to analyse the software performances in dealing with both outdoor and environmentally controlled conditions, i.e. the main entrance of Cathédrale de la Major (Marseille, France) and a custom-made scene located at National Research Council of Canada 3D imaging Metrology Laboratory (Ottawa). Comparative data and accuracy evidence produced for both tests allow the study of some key factors affecting 3D model accuracy.

  12. 3D evaluation of palatal rugae for human identification using digital study models

    Taneva, Emilia D.; Johnson, Andrew; Viana, Grace; Evans, Carla A.

    2015-01-01

    Background: While there is literature suggesting that the palatal rugae could be used for human identification, most of these studies use two-dimensional (2D) approach. Aim: The aims of this study were to evaluate palatal ruga patterns using three-dimensional (3D) digital models; compare the most clinically relevant digital model conversion techniques for identification of the palatal rugae; develop a protocol for overlay registration; determine changes in palatal ruga individual patterns through time; and investigate the efficiency and accuracy of 3D matching processes between different individuals’ patterns. Material and Methods: Five cross sections in the anteroposterior dimension and four cross sections in the transverse dimension were computed which generated 18 2D variables. In addition, 13 3D variables were defined: The posterior point of incisive papilla (IP), and the most medial and lateral end points of the palatal rugae (R1MR, R1ML, R1LR, R1LL, R2MR, R2ML, R2LR, R2LL, R3MR, R3ML, R3LR, and R3LL). The deviation magnitude for each variable was statistically analyzed in this study. Five different data sets with the same 31 landmarks were evaluated in this study. Results: The results demonstrated that 2D images and linear measurements in the anteroposterior and transverse dimensions were not sufficient for comparing different digital model conversion techniques using the palatal rugae. 3D digital models proved to be a highly effective tool in evaluating different palatal ruga patterns. The 3D landmarks showed no statistically significant mean differences over time or as a result of orthodontic treatment. No statistically significant mean differences were found between different digital model conversion techniques, that is, between OrthoCAD™ and Ortho Insight 3D™, and between Ortho Insight 3D™ and the iTero® scans, when using 12 3D palatal rugae landmarks for comparison. Conclusion: Although 12 palatal 3D landmarks could be used for human

  13. Evaluation of cartilage surface injuries using 3D-double echo steady state (3D-DESS): Effect of changing flip angle from 40 deg to 90 deg

    Background. In magnetic resonance imaging (MRI) with 3D-double-echo steady-state (3D-DESS) sequences, the cartilage-synovial fluid contrast is reported to be better with a flip angle of 90 deg than with the conventional flip angle of 40 deg, and the detection rate of knee cartilage injury may be improved. Purpose. To compare the diagnostic performance and certainty of diagnosis with 3D-DESS images made using two flip angle settings, 40 deg and 90 deg, for knee cartilage surface lesions of Grade 2 or above confirmed by arthroscopy. Material and Methods. Images were obtained with 3D-DESS flip angles of 40 deg and 90 deg at 1.0T in 13 consecutive patients (2 men, 11 women, age range 18-68 years) evaluated for superficial cartilage injury by arthroscopy. Two radiologists classified the presence or absence of cartilage damage of ≥Grade 2 as 'positive (p)' or 'negative (n)', respectively. The rate of agreement with arthroscopic diagnosis was then examined, and the diagnostic performance compared. Diagnostic confidence was assessed scoring the presence or absence of cartilage damage into three categories: 3 = can diagnose with absolute confidence; 2 = can diagnose with a level of certainty as probably present or probably absent; and 1 = cannot make a diagnosis. Results. In a comparison of the rate of agreement between diagnosis by 3D-DESS images and arthroscopy, the rate of agreement was significantly higher and diagnostic performance was better in 90 deg images for the medial femoral condyle only. Diagnostic confidence was significantly better with 90 deg flip angle images than with 40 deg flip angle images for all six cartilage surfaces. Conclusion. In evaluating knee cartilage surface lesions with 3D-DESS sequences, a flip angle setting of 90 deg is more effective than the conventional setting of 40 deg

  14. Evaluation of cartilage surface injuries using 3D-double echo steady state (3D-DESS): Effect of changing flip angle from 40 deg to 90 deg

    Moriya, Susumu; Yokobayashi, Tsuneo; Ishikawa, Mitsunori (Ishikawa Clinic, Kyoto (Japan)), email: smoyari@yahoo.co.jp; Miki, Yukio (Dept. of Radiology, Osaka City Univ. Graduate School of Medicine, Osaka (Japan)); Kanagaki, Mitsunori; Yamamoto, Akira (Dept. of Diagnostic Imaging and Nuclear Medicine, Kyoto Univ., Kyoto (Japan)); Okudaira, Shuzo (Dept. of Orthopaedics, Kyoto Police Hospital, Kyoto (Japan)); Nakamura, Shinichiro (Center for Musculoskeletal Research, Univ. of Tennessee, Knoxville, TN (United States))

    2011-12-15

    Background. In magnetic resonance imaging (MRI) with 3D-double-echo steady-state (3D-DESS) sequences, the cartilage-synovial fluid contrast is reported to be better with a flip angle of 90 deg than with the conventional flip angle of 40 deg, and the detection rate of knee cartilage injury may be improved. Purpose. To compare the diagnostic performance and certainty of diagnosis with 3D-DESS images made using two flip angle settings, 40 deg and 90 deg, for knee cartilage surface lesions of Grade 2 or above confirmed by arthroscopy. Material and Methods. Images were obtained with 3D-DESS flip angles of 40 deg and 90 deg at 1.0T in 13 consecutive patients (2 men, 11 women, age range 18-68 years) evaluated for superficial cartilage injury by arthroscopy. Two radiologists classified the presence or absence of cartilage damage of >=Grade 2 as 'positive (p)' or 'negative (n)', respectively. The rate of agreement with arthroscopic diagnosis was then examined, and the diagnostic performance compared. Diagnostic confidence was assessed scoring the presence or absence of cartilage damage into three categories: 3 = can diagnose with absolute confidence; 2 = can diagnose with a level of certainty as probably present or probably absent; and 1 = cannot make a diagnosis. Results. In a comparison of the rate of agreement between diagnosis by 3D-DESS images and arthroscopy, the rate of agreement was significantly higher and diagnostic performance was better in 90 deg images for the medial femoral condyle only. Diagnostic confidence was significantly better with 90 deg flip angle images than with 40 deg flip angle images for all six cartilage surfaces. Conclusion. In evaluating knee cartilage surface lesions with 3D-DESS sequences, a flip angle setting of 90 deg is more effective than the conventional setting of 40 deg

  15. A Novel 3D Thermal Impedance Model for High Power Modules Considering Multi-layer Thermal Coupling and Different Heating/Cooling Conditions

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    accurate temperature estimation either vertically or horizontally inside the power devices is still hard to identify. This paper investigates the thermal behavior of high power module in various operating conditions by means of Finite Element Method (FEM). A novel 3D thermal impedance network considering...... the multi-layer thermal coupling among chips is proposed. The impacts to the thermal impedance by various cooling and heating conditions are also studied. It is concluded that the heating and cooling conditions will have influence on the junction to case thermal impedances and need to be carefully...... considered in the thermal modelling. The proposed 3D thermal impedance network and the extraction procedure are verified in a circuit simulator and shows to be much faster with the same accuracy compared to FEM simulation. This network can be used for life-time estimation of IGBT module considering the whole...

  16. A method for the evaluation of thousands of automated 3D stem cell segmentations.

    Bajcsy, P; Simon, M; Florczyk, S J; Simon, C G; Juba, D; Brady, M C

    2015-12-01

    There is no segmentation method that performs perfectly with any dataset in comparison to human segmentation. Evaluation procedures for segmentation algorithms become critical for their selection. The problems associated with segmentation performance evaluations and visual verification of segmentation results are exaggerated when dealing with thousands of three-dimensional (3D) image volumes because of the amount of computation and manual inputs needed. We address the problem of evaluating 3D segmentation performance when segmentation is applied to thousands of confocal microscopy images (z-stacks). Our approach is to incorporate experimental imaging and geometrical criteria, and map them into computationally efficient segmentation algorithms that can be applied to a very large number of z-stacks. This is an alternative approach to considering existing segmentation methods and evaluating most state-of-the-art algorithms. We designed a methodology for 3D segmentation performance characterization that consists of design, evaluation and verification steps. The characterization integrates manual inputs from projected surrogate 'ground truth' of statistically representative samples and from visual inspection into the evaluation. The novelty of the methodology lies in (1) designing candidate segmentation algorithms by mapping imaging and geometrical criteria into algorithmic steps, and constructing plausible segmentation algorithms with respect to the order of algorithmic steps and their parameters, (2) evaluating segmentation accuracy using samples drawn from probability distribution estimates of candidate segmentations and (3) minimizing human labour needed to create surrogate 'truth' by approximating z-stack segmentations with 2D contours from three orthogonal z-stack projections and by developing visual verification tools. We demonstrate the methodology by applying it to a dataset of 1253 mesenchymal stem cells. The cells reside on 10 different types of biomaterial

  17. A 3D Osteoblast In Vitro Model for the Evaluation of Biomedical Materials

    Luciana Restle; Daniela Costa-Silva; Emanuelle Stellet Lourenço; Rober Freitas Bachinski; Ana Carolina Batista; Adriana Brandão Ribeiro Linhares; Gutemberg Gomes Alves

    2015-01-01

    Biomedical materials for bone therapy are usually assessed for their biocompatibility and safety employing animal models or in vitro monolayer cell culture assays. However, alternative in vitro models may offer controlled conditions closer to physiological responses and reduce animal testing. In this work, we developed a 3D spheroidal cell culture with potential to evaluate simultaneously material-cell and cell-cell interactions. Different cell densities of murine MC3T3-E1 preosteoblasts or h...

  18. Preoperative evaluation of the saphenous vein by 3-D contrastless computed tomography

    Maruyama, Yuji; Imura, Hajime; Shirakawa, Makoto; Ochi, Masami

    2013-01-01

    Volume-rendering computed tomography (CT) without contrast medium has clearly demonstrated the 3-D mapping of the saphenous vein (SV). Contrastless volume-rendering CT was used to preoperatively evaluate the SV anatomy before coronary artery bypass grafting (CABG). This technique was useful for atypical anatomical variations, such as partial duplication of SV (Case 1) or varicose veins (Case 2). Volume-rendering CT may also help with redo CABG (to determine remaining SV) or during endoscopic ...

  19. Design and evaluation of a laboratory prototype system for 3D photoacoustic full breast tomography

    Xia, W; Piras, D; Singh, M. K. A.; van Hespen, J. C. G.; Van Leeuwen, T. G.; Steenbergen, W Van; Manohar, S.

    2013-01-01

    Photoacoustic imaging can visualize vascularization-driven optical absorption contrast with great potential for breast cancer detection and diagnosis. State-of-the-art photoacoustic breast imaging systems are promising but are limited either by only a 2D imaging capability or by an insufficient imaging field-of-view (FOV). We present a laboratory prototype system designed for 3D photoacoustic full breast tomography, and comprehensively characterize it and evaluate its performance in imaging p...

  20. Evaluation of an improved algorithm for producing realistic 3D breast software phantoms: Application for mammography

    Bliznakova, K.; Suryanarayanan, S.; Karellas, A.; Pallikarakis, N. [Department of Medical Physics, School of Medicine, University of Patras, 26500 Rio-Patras (Greece); Department of Radiology and Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322 (United States); Department of Medical Physics, School of Medicine, University of Patras, 26500 Rio-Patras (Greece)

    2010-11-15

    Purpose: This work presents an improved algorithm for the generation of 3D breast software phantoms and its evaluation for mammography. Methods: The improved methodology has evolved from a previously presented 3D noncompressed breast modeling method used for the creation of breast models of different size, shape, and composition. The breast phantom is composed of breast surface, duct system and terminal ductal lobular units, Cooper's ligaments, lymphatic and blood vessel systems, pectoral muscle, skin, 3D mammographic background texture, and breast abnormalities. The key improvement is the development of a new algorithm for 3D mammographic texture generation. Simulated images of the enhanced 3D breast model without lesions were produced by simulating mammographic image acquisition and were evaluated subjectively and quantitatively. For evaluation purposes, a database with regions of interest taken from simulated and real mammograms was created. Four experienced radiologists participated in a visual subjective evaluation trial, as they judged the quality of the simulated mammograms, using the new algorithm compared to mammograms, obtained with the old modeling approach. In addition, extensive quantitative evaluation included power spectral analysis and calculation of fractal dimension, skewness, and kurtosis of simulated and real mammograms from the database. Results: The results from the subjective evaluation strongly suggest that the new methodology for mammographic breast texture creates improved breast models compared to the old approach. Calculated parameters on simulated images such as {beta} exponent deducted from the power law spectral analysis and fractal dimension are similar to those calculated on real mammograms. The results for the kurtosis and skewness are also in good coincidence with those calculated from clinical images. Comparison with similar calculations published in the literature showed good agreement in the majority of cases. Conclusions

  1. System-Level Thermal Modeling and Management for Multi-Core and 3D Microprocessors

    Liu, Zao

    2014-01-01

    The continuously scaling down of CMOS technology inevitably increases the power density for high performance microprocessors, which makes thermal effects and related problems urgent and challenging. Unpredicted thermal behavior and on-chip thermal hot spots could lead to performance degradation of microprocessor chips, incurring reliability issues. Hence, it is becoming increasingly important to develop thermal modeling methods to predict the thermal behavior of microprocessor chips, and ther...

  2. Investigation of seasonal thermal flow in a real dam reservoir using 3-D numerical modeling

    Üneş Fatih

    2015-03-01

    Full Text Available Investigations indicate that correct estimation of seasonal thermal stratification in a dam reservoir is very important for the dam reservoir water quality modeling and water management problems. The main aim of this study is to develop a hydrodynamics model of an actual dam reservoir in three dimensions for simulating a real dam reservoir flows for different seasons. The model is developed using nonlinear and unsteady continuity, momentum, energy and k-ε turbulence model equations. In order to include the Coriolis force effect on the flow in a dam reservoir, Coriolis force parameter is also added the model equations. Those equations are constructed using actual dimensions, shape, boundary and initial conditions of the dam and reservoir. Temperature profiles and flow visualizations are used to evaluate flow conditions in the reservoir. Reservoir flow’s process and parameters are determined all over the reservoir. The mathematical model developed is capable of simulating the flow and thermal characteristics of the reservoir system for seasonal heat exchanges. Model simulations results obtained are compared with field measurements obtained from gauging stations for flows in different seasons. The results show a good agreement with the field measurements.

  3. Coupled 3-D kinetics thermal-hydraulic analysis of Hot Zero Power main steam line breaks using RETRAN and STAR codes

    The Main Steam Line Break (MSLB) at End of Life (EOL), Hot Zero Power (HZP) conditions accident was analyzed using a fully time-dependent coupled thermal-hydraulic (T/H) and neutronics method, and compared against conservative Final Safety Analysis Report (FSAR) results, which predict a return-to-power. The development and improvement of coupled neutronics/T/H analysis techniques provide many advantages including the capability to evaluate the impact of modeling assumptions made in previous reactor kinetics and T/H calculations. The coupled STAR kinetics and RETRAN T/H techniques developed here provides a means to evaluate the quasi-static, point kinetics approximation against a fully time-dependent, three-dimensional approach. Using the state-of-the-art 3-D STAR reactor kinetics code with the RETRAN reactor coolant system (RCS) T/H code in a best-estimate approach, it is now possible to evaluate the impact on safety margins imposed by conservative FSAR MSLB assumptions. The method presented shows how the time-dependent 3-D STAR nodal code model was used directly with core inlet conditions determined by RETRAN for a Westinghouse PWR. The STAR/RETRAN results clearly demonstrate that a return-to-power is NOT predicted when a 3-D thermal-hydraulically coupled time-dependent kinetics approach is used. This study shows that: (a) quasi-static and point kinetics methods are not able to describe severe PWR asymmetric transient phenomena adequately; and (b) fully coupled, 3-D time-dependent analysis methods should be used for PWR reactor transients instead. By coupling the RCS response in terms of updated core inlet conditions with 3-D time-dependent core kinetics response, in a tandem manner, the core power and T/H RCS conditions are forced to be self-consistent during the entire event, when non-equilibrium conditions exist. (orig.)

  4. Uncertainty propagation in a 3-D thermal code for performance assessment of a nuclear waste disposal

    Given the very large time scale involved, the performance assessment of a nuclear waste repository requires numerical modelling. Because we are uncertain of the exact value of the input parameters, we have to analyse the impact of these uncertainties on the outcome of the physical models. The EDF Division Research and Development has set a reliability method to propagate these uncertainties or variability through models which requires much less physical simulations than the usual simulation methods. We apply the reliability method MEFISTO to a base case modelling the heat transfers in a virtual disposal in the future site of the French underground research laboratory, in the East of France. This study is led in collaboration with ANDRA which is the French Nuclear Waste Management Agency. With this exercise, we want to evaluate the thermal behaviour of a concept related to the variation of physical parameters and their uncertainty. (author)

  5. A magnetic resonance study of 3d transition metals and thermal donors in silicon

    This thesis describes a study of 3d-transition metal impurities in silicon (titanium and iron in particular) and a study of oxygen-related heat-treatment centers in silicon, both carried out mainly by magnetic resonances techniques like EPR and ENDOR. 119 refs.; 31 figs.; 14 tabs

  6. Error Evaluation in a Stereovision-Based 3D Reconstruction System

    Kohler Sophie

    2010-01-01

    Full Text Available The work presented in this paper deals with the performance analysis of the whole 3D reconstruction process of imaged objects, specifically of the set of geometric primitives describing their outline and extracted from a pair of images knowing their associated camera models. The proposed analysis focuses on error estimation for the edge detection process, the starting step for the whole reconstruction procedure. The fitting parameters describing the geometric features composing the workpiece to be evaluated are used as quality measures to determine error bounds and finally to estimate the edge detection errors. These error estimates are then propagated up to the final 3D reconstruction step. The suggested error analysis procedure for stereovision-based reconstruction tasks further allows evaluating the quality of the 3D reconstruction. The resulting final error estimates enable lastly to state if the reconstruction results fulfill a priori defined criteria, for example, fulfill dimensional constraints including tolerance information, for vision-based quality control applications for example.

  7. Atmospheric correction of thermal-infrared imagery of the 3-D urban environment acquired in oblique viewing geometry

    F. Meier; D. Scherer; Richters, J.; A. Christen

    2010-01-01

    This research quantifies and discusses atmospheric effects that alter the radiance observed by a ground-based thermal-infrared (TIR) camera mounted on top of a high-rise building in the city of Berlin, Germany. The study shows that atmospheric correction of ground-based TIR imagery of the three-dimensional (3-D) urban environment acquired in oblique viewing geometry has to account for spatial variability of line-of-sight (LOS) geometry. We present an atmospheric correction procedure t...

  8. 3-D TECATE/BREW: Thermal, stress, and birefringent ray-tracing codes for solid-state laser design

    This report describes the physics, code formulations, and numerics that are used in the TECATE (totally Eulerian code for anisotropic thermo-elasticity) and BREW (birefringent ray-tracing of electromagnetic waves) codes for laser design. These codes resolve thermal, stress, and birefringent optical effects in 3-D stationary solid-state systems. This suite of three constituent codes is a package referred to as LASRPAK

  9. Automotive Underhood Thermal Management Analysis Using 3-D Coupled Thermal-Hydrodynamic Computer Models: Thermal Radiation Modeling

    Pannala, S; D' Azevedo, E; Zacharia, T

    2002-02-26

    The goal of the radiation modeling effort was to develop and implement a radiation algorithm that is fast and accurate for the underhood environment. As part of this CRADA, a net-radiation model was chosen to simulate radiative heat transfer in an underhood of a car. The assumptions (diffuse-gray and uniform radiative properties in each element) reduce the problem tremendously and all the view factors for radiation thermal calculations can be calculated once and for all at the beginning of the simulation. The cost for online integration of heat exchanges due to radiation is found to be less than 15% of the baseline CHAD code and thus very manageable. The off-line view factor calculation is constructed to be very modular and has been completely integrated to read CHAD grid files and the output from this code can be read into the latest version of CHAD. Further integration has to be performed to accomplish the same with STAR-CD. The main outcome of this effort is to obtain a highly scalable and portable simulation capability to model view factors for underhood environment (for e.g. a view factor calculation which took 14 hours on a single processor only took 14 minutes on 64 processors). The code has also been validated using a simple test case where analytical solutions are available. This simulation capability gives underhood designers in the automotive companies the ability to account for thermal radiation - which usually is critical in the underhood environment and also turns out to be one of the most computationally expensive components of underhood simulations. This report starts off with the original work plan as elucidated in the proposal in section B. This is followed by Technical work plan to accomplish the goals of the project in section C. In section D, background to the current work is provided with references to the previous efforts this project leverages on. The results are discussed in section 1E. This report ends with conclusions and future scope of

  10. Heavy Ion Induced SEU Sensitivity Evaluation of 3D Integrated SRAMs

    Cao, Xuebing; Huo, Mingxue; Wang, Tianqi; Li, Anlong; Qi, Chunhua; Wang, Jinxiang

    2016-01-01

    Heavy ions induced single event upset (SEU) sensitivity of three-dimensional integrated SRAMs are evaluated by using Monte Carlo sumulation methods based on Geant4. The cross sections of SEUs and Multi Cell Upsets (MCUs) for 3D SRAM are simulated by using heavy ions with different energies and LETs. The results show that the sensitivity of different die of 3D SRAM has obvious discrepancies at low LET. Average percentage of MCUs of 3D SRAMs rises from 17.2% to 32.95% when LET increases from 42.19 MeV cm2/mg to 58.57MeV cm2/mg. As for a certain LET, the percentage of MCUs shows a notable distinction between face-to-face structure and back-to-face structure. For back-to-face structure, the percentage of MCUs increases with the deeper die. However, the face-to-face die presents the relatively low percentage of MCUs. The comparison of SEU cross sections for planar SRAMs and experiment data are conducted to indicate the effectiveness of our simulation method. Finally, we compare the upset cross sections of planar p...

  11. On the Efficiency of Image Metrics for Evaluating the Visual Quality of 3D Models.

    Lavoue, Guillaume; Larabi, Mohamed Chaker; Vasa, Libor

    2016-08-01

    3D meshes are deployed in a wide range of application processes (e.g., transmission, compression, simplification, watermarking and so on) which inevitably introduce geometric distortions that may alter the visual quality of the rendered data. Hence, efficient model-based perceptual metrics, operating on the geometry of the meshes being compared, have been recently introduced to control and predict these visual artifacts. However, since the 3D models are ultimately visualized on 2D screens, it seems legitimate to use images of the models (i.e., snapshots from different viewpoints) to evaluate their visual fidelity. In this work we investigate the use of image metrics to assess the visual quality of 3D models. For this goal, we conduct a wide-ranging study involving several 2D metrics, rendering algorithms, lighting conditions and pooling algorithms, as well as several mean opinion score databases. The collected data allow (1) to determine the best set of parameters to use for this image-based quality assessment approach and (2) to compare this approach to the best performing model-based metrics and determine for which use-case they are respectively adapted. We conclude by exploring several applications that illustrate the benefits of image-based quality assessment. PMID:26394428

  12. A system for 3-D absorbed dose measurements with tissue-equivalence for thermal neutrons

    A ferrous sulphate gel with a proper composition to thermalise epithermal neutrons with tissue equivalence with brain tissue gives the possibility of making phantoms which act as a continuous dosimeter for the gamma radiation, with the possibility of 3-D dose determination. If in the phantom a volume of gel containing 10B (in the amount typical for BNCT) is set, information on the absorbed dose in the tumour site may also be drawn. ((orig.))

  13. Development of multidimensional two-fluid model code ACE-3D for evaluation of constitutive equations

    In order to perform design calculations for a passive safety reactor with good accuracy by a multidimensional two-fluid model, we developed an analysis code, ACE-3D, which can apply for evaluation of constitutive equations. The developed code has the following features: 1. The basic equations are based on 3-dimensional two-fluid model and the orthogonal or the cylindrical coordinate system can be selected. The fluid system is air-water or steam-water. 2. The basic equations are formulated by the finite-difference scheme of staggered mesh. The convection term is formulated by an upwind scheme and the diffusion term by a center-difference scheme. 3. Semi-implicit numerical scheme is adopted and the mass and the energy equations are treated equally in convergent steps for Jacobi equations. 4. The interfacial stress term consists of drag force, life force, turbulent dispersion force, wall force and virtual mass force. 5. A κ-ε turbulent model for bubbly flow is incorporated as the turbulent model. The predictive capability of ACE-3D has been verified using a data-base for bubbly flow in a small-scale vertical pipe. In future, the constitutive equations will be improved with a data-base in a large vertical pipe developed in our laboratory and we have a plan to construct a reliable analytical tool through the improvement work, the progress of calculational speed with vector and parallel processing, the assessments for phase change terms and so on. This report describes the outline for the basic equations and the finite-difference equations in ACE-3D code and also the outline for the program structure. Besides, the results for the assessments of ACE-3D code for the small-scale pipe are summarized. (author)

  14. Mining 3D Patterns from Gene Expression Temporal Data: A New Tricluster Evaluation Measure

    David Gutiérrez-Avilés

    2014-01-01

    Full Text Available Microarrays have revolutionized biotechnological research. The analysis of new data generated represents a computational challenge due to the characteristics of these data. Clustering techniques are applied to create groups of genes that exhibit a similar behavior. Biclustering emerges as a valuable tool for microarray data analysis since it relaxes the constraints for grouping, allowing genes to be evaluated only under a subset of the conditions. However, if a third dimension appears in the data, triclustering is the appropriate tool for the analysis. This occurs in longitudinal experiments in which the genes are evaluated under conditions at several time points. All clustering, biclustering, and triclustering techniques guide their search for solutions by a measure that evaluates the quality of clusters. We present an evaluation measure for triclusters called Mean Square Residue 3D. This measure is based on the classic biclustering measure Mean Square Residue. Mean Square Residue 3D has been applied to both synthetic and real data and it has proved to be capable of extracting groups of genes with homogeneous patterns in subsets of conditions and times, and these groups have shown a high correlation level and they are also related to their functional annotations extracted from the Gene Ontology project.

  15. Mining 3D patterns from gene expression temporal data: a new tricluster evaluation measure.

    Gutiérrez-Avilés, David; Rubio-Escudero, Cristina

    2014-01-01

    Microarrays have revolutionized biotechnological research. The analysis of new data generated represents a computational challenge due to the characteristics of these data. Clustering techniques are applied to create groups of genes that exhibit a similar behavior. Biclustering emerges as a valuable tool for microarray data analysis since it relaxes the constraints for grouping, allowing genes to be evaluated only under a subset of the conditions. However, if a third dimension appears in the data, triclustering is the appropriate tool for the analysis. This occurs in longitudinal experiments in which the genes are evaluated under conditions at several time points. All clustering, biclustering, and triclustering techniques guide their search for solutions by a measure that evaluates the quality of clusters. We present an evaluation measure for triclusters called Mean Square Residue 3D. This measure is based on the classic biclustering measure Mean Square Residue. Mean Square Residue 3D has been applied to both synthetic and real data and it has proved to be capable of extracting groups of genes with homogeneous patterns in subsets of conditions and times, and these groups have shown a high correlation level and they are also related to their functional annotations extracted from the Gene Ontology project. PMID:25143987

  16. Investigation and evaluation of pointing modalities for interactive stereoscopic 3D TV

    Haiyue Yuan,; Calic, J.; Fernando, A.; Kondoz, A

    2013-01-01

    The recent proliferation of stereoscopic three dimensional (3D) video technology has fostered a large body of research into 3D video capture, production, compression and delivery. However, little research has been dedicated to the design practices of stereoscopic 3D video interaction. Interaction tasks such as pointing and selection are critical to the consumer's experience of the 3D video technology. This paper presents investigation of pointing modalities in the context of stereoscopic 3D t...

  17. A 3-D thermal regime model suitable for cold accumulation zones of polythermal mountain glaciers

    Gilbert, A; O. Gagliardini; Vincent, C.; Wagnon, Patrick

    2014-01-01

    Analysis of the thermal and mechanical response of high altitude glaciers to climate change is crucial to assess future glacier hazards associated with thermal regime changes. This paper presents a new fully thermo-mechanically coupled transient thermal regime model including enthalpy transport, firn densification, full-Stokes porous flow, free surface evolution, strain heating, surface meltwater percolation, and refreezing. The model is forced by daily air temperature data and can therefore ...

  18. Spectral history model in DYN3D: Verification against coupled Monte-Carlo thermal-hydraulic code BGCore

    Highlights: • Pu-239 based spectral history method was tested on 3D BWR single assembly case. • Burnup of a BWR fuel assembly was performed with the nodal code DYN3D. • Reference solution was obtained by coupled Monte-Carlo thermal-hydraulic code BGCore. • The proposed method accurately reproduces moderator density history effect for BWR test case. - Abstract: This research focuses on the verification of a recently developed methodology accounting for spectral history effects in 3D full core nodal simulations. The traditional deterministic core simulation procedure includes two stages: (1) generation of homogenized macroscopic cross section sets and (2) application of these sets to obtain a full 3D core solution with nodal codes. The standard approach adopts the branch methodology in which the branches represent all expected combinations of operational conditions as a function of burnup (main branch). The main branch is produced for constant, usually averaged, operating conditions (e.g. coolant density). As a result, the spectral history effects that associated with coolant density variation are not taken into account properly. Number of methods to solve this problem (such as micro-depletion and spectral indexes) were developed and implemented in modern nodal codes. Recently, we proposed a new and robust method to account for history effects. The methodology was implemented in DYN3D and involves modification of the few-group cross section sets. The method utilizes the local Pu-239 concentration as an indicator of spectral history. The method was verified for PWR and VVER applications. However, the spectrum variation in BWR core is more pronounced due to the stronger coolant density change. The purpose of the current work is investigating the applicability of the method to BWR analysis. The proposed methodology was verified against recently developed BGCore system, which couples Monte Carlo neutron transport with depletion and thermal-hydraulic solvers and

  19. A preliminary evaluation work on a 3D ultrasound imaging system for 2D array transducer

    Zhong, Xiaoli; Li, Xu; Yang, Jiali; Li, Chunyu; Song, Junjie; Ding, Mingyue; Yuchi, Ming

    2016-04-01

    This paper presents a preliminary evaluation work on a pre-designed 3-D ultrasound imaging system. The system mainly consists of four parts, a 7.5MHz, 24×24 2-D array transducer, the transmit/receive circuit, power supply, data acquisition and real-time imaging module. The row-column addressing scheme is adopted for the transducer fabrication, which greatly reduces the number of active channels . The element area of the transducer is 4.6mm by 4.6mm. Four kinds of tests were carried out to evaluate the imaging performance, including the penetration depth range, axial and lateral resolution, positioning accuracy and 3-D imaging frame rate. Several strong reflection metal objects , fixed in a water tank, were selected for the purpose of imaging due to a low signal-to-noise ratio of the transducer. The distance between the transducer and the tested objects , the thickness of aluminum, and the seam width of the aluminum sheet were measured by a calibrated micrometer to evaluate the penetration depth, the axial and lateral resolution, respectively. The experiment al results showed that the imaging penetration depth range was from 1.0cm to 6.2cm, the axial and lateral resolution were 0.32mm and 1.37mm respectively, the imaging speed was up to 27 frames per second and the positioning accuracy was 9.2%.

  20. Plaque characterization in ex vivo MRI evaluated by dense 3D correspondence with histology

    Engelen, A. van; de Bruijne, Marleen; Klein, S.;

    2011-01-01

    . Histological slices of human atherosclerotic plaques were manually segmented into necrotic core, fibrous tissue and calcification. Classification of these three components was voxelwise evaluated. As features the intensity, gradient magnitude and Laplacian in four MRI sequences after different degrees of......Automatic quantification of carotid artery plaque composition is important in the development of methods that distinguish vulnerable from stable plaques. MRI has shown to be capable of imaging different components noninvasively. We present a new plaque classification method which uses 3D...... registration of histology data with ex vivo MRI data, using non-rigid registration, both for training and evaluation. This is more objective than previously presented methods, as it eliminates selection bias that is introduced when 2D MRI slices are manually matched to histological slices before evaluation...

  1. Evaluation of PC-ISO for customized, 3D Printed, gynecologic 192-Ir HDR brachytherapy applicators.

    Cunha, J Adam M; Mellis, Katherine; Sethi, Rajni; Siauw, Timmy; Sudhyadhom, Atchar; Garg, Animesh; Goldberg, Ken; Hsu, I-Chow; Pouliot, Jean

    2015-01-01

    The purpose of this study was to evaluate the radiation attenuation properties of PC-ISO, a commercially available, biocompatible, sterilizable 3D printing material, and its suitability for customized, single-use gynecologic (GYN) brachytherapy applicators that have the potential for accurate guiding of seeds through linear and curved internal channels. A custom radiochromic film dosimetry apparatus was 3D-printed in PC-ISO with a single catheter channel and a slit to hold a film segment. The apparatus was designed specifically to test geometry pertinent for use of this material in a clinical setting. A brachytherapy dose plan was computed to deliver a cylindrical dose distribution to the film. The dose plan used an 192Ir source and was normalized to 1500 cGy at 1 cm from the channel. The material was evaluated by comparing the film exposure to an identical test done in water. The Hounsfield unit (HU) distributions were computed from a CT scan of the apparatus and compared to the HU distribution of water and the HU distribution of a commercial GYN cylinder applicator. The dose depth curve of PC-ISO as measured by the radiochromic film was within 1% of water between 1 cm and 6 cm from the channel. The mean HU was -10 for PC-ISO and -1 for water. As expected, the honeycombed structure of the PC-ISO 3D printing process created a moderate spread of HU values, but the mean was comparable to water. PC-ISO is sufficiently water-equivalent to be compatible with our HDR brachytherapy planning system and clinical workflow and, therefore, it is suitable for creating custom GYN brachytherapy applicators. Our current clinical practice includes the use of custom GYN applicators made of commercially available PC-ISO when doing so can improve the patient's treatment.  PMID:25679174

  2. A coupled 3D neutron kinetics/thermal-hydraulics model of the generation IV sodium-cooled fast reactor

    The Generation IV Sodium-cooled Fast Reactor (SFR) is an advanced fast-spectrum reactor concept being studied in the frame of international collaborations such as the Generation IV International Forum and European Union Framework Programmes. The present paper reports on the development and validation of a coupled 3D neutron kinetics / thermal-hydraulics model of a 3600 MWth SFR core being designed at CEA. The work has been performed in preparation for the analysis of transient core behavior in relation to hypothetical sodium boiling events, e.g. following an unprotected loss-of-flow (ULOF) accident or an unprotected transient overpower (UTOP) accident. The coupled 3D core model was developed in the frame of PSI's FAST code system, principally using the TRACE and PARCS codes. The neutronic data necessary for the 3D kinetics model in PARCS were derived from ERANOS-2.1 calculations. The standalone neutronics (PARCS) and thermal-hydraulics (TRACE) models were coupled by means of an external mapping scheme, and coupled simulations were performed to obtain steady-state and null-transient solutions for different core states. The principal neutronic parameters, mainly the effective multiplication factor and reactivity coefficients, were computed and validated against static ERANOS-2.1 calculations. Good agreement was obtained in each case. (authors)

  3. Searching for Thermal Anomalies on Icy Satellites: Step 1- Validation of the Three Dimensional Volatile-Transport (VT3D)

    Simmons, Gary G.; Howett, Carly J. A.; Young, Leslie A.; Spencer, John R.

    2015-11-01

    In the last few decades, thermal data from the Galileo and Cassini spacecraft have detected various anomalies on Jovian and Saturnian satellites, including the thermally anomalous “PacMan” regions on Mimas and Tethys and the Pwyll anomaly on Europa (Howett et al. 2011, Howett et al. 2012, Spencer et al. 1999). Yet, the peculiarities of some of these anomalies, like the weak detection of the “PacMan” anomalies on Rhea and Dione and the low thermal inertia values of the widespread anomalies on equatorial Europa, are subjects for on-going research (Howett et al. 2014, Rathbun et al. 2010). Further, analysis and review of all the data both Galileo and Cassini took of these worlds will provide information of the thermal inertia and albedos of their surfaces, perhaps highlighting potential targets of interest for future Jovian and Saturnian system missions. Many previous works have used a thermophysical model for airless planets developed by Spencer (1990). However, the Three Dimensional Volatile-Transport (VT3D) model proposed by Young (2012) is able to predict surface temperatures in significantly faster computation time, incorporating seasonal and diurnal insolation variations. This work is the first step in an ongoing investigation, which will use VT3D’s capabilities to reanalyze Galileo and Cassini data. VT3D, which has already been used to analyze volatile transport on Pluto, is validated by comparing its results to that of the Spencer thermal model. We will also present our initial results using VT3D to reanalyze the thermophysical properties of the PacMan anomaly previous discovered on Mimas by Howett et al. (2011), using temperature constraints of diurnal data from Cassini/CIRS. VT3D is expected to be an efficient tool in identifying new thermal anomalies in future Saturnian and Jovian missions.Bibliography:C.J.A. Howett et al. (2011), Icarus 216, 221.C.J.A. Howett et al. (2012), Icarus 221, 1084.C.J.A. Howett et al. (2014), Icarus 241, 239.J

  4. Development of the coupled 3D neutron kinetics/thermal-hydraulics code DYN3D-HTR for the simulation of transients in block-type HTGR

    The Light Water Reactor (LWR) dynamics code DYN3D is extended and adopted for the application to block-type High Temperature Gas-Cooled Reactor (HTGR). A procedure for the cross section generation for the HTGR core calculations was developed. The modified Reactivity-Equivalent Physical Transformation (RPT) approach is applied in order to eliminate the double-heterogeneity of HTGR fuel elements in the deterministic lattice calculations. A full core analysis of the reference simplified HTGR core is performed with DYN3D using macroscopic nodal cross sections provided by HELIOS. The SP3 transport approximation is integrated into the multi-group DYN3D code to take anisotropy of the neutron flux and heterogeneity of the core more precisely into account. The SP3 method was developed for hexagonal geometry of the graphite blocks, where the hexagons are subdivided into triangular nodes. A 3D heat conduction module coupled with a channel-type coolant flow model is implemented into the code. It is shown that there is significant redistribution of the produced heat by heat conduction between the graphite blocks. (orig.)

  5. The Performance Evaluation of Multi-Image 3d Reconstruction Software with Different Sensors

    Mousavi, V.; Khosravi, M.; Ahmadi, M.; Noori, N.; Naveh, A. Hosseini; Varshosaz, M.

    2015-12-01

    Today, multi-image 3D reconstruction is an active research field and generating three dimensional model of the objects is one the most discussed issues in Photogrammetry and Computer Vision that can be accomplished using range-based or image-based methods. Very accurate and dense point clouds generated by range-based methods such as structured light systems and laser scanners has introduced them as reliable tools in the industry. Image-based 3D digitization methodologies offer the option of reconstructing an object by a set of unordered images that depict it from different viewpoints. As their hardware requirements are narrowed down to a digital camera and a computer system, they compose an attractive 3D digitization approach, consequently, although range-based methods are generally very accurate, image-based methods are low-cost and can be easily used by non-professional users. One of the factors affecting the accuracy of the obtained model in image-based methods is the software and algorithm used to generate three dimensional model. These algorithms are provided in the form of commercial software, open source and web-based services. Another important factor in the accuracy of the obtained model is the type of sensor used. Due to availability of mobile sensors to the public, popularity of professional sensors and the advent of stereo sensors, a comparison of these three sensors plays an effective role in evaluating and finding the optimized method to generate three-dimensional models. Lots of research has been accomplished to identify a suitable software and algorithm to achieve an accurate and complete model, however little attention is paid to the type of sensors used and its effects on the quality of the final model. The purpose of this paper is deliberation and the introduction of an appropriate combination of a sensor and software to provide a complete model with the highest accuracy. To do this, different software, used in previous studies, were compared and

  6. THE PERFORMANCE EVALUATION OF MULTI-IMAGE 3D RECONSTRUCTION SOFTWARE WITH DIFFERENT SENSORS

    V. Mousavi

    2015-12-01

    Full Text Available Today, multi-image 3D reconstruction is an active research field and generating three dimensional model of the objects is one the most discussed issues in Photogrammetry and Computer Vision that can be accomplished using range-based or image-based methods. Very accurate and dense point clouds generated by range-based methods such as structured light systems and laser scanners has introduced them as reliable tools in the industry. Image-based 3D digitization methodologies offer the option of reconstructing an object by a set of unordered images that depict it from different viewpoints. As their hardware requirements are narrowed down to a digital camera and a computer system, they compose an attractive 3D digitization approach, consequently, although range-based methods are generally very accurate, image-based methods are low-cost and can be easily used by non-professional users. One of the factors affecting the accuracy of the obtained model in image-based methods is the software and algorithm used to generate three dimensional model. These algorithms are provided in the form of commercial software, open source and web-based services. Another important factor in the accuracy of the obtained model is the type of sensor used. Due to availability of mobile sensors to the public, popularity of professional sensors and the advent of stereo sensors, a comparison of these three sensors plays an effective role in evaluating and finding the optimized method to generate three-dimensional models. Lots of research has been accomplished to identify a suitable software and algorithm to achieve an accurate and complete model, however little attention is paid to the type of sensors used and its effects on the quality of the final model. The purpose of this paper is deliberation and the introduction of an appropriate combination of a sensor and software to provide a complete model with the highest accuracy. To do this, different software, used in previous

  7. Development of a patient-specific 3D dose evaluation program for QA in radiation therapy

    Lee, Suk; Chang, Kyung Hwan; Cao, Yuan Jie; Shim, Jang Bo; Yang, Dae Sik; Park, Young Je; Yoon, Won Sup; Kim, Chul Yong

    2015-03-01

    We present preliminary results for a 3-dimensional dose evaluation software system ( P DRESS, patient-specific 3-dimensional dose real evaluation system). Scanned computed tomography (CT) images obtained by using dosimetry were transferred to the radiation treatment planning system (ECLIPSE, VARIAN, Palo Alto, CA) where the intensity modulated radiation therapy (IMRT) nasopharynx plan was designed. We used a 10 MV photon beam (CLiX, VARIAN, Palo Alto, CA) to deliver the nasopharynx treatment plan. After irradiation, the TENOMAG dosimeter was scanned using a VISTA ™ scanner. The scanned data were reconstructed using VistaRecon software to obtain a 3D dose distribution of the optical density. An optical-CT scanner was used to readout the dose distribution in the gel dosimeter. Moreover, we developed the P DRESS by using Flatform, which were developed by our group, to display the 3D dose distribution by loading the DICOM RT data which are exported from the radiotherapy treatment plan (RTP) and the optical-CT reconstructed VFF file, into the independent P DRESS with an ioniz ation chamber and EBT film was used to compare the dose distribution calculated from the RTP with that measured by using a gel dosimeter. The agreement between the normalized EBT, the gel dosimeter and RTP data was evaluated using both qualitative and quantitative methods, such as the isodose distribution, dose difference, point value, and profile. The profiles showed good agreement between the RTP data and the gel dosimeter data, and the precision of the dose distribution was within ±3%. The results from this study showed significantly discrepancies between the dose distribution calculated from the treatment plan and the dose distribution measured by a TENOMAG gel and by scanning with an optical CT scanner. The 3D dose evaluation software system ( P DRESS, patient specific dose real evaluation system), which were developed in this study evaluates the accuracies of the three-dimensional dose

  8. In Vitro Biological Evaluation of 3-D Hydroxyapatite/Collagen (50/50 wt. (% Scaffolds

    Doris Moura Campos

    2012-02-01

    Full Text Available Hydroxyapatite-collagen (HA/Col composites are potential scaffolds for bone tissue engineering. In this work, three-dimensional (3-D HA/Col (50/50 wt. (% scaffolds were synthesized using a self-assembly method and cross-linked with a 0.125% glutaraldehyde solution. Scaffolds were evaluated in vitro by cytotoxicity testing using MC3T3 cells; proliferation and differentiation were studied using STRO-1A human stromal cells for up to 21 days. Morphological and histological examinations showed a fibrous structure with a good distribution and homogeneous HA particles distribution. By thermogravimetric analysis, a ratio of 1.2 between inorganic and organic phase was found. The scaffolds presented no cytotoxicity when evaluated using three different parameters of cell survival and integrity: 2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl] -2H-tetrazolium-5-carboxanilide (XTT, Neutral Red (NR and Crystal Violet Dye Elution (CVDE. STRO-1A cells were found to adhere, proliferate and differentiate on the 3-D scaffold, but limited cell penetration was observed.

  9. On reliability of 3D reconstructions of thermal plasma jet radiation by inverse Radon transform

    Sekerešová, Zuzana; Hlína, Jan

    2011-01-01

    Roč. 56, č. 2 (2011), s. 171-183. ISSN 0001-7043 Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma jet * tomography * image reconstruction Subject RIV: BL - Plasma and Gas Discharge Physics

  10. 3D COMSOL Simulations for Thermal Deflection of HFIR Fuel Plate in the "Cheverton-Kelley" Experiments

    Jain, Prashant K [ORNL; Freels, James D [ORNL; Cook, David Howard [ORNL

    2012-08-01

    Three dimensional simulation capabilities are currently being developed at Oak Ridge National Laboratory using COMSOL Multiphysics, a finite element modeling software, to investigate thermal expansion of High Flux Isotope Reactor (HFIR) s low enriched uranium fuel plates. To validate simulations, 3D models have also been developed for the experimental setup used by Cheverton and Kelley in 1968 to investigate the buckling and thermal deflections of HFIR s highly enriched uranium fuel plates. Results for several simulations are presented in this report, and comparisons with the experimental data are provided when data are available. A close agreement between the simulation results and experimental findings demonstrates that the COMSOL simulations are able to capture the thermal expansion physics accurately and that COMSOL could be deployed as a predictive tool for more advanced computations at realistic HFIR conditions to study temperature-induced fuel plate deflection behavior.

  11. Design and Performance Evaluation on Ultra-Wideband Time-Of-Arrival 3D Tracking System

    Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Dusl, John

    2012-01-01

    A three-dimensional (3D) Ultra-Wideband (UWB) Time--of-Arrival (TOA) tracking system has been studied at NASA Johnson Space Center (JSC) to provide the tracking capability inside the International Space Station (ISS) modules for various applications. One of applications is to locate and report the location where crew experienced possible high level of carbon-dioxide and felt upset. In order to accurately locate those places in a multipath intensive environment like ISS modules, it requires a robust real-time location system (RTLS) which can provide the required accuracy and update rate. A 3D UWB TOA tracking system with two-way ranging has been proposed and studied. The designed system will be tested in the Wireless Habitat Testbed which simulates the ISS module environment. In this presentation, we discuss the 3D TOA tracking algorithm and the performance evaluation based on different tracking baseline configurations. The simulation results show that two configurations of the tracking baseline are feasible. With 100 picoseconds standard deviation (STD) of TOA estimates, the average tracking error 0.2392 feet (about 7 centimeters) can be achieved for configuration Twisted Rectangle while the average tracking error 0.9183 feet (about 28 centimeters) can be achieved for configuration Slightly-Twisted Top Rectangle . The tracking accuracy can be further improved with the improvement of the STD of TOA estimates. With 10 picoseconds STD of TOA estimates, the average tracking error 0.0239 feet (less than 1 centimeter) can be achieved for configuration "Twisted Rectangle".

  12. Evaluation of feature-based 3-d registration of probabilistic volumetric scenes

    Restrepo, Maria I.; Ulusoy, Ali O.; Mundy, Joseph L.

    2014-12-01

    Automatic estimation of the world surfaces from aerial images has seen much attention and progress in recent years. Among current modeling technologies, probabilistic volumetric models (PVMs) have evolved as an alternative representation that can learn geometry and appearance in a dense and probabilistic manner. Recent progress, in terms of storage and speed, achieved in the area of volumetric modeling, opens the opportunity to develop new frameworks that make use of the PVM to pursue the ultimate goal of creating an entire map of the earth, where one can reason about the semantics and dynamics of the 3-d world. Aligning 3-d models collected at different time-instances constitutes an important step for successful fusion of large spatio-temporal information. This paper evaluates how effectively probabilistic volumetric models can be aligned using robust feature-matching techniques, while considering different scenarios that reflect the kind of variability observed across aerial video collections from different time instances. More precisely, this work investigates variability in terms of discretization, resolution and sampling density, errors in the camera orientation, and changes in illumination and geographic characteristics. All results are given for large-scale, outdoor sites. In order to facilitate the comparison of the registration performance of PVMs to that of other 3-d reconstruction techniques, the registration pipeline is also carried out using Patch-based Multi-View Stereo (PMVS) algorithm. Registration performance is similar for scenes that have favorable geometry and the appearance characteristics necessary for high quality reconstruction. In scenes containing trees, such as a park, or many buildings, such as a city center, registration performance is significantly more accurate when using the PVM.

  13. Neutronic and thermal-hydraulic coupling for 3D reactor core modeling combining MCB and fluent

    Królikowski Igor P.

    2015-09-01

    Full Text Available Three-dimensional simulations of neutronics and thermal hydraulics of nuclear reactors are a tool used to design nuclear reactors. The coupling of MCB and FLUENT is presented, MCB allows to simulate neutronics, whereas FLUENT is computational fluid dynamics (CFD code. The main purpose of the coupling is to exchange data such as temperature and power profile between both codes. Temperature required as an input parameter for neutronics is significant since cross sections of nuclear reactions depend on temperature. Temperature may be calculated in thermal hydraulics, but this analysis needs as an input the power profile, which is a result from neutronic simulations. Exchange of data between both analyses is required to solve this problem. The coupling is a better solution compared to the assumption of estimated values of the temperatures or the power profiles; therefore the coupled analysis was created. This analysis includes single transient neutronic simulation and several steady-state thermal simulations. The power profile is generated in defined points in time during the neutronic simulation for the thermal analysis to calculate temperature. The coupled simulation gives information about thermal behavior of the reactor, nuclear reactions in the core, and the fuel evolution in time. Results show that there is strong influence of neutronics on thermal hydraulics. This impact is stronger than the impact of thermal hydraulics on neutronics. Influence of the coupling on temperature and neutron multiplication factor is presented. The analysis has been performed for the ELECTRA reactor, which is lead-cooled fast reactor concept, where the coolant fl ow is generated only by natural convection

  14. A novel time dependent gamma evaluation function for dynamic 2D and 3D dose distributions

    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

  15. Evaluation of failing hemodialysis fistulas with multidetector CT angiography: Comparison of different 3D planes

    Karadeli, E. [Department of Radiology, Baskent University, Faculty of Medicine, Ankara (Turkey); Tarhan, N.C. [Department of Radiology, Baskent University, Faculty of Medicine, Ankara (Turkey)], E-mail: caglat@baskent-ank.edu.tr; Ulu, E.M. Kayahan; Tutar, N.U. [Department of Radiology, Baskent University, Faculty of Medicine, Ankara (Turkey); Basaran, O. [Department of General Surgery, Baskent University, Faculty of Medicine, Ankara (Turkey); Coskun, M.; Niron, E.A. [Department of Radiology, Baskent University, Faculty of Medicine, Ankara (Turkey)

    2009-01-15

    Purpose: To evaluate failing hemodialysis fistula complications using 16-detector MDCTA, and to assess the accuracies of different 3D planes. Materials and methods: Thirty patients (16 men, 14 women, aged 27-79 years) were referred for hemodialysis access dysfunction. Thirty-one MDCTA exams were done prior to fistulography. For MDCTA, contrast was administered (2 mL/kg at 5 mL/s) via a peripheral vein in the contralateral arm. Axial MIP, coronal MIP, and VRT images were constructed. Venous complications were evaluated on axial source images, on each 3D plane, and on all-planes together. Results were analyzed using McNemar test. Results: Axial MIP, VRT and all-planes evaluations were most sensitive for fistula site detection (93%). Coronal MIP had the highest sensitivity, specificity and accuracy (35%, 96%, and 85%, respectively) for detecting venous stenosis. VRT and all-planes had the highest sensitivity and accuracy for detecting aneurysms (100%). All-planes and axial MIP were most sensitive for detecting venous occlusion (61% and 54%). Comparisons of detection frequencies for each venous pathology between the five categories of MDCTA revealed no significant differences (P > 0.05). MDCTA additionally showed 3 partially thrombosed aneurysms, 4 anastomosis site stenosis and 12 arterial complications. Conclusion: MDCTA overall gives low sensitivity for detection of central vein stenosis and moderate sensitivity for occlusion. For most pathology, all-planes evaluation of MDCTA gives highest sensitivity and accuracy rates when compared to other planes. For venous stenosis and occlusion, MDCTA should be considered when ultrasonography and fistulography are inconclusive. MDCTA is helpful in identifying aneurysms, collaterals, partial venous thromboses and additional arterial, anastomosis site pathologies.

  16. Can 3D ultrasound identify trochlea dysplasia in newborns? Evaluation and applicability of a technique

    Highlights: • We evaluated a possible screening method for trochlea dysplasia. • 3D ultrasound was used to perform the measurements on standardized axial planes. • The evaluation of the technique showed comparable results to other studies. • This technique may be used as a screening technique as it is quick and easy to perform. - Abstract: Femoro-patellar dysplasia is considered as a significant risk factor of patellar instability. Different studies suggest that the shape of the trochlea is already developed in early childhood. Therefore early identification of a dysplastic configuration might be relevant information for the treating physician. An easy applicable routine screening of the trochlea is yet not available. The purpose of this study was to establish and evaluate a screening method for femoro-patellar dysplasia using 3D ultrasound. From 2012 to 2013 we prospectively imaged 160 consecutive femoro-patellar joints in 80 newborns from the 36th to 61st gestational week that underwent a routine hip sonography (Graf). All ultrasounds were performed by a pediatric radiologist with only minimal additional time to the routine hip ultrasound. In 30° flexion of the knee, axial, coronal, and sagittal reformats were used to standardize a reconstructed axial plane through the femoral condyle and the mid-patella. The sulcus angle, the lateral-to-medial facet ratio of the trochlea and the shape of the patella (Wiberg Classification) were evaluated. In all examinations reconstruction of the standardized axial plane was achieved, the mean trochlea angle was 149.1° (SD 4.9°), the lateral-to-medial facet ratio of the trochlea ratio was 1.3 (SD 0.22), and a Wiberg type I patella was found in 95% of the newborn. No statistical difference was detected between boys and girls. Using standardized reconstructions of the axial plane allows measurements to be made with lower operator dependency and higher accuracy in a short time. Therefore 3D ultrasound is an easy

  17. Can 3D ultrasound identify trochlea dysplasia in newborns? Evaluation and applicability of a technique

    Kohlhof, Hendrik, E-mail: Hendrik.Kohlhof@ukb.uni-bonn.de [Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn (Germany); Heidt, Christoph, E-mail: Christoph.heidt@kispi.uzh.ch [Department of Orthopedic Surgery, University Children' s Hospital Zurich, Steinwiesstrasse 74, 8032 Switzerland (Switzerland); Bähler, Alexandrine, E-mail: Alexandrine.baehler@insel.ch [Department of Pediatric Radiology, University Children' s Hospital Berne, Freiburgstrasse 18, 3010 Berne (Switzerland); Kohl, Sandro, E-mail: sandro.kohl@insel.ch [Department of Orthopedic Surgery, University Hospital Berne, Freiburgstrasse 18, 3010 Berne (Switzerland); Gravius, Sascha, E-mail: sascha.gravius@ukb.uni-bonn.de [Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn (Germany); Friedrich, Max J., E-mail: Max.Friedrich@ukb.uni-bonn.de [Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Sigmund-Freud-Str. 25, 53127 Bonn (Germany); Ziebarth, Kai, E-mail: kai.ziebarth@insel.ch [Department of Orthopedic Surgery, University Hospital Berne, Freiburgstrasse 18, 3010 Berne (Switzerland); Stranzinger, Enno, E-mail: Enno.Stranzinger@insel.ch [Department of Pediatric Radiology, University Children' s Hospital Berne, Freiburgstrasse 18, 3010 Berne (Switzerland)

    2015-06-15

    Highlights: • We evaluated a possible screening method for trochlea dysplasia. • 3D ultrasound was used to perform the measurements on standardized axial planes. • The evaluation of the technique showed comparable results to other studies. • This technique may be used as a screening technique as it is quick and easy to perform. - Abstract: Femoro-patellar dysplasia is considered as a significant risk factor of patellar instability. Different studies suggest that the shape of the trochlea is already developed in early childhood. Therefore early identification of a dysplastic configuration might be relevant information for the treating physician. An easy applicable routine screening of the trochlea is yet not available. The purpose of this study was to establish and evaluate a screening method for femoro-patellar dysplasia using 3D ultrasound. From 2012 to 2013 we prospectively imaged 160 consecutive femoro-patellar joints in 80 newborns from the 36th to 61st gestational week that underwent a routine hip sonography (Graf). All ultrasounds were performed by a pediatric radiologist with only minimal additional time to the routine hip ultrasound. In 30° flexion of the knee, axial, coronal, and sagittal reformats were used to standardize a reconstructed axial plane through the femoral condyle and the mid-patella. The sulcus angle, the lateral-to-medial facet ratio of the trochlea and the shape of the patella (Wiberg Classification) were evaluated. In all examinations reconstruction of the standardized axial plane was achieved, the mean trochlea angle was 149.1° (SD 4.9°), the lateral-to-medial facet ratio of the trochlea ratio was 1.3 (SD 0.22), and a Wiberg type I patella was found in 95% of the newborn. No statistical difference was detected between boys and girls. Using standardized reconstructions of the axial plane allows measurements to be made with lower operator dependency and higher accuracy in a short time. Therefore 3D ultrasound is an easy

  18. RFX first wall thermal power handling: 3D numerical models and experimental validations

    One of the emerging issues for future thermonuclear devices is the non-uniform power deposition on the first wall or divertor surfaces. The localized peaks of power are detrimental both for the lifetime of the plasma facing components and for plasma heating and confinement. The thermal monitoring of the first wall can be done with temperature measurements acquired during the experiments by means of thermocouples and/or infrared camera images. If the measurement system is integrated with analytical or numerical models, it is possible to estimate the applied thermal loads and to obtain a thorough knowledge of the thermal behaviour of the first wall and vacuum vessel system. The numerical model developed for the RFX machine is hereby described and validated by means of comparisons with IR camera and thermocouple temperature measurements

  19. Two-photon luminescence thermometry: towards 3D high-resolution thermal imaging of waveguides.

    He, Ruiyun; Vázquez de Aldana, Javier Rodríguez; Pedrola, Ginés Lifante; Chen, Feng; Jaque, Daniel

    2016-07-11

    We report on the use of the Erbium-based luminescence thermometry to realize high resolution, three dimensional thermal imaging of optical waveguides. Proof of concept is demonstrated in a 980-nm laser pumped ultrafast laser inscribed waveguide in Er:Yb phosphate glass. Multi-photon microscopy images revealed the existence of well confined intra-waveguide temperature increments as large as 200 °C for moderate 980-nm pump powers of 120 mW. Numerical simulations and experimental data reveal that thermal loading can be substantially reduced if pump events are separated more than the characteristic thermal time that for the waveguides investigated is in the ms time scale. PMID:27410882

  20. TMI-1 MSLB coupled 3-D neutronics/thermal hydraulics analysis: application of RELAP5-3D and comparison with different codes

    A comprehensive analysis of the double ended Main Steam Line Break (MSLB) accident assumed to occur in the Babcock and Wilcox nuclear power plant of Three Miles Island Unit 1 (TMI-1) has been carried out of the University of Pisa in co-operation with the University of Zagreb and the Texas A and M University. The overall activity has been completed within the framework of the participation in the OECD-CSNI/NSC (Committee on the Safety of Nuclear Installations - Nuclear Science Committee) 'PWR MSLB Benchmark'. Different code versions have been adopted in the analysis. Results from the following codes (or code versions) are described in this paper: RELAP5/MOD3.2.2, beta version, coupled with the 3-D neutron kinetics Parcs code; RELAP5/MOD3.2.2, gamma version, coupled with the 3-D neutron kinetics Quabbox code; RELAP5/3D, coupled with the 3-D neutron kinetics Nestle code. Boundary and initial conditions of the system including those relevant to the fuel status, have been supplied by Pensilvania State University that had a co-operation GPU (the utility, owner of TMI) and NRC (US Nuclear Regulatory Commission). The capability of the control rods to recover the accident has been demonstrated in all the cases as well as the capability of all the codes to predict the time evolution of the assigned transient. However, one stuck control rod caused some 're-criticality' or 'return-to-power' whose magnitude is largely affected by boundary and initial conditions. The comparison among the results obtained by adopting the same thermalhydraulic nodalization and the different 'coupled' code version is discussed in the present document. (author)

  1. The time-dependent 3D discrete ordinates code TORT-TD with thermal-hydraulic feedback by ATHLET models

    This paper describes the time-dependent 3D discrete ordinates transport code TORT-TD. Thermal-hydraulic feedback is considered by coupling TORT-TD with the thermal-hydraulics system code ATHLET. The coupled code TORT-TD/ATHLET allows 3D pin-by-pin analyses of transients in few energy groups and anisotropic scattering by solving the time-dependent transport equation using the unconditionally stable implicit method. The nuclear cross sections are interpolated between pre-calculated table values of fuel temperature, moderator density and boron concentration. For verification of the implementation, selected test cases have been calculated by TORT-TD/ATHLET. They include a control rod ejection transient in a small PWR fuel assembly arrangement and a local boron concentration change in a single PWR fuel assembly. In the latter, special attention has been paid to study the influence of the thermal-hydraulic feedback modelling in ATHLET. The results obtained for a control rod ejection accident in a PWR quarter core demonstrate the applicability of TORT-TD/ATHLET. (authors)

  2. The time-dependent 3D discrete ordinates code TORT-TD with thermal-hydraulic feedback by ATHLET models

    Seubert, A.; Velkov, K.; Langenbuch, S. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Forschungsinstitute, D-85748 Garching (Germany)

    2008-07-01

    This paper describes the time-dependent 3D discrete ordinates transport code TORT-TD. Thermal-hydraulic feedback is considered by coupling TORT-TD with the thermal-hydraulics system code ATHLET. The coupled code TORT-TD/ATHLET allows 3D pin-by-pin analyses of transients in few energy groups and anisotropic scattering by solving the time-dependent transport equation using the unconditionally stable implicit method. The nuclear cross sections are interpolated between pre-calculated table values of fuel temperature, moderator density and boron concentration. For verification of the implementation, selected test cases have been calculated by TORT-TD/ATHLET. They include a control rod ejection transient in a small PWR fuel assembly arrangement and a local boron concentration change in a single PWR fuel assembly. In the latter, special attention has been paid to study the influence of the thermal-hydraulic feedback modelling in ATHLET. The results obtained for a control rod ejection accident in a PWR quarter core demonstrate the applicability of TORT-TD/ATHLET. (authors)

  3. Development of NSSS Thermal-Hydraulic Model for KNPEC-2 Simulator Using the Best-Estimate Code RETRAN-3D

    The Nuclear Steam Supply System (NSSS) thermal-hydraulic model adopted in the Korea Nuclear Plant Education Center (KNPEC)-2 simulator was provided in the early 1980s. The reference plant for KNPEC-2 is the Yong Gwang Nuclear Unit 1, which is a Westinghouse-type 3-loop, 950 MW(electric) pressurized water reactor. Because of the limited computational capability at that time, it uses overly simplified physical models and assumptions for a real-time simulation of NSSS thermal-hydraulic transients. This may entail inaccurate results and thus, the possibility of so-called ''negative training,'' especially for complicated two-phase flows in the reactor coolant system. To resolve the problem, we developed a realistic NSSS thermal-hydraulic program (named ARTS code) based on the best-estimate code RETRAN-3D. The systematic assessment of ARTS has been conducted by both a stand-alone test and an integrated test in the simulator environment. The non-integrated stand-alone test (NIST) results were reasonable in terms of accuracy, real-time simulation capability, and robustness. After successful completion of the NIST, ARTS was integrated with a 3-D reactor kinetics model and other system models. The site acceptance test (SAT) has been completed successively and confirmed to comply with the ANSI/ANS-3.5-1998 simulator software performance criteria. This paper presents our efforts for the ARTS development and some test results of the NIST and SAT

  4. Evaluation and application of 3D lung warping and registration model using HRCT images

    Fan, Li; Chen, Chang W.; Reinhardt, Joseph M.; Hoffman, Eric A.

    2001-05-01

    Image-based study of structure-function relationships is a challenging problem in that the structure or region of interest may vary in position and shape on images captured over time. Such variation may be caused by the change in body posture or the motion of breathing and heart beating. Therefore, the structure or region of interest should be registered before any further regional study can be carried out. In this paper, we propose a novel approach to study the structure-function relationship of ventilation using a previously developed 3D lung warping and registration model. First, we evaluate the effectiveness of the lung warping and registration model using a set of criteria, including apparent lung motion patterns and ground truths. Then, we study the ventilation by integrating the warping model with air content calibration. The warping model is applied to three CT lung data sets, obtained under volume control of FRC, 40% and 75% vital capacity (VC). Dense displacement fields are obtained to represent deformation between different lung volume steps. For any specific region of interest, we first register it between images over time using the dense displacement, and then estimate the corresponding regional inspired air content. Assessments include change of regional volume during inspiration, change of regional air content, and the distribution of regional ventilation. This is the first time that 3D warping of lung images is applied to assess clinically significant pulmonary functions.

  5. AN EXPERIMENTAL EVALUATION OF 3D TERRAIN MAPPING WITH AN AUTONOMOUS HELICOPTER

    B. P. Hudzietz

    2012-09-01

    Full Text Available We demonstrate a method for unmanned aerial vehicle based structure from motion mapping and show it to be a viable option for large scale, high resolution terrain modeling. Current methods of large scale terrain modeling can be cost and time prohibitive. We present a method for integrating low cost cameras and unmanned aerial vehicles for the purpose of 3D terrain mapping. Using structure from motion, aerial images taken of the landscape can be reconstructed into 3D models of the terrain. This process is well suited for use on unmanned aerial vehicles due to the light weight and low cost of equipment. We discuss issues of flight path planning and propose an algorithm to assist in the generation of these paths. The structure from motion mapping process is experimentally evaluated in three distinct environments: ground based testing on man-made environments, ground based testing on natural environments, and airborne testing on natural environments. Ground based testing on natural environments was shown to be extremely useful for camera calibration, and the resulting models were found to have a maximum error of 4.26 cm and standard deviation of 1.50 cm. During airborne testing, several areas of approximately 30,000 m2 were mapped. These areas were mapped with acceptable accuracy and a resolution of 1.24 cm.

  6. Thermal Resistance across Interfaces Comprising Dimensionally Mismatched Carbon Nanotube-Graphene Junctions in 3D Carbon Nanomaterials

    Jungkyu Park

    2014-01-01

    Full Text Available In the present study, reverse nonequilibrium molecular dynamics is employed to study thermal resistance across interfaces comprising dimensionally mismatched junctions of single layer graphene floors with (6,6 single-walled carbon nanotube (SWCNT pillars in 3D carbon nanomaterials. Results obtained from unit cell analysis indicate the presence of notable interfacial thermal resistance in the out-of-plane direction (along the longitudinal axis of the SWCNTs but negligible resistance in the in-plane direction along the graphene floor. The interfacial thermal resistance in the out-of-plane direction is understood to be due to the change in dimensionality as well as phonon spectra mismatch as the phonons propagate from SWCNTs to the graphene sheet and then back again to the SWCNTs. The thermal conductivity of the unit cells was observed to increase nearly linearly with an increase in cell size, that is, pillar height as well as interpillar distance, and approaches a plateau as the pillar height and the interpillar distance approach the critical lengths for ballistic thermal transport in SWCNT and single layer graphene. The results indicate that the thermal transport characteristics of these SWCNT-graphene hybrid structures can be tuned by controlling the SWCNT-graphene junction characteristics as well as the unit cell dimensions.

  7. Analysis of Thermal Plasma Dynamics in 3-D Using Tomographical Reconstruction and Wavelet Analysis

    Gruber, Jan; Sekerešová, Zuzana; Hlína, Jan; Šonský, Jiří

    2011-01-01

    Roč. 39, č. 11 (2011), s. 2850-2851. ISSN 0093-3813 Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma * tomography * wavelets Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.174, year: 2011 http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5783941

  8. 3D Reconstruction of Thermal Plasma Jet Radiation by Inverse Radon Transformation

    Sekerešová, Zuzana; Hlína, Jan; Šonský, Jiří

    Greifswald : Leibniz Institute, 2010, s. 552-555. ISBN 0-9539105-4-7. [International Conference on Gas Discharges and their Applications /18./. Greifswald (DE), 05.09.2010-10.09.2010] Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma * inverse Radon transformation * three-dimensional reconstruction Subject RIV: BL - Plasma and Gas Discharge Physics

  9. Implementation of an Acoustic 3D BEM with Visco-Thermal Losses

    Cutanda Henriquez, Vicente; Juhl, Peter Møller

    2013-01-01

    . In the present work, a three-dimensional BEM implementation based on the Kirchhoff decomposition of the Navier-Stokes equations into viscous, thermal and acoustic wave modes is described. The implementation details include: i) development of a vector velocity boundary condition and the coordinate...

  10. Atmospheric correction of thermal-infrared imagery of the 3-D urban environment acquired in oblique viewing geometry

    F. Meier; D. Scherer; Richters, J.; A. Christen

    2011-01-01

    This research quantifies and discusses atmospheric effects, which alter the radiance observed by a ground-based thermal-infrared (TIR) camera. The TIR camera is mounted on a boom at a height of 125 m above ground on top of a high-rise building in the city of Berlin, Germany (52.4556° N, 13.3200° E) and observes the Earth's surface. The study shows that atmospheric correction of TIR imagery of the three-dimensional (3-D) urban environment acquired in oblique viewing geometry has to account for...

  11. 3-D numerical simulation of Yb:YAG active slabs with longitudinal doping gradient for thermal load effects assessment.

    Ferrara, P; Ciofini, M; Esposito, L; Hostaša, J; Labate, L; Lapucci, A; Pirri, A; Toci, G; Vannini, M; Gizzi, L A

    2014-03-10

    We present a study of Yb:YAG active media slabs, based on a ceramic layered structure with different doping levels. We developed a procedure allowing 3D numerical analysis of the slab optical properties as a consequence of the thermal load induced by the pump process. The simulations are compared with a set of experimental results in order to validate the procedure. These structured ceramics appear promising in appropriate geometrical configurations, and thus are intended to be applied in the construction of High Energy Diode Pumped Solid State Laser (DPSSL) systems working in high repetition-rate pulsed regimes. PMID:24663877

  12. Transient analysis in the 3D nodal kinetics and thermal-hydraulics ANDES/COBRA coupled system

    Lozano Montero, Juan Andrés; Aragonés Beltrán, José María; García Herranz, Nuria

    2008-01-01

    Neutron kinetics has been implemented in the 3D nodal solver ANDES, which has been coupled to the core thermal-hydraulics (TH) code COBRA-III for core transient analysis. The purpose of this work is, first, to discuss and test the ability of the kinetics solver ANDES to model transients; and second, by means of a systematic analysis, including alternate kinetics schemes, time step size, nodal size, neutron energy groups and spectrum, to serve as a basis for the development of more accurate an...

  13. Spice Thermal Subcircuit of Multifinger HBT derived from Ritz Vector reduction technique of 3D Thermal Simulation for electrothermal modeling

    Lopez, D.; Sommet, R.; Quéré, R.

    2001-01-01

    This paper deals with the integration of a reduced thermal model based on tree dimensional Finite Element (FE) thermal simulation into circuit simulator for accurate prediction of electrothermal behavior of power devices. The reduced thermal model based on the Ritz vectors approach is easily usable in any kind of circuit simulator because it is described by a spice format subcircuit. The model has been successfully experimented with the ADS simulator. Electrical based thermal measurements of ...

  14. Quantitative evaluation of 3D dosimetry for stereotactic volumetric-modulated arc delivery using COMPASS.

    Vikraman, Subramani; Manigandan, Durai; Karrthick, Karukkupalayam Palaniappan; Sambasivaselli, Raju; Senniandavar, Vellaingiri; Ramu, Mahendran; Rajesh, Thiyagarajan; Lutz, Muller; Muthukumaran, Manavalan; Karthikeyan, Nithyanantham; Tejinder, Kataria

    2015-01-01

    The purpose of this study was to evaluate quantitatively the patient-specific 3D dosimetry tool COMPASS with 2D array MatriXX detector for stereotactic volumetric-modulated arc delivery. Twenty-five patients CT images and RT structures from different sites (brain, head & neck, thorax, abdomen, and spine) were taken from CyberKnife Multiplan planning system for this study. All these patients underwent radical stereotactic treatment in CyberKnife. For each patient, linac based volumetric-modulated arc therapy (VMAT) stereotactic plans were generated in Monaco TPS v3.1 using Elekta Beam Modulator MLC. Dose prescription was in the range of 5-20 Gy per fraction. Target prescription and critical organ constraints were tried to match the delivered treatment plans. Each plan quality was analyzed using conformity index (CI), conformity number (CN), gradient Index (GI), target coverage (TC), and dose to 95% of volume (D95). Monaco Monte Carlo (MC)-calculated treatment plan delivery accuracy was quantitatively evaluated with COMPASS-calculated (CCA) dose and COMPASS indirectly measured (CME) dose based on dose-volume histogram metrics. In order to ascertain the potential of COMPASS 3D dosimetry for stereotactic plan delivery, 2D fluence verification was performed with MatriXX using MultiCube phantom. Routine quality assurance of absolute point dose verification was performed to check the overall delivery accuracy. Quantitative analyses of dose delivery verification were compared with pass and fail criteria of 3 mm and 3% distance to agreement and dose differences. Gamma passing rate was compared with 2D fluence verification from MatriXX with MultiCube. Comparison of COMPASS reconstructed dose from measured fluence and COMPASS computed dose has shown a very good agreement with TPS calculated dose. Each plan was evaluated based on dose volume parameters for target volumes such as dose at 95% of volume (D95) and average dose. For critical organs dose at 20% of volume (D20), dose

  15. Numerical simulation of the 3D behavior of thermal buoyant airflows in pentahedral spaces

    Ridouane, El Hassan [Department of Mechanical Engineering, University of Vermont, 33 Colchester Avenue, 201 Votey Building, Burlington, VT 05405 (United States)], E-mail: eridouan@uvm.edu; Campo, Antonio [Department of Mechanical Engineering, University of Vermont, 33 Colchester Avenue, 201 Votey Building, Burlington, VT 05405 (United States)

    2008-10-15

    A numerical study of three-dimensional natural convection in an attic space with heated horizontal base and cooled upper walls is presented. Every previous study pertinent to this subject as of today has assumed that the flow in attics is two-dimensional and restricted to triangular cavities. This problem is examined for fixed aspect ratios holding width to height of 2 and depth to height of 3.33 and Rayleigh numbers ranging from 10{sup 4} to 8 x 10{sup 5}. The coupled system of conservation equations, subject to the proper boundary conditions, along with the equation of state assuming the air behaves as a perfect gas are solved with the finite volume method. In the conservation equations, the second-order-accurate QUICK scheme was used for the discretization of the convective terms and the SIMPLE scheme for the pressure-velocity coupling. It is categorically found that the flow in the attic is 3D. From the physics of the problem, two steady-state solutions are possible. The symmetrical solution prevails for relatively low Rayleigh numbers. However, as the Ra is gradually increased, a transition occurs at a critical value Ra{sub C}. Above this value of Ra{sub C}, an asymmetrical solution exhibiting a pitchfork bifurcation arises and eventually becomes steady. Results are presented detailing the occurrence of the pitchfork bifurcation and the resulting flow patterns are described.

  16. A Numerical Study on the Thermal Conductivity of 3D Woven C/C Composites at High Temperature

    Shigang, Ai; Rujie, He; Yongmao, Pei

    2015-12-01

    Experimental data for Carbon/Carbon (C/C) constituent materials are combined with a three dimensional steady state heat transfer finite element analysis to demonstrate the average in-plane and out-of-plane thermal conductivities (TCs) of C/C composites. The finite element analysis is carried out at two distinct length scales: (a) a micro scale comparable with the diameter of carbon fibres and (b) a meso scale comparable with the carbon fibre yarns. Micro-scale model calculate the TCs at the fibre yarn scale in the three orthogonal directions ( x, y and z). The output results from the micro-scale model are then incorporated in the meso-scale model to obtain the global TCs of the 3D C/C composite. The simulation results are quite consistent with the theoretical and experimental counterparts reported in references. Based on the numerical approach, TCs of the 3D C/C composite are calculated from 300 to 2500 K. Particular attention is given in elucidating the variations of the TCs with temperature. The multi-scale models provide an efficient approach to predict the TCs of 3D textile materials, which is helpful for the thermodynamic property analysis and structure design of the C/C composites.

  17. Thermal Conductivity of 3D CNT-Polymer Composites with Controlled Dispersion

    Klittich, Mena; Wang, Xue; Dhinojwala, Ali

    The high thermal conductivity of isolated carbon nanotubes (CNTs) has inspired its use as a thermal filler for insulative polymers. However, the performance of these composites has consistently been sub par. Extensive analyses of these complex systems have resulted in the conclusion that resistance at the CNT/polymer interface due to phonon mismatch and poor physical binding, as well as the weakly bonded tube-tube interactions restrict the effectiveness of CNTs in practice. Experimental comparisons of CNT treatments, coatings, functionalization, and interactions with various polymers have proved challenging, due to the interconnected nature of the composite properties. Here, we have reversed the paradigm and used a constant CNT structure that is then modified post-growth to allow for direct comparisons of polymer composites.

  18. GeoFlow: 3D numerical simulation of supercritical thermal convective states

    Futterer, B; Egbers, C [Department of Aerodynamics and Fluid Mechanics, Brandenburg University of Technology Cottbus, Siemens-Halske-Ring 14, 03046 Cottbus (Germany); Hollerbach, R [Department of Applied Mathematics, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT (United Kingdom)], E-mail: futterer@tu-cottbus.de

    2008-11-01

    'GeoFlow' is a thermal convection experiment in rotating spherical shell geometry, which is going to take place in microgravity environment of International Space Station. We present numerical preliminary studies of the spherical Rayleigh-Benard problem under an artificial central force field. Numerical simulation is done with a pseudospectral method. Special focus here is the simulation of flow states at selected parameter points of Rayleigh and Taylor number of a defined plan for experimental runs on ISS. One loop will contain thermal convection without rotation, i.e. rising temperature gradient between inner and outer sphere. Another loop investigates convection superimposed by rotation, i.e. fixing temperature gradient and then rising rotation rate. In such cases different transitions are expected to be observed. Just rising Rayleigh number shows different stable states depending on initial conditions. Fixing Rayleigh number and then rising up Taylor number leads to traverse of different convective states showing rich dynamics of the system.

  19. 3D modeling and simulation of the thermal performance of solid cyclotron targets

    Avila-Rodriguez, M.A.; Sader, J.A.; McQuarrie, S.A. [Alberta Univ., Edmonton PET Centre, Cross Cancer Institute, AB (Canada); McQuarrie, S.A. [Alberta Univ., Faculty of Medicine and Dentistry, Div. of Oncologic Imaging, Edmonton, AB (Canada)

    2007-07-01

    COMSOL Multiphysics was used to model and simulate the thermal performance of solid targets irradiated with charged particles. Parametric solutions for beam power densities in the range from 1.5 10{sup 5} to 1.5 10{sup 6} W/m{sup 2} and cooling water flow velocities from 0.2 to 4.0 m/s were obtained for different plate materials. Results showed that materials with a high thermal conductivity to heat capacity ratio behave better in cooling dynamic systems requiring fast dissipation of heat. Results also showed that water flow rates greater than 2.6 L/min do not noticeably improve the heat dissipation of solid targets irradiated with charged particles. (authors)

  20. Full 3-D numerical modeling of borehole electric image logging and the evaluation model of fracture

    2008-01-01

    A full 3-D finite element method numerical modeling program is written based on the principle and technical specification of borehole electric image well logging tool. The response of well logging is computed in the formation media model with a single fracture. The effect of changing fracture aperture and resistivity ratio to the logging response is discussed. The identification ability for two parallel fractures is also present. A quantitative evaluation formula of fracture aperture from borehole electric image logging data is set up. A case study of the model well is done to verify the accuracy of the for-mula. The result indicates that the formula is more accurate than the foreign one.

  1. Comparative evaluation of scatter correction techniques in 3D positron emission tomography

    Zaidi, H

    2000-01-01

    Much research and development has been concentrated on the scatter compensation required for quantitative 3D PET. Increasingly sophisticated scatter correction procedures are under investigation, particularly those based on accurate scatter models, and iterative reconstruction-based scatter compensation approaches. The main difference among the correction methods is the way in which the scatter component in the selected energy window is estimated. Monte Carlo methods give further insight and might in themselves offer a possible correction procedure. Methods: Five scatter correction methods are compared in this paper where applicable. The dual-energy window (DEW) technique, the convolution-subtraction (CVS) method, two variants of the Monte Carlo-based scatter correction technique (MCBSC1 and MCBSC2) and our newly developed statistical reconstruction-based scatter correction (SRBSC) method. These scatter correction techniques are evaluated using Monte Carlo simulation studies, experimental phantom measurements...

  2. A 3-D thermal regime model suitable for cold accumulation zones of polythermal mountain glaciers

    Gilbert, A.; Gagliardini, O.; Vincent, C.; Wagnon, P.

    2014-09-01

    Analysis of the thermal and mechanical response of high altitude glaciers to climate change is crucial to assess future glacier hazards associated with thermal regime changes. This paper presents a new fully thermo-mechanically coupled transient thermal regime model including enthalpy transport, firn densification, full-Stokes porous flow, free surface evolution, strain heating, surface meltwater percolation, and refreezing. The model is forced by daily air temperature data and can therefore be used to perform prognostic simulations for different future climate scenarios. The set of equations is solved using the finite element ice sheet/ice flow model Elmer/Ice. This model is applied to the Col du Dôme glacier (Mont Blanc area, 4250 m a.s.l., France) where a comprehensive data set is available. The results show that the model is capable of reproducing observed density and velocity fields as well as borehole temperature evolution. The strong spatial variability of englacial temperature change observed at Col du Dôme is well reproduced. This spatial variability is mainly a result of the variability of the slope aspect of the glacier surface and snow accumulation. Results support the use of this model to study the influence of climate change on cold accumulation zones, in particular to estimate where and under what conditions glaciers will become temperate in the future.

  3. Plaque characterization in ex vivo MRI evaluated by dense 3D correspondence with histology

    van Engelen, Arna; de Bruijne, Marleen; Klein, Stefan; Verhagen, Hence; Groen, Harald; Wentzel, Jolanda; van der Lugt, Aad; Niessen, Wiro

    2011-03-01

    Automatic quantification of carotid artery plaque composition is important in the development of methods that distinguish vulnerable from stable plaques. MRI has shown to be capable of imaging different components noninvasively. We present a new plaque classification method which uses 3D registration of histology data with ex vivo MRI data, using non-rigid registration, both for training and evaluation. This is more objective than previously presented methods, as it eliminates selection bias that is introduced when 2D MRI slices are manually matched to histological slices before evaluation. Histological slices of human atherosclerotic plaques were manually segmented into necrotic core, fibrous tissue and calcification. Classification of these three components was voxelwise evaluated. As features the intensity, gradient magnitude and Laplacian in four MRI sequences after different degrees of Gaussian smoothing, and the distances to the lumen and the outer vessel wall, were used. Performance of linear and quadratic discriminant classifiers for different combinations of features was evaluated. Best accuracy (72.5 +/- 7.7%) was reached with the linear classifier when all features were used. Although this was only a minor improvement to the accuracy of a classifier that only included the intensities and distance features (71.6 +/- 7.9%), the difference was statistically significant (paired t-test, p<0.05). Good sensitivity and specificity for calcification was reached (83% and 95% respectively), however, differentiation between fibrous (sensitivity 85%, specificity 60%) and necrotic tissue (sensitivity 49%, specificity 89%) was more difficult.

  4. A Novel Methodology for Thermal Aware Silicon Area Estimation for 2D & 3D MPSoCs

    Vinod Pangracious

    2012-01-01

    Full Text Available In a multiprocessor system on chip (MPSoC IC the processor is one of the highest heat dissipating devices. The temperature generated in an IC may vary with floor plan of the chip. This paper proposes an integration and thermal analysis methodology to extract the peak temperature and temperature distribution of 2-dimensional and 3-dimensional multiprocessor system-on-chip. As we know the peak temperature of chip increases in 3-dimensional structures compared to 2-dimensional ones due to the reduced space in intra-layer and inter-layer components. In sub-nanometre scale technologies, it is inevitable to analysis the heat developed in individual chip to extract the temperature distribution of the entire chip. With thetechnology scaling in new generation ICs more and more components are integrated to a smaller area. Along with the other parameters threshold voltage is also scaled down which results in exponential increase in leakage current. This has resulted in rise in hotspot temperature value due to increase inleakage power. In this paper, we have analysed the temperature developed in an IC with four identical processors at 2.4 GHz in different floorplans. The analysis has been done for both 2D and 3D arrangements. In the 3D arrangement, a three layered structure has been considered with two Silicon layers and a thermal interface material (TIM in between them. Based on experimental results the paperproposes a methodology to reduce the peak temperature developed in 2D and 3D integrated circuits .

  5. A Novel Methodology for Thermal Aware Silicon Area Estimation for 2D & 3D MPSoCs

    Ramya Menon C

    2011-12-01

    Full Text Available In a multiprocessor system on chip (MPSoC IC the processor is one of the highest heat dissipating devices. The temperature generated in an IC may vary with floor plan of the chip. This paper proposes an integration and thermal analysis methodology to extract the peak temperature and temperature distribution of 2-dimensional and 3-dimensional multiprocessor system-on-chip. As we know the peak temperature of chip increases in 3-dimensional structures compared to 2-dimensional ones due to the reduced space in intra-layer and inter-layer components. In sub-nanometre scale technologies, it is inevitable to analysis the heat developed in individual chip to extract the temperature distribution of the entire chip. With the technology scaling in new generation ICs more and more components are integrated to a smaller area. Along with the other parameters threshold voltage is also scaled down which results in exponential increase in leakage current. This has resulted in rise in hot spot temperature value due to increase in leakage power. In this paper, we have analysed the temperature developed in an IC with four identical processors at 2.4 GHz in different floor plans. The analysis has been done for both 2D and 3D arrangements. In the 3D arrangement, a three layered structure has been considered with two Silicon layers and a thermal interface material (TIM in between them. Based on experimental results the paper proposes a methodology to reduce the peak temperature developed in 2D and 3D integrated circuits .

  6. Verification of an Acoustic 3D BEM with Visco-Thermal Losses

    Juhl, Peter Møller; Cutanda Henriquez, Vicente

    2013-01-01

    Sound waves propagating in the interior of devices such as acoustic transducers, hearing aids and mobile phones undergo a significant amount of losses due to viscous and thermal effects. In some cases like microphones, the performance of the device even relies on controlling these loss mechanisms...... cases. These devices are challenging due to the high degree of coupling between diaphragm, internal gap, back cavity and external medium. In this work they are modeled using a coupled FEM-BEM model, where the Finite Element Method is used on the diaphragm....

  7. 3D transient thermal modelling of laser microchannel fabrication in lime-soda glass

    Issa, Ahmad,; Brabazon, Dermot; Hashmi, Saleem

    2008-01-01

    Laser-fabricated microchannels in glass offer a wide range of bioengineering and telecommunication applications. A 1.5 kW CO2 laser with 10.6 μm wavelength was used in this study to fabricate micorchannels on the surface of soda-lime glass sheets. A thermal model of the process was developed based on transient heat conduction due to a pulsed heat input. The resulting equation predicted the temperature distribution in the regions surrounding the laser focus. Temperature – time curves were draw...

  8. 3D simulation of the thermal and chemical plumes using open source software

    The interaction of thermal and chemical plumes in the region of the Irish Sea near the site has been simulated using a finite element model representative of the local hydrodynamic regime, concluding how the method of selected cooling, open cycle, is physically and environmentally feasible. Furthermore, tunnel lengths required for each scenario under discussion have been preliminarily defined, varying in a range from 1800 to 2300 meters for a unit (1 tunnel), 4400-6300 meters of two units (2 tunnels) and 8000 meters to three units (2 tunnels), depending on the chosen technology.

  9. Thermal-hydraulic system study of a high pressure, high temperature helium loop using RELAP5-3D code

    Highlights: ► A thermal-hydraulic system analysis for a high pressure, high temperature helium loop has been investigated. ► The loop belongs to the Helium Loop Karlsruhe (HELOKA) facility, which contains the European Helium Cooled Pebble Beds Test Blanket Module (HCPB TBM) as the test module. ► The loop including all components has been modeled using the system code REALP5-3D, and the main control strategy has been implemented as well. ► With this model, the loop dynamics in conditions relevant for blanket module operation have been demonstrated. - Abstract: The thermal-hydraulic system analysis for the Helium Loop Karlsruhe (HELOKA) facility, a high pressure, high temperature experimental helium loop having the European Helium Cooled Pebble Beds Test Blanket Module (HCPB TBM) as the test module, was investigated. Using the system code REALP5-3D, all components in the loop are modeled as well as the main control strategy. With this model, the loop dynamics in conditions relevant for blanket module operation are simulated and analyzed.

  10. Methodology for thermal budget reduction of SPER down to 450 °C for 3D sequential integration

    Luce, F. P.; Pasini, L.; Sklénard, B.; Mathieu, B.; Licitra, C.; Batude, P.; Mazen, F.

    2016-03-01

    3D sequential integration enables the full use of the third dimension thanks to its unique contact density far above the possibilities of 3D packaging solutions. However, as the transistors are sequentially stacked over each other, the thermal budget allowed for the fabrication of the top transistor is limited by the maximal temperature accepted by the already made bottom one. It was previously described that a thermal budget of T > 500 °C is enough to degrade the bottom transistors performance. So the technological challenge is to develop low temperature routines for the fabrication of the top devices. For that, different processes have to be adapted, mainly the dopant activation step, where the T > 1000 °C spike annealing must be replaced. In this contribution, we present the feasibility to dope by solid phase epitaxial regrowth (SPER) at 450 °C thin Si films (22 nm) containing high dopant concentration of 5 × 1020 at/cm3. For n- and p-type dopants, the 450 °C SPER rendered low sheet resistance values, as low as the ones obtained with the high temperature activation method.

  11. UNIQUIMER 3D, a software system for structural DNA nanotechnology design, analysis and evaluation

    Zhu, Jinhao; Wei, Bryan; Yuan, Yuan; Mi, Yongli

    2009-01-01

    A user-friendly software system, UNIQUIMER 3D, was developed to design DNA structures for nanotechnology applications. It consists of 3D visualization, internal energy minimization, sequence generation and construction of motif array simulations (2D tiles and 3D lattices) functionalities. The system can be used to check structural deformation and design errors under scaled-up conditions. UNIQUIMER 3D has been tested on the design of both existing motifs (holiday junction, 4 × 4 tile, double crossover, DNA tetrahedron, DNA cube, etc.) and nonexisting motifs (soccer ball). The results demonstrated UNIQUIMER 3D's capability in designing large complex structures. We also designed a de novo sequence generation algorithm. UNIQUIMER 3D was developed for the Windows environment and is provided free of charge to the nonprofit research institutions. PMID:19228709

  12. 3D thermal-hydraulic analysis on core of PWR nuclear power station

    Thermal hydraulic analysis of core is of great importance in reactor safety analysis. A computer code, thermal hydraulic analysis porous medium analysis (THAPMA), has been developed to simulate the flow and heat transfer characteristics of reactor components. It has been proved reliable by several numerical tests. In the THAPMA code, a new difference scheme and solution method have been studied in developing the computer software. For the difference scheme, a second order accurate, high resolution scheme, called WSUC scheme, has been proposed. This scheme is total variation bounded and unconditionally stable in convective numeral stability. Numerical tests show that the WSUC is better in accuracy and resolution than the 1-st order upwind, 2-nd order upwind, SOUCUP by Zhu and Rodi. In solution method, a modified PISO algorithm is used, which is not only simpler but also more accurate and more rapid in convergence than the original PISO algorithm. Moreover, the modified PISO algorithm can effectively solve steady and transient state problem. Besides, with the THAPMA code, the flow and heat transfer phenomena in reactor core have been numerically simulated in the light of the design condition of Qinshan PWR nuclear power station (the second-term project). The simulation results supply a theoretical basis for the core design

  13. CT colonography: evaluation of two 3D algorithms in a screening population

    Purpose: the purpose of this multicenter study was to compare a dissection display and an endoluminal display for CT colonography (CTC) by means of detection rates and evaluation time in a screening collective. Materials and methods: 4 blinded readers evaluated CTC datasets from 42 patients with 55 endoscopically confirmed polyps. The datasets were read in a randomized order using two different 3D visualization methods (endoluminal view vs. dissection display; EBW 2.0.1, Philips Medical Systems, Best/NL). Patients underwent cathartic cleansing as well as stool and fluid tagging. All readers except one were experienced in performing CTC. The per-lesion/per-patient sensitivity, per-patient specificity, and evaluation time were calculated. Results: the overall per-lesion sensitivity using the dissection display (and endoluminal view) was 60% (53%) for reader 1, 58% (60%) for reader 2, 67% (71%) for reader 3 and 55% (58%) for reader 4. The per-patient sensitivity using the dissection display (and endoluminal view) was 85% (85%) for reader 1, 80% (85%) for reader 2, 95% (90%) for reader 3 and 80% (80%) for reader 4. The per-patient specificity was 68% with dissection view (77% endoluminal view) for reader 1, 82% (82%) for reader 2, 59% (59%) for reader 3 and 82% (73%) for reader 4. The experienced readers were significantly faster using the perspective-filet view. (orig.)

  14. CCTV Coverage Index Based on Surveillance Resolution and Its Evaluation Using 3D Spatial Analysis

    Kyoungah Choi

    2015-09-01

    Full Text Available We propose a novel approach to evaluating how effectively a closed circuit television (CCTV system can monitor a targeted area. With 3D models of the target area and the camera parameters of the CCTV system, the approach produces surveillance coverage index, which is newly defined in this study as a quantitative measure for surveillance performance. This index indicates the proportion of the space being monitored with a sufficient resolution to the entire space of the target area. It is determined by computing surveillance resolution at every position and orientation, which indicates how closely a specific object can be monitored with a CCTV system. We present full mathematical derivation for the resolution, which depends on the location and orientation of the object as well as the geometric model of a camera. With the proposed approach, we quantitatively evaluated the surveillance coverage of a CCTV system in an underground parking area. Our evaluation process provided various quantitative-analysis results, compelling us to examine the design of the CCTV system prior to its installation and understand the surveillance capability of an existing CCTV system.

  15. Standardized Evaluation System for Left Ventricular Segmentation Algorithms in 3D Echocardiography.

    Bernard, Olivier; Bosch, Johan G; Heyde, Brecht; Alessandrini, Martino; Barbosa, Daniel; Camarasu-Pop, Sorina; Cervenansky, Frederic; Valette, Sebastien; Mirea, Oana; Bernier, Michel; Jodoin, Pierre-Marc; Domingos, Jaime Santo; Stebbing, Richard V; Keraudren, Kevin; Oktay, Ozan; Caballero, Jose; Shi, Wei; Rueckert, Daniel; Milletari, Fausto; Ahmadi, Seyed-Ahmad; Smistad, Erik; Lindseth, Frank; van Stralen, Maartje; Wang, Chen; Smedby, Orjan; Donal, Erwan; Monaghan, Mark; Papachristidis, Alex; Geleijnse, Marcel L; Galli, Elena; D'hooge, Jan

    2016-04-01

    Real-time 3D Echocardiography (RT3DE) has been proven to be an accurate tool for left ventricular (LV) volume assessment. However, identification of the LV endocardium remains a challenging task, mainly because of the low tissue/blood contrast of the images combined with typical artifacts. Several semi and fully automatic algorithms have been proposed for segmenting the endocardium in RT3DE data in order to extract relevant clinical indices, but a systematic and fair comparison between such methods has so far been impossible due to the lack of a publicly available common database. Here, we introduce a standardized evaluation framework to reliably evaluate and compare the performance of the algorithms developed to segment the LV border in RT3DE. A database consisting of 45 multivendor cardiac ultrasound recordings acquired at different centers with corresponding reference measurements from three experts are made available. The algorithms from nine research groups were quantitatively evaluated and compared using the proposed online platform. The results showed that the best methods produce promising results with respect to the experts' measurements for the extraction of clinical indices, and that they offer good segmentation precision in terms of mean distance error in the context of the experts' variability range. The platform remains open for new submissions. PMID:26625409

  16. Performance Evaluating of some Methods in 3D Depth Reconstruction from a Single Image

    Wen, Wei

    2009-01-01

    We studied the problem of 3D reconstruction from a single image. The 3D reconstruction is one of the basic problems in Computer Vision. The 3D reconstruction is usually achieved by using two or multiple images of a scene. However recent researches in Computer Vision field have enabled us to recover the 3D information even from only one single image. The methods used in such reconstructions are based on depth information, projection geometry, image content, human psychology and so on. Each met...

  17. Network level pavement evaluation with 1 mm 3D survey system

    Wang, Kelvin C.P.; Qiang Joshua Li; Guangwei Yang; You Zhan; Yanjun Qiu

    2015-01-01

    The latest iteration of PaveVision3D Ultra can obtain true 1 mm resolution 3D data at full-lane coverage in all 3 directions at highway speed up to 60 mph. This paper introduces the PaveVision3D Ultra technology for rapid network level pavement survey on approximately 1280 center miles of Oklahoma interstate highways. With sophisticated automated distress analyzer (ADA) software interface, the collected 1 mm 3D data provide Oklahoma Department of Transportation (ODOT) with comprehensive solut...

  18. Evaluating the accuracy of orthophotos and 3D models from UAV photogrammetry

    Julge, Kalev; Ellmann, Artu

    2015-04-01

    Rapid development of unmanned aerial vehicles (UAV) in recent years has made their use for various applications more feasible. This contribution evaluates the accuracy and quality of different UAV remote sensing products (i.e. orthorectified image, point cloud and 3D model). Two different autonomous fixed wing UAV systems were used to collect the aerial photographs. One is a mass-produced commercial UAV system, the other is a similar state-of-the-art UAV system. Three different study areas with varying sizes and characteristics (including urban areas, forests, fields, etc.) were surveyed. The UAV point clouds, 3D models and orthophotos were generated with three different commercial and free-ware software. The performance of each of these was evaluated. The effect of flying height on the accuracy of the results was explored, as well as the optimum number and placement of ground control points. Also the achieved results, when the only georeferencing data originates from the UAV system's on-board GNSS and inertial measurement unit, are investigated. Problems regarding the alignment of certain types of aerial photos (e.g. captured over forested areas) are discussed. The quality and accuracy of UAV photogrammetry products are evaluated by comparing them with control measurements made with GNSS-measurements on the ground, as well as high-resolution airborne laser scanning data and other available orthophotos (e.g. those acquired for large scale national mapping). Vertical comparisons are made on surfaces that have remained unchanged in all campaigns, e.g. paved roads. Planar comparisons are performed by control surveys of objects that are clearly identifiable on orthophotos. The statistics of these differences are used to evaluate the accuracy of UAV remote sensing. Some recommendations are given on how to conduct UAV mapping campaigns cost-effectively and with minimal time-consumption while still ensuring the quality and accuracy of the UAV data products. Also the

  19. Accuracy evaluation of initialization-free registration for intraoperative 3D-navigation

    Purpose An initialization-free approach for perioperative registration in functional endoscopic sinus surgery (FESS) is sought. The quality of surgical navigation relies on registration accuracy of preoperative images to the patient. Although landmark-based registration is fast, it is prone to human operator errors. This study evaluates the accuracy of two well-known methods for segmentation of the occipital bone from CT-images for use in surgical 3D-navigation. Method The occipital bone was segmented for registration without pre-defined correspondences, with the iterative closest point algorithm (ICP). The thresholding plus marching cubes segmentation (TMCS), and the deformable model segmentation (DMS) were compared quantitatively by overlaying the areas of the segmentations in cross-sectional slices, and visually by displaying the pointwise distances between the segmentations in a three-dimensional distance map relative to an expert manual segmentation, taken as a ''ground truth''. Results Excellent correspondence between the two methods was achieved; the results showed, however, that the TMCS is closer to the ''ground truth''. This is due to the sub-voxel accuracy of the marching cubes algorithm by definition, and the sensitivity of the DMS method to the choice of parameters. The DMS approach, as a gradient-based method, is insensitive to the thresholding initialization. For noisy images and soft tissue delineation a gradient-based method, like the deformable model, performs better. Both methods correspond within minute differences less than 4%. Conclusion These results will allow further minimization of human interaction in the planning phase for intraoperative 3D-navigation, by allowing to automatically create surface patches for registration purposes, ultimately allowing to build an initialization-free, fully automatic registration procedure for navigated Ear-, Nose-, Throat- (ENT) surgery. (orig.)

  20. Accuracy evaluation of initialization-free registration for intraoperative 3D-navigation

    Diakov, Georgi; Freysinger, Wolfgang [University Clinic of Oto-, Rhino-, Laryngology, Innsbruck Medical University, 4D Visualization Laboratory, Innsbruck (Austria)

    2007-08-15

    Purpose An initialization-free approach for perioperative registration in functional endoscopic sinus surgery (FESS) is sought. The quality of surgical navigation relies on registration accuracy of preoperative images to the patient. Although landmark-based registration is fast, it is prone to human operator errors. This study evaluates the accuracy of two well-known methods for segmentation of the occipital bone from CT-images for use in surgical 3D-navigation. Method The occipital bone was segmented for registration without pre-defined correspondences, with the iterative closest point algorithm (ICP). The thresholding plus marching cubes segmentation (TMCS), and the deformable model segmentation (DMS) were compared quantitatively by overlaying the areas of the segmentations in cross-sectional slices, and visually by displaying the pointwise distances between the segmentations in a three-dimensional distance map relative to an expert manual segmentation, taken as a ''ground truth''. Results Excellent correspondence between the two methods was achieved; the results showed, however, that the TMCS is closer to the ''ground truth''. This is due to the sub-voxel accuracy of the marching cubes algorithm by definition, and the sensitivity of the DMS method to the choice of parameters. The DMS approach, as a gradient-based method, is insensitive to the thresholding initialization. For noisy images and soft tissue delineation a gradient-based method, like the deformable model, performs better. Both methods correspond within minute differences less than 4%. Conclusion These results will allow further minimization of human interaction in the planning phase for intraoperative 3D-navigation, by allowing to automatically create surface patches for registration purposes, ultimately allowing to build an initialization-free, fully automatic registration procedure for navigated Ear-, Nose-, Throat- (ENT) surgery. (orig.)

  1. 3D RECONSTRUCTION FROM MULTI-VIEW MEDICAL X-RAY IMAGES – REVIEW AND EVALUATION OF EXISTING METHODS

    S. Hosseinian

    2015-12-01

    Full Text Available The 3D concept is extremely important in clinical studies of human body. Accurate 3D models of bony structures are currently required in clinical routine for diagnosis, patient follow-up, surgical planning, computer assisted surgery and biomechanical applications. However, 3D conventional medical imaging techniques such as computed tomography (CT scan and magnetic resonance imaging (MRI have serious limitations such as using in non-weight-bearing positions, costs and high radiation dose(for CT. Therefore, 3D reconstruction methods from biplanar X-ray images have been taken into consideration as reliable alternative methods in order to achieve accurate 3D models with low dose radiation in weight-bearing positions. Different methods have been offered for 3D reconstruction from X-ray images using photogrammetry which should be assessed. In this paper, after demonstrating the principles of 3D reconstruction from X-ray images, different existing methods of 3D reconstruction of bony structures from radiographs are classified and evaluated with various metrics and their advantages and disadvantages are mentioned. Finally, a comparison has been done on the presented methods with respect to several metrics such as accuracy, reconstruction time and their applications. With regards to the research, each method has several advantages and disadvantages which should be considered for a specific application.

  2. QUARK, 2-Group 3-D Neutronic Kinetics Coupled to Core Thermal-hydraulics

    1 - Description of program or function: QUARK is a combined computer program comprising a revised version of the QUANDRY three-dimensional two-group neutron kinetics code and an upgraded version of the COBRA transient core analysis code (COBRA-EN). Starting from either a critical steady-state (k-effective or critical dilute Boron problem) or a subcritical steady-state (fixed source problem) in a PWR plant, the code allows to simulate the neutronic and thermal-hydraulic core transient response to reactivity accidents initiated both inside the vessel (such as a control rod ejection) and outside the vessel (such as the sudden change of the Boron concentration in the coolant). 2 - Methods: The thermal-hydraulic model is based on three partial differential equations that describe the conservation of mass, energy and momentum for the water liquid/vapor mixture and the interaction of the two-phase coolant with the system structures. Optionally, a fourth equation can be added which tracks the vapor mass separately and which, along with the correlations for vapor generation and slip ratio, replaces the subcooled quality and quality/void fraction correlations, needed by the homogeneous model. In each coolant channel, the one-dimensional (z) fluid dynamics equations in the vertical direction as well as the one-dimensional (r) equation in the horizontal direction that models the heat transfer in solid structures are approximated by finite differences. The resulting equations for hydrodynamic phenomena form a system of coupled nonlinear equations that are solved by the Original upflow scheme (when no reverse flow is predicted) or by a Newton-Raphson iteration procedure. The heat-transfer equations in the solid structures are treated implicitly. Moreover, a full boiling curve is provided, comprising the basic heat-transfer regimes, each represented by a set of optional correlations for the heat-transfer coefficient between a solid surface and the coolant bulk. The neutronic

  3. Fabrication of 3D Microfluidic Devices by Thermal Bonding of Thin Poly(methyl methacrylate) Films

    Perez, Paul

    2012-07-01

    The use of thin-film techniques for the fabrication of microfluidic devices has gained attention over the last decade, particularly for three-dimensional channel structures. The reasons for this include effective use of chip volume, mechanical flexibility, dead volume reduction, enhanced design capabilities, integration of passive elements, and scalability. Several fabrication techniques have been adapted for use on thin films: laser ablation and hot embossing are popular for channel fabrication, and lamination is widely used for channel enclosure. However, none of the previous studies have been able to achieve a strong bond that is reliable under moderate positive pressures. The present work aims to develop a thin-film process that provides design versatility, speed, channel profile homogeneity, and the reliability that others fail to achieve. The three building blocks of the proposed baseline were fifty-micron poly(methyl methacrylate) thin films as substrates, channel patterning by laser ablation, and device assembly by thermal-fusion bonding. Channel fabrication was characterized and tuned to produce the desired dimensions and surface roughness. Thermal bonding was performed using an adapted mechanical testing device and optimized to produce the maximum bonding strength without significant channel deformation. Bonding multilayered devices, incorporating conduction lines, and integrating various types of membranes as passive elements demonstrated the versatility of the process. Finally, this baseline was used to fabricate a droplet generator and a DNA detection chip based on micro-bead agglomeration. It was found that a combination of low laser power and scanning speed produced channel surfaces with better uniformity than those obtained with higher values. In addition, the implemented bonding technique provided the process with the most reliable bond strength reported, so far, for thin-film microfluidics. Overall, the present work proved to be versatile

  4. Multi-scale uncertainty and sensitivity analysis of the TALL-3D experiment using thermal-hydraulic coupled codes

    The simulation of complex thermal-hydraulic phenomena is a challenging task. On one hand Computational Fluid Dynamics (CFD) codes allow a fine resolution of 3D phenomena but have a computational cost which is still prohibitive for some applications. On the other hand, System Analysis codes are fast running but cannot account for 3D phenomena. The coupling of these two approaches provides a tool which combines their advantages. In the context of the European THINS Project (7th Framework Program) the Gesellschaft für Anlagen- und Reaktorsicherheit mbH (GRS) developed a coupling between ANSYS CFX and ATHLET. The validation of this coupled code is to be performed with the help of experimental data provided by KTH (Sweden), which has built the TALL-3D facility for this purpose. This facility investigates the transition from forced to natural circulation of the Lead-Bismuth Eutectic (LBE) in a pool connected to a 3-leg primary circuit with two heaters and a heat exchanger. TUM is responsible for the Uncertainty and Sensitivity Analysis (USA) of the coupled ATHLET-CFX simulations in the THINS Project. The influence of modeling uncertainty on the simulation results needs to be assessed because it can significantly impair their accuracy. USA is a powerful tool to assess the model output variability resulting from modeling uncertainty (Uncertainty Analysis) and to identify and rank the influential model input parameters (Sensitivity Analysis). TUM has developed a computational framework to propagate modeling uncertainty through coupled Systems Analysis – Computational Fluid Dynamics (CFD) codes. This framework is being applied to the simulation of the experiments performed on the TALL-3D facility. The uncertainty methodology used is based on the statistical sampling of the uncertain inputs and models used by the two codes, its propagation through coupled calculations, and the final processing of the output sample of variables of interest with non-parametric statistical

  5. Ultrasound and 3D Skin Imaging: Methods to Evaluate Efficacy of Striae Distensae Treatment

    Mariella Bleve

    2012-01-01

    Full Text Available Background. Over time, the striae rubra develop into striae alba that appear white, flat, and depressed. It is very important to determine the optimum striae management. In order to evaluate the effectiveness of these therapies, objective measurement tools are necessary. Objective. The aim of this study is to evaluate if ultrasonography and PRIMOS can be used to obtain an objective assessment of stretch marks type and stage; furthermore, we aim to apply these techniques to evaluate the efficacy of a topical treatment. Methods. 20 volunteers were enrolled with a two-month study. A marketed cosmetic product was used as the active over one body area. The controlateral area with stretch marks was treated with a “placebo” formulation without active, as a control. The instrumental evaluation was carried out at the beginning of the trial (baseline values or 0, after 1 month (1, and at the end of the study (2. Results. PRIMOS was able to measure and document striae distensae maturation; furthermore, ultrasound imaging permitted to visualize and diagnose the striae. Statistical analysis of skin roughness demonstrated a statistically significant reduction of Rp value only in a treated group. In fact, the Rp value represented a maximum peak height in the area selected. These results demonstrated that after two months of treatment only the striae rubra can be treated successfully. Conclusions. This work demonstrated that the 22MHz ultrasound can diagnose stretch marks; PRIMOS device can detect and measure striae distensae type and maturation. Furthermore, the high-frequency ultrasound and the 3D image device, described in this work, can be successfully employed in order to evaluate the efficacy of a topical treatment.

  6. A 3D Osteoblast In Vitro Model for the Evaluation of Biomedical Materials

    Luciana Restle

    2015-01-01

    Full Text Available Biomedical materials for bone therapy are usually assessed for their biocompatibility and safety employing animal models or in vitro monolayer cell culture assays. However, alternative in vitro models may offer controlled conditions closer to physiological responses and reduce animal testing. In this work, we developed a 3D spheroidal cell culture with potential to evaluate simultaneously material-cell and cell-cell interactions. Different cell densities of murine MC3T3-E1 preosteoblasts or human primary osteoblasts (HOb were used to determine the ideal procedure of spheroidal cultures and their adequacy to material testing. Cells were seeded on 96-well plates coated with agar and incubated in agitation from 1 to 7 days. Aggregate morphology was qualitatively evaluated considering the shape, size, repeatability, handling, and stability of spheroids. Higher cell densities induced more stable spheroids, and handling was considered appropriate starting from 2 × 104 cells. Confocal microscopy and Scanning Electron Microscopy indicate that most cells within the aggregate core are viable. Exposure to positive controls has shown a dose dependent cell death as measured by XTT assay. Aggregates were stable and presented good viability when employed on standardized testing of metallic and polymer-based biomaterials. Therefore, osteoblast spheroids may provide a promising tool for material screening and biocompatibility testing.

  7. 3D-CT evaluation of secondary alveolar bone grafts in alveolar clefts

    Naitoh, Hiroshi; Nishimura, Yoshihiko [Kyoto Univ. (Japan). Graduate School of Medicine; Yamawaki, Yoshiroh [Kyoto Katsura Hospital (Japan); Morimoto, Naoki [Kobe City General Hospital (Japan)

    2002-07-01

    From 1994 to 2000, we treated 116 patients with cleft alveolus by secondary alveolar bone grafts, and 48 of them were evaluated morphologically with 3D-CT. The frequency of successful bony bridging was significantly higher in the group whose grafts were completely enveloped (including the anterior alveolar ridge) with a mucoperiosteal flap. The frequency was also significantly higher in the group who underwent bone grafts at the age of 13 or less, and canine eruptions did not influence the ratio. Some cases showed such an improved growth pattern of grafted bone that the shape of the affected maxilla resembled that of the normal side, after long-term follow-up observations. The growth increment was remarkable in anterior maxillary height. Orthodontic management guides the canine or incisor into the reconstructed area of the previous cleft. We surmise that the new occlusal position puts pressure on the grafted bone and promotes further osteogenesis. These findings show that it is important to produce sufficient bony bridge to guide the canine or incisor, not the volume of grafted bone, in secondary alveolar bone grafts. Long-term follow-up observation, after more than 2-3 years, is also necessary to evaluate secondary alveolar bone grafts. (author)

  8. Development of Radioactive Inventory Evaluation System using 3D Shape and Multiple Radiation Measurement

    The increase of the operating NPPs and the superannuation of the equipment in NPPs cause a large amount of the metal radioactive waste. Presently the metal radioactive wastes are stored in the temporary storage facility in NPPs because of the delay of the construction of the final disposal facility. The radioactive level of general metal radioactive wastes is low, and the radioactive level can be lowered by the simple decontamination process. If the radioactive wastes are disposed as the industry waste, the disposal cost is diminished largely. For the disposal of the radioactive wastes as the industrial wastes, the radioactive level of the target wastes are evaluated. It is difficult to know the position of the source term for most of the metal radioactive and the source term is distributed non-homogeneously. And the self-shielding effect of the metal material makes the evaluation more difficult. In this study, the radioactive inventory evaluation system for the metal radioactive waste is developed. For the correction of the uncertainty of the position and the non-homogeneity of the source term, the 3D shape and multiple radiation measurement are used. The existing gamma-ray measurement system for the metal radioactive waste cannot reflect the position and the distribution of the source term and the effect of self-shielding. This evaluation system suggested in this system can calculate the reasonable value regarding to the position and the distribution of the source term and the effect of self-shielding. By the calculation of the partial inventory of the target metal waste, the advantage in the application of the clearance criteria can be obtained

  9. Evaluation of pharyngeal volume and compliance of OSAHS patients using 3D CT and volume measurement

    The intrinsic properties such as baseline caliber and compliance of the upper airway are thought to be important in the pathogenesis of obstructive sleep apnea hypopnea syndrome (OSAHS).The author attempted using imaging methods to evaluate both baseline caliber and compliance in normal individuals and OSAHS patients, and to localize the obstructive sites in OSAHS patients. Critical closing pressure (Pcrit) and minimally effective therapeutical pressure (Peff) were measured and computed tomography (CT) scan of pharynx was performed during wakefulness and drug-induced sleep with Pcrit, 0 cm H2O and Peff being given through a nose mask system. 7 normal individuals (age, 32.2±6.5 y's and body mass index, 23.6±5.4 kg/m2) and 13 OSAHS patients (age, 33.3±6.4 y's and body mass index, 25.9±6.0 kg/m2) were studied. 3D images of pharyngeal airway were reconstructed, and volume of each subdivision of pharynx was measured. Volume, average area and compliance of each subdivision were compared between the two groups. On an air-mode view of 3D image, the outline of pharynx was shown as transparent tubal structure, on which the narrowing collapse of airway at any level or any direction can be easily identified. Anatomy of pharynx could be easily understood on the virtual endoscopic mode. During wakefulness, the average area of the upper (1.20±0.26 cm2 vs. 1.57±0.17 cm2, P2 vs. 2.58±0.27 cm2, P2 vs. 1.45±0.18 cm2, P2 vs. 2.44±0.26 cm2). The compliance of the middle part (0.28±0.15/cmH2O vs. 0.13±0.07/cmH2O, P<0.05) of pharynx was significantly higher in OSAHS patients than in normal individuals. The data suggested that OSAHS patients have a narrower and more collapsible pharynx compared to the normal subjects. The method of the present study is valid to evaluate both morphology and function of the upper airway. (author)

  10. Comparative evaluation of scatter correction in 3D PET using different scatter-level approximations

    In 3D positron emission tomography (PET), scatter of the gamma photons is one of the most significant physical factors which degrades not only image quality but also quantification. The currently most used scatter estimation method is the analytic single scatter simulation (SSS) which usually accommodates for multiple scattering by scaling the single scatter estimation. However, it has not been clear yet how accurate this approximation is for cases where multiple scatter is significant, raising the question: 'How important is correction for multiple scattered photons, and how accurately do we need to simulate all scattered events by appropriate scaling?' This study answers these questions and evaluates the accuracy of SSS implementation in the open-source library software for tomographic image reconstruction (STIR). Different scatter orders approximations are evaluated including different levels of scattering and different scaling approaches using Monte Carlo (id est (i.e.) Sim system for emission tomography (SET)) data. SimSET simulations of a large anthropomorphic phantom were reconstructed with iterative reconstruction algorithms. Images reconstructed with 3D filtered back-projection reprojection algorithm have been compared quantitatively in order to clarify the errors due to different scatter order approximations. Quantification in regions has improved by scatter correction. For example, in the heart the ideal value was 3, whereas before scatter correction the standard uptake value (SUV) was 4.0, after single scatter correction was 3.3 and after single and double scatter correction was 3.0. After correction by scaling single scatter with tail-fit, the SUV was 3.1, whereas with total-fit it was 3.0. Similarly, for the SSS correction methodology implemented in STIR using tail-fit the heart SUV was 3.1 whereas using total-fit it was 3.0. The results demonstrate that correction for double scatter improves image contrast and therefore it is required for the

  11. An Evaluation of 3D Woven Orthogonal Composites' Potential in the Automotive Supply Chain

    Taylor, Dalia

    The automotive supply chain and its management can be a very complex process and comprises a long dynamic and complex network that consists of four primary segments: original equipment manufacturers (OEMs), first tier suppliers, sub tiers suppliers, and infrastructure suppliers. During the analysis of the current automotive industry it was identified that textile industry importance is considerable increasing as a part of the global automotive supply chain, because textile products are used for interior, exterior and even suspension parts and components. Automotive industry has an increasing demand for higher quality exterior panels with better functional properties and reduced weight. One of the main potentials for this demand is based on the three-dimensional woven composites technology innovations which can replace an existing technology. The new role of the textile industry could make important changes in the automotive supply chain industry, such as: changes in the size of the supply chain, the time to the market and the position of textile industry in the automotive supply chain structure. 3D composite materials from high performance fibers, such as glass and carbon, have been used for automotive applications in a limited way due to the low production rate and the lack of research and development. This research will contribute to the understanding of textile composites in transportation and the textile parameters that affect the performance characteristics of these materials. The research examines the performance characteristics of lighter and stronger 3D woven fabric composites made from fiberglass with the aim to improve fuel efficiency by reducing the total vehicle weight while maintaining safety standards. The performance characteristics of the 3D woven fabric composite can be designed by changing different construction parameters, such as picks density, pick roving linear density, arrangements of warp and z-yarns, and the number of warp and picks layers

  12. Evaluation of the correctness of a 3D recording device for mandibular functional movement in laboratory

    Zhao, Tian; Sui, Huaxin; Yang, Huifang; Wang, Yong; Sun, Yuchun

    2015-07-01

    Objectives: To quantitatively evaluate the correctness of a computer binocular vision mandibular 3D trajectory recording device. Methods: A specialized target shooting paper was neatly pasted on a high-precision three-axis electronic translation stage. A linear one-way movement was set at a speed of 1 mm/s along the X, Y, and Z directions for a distance of 10 mm each. The coordinates of 3 pre-set target points were recorded at the start and end by a computer binocular vision system with a frequency of 10 FPS and stored in TXT format. The TXT files were imported to Imageware 13.0, and the straight-line lengths between the start and end were measured. The mean difference between each length and 10 mm were calculated to evaluate the correctness of the distance measurement. The linear movement and recording procedure was repeated 3 times, but the speed was changed to 5 mm/s to simulate the human mandibular movement speed. The trajectories of the 3 target points were fitted and the vertical dimensions from each track point to the fitted lines were measured. The mean difference was calculated between the vertical dimensions and 0 mm to evaluate the correctness of recording trajectories using this device. Results: The correctness of distance measurements of the points 1, 2, and 3 were 0.06 mm, 0.16 mm, and 0.08 mm, respectively. The correctness of the trajectories of the points 1, 2, and 3 were 0.11 mm, 0.11 mm, and 0.10 mm, respectively. Conclusion: Using this computer binocular vision device, the correctness of the recorded linear trajectories in the range of 10 mm was better than 0.20 mm.

  13. Accuracy of 3D white light scanning of abutment teeth impressions: evaluation of trueness and precision

    Jeon, Jin-Hun; Kim, Hae-Young; Kim, Ji-Hwan

    2014-01-01

    PURPOSE This study aimed to evaluate the accuracy of digitizing dental impressions of abutment teeth using a white light scanner and to compare the findings among teeth types. MATERIALS AND METHODS To assess precision, impressions of the canine, premolar, and molar prepared to receive all-ceramic crowns were repeatedly scanned to obtain five sets of 3-D data (STL files). Point clouds were compared and error sizes were measured (n=10 per type). Next, to evaluate trueness, impressions of teeth were rotated by 10°-20° and scanned. The obtained data were compared with the first set of data for precision assessment, and the error sizes were measured (n=5 per type). The Kruskal-Wallis test was performed to evaluate precision and trueness among three teeth types, and post-hoc comparisons were performed using the Mann-Whitney U test with Bonferroni correction (α=.05). RESULTS Precision discrepancies for the canine, premolar, and molar were 3.7 µm, 3.2 µm, and 7.3 µm, respectively, indicating the poorest precision for the molar (Pteeth types were 6.2 µm, 11.2 µm, and 21.8 µm, respectively, indicating the poorest trueness for the molar (P=.007). CONCLUSION In respect to accuracy the molar showed the largest discrepancies compared with the canine and premolar. Digitizing of dental impressions of abutment teeth using a white light scanner was assessed to be a highly accurate method and provided discrepancy values in a clinically acceptable range. Further study is needed to improve digitizing performance of white light scanning in axial wall. PMID:25551007

  14. Clinical evaluation of 3D-CT cholangiography for preoperative examination in laparoscopic cholecystectomy

    Kinami, Shinichi; Yao, Tadashi; Kurachi, Madoka; Ishizaki, Yoshio [Inami Public General Hospital, Toyama (Japan)

    1999-02-01

    Three-dimensional-computed tomography (3D-CT) cholangiography is a 3D shaded surface display image of the biliary tract obtained by using helical CT after intravenous cholangiography or cholangiography per percutaneous transhepatic cholangio-drainage tube. We investigated whether 3D-CT cholangiography could provide a useful image, for preoperative examination in laparoscopic cholecystectomy. Sixty-five patients with biliary diseases were examined by 3D-CT cholangiography. Helical scanning was performed on a Proceed Accell (GE Medical Systems, Waukesha, WI, USA). Three-dimensional images were created using an independent workstation. A clear image of the common bile duct was obtained for all patients (100%) by 3D-CT cholangiography. The gallbladder was well visualized in 54 (93%) and the cystic duct was shown to be opacified in 55 (95%) of the 58 patients with a gallbladder. Thirty-one patients were diagnosed as having gallstones by 3D-CT cholangiography (sensitivity, 72.1%; specificity, 100%; accuracy, 79.3%), while 43 were diagnosed as having cholecystolithiasis by ultrasonography. The advantages of 3D-CT cholangiography were a low level of invasiveness, easily obtained images compared to those obtained with endoscopic retrograde cholangiography (ERC), good opacification, and provision of a three-dimensional understanding of the biliary system, especially of the cystic duct. When combined with ultrasonography and routine liver function tests, 3D-CT cholangiography was considered very useful for obtaining information before laparoscopic cholecystectomy. It allowed the omission of ERC in many patients who were considered to have no common bile duct stone, by employment of 3D-CT cholangiography. (author)

  15. Thermal-Hydraulic Calculation for Simplified Fuel Assembly of Super Fast Reactor Using Two-Fluid Model Analysis Code ACE-3D

    To evaluate thermal hydraulic characteristics of a fuel assembly of supercritical water-cooled fast reactor (Super Fast Reactor), a simplified fuel assembly was analyzed with a three-dimensional two-fluid model analysis code ACE-3D which has been enhanced by Japan Atomic Energy Agency. In the ACE-3D code, the two-phase flow turbulent model based on the k-ε model were adopted. The analytical geometry simulates a 19-rod fuel assembly, which is a simplified geometry of the 271-rod fuel assembly and includes all three kinds of different subchannel types; (1): adjoining to the channel box, (2): next to type (1), and (3): located inside types (1) and (2). In this calculation, one-twelfth model is adopted as the computational domain taking advantage of symmetry. As the boundary conditions, mass velocity, inlet enthalpy and power per rod are to be the same as the steady state condition of the Super Fast Reactor. Cross-sectional local power distribution in the fuel assembly is set to be flat. Rod surface temperatures take peak values near the top of the rods. Maximum clad surface temperature (MCST) is observed at the position facing to the narrowest gap on the center rod near the outlet and the value is 902 K (629 deg. C). It was confirmed that the predicted MCST satisfies a thermal design criteria to ensure fuel and cladding integrity: the MCST should be less than 650 deg. C. (author)

  16. Survey on RGB, 3D, Thermal, and Multimodal Approaches for Facial Expression Recognition: History, Trends, and Affect-Related Applications.

    Corneanu, Ciprian Adrian; Simon, Marc Oliu; Cohn, Jeffrey F; Guerrero, Sergio Escalera

    2016-08-01

    Facial expressions are an important way through which humans interact socially. Building a system capable of automatically recognizing facial expressions from images and video has been an intense field of study in recent years. Interpreting such expressions remains challenging and much research is needed about the way they relate to human affect. This paper presents a general overview of automatic RGB, 3D, thermal and multimodal facial expression analysis. We define a new taxonomy for the field, encompassing all steps from face detection to facial expression recognition, and describe and classify the state of the art methods accordingly. We also present the important datasets and the bench-marking of most influential methods. We conclude with a general discussion about trends, important questions and future lines of research. PMID:26761193

  17. 3D FE Analysis of Thermal Behavior of Billet in Rod and Wire Hot Continuous Rolling Process

    YUAN Si-yu; ZHANG Li-wen; LIAO Shu-lun; QI Min; ZHEN Yu; GUO Shu-qi

    2007-01-01

    An FE model was developed to study thermal behavior during the rod and wire hot continuous rolling process. The FE code MSC.Marc was used in the simulation using implicit static arithmetic. The whole rolling process of 30 passes was separated and simulated with several continuous 3D elastic-plastic FE models. A rigid pushing body and a data transfer technique were introduced into this model. The on-line experiments were conducted on 304 stainless steel and GCr15 steel hot continuous rolling process to prove the results of simulation by implicit static FEM. The results show that the temperature results of finite element simulations are in good agreement with experiments, which indicate that the FE model developed in this study is effective and efficient.

  18. RELAP5-3D thermal hydraulic analysis of the target cooling system in the SPES experimental facility

    The SPES (Selective Production of Exotic Species) experimental facility, under construction at the Italian National Institute of Nuclear Physics (INFN) Laboratories of Legnaro, Italy, is a second generation Isotope Separation On Line (ISOL) plant for advanced nuclear physic studies. The UCx target-ion source system works at temperature of about 2273 K, producing a high level of radiation (105 Sv/h), for this reason a careful risk analysis for the target chamber is among the major safety issues. In this paper, the obtained results of thermofluid-dynamics simulations of accidental transients in the SPES target cooling system are reported. The analysis, performed by using the RELAP5-3D 2.4.2 qualified thermal-hydraulic system code, proves good safety performance of this system during different accidental conditions

  19. Evaluating Dense 3d Reconstruction Software Packages for Oblique Monitoring of Crop Canopy Surface

    Brocks, S.; Bareth, G.

    2016-06-01

    Crop Surface Models (CSMs) are 2.5D raster surfaces representing absolute plant canopy height. Using multiple CMSs generated from data acquired at multiple time steps, a crop surface monitoring is enabled. This makes it possible to monitor crop growth over time and can be used for monitoring in-field crop growth variability which is useful in the context of high-throughput phenotyping. This study aims to evaluate several software packages for dense 3D reconstruction from multiple overlapping RGB images on field and plot-scale. A summer barley field experiment located at the Campus Klein-Altendorf of University of Bonn was observed by acquiring stereo images from an oblique angle using consumer-grade smart cameras. Two such cameras were mounted at an elevation of 10 m and acquired images for a period of two months during the growing period of 2014. The field experiment consisted of nine barley cultivars that were cultivated in multiple repetitions and nitrogen treatments. Manual plant height measurements were carried out at four dates during the observation period. The software packages Agisoft PhotoScan, VisualSfM with CMVS/PMVS2 and SURE are investigated. The point clouds are georeferenced through a set of ground control points. Where adequate results are reached, a statistical analysis is performed.

  20. Evaluation of Bogie Frame Safety of Shanghai Metro Line 1 by 3D FEM Analysis

    Xiongyao, Xie; Guolong, Jin; Rulu, Wang

    2010-05-01

    The vehicle bogies of Shanghai metro line 1 began to crack just in the third year after the trains operated. More than 50 cracks occurred in the succeeding six year during the train operation. This paper evaluated the safety of the motorized bogies. First, the loading conditions imposed on the vehicle structure were calculated based on the measured data in service of the train, and compared with the original design load. Then, this paper calculated simulated the stress of the vehicle bogie by 3D FEM, and presented the distribution of every stress concentration point in Goodman fatigue diagram. The computational locations of the strength less than the safety are agreed with where cracks have happened. Finally, this paper calculated the fatigue life of the motor bracket of the bogie through S-N curve based on revised Miner theory. In conclusion, this paper think that the bogie cracks of Shanghai metro line 1 are contributed by the overburden fatigue load, and ignoring the lateral vibration load in the design of the vehicle bogie is the important cause that bogie cracks occurred far earlier than in the designed time.

  1. Mammogram synthesis using a 3D simulation. II. Evaluation of synthetic mammogram texture

    We have evaluated a method for synthesizing mammograms by comparing the texture of clinical and synthetic mammograms. The synthesis algorithm is based upon simulations of breast tissue and the mammographic imaging process. Mammogram texture was synthesized by projections of simulated adipose tissue compartments. It was hypothesized that the synthetic and clinical texture have similar properties, assuming that the mammogram texture reflects the 3D tissue distribution. The size of the projected compartments was computed by mathematical morphology. The texture energy and fractal dimension were also computed and analyzed in terms of the distribution of texture features within four different tissue regions in clinical and synthetic mammograms. Comparison of the cumulative distributions of the mean features computed from 95 mammograms showed that the synthetic images simulate the mean features of the texture of clinical mammograms. Correlation of clinical and synthetic texture feature histograms, averaged over all images, showed that the synthetic images can simulate the range of features seen over a large group of mammograms. The best agreement with clinical texture was achieved for simulated compartments with radii of 4-13.3 mm in predominantly adipose tissue regions, and radii of 2.7-5.33 and 1.3-2.7 mm in retroareolar and dense fibroglandular tissue regions, respectively

  2. A global 3-D CTM evaluation of black carbon in the Tibetan Plateau

    C. He

    2014-03-01

    Full Text Available We evaluate the black carbon (BC simulations for 2006 over the Tibetan Plateau by a global 3-D chemical transport model using surface observations of BC in surface air and in snow and BC absorption aerosol optical depth (AAOD. Using updated Asian anthropogenic BC emissions (Lu et al., 2011; Zhang et al., 2009 and global biomass burning emissions (Randerson et al., 2012; van der Werf et al., 2010, model results of both surface BC and BC in snow are statistically in good agreement with observations (biases < 15%. Model results capture the seasonal variation of surface BC concentration, but the observed wintertime high values at rural sites in the Indo-Gangetic Plain are absent in the model. Model results are in general agreement with observations (within a factor of two at remote sites. Model simulated BC concentrations in snow are spatiotemporally consistent with observations at most sites. We find that modeled BC AAOD are significantly lower than observations to the northwest of the Plateau and along the southern slopes of the Himalayas during winter and spring, reflecting model deficiencies in emissions, topography and BC mixing state. We find that anthropogenic emissions strongly affect surface BC concentration and AAOD, while the BC aging mainly affects BC in snow over the Plateau.

  3. Synthesis, characterization, antifungal evaluation and 3D-QSAR study of phenylhydrazine substituted tetronic acid derivatives.

    Hu, Ying; Wang, Junjun; Lu, Aimin; Yang, Chunlong

    2014-08-15

    A series of 3-(1-(2-(substituted phenyl)hydrazinyl)alkylidene)furan-2,4(3H,5H)-diones were designed and prepared using two synthetic routes. Their structures were confirmed by FT-IR, (1)H NMR, (13)C NMR, MS, elemental analysis and single-crystal X-ray diffraction. Their bioactivity was evaluated against Botrytis cinerea in vitro. Most target compounds exhibited remarkable antifungal activity. Two compounds 7f and 7h were highly effective and their EC50 values were 0.241 μg/mL and 0.167 μg/mL, respectively, close to that of the control drug procymidone. 3D-QSAR studies of CoMFA and CoMSIA were carried out. Models with good predictive ability were generated with the cross validated q(2) values for CoMFA and CoMSIA being 0.565 and 0.823. Conventional r(2) values were 0.983 and 0.945, respectively. The results provided a practical tool for guiding the design and synthesis of novel and more potent tetronic acid derivatives containing substituted phenylhydrazine moiety. PMID:25042337

  4. 3D simulation of the thermal and chemical plumes using open source software; Simulacion 3D de las plumas termica y quimica mediante software de codigo libre

    Saenz Temino, J. L.; Lerones Martin, J.; Gonzalez Delgado, J.

    2013-07-01

    The interaction of thermal and chemical plumes in the region of the Irish Sea near the site has been simulated using a finite element model representative of the local hydrodynamic regime, concluding how the method of selected cooling, open cycle, is physically and environmentally feasible. Furthermore, tunnel lengths required for each scenario under discussion have been preliminarily defined, varying in a range from 1800 to 2300 meters for a unit (1 tunnel), 4400-6300 meters of two units (2 tunnels) and 8000 meters to three units (2 tunnels), depending on the chosen technology.

  5. Evaluation of Fully 3-D Emission Mammotomography With a Compact Cadmium Zinc Telluride Detector

    Brzymialkiewicz, Caryl N.; Martin P. Tornai; McKinley, Randolph L.; Bowsher, James E.

    2005-01-01

    A compact, dedicated cadmium zinc telluride (CZT) gamma camera coupled with a fully three-dimensional (3-D) acquisition system may serve as a secondary diagnostic tool for volumetric molecular imaging of breast cancers, particularly in cases when mammographic findings are inconclusive. The developed emission mammotomography system comprises a medium field-of-view, quantized CZT detector and 3-D positioning gantry. The intrinsic energy resolution, sensitivity and spatial resolution of the dete...

  6. Floor Probe/Contamination Monitor (NE Model FLP3D) Test and Evaluation Report

    A floor contamination monitor model FLP3D manufactured by Saint-Gobain Crystals and Detectors UK Ltd. was tested at Oak Ridge National Laboratory. The purpose of the test is to evaluate the monitor's performance as a mobile instrument capable of detecting alpha and/or beta contamination that may exist on a flat surface such as a floor. The monitor consists of a large area scintillation probe (600 cm2) and a rate meter mounted on heavy-duty wheels with a 22 mm separation between the monitored surface and the probe. Performance was evaluated under normal and severe environmental conditions in terms of temperature and humidity variations, and exposure to RF and magnetic fields. Sensitivity measurements were also made to determine the probe's efficiency for detecting alpha and beta contamination. The overall performance of the floor monitor is considered satisfactory under the various environmental conditions with no major problems observed. The monitor is approximately 50% efficiency for 90Sr/90Y with the source placed in contact with the detector's protective grille (0 mm) and at a distance of 22 mm. However, in its present physical configuration, the floor monitor is inefficient in detecting alpha contamination due to the 22 mm separation between the surface to be monitored and the detector's surface. The alpha detection efficiency can be enhanced to a reasonable vale by redesigning the brackets holding the heavy-duty wheels to reduce the height between the surface to be monitored and the surface of the probe to a few millimeters. For use at ORNL, this change is recommended

  7. 3D-LIVE: D4.2 Second report on the experimentations and evaluations of the 3D-LIVE Tele-Immersive Environment

    Crowle, S.; Conte, M; Poussard, B.

    2015-01-01

    This report presents the final experimental phase conducted as part of the 3D-LIVE project. Technical progress that lead to this final phase includes new developments and refinements to existing work based on lessons learned from previous experimental work (see deliverable D4.1). These early experimental outcomes guided subsequent enhancements to the 3D-LIVE scenarios and the updates to the system prototype. In this final phase of investigation (LIVE3), the experimental focus has been refined...

  8. Impacted teeth in the maxilla: usefulness of 3D Dental-CT for preoperative evaluation

    Objective: To compare the shapes of roots of impacted teeth shown in three-dimensional computed tomographic images (3D Dental-computed tomography (CT) images) and plain radiographs and to determine whether 3D Dental-CT images are useful for examination before performing an operation for extraction of a maxillary impacted tooth. Methods and patients: Images obtained from patients who had impacted teeth in the maxilla, including impacted mesial supernumerary teeth in 13 patients, impacted incisors in two patients, impacted canines in 11 patients, impacted premolars in four patients and impacted molars in three patients, were used in this study. In all patients, plain radiographs and 3D Dental-CT images were retrospectively reviewed by an oral radiologist for evidence of root dilaceration before operations to extract the impacted teeth were performed. The findings in the images were compared with intraoperative findings in all cases. Results: The mean specificity and sensitivity of plain radiographs were 95 and 8%, respectively, while those of 3D Dental-CT images were 100 and 77%, respectively. There was a statistically significant (P<0.01) difference between the depiction capabilities of plain radiographs and 3D Dental-CT images with regard to dilacerations of roots of impacted teeth. Discussion and conclusion: CT may enable radiologists to make a quick and accurate diagnosis of tooth impaction. 3D Dental-CT images are useful for determining the root shape of an impacted tooth in the maxilla

  9. Evaluation of the 3d Urban Modelling Capabilities in Geographical Information Systems

    Dogru, A. O.; Seker, D. Z.

    2010-12-01

    Geographical Information System (GIS) Technology, which provides successful solutions to basic spatial problems, is currently widely used in 3 dimensional (3D) modeling of physical reality with its developing visualization tools. The modeling of large and complicated phenomenon is a challenging problem in terms of computer graphics currently in use. However, it is possible to visualize that phenomenon in 3D by using computer systems. 3D models are used in developing computer games, military training, urban planning, tourism and etc. The use of 3D models for planning and management of urban areas is very popular issue of city administrations. In this context, 3D City models are produced and used for various purposes. However the requirements of the models vary depending on the type and scope of the application. While a high level visualization, where photorealistic visualization techniques are widely used, is required for touristy and recreational purposes, an abstract visualization of the physical reality is generally sufficient for the communication of the thematic information. The visual variables, which are the principle components of cartographic visualization, such as: color, shape, pattern, orientation, size, position, and saturation are used for communicating the thematic information. These kinds of 3D city models are called as abstract models. Standardization of technologies used for 3D modeling is now available by the use of CityGML. CityGML implements several novel concepts to support interoperability, consistency and functionality. For example it supports different Levels-of-Detail (LoD), which may arise from independent data collection processes and are used for efficient visualization and efficient data analysis. In one CityGML data set, the same object may be represented in different LoD simultaneously, enabling the analysis and visualization of the same object with regard to different degrees of resolution. Furthermore, two CityGML data sets

  10. Transient analysis in the 3D nodal kinetics and thermal-hydraulics ANDES/COBRA coupled system

    Neutron kinetics has been implemented in the 3D nodal solver ANDES, which has been coupled to the core thermal-hydraulics (TH) code COBRA-III for core transient analysis. The purpose of this work is, first, to discuss and test the ability of the kinetics solver ANDES to model transients; and second, by means of a systematic analysis, including alternate kinetics schemes, time step size, nodal size, neutron energy groups and spectrum, to serve as a basis for the development of more accurate and efficient neutronics/thermal-hydraulics tools for general transient simulations. The PWR MOX/UO2 transient benchmark provided by the OECD/NEA and US NRC was selected for these goals. The obtained ANDES/COBRA-III results were consistent with other solutions to the benchmark; the differences in the TH feedback led to slight differences in the core power evolution, whereas very good agreements were found in the other requested parameters. The performed systematic analysis highlighted the optimum kinetics iterative scheme, and showed that neutronics spatial discretization effects have stronger influence than time discretization effects, in the semi-implicit scheme adopted, on the numerical solution. On the other hand, the number of energy groups has an important influence on the transient evolution, whereas the assumption of using the prompt neutron spectrum for delayed neutrons is acceptable as it leads to small relative errors. (authors)

  11. 3D simulations of the non-thermal broad-band emission from young supernova remnants including efficient particle acceleration

    Ferrand, Gilles; Safi-Harb, Samar

    2014-01-01

    Supernova remnants are believed to be the major contributors to Galactic cosmic rays. In this paper, we explore how the non-thermal emission from young remnants can be used to probe the production of energetic particles at the shock (both protons and electrons). Our model couples hydrodynamic simulations of a supernova remnant with a kinetic treatment of particle acceleration. We include two important back-reaction loops upstream of the shock: energetic particles can (i) modify the flow structure and (ii) amplify the magnetic field. As the latter process is not fully understood, we use different limit cases that encompass a wide range of possibilities. We follow the history of the shock dynamics and of the particle transport downstream of the shock, which allows us to compute the non-thermal emission from the remnant at any given age. We do this in 3D, in order to generate projected maps that can be compared with observations. We observe that completely different recipes for the magnetic field can lead to sim...

  12. Qualification of the 3D thermal hydraulics model of the code system TRACE based on plant data

    In the frame of the VVER-1000 Coolant Transient Benchmark Phase-1 the coupled code RELAP5/PARCS has been extensively assessed. The Phase-2 of this benchmark - currently underway - focuses on both multidimensional thermal hydraulics phenomena within the reactor pressure vessel (RPV) such as coolant mixing and core physics. Hence it is an excellent opportunity to qualify the prediction capability of the new coupled code system TRACE/PARCS taking into account plant data obtained from the Kozloduy nuclear power plant unit 6. In addition a lose coupling of CFX with RELAP5 is applied for the posttest calculation of the coolant mixing experiment. The developed multidimensional models of the VVER-1000 reactor pressure vessel as well as the performed calculations using these models are described in some detail. The predicted results are in good agreement with the data. It was demonstrated that the chosen 3D-nodalization of the RPV is adequate for the description of the coolant mixing phenomena in a VVER-1000 reactor. In addition selected results of the code TRACE/PARCS for a postulated main steam line transient (MSLB) are given. The investigations have shown that the multidimensional neutronics and thermal hydraulic model developed for the RPV of the VVER-1000 reactor are well qualified and consequently they are ready for their integration into a overall plant model so that the exercise 3 of the Phase 2 can be investigated as next. (authors)

  13. Qualification of the 3D thermal hydraulics model of the code system TRACE based on plant data

    Sanchez, V.H.; Jager, W. [Forschungzentrum Karlsruhe (FZK), Institute of Reactor Safety (IRS) (Germany); Kozlowski, T. [Royal Institute of Technology (KTH), Stockholm (Sweden)

    2007-07-01

    In the frame of the VVER-1000 Coolant Transient Benchmark Phase-1 the coupled code RELAP5/PARCS has been extensively assessed. The Phase-2 of this benchmark - currently underway - focuses on both multidimensional thermal hydraulics phenomena within the reactor pressure vessel (RPV) such as coolant mixing and core physics. Hence it is an excellent opportunity to qualify the prediction capability of the new coupled code system TRACE/PARCS taking into account plant data obtained from the Kozloduy nuclear power plant unit 6. In addition a lose coupling of CFX with RELAP5 is applied for the posttest calculation of the coolant mixing experiment. The developed multidimensional models of the VVER-1000 reactor pressure vessel as well as the performed calculations using these models are described in some detail. The predicted results are in good agreement with the data. It was demonstrated that the chosen 3D-nodalization of the RPV is adequate for the description of the coolant mixing phenomena in a VVER-1000 reactor. In addition selected results of the code TRACE/PARCS for a postulated main steam line transient (MSLB) are given. The investigations have shown that the multidimensional neutronics and thermal hydraulic model developed for the RPV of the VVER-1000 reactor are well qualified and consequently they are ready for their integration into a overall plant model so that the exercise 3 of the Phase 2 can be investigated as next. (authors)

  14. Development of a fast 3D thermal-hydraulic tool for design and safety studies for HTRS

    A three-dimensional thermal-hydraulic code called TH3D is being developed at the Institute of Nuclear Technology and Energy Systems (IKE), University of Stuttgart. The objective of this endeavor is to provide a tool which can be used to analyze, design, and safety related issues in high temperature reactors. The tool shall be generally applicable for modular HTRs. Operational conditions with forced cooling as well as accident situations with heat removal by conduction and natural circulation shall be covered. Coupling to a reactor physics code shall be provided to account for the feedback of neutronics and thermal-hydraulics. Emphasis is on capturing essential effects resulting from three-dimensional features (e.g. power distribution with block-type fuel elements) rather than on a high level of detail, in order to keep computation times reasonably low. In general, we strive for a quick-turn analysis that provides enough insight to make informed decisions that cannot wait for the extensive time it takes to conduct in-depth, detailed analyses, e.g. with large CFD models. The physical and numerical basics of the new code are given. The porous media approach is applied. The time dependent mass and energy conservation equations and simplified steady-state momentum conservation equations (dominance of friction) are solved for the cooling gas along with the time dependent energy conservation equation for the solid. An appropriate set of constitutive equations (e.g. effective heat conductivity of solid, pressure drop, heat transfer coefficient, etc.) is applied. A finite-volume method is used for the spatial discretisation. A fully implicit method with adaptive time step selection is applied for the temporal integration in transient problems. In this paper results of calculations for a benchmark design defined by OECD/NEA/NSC [Reitsma, F., 2004. PBMR Coupled Neutronics/Thermal Hydraulics Transient Benchmark the PBMR-400 Core Design. PBMR Company Ltd., South Africa] are

  15. Study of the initiation and the propagation of cracks under 3D thermal cyclic loading; Etude de l'amorcage et de la propagation des fissures sous chargement thermique cyclique 3D

    Ancelet, O

    2005-07-01

    The incident which has occurred on the Civaux power plant has shown the noxiousness of thermal loading and the difficulty to take it into account at design level. The objective of this report is to study the initiation and the propagation of crack under thermal loading. In this aim the CEA has developed a new experiment named FAT3D. The various experiments carried out showed the harmfulness of a thermal loading, which makes it possible to rapidly initiate a network of cracks and to propagate one (or some) cracks through the totally thickness of the component under certain conditions. These experimental results associated with a mechanical analysis put at fault the usual criteria of damage based on the variations of the equivalent strain. In addition, the study of the propagation stage shows the importance of the plasticity which, in the case of a thermal loading, slows down the propagation of the crack. (author)

  16. Solar Thermal Concept Evaluation

    Hawk, Clark W.; Bonometti, Joseph A.

    1995-01-01

    Concentrated solar thermal energy can be utilized in a variety of high temperature applications for both terrestrial and space environments. In each application, knowledge of the collector and absorber's heat exchange interaction is required. To understand this coupled mechanism, various concentrator types and geometries, as well as, their relationship to the physical absorber mechanics were investigated. To conduct experimental tests various parts of a 5,000 watt, thermal concentrator, facility were made and evaluated. This was in anticipation at a larger NASA facility proposed for construction. Although much of the work centered on solar thermal propulsion for an upper stage (less than one pound thrust range), the information generated and the facility's capabilities are applicable to material processing, power generation and similar uses. The numerical calculations used to design the laboratory mirror and the procedure for evaluating other solar collectors are presented here. The mirror design is based on a hexagonal faceted system, which uses a spherical approximation to the parabolic surface. The work began with a few two dimensional estimates and continued with a full, three dimensional, numerical algorithm written in FORTRAN code. This was compared to a full geometry, ray trace program, BEAM 4, which optimizes the curvatures, based on purely optical considerations. Founded on numerical results, the characteristics of a faceted concentrator were construed. The numerical methodologies themselves were evaluated and categorized. As a result, the three-dimensional FORTRAN code was the method chosen to construct the mirrors, due to its overall accuracy and superior results to the ray trace program. This information is being used to fabricate and subsequently, laser map the actual mirror surfaces. Evaluation of concentrator mirrors, thermal applications and scaling the results of the 10 foot diameter mirror to a much larger concentrator, were studied. Evaluations

  17. Development and verification of the coupled 3D neutron kinetics/thermal-hydraulics code DYN3D-HTR for the simulation of transients in block-type HTGR

    DYN3D is a nodal diffusion code for 3D steady-state and transient analysis of Light Water Reactor (LWR) cores with hexagonal or square fuel element geometry. In addition to the neutron kinetics, it comprises of a thermal-hydraulics model for flow in parallel coolant channels. Macroscopic cross section data libraries generated with variation of burn-up, reactor poisons concentrations and thermal-hydraulic feedback parameters are linked to the code. Two-group and multi-groups versions of the code are available. Currently, at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the DYN3D code is being extended and adopted for the application to block-type High Temperature Gas-Cooled Reactors (HTGRs). In this paper, we give an overview of the latest developments of DYN3D concerning block-type HTGR. The simplified P3 (SP3) transport approximation is implemented into the multi-group DYN3D code to take anisotropy of the neutron flux and heterogeneity of the core more precisely into account. The SP3 method previously implemented into DYN3D for square fuel element geometry of LWR is being extended for hexagonal geometry of the graphite blocks, where the hexagons are subdivided into triangular nodes to be able to perform a systematic mesh refinement. One of the main challenges in cross section generation for the HTGR core calculations is the treatment of the so-called “double heterogeneity”. The modified Reactivity-Equivalent Physical Transformation (RPT) approach is applied in order to eliminate the double-heterogeneity of HTGR fuel elements in the deterministic lattice calculations. The main steps of the RPT method are described. The use of the method for the cross section generation of a simplified HTGR core including its verification is presented. A 3D heat conduction module coupled with a channel-type coolant flow model is implemented to take the temperature reactivity feedback to neutronics physically correctly into account. It is shown that there is significant

  18. A hybrid radial basis function-pseudospectral method for thermal convection in a 3-D spherical shell

    Wright, G. B.

    2010-07-01

    A novel hybrid spectral method that combines radial basis function (RBF) and Chebyshev pseudospectral methods in a "2 + 1" approach is presented for numerically simulating thermal convection in a 3-D spherical shell. This is the first study to apply RBFs to a full 3-D physical model in spherical geometry. In addition to being spectrally accurate, RBFs are not defined in terms of any surface-based coordinate system such as spherical coordinates. As a result, when used in the lateral directions, as in this study, they completely circumvent the pole issue with the further advantage that nodes can be "scattered" over the surface of a sphere. In the radial direction, Chebyshev polynomials are used, which are also spectrally accurate and provide the necessary clustering near the boundaries to resolve boundary layers. Applications of this new hybrid methodology are given to the problem of convection in the Earth\\'s mantle, which is modeled by a Boussinesq fluid at infinite Prandtl number. To see whether this numerical technique warrants further investigation, the study limits itself to an isoviscous mantle. Benchmark comparisons are presented with other currently used mantle convection codes for Rayleigh number (Ra) 7 × 103 and 105. Results from a Ra = 106 simulation are also given. The algorithmic simplicity of the code (mostly due to RBFs) allows it to be written in less than 400 lines of MATLAB and run on a single workstation. We find that our method is very competitive with those currently used in the literature. Copyright 2010 by the American Geophysical Union.

  19. Exploring single-molecule interactions through 3D optical trapping and tracking: From thermal noise to protein refolding

    Wong, Wesley Philip

    The focus of this thesis is the development and application of a novel technique for investigating the structure and dynamics of weak interactions between and within single-molecules. This approach is designed to explore unusual features in bi-directional transitions near equilibrium. The basic idea is to infer molecular events by observing changes in the three-dimensional Brownian fluctuations of a functionalized microsphere held weakly near a reactive substrate. Experimentally, I have developed a unique optical tweezers system that combines an interference technique for accurate 3D tracking (˜1 nm vertically, and ˜2-3 nm laterally) with a continuous autofocus system which stabilizes the trap height to within 1-2 mn over hours. A number of different physical and biological systems were investigated with this instrument. Data interpretation was assisted by a multi-scale Brownian Dynamics simulation that I have developed. I have explored the 3D signatures of different molecular tethers, distinguishing between single and multiple attachments, as well as between stiff and soft linkages. As well, I have developed a technique for measuring the force-dependent compliance of molecular tethers from thermal noise fluctuations and demonstrated this with a short ssDNA oligomer. Another practical approach that I have developed for extracting information from fluctuation measurements is Inverse Brownian Dynamics, which yields the underlying potential of mean force and position dependent diffusion coefficient from the Brownian motion of a particle. I have also developed a new force calibration method that takes into account video motion blur, and that uses this information to measure bead dynamics. Perhaps most significantly, I have trade the first direct observations of the refolding of spectrin repeats under mechanical force, and investigated the force-dependent kinetics of this transition.

  20. Use of 3D MR reconstructions in the evaluation of glenoid bone loss: a clinical study

    To assess the ability of 3D MR shoulder reconstructions to accurately quantify glenoid bone loss in the clinical setting using findings at the time of arthroscopy as the gold standard. Retrospective review of patients with MR shoulder studies that included 3D MR reconstructions (3D MR) produced using an axial Dixon 3D-T1W-FLASH sequence at our institution was conducted with the following inclusion criteria: history of anterior shoulder dislocation, arthroscopy (OR) performed within 6 months of the MRI, and an estimate of glenoid bone loss made in the OR using the bare-spot method. Two musculoskeletal radiologists produced estimates of bone loss along the glenoid width, measured in mm and %, on 3D MR using the best-fit circle method, which were then compared to the OR measurements. There were a total of 15 patients (13 men, two women; mean age, 28, range, 19-51 years). There was no significant difference, on average, between the MRI (mean 3.4 mm/12.6 %; range, 0-30 %) and OR (mean, 12.7 %; range, 0-30 %) measurements of glenoid bone loss (p = 0.767). A 95 % confidence interval for the mean absolute error extended from 0.45-2.21 %, implying that, when averaged over all patients, the true mean absolute error of the MRI measurements relative to the OR measurements is expected to be less than 2.21 %. Inter-reader agreement between the two readers had an IC of 0.92 and CC of 0.90 in terms of percentage of bone loss. 3D MR reconstructions of the shoulder can be used to accurately measure glenoid bone loss. (orig.)

  1. Use of 3D MR reconstructions in the evaluation of glenoid bone loss: a clinical study

    Gyftopoulos, Soterios; Beltran, Luis S.; Yemin, Avner; Recht, Michael P. [NYU Langone Medical Center, Department of Radiology, New York, NY (United States); Strauss, Eric; Meislin, Robert; Jazrawi, Laith [NYU Langone Medical Center, Center for Musculoskeletal Care, Department of Orthopaedic Surgery, New York, NY (United States)

    2014-02-15

    To assess the ability of 3D MR shoulder reconstructions to accurately quantify glenoid bone loss in the clinical setting using findings at the time of arthroscopy as the gold standard. Retrospective review of patients with MR shoulder studies that included 3D MR reconstructions (3D MR) produced using an axial Dixon 3D-T1W-FLASH sequence at our institution was conducted with the following inclusion criteria: history of anterior shoulder dislocation, arthroscopy (OR) performed within 6 months of the MRI, and an estimate of glenoid bone loss made in the OR using the bare-spot method. Two musculoskeletal radiologists produced estimates of bone loss along the glenoid width, measured in mm and %, on 3D MR using the best-fit circle method, which were then compared to the OR measurements. There were a total of 15 patients (13 men, two women; mean age, 28, range, 19-51 years). There was no significant difference, on average, between the MRI (mean 3.4 mm/12.6 %; range, 0-30 %) and OR (mean, 12.7 %; range, 0-30 %) measurements of glenoid bone loss (p = 0.767). A 95 % confidence interval for the mean absolute error extended from 0.45-2.21 %, implying that, when averaged over all patients, the true mean absolute error of the MRI measurements relative to the OR measurements is expected to be less than 2.21 %. Inter-reader agreement between the two readers had an IC of 0.92 and CC of 0.90 in terms of percentage of bone loss. 3D MR reconstructions of the shoulder can be used to accurately measure glenoid bone loss. (orig.)

  2. Steering in loco-regional deep hyperthermia: evaluation of common practice with 3D-planning

    Full text: Radiotherapy plus hyperthermia is standard treatment for locally advanced cervical cancer. In our unit the hyperthermia treatment of these patients is performed with a BSD 2000 3D deep hyperthermia system. In order to apply loco-regional deep hyperthermia at a maximum dose level, protocolized SAR steering is used to optimize tumor temperatures, avoid toxicity and minimize complaints due to local overheating. SAR steering is the term we use to address all changes in antenna settings that affect the distribution of dissipated power. The protocol used to guide SAR steering reflects an empirical strategy based on the experience gathered over the last decade. With the availability of sophisticated codes to predict patient specific EM fields, we are now able to prospectively evaluate the effectiveness of the applied amplitude and phase settings, and of the steering protocol. In this study, we evaluate the effect of prescribed steering actions in a patient model according to the treatment protocol. In particular, we assess the effectiveness of both phase and amplitude steering to control power dissipation at the tumor location and at the surface. From the simulations it is clear that the SAR focus within the pelvis falls apart in three different maxima. One located at the ventral side and associated with the os pubis, one located at the backside and associated with the lumbosacral vertebrae, and one in the middle associated with the tumor volume. Instead of continuously shifting the SAR focus, both phase- and amplitude steering in the AP direction merely changes the ratio of dissipated power in the three different areas. To elucidate the difference between phase and amplitude steering in the AP direction, we divide our patient model in three regions of interest. These regions are indicated as front (f), middle (m) and back (b). For these regions total integrated power absorption was calculated at a range of phase and amplitude settings. In figure 1a the ratio

  3. 3D-2D registration in mobile radiographs: algorithm development and preliminary clinical evaluation

    Otake, Yoshito; Wang, Adam S.; Uneri, Ali; Kleinszig, Gerhard; Vogt, Sebastian; Aygun, Nafi; Lo, Sheng-fu L.; Wolinsky, Jean-Paul; Gokaslan, Ziya L.; Siewerdsen, Jeffrey H.

    2015-03-01

    An image-based 3D-2D registration method is presented using radiographs acquired in the uncalibrated, unconstrained geometry of mobile radiography. The approach extends a previous method for six degree-of-freedom (DOF) registration in C-arm fluoroscopy (namely ‘LevelCheck’) to solve the 9-DOF estimate of geometry in which the position of the source and detector are unconstrained. The method was implemented using a gradient correlation similarity metric and stochastic derivative-free optimization on a GPU. Development and evaluation were conducted in three steps. First, simulation studies were performed that involved a CT scan of an anthropomorphic body phantom and 1000 randomly generated digitally reconstructed radiographs in posterior-anterior and lateral views. A median projection distance error (PDE) of 0.007 mm was achieved with 9-DOF registration compared to 0.767 mm for 6-DOF. Second, cadaver studies were conducted using mobile radiographs acquired in three anatomical regions (thorax, abdomen and pelvis) and three levels of source-detector distance (~800, ~1000 and ~1200 mm). The 9-DOF method achieved a median PDE of 0.49 mm (compared to 2.53 mm for the 6-DOF method) and demonstrated robustness in the unconstrained imaging geometry. Finally, a retrospective clinical study was conducted with intraoperative radiographs of the spine exhibiting real anatomical deformation and image content mismatch (e.g. interventional devices in the radiograph that were not in the CT), demonstrating a PDE = 1.1 mm for the 9-DOF approach. Average computation time was 48.5 s, involving 687 701 function evaluations on average, compared to 18.2 s for the 6-DOF method. Despite the greater computational load, the 9-DOF method may offer a valuable tool for target localization (e.g. decision support in level counting) as well as safety and quality assurance checks at the conclusion of a procedure (e.g. overlay of planning data on the radiograph for verification of

  4. Thermal evaluation of buildings

    Barajas, Luís M; Roset Calzada, Jaime; La Ferla, Giuseppe

    2015-01-01

    To COST ACTION TU 1104 "Smart Energy Regions" Prof. Aleksandra Djukic and Prof. Aleksandra Krstic-Furundzic of the Faculty of Architecture of the University of Belgrade, Serbia, that gave us the opportunity of be part of the training school imparted from Monday 20th to Thursday 23rd April 2015, where we can teach the topic. The convenience of the use of environmental building evaluation tools, to know design conditions and thermal behavior, by using bioclimatic strategies fo...

  5. Quantitative evaluation of temporal partial coherence using 3D Fourier transforms of through-focus TEM images

    We evaluate the temporal partial coherence of transmission electron microscopy (TEM) using the three-dimensional (3D) Fourier transform (FT) of through-focus images. Young's fringe method often indicates the unexpected high-frequency information due to non-linear imaging terms. We have already used the 3D FT of axial (non-tilted) through-focus images to reduce the effect of non-linear terms on the linear imaging term, and demonstrated the improvement of monochromated lower-voltage TEM performance [Kimoto et al., Ultramicroscopy 121 (2012) 31–39]. Here we apply the 3D FT method with intentionally tilted incidence to normalize various factors associated with a TEM specimen and an imaging device. The temporal partial coherence of two microscopes operated at 30, 60 and 80 kV is evaluated. Our method is applicable to such cases where the non-linear terms become more significant in lower acceleration voltage or aberration-corrected high spatial resolution TEM. - Highlights: • We assess the temporal partial coherence of TEM using a 3-dimensional (3D) Fourier transform (FT) of through-focus images. • We apply the 3D FT method with intentionally tilted incidence to normalize various factors associated with a TEM specimen and an imaging device. • The spatial frequency at which information transfer decreases to 1/e2 (13.5%) is determined for two lower-voltage TEM systems

  6. 3D thermal and hydrodynamic modelling of the elaboration of glass in a process of cold crucible direct induction and with stirring techniques

    The aim of this work is to implement a numerical modelling of the thermal hydrodynamical and electromagnetic phenomena in the glass bath in order to support the dimensioning of the cold crucible direct induction vitrification process. Two configurations equipped with a mechanical stirrer are presented: a pseudo-3D (EREBUS pilot, cold crucible of internal diameter: 500 mm) and a 3D case (PEV pilot, nuclearized cold crucible configuration). (O.M.)

  7. Evaluation and Performance Analysis of 3D Printing Technique for Ka-Band Antenna Production

    Armendariz, Unai; Rommel, Simon; Rodríguez Páez, Juan Sebastián;

    2016-01-01

    This paper presents the design and fabrication of 3D printed WR-28 waveguide horn antennas operating in the Ka-band frequency range between 26.5GHz and 40GHz. Three antennas are fabricated from polylactide acid filaments in conductive and non-conductive variants; the latter is covered with...

  8. Light 3D localizer for surgical use: application to radiation therapy field evaluation

    We present a small 3D-localization and acquisition device using standard CCD cameras and connected to a Personal Computer (PC) parallel port. The system has been tested on phantoms and on radiation therapy planning with an animal model. (author)

  9. 3-D intestinal scaffolds for evaluating the therapeutic potential of probiotics.

    Costello, Cait M; Sorna, Rachel M; Goh, Yih-Lin; Cengic, Ivana; Jain, Nina K; March, John C

    2014-07-01

    Biomimetic in vitro intestinal models are becoming useful tools for studying host-microbial interactions. In the past, these models have typically been limited to simple cultures on 2-D scaffolds or Transwell inserts, but it is widely understood that epithelial cells cultured in 3-D environments exhibit different phenotypes that are more reflective of native tissue, and that different microbial species will preferentially adhere to select locations along the intestinal villi. We used a synthetic 3-D tissue scaffold with villous features that could support the coculture of epithelial cell types with select bacterial populations. Our end goal was to establish microbial niches along the crypt-villus axis in order to mimic the natural microenvironment of the small intestine, which could potentially provide new insights into microbe-induced intestinal disorders, as well as enabling targeted probiotic therapies. We recreated the surface topography of the small intestine by fabricating a biodegradable and biocompatible villous scaffold using poly lactic-glycolic acid to enable the culture of Caco-2 with differentiation along the crypt-villus axis in a similar manner to native intestines. This was then used as a platform to mimic the adhesion and invasion profiles of both Salmonella and Pseudomonas, and assess the therapeutic potential of Lactobacillus and commensal Escherichia coli in a 3-D setting. We found that, in a 3-D environment, Lactobacillus is more successful at displacing pathogens, whereas Nissle is more effective at inhibiting pathogen adhesion. PMID:24798584

  10. Evaluation of Gastric Volumes: Comparison of 3-D Ultrasound and Magnetic Resonance Imaging.

    Buisman, Wijnand J; Mauritz, Femke A; Westerhuis, Wouter E; Gilja, Odd Helge; van der Zee, David C; van Herwaarden-Lindeboom, Maud Y A

    2016-07-01

    To investigate gastric accommodation, accurate measurements of gastric volumes are necessary. An excellent technique to measure gastric volumes is dynamic magnetic resonance imaging (MRI). Unfortunately, dynamic MRI is expensive and not always available. A new 3-D ultrasound (US) method using a matrix transducer was developed to measure gastric volumes. In this prospective study, 14 healthy volunteers underwent a dynamic MRI and a 3-D US. Gastric volumes were calculated with intra-gastric liquid content and total gastric volume. Mean postprandial liquid gastric content was 397 ± 96.5 mL. Mean volume difference was 1.0 mL with limits of agreement of -8.9 to 10.9 mL. When gastric air was taken into account, mean total gastric volume was 540 ± 115.4 mL SD. Mean volume difference was 2.3 mL with limits of agreement of -21.1 to 26.4 mL. The matrix 3-D US showed excellent agreement with dynamic MRI. Therefore matrix 3-D US is a reliable alternative to measure gastric volumes. PMID:27067418